{"gene":"KCNA4","run_date":"2026-04-28T18:06:54","timeline":{"discoveries":[{"year":1991,"finding":"KCNA4 (HK1/hPCN2) was molecularly cloned from human ventricle and functionally expressed in Xenopus oocytes, demonstrating it encodes a rapidly inactivating voltage-gated K+ channel with sensitivity to 4-aminopyridine.","method":"cDNA cloning, Xenopus oocyte expression, two-electrode voltage clamp","journal":"FASEB journal","confidence":"High","confidence_rationale":"Tier 1 — original functional reconstitution in heterologous system with electrophysiological characterization","pmids":["2001794"],"is_preprint":false},{"year":1991,"finding":"The hPCN1 isoform (related to KCNA4) expressed in Xenopus oocytes produces a slowly inactivating outward K+ current inhibited by 4-aminopyridine, establishing the electrophysiological signature of human Shaker-family channels including Kv1.4.","method":"cDNA isolation, Xenopus oocyte expression, two-electrode voltage clamp","journal":"Proceedings of the National Academy of Sciences","confidence":"High","confidence_rationale":"Tier 1 — functional reconstitution with pharmacological characterization","pmids":["1986382"],"is_preprint":false},{"year":1993,"finding":"Kv1.4 co-assembles with non-inactivating Kv1 subunits (Kv1.1, Kv1.2, Kv1.5) to form heteromultimeric channels; a single inactivating Kv1.4 subunit is sufficient to confer inactivation on the heteromeric complex, and hybrid channels display recovery kinetics closer to native cardiac transient outward current.","method":"Co-injection of cRNAs in Xenopus oocytes, two-electrode voltage clamp","journal":"Circulation research","confidence":"High","confidence_rationale":"Tier 1 — direct reconstitution of heteromultimers with functional characterization","pmids":["8495559"],"is_preprint":false},{"year":1994,"finding":"The mouse Kcna4/Kv1.4 gene is contained in a single coding exon encoding a 654-amino-acid protein; the 5' NCR contains SP1 repeats and lacks TATA box; ATTTA repeats in the 3' NCR of the longer transcript reduce translational efficiency; the gene maps to mouse chromosome 2 and human chromosome 11p14.","method":"Genomic cloning, sequencing, Xenopus oocyte expression, in situ hybridization, fluorescence mapping","journal":"Genomics","confidence":"High","confidence_rationale":"Tier 1 — direct genomic characterization and functional expression","pmids":["8020965"],"is_preprint":false},{"year":1995,"finding":"C-type inactivation governs recovery from inactivation in Kv1.4: removal of the N-terminal ball domain (fast inactivation) revealed a slow C-type inactivation process, and recovery rates from N-type and C-type inactivated states are nearly identical, indicating C-type inactivation is the rate-limiting step for recovery.","method":"N-terminal deletion mutagenesis, Xenopus oocyte two-electrode voltage clamp, site-directed mutagenesis of S4 voltage sensor (R454Q)","journal":"The Journal of physiology","confidence":"High","confidence_rationale":"Tier 1 — reconstitution with mutagenesis and biophysical analysis","pmids":["8788936"],"is_preprint":false},{"year":1995,"finding":"Kv beta 3 co-expressed with Kv1.4 alpha-subunit accelerates both fast and slow components of inactivation, increases contribution of the slow inactivation component, slows recovery from inactivation (for intact Kv1.4 but not N-terminal deletion mutant), and slows deactivation, demonstrating that beta subunits modulate post-activation channel states.","method":"Xenopus oocyte co-expression, two-electrode voltage clamp","journal":"The American journal of physiology","confidence":"High","confidence_rationale":"Tier 1 — direct reconstitution of alpha-beta subunit complex with functional analysis","pmids":["7631872"],"is_preprint":false},{"year":1995,"finding":"PSD-95 family MAGUKs cluster Kv1.4 at the cell surface through direct binding of the channel's C-terminal cytoplasmic tail to PDZ domains of PSD-95, establishing the PDZ-mediated clustering mechanism for Shaker-type K+ channels.","method":"Yeast two-hybrid, co-immunoprecipitation, heterologous cell co-expression, immunofluorescence clustering assay","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 — reciprocal biochemical and cell biological evidence replicated across labs","pmids":["7477295"],"is_preprint":false},{"year":1996,"finding":"The C-terminal -ETDV sequence of Kv1.4 is required for binding to and clustering with SAP97 and PSD-95; mutation of this motif abolishes both binding and clustering; PSD-95 induces cell-surface plaque-like clusters while SAP97 causes intracellular aggregates, demonstrating differential clustering activity of MAGUK family members.","method":"C-terminal deletion mutagenesis, heterologous cell co-expression, immunofluorescence","journal":"Neuropharmacology","confidence":"High","confidence_rationale":"Tier 2 — mutagenesis identifies specific binding motif, multiple orthogonal assays","pmids":["8938729"],"is_preprint":false},{"year":1996,"finding":"Oxidizing cysteine-modifying reagents (DTBNP, chloramine-T) remove N-type inactivation of Kv1.4 and slow deactivation, effects reversed by DTT, indicating that redox state of cysteine residue(s) in the N-terminal inactivation domain regulates channel gating.","method":"Whole-cell patch clamp in HEK-293 cells expressing rat Kv1.4, cysteine-specific oxidizing/reducing agents","journal":"Pflugers Archiv","confidence":"Medium","confidence_rationale":"Tier 2 — direct pharmacological manipulation with electrophysiological readout, single lab","pmids":["8584439"],"is_preprint":false},{"year":1996,"finding":"The mouse Kv1.4 transcription unit produces two mRNAs (3.5 kb and 4.5 kb) from a common start site; ATTTA repeats in the 3' NCR of the longer transcript reduce translational efficiency ~4–5-fold compared with the shorter transcript; the basal promoter is GC-rich with SP1 repeats and lacks tissue specificity.","method":"5' RACE, reporter assays, Xenopus oocyte expression of individual transcripts","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 — direct functional comparison of transcripts in expression system","pmids":["8663090"],"is_preprint":false},{"year":1997,"finding":"CaMKII phosphorylation of an N-terminal residue of Kv1.4 slows inactivation gating and accelerates recovery from N-type inactivation; dephosphorylation by calcineurin accelerates inactivation 5–10-fold and promotes cumulative inactivation; the balance is regulated by intracellular Ca2+ concentration, making Kv1.4 inactivation Ca2+-sensitive.","method":"Xenopus oocyte expression, two-electrode voltage clamp, CaMKII and calcineurin application, frequency-dependent stimulation protocols","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 1 — enzyme applied directly to channel, functional readout with mechanistic specificity","pmids":["9133364"],"is_preprint":false},{"year":1997,"finding":"Kvbeta1.1 and Kvbeta2.1 subunits accelerate Kv1.4 activation kinetics without altering voltage dependence of activation or steady-state inactivation; Kvbeta2.1 modestly lengthens the slow time constant of recovery from inactivation.","method":"Xenopus oocyte co-expression, two-electrode voltage clamp","journal":"Pflugers Archiv","confidence":"Medium","confidence_rationale":"Tier 1 — direct reconstitution, single lab","pmids":["9359902"],"is_preprint":false},{"year":1997,"finding":"A truncated Kv1.1 polypeptide (Kv1.1N206Tag) forms heteromultimeric complexes with native Kv1.4 and Kv1.5 in GH3 cells and is retained in the endoplasmic reticulum, providing a dominant-negative mechanism for long QT syndrome by trapping native channels in the ER.","method":"Double immunoprecipitation with channel-specific antibodies, subcellular fractionation, immunofluorescence/confocal colocalization, RNase protection assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal biochemical methods demonstrating complex formation and ER retention","pmids":["9334228"],"is_preprint":false},{"year":1996,"finding":"N-type inactivation in Kv1.4 requires only a single inactivating subunit in heteromultimers; the proximal N-terminal region is critical; large deletions in the linker between the inactivation region and first transmembrane domain do not affect inactivation rate, suggesting the inactivation particle remains near the permeation pathway in the open state.","method":"Xenopus oocyte expression of Kv1.4-Kv1.5 tandems and co-expressed subunits, N-terminal deletion mutagenesis, two-electrode voltage clamp","journal":"The Journal of membrane biology","confidence":"High","confidence_rationale":"Tier 1 — tandem fusion constructs and mutagenesis with functional characterization","pmids":["8661510"],"is_preprint":false},{"year":1998,"finding":"PSD-95 is palmitoylated on N-terminal cysteines 3 and 5, which is required for its partitioning as an integral membrane protein and for PDZ-mediated interaction with Kv1.4 in vivo; palmitoylation-deficient PSD-95 mutants fail to interact with Kv1.4 in living cells.","method":"Metabolic labeling with [3H]palmitate, mutagenesis of Cys3/Cys5, cell fractionation, co-immunoprecipitation","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 1 — biochemical identification of PTM with mutagenesis and functional consequence on channel interaction","pmids":["9459448"],"is_preprint":false},{"year":1998,"finding":"Kv1.4-containing channels are localized presynaptically on axons and near excitatory synaptic boutons in hippocampal perforant path and mossy fiber regions, as determined by immunofluorescence and ultrastructural immunogold electron microscopy.","method":"Confocal immunofluorescence, electron microscopic immunocytochemistry with anti-Kv1.4 antibody","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 — ultrastructural localization with subcellular resolution","pmids":["9437018"],"is_preprint":false},{"year":1998,"finding":"Targeted deletion of Kv1.4 in mice does not eliminate the rapidly inactivating transient outward current (Ito) in adult ventricular myocytes; Kv4 subfamily channels are not upregulated in knockout mice, indicating Kv1.4 is not the primary molecular basis of Ito in adult murine ventricle.","method":"Targeted gene disruption (knockout mice), whole-cell patch clamp of isolated ventricular myocytes, Western blot","journal":"The Journal of physiology","confidence":"High","confidence_rationale":"Tier 2 — clean genetic knockout with electrophysiological readout in primary cells","pmids":["9547391"],"is_preprint":false},{"year":1998,"finding":"Kvbeta1.2 has three separable effects on Kv1.4: (1) a current-enhancing effect via the C-terminus, (2) allosteric enhancement of N-type inactivation by the alpha-ball, and (3) direct open-channel block by the beta-ball; the alpha-beta interaction is restricted to the N-terminus of Kv1.4 and C-terminus of Kvbeta1.2, with no direct interaction between the Kv1.4 alpha-ball and the Kvbeta subunit.","method":"Xenopus oocyte co-expression, two-electrode voltage clamp, N-terminal deletion mutants of Kv1.4, Kvbeta domain deletion mutants, yeast two-hybrid","journal":"The Journal of physiology","confidence":"High","confidence_rationale":"Tier 1 — mutagenesis of both subunits combined with functional reconstitution and protein interaction assays","pmids":["9763623"],"is_preprint":false},{"year":1998,"finding":"Antisense knockdown of Kv1.4 in rat hippocampus eliminates both early- and late-phase LTP and reduces paired-pulse facilitation in CA1 neurons without affecting spatial memory or dentate gyrus LTP, demonstrating a presynaptic role for Kv1.4 in CA1 LTP.","method":"Intraventricular antisense oligodeoxyribonucleotide injection, RT-PCR, Western blot, in vivo electrophysiology, Morris water maze behavioral testing","journal":"Proceedings of the National Academy of Sciences","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo knockdown with multiple electrophysiological and behavioral readouts, single lab","pmids":["9844011"],"is_preprint":false},{"year":1999,"finding":"N-terminal cysteines 3 and 5 of PSD-95 are essential for PSD-95 self-association (multimerization) and formation of cell-surface clusters with Kv1.4, but not for membrane association or binary binding to Kv1.4; multimerization is required for ternary complex formation with Kv1.4 and Fasciclin II.","method":"Mutagenesis of PSD-95 N-terminal cysteines, heterologous cell co-expression, immunofluorescence clustering assay, co-immunoprecipitation","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — mutagenesis with multiple functional assays distinguishing binary binding from multimerization-dependent clustering","pmids":["9867876"],"is_preprint":false},{"year":1999,"finding":"Regional differences in rat ventricular Ito are explained by differential expression of Kv1.4 (encoding slow-recovering Ito) and Kv4.2/Kv4.3 (encoding fast-recovering Ito); Kv1.4 protein and mRNA correlate with slow Ito density, and Kv1.4 kinetics in heterologous cells match slow Ito in myocytes.","method":"Western blot, Northern blot, patch clamp of ventricular myocytes and tsa-201 cells expressing individual channel subunits","journal":"The American journal of physiology","confidence":"High","confidence_rationale":"Tier 2 — protein/mRNA correlation with direct functional comparison in heterologous system","pmids":["10330244"],"is_preprint":false},{"year":1999,"finding":"Kv1 channel subunit composition determines surface expression: homotetrameric Kv1.4 localizes to the cell surface, while Kv1.1 is retained in ER; heteromeric assembly with Kv1.4 increases surface expression of Kv1.1 and Kv1.2 in a dose-dependent manner; Kvbeta subunits promote surface expression of each Kv1 complex.","method":"Transfection of mammalian cells and hippocampal neurons, immunofluorescence, surface biotinylation, Western blot","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — systematic comparison of homo- and heteromers with direct surface expression measurement","pmids":["10896669"],"is_preprint":false},{"year":2000,"finding":"Acidosis inhibits Kv1.4 during repetitive pulsing by slowing recovery from N-type inactivation; protonation of extracellular histidine H508 enhances C-type inactivation, which in turn slows recovery from N-type inactivation; elevated [K+]o and the K532Y mutation also abolish the slowing effect, linking extracellular pore gating to N-type inactivation recovery.","method":"Xenopus oocyte two-electrode voltage clamp, site-directed mutagenesis (H508Q, K532Y), N-terminal deletion mutants, ion substitution experiments","journal":"The Journal of physiology","confidence":"High","confidence_rationale":"Tier 1 — mutagenesis identifies specific residue, multiple orthogonal perturbations","pmids":["10896716"],"is_preprint":false},{"year":2000,"finding":"PSD-95 clustering completely suppresses Kv1.4 internalization (t1/2 = 87 min when alone); a non-clustering mutant C35S-PSD-95 enhances internalization rate (t1/2 = 16 min); clustering is necessary and sufficient for internalization suppression, revealing a new role for PSD-95 in stabilizing channels at the cell surface.","method":"Cell-surface biotinylation assay in transfected HEK293 cells, GFP-tagged Kv1.4 co-expression, electrophysiology","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — quantitative surface biotinylation with clustering mutants, functional electrophysiological controls","pmids":["10625685"],"is_preprint":false},{"year":2000,"finding":"Genetic elimination of both Ito,f (Kv4.2W362F dominant-negative) and Ito,s (Kv1.4 knockout) in mice causes marked QT prolongation, atrioventricular block, ventricular tachycardia, and early afterdepolarizations, demonstrating that upregulation of Kv1.4 underlies the slow Ito in Kv4.2W362F-expressing ventricles and that both currents together are required for normal cardiac electrical function.","method":"Transgenic/knockout mouse cross (Kv4.2W362F x Kv1.4-/-), in vivo telemetric ECG, patch clamp of isolated ventricular myocytes, histology, echocardiography","journal":"Circulation research","confidence":"High","confidence_rationale":"Tier 2 — clean double-genetic model with in vivo and ex vivo electrophysiological phenotyping","pmids":["10884375"],"is_preprint":false},{"year":2000,"finding":"ACTH potently and rapidly reduces Kv1.4 mRNA expression in bovine adrenal zona fasciculata cells (t1/2 ~1 h, IC50 ~1.2 pM) via a cAMP/PKA-partially dependent mechanism, leading to decreased A-type current over 72 h, demonstrating pretranslational regulation of Kv1.4 by the hypothalamic-pituitary-adrenal axis.","method":"cDNA cloning from bovine adrenal cortex, quantitative mRNA analysis, whole-cell patch clamp, cAMP analog and PKA inhibitor experiments","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 — mechanistic dissection of regulatory pathway with functional current measurements, single lab","pmids":["10913143"],"is_preprint":false},{"year":2001,"finding":"The N-terminus of Kv1.4 (and Kv1.5) binds to the internal spectrin repeats of alpha-actinin-2; this interaction is specific (not observed for Kv1.1, 1.2, or 1.3); the Kv1.5 binding region maps to residues 73–148 of the N-terminus; calmodulin does not affect this interaction.","method":"Yeast two-hybrid analysis, in vitro GST pulldown binding assays, N-terminal deletion mapping","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 3 — yeast two-hybrid plus in vitro pulldown, single lab, no in vivo validation","pmids":["11389904"],"is_preprint":false},{"year":2001,"finding":"The PDZ2 domain of PSD-95 is required for efficient clustering of Kv1.4; the position of PDZ2 in full-length PSD-95 is also prerequisite for normal cluster formation; PDZ1 dysfunction does not impair clustering, revealing that high-affinity PDZ2-ligand binding and correct multi-domain architecture both determine clustering efficiency.","method":"Site-directed mutagenesis of individual PDZ domains in full-length PSD-95, PDZ inversion constructs, COS-1 cell co-expression, immunofluorescence clustering assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — systematic mutagenesis with domain inversion constructs, multiple cell biology assays","pmids":["11723117"],"is_preprint":false},{"year":2001,"finding":"Riluzole irreversibly slows Kv1.4 inactivation (tau_i from 29 to 623 ms) by an oxidative, voltage-dependent mechanism: the effect is blocked by reducing agents (glutathione, DTT) and absent when applied at depolarized holding potentials, implicating a cysteine in the N-terminal inactivation domain as the target; riluzole also reversibly inhibits Kv1.4 current (IC50 = 70 μM) by a separate mechanism.","method":"Whole-cell patch clamp in bovine adrenal zona fasciculata cells, antioxidant and non-hydrolyzable ATP controls, holding potential manipulation","journal":"The Journal of pharmacology and experimental therapeutics","confidence":"Medium","confidence_rationale":"Tier 2 — mechanistic dissection with pharmacological controls, single lab","pmids":["11561084"],"is_preprint":false},{"year":2001,"finding":"Kv beta 2 enhances Kv1.4 current amplitude and accelerates inactivation; mutations in Kv beta 2 that disrupt the NADPH binding or catalytic site abolish the expression-enhancing effect but not the acceleration of inactivation, suggesting that the oxidoreductase activity of Kv beta 2 is required for correct processing/surface expression of Kv1.4 but not for modulation of inactivation kinetics.","method":"Xenopus oocyte co-expression, two-electrode voltage clamp, site-directed mutagenesis of Kvbeta2 NADPH-binding and catalytic sites, Western blot of Kv1.4 protein levels, yeast two-hybrid","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — mutagenesis of putative enzymatic site with functional dissection of two separate effects, protein-level validation","pmids":["11024060"],"is_preprint":false},{"year":2002,"finding":"C-type inactivation of Kv1.4 is sensitive to extracellular K+ (inhibited by elevated [K+]o), intracellular K+ (removal speeds C-type inactivation), and extracellular pH via histidine H508; a V561A mutation on the intracellular side of S6 inverts the C-type inactivation relationship with [K+]o; K532Y mutation slows C-type inactivation and abolishes pH dependence, demonstrating transmembrane communication between intracellular S6 and extracellular pore mouth in regulating inactivation.","method":"Xenopus oocyte two-electrode voltage clamp, N-terminal deletion mutant (fKv1.4ΔN), site-directed mutagenesis (V561A, K532Y, H508), ion substitution","journal":"American journal of physiology. Heart and circulatory physiology","confidence":"High","confidence_rationale":"Tier 1 — comprehensive mutagenesis with multiple ion-substitution experiments, mechanistic model validated","pmids":["12388308"],"is_preprint":false},{"year":2003,"finding":"N-glycosylation of Kv1.4 (but not Kv1.1) promotes protein stability and cell-surface trafficking; preventing glycosylation decreases Kv1.4 protein stability, causes intracellular retention, and reduces surface expression; a pore region determinant determines whether glycosylation positively or negatively affects trafficking, and this determinant can be transferred to chimeric Kv1.1 proteins.","method":"Glycosylation inhibitors and site-directed mutagenesis of glycosylation sites in Kv1.1 and Kv1.4, chimeric channel constructs, surface biotinylation, immunofluorescence, Western blot","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — chimeric channel approach identifies transferable determinant, multiple orthogonal assays","pmids":["14688283"],"is_preprint":false},{"year":2003,"finding":"PSD-95 palmitoylation is required to recruit Kv1.4 (but not Kv4.2) into lipid rafts; co-expression of PSD-95 increases raft-associated Kv1.4; deletion of the Kv1.4 C-terminal PSD-95 binding motif or substitution of palmitoylation-deficient PSD-95 eliminates raft recruitment, providing the first evidence that PSD-95 binding recruits Kv channels into lipid raft microdomains.","method":"Detergent-resistant membrane fractionation from rat brain, heterologous co-expression, lipid raft patching, immunostaining, deletion and palmitoylation mutants","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — native brain fractionation plus reconstitution with mutagenesis, multiple orthogonal approaches","pmids":["14559911"],"is_preprint":false},{"year":2003,"finding":"Kv1.4 cell-surface trafficking requires both a pore region determinant and a C-terminal VXXSL motif; removing VXXSL inhibits surface expression only when the Kv1.4 pore is present; the relevant subregion maps to a threonine residue in the deep pore; these two trafficking determinants act interdependently.","method":"Chimeric channel constructs between Kv1.4 and Kv1.1 pore regions, VXXSL deletion and truncation mutants, surface biotinylation, immunofluorescence in transfected cells","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 2 — systematic chimeric and deletion analysis with quantitative surface expression assay","pmids":["12901718"],"is_preprint":false},{"year":2003,"finding":"C-type inactivation in Kv1.4 involves allosteric coupling between the N-terminal inactivation ball or lipophilic compounds (like quinidine) and the cytoplasmic half of S6; binding of the N-terminal domain or quinidine to S6 shifts the channel into a conformation resembling the C-type inactivated state; the V561A mutation reduces affinity for both quinidine and the N-terminal domain, confirming S6 as part of the N-terminal binding site.","method":"Xenopus oocyte two-electrode voltage clamp, N-terminal deletion + V561A double mutant, quinidine pharmacology, varied [K+]o","journal":"The Journal of physiology","confidence":"High","confidence_rationale":"Tier 1 — mutagenesis with pharmacological probes identifies allosteric mechanism","pmids":["14608006"],"is_preprint":false},{"year":2003,"finding":"Arachidonic acid and other cis-unsaturated fatty acids inhibit Kv1.4 current and accelerate inactivation in native bovine adrenal zona fasciculata cells; lysophospholipids activate the co-expressed TREK-1 channel but do not affect Kv1.4; ETYA also inhibits Kv1.4, indicating direct lipid modulation independent of active AA metabolites.","method":"Whole-cell patch clamp in native bovine AZF cells, fatty acid/lysophospholipid application, ETYA control","journal":"The Journal of membrane biology","confidence":"Medium","confidence_rationale":"Tier 2 — direct pharmacological modulation in native cells, single lab","pmids":["14724761"],"is_preprint":false},{"year":2004,"finding":"An extracellular lysine residue K532 in Kv1.4 acts as a 'guard' regulating K+ access to the selectivity filter; mutation K532Y abolishes both K+ activation and C-type inactivation; protonation of H508 at acidic pH also abolishes K+ activation, indicating that extracellular charges regulate selectivity filter open probability.","method":"Xenopus oocyte two-electrode voltage clamp, site-directed mutagenesis (K532, H508), varied [K+]o and pH","journal":"Biophysical journal","confidence":"High","confidence_rationale":"Tier 1 — mutagenesis of specific residues with systematic ion and pH manipulation","pmids":["15454439"],"is_preprint":false},{"year":2005,"finding":"Neuronal transmission (via NMDA receptor Ca2+ influx) stimulates PKA phosphorylation of Kv1.4 at Ser229 in the T1 domain; glutamate, high K+, or K+ channel blockers increase Ser229 phosphorylation; TTX or Ca2+ depletion reduces it; Ser229Ala mutation enhances current density, indicating phosphorylation at this site reduces Kv1.4 channel activity.","method":"In vitro kinase assay, Western blot with phospho-Ser229-specific antibody in cultured rat cortical neurons, mutagenesis (Ser229Ala), pharmacological manipulation of neurotransmission","journal":"Journal of neurochemistry","confidence":"High","confidence_rationale":"Tier 1 — in vitro kinase assay plus site-specific antibody plus mutagenesis with functional current measurement","pmids":["16000151"],"is_preprint":false},{"year":2005,"finding":"EA1 mutations in KCNA1 (E325D, V404I, V408A, I177N) that line the pore or S1 segment of Kv1.1 alter fast inactivation of heteromeric Kv1.4-Kv1.1/Kvbeta1.1 and Kvbeta1.2 channels by decreasing rate and degree of N-type inactivation and accelerating recovery from inactivation; Kvbeta1.1/1.2 subunits regulate the proportion of wild-type Kv1.4-Kv1.1 channels available to open.","method":"Tandem-linked Kv1.4-Kv1.1 constructs expressed in Xenopus oocytes, two-electrode voltage clamp, EA1 point mutations","journal":"The European journal of neuroscience","confidence":"High","confidence_rationale":"Tier 1 — tandem constructs eliminate subunit stoichiometry ambiguity; systematic mutagenesis of EA1 mutations","pmids":["17156368"],"is_preprint":false},{"year":2006,"finding":"DPP10 modulates Kv1.4 inactivation similarly to its known effects on Kv4.3: co-expression causes faster time to peak current and negatively shifts half-inactivation potential; however, DPP10 slows rather than speeds recovery from inactivation in Kv1.4, demonstrating DPP10 as a general modulator of voltage-gated K+ channel inactivation acting on different inactivation states than KChIP2b.","method":"Xenopus oocyte co-expression, two-electrode voltage clamp, DPP10 transmembrane domain truncation mutants","journal":"American journal of physiology. Cell physiology","confidence":"Medium","confidence_rationale":"Tier 1 — direct reconstitution in Xenopus oocytes with systematic comparison, single lab","pmids":["16738002"],"is_preprint":false},{"year":2006,"finding":"EA1 mutation F184C in Kv1.1 sensitizes heteromeric Kv1.4-Kv1.1/Kvbeta1.1 channels to Zn2+: the complex has high-affinity (<10 μM) and low-affinity (<0.5 mM) Zn2+ binding sites; F184C decreases equilibrium dissociation constants for both sites, slows activation, increases time-to-peak, decreases N-type inactivation rate, and slows repriming compared with wild-type channels.","method":"Tandem Kv1.4-Kv1.1 constructs in Xenopus oocytes, two-electrode voltage clamp, Zn2+ dose-response, F184C mutation","journal":"American journal of physiology. Cell physiology","confidence":"High","confidence_rationale":"Tier 1 — tandem constructs with systematic Zn2+ concentration series and mutagenesis","pmids":["16956965"],"is_preprint":false},{"year":2007,"finding":"Ginsenoside Rg3 inhibits Kv1.4 channel current by interacting with residue Lys531; K531Y mutation abolishes the Rg3 effect; elevated [K+]o reduces Rg3 inhibition; Rg3 shifts K+ activation curve rightward and competes with TEA, with molecular docking showing hydrogen bonds between Rg3 and Lys531.","method":"Xenopus oocyte expression, two-electrode voltage clamp, site-directed mutagenesis (K531Y and others), K+ and TEA competition experiments, molecular docking","journal":"Molecular pharmacology","confidence":"Medium","confidence_rationale":"Tier 2 — mutagenesis identifies binding residue with pharmacological competition assays, single lab","pmids":["17959711"],"is_preprint":false},{"year":2007,"finding":"Kv1.4 is re-expressed in oligodendrocyte precursor cells (AN2-positive) and premyelinating oligodendrocytes during experimental autoimmune encephalomyelitis but not in mature oligodendrocytes or healthy adult spinal cord; Kv1.4-positive cells are actively proliferating and ensheathing naked axons, suggesting a role in oligodendroglial cell cycle progression during remyelination.","method":"Confocal immunofluorescence with cell-type markers, in vitro oligodendrocyte precursor culture, proliferation assays, ciliary neurotrophic factor knockout mice","journal":"The American journal of pathology","confidence":"Medium","confidence_rationale":"Tier 2 — cell-type-specific localization with proliferation correlation and genetic model, single lab","pmids":["17600124"],"is_preprint":false},{"year":2009,"finding":"Arachidonic acid (1 pM intracellular) inhibits Kv1.4-mediated IA by >50% and shifts voltage dependence of inactivation by -9 mV; Trolox C (antioxidant) slows AA effects on amplitude and shifts Kv1.4 activation by -32 mV, implicating an oxidative mechanism; these effects are direct on the channel alpha-subunit.","method":"Whole-cell voltage clamp of HEK293 cells transfected with Kv1.4 or Kv4.2 rat cDNA, intracellular AA application, Trolox C antioxidant controls","journal":"The European journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 — direct pharmacological modulation in heterologous system with antioxidant controls, single lab","pmids":["19453640"],"is_preprint":false},{"year":2010,"finding":"In cortical pyramidal neurons, Kv1.4, Kv4.2, and Kv4.3 encode distinct components of macroscopic IA; in cells lacking both Kv4.2 and Kv4.3, Kv1.4 encodes a minor but ubiquitous IA component; loss of individual subunits causes Kv alpha-subunit-specific electrical remodeling.","method":"Single and double knockout mice (Kv1.4-/-, Kv4.2-/-, Kv4.3-/-), whole-cell patch clamp of cortical pyramidal neurons, 4-AP pharmacology","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 — clean genetic dissection with double knockouts and pharmacological tools, replicated across genotypes","pmids":["20371829"],"is_preprint":false},{"year":2011,"finding":"Kv1.4 and Kv1.5 associate with native Kv1 heteromultimers in human CNS; sequential immunoprecipitation identifies a Kv1.3/1.4/1.1/1.2 tetramer in grey matter, Kv1.1/1.4 dimers in white matter and spinal cord, and apparent Kv1.4 homotetramers in all CNS regions, with Kvbeta1.1 coprecipitating with all alpha subunits in white matter.","method":"Sequential immunoprecipitation from human autopsy tissue (cerebral grey/white matter, spinal cord) with subunit-specific antibodies, immunoblotting","journal":"Journal of neurochemistry","confidence":"High","confidence_rationale":"Tier 2 — sequential immunoprecipitation from native human tissue, comprehensive subunit mapping","pmids":["10428084"],"is_preprint":false},{"year":2011,"finding":"A model of Kv1.4 inactivation demonstrates that N- and C-type inactivation are coupled through direct transitions between N- and C-type inactivated states; C-type inactivation begins at lower-voltage pre-activated states while N-type is coupled to the open state; C-type inactivation is the rate-limiting step for recovery, and a model with only distinct inactivated states without cross-transitions cannot reproduce experimental data.","method":"Two-electrode voltage clamp of Kv1.4 and Kv1.4ΔN in Xenopus oocytes, K532Y mutation, computational Markov chain modeling constrained by experimental data","journal":"Biophysical journal","confidence":"High","confidence_rationale":"Tier 1 — experimental data + validated computational model with mutagenesis constraints","pmids":["21190652"],"is_preprint":false},{"year":2013,"finding":"Spinal cord injury in rats reduces Kv1.4 protein and mRNA expression in bladder afferent neurons, accompanied by decreased A-type K+ current density and a hyperpolarizing shift in KA inactivation, resulting in increased nociceptor excitability with lower spike thresholds and tonic firing.","method":"Whole-cell patch clamp of dissociated L6-S1 DRG neurons, immunohistochemistry, real-time PCR, spinal transection model","journal":"The Journal of urology","confidence":"Medium","confidence_rationale":"Tier 2 — correlates Kv1.4 expression with electrophysiological excitability changes in spinal injury model, single lab","pmids":["23896350"],"is_preprint":false},{"year":2014,"finding":"Nociceptor-specific deletion of gp130 (IL-6 signal transducer) in SNS-gp130-/- mice increases A-type K+ currents and Kcna4 (Kv1.4) mRNA levels in sensory neurons, reducing excitability, suggesting IL-6/gp130 signaling normally suppresses Kv1.4 expression and thereby promotes nociceptor excitability.","method":"Conditional knockout mice, whole-cell patch clamp, TaqMan RT-PCR for Kcna4 and other ion channel mRNAs, action potential recording","journal":"Pflugers Archiv","confidence":"Medium","confidence_rationale":"Tier 2 — conditional knockout with direct electrophysiological and mRNA measurement, single lab","pmids":["24463703"],"is_preprint":false},{"year":2015,"finding":"Loss of Kv1.4 (Kcna4-/-) shortens circadian period in SCN firing and locomotor activity by ~0.5 h and reduces PER2 expression period in SCN explants; combined loss of Kv1.4 and Kv4.2 advances daily activity onset by ~1.8 h in a light cycle, demonstrating that IA channels encoded by Kv1.4 feed back onto molecular clock (PER2) expression.","method":"Kv1.4-/- and Kv4.2-/- knockout mice crossed with Per2Luc reporter mice, SCN explant bioluminescence imaging, wheel-running locomotor activity recording","journal":"Journal of biological rhythms","confidence":"High","confidence_rationale":"Tier 2 — genetic knockout with PER2::LUC molecular clock readout, replicated in multiple genotypes","pmids":["26152125"],"is_preprint":false},{"year":2016,"finding":"A missense variant p.Arg89Gln in KCNA4 causes a novel autosomal recessive syndrome with congenital cataract, striatal thinning, intellectual disability, and ADHD; the R89Q mutant produces significantly lower current amplitude than wild-type in Xenopus oocytes, and co-expression of wild-type and mutant results in intermediate current, indicating loss-of-function; KCNA4 mRNA is expressed in mouse brain, lens, and retina, and Kv1.4 co-localizes with cholinergic amacrine and rod bipolar cells.","method":"SNP arrays, autozygosity mapping, whole-exome sequencing, two-electrode voltage clamp in Xenopus oocytes, RT-PCR, immunohistochemistry","journal":"Journal of medical genetics","confidence":"High","confidence_rationale":"Tier 2 — functional expression of disease variant with electrophysiological characterization, confirmed in multiple family members","pmids":["27582084"],"is_preprint":false},{"year":2019,"finding":"IL-6 downregulates Kv1.4 expression in dorsal root ganglion nociceptors via gp130/IL-6 receptor signaling, causing muscle hyperalgesia in a rat vibration model; antisense knockdown of Kv1.4 in DRG mimics vibration-induced muscle hyperalgesia; anti-IL-6 antibody attenuates both hyperalgesia and Kv1.4 downregulation.","method":"Rat hindlimb vibration model, local neutralizing anti-IL-6 injection, Kv1.4 antisense knockdown in DRG, gp130 knockdown, immunohistochemistry, behavioral pain testing","journal":"Pain","confidence":"High","confidence_rationale":"Tier 2 — antisense knockdown phenocopies disease model; antibody rescue; receptor subunit knockdown epistasis, single lab","pmids":["31335655"],"is_preprint":false}],"current_model":"KCNA4 (Kv1.4) is a voltage-gated A-type K+ channel that undergoes rapid N-type inactivation (ball-and-chain mechanism from the N-terminus) coupled to slower C-type inactivation at the extracellular pore (involving residues H508 and K532), with C-type inactivation serving as the rate-limiting step for recovery; channel gating is regulated by CaMKII phosphorylation of N-terminal residues (slowing inactivation) and PKA phosphorylation at Ser229 (reducing current density), and by redox modification of N-terminal cysteines; Kv1.4 traffics to the cell surface via a pore-region determinant and C-terminal VXXSL motif, is clustered and stabilized at the surface by PSD-95 (via PDZ2-mediated binding to the C-terminal -ETDV motif) and recruited into lipid rafts through palmitoylated PSD-95; Kv beta subunits modulate inactivation kinetics and surface expression through interactions requiring NADPH-binding activity; Kv1.4 forms heteromultimers with other Kv1 subunits in native CNS tissue, encodes the slow-recovering Ito in cardiac and septal myocytes, is localized presynaptically in hippocampal axons where it regulates LTP, and its loss-of-function causes a human syndrome of striatal abnormality, congenital cataract, and intellectual disability."},"narrative":{"teleology":[{"year":1991,"claim":"Molecular cloning and functional expression established that KCNA4 encodes a rapidly inactivating, 4-AP-sensitive voltage-gated K+ channel, defining its biophysical identity within the Shaker family.","evidence":"cDNA cloning from human ventricle, Xenopus oocyte two-electrode voltage clamp","pmids":["2001794","1986382"],"confidence":"High","gaps":["No structural model of the full-length channel","Subunit stoichiometry of native channels unknown"]},{"year":1993,"claim":"Demonstration that a single Kv1.4 subunit confers rapid inactivation on heteromeric Kv1.1/1.2/1.5 complexes explained how native A-type currents with intermediate kinetics arise from mixed-subunit assemblies.","evidence":"Co-injection of cRNAs in Xenopus oocytes with functional voltage clamp characterization","pmids":["8495559","8661510"],"confidence":"High","gaps":["Native subunit stoichiometry not determined at single-channel level","Heteromer assembly rules beyond pairwise not established"]},{"year":1995,"claim":"Dissection of inactivation gating revealed that N-type (ball-and-chain) and C-type (pore) inactivation are coupled, with C-type inactivation as the rate-limiting step for recovery, resolving a longstanding question about why Kv1.4 recovery is much slower than N-type inactivation alone predicts.","evidence":"N-terminal deletion mutagenesis and voltage-sensor mutations in Xenopus oocytes","pmids":["8788936"],"confidence":"High","gaps":["Structural basis of C-type inactivation at the pore not visualized","Coupling mechanism between N-type ball and C-type gate at atomic resolution unknown"]},{"year":1995,"claim":"PSD-95 was identified as the scaffolding partner that clusters Kv1.4 at the cell surface via PDZ-domain binding to the channel's C-terminal ETDV motif, establishing a paradigm for synaptic K+ channel localization.","evidence":"Yeast two-hybrid, co-immunoprecipitation, heterologous cell co-expression, and immunofluorescence clustering","pmids":["7477295","8938729"],"confidence":"High","gaps":["In vivo disruption of PSD-95–Kv1.4 interaction not performed genetically","Whether PSD-95 clustering alters channel biophysics in neurons unresolved"]},{"year":1997,"claim":"CaMKII phosphorylation of N-terminal residues was shown to slow inactivation and accelerate recovery, while calcineurin-mediated dephosphorylation restores fast inactivation, establishing Ca²⁺-dependent bidirectional regulation of Kv1.4 gating.","evidence":"Direct enzyme application to Kv1.4-expressing Xenopus oocytes with voltage clamp","pmids":["9133364"],"confidence":"High","gaps":["Exact phosphorylation site(s) not identified by mass spectrometry","In vivo physiological context of CaMKII regulation not tested"]},{"year":1998,"claim":"Ultrastructural localization placed Kv1.4 at presynaptic axons and boutons in hippocampus, and antisense knockdown eliminated both early- and late-phase LTP at CA1, establishing a presynaptic role in synaptic plasticity.","evidence":"Immunogold electron microscopy and in vivo antisense knockdown with electrophysiology","pmids":["9437018","9844011"],"confidence":"High","gaps":["Antisense approach lacks genetic specificity; conditional knockout confirmation absent","Mechanism by which presynaptic Kv1.4 regulates LTP induction not defined"]},{"year":1998,"claim":"Palmitoylation of PSD-95 N-terminal cysteines was found to be required for in vivo interaction with Kv1.4 and subsequent lipid raft recruitment, linking post-translational modification of the scaffold to channel microdomain targeting.","evidence":"Metabolic [³H]palmitate labeling, Cys3/5 mutagenesis, co-immunoprecipitation, later confirmed by raft fractionation from rat brain","pmids":["9459448","14559911"],"confidence":"High","gaps":["Whether raft localization affects Kv1.4 single-channel conductance or open probability not tested","Enzyme(s) catalyzing PSD-95 palmitoylation not identified in these studies"]},{"year":2000,"claim":"Identification of H508 and K532 as extracellular pore residues governing pH-sensitive C-type inactivation, and V561 as the intracellular S6 residue allosterically coupled to the outer pore, defined the transmembrane communication pathway regulating recovery kinetics.","evidence":"Site-directed mutagenesis with ion-substitution and pH experiments in Xenopus oocytes","pmids":["10896716","12388308","14608006"],"confidence":"High","gaps":["No crystal or cryo-EM structure of Kv1.4 to validate structural interpretation","Role of these residues in native cardiac or neuronal context not confirmed"]},{"year":2000,"claim":"Combined genetic elimination of Kv4.2-mediated Ito,f and Kv1.4-mediated Ito,s in mice caused severe arrhythmias (QT prolongation, VT), proving that Kv1.4 encodes the slow-recovering transient outward current and that both Ito components are essential for cardiac repolarization.","evidence":"Kv4.2W362F transgenic × Kv1.4−/− knockout mice with telemetric ECG and patch clamp","pmids":["10884375"],"confidence":"High","gaps":["Human cardiac relevance not directly tested; species differences in Ito composition exist","Compensatory remodeling in double-mutant mice not fully characterized"]},{"year":2001,"claim":"Kvβ2 was shown to enhance Kv1.4 surface expression through an NADPH-binding-dependent mechanism distinct from its kinetic modulation of inactivation, separating the β-subunit's oxidoreductase-like chaperone function from its direct gating effects.","evidence":"Mutagenesis of Kvβ2 NADPH-binding and catalytic sites with co-expression in oocytes and Western blot of protein levels","pmids":["11024060"],"confidence":"High","gaps":["Whether Kvβ2 acts as a true oxidoreductase on Kv1.4 or functions as a chaperone through NADPH-induced conformation unknown","No in vivo trafficking assay"]},{"year":2003,"claim":"Identification of a pore-region determinant and a C-terminal VXXSL motif as interdependent trafficking signals resolved how Kv1.4 achieves efficient cell-surface expression while the highly homologous Kv1.1 is retained in the ER.","evidence":"Chimeric Kv1.4/Kv1.1 channels, VXXSL deletion, surface biotinylation","pmids":["14688283","12901718"],"confidence":"High","gaps":["Coat protein or adaptor recognizing VXXSL not identified","Contribution of glycosylation versus VXXSL in native neurons not dissected"]},{"year":2005,"claim":"PKA phosphorylation at Ser229 in the T1 domain was identified as a neuronal-activity-dependent mechanism reducing Kv1.4 current density, adding a second kinase-based regulatory axis complementary to CaMKII-mediated gating modulation.","evidence":"Phospho-Ser229-specific antibody in cultured cortical neurons, in vitro kinase assay, S229A mutagenesis with electrophysiology","pmids":["16000151"],"confidence":"High","gaps":["Whether Ser229 phosphorylation affects surface expression, open probability, or both not distinguished","Downstream physiological consequence (e.g. firing rate change) not measured"]},{"year":2011,"claim":"Sequential immunoprecipitation from human CNS tissue mapped native Kv1.4-containing heteromeric complexes — including Kv1.3/1.4/1.1/1.2 tetramers in grey matter and Kv1.1/1.4 dimers in white matter — providing the first systematic view of Kv1.4 heteromeric composition in the human brain.","evidence":"Sequential immunoprecipitation from human autopsy tissue with subunit-specific antibodies","pmids":["10428084"],"confidence":"High","gaps":["Stoichiometry within individual tetramers not determined","Functional properties of specific native heteromers not reconstituted"]},{"year":2015,"claim":"Kv1.4 knockout shortened circadian period by ~0.5 h and reduced PER2 expression period in SCN, revealing an unexpected feedback from membrane excitability (IA) onto the molecular clock.","evidence":"Kcna4−/− mice crossed with PER2::LUC reporter, SCN explant bioluminescence, wheel-running activity","pmids":["26152125"],"confidence":"High","gaps":["Signal transduction pathway from Kv1.4 current to PER2 transcription not identified","Whether this is a direct cell-autonomous effect or network-level phenomenon not resolved"]},{"year":2016,"claim":"The p.Arg89Gln loss-of-function variant was identified as the cause of an autosomal recessive syndrome of congenital cataract, striatal thinning, and intellectual disability, establishing the first human Mendelian disease linked to KCNA4.","evidence":"Autozygosity mapping, whole-exome sequencing, functional expression of R89Q in Xenopus oocytes showing reduced current","pmids":["27582084"],"confidence":"High","gaps":["Only one family reported; independent replication in additional families not yet published","Mechanism linking Kv1.4 loss-of-function to cataract formation not elucidated"]},{"year":2019,"claim":"IL-6/gp130 signaling was shown to downregulate Kv1.4 in nociceptors, and Kv1.4 antisense knockdown phenocopied vibration-induced hyperalgesia, mechanistically linking cytokine-driven Kv1.4 suppression to pain sensitization.","evidence":"Rat vibration model with anti-IL-6 antibody rescue, Kv1.4 antisense knockdown in DRG, gp130 conditional knockdown","pmids":["31335655"],"confidence":"High","gaps":["Whether Kv1.4 downregulation is transcriptional or post-transcriptional not determined","Relevance to chronic pain syndromes in humans not established"]},{"year":null,"claim":"No high-resolution structure of Kv1.4 exists, the precise mechanism linking N-terminal ball binding at S6 to outer-pore C-type inactivation conformational change remains structurally unresolved, and the signaling pathway by which Kv1.4 current feeds back onto PER2 transcription in the SCN is unknown.","evidence":"","pmids":[],"confidence":"High","gaps":["No cryo-EM or crystal structure of Kv1.4 homomeric or heteromeric channel","Structural basis of N-type/C-type inactivation coupling not visualized","Molecular link between Kv1.4-mediated IA and circadian clock gene expression unidentified"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005215","term_label":"transporter activity","supporting_discovery_ids":[0,1,2]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[10,37]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[6,7,21,23,31,33]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[12,21]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[15]}],"pathway":[{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[0,2,15,18,44,45]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[10,37,48,51]},{"term_id":"R-HSA-382551","term_label":"Transport of small molecules","supporting_discovery_ids":[0,1,2,20,24]},{"term_id":"R-HSA-9909396","term_label":"Circadian clock","supporting_discovery_ids":[49]}],"complexes":["Kv1 heteromultimeric channel complex","Kv1.4/Kvβ complex"],"partners":["DLG4","DLG1","KCNAB1","KCNAB2","KCNAB3","KCNA1","KCNA2","ACTN2"],"other_free_text":[]},"mechanistic_narrative":"KCNA4 (Kv1.4) is a voltage-gated potassium channel that conducts a rapidly inactivating A-type K+ current, playing key roles in cardiac repolarization (slow-recovering Ito,s), presynaptic regulation of hippocampal LTP, nociceptor excitability, and circadian clock period modulation [PMID:2001794, PMID:10330244, PMID:9844011, PMID:26152125]. The channel undergoes fast N-type inactivation via a ball-and-chain mechanism at the N-terminus coupled to slower C-type inactivation at the extracellular pore (involving H508 and K532), with C-type inactivation serving as the rate-limiting step for recovery; these two inactivation processes are allosterically linked through the cytoplasmic S6 segment [PMID:8788936, PMID:12388308, PMID:14608006]. Channel gating is dynamically regulated by CaMKII/calcineurin phosphorylation of N-terminal residues, PKA phosphorylation at Ser229, and redox modification of N-terminal cysteines, while surface expression and clustering depend on PSD-95 PDZ2-mediated binding to the C-terminal ETDV motif, palmitoylation-dependent lipid raft recruitment, Kvβ subunit-assisted trafficking, and a pore-region/VXXSL dual determinant [PMID:9133364, PMID:16000151, PMID:8584439, PMID:7477295, PMID:14559911, PMID:11024060, PMID:12901718]. Loss-of-function mutation p.Arg89Gln causes an autosomal recessive syndrome of congenital cataract, striatal abnormality, and intellectual disability [PMID:27582084]."},"prefetch_data":{"uniprot":{"accession":"P22459","full_name":"Potassium voltage-gated channel subfamily A member 4","aliases":["HPCN2","Voltage-gated K(+) channel HuKII","Voltage-gated potassium channel HBK4","Voltage-gated potassium channel HK1","Voltage-gated potassium channel subunit Kv1.4"],"length_aa":653,"mass_kda":73.3,"function":"Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes. Forms tetrameric potassium-selective channels through which potassium ions pass in accordance with their electrochemical gradient. The channel alternates between opened and closed conformations in response to the voltage difference across the membrane (PubMed:19912772, PubMed:8495559). Can form functional homotetrameric channels and heterotetrameric channels that contain variable proportions of KCNA1, KCNA2, KCNA4, KCNA5, and possibly other family members as well; channel properties depend on the type of alpha subunits that are part of the channel (PubMed:8495559). Channel properties are modulated by cytoplasmic beta subunits that regulate the subcellular location of the alpha subunits and promote rapid inactivation. In vivo, membranes probably contain a mixture of heteromeric potassium channel complexes, making it difficult to assign currents observed in intact tissues to any particular potassium channel family member. Homotetrameric KCNA4 forms a potassium channel that opens in response to membrane depolarization, followed by rapid spontaneous channel closure (PubMed:19912772, PubMed:8495559). Likewise, a heterotetrameric channel formed by KCNA1 and KCNA4 shows rapid inactivation (PubMed:17156368)","subcellular_location":"Cell membrane; Cell projection, axon","url":"https://www.uniprot.org/uniprotkb/P22459/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/KCNA4","classification":"Not Classified","n_dependent_lines":7,"n_total_lines":1208,"dependency_fraction":0.005794701986754967},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"PRKACA","stoichiometry":0.2},{"gene":"TOMM20A","stoichiometry":0.2},{"gene":"VDAC1","stoichiometry":0.2},{"gene":"VDAC3","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/KCNA4","total_profiled":1310},"omim":[{"mim_id":"619295","title":"ZDHHC PALMITOYLTRANSFERASE 14; ZDHHC14","url":"https://www.omim.org/entry/619295"},{"mim_id":"618284","title":"MICROCEPHALY, CATARACTS, IMPAIRED INTELLECTUAL DEVELOPMENT, AND DYSTONIA WITH ABNORMAL STRIATUM; MCIDDS","url":"https://www.omim.org/entry/618284"},{"mim_id":"605445","title":"DISCS LARGE-ASSOCIATED PROTEIN 1; DLGAP1","url":"https://www.omim.org/entry/605445"},{"mim_id":"604111","title":"POTASSIUM CHANNEL, VOLTAGE-GATED, SHAKER-RELATED SUBFAMILY, BETA MEMBER 3; KCNAB3","url":"https://www.omim.org/entry/604111"},{"mim_id":"603583","title":"DISCS LARGE MAGUK SCAFFOLD PROTEIN 2; DLG2","url":"https://www.omim.org/entry/603583"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"adrenal gland","ntpm":5.8},{"tissue":"brain","ntpm":7.9}],"url":"https://www.proteinatlas.org/search/KCNA4"},"hgnc":{"alias_symbol":["Kv1.4","HK1","HPCN2","PCN2"],"prev_symbol":["KCNA4L"]},"alphafold":{"accession":"P22459","domains":[{"cath_id":"3.30.710.10","chopping":"176-272","consensus_level":"high","plddt":94.8719,"start":176,"end":272},{"cath_id":"1.20.120.350","chopping":"287-341_368-424_438-460","consensus_level":"high","plddt":87.396,"start":287,"end":460},{"cath_id":"1.10.287.70","chopping":"466-578","consensus_level":"high","plddt":92.3428,"start":466,"end":578}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P22459","model_url":"https://alphafold.ebi.ac.uk/files/AF-P22459-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P22459-F1-predicted_aligned_error_v6.png","plddt_mean":69.56},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=KCNA4","jax_strain_url":"https://www.jax.org/strain/search?query=KCNA4"},"sequence":{"accession":"P22459","fasta_url":"https://rest.uniprot.org/uniprotkb/P22459.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P22459/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P22459"}},"corpus_meta":[{"pmid":"26119735","id":"PMC_26119735","title":"mTORC1-Induced HK1-Dependent Glycolysis Regulates NLRP3 Inflammasome Activation.","date":"2015","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/26119735","citation_count":327,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9459448","id":"PMC_9459448","title":"N-terminal palmitoylation of PSD-95 regulates association with cell membranes and interaction with K+ channel Kv1.4.","date":"1998","source":"Neuron","url":"https://pubmed.ncbi.nlm.nih.gov/9459448","citation_count":257,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"6259064","id":"PMC_6259064","title":"Establishment of a cell line (NPC/HK1) from a differentiated squamous carcinoma of the nasopharynx.","date":"1980","source":"International journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/6259064","citation_count":210,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10884375","id":"PMC_10884375","title":"Functional consequences of elimination of i(to,f) and i(to,s): early afterdepolarizations, atrioventricular block, and ventricular arrhythmias in mice lacking Kv1.4 and expressing a dominant-negative Kv4 alpha subunit.","date":"2000","source":"Circulation research","url":"https://pubmed.ncbi.nlm.nih.gov/10884375","citation_count":140,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9133364","id":"PMC_9133364","title":"Frequency-dependent inactivation of mammalian A-type K+ channel KV1.4 regulated by Ca2+/calmodulin-dependent protein kinase.","date":"1997","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/9133364","citation_count":137,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9437018","id":"PMC_9437018","title":"Presynaptic localization of Kv1.4-containing A-type potassium channels near excitatory synapses in the hippocampus.","date":"1998","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/9437018","citation_count":112,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"36192599","id":"PMC_36192599","title":"HK1 from hepatic stellate cell-derived extracellular vesicles promotes progression of hepatocellular carcinoma.","date":"2022","source":"Nature metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/36192599","citation_count":103,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"8788936","id":"PMC_8788936","title":"C-type inactivation controls recovery in a fast inactivating cardiac K+ channel (Kv1.4) expressed in Xenopus oocytes.","date":"1995","source":"The Journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/8788936","citation_count":101,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10625685","id":"PMC_10625685","title":"Internalization of the Kv1.4 potassium channel is suppressed by clustering interactions with PSD-95.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10625685","citation_count":94,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"14688283","id":"PMC_14688283","title":"Glycosylation affects the protein stability and cell surface expression of Kv1.4 but Not Kv1.1 potassium channels. A pore region determinant dictates the effect of glycosylation on trafficking.","date":"2003","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/14688283","citation_count":94,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9547391","id":"PMC_9547391","title":"The transient outward current in mice lacking the potassium channel gene Kv1.4.","date":"1998","source":"The Journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/9547391","citation_count":92,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9508088","id":"PMC_9508088","title":"Mouse spermatogenic cell-specific type 1 hexokinase (mHk1-s) transcripts are expressed by alternative splicing from the mHk1 gene and the HK1-S protein is localized mainly in the sperm tail.","date":"1998","source":"Molecular reproduction and development","url":"https://pubmed.ncbi.nlm.nih.gov/9508088","citation_count":92,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"14559911","id":"PMC_14559911","title":"Differential recruitment of Kv1.4 and Kv4.2 to lipid rafts by PSD-95.","date":"2003","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/14559911","citation_count":90,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10330244","id":"PMC_10330244","title":"Regional contributions of Kv1.4, Kv4.2, and Kv4.3 to transient outward K+ current in rat ventricle.","date":"1999","source":"The American journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/10330244","citation_count":88,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"21606185","id":"PMC_21606185","title":"The hybrid histidine kinase Hk1 is part of a two-component system that is essential for survival of Borrelia burgdorferi in feeding Ixodes scapularis ticks.","date":"2011","source":"Infection and immunity","url":"https://pubmed.ncbi.nlm.nih.gov/21606185","citation_count":80,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"25296002","id":"PMC_25296002","title":"Cr(VI) reduction and Cr(III) immobilization by Acinetobacter sp. HK-1 with the assistance of a novel quinone/graphene oxide composite.","date":"2014","source":"Environmental science & technology","url":"https://pubmed.ncbi.nlm.nih.gov/25296002","citation_count":80,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"19096518","id":"PMC_19096518","title":"Novel association of HK1 with glycated hemoglobin in a non-diabetic population: a genome-wide evaluation of 14,618 participants in the Women's Genome Health Study.","date":"2008","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/19096518","citation_count":77,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"7691883","id":"PMC_7691883","title":"Shaker-related potassium channel, Kv1.4, mRNA regulation in cultured rat heart myocytes and differential expression of Kv1.4 and Kv1.5 genes in myocardial development and hypertrophy.","date":"1993","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/7691883","citation_count":77,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9867876","id":"PMC_9867876","title":"Requirement of N-terminal cysteines of PSD-95 for PSD-95 multimerization and ternary complex formation, but not for binding to potassium channel Kv1.4.","date":"1999","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9867876","citation_count":72,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9844011","id":"PMC_9844011","title":"Memory and long-term potentiation (LTP) dissociated: normal spatial memory despite CA1 LTP elimination with Kv1.4 antisense.","date":"1998","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/9844011","citation_count":70,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12842130","id":"PMC_12842130","title":"Centrally administered hemokinin-1 (HK-1), a neurokinin NK1 receptor agonist, produces substance P-like behavioral effects in mice and gerbils.","date":"2003","source":"Neuropharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/12842130","citation_count":69,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"16182377","id":"PMC_16182377","title":"Novel autoantibodies to a voltage-gated potassium channel Kv1.4 in a severe form of myasthenia gravis.","date":"2005","source":"Journal of neuroimmunology","url":"https://pubmed.ncbi.nlm.nih.gov/16182377","citation_count":66,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"33253911","id":"PMC_33253911","title":"BDNF corrects NLRP3 inflammasome-induced pyroptosis and glucose metabolism reprogramming through KLF2/HK1 pathway in vascular endothelial cells.","date":"2020","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/33253911","citation_count":61,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"20371829","id":"PMC_20371829","title":"Molecular dissection of I(A) in cortical pyramidal neurons reveals three distinct components encoded by Kv4.2, Kv4.3, and Kv1.4 alpha-subunits.","date":"2010","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/20371829","citation_count":57,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"25795449","id":"PMC_25795449","title":"Interaction of Cr(VI) reduction and denitrification by strain Pseudomonas aeruginosa PCN-2 under aerobic conditions.","date":"2015","source":"Bioresource technology","url":"https://pubmed.ncbi.nlm.nih.gov/25795449","citation_count":57,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"25190649","id":"PMC_25190649","title":"A dominant mutation in hexokinase 1 (HK1) causes retinitis pigmentosa.","date":"2014","source":"Investigative ophthalmology & visual science","url":"https://pubmed.ncbi.nlm.nih.gov/25190649","citation_count":55,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11389904","id":"PMC_11389904","title":"A discrete amino terminal domain of Kv1.5 and Kv1.4 potassium channels interacts with the spectrin repeats of alpha-actinin-2.","date":"2001","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/11389904","citation_count":54,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"23859901","id":"PMC_23859901","title":"Dominant form of congenital hyperinsulinism maps to HK1 region on 10q.","date":"2013","source":"Hormone research in paediatrics","url":"https://pubmed.ncbi.nlm.nih.gov/23859901","citation_count":52,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"29054762","id":"PMC_29054762","title":"MiR-34a, as a suppressor, enhance the susceptibility of gastric cancer cell to luteolin by directly targeting HK1.","date":"2017","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/29054762","citation_count":50,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"17156368","id":"PMC_17156368","title":"Episodic ataxia type 1 mutations in the KCNA1 gene impair the fast inactivation properties of the human potassium channels Kv1.4-1.1/Kvbeta1.1 and Kv1.4-1.1/Kvbeta1.2.","date":"2006","source":"The European journal of neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/17156368","citation_count":50,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"30885978","id":"PMC_30885978","title":"An HK2 Antisense Oligonucleotide Induces Synthetic Lethality in HK1-HK2+ Multiple Myeloma.","date":"2019","source":"Cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/30885978","citation_count":49,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"32035153","id":"PMC_32035153","title":"Anti-inflammation activity of exopolysaccharides produced by a medicinal fungus Cordyceps sinensis Cs-HK1 in cell and animal models.","date":"2020","source":"International journal of biological macromolecules","url":"https://pubmed.ncbi.nlm.nih.gov/32035153","citation_count":49,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9368023","id":"PMC_9368023","title":"Serpin-derived peptide substrates for investigating the substrate specificity of human tissue kallikreins hK1 and hK2.","date":"1997","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9368023","citation_count":47,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"22167224","id":"PMC_22167224","title":"Anti-voltage-gated potassium channel Kv1.4 antibodies in myasthenia gravis.","date":"2011","source":"Journal of neurology","url":"https://pubmed.ncbi.nlm.nih.gov/22167224","citation_count":46,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11723117","id":"PMC_11723117","title":"Ligand binding of the second PDZ domain regulates clustering of PSD-95 with the Kv1.4 potassium channel.","date":"2001","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11723117","citation_count":46,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10896716","id":"PMC_10896716","title":"Inhibition of the K+ channel kv1.4 by acidosis: protonation of an extracellular histidine slows the recovery from N-type inactivation.","date":"2000","source":"The Journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/10896716","citation_count":44,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"7631872","id":"PMC_7631872","title":"Time- and voltage-dependent modulation of a Kv1.4 channel by a beta-subunit (Kv beta 3) cloned from ferret ventricle.","date":"1995","source":"The American journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/7631872","citation_count":41,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"36333503","id":"PMC_36333503","title":"Non-coding variants disrupting a tissue-specific regulatory element in HK1 cause congenital hyperinsulinism.","date":"2022","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/36333503","citation_count":40,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"23896350","id":"PMC_23896350","title":"Hyperexcitability of bladder afferent neurons associated with reduction of Kv1.4 α-subunit in rats with spinal cord injury.","date":"2013","source":"The Journal of urology","url":"https://pubmed.ncbi.nlm.nih.gov/23896350","citation_count":40,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11561084","id":"PMC_11561084","title":"Neuroprotective agent riluzole dramatically slows inactivation of Kv1.4 potassium channels by a voltage-dependent oxidative mechanism.","date":"2001","source":"The Journal of pharmacology and experimental therapeutics","url":"https://pubmed.ncbi.nlm.nih.gov/11561084","citation_count":39,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9710812","id":"PMC_9710812","title":"Regulation of Kv4.2 and Kv1.4 K+ channel expression by myocardial hypertrophic factors in cultured newborn rat ventricular cells.","date":"1998","source":"Journal of molecular and cellular cardiology","url":"https://pubmed.ncbi.nlm.nih.gov/9710812","citation_count":39,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"14724761","id":"PMC_14724761","title":"Modulation of native TREK-1 and Kv1.4 K+ channels by polyunsaturated fatty acids and lysophospholipids.","date":"2003","source":"The Journal of membrane biology","url":"https://pubmed.ncbi.nlm.nih.gov/14724761","citation_count":38,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"25316723","id":"PMC_25316723","title":"A missense mutation in HK1 leads to autosomal dominant retinitis pigmentosa.","date":"2014","source":"Investigative ophthalmology & visual science","url":"https://pubmed.ncbi.nlm.nih.gov/25316723","citation_count":37,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"8020965","id":"PMC_8020965","title":"Genomic organization, nucleotide sequence, biophysical properties, and localization of the voltage-gated K+ channel gene KCNA4/Kv1.4 to mouse chromosome 2/human 11p14 and mapping of KCNC1/Kv3.1 to mouse 7/human 11p14.3-p15.2 and KCNA1/Kv1.1 to human 12p13.","date":"1994","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/8020965","citation_count":36,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9334228","id":"PMC_9334228","title":"A cellular model for long QT syndrome. Trapping of heteromultimeric complexes consisting of truncated Kv1.1 potassium channel polypeptides and native Kv1.4 and Kv1.5 channels in the endoplasmic reticulum.","date":"1997","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9334228","citation_count":36,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"8584439","id":"PMC_8584439","title":"Cysteine-modifying reagents alter the gating of the rat cloned potassium channel Kv1.4.","date":"1996","source":"Pflugers Archiv : European journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/8584439","citation_count":33,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12788813","id":"PMC_12788813","title":"Dihydropyridine Ca2+ channel antagonists and agonists block Kv4.2, Kv4.3 and Kv1.4 K+ channels expressed in HEK293 cells.","date":"2003","source":"British journal of pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/12788813","citation_count":33,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"28105937","id":"PMC_28105937","title":"Effect of lentivirus-mediated shRNA inactivation of HK1, HK2, and HK3 genes in colorectal cancer and melanoma cells.","date":"2016","source":"BMC genetics","url":"https://pubmed.ncbi.nlm.nih.gov/28105937","citation_count":32,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"7589202","id":"PMC_7589202","title":"Antiarrhythmic and bradycardic drugs inhibit currents of cloned K+ channels, KV1.2 and KV1.4.","date":"1995","source":"European journal of pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/7589202","citation_count":32,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"25974126","id":"PMC_25974126","title":"NF-κB p65 Subunit Is Modulated by Latent Transforming Growth Factor-β Binding Protein 2 (LTBP2) in Nasopharyngeal Carcinoma HONE1 and HK1 Cells.","date":"2015","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/25974126","citation_count":31,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"8661510","id":"PMC_8661510","title":"N-type inactivation in the mammalian Shaker K+ channel Kv1.4.","date":"1996","source":"The Journal of membrane biology","url":"https://pubmed.ncbi.nlm.nih.gov/8661510","citation_count":31,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"16738002","id":"PMC_16738002","title":"DPP10 is an inactivation modulatory protein of Kv4.3 and Kv1.4.","date":"2006","source":"American journal of physiology. Cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/16738002","citation_count":31,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12388308","id":"PMC_12388308","title":"Regulation of N- and C-type inactivation of Kv1.4 by pHo and K+: evidence for transmembrane communication.","date":"2002","source":"American journal of physiology. Heart and circulatory physiology","url":"https://pubmed.ncbi.nlm.nih.gov/12388308","citation_count":31,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"8663090","id":"PMC_8663090","title":"Characterization of the transcription unit of mouse Kv1.4, a voltage-gated potassium channel gene.","date":"1996","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/8663090","citation_count":30,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12901718","id":"PMC_12901718","title":"Trafficking of Kv1.4 potassium channels: interdependence of a pore region determinant and a cytoplasmic C-terminal VXXSL determinant in regulating cell-surface trafficking.","date":"2003","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/12901718","citation_count":30,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"14615029","id":"PMC_14615029","title":"Immunohistochemical localization of the voltage-gated potassium channel subunit Kv1.4 in the central nervous system of the adult rat.","date":"2003","source":"Journal of chemical neuroanatomy","url":"https://pubmed.ncbi.nlm.nih.gov/14615029","citation_count":29,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"27469045","id":"PMC_27469045","title":"Potential application of aerobic denitrifying bacterium Pseudomonas aeruginosa PCN-2 in nitrogen oxides (NOx) removal from flue gas.","date":"2016","source":"Journal of hazardous materials","url":"https://pubmed.ncbi.nlm.nih.gov/27469045","citation_count":29,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9875368","id":"PMC_9875368","title":"Functional expression of GFP-tagged Kv1.3 and Kv1.4 channels in HEK 293 cells.","date":"1998","source":"The European journal of neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/9875368","citation_count":29,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"19453640","id":"PMC_19453640","title":"Arachidonic acid potently inhibits both postsynaptic-type Kv4.2 and presynaptic-type Kv1.4 IA potassium channels.","date":"2009","source":"The European journal of neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/19453640","citation_count":28,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11024060","id":"PMC_11024060","title":"Mutations in the Kv beta 2 binding site for NADPH and their effects on Kv1.4.","date":"2001","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11024060","citation_count":28,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"16647042","id":"PMC_16647042","title":"Curcumin potently blocks Kv1.4 potassium channels.","date":"2006","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/16647042","citation_count":28,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"24463703","id":"PMC_24463703","title":"Reduced excitability of gp130-deficient nociceptors is associated with increased voltage-gated potassium currents and Kcna4 channel upregulation.","date":"2014","source":"Pflugers Archiv : European journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/24463703","citation_count":26,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"16426762","id":"PMC_16426762","title":"Pituitary adenylate cyclase activating polypeptide reduces expression of Kv1.4 and Kv4.2 subunits underlying A-type K(+) current in adult mouse olfactory neuroepithelia.","date":"2006","source":"Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/16426762","citation_count":26,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"36772986","id":"PMC_36772986","title":"Inhibiting mitochondrial inflammation through Drp1/HK1/NLRP3 pathway: A mechanism of alpinetin attenuated aging-associated cognitive impairment.","date":"2023","source":"Phytotherapy research : PTR","url":"https://pubmed.ncbi.nlm.nih.gov/36772986","citation_count":25,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"14608006","id":"PMC_14608006","title":"Inactivation and recovery in Kv1.4 K+ channels: lipophilic interactions at the intracellular mouth of the pore.","date":"2003","source":"The Journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/14608006","citation_count":25,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"16956965","id":"PMC_16956965","title":"Episodic ataxia type 1 mutation F184C alters Zn2+-induced modulation of the human K+ channel Kv1.4-Kv1.1/Kvbeta1.1.","date":"2006","source":"American journal of physiology. Cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/16956965","citation_count":25,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"29880505","id":"PMC_29880505","title":"Hexokinase 2 is targetable for HK1 negative, HK2 positive tumors from a wide variety of tissues of origin.","date":"2018","source":"Journal of nuclear medicine : official publication, Society of Nuclear Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/29880505","citation_count":24,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10573608","id":"PMC_10573608","title":"Co-localization of Shaker A-type K+ channel (Kv1.4) and AMPA-glutamate receptor (GluR4) immunoreactivities to dendrites of OFF-bipolar cells of goldfish retina.","date":"1999","source":"Journal of neurocytology","url":"https://pubmed.ncbi.nlm.nih.gov/10573608","citation_count":23,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"37001609","id":"PMC_37001609","title":"Hydroxysafflor yellow A protects against colitis in mice by suppressing pyroptosis via inhibiting HK1/NLRP3/GSDMD and modulating gut microbiota.","date":"2023","source":"Toxicology and applied pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/37001609","citation_count":22,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9359902","id":"PMC_9359902","title":"Modification of rat brain Kv1.4 channel gating by association with accessory Kvbeta1.1 and beta2.1 subunits.","date":"1997","source":"Pflugers Archiv : European journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/9359902","citation_count":22,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"14663209","id":"PMC_14663209","title":"Fluoxetine blocks cloned neuronal A-type K+ channels Kv1.4.","date":"2003","source":"Neuroreport","url":"https://pubmed.ncbi.nlm.nih.gov/14663209","citation_count":22,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9763623","id":"PMC_9763623","title":"Separable effects of human Kvbeta1.2 N- and C-termini on inactivation and expression of human Kv1.4.","date":"1998","source":"The Journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/9763623","citation_count":22,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10913143","id":"PMC_10913143","title":"A bovine adrenocortical Kv1.4 K(+) channel whose expression is potently inhibited by ACTH.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10913143","citation_count":21,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"14521958","id":"PMC_14521958","title":"Differential inhibition of transient outward currents of Kv1.4 and Kv4.3 by endothelin.","date":"2003","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/14521958","citation_count":21,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"26152125","id":"PMC_26152125","title":"IA Channels Encoded by Kv1.4 and Kv4.2 Regulate Circadian Period of PER2 Expression in the Suprachiasmatic Nucleus.","date":"2015","source":"Journal of biological rhythms","url":"https://pubmed.ncbi.nlm.nih.gov/26152125","citation_count":21,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"38367425","id":"PMC_38367425","title":"Oridonin inhibits bladder cancer survival and immune escape by covalently targeting HK1.","date":"2024","source":"Phytomedicine : international journal of phytotherapy and phytopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/38367425","citation_count":20,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"27582084","id":"PMC_27582084","title":"KCNA4 deficiency leads to a syndrome of abnormal striatum, congenital cataract and intellectual disability.","date":"2016","source":"Journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/27582084","citation_count":20,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"23996628","id":"PMC_23996628","title":"Founder mutations in NDRG1 and HK1 genes are common causes of inherited neuropathies among Roma/Gypsies in Slovakia.","date":"2013","source":"Journal of applied genetics","url":"https://pubmed.ncbi.nlm.nih.gov/23996628","citation_count":20,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"17959711","id":"PMC_17959711","title":"Ginsenoside Rg3 inhibits human Kv1.4 channel currents by interacting with the Lys531 residue.","date":"2007","source":"Molecular pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/17959711","citation_count":20,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"35364229","id":"PMC_35364229","title":"KLF2 mediates the suppressive effect of BDNF on diabetic intimal calcification by inhibiting HK1 induced endothelial-to-mesenchymal transition.","date":"2022","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/35364229","citation_count":19,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"24258481","id":"PMC_24258481","title":"Chromosome localization of the genes for ENO1, HK1, ADK, ACP2, MPI, ITPA, ACON1 and α-GAL in the American mink (Mustela vison).","date":"1983","source":"TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik","url":"https://pubmed.ncbi.nlm.nih.gov/24258481","citation_count":19,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"15454439","id":"PMC_15454439","title":"K+ activation of kir3.1/kir3.4 and kv1.4 K+ channels is regulated by extracellular charges.","date":"2004","source":"Biophysical journal","url":"https://pubmed.ncbi.nlm.nih.gov/15454439","citation_count":19,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"23330606","id":"PMC_23330606","title":"Characterization of histidine-aspartate kinase HK1 and identification of histidine phosphotransfer proteins as potential partners in a Populus multistep phosphorelay.","date":"2013","source":"Physiologia plantarum","url":"https://pubmed.ncbi.nlm.nih.gov/23330606","citation_count":17,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"23718837","id":"PMC_23718837","title":"Fine mapping and identification of blast resistance gene Pi-hk1 in a broad-spectrum resistant japonica rice landrace.","date":"2013","source":"Phytopathology","url":"https://pubmed.ncbi.nlm.nih.gov/23718837","citation_count":17,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"26321039","id":"PMC_26321039","title":"Structural characterization and modeling of the Borrelia burgdorferi hybrid histidine kinase Hk1 periplasmic sensor: A system for sensing small molecules associated with tick feeding.","date":"2015","source":"Journal of structural biology","url":"https://pubmed.ncbi.nlm.nih.gov/26321039","citation_count":17,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10394123","id":"PMC_10394123","title":"Anti-tumor effect of angiogenesis inhibitor TNP-470 on the human nasopharyngeal carcinoma cell line NPC/HK1.","date":"1999","source":"Oncology","url":"https://pubmed.ncbi.nlm.nih.gov/10394123","citation_count":17,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11122345","id":"PMC_11122345","title":"Subcellular compartmentalization of a potassium channel (Kv1.4): preferential distribution in dendrites and dendritic spines of neurons in the dorsal cochlear nucleus.","date":"2000","source":"The European journal of neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/11122345","citation_count":16,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"30871777","id":"PMC_30871777","title":"Fubp1 supports the lactate-Akt-mTOR axis through the upregulation of Hk1 and Hk2.","date":"2019","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/30871777","citation_count":15,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"31159234","id":"PMC_31159234","title":"New Naphtho-γ-Pyrones Isolated from Marine-Derived Fungus Penicillium sp. HK1-22 and Their Antimicrobial Activities.","date":"2019","source":"Marine drugs","url":"https://pubmed.ncbi.nlm.nih.gov/31159234","citation_count":15,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"17600124","id":"PMC_17600124","title":"Re-expression of a developmentally restricted potassium channel in autoimmune demyelination: Kv1.4 is implicated in oligodendroglial proliferation.","date":"2007","source":"The American journal of pathology","url":"https://pubmed.ncbi.nlm.nih.gov/17600124","citation_count":15,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"32270712","id":"PMC_32270712","title":"Cytotoxic Activity of Boesenbergia rotunda Extracts against Nasopharyngeal Carcinoma Cells (HK1). Cardamonin, a Boesenbergia rotunda Constituent, Inhibits Growth and Migration of HK1 Cells by Inducing Caspase-Dependent Apoptosis and G2/M-Phase Arrest.","date":"2020","source":"Nutrition and cancer","url":"https://pubmed.ncbi.nlm.nih.gov/32270712","citation_count":15,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"16000151","id":"PMC_16000151","title":"Neuronal transmission stimulates the phosphorylation of Kv1.4 channel at Ser229 through protein kinase A1.","date":"2005","source":"Journal of neurochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16000151","citation_count":15,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"27941652","id":"PMC_27941652","title":"Functional Divergence of Poplar Histidine-Aspartate Kinase HK1 Paralogs in Response to Osmotic Stress.","date":"2016","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/27941652","citation_count":14,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"35646662","id":"PMC_35646662","title":"Artesunate Inhibits the Development of Esophageal Cancer by Targeting HK1 to Reduce Glycolysis Levels in Areas With Zinc Deficiency.","date":"2022","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/35646662","citation_count":14,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"33671052","id":"PMC_33671052","title":"Isolation and Assessment of a Highly-Active Anti-Inflammatory Exopolysaccharide from Mycelial Fermentation of a Medicinal Fungus Cs-HK1.","date":"2021","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/33671052","citation_count":14,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"30036626","id":"PMC_30036626","title":"Protection of Bifidobacterial cells against antibiotics by a high molecular weight exopolysaccharide of a medicinal fungus Cs-HK1 through physical interactions.","date":"2018","source":"International journal of biological macromolecules","url":"https://pubmed.ncbi.nlm.nih.gov/30036626","citation_count":14,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"35314545","id":"PMC_35314545","title":"Nivolumab-induced Myositis and Myocarditis with Positive Anti-titin Antibody and Anti-voltage-gated Potassium Channel Kv1.4 Antibody.","date":"2022","source":"Internal medicine (Tokyo, Japan)","url":"https://pubmed.ncbi.nlm.nih.gov/35314545","citation_count":14,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"37079118","id":"PMC_37079118","title":"ErbB2-upregulated HK1 and HK2 promote breast cancer cell proliferation, migration and invasion.","date":"2023","source":"Medical oncology (Northwood, London, England)","url":"https://pubmed.ncbi.nlm.nih.gov/37079118","citation_count":13,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"21190652","id":"PMC_21190652","title":"A model of the interaction between N-type and C-type inactivation in Kv1.4 channels.","date":"2011","source":"Biophysical journal","url":"https://pubmed.ncbi.nlm.nih.gov/21190652","citation_count":13,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"31335655","id":"PMC_31335655","title":"Interleukin 6 decreases nociceptor expression of the potassium channel KV1.4 in a rat model of hand-arm vibration syndrome.","date":"2019","source":"Pain","url":"https://pubmed.ncbi.nlm.nih.gov/31335655","citation_count":13,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"16169070","id":"PMC_16169070","title":"A human protein-protein interaction network: a resource for annotating the proteome.","date":"2005","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/16169070","citation_count":1704,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"7477295","id":"PMC_7477295","title":"Clustering of Shaker-type K+ channels by interaction with a family of membrane-associated guanylate kinases.","date":"1995","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/7477295","citation_count":895,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"32296183","id":"PMC_32296183","title":"A reference map of the human binary protein interactome.","date":"2020","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/32296183","citation_count":849,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"16382104","id":"PMC_16382104","title":"International Union of Pharmacology. LIII. Nomenclature and molecular relationships of voltage-gated potassium channels.","date":"2005","source":"Pharmacological reviews","url":"https://pubmed.ncbi.nlm.nih.gov/16382104","citation_count":721,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"33961781","id":"PMC_33961781","title":"Dual proteome-scale networks reveal cell-specific remodeling of the human interactome.","date":"2021","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/33961781","citation_count":705,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"21873635","id":"PMC_21873635","title":"Phylogenetic-based propagation of functional annotations within the Gene Ontology consortium.","date":"2011","source":"Briefings in bioinformatics","url":"https://pubmed.ncbi.nlm.nih.gov/21873635","citation_count":656,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"8601796","id":"PMC_8601796","title":"Interaction between the C terminus of NMDA receptor subunits and multiple members of the PSD-95 family of membrane-associated guanylate kinases.","date":"1996","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/8601796","citation_count":627,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"9024696","id":"PMC_9024696","title":"GKAP, a novel synaptic protein that interacts with the guanylate kinase-like domain of the PSD-95/SAP90 family of channel clustering molecules.","date":"1997","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/9024696","citation_count":444,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"16344560","id":"PMC_16344560","title":"Diversification of transcriptional modulation: large-scale identification and characterization of putative alternative promoters of human genes.","date":"2005","source":"Genome research","url":"https://pubmed.ncbi.nlm.nih.gov/16344560","citation_count":409,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"9581762","id":"PMC_9581762","title":"CRIPT, a novel postsynaptic protein that binds to the third PDZ domain of PSD-95/SAP90.","date":"1998","source":"Neuron","url":"https://pubmed.ncbi.nlm.nih.gov/9581762","citation_count":264,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"2001794","id":"PMC_2001794","title":"Molecular cloning and characterization of two voltage-gated K+ channel cDNAs from human ventricle.","date":"1991","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/2001794","citation_count":221,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"9786987","id":"PMC_9786987","title":"Localization of postsynaptic density-93 to dendritic microtubules and interaction with microtubule-associated protein 1A.","date":"1998","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/9786987","citation_count":165,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"8495559","id":"PMC_8495559","title":"Heteromultimeric assembly of human potassium channels. Molecular basis of a transient outward current?","date":"1993","source":"Circulation research","url":"https://pubmed.ncbi.nlm.nih.gov/8495559","citation_count":156,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"10896669","id":"PMC_10896669","title":"Subunit composition determines Kv1 potassium channel surface expression.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10896669","citation_count":151,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"10428084","id":"PMC_10428084","title":"Subunit composition of Kv1 channels in human CNS.","date":"1999","source":"Journal of neurochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10428084","citation_count":135,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"8938729","id":"PMC_8938729","title":"Differential K+ channel clustering activity of PSD-95 and SAP97, two related membrane-associated putative guanylate kinases.","date":"1996","source":"Neuropharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/8938729","citation_count":129,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"11937501","id":"PMC_11937501","title":"Selectivity and promiscuity of the first and second PDZ domains of PSD-95 and synapse-associated protein 102.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11937501","citation_count":124,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"34857952","id":"PMC_34857952","title":"Paralog knockout profiling identifies DUSP4 and DUSP6 as a digenic dependence in MAPK pathway-driven cancers.","date":"2021","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/34857952","citation_count":116,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"24550280","id":"PMC_24550280","title":"Large-scale interaction profiling of PDZ domains through proteomic peptide-phage display using human and viral phage peptidomes.","date":"2014","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/24550280","citation_count":114,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"11352924","id":"PMC_11352924","title":"Interaction of gamma 1-syntrophin with diacylglycerol kinase-zeta. Regulation of nuclear localization by PDZ interactions.","date":"2001","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11352924","citation_count":103,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"1986382","id":"PMC_1986382","title":"Sequence and functional expression in Xenopus oocytes of a human insulinoma and islet potassium channel.","date":"1991","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/1986382","citation_count":87,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"11278603","id":"PMC_11278603","title":"The ERBB2/HER2 receptor differentially interacts with ERBIN and PICK1 PSD-95/DLG/ZO-1 domain proteins.","date":"2001","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11278603","citation_count":82,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"15123239","id":"PMC_15123239","title":"An improved method for the synthesis of cellulose membrane-bound peptides with free C termini is useful for PDZ domain binding studies.","date":"2004","source":"Chemistry & biology","url":"https://pubmed.ncbi.nlm.nih.gov/15123239","citation_count":75,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"10428758","id":"PMC_10428758","title":"Mutations in the KCNA1 gene associated with episodic ataxia type-1 syndrome impair heteromeric voltage-gated K(+) channel function.","date":"1999","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/10428758","citation_count":65,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"19912772","id":"PMC_19912772","title":"Human potassium channel genes: Molecular cloning and functional expression.","date":"1990","source":"Molecular and cellular neurosciences","url":"https://pubmed.ncbi.nlm.nih.gov/19912772","citation_count":55,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"16637659","id":"PMC_16637659","title":"Uncovering quantitative protein interaction networks for mouse PDZ domains using protein microarrays.","date":"2006","source":"Journal of the American Chemical Society","url":"https://pubmed.ncbi.nlm.nih.gov/16637659","citation_count":54,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"11149959","id":"PMC_11149959","title":"A mechanism for combinatorial regulation of electrical activity: Potassium channel subunits capable of functioning as Src homology 3-dependent adaptors.","date":"2001","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/11149959","citation_count":41,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"11744724","id":"PMC_11744724","title":"The PDZ1 domain of SAP90. Characterization of structure and binding.","date":"2001","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11744724","citation_count":40,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"11997254","id":"PMC_11997254","title":"Inward rectifier K+ channel Kir2.3 is localized at the postsynaptic membrane of excitatory synapses.","date":"2002","source":"American journal of physiology. Cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/11997254","citation_count":40,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"12860415","id":"PMC_12860415","title":"SAP97 increases Kv1.5 currents through an indirect N-terminal mechanism.","date":"2003","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/12860415","citation_count":39,"is_preprint":false,"source_track":"gene2pubmed"}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":54110,"output_tokens":9377,"usd":0.151493},"stage2":{"model":"claude-opus-4-6","input_tokens":13251,"output_tokens":4029,"usd":0.25047},"total_usd":0.88413,"stage1_batch_id":"msgbatch_01DzrsgVgYngY1hvM3DU1yF2","stage2_batch_id":"msgbatch_01KA9b7iRzKFdhoBUT7vCvSe","note":"batch pricing = 50% of standard","round2_stage1":{"model":"claude-sonnet-4-6","input_tokens":67140,"output_tokens":12827,"usd":0.196912},"round2_rules_fired":"R2","round2_stage2":{"model":"claude-opus-4-6","input_tokens":17154,"output_tokens":4176,"usd":0.285255}},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1997,\n      \"finding\": \"CaMKII phosphorylation of an N-terminal residue of Kv1.4 slows inactivation gating and accelerates recovery from N-type inactivated states, while dephosphorylation by calcineurin/inhibitor-1 phosphatase cascade induces a fast inactivating mode with increased cumulative inactivation during repetitive stimulation; the balance is regulated by intracellular Ca2+ concentration.\",\n      \"method\": \"In vitro kinase assay, phosphatase cascade manipulation, electrophysiology in heterologous expression\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct enzymatic phosphorylation assay with functional electrophysiological readout, multiple orthogonal methods\",\n      \"pmids\": [\"9133364\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"Kv1.4 undergoes both N-type (fast, NH2-terminal ball-and-chain) and C-type (slow, extracellular pore) inactivation; deletion of the NH2-terminal domain removes fast inactivation and reveals C-type inactivation; C-type inactivation governs the overall rate of recovery from inactivation; S4 voltage sensor mutation R454Q shifts inactivation voltage-dependence without altering inactivation rate.\",\n      \"method\": \"Two-electrode voltage clamp in Xenopus oocytes, N-terminal deletion mutagenesis, S4 point mutagenesis\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — reconstitution with mutagenesis in heterologous system, multiple orthogonal approaches\",\n      \"pmids\": [\"8788936\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"N-terminal palmitoylation of PSD-95 (at Cys3 and Cys5) is required for its membrane association and for its interaction with Kv1.4 in vivo; palmitoylation-deficient PSD-95 mutants fail to partition as integral membrane proteins and do not engage in PDZ-ion channel interactions.\",\n      \"method\": \"Metabolic labeling, mutagenesis, co-immunoprecipitation, membrane fractionation\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1/2 — metabolic labeling + mutagenesis + membrane fractionation + co-IP, multiple orthogonal methods\",\n      \"pmids\": [\"9459448\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"PSD-95-mediated clustering of Kv1.4 completely suppresses Kv1.4 internalization (t1/2 = 87 min alone); a palmitoylation/clustering-deficient PSD-95 mutant (C35S) instead enhances internalization rate (t1/2 = 16 min), demonstrating that clustering per se—not mere binding—stabilizes Kv1.4 at the cell surface.\",\n      \"method\": \"Cell-surface biotinylation assay, immunochemistry, electrophysiology in HEK293 cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — quantitative surface biotinylation with mutant controls and electrophysiology, strong mechanistic conclusion\",\n      \"pmids\": [\"10625685\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Kv1.4-containing channels are localized presynaptically on axons and near excitatory synaptic boutons in hippocampal mossy fiber and perforant path regions, positioned to regulate neurotransmitter release.\",\n      \"method\": \"Immunofluorescence confocal microscopy, electron microscopic immunocytochemistry\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — dual immunofluorescence and ultrastructural EM localization with functional context\",\n      \"pmids\": [\"9437018\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Antisense knockdown of Kv1.4 in rat hippocampus eliminates both early- and late-phase LTP and reduces paired-pulse facilitation in CA1 (a presynaptic effect), without affecting spatial memory or dentate gyrus LTP, demonstrating a presynaptic role for Kv1.4 in CA1 LTP.\",\n      \"method\": \"Intraventricular antisense oligonucleotide injection, RT-PCR, Western blot, in vivo electrophysiology, behavioral testing\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function with molecular verification and specific electrophysiological/behavioral phenotype\",\n      \"pmids\": [\"9844011\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Targeted deletion of Kv1.4 in mice does not eliminate the rapidly inactivating transient outward current (Ito) in adult ventricular myocytes, demonstrating that Kv1.4 is not the molecular basis of Ito in adult murine ventricle; the slow Ito component in left ventricular septal cells is eliminated in Kv1.4-/- mice.\",\n      \"method\": \"Gene targeting/knockout, patch-clamp electrophysiology, Western blot\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean knockout with electrophysiological and biochemical verification\",\n      \"pmids\": [\"9547391\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"In Kv4.2W362F × Kv1.4-/- double-mutant mice, both Ito,f and Ito,s are eliminated, revealing that upregulation of Kv1.4 encodes the slow Ito current observed in Kv4.2W362F-expressing ventricles; combined elimination causes severe QT prolongation, AV block, and ventricular tachycardia.\",\n      \"method\": \"Genetic epistasis (double-mutant mouse), patch-clamp, in vivo telemetric ECG, echocardiography\",\n      \"journal\": \"Circulation research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic epistasis with in vivo and ex vivo electrophysiological readouts\",\n      \"pmids\": [\"10884375\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Protonation of extracellular histidine H508 of Kv1.4 at acidic pH enhances C-type inactivation, slowing recovery from N-type inactivation and inhibiting current during repetitive pulsing; raising [K+]o or the K532Y mutation abolishes this pH-dependent slowing.\",\n      \"method\": \"Two-electrode voltage clamp in Xenopus oocytes, site-directed mutagenesis (H508Q, K532Y), N-terminal deletion\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — mutagenesis with voltage-clamp, multiple mutants tested\",\n      \"pmids\": [\"10896716\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"PSD-95 recruits Kv1.4 (but not Kv4.2) into lipid rafts through its palmitoylation; deletion of the PSD-95 binding motif on Kv1.4 or use of palmitoylation-deficient PSD-95 eliminates this raft recruitment.\",\n      \"method\": \"Detergent-resistant membrane fractionation, lipid raft patching/immunostaining, co-expression in heterologous cells, deletion mutagenesis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — biochemical fractionation + imaging + mutagenesis, multiple methods\",\n      \"pmids\": [\"14559911\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"N-glycosylation of Kv1.4 is required for its protein stability, proper cellular localization, and cell-surface trafficking; a pore region determinant of Kv1.4 and a sugar tree attached to the S1-S2 linker cooperate to promote cell-surface expression. Exchanging the pore trafficking determinant between Kv1.1 and Kv1.4 reverses glycosylation-dependent trafficking effects.\",\n      \"method\": \"N-glycosylation mutagenesis, chimeric channel construction, Western blot, immunofluorescence in transfected cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1/2 — mutagenesis + chimeras + quantitative trafficking assay\",\n      \"pmids\": [\"14688283\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"The N-terminus of Kv1.4 (residues approximately 73–148 in Kv1.5) binds directly to the spectrin repeats of alpha-actinin-2; this interaction is specific to Kv1.4 and Kv1.5 N-termini (not Kv1.1, 1.2, or 1.3) and is not modulated by calmodulin.\",\n      \"method\": \"Yeast two-hybrid analysis, in vitro binding assays, deletion analysis\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — yeast two-hybrid plus in vitro pull-down with deletion mapping\",\n      \"pmids\": [\"11389904\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"N-terminal cysteines Cys3 and Cys5 of PSD-95 are essential for PSD-95 multimerization and for forming cell-surface clusters with Kv1.4; however, cysteine mutants of PSD-95 retain membrane association and can still bind Kv1.4 as a binary complex, but cannot form a ternary complex with Kv1.4 and Fasciclin II.\",\n      \"method\": \"Mutagenesis, heterologous co-expression, cell surface imaging\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — mutagenesis with co-expression imaging and biochemical assays\",\n      \"pmids\": [\"9867876\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"PDZ2 of PSD-95 has the highest affinity for Kv1.4 and is the critical domain for efficient Kv1.4 clustering; the position of PDZ2 within full-length PSD-95 is prerequisite for efficient cluster formation (PDZ1-PDZ2 inversion abolishes clustering activity).\",\n      \"method\": \"Missense and deletion mutagenesis of PSD-95 PDZ domains, COS-1 cell co-expression, clustering assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — systematic mutagenesis with functional clustering readout\",\n      \"pmids\": [\"11723117\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"Kv beta3 (ferret ventricular beta-subunit) accelerates both fast and slow inactivation components of Kv1.4, increases the contribution of the slow inactivation component, slows recovery from inactivation (dependent on N-type inactivation), and slows deactivation, without altering voltage-dependent activation.\",\n      \"method\": \"Co-expression in Xenopus oocytes, two-electrode voltage clamp\",\n      \"journal\": \"The American journal of physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — co-expression with N-terminal deletion mutant to dissect mechanism\",\n      \"pmids\": [\"7631872\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"Kv beta2 enhances both amplitude and rate of inactivation of Kv1.4; NADPH-binding site mutations in Kv beta2 abolish its current-enhancing effect (reducing Kv1.4 protein levels) without disrupting physical association or its accelerating effect on inactivation, suggesting the putative oxidoreductase activity of Kv beta2 is involved in Kv1.4 processing/trafficking.\",\n      \"method\": \"Point mutagenesis of Kv beta2, yeast two-hybrid, Western blot, Xenopus oocyte co-expression\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — mutagenesis uncoupling two functions plus protein-level analysis\",\n      \"pmids\": [\"11024060\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Kvbeta1.2 modulates Kv1.4 through separable N- and C-terminal effects: the C-terminal of Kvbeta allosterically enhances N-type inactivation by the Kv1.4 alpha-ball and increases current expression; the Kvbeta1.2 N-terminal beta-ball directly blocks the channel pore. Yeast two-hybrid confirms alpha-beta interaction is restricted to alpha N-terminus and beta C-terminus.\",\n      \"method\": \"Two-microelectrode voltage clamp in Xenopus oocytes, N-terminal deletion mutants, yeast two-hybrid\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — deletion mutagenesis + yeast two-hybrid + electrophysiology\",\n      \"pmids\": [\"9763623\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"Co-expression of Kvbeta1.1 or Kvbeta2.1 with rat brain Kv1.4 in Xenopus oocytes accelerates activation time constant without affecting voltage dependence; Kvbeta2.1 (lacking N-terminal inactivation domain) is almost as effective as Kvbeta1.1 in speeding activation, and neither subunit substantially alters recovery from C-type inactivation.\",\n      \"method\": \"Two-electrode voltage clamp in Xenopus oocytes, co-expression\",\n      \"journal\": \"Pflugers Archiv : European journal of physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clean co-expression electrophysiology with domain-deleted beta subunit\",\n      \"pmids\": [\"9359902\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Riluzole irreversibly slows Kv1.4 inactivation by an oxidative mechanism involving a cysteine in the N-terminal inactivation domain; this effect is eliminated by reduced glutathione or DTT in the recording pipette, and does not occur when riluzole is applied at depolarized holding potential (where channel is inactivated and cysteine is protected).\",\n      \"method\": \"Whole-cell patch clamp on bovine adrenal zona fasciculata cells, antioxidant application, holding-potential protocol\",\n      \"journal\": \"The Journal of pharmacology and experimental therapeutics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — pharmacological + redox manipulation with mechanistic controls\",\n      \"pmids\": [\"11561084\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"Cysteine-oxidizing agents (DTBNP, chloramine-T) remove N-type inactivation of Kv1.4 and slow deactivation; these effects are reversed by DTT, demonstrating that the redox state of cysteine residues regulates both inactivation gating and channel closing.\",\n      \"method\": \"Whole-cell patch clamp in HEK-293 cells, cysteine-modifying reagents, DTT reversal\",\n      \"journal\": \"Pflugers Archiv : European journal of physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — pharmacological modification with reversal control\",\n      \"pmids\": [\"8584439\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"C-type inactivation of Kv1.4 is sensitive to both extracellular and intracellular K+; an intracellular S6 mutation (V561A) inverts the relationship between C-type inactivation and [K+]o; extracellular histidine H508 and lysine K532 mediate pH and K+ effects on both N- and C-type inactivation, indicating transmembrane communication through S6 and pore residues.\",\n      \"method\": \"Two-electrode voltage clamp in Xenopus oocytes, ion substitution, site-directed mutagenesis\",\n      \"journal\": \"American journal of physiology. Heart and circulatory physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — multiple mutants + ion substitution experiments dissecting coupled mechanisms\",\n      \"pmids\": [\"12388308\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"C-type inactivation and its coupling to N-type inactivation in Kv1.4 involves the cytoplasmic half of S6 as part of the N-terminal (ball) binding site; binding of the N-terminal domain or quinidine to S6 hydrophobic moieties orientates S6 into a C-type inactivated conformation via an allosteric mechanism.\",\n      \"method\": \"Voltage clamp of V561A mutant and N-terminal deleted Kv1.4 in Xenopus oocytes, quinidine blocking experiments\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1/2 — mutagenesis + pharmacology supporting allosteric coupling model\",\n      \"pmids\": [\"14608006\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"The cytoplasmic C-terminal VXXSL determinant and a pore-region determinant cooperate to regulate Kv1.4 cell-surface trafficking: removal of VXXSL inhibits surface levels only when the Kv1.4 pore (specifically a threonine in the deep pore) is present, showing interdependence between pore and C-terminal trafficking signals.\",\n      \"method\": \"Chimeric channel construction, cell-surface trafficking assays in transfected cells\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — systematic chimera and mutagenesis analysis of trafficking determinants\",\n      \"pmids\": [\"12901718\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"A truncated Kv1.1 polypeptide (Kv1.1N206Tag) forms heteromultimeric complexes with native Kv1.4 and Kv1.5, retains these complexes in the endoplasmic reticulum, and thereby suppresses surface expression — establishing a dominant-negative mechanism for long QT syndrome-like channel loss.\",\n      \"method\": \"Immunoprecipitation, double immunoprecipitation, subcellular fractionation, confocal immunofluorescence in GH3 cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — co-IP + subcellular fractionation + imaging, direct demonstration of ER trapping\",\n      \"pmids\": [\"9334228\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"DPP10 co-expression with Kv1.4 produces faster time to peak current, negative shifts in half-inactivation potential of steady-state activation and inactivation, and slows recovery from inactivation — effects similar to those on Kv4.3 — demonstrating DPP10 is a general modulator of voltage-gated K+ channel inactivation.\",\n      \"method\": \"Heterologous co-expression, whole-cell patch clamp, comparison with Kv4.3+DPP10\",\n      \"journal\": \"American journal of physiology. Cell physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — systematic co-expression electrophysiology with multiple channel combinations\",\n      \"pmids\": [\"16738002\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"EA1 mutations in KCNA1 (E325D, V404I, V408A, I177N) alter fast inactivation and repriming of heteromeric Kv1.4-Kv1.1 channels co-expressed with Kvbeta1.1 or Kvbeta1.2, decreasing the rate and degree of N-type inactivation and accelerating recovery from fast inactivation; Kvbeta1.x subunits modulate Kv1.4-Kv1.1 by increasing N-type inactivation and slowing repriming.\",\n      \"method\": \"Two-electrode voltage clamp of tandem-linked and co-expressed channel subunits in Xenopus oocytes, site-directed mutagenesis\",\n      \"journal\": \"The European journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — systematic mutagenesis and co-expression electrophysiology\",\n      \"pmids\": [\"17156368\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"EA1 mutation F184C in Kv1.1 markedly decreases Zn2+ equilibrium dissociation constants for both high- and low-affinity Zn2+ binding sites in heteromeric Kv1.4-Kv1.1/Kvbeta1.1 channels, sensitizing the channel to Zn2+ and further impairing N-type inactivation and repriming.\",\n      \"method\": \"Two-electrode voltage clamp in Xenopus oocytes, Zn2+ concentration-response analysis, mutagenesis\",\n      \"journal\": \"American journal of physiology. Cell physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — electrophysiology with ion and mutant analysis\",\n      \"pmids\": [\"16956965\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Neuronal transmission stimulates phosphorylation of Kv1.4 at Ser229 (within the T1 domain) via PKA, downstream of Ca2+ influx through NMDA receptors; mutation S229A enhances current density, demonstrating this phosphorylation reduces channel activity.\",\n      \"method\": \"In vitro protein kinase assay, phospho-specific Western blot, site-directed mutagenesis (S229A), patch clamp in cultured rat cortical neurons\",\n      \"journal\": \"Journal of neurochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro kinase assay + mutagenesis + electrophysiology in neurons\",\n      \"pmids\": [\"16000151\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Endothelin (via ETA receptor) inhibits Kv1.4 transient outward current (~85%) through PKC and CaMKII phosphorylation sites identified by mutagenesis in Xenopus oocytes; the degree of suppression differs from Kv4.3 due to different numbers/types of phosphorylation sites.\",\n      \"method\": \"Xenopus oocyte expression, endothelin receptor co-expression, mutagenesis of PKC and CaMKII phosphorylation sites\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — mutagenesis identifying specific phosphorylation sites with receptor-coupled signaling\",\n      \"pmids\": [\"14521958\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Extracellular lysine K532 of Kv1.4 acts as a 'guard' regulating K+ access to the selectivity filter; mutation K532Y abolishes both K+ activation and C-type inactivation; extracellular histidine H508 mediates inhibition at acidic pH by decreasing K+ access to the selectivity filter and favoring selectivity filter collapse.\",\n      \"method\": \"Two-electrode voltage clamp, site-directed mutagenesis (K532, H508), extracellular [K+] manipulation in Xenopus oocytes\",\n      \"journal\": \"Biophysical journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — mutagenesis with ion substitution experiments\",\n      \"pmids\": [\"15454439\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Ginsenoside Rg3 inhibits Kv1.4 currents by interacting with lysine K531 in the extracellular pore region; K531Y mutation abolishes Rg3 inhibition; raising [K+]o reduces Rg3 effect and Rg3 competes with TEA at the K531Y channel, confirmed by molecular docking showing K531 forms hydrogen bonds with Rg3.\",\n      \"method\": \"Two-electrode voltage clamp in Xenopus oocytes, point mutagenesis, competitive binding with TEA and K+, docking model\",\n      \"journal\": \"Molecular pharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — mutagenesis + competition experiments identifying specific binding residue\",\n      \"pmids\": [\"17959711\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"A missense variant (p.Arg89Gln) in KCNA4 (Kv1.4) causes a novel autosomal recessive syndrome of congenital cataract, abnormal striatum, intellectual disability, and ADHD; R89Q mutant channels expressed in Xenopus oocytes have significantly reduced current amplitude, and co-expression with WT shows dominant-negative-like reduction. KCNA4 is expressed in mouse brain, lens, and retina, and interacts with synaptotagmin I, DLG1, and DLG2.\",\n      \"method\": \"Whole-exome sequencing, two-electrode voltage clamp in Xenopus oocytes (WT, R89Q, WT/R89Q), RT-PCR, co-localization studies\",\n      \"journal\": \"Journal of medical genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — functional electrophysiology of disease mutant + protein interaction data + expression\",\n      \"pmids\": [\"27582084\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Loss of Kv1.4 (Kcna4-/- mice) shortens circadian period of SCN firing, locomotor activity, and PER2::LUC bioluminescence by ~0.5 h; combined loss of Kv1.4 and Kv4.2 advances daily activity onset by ~1.8 h, establishing that IA channels encoded by Kv1.4 regulate the molecular clock in SCN neurons.\",\n      \"method\": \"Genetic knockout (Kv1.4-/-, Kv4.2-/-, double KO), PER2::LUC bioluminescence recording from SCN explants, wheel-running activity monitoring\",\n      \"journal\": \"Journal of biological rhythms\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean genetic KO with molecular clock and behavioral readouts\",\n      \"pmids\": [\"26152125\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"In cortical pyramidal neurons, Kv1.4, Kv4.2, and Kv4.3 encode distinct components of IA; genetic disruption of Kv1.4 eliminates a minor but ubiquitous IA component; combined deletion of Kv4.2 and Kv4.3 unmasks the Kv1.4 component in all neurons; loss of individual Kv alpha-subunits produces subunit-specific electrical remodeling.\",\n      \"method\": \"Genetic knockouts (single and double), whole-cell patch clamp in cortical pyramidal neurons, pharmacological dissection\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic epistasis with electrophysiology, multiple knockout combinations\",\n      \"pmids\": [\"20371829\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Kv1.4 regional expression in rat ventricle correlates with the slowly recovering Ito component; Kv1.4 expressed in tsa-201 cells has identical recovery kinetics to the slow Ito component in myocytes, establishing Kv1.4 as the molecular basis of the slowly recovering Ito in rat heart.\",\n      \"method\": \"Regional mRNA/protein quantification, heterologous expression and patch clamp, comparison with native currents\",\n      \"journal\": \"The American journal of physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — expression correlation plus heterologous electrophysiology with kinetic matching\",\n      \"pmids\": [\"10330244\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Reduction of Kv1.4 alpha-subunit expression in bladder afferent neurons after spinal cord injury is associated with decreased A-type K+ current density and hyperexcitability (lower spike threshold, tonic firing) of capsaicin-sensitive C-fiber neurons.\",\n      \"method\": \"Whole-cell patch clamp, immunohistochemistry, RT-PCR in dissociated DRG neurons from SCI and intact rats\",\n      \"journal\": \"The Journal of urology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — correlative loss-of-expression with electrophysiological phenotype, no direct manipulation\",\n      \"pmids\": [\"23896350\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"IL-6 signaling via gp130 downregulates KV1.4 expression in nociceptors; vibration-induced muscle pain is accompanied by IL-6 elevation and KV1.4 reduction; antisense knockdown of KV1.4 in DRG mimics muscle hyperalgesia; knockdown of gp130 attenuates both hyperalgesia and KV1.4 reduction.\",\n      \"method\": \"Antisense knockdown of KV1.4 and gp130, neutralizing antibody against IL-6, mechanical hyperalgesia assay, protein/mRNA measurement\",\n      \"journal\": \"Pain\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — antisense knockdown with pathway-specific intervention (anti-IL-6, anti-gp130)\",\n      \"pmids\": [\"31335655\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Kv1.4 is re-expressed in oligodendrocyte precursor cells (AN2-positive) and premyelinating oligodendrocytes during EAE lesion formation, but not in mature oligodendrocytes; Kv1.4-expressing cells are actively proliferating and ensheath naked axons; ciliary neurotrophic factor knockout reduces Kv1.4+ oligodendroglial cells, suggesting Kv1.4 is implicated in oligodendroglial proliferation during remyelination.\",\n      \"method\": \"Confocal immunofluorescence, in vitro oligodendrocyte culture, EAE model, CNTF-KO mice\",\n      \"journal\": \"The American journal of pathology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — localization imaging + genetic model, no direct KV1.4 manipulation\",\n      \"pmids\": [\"17600124\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Arachidonic acid directly inhibits Kv1.4 current amplitude and shifts the voltage dependence of inactivation (-9 mV) at picomolar intracellular concentrations; the antioxidant Trolox shifts the voltage dependence of Kv1.4 activation (-32 mV extracellularly), suggesting redox-sensitive modulation of Kv1.4 gating.\",\n      \"method\": \"Whole-cell patch clamp in HEK293 cells transfected with Kv1.4, intracellular/extracellular drug application\",\n      \"journal\": \"The Journal of membrane biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct pharmacological application with voltage-clamp kinetic analysis\",\n      \"pmids\": [\"14724761\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"ACTH rapidly and potently reduces Kv1.4 mRNA in bovine adrenal zona fasciculata cells (t1/2 ~1 h, IC50 ~1.2 pM) via cAMP/PKA signaling (partially), leading to a parallel reduction in Kv1.4 A-type current over 72 h, demonstrating pretranslational control of Kv1.4 by the hypothalamic-pituitary-adrenal axis.\",\n      \"method\": \"Northern/quantitative PCR, whole-cell patch clamp, pharmacological manipulation of cAMP/PKA pathway\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — mRNA and current measurements with pathway inhibitor controls\",\n      \"pmids\": [\"10913143\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"Kv1.4 (KCNA4) is a voltage-gated, rapidly inactivating (A-type) K+ channel that undergoes both N-type (ball-and-chain) and C-type (pore-collapse) inactivation; CaMKII phosphorylation at the N-terminus and PKA phosphorylation at Ser229 regulate its inactivation kinetics and current density; its gating and surface stability are controlled by redox state of N-terminal cysteines, extracellular histidine H508 (pH sensor), and lysine K532 (K+ access guard); it is trafficked to the plasma membrane through interdependent pore-region and C-terminal VXXSL determinants and stabilized at the cell surface by PSD-95 clustering (which also recruits it to lipid rafts via PSD-95 palmitoylation); it forms heteromeric complexes with Kv1.1, Kv1.5, and Kvbeta subunits that modulate its gating and expression; it is localized presynaptically in hippocampal axons where it regulates LTP and neurotransmitter release, and in SCN neurons where it controls circadian period; loss-of-function mutations cause a syndrome of congenital cataract, striatal abnormalities, and intellectual disability, while IL-6/gp130 signaling downregulates its expression in nociceptors to promote pain hypersensitivity.\"\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\n```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1991,\n      \"finding\": \"KCNA4 (HK1/hPCN2) was molecularly cloned from human ventricle and functionally expressed in Xenopus oocytes, demonstrating it encodes a rapidly inactivating voltage-gated K+ channel with sensitivity to 4-aminopyridine.\",\n      \"method\": \"cDNA cloning, Xenopus oocyte expression, two-electrode voltage clamp\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — original functional reconstitution in heterologous system with electrophysiological characterization\",\n      \"pmids\": [\"2001794\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1991,\n      \"finding\": \"The hPCN1 isoform (related to KCNA4) expressed in Xenopus oocytes produces a slowly inactivating outward K+ current inhibited by 4-aminopyridine, establishing the electrophysiological signature of human Shaker-family channels including Kv1.4.\",\n      \"method\": \"cDNA isolation, Xenopus oocyte expression, two-electrode voltage clamp\",\n      \"journal\": \"Proceedings of the National Academy of Sciences\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — functional reconstitution with pharmacological characterization\",\n      \"pmids\": [\"1986382\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"Kv1.4 co-assembles with non-inactivating Kv1 subunits (Kv1.1, Kv1.2, Kv1.5) to form heteromultimeric channels; a single inactivating Kv1.4 subunit is sufficient to confer inactivation on the heteromeric complex, and hybrid channels display recovery kinetics closer to native cardiac transient outward current.\",\n      \"method\": \"Co-injection of cRNAs in Xenopus oocytes, two-electrode voltage clamp\",\n      \"journal\": \"Circulation research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct reconstitution of heteromultimers with functional characterization\",\n      \"pmids\": [\"8495559\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"The mouse Kcna4/Kv1.4 gene is contained in a single coding exon encoding a 654-amino-acid protein; the 5' NCR contains SP1 repeats and lacks TATA box; ATTTA repeats in the 3' NCR of the longer transcript reduce translational efficiency; the gene maps to mouse chromosome 2 and human chromosome 11p14.\",\n      \"method\": \"Genomic cloning, sequencing, Xenopus oocyte expression, in situ hybridization, fluorescence mapping\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct genomic characterization and functional expression\",\n      \"pmids\": [\"8020965\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"C-type inactivation governs recovery from inactivation in Kv1.4: removal of the N-terminal ball domain (fast inactivation) revealed a slow C-type inactivation process, and recovery rates from N-type and C-type inactivated states are nearly identical, indicating C-type inactivation is the rate-limiting step for recovery.\",\n      \"method\": \"N-terminal deletion mutagenesis, Xenopus oocyte two-electrode voltage clamp, site-directed mutagenesis of S4 voltage sensor (R454Q)\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — reconstitution with mutagenesis and biophysical analysis\",\n      \"pmids\": [\"8788936\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"Kv beta 3 co-expressed with Kv1.4 alpha-subunit accelerates both fast and slow components of inactivation, increases contribution of the slow inactivation component, slows recovery from inactivation (for intact Kv1.4 but not N-terminal deletion mutant), and slows deactivation, demonstrating that beta subunits modulate post-activation channel states.\",\n      \"method\": \"Xenopus oocyte co-expression, two-electrode voltage clamp\",\n      \"journal\": \"The American journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct reconstitution of alpha-beta subunit complex with functional analysis\",\n      \"pmids\": [\"7631872\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"PSD-95 family MAGUKs cluster Kv1.4 at the cell surface through direct binding of the channel's C-terminal cytoplasmic tail to PDZ domains of PSD-95, establishing the PDZ-mediated clustering mechanism for Shaker-type K+ channels.\",\n      \"method\": \"Yeast two-hybrid, co-immunoprecipitation, heterologous cell co-expression, immunofluorescence clustering assay\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal biochemical and cell biological evidence replicated across labs\",\n      \"pmids\": [\"7477295\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"The C-terminal -ETDV sequence of Kv1.4 is required for binding to and clustering with SAP97 and PSD-95; mutation of this motif abolishes both binding and clustering; PSD-95 induces cell-surface plaque-like clusters while SAP97 causes intracellular aggregates, demonstrating differential clustering activity of MAGUK family members.\",\n      \"method\": \"C-terminal deletion mutagenesis, heterologous cell co-expression, immunofluorescence\",\n      \"journal\": \"Neuropharmacology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — mutagenesis identifies specific binding motif, multiple orthogonal assays\",\n      \"pmids\": [\"8938729\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"Oxidizing cysteine-modifying reagents (DTBNP, chloramine-T) remove N-type inactivation of Kv1.4 and slow deactivation, effects reversed by DTT, indicating that redox state of cysteine residue(s) in the N-terminal inactivation domain regulates channel gating.\",\n      \"method\": \"Whole-cell patch clamp in HEK-293 cells expressing rat Kv1.4, cysteine-specific oxidizing/reducing agents\",\n      \"journal\": \"Pflugers Archiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct pharmacological manipulation with electrophysiological readout, single lab\",\n      \"pmids\": [\"8584439\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"The mouse Kv1.4 transcription unit produces two mRNAs (3.5 kb and 4.5 kb) from a common start site; ATTTA repeats in the 3' NCR of the longer transcript reduce translational efficiency ~4–5-fold compared with the shorter transcript; the basal promoter is GC-rich with SP1 repeats and lacks tissue specificity.\",\n      \"method\": \"5' RACE, reporter assays, Xenopus oocyte expression of individual transcripts\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct functional comparison of transcripts in expression system\",\n      \"pmids\": [\"8663090\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"CaMKII phosphorylation of an N-terminal residue of Kv1.4 slows inactivation gating and accelerates recovery from N-type inactivation; dephosphorylation by calcineurin accelerates inactivation 5–10-fold and promotes cumulative inactivation; the balance is regulated by intracellular Ca2+ concentration, making Kv1.4 inactivation Ca2+-sensitive.\",\n      \"method\": \"Xenopus oocyte expression, two-electrode voltage clamp, CaMKII and calcineurin application, frequency-dependent stimulation protocols\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — enzyme applied directly to channel, functional readout with mechanistic specificity\",\n      \"pmids\": [\"9133364\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"Kvbeta1.1 and Kvbeta2.1 subunits accelerate Kv1.4 activation kinetics without altering voltage dependence of activation or steady-state inactivation; Kvbeta2.1 modestly lengthens the slow time constant of recovery from inactivation.\",\n      \"method\": \"Xenopus oocyte co-expression, two-electrode voltage clamp\",\n      \"journal\": \"Pflugers Archiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 — direct reconstitution, single lab\",\n      \"pmids\": [\"9359902\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"A truncated Kv1.1 polypeptide (Kv1.1N206Tag) forms heteromultimeric complexes with native Kv1.4 and Kv1.5 in GH3 cells and is retained in the endoplasmic reticulum, providing a dominant-negative mechanism for long QT syndrome by trapping native channels in the ER.\",\n      \"method\": \"Double immunoprecipitation with channel-specific antibodies, subcellular fractionation, immunofluorescence/confocal colocalization, RNase protection assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal biochemical methods demonstrating complex formation and ER retention\",\n      \"pmids\": [\"9334228\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"N-type inactivation in Kv1.4 requires only a single inactivating subunit in heteromultimers; the proximal N-terminal region is critical; large deletions in the linker between the inactivation region and first transmembrane domain do not affect inactivation rate, suggesting the inactivation particle remains near the permeation pathway in the open state.\",\n      \"method\": \"Xenopus oocyte expression of Kv1.4-Kv1.5 tandems and co-expressed subunits, N-terminal deletion mutagenesis, two-electrode voltage clamp\",\n      \"journal\": \"The Journal of membrane biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — tandem fusion constructs and mutagenesis with functional characterization\",\n      \"pmids\": [\"8661510\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"PSD-95 is palmitoylated on N-terminal cysteines 3 and 5, which is required for its partitioning as an integral membrane protein and for PDZ-mediated interaction with Kv1.4 in vivo; palmitoylation-deficient PSD-95 mutants fail to interact with Kv1.4 in living cells.\",\n      \"method\": \"Metabolic labeling with [3H]palmitate, mutagenesis of Cys3/Cys5, cell fractionation, co-immunoprecipitation\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — biochemical identification of PTM with mutagenesis and functional consequence on channel interaction\",\n      \"pmids\": [\"9459448\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Kv1.4-containing channels are localized presynaptically on axons and near excitatory synaptic boutons in hippocampal perforant path and mossy fiber regions, as determined by immunofluorescence and ultrastructural immunogold electron microscopy.\",\n      \"method\": \"Confocal immunofluorescence, electron microscopic immunocytochemistry with anti-Kv1.4 antibody\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — ultrastructural localization with subcellular resolution\",\n      \"pmids\": [\"9437018\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Targeted deletion of Kv1.4 in mice does not eliminate the rapidly inactivating transient outward current (Ito) in adult ventricular myocytes; Kv4 subfamily channels are not upregulated in knockout mice, indicating Kv1.4 is not the primary molecular basis of Ito in adult murine ventricle.\",\n      \"method\": \"Targeted gene disruption (knockout mice), whole-cell patch clamp of isolated ventricular myocytes, Western blot\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean genetic knockout with electrophysiological readout in primary cells\",\n      \"pmids\": [\"9547391\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Kvbeta1.2 has three separable effects on Kv1.4: (1) a current-enhancing effect via the C-terminus, (2) allosteric enhancement of N-type inactivation by the alpha-ball, and (3) direct open-channel block by the beta-ball; the alpha-beta interaction is restricted to the N-terminus of Kv1.4 and C-terminus of Kvbeta1.2, with no direct interaction between the Kv1.4 alpha-ball and the Kvbeta subunit.\",\n      \"method\": \"Xenopus oocyte co-expression, two-electrode voltage clamp, N-terminal deletion mutants of Kv1.4, Kvbeta domain deletion mutants, yeast two-hybrid\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — mutagenesis of both subunits combined with functional reconstitution and protein interaction assays\",\n      \"pmids\": [\"9763623\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Antisense knockdown of Kv1.4 in rat hippocampus eliminates both early- and late-phase LTP and reduces paired-pulse facilitation in CA1 neurons without affecting spatial memory or dentate gyrus LTP, demonstrating a presynaptic role for Kv1.4 in CA1 LTP.\",\n      \"method\": \"Intraventricular antisense oligodeoxyribonucleotide injection, RT-PCR, Western blot, in vivo electrophysiology, Morris water maze behavioral testing\",\n      \"journal\": \"Proceedings of the National Academy of Sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo knockdown with multiple electrophysiological and behavioral readouts, single lab\",\n      \"pmids\": [\"9844011\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"N-terminal cysteines 3 and 5 of PSD-95 are essential for PSD-95 self-association (multimerization) and formation of cell-surface clusters with Kv1.4, but not for membrane association or binary binding to Kv1.4; multimerization is required for ternary complex formation with Kv1.4 and Fasciclin II.\",\n      \"method\": \"Mutagenesis of PSD-95 N-terminal cysteines, heterologous cell co-expression, immunofluorescence clustering assay, co-immunoprecipitation\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — mutagenesis with multiple functional assays distinguishing binary binding from multimerization-dependent clustering\",\n      \"pmids\": [\"9867876\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Regional differences in rat ventricular Ito are explained by differential expression of Kv1.4 (encoding slow-recovering Ito) and Kv4.2/Kv4.3 (encoding fast-recovering Ito); Kv1.4 protein and mRNA correlate with slow Ito density, and Kv1.4 kinetics in heterologous cells match slow Ito in myocytes.\",\n      \"method\": \"Western blot, Northern blot, patch clamp of ventricular myocytes and tsa-201 cells expressing individual channel subunits\",\n      \"journal\": \"The American journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — protein/mRNA correlation with direct functional comparison in heterologous system\",\n      \"pmids\": [\"10330244\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Kv1 channel subunit composition determines surface expression: homotetrameric Kv1.4 localizes to the cell surface, while Kv1.1 is retained in ER; heteromeric assembly with Kv1.4 increases surface expression of Kv1.1 and Kv1.2 in a dose-dependent manner; Kvbeta subunits promote surface expression of each Kv1 complex.\",\n      \"method\": \"Transfection of mammalian cells and hippocampal neurons, immunofluorescence, surface biotinylation, Western blot\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — systematic comparison of homo- and heteromers with direct surface expression measurement\",\n      \"pmids\": [\"10896669\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Acidosis inhibits Kv1.4 during repetitive pulsing by slowing recovery from N-type inactivation; protonation of extracellular histidine H508 enhances C-type inactivation, which in turn slows recovery from N-type inactivation; elevated [K+]o and the K532Y mutation also abolish the slowing effect, linking extracellular pore gating to N-type inactivation recovery.\",\n      \"method\": \"Xenopus oocyte two-electrode voltage clamp, site-directed mutagenesis (H508Q, K532Y), N-terminal deletion mutants, ion substitution experiments\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — mutagenesis identifies specific residue, multiple orthogonal perturbations\",\n      \"pmids\": [\"10896716\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"PSD-95 clustering completely suppresses Kv1.4 internalization (t1/2 = 87 min when alone); a non-clustering mutant C35S-PSD-95 enhances internalization rate (t1/2 = 16 min); clustering is necessary and sufficient for internalization suppression, revealing a new role for PSD-95 in stabilizing channels at the cell surface.\",\n      \"method\": \"Cell-surface biotinylation assay in transfected HEK293 cells, GFP-tagged Kv1.4 co-expression, electrophysiology\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — quantitative surface biotinylation with clustering mutants, functional electrophysiological controls\",\n      \"pmids\": [\"10625685\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Genetic elimination of both Ito,f (Kv4.2W362F dominant-negative) and Ito,s (Kv1.4 knockout) in mice causes marked QT prolongation, atrioventricular block, ventricular tachycardia, and early afterdepolarizations, demonstrating that upregulation of Kv1.4 underlies the slow Ito in Kv4.2W362F-expressing ventricles and that both currents together are required for normal cardiac electrical function.\",\n      \"method\": \"Transgenic/knockout mouse cross (Kv4.2W362F x Kv1.4-/-), in vivo telemetric ECG, patch clamp of isolated ventricular myocytes, histology, echocardiography\",\n      \"journal\": \"Circulation research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean double-genetic model with in vivo and ex vivo electrophysiological phenotyping\",\n      \"pmids\": [\"10884375\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"ACTH potently and rapidly reduces Kv1.4 mRNA expression in bovine adrenal zona fasciculata cells (t1/2 ~1 h, IC50 ~1.2 pM) via a cAMP/PKA-partially dependent mechanism, leading to decreased A-type current over 72 h, demonstrating pretranslational regulation of Kv1.4 by the hypothalamic-pituitary-adrenal axis.\",\n      \"method\": \"cDNA cloning from bovine adrenal cortex, quantitative mRNA analysis, whole-cell patch clamp, cAMP analog and PKA inhibitor experiments\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — mechanistic dissection of regulatory pathway with functional current measurements, single lab\",\n      \"pmids\": [\"10913143\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"The N-terminus of Kv1.4 (and Kv1.5) binds to the internal spectrin repeats of alpha-actinin-2; this interaction is specific (not observed for Kv1.1, 1.2, or 1.3); the Kv1.5 binding region maps to residues 73–148 of the N-terminus; calmodulin does not affect this interaction.\",\n      \"method\": \"Yeast two-hybrid analysis, in vitro GST pulldown binding assays, N-terminal deletion mapping\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — yeast two-hybrid plus in vitro pulldown, single lab, no in vivo validation\",\n      \"pmids\": [\"11389904\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"The PDZ2 domain of PSD-95 is required for efficient clustering of Kv1.4; the position of PDZ2 in full-length PSD-95 is also prerequisite for normal cluster formation; PDZ1 dysfunction does not impair clustering, revealing that high-affinity PDZ2-ligand binding and correct multi-domain architecture both determine clustering efficiency.\",\n      \"method\": \"Site-directed mutagenesis of individual PDZ domains in full-length PSD-95, PDZ inversion constructs, COS-1 cell co-expression, immunofluorescence clustering assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — systematic mutagenesis with domain inversion constructs, multiple cell biology assays\",\n      \"pmids\": [\"11723117\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Riluzole irreversibly slows Kv1.4 inactivation (tau_i from 29 to 623 ms) by an oxidative, voltage-dependent mechanism: the effect is blocked by reducing agents (glutathione, DTT) and absent when applied at depolarized holding potentials, implicating a cysteine in the N-terminal inactivation domain as the target; riluzole also reversibly inhibits Kv1.4 current (IC50 = 70 μM) by a separate mechanism.\",\n      \"method\": \"Whole-cell patch clamp in bovine adrenal zona fasciculata cells, antioxidant and non-hydrolyzable ATP controls, holding potential manipulation\",\n      \"journal\": \"The Journal of pharmacology and experimental therapeutics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — mechanistic dissection with pharmacological controls, single lab\",\n      \"pmids\": [\"11561084\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Kv beta 2 enhances Kv1.4 current amplitude and accelerates inactivation; mutations in Kv beta 2 that disrupt the NADPH binding or catalytic site abolish the expression-enhancing effect but not the acceleration of inactivation, suggesting that the oxidoreductase activity of Kv beta 2 is required for correct processing/surface expression of Kv1.4 but not for modulation of inactivation kinetics.\",\n      \"method\": \"Xenopus oocyte co-expression, two-electrode voltage clamp, site-directed mutagenesis of Kvbeta2 NADPH-binding and catalytic sites, Western blot of Kv1.4 protein levels, yeast two-hybrid\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — mutagenesis of putative enzymatic site with functional dissection of two separate effects, protein-level validation\",\n      \"pmids\": [\"11024060\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"C-type inactivation of Kv1.4 is sensitive to extracellular K+ (inhibited by elevated [K+]o), intracellular K+ (removal speeds C-type inactivation), and extracellular pH via histidine H508; a V561A mutation on the intracellular side of S6 inverts the C-type inactivation relationship with [K+]o; K532Y mutation slows C-type inactivation and abolishes pH dependence, demonstrating transmembrane communication between intracellular S6 and extracellular pore mouth in regulating inactivation.\",\n      \"method\": \"Xenopus oocyte two-electrode voltage clamp, N-terminal deletion mutant (fKv1.4ΔN), site-directed mutagenesis (V561A, K532Y, H508), ion substitution\",\n      \"journal\": \"American journal of physiology. Heart and circulatory physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — comprehensive mutagenesis with multiple ion-substitution experiments, mechanistic model validated\",\n      \"pmids\": [\"12388308\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"N-glycosylation of Kv1.4 (but not Kv1.1) promotes protein stability and cell-surface trafficking; preventing glycosylation decreases Kv1.4 protein stability, causes intracellular retention, and reduces surface expression; a pore region determinant determines whether glycosylation positively or negatively affects trafficking, and this determinant can be transferred to chimeric Kv1.1 proteins.\",\n      \"method\": \"Glycosylation inhibitors and site-directed mutagenesis of glycosylation sites in Kv1.1 and Kv1.4, chimeric channel constructs, surface biotinylation, immunofluorescence, Western blot\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — chimeric channel approach identifies transferable determinant, multiple orthogonal assays\",\n      \"pmids\": [\"14688283\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"PSD-95 palmitoylation is required to recruit Kv1.4 (but not Kv4.2) into lipid rafts; co-expression of PSD-95 increases raft-associated Kv1.4; deletion of the Kv1.4 C-terminal PSD-95 binding motif or substitution of palmitoylation-deficient PSD-95 eliminates raft recruitment, providing the first evidence that PSD-95 binding recruits Kv channels into lipid raft microdomains.\",\n      \"method\": \"Detergent-resistant membrane fractionation from rat brain, heterologous co-expression, lipid raft patching, immunostaining, deletion and palmitoylation mutants\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — native brain fractionation plus reconstitution with mutagenesis, multiple orthogonal approaches\",\n      \"pmids\": [\"14559911\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Kv1.4 cell-surface trafficking requires both a pore region determinant and a C-terminal VXXSL motif; removing VXXSL inhibits surface expression only when the Kv1.4 pore is present; the relevant subregion maps to a threonine residue in the deep pore; these two trafficking determinants act interdependently.\",\n      \"method\": \"Chimeric channel constructs between Kv1.4 and Kv1.1 pore regions, VXXSL deletion and truncation mutants, surface biotinylation, immunofluorescence in transfected cells\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — systematic chimeric and deletion analysis with quantitative surface expression assay\",\n      \"pmids\": [\"12901718\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"C-type inactivation in Kv1.4 involves allosteric coupling between the N-terminal inactivation ball or lipophilic compounds (like quinidine) and the cytoplasmic half of S6; binding of the N-terminal domain or quinidine to S6 shifts the channel into a conformation resembling the C-type inactivated state; the V561A mutation reduces affinity for both quinidine and the N-terminal domain, confirming S6 as part of the N-terminal binding site.\",\n      \"method\": \"Xenopus oocyte two-electrode voltage clamp, N-terminal deletion + V561A double mutant, quinidine pharmacology, varied [K+]o\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — mutagenesis with pharmacological probes identifies allosteric mechanism\",\n      \"pmids\": [\"14608006\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Arachidonic acid and other cis-unsaturated fatty acids inhibit Kv1.4 current and accelerate inactivation in native bovine adrenal zona fasciculata cells; lysophospholipids activate the co-expressed TREK-1 channel but do not affect Kv1.4; ETYA also inhibits Kv1.4, indicating direct lipid modulation independent of active AA metabolites.\",\n      \"method\": \"Whole-cell patch clamp in native bovine AZF cells, fatty acid/lysophospholipid application, ETYA control\",\n      \"journal\": \"The Journal of membrane biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct pharmacological modulation in native cells, single lab\",\n      \"pmids\": [\"14724761\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"An extracellular lysine residue K532 in Kv1.4 acts as a 'guard' regulating K+ access to the selectivity filter; mutation K532Y abolishes both K+ activation and C-type inactivation; protonation of H508 at acidic pH also abolishes K+ activation, indicating that extracellular charges regulate selectivity filter open probability.\",\n      \"method\": \"Xenopus oocyte two-electrode voltage clamp, site-directed mutagenesis (K532, H508), varied [K+]o and pH\",\n      \"journal\": \"Biophysical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — mutagenesis of specific residues with systematic ion and pH manipulation\",\n      \"pmids\": [\"15454439\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Neuronal transmission (via NMDA receptor Ca2+ influx) stimulates PKA phosphorylation of Kv1.4 at Ser229 in the T1 domain; glutamate, high K+, or K+ channel blockers increase Ser229 phosphorylation; TTX or Ca2+ depletion reduces it; Ser229Ala mutation enhances current density, indicating phosphorylation at this site reduces Kv1.4 channel activity.\",\n      \"method\": \"In vitro kinase assay, Western blot with phospho-Ser229-specific antibody in cultured rat cortical neurons, mutagenesis (Ser229Ala), pharmacological manipulation of neurotransmission\",\n      \"journal\": \"Journal of neurochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro kinase assay plus site-specific antibody plus mutagenesis with functional current measurement\",\n      \"pmids\": [\"16000151\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"EA1 mutations in KCNA1 (E325D, V404I, V408A, I177N) that line the pore or S1 segment of Kv1.1 alter fast inactivation of heteromeric Kv1.4-Kv1.1/Kvbeta1.1 and Kvbeta1.2 channels by decreasing rate and degree of N-type inactivation and accelerating recovery from inactivation; Kvbeta1.1/1.2 subunits regulate the proportion of wild-type Kv1.4-Kv1.1 channels available to open.\",\n      \"method\": \"Tandem-linked Kv1.4-Kv1.1 constructs expressed in Xenopus oocytes, two-electrode voltage clamp, EA1 point mutations\",\n      \"journal\": \"The European journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — tandem constructs eliminate subunit stoichiometry ambiguity; systematic mutagenesis of EA1 mutations\",\n      \"pmids\": [\"17156368\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"DPP10 modulates Kv1.4 inactivation similarly to its known effects on Kv4.3: co-expression causes faster time to peak current and negatively shifts half-inactivation potential; however, DPP10 slows rather than speeds recovery from inactivation in Kv1.4, demonstrating DPP10 as a general modulator of voltage-gated K+ channel inactivation acting on different inactivation states than KChIP2b.\",\n      \"method\": \"Xenopus oocyte co-expression, two-electrode voltage clamp, DPP10 transmembrane domain truncation mutants\",\n      \"journal\": \"American journal of physiology. Cell physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 — direct reconstitution in Xenopus oocytes with systematic comparison, single lab\",\n      \"pmids\": [\"16738002\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"EA1 mutation F184C in Kv1.1 sensitizes heteromeric Kv1.4-Kv1.1/Kvbeta1.1 channels to Zn2+: the complex has high-affinity (<10 μM) and low-affinity (<0.5 mM) Zn2+ binding sites; F184C decreases equilibrium dissociation constants for both sites, slows activation, increases time-to-peak, decreases N-type inactivation rate, and slows repriming compared with wild-type channels.\",\n      \"method\": \"Tandem Kv1.4-Kv1.1 constructs in Xenopus oocytes, two-electrode voltage clamp, Zn2+ dose-response, F184C mutation\",\n      \"journal\": \"American journal of physiology. Cell physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — tandem constructs with systematic Zn2+ concentration series and mutagenesis\",\n      \"pmids\": [\"16956965\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Ginsenoside Rg3 inhibits Kv1.4 channel current by interacting with residue Lys531; K531Y mutation abolishes the Rg3 effect; elevated [K+]o reduces Rg3 inhibition; Rg3 shifts K+ activation curve rightward and competes with TEA, with molecular docking showing hydrogen bonds between Rg3 and Lys531.\",\n      \"method\": \"Xenopus oocyte expression, two-electrode voltage clamp, site-directed mutagenesis (K531Y and others), K+ and TEA competition experiments, molecular docking\",\n      \"journal\": \"Molecular pharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — mutagenesis identifies binding residue with pharmacological competition assays, single lab\",\n      \"pmids\": [\"17959711\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Kv1.4 is re-expressed in oligodendrocyte precursor cells (AN2-positive) and premyelinating oligodendrocytes during experimental autoimmune encephalomyelitis but not in mature oligodendrocytes or healthy adult spinal cord; Kv1.4-positive cells are actively proliferating and ensheathing naked axons, suggesting a role in oligodendroglial cell cycle progression during remyelination.\",\n      \"method\": \"Confocal immunofluorescence with cell-type markers, in vitro oligodendrocyte precursor culture, proliferation assays, ciliary neurotrophic factor knockout mice\",\n      \"journal\": \"The American journal of pathology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — cell-type-specific localization with proliferation correlation and genetic model, single lab\",\n      \"pmids\": [\"17600124\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Arachidonic acid (1 pM intracellular) inhibits Kv1.4-mediated IA by >50% and shifts voltage dependence of inactivation by -9 mV; Trolox C (antioxidant) slows AA effects on amplitude and shifts Kv1.4 activation by -32 mV, implicating an oxidative mechanism; these effects are direct on the channel alpha-subunit.\",\n      \"method\": \"Whole-cell voltage clamp of HEK293 cells transfected with Kv1.4 or Kv4.2 rat cDNA, intracellular AA application, Trolox C antioxidant controls\",\n      \"journal\": \"The European journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct pharmacological modulation in heterologous system with antioxidant controls, single lab\",\n      \"pmids\": [\"19453640\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"In cortical pyramidal neurons, Kv1.4, Kv4.2, and Kv4.3 encode distinct components of macroscopic IA; in cells lacking both Kv4.2 and Kv4.3, Kv1.4 encodes a minor but ubiquitous IA component; loss of individual subunits causes Kv alpha-subunit-specific electrical remodeling.\",\n      \"method\": \"Single and double knockout mice (Kv1.4-/-, Kv4.2-/-, Kv4.3-/-), whole-cell patch clamp of cortical pyramidal neurons, 4-AP pharmacology\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean genetic dissection with double knockouts and pharmacological tools, replicated across genotypes\",\n      \"pmids\": [\"20371829\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Kv1.4 and Kv1.5 associate with native Kv1 heteromultimers in human CNS; sequential immunoprecipitation identifies a Kv1.3/1.4/1.1/1.2 tetramer in grey matter, Kv1.1/1.4 dimers in white matter and spinal cord, and apparent Kv1.4 homotetramers in all CNS regions, with Kvbeta1.1 coprecipitating with all alpha subunits in white matter.\",\n      \"method\": \"Sequential immunoprecipitation from human autopsy tissue (cerebral grey/white matter, spinal cord) with subunit-specific antibodies, immunoblotting\",\n      \"journal\": \"Journal of neurochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — sequential immunoprecipitation from native human tissue, comprehensive subunit mapping\",\n      \"pmids\": [\"10428084\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"A model of Kv1.4 inactivation demonstrates that N- and C-type inactivation are coupled through direct transitions between N- and C-type inactivated states; C-type inactivation begins at lower-voltage pre-activated states while N-type is coupled to the open state; C-type inactivation is the rate-limiting step for recovery, and a model with only distinct inactivated states without cross-transitions cannot reproduce experimental data.\",\n      \"method\": \"Two-electrode voltage clamp of Kv1.4 and Kv1.4ΔN in Xenopus oocytes, K532Y mutation, computational Markov chain modeling constrained by experimental data\",\n      \"journal\": \"Biophysical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — experimental data + validated computational model with mutagenesis constraints\",\n      \"pmids\": [\"21190652\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Spinal cord injury in rats reduces Kv1.4 protein and mRNA expression in bladder afferent neurons, accompanied by decreased A-type K+ current density and a hyperpolarizing shift in KA inactivation, resulting in increased nociceptor excitability with lower spike thresholds and tonic firing.\",\n      \"method\": \"Whole-cell patch clamp of dissociated L6-S1 DRG neurons, immunohistochemistry, real-time PCR, spinal transection model\",\n      \"journal\": \"The Journal of urology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — correlates Kv1.4 expression with electrophysiological excitability changes in spinal injury model, single lab\",\n      \"pmids\": [\"23896350\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Nociceptor-specific deletion of gp130 (IL-6 signal transducer) in SNS-gp130-/- mice increases A-type K+ currents and Kcna4 (Kv1.4) mRNA levels in sensory neurons, reducing excitability, suggesting IL-6/gp130 signaling normally suppresses Kv1.4 expression and thereby promotes nociceptor excitability.\",\n      \"method\": \"Conditional knockout mice, whole-cell patch clamp, TaqMan RT-PCR for Kcna4 and other ion channel mRNAs, action potential recording\",\n      \"journal\": \"Pflugers Archiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — conditional knockout with direct electrophysiological and mRNA measurement, single lab\",\n      \"pmids\": [\"24463703\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Loss of Kv1.4 (Kcna4-/-) shortens circadian period in SCN firing and locomotor activity by ~0.5 h and reduces PER2 expression period in SCN explants; combined loss of Kv1.4 and Kv4.2 advances daily activity onset by ~1.8 h in a light cycle, demonstrating that IA channels encoded by Kv1.4 feed back onto molecular clock (PER2) expression.\",\n      \"method\": \"Kv1.4-/- and Kv4.2-/- knockout mice crossed with Per2Luc reporter mice, SCN explant bioluminescence imaging, wheel-running locomotor activity recording\",\n      \"journal\": \"Journal of biological rhythms\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic knockout with PER2::LUC molecular clock readout, replicated in multiple genotypes\",\n      \"pmids\": [\"26152125\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"A missense variant p.Arg89Gln in KCNA4 causes a novel autosomal recessive syndrome with congenital cataract, striatal thinning, intellectual disability, and ADHD; the R89Q mutant produces significantly lower current amplitude than wild-type in Xenopus oocytes, and co-expression of wild-type and mutant results in intermediate current, indicating loss-of-function; KCNA4 mRNA is expressed in mouse brain, lens, and retina, and Kv1.4 co-localizes with cholinergic amacrine and rod bipolar cells.\",\n      \"method\": \"SNP arrays, autozygosity mapping, whole-exome sequencing, two-electrode voltage clamp in Xenopus oocytes, RT-PCR, immunohistochemistry\",\n      \"journal\": \"Journal of medical genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — functional expression of disease variant with electrophysiological characterization, confirmed in multiple family members\",\n      \"pmids\": [\"27582084\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"IL-6 downregulates Kv1.4 expression in dorsal root ganglion nociceptors via gp130/IL-6 receptor signaling, causing muscle hyperalgesia in a rat vibration model; antisense knockdown of Kv1.4 in DRG mimics vibration-induced muscle hyperalgesia; anti-IL-6 antibody attenuates both hyperalgesia and Kv1.4 downregulation.\",\n      \"method\": \"Rat hindlimb vibration model, local neutralizing anti-IL-6 injection, Kv1.4 antisense knockdown in DRG, gp130 knockdown, immunohistochemistry, behavioral pain testing\",\n      \"journal\": \"Pain\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — antisense knockdown phenocopies disease model; antibody rescue; receptor subunit knockdown epistasis, single lab\",\n      \"pmids\": [\"31335655\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"KCNA4 (Kv1.4) is a voltage-gated A-type K+ channel that undergoes rapid N-type inactivation (ball-and-chain mechanism from the N-terminus) coupled to slower C-type inactivation at the extracellular pore (involving residues H508 and K532), with C-type inactivation serving as the rate-limiting step for recovery; channel gating is regulated by CaMKII phosphorylation of N-terminal residues (slowing inactivation) and PKA phosphorylation at Ser229 (reducing current density), and by redox modification of N-terminal cysteines; Kv1.4 traffics to the cell surface via a pore-region determinant and C-terminal VXXSL motif, is clustered and stabilized at the surface by PSD-95 (via PDZ2-mediated binding to the C-terminal -ETDV motif) and recruited into lipid rafts through palmitoylated PSD-95; Kv beta subunits modulate inactivation kinetics and surface expression through interactions requiring NADPH-binding activity; Kv1.4 forms heteromultimers with other Kv1 subunits in native CNS tissue, encodes the slow-recovering Ito in cardiac and septal myocytes, is localized presynaptically in hippocampal axons where it regulates LTP, and its loss-of-function causes a human syndrome of striatal abnormality, congenital cataract, and intellectual disability.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"KCNA4 encodes Kv1.4, a voltage-gated potassium channel that conducts a rapidly inactivating A-type current and plays central roles in neuronal excitability, synaptic transmission, cardiac repolarization, and circadian rhythm regulation. Kv1.4 undergoes dual inactivation: fast N-type inactivation mediated by an N-terminal ball-and-chain domain and slow C-type inactivation involving pore collapse at the selectivity filter, with coupling between these processes governed by the cytoplasmic S6 segment, extracellular histidine H508, and lysine K532 [PMID:8788936, PMID:12388308, PMID:14608006]. Inactivation kinetics are dynamically regulated by CaMKII and PKA phosphorylation, redox modification of N-terminal cysteines, Kvβ auxiliary subunits, and PSD-95-mediated clustering that stabilizes channel surface expression via palmitoylation-dependent lipid raft recruitment [PMID:9133364, PMID:16000151, PMID:8584439, PMID:10625685, PMID:14559911]. Loss-of-function mutations in KCNA4 cause an autosomal recessive syndrome of congenital cataract, striatal abnormalities, and intellectual disability [PMID:27582084].\",\n  \"teleology\": [\n    {\n      \"year\": 1995,\n      \"claim\": \"Establishing Kv1.4's dual inactivation mechanism resolved how a single channel produces both fast and slow inactivation kinetics: N-terminal deletion unmasked a distinct C-type process that governs recovery from inactivation.\",\n      \"evidence\": \"N-terminal deletion mutagenesis and S4 mutation with two-electrode voltage clamp in Xenopus oocytes\",\n      \"pmids\": [\"8788936\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of C-type inactivation at atomic level not resolved\", \"Coupling mechanism between N- and C-type inactivation not yet mapped\"]\n    },\n    {\n      \"year\": 1996,\n      \"claim\": \"Demonstrating that oxidation of N-terminal cysteines removes N-type inactivation and slows deactivation established redox state as a physiological gating regulator of Kv1.4.\",\n      \"evidence\": \"Cysteine-modifying reagents with DTT reversal in patch-clamped HEK-293 cells expressing Kv1.4\",\n      \"pmids\": [\"8584439\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Specific cysteine residues responsible not individually identified\", \"In vivo relevance of redox modulation not demonstrated\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Identifying CaMKII phosphorylation of the N-terminus as a switch between fast- and slow-inactivating modes revealed how intracellular calcium dynamically tunes Kv1.4 channel behavior through a phosphorylation–dephosphorylation cycle.\",\n      \"evidence\": \"In vitro kinase assay, calcineurin/inhibitor-1 phosphatase manipulation, and electrophysiology in heterologous expression\",\n      \"pmids\": [\"9133364\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Exact phosphorylation site not pinpointed\", \"Physiological context in native neurons not tested\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Characterization of Kvβ subunit modulation showed that auxiliary β-subunits accelerate activation and differentially modulate N-type inactivation and recovery, with the Kvβ N-terminal ball providing an additional pore-blocking mechanism.\",\n      \"evidence\": \"Co-expression electrophysiology with N-terminal deletion mutants of Kvβ1 and Kvβ2 in Xenopus oocytes\",\n      \"pmids\": [\"7631872\", \"9359902\", \"9763623\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Stoichiometry of α/β complexes in native tissue uncertain\", \"NADPH-dependent oxidoreductase function of Kvβ2 in channel processing not fully mechanistically resolved\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Ultrastructural localization of Kv1.4 to presynaptic axons and boutons in hippocampal mossy fibers established the anatomical basis for its role in regulating neurotransmitter release.\",\n      \"evidence\": \"Immunofluorescence confocal and electron microscopic immunocytochemistry in rat hippocampus\",\n      \"pmids\": [\"9437018\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which specific release steps Kv1.4 controls not determined\", \"Relative contribution of Kv1.4 versus other presynaptic K+ channels not quantified\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Demonstrating that PSD-95 palmitoylation is required for its membrane association and interaction with Kv1.4 in vivo identified the lipid modification that anchors the scaffolding complex at the plasma membrane.\",\n      \"evidence\": \"Metabolic labeling, mutagenesis, co-immunoprecipitation, membrane fractionation\",\n      \"pmids\": [\"9459448\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether other scaffolding proteins contribute to Kv1.4 surface retention not addressed\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Kv1.4 knockout mice revealed that Kv1.4 is not the molecular basis of the predominant fast Ito in adult murine ventricle but encodes the slow Ito component in septal cells, clarifying the molecular identity of distinct cardiac transient outward currents.\",\n      \"evidence\": \"Gene targeting with patch-clamp electrophysiology and Western blot in Kv1.4−/− mouse ventricular myocytes\",\n      \"pmids\": [\"9547391\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Species differences in Kv1.4 contribution to cardiac Ito not fully mapped\", \"Compensatory remodeling in knockout not excluded\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Antisense knockdown of Kv1.4 in vivo eliminated both early- and late-phase LTP at CA1 via a presynaptic mechanism, directly linking presynaptic A-type current to hippocampal synaptic plasticity.\",\n      \"evidence\": \"Intraventricular antisense oligonucleotide injection with RT-PCR verification, in vivo electrophysiology and behavioral testing in rat\",\n      \"pmids\": [\"9844011\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether the effect is cell-autonomous to presynaptic terminals not proven\", \"Contribution of heteromeric Kv1.4/Kv1.1 complexes to LTP not dissected\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Quantitative surface biotinylation showed that PSD-95 clustering — not mere binary binding — suppresses Kv1.4 internalization, establishing that scaffold-mediated surface stabilization is the dominant mechanism controlling Kv1.4 membrane residence time.\",\n      \"evidence\": \"Cell-surface biotinylation assay with wild-type and palmitoylation-deficient PSD-95 in HEK293 cells\",\n      \"pmids\": [\"10625685\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Endocytic pathway mediating Kv1.4 internalization not identified\", \"In vivo significance of PSD-95-dependent stabilization not tested\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Identifying extracellular H508 as a pH sensor that enhances C-type inactivation and K532 as a K+ access guard established the molecular determinants linking extracellular environment to selectivity filter gating.\",\n      \"evidence\": \"Site-directed mutagenesis (H508Q, K532Y) with ion substitution and voltage clamp in Xenopus oocytes\",\n      \"pmids\": [\"10896716\", \"15454439\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of H508-to-selectivity filter communication unknown\", \"Physiological pH ranges where this operates in vivo not established\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Mapping the allosteric coupling between N-type and C-type inactivation to the cytoplasmic S6 helix (V561) resolved how N-terminal ball binding at S6 triggers conformational change at the distant selectivity filter.\",\n      \"evidence\": \"V561A mutagenesis with ion substitution and quinidine block experiments in Xenopus oocytes\",\n      \"pmids\": [\"12388308\", \"14608006\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural data confirming S6 conformational rearrangement\", \"Generalizability of V561 mechanism to other Kv1 family members not tested\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Discovery that PSD-95 palmitoylation recruits Kv1.4 specifically into lipid rafts (but not Kv4.2) revealed a mechanism for subtype-selective channel compartmentalization at the membrane.\",\n      \"evidence\": \"Detergent-resistant membrane fractionation and lipid raft patching with deletion mutagenesis\",\n      \"pmids\": [\"14559911\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of raft versus non-raft Kv1.4 localization on channel gating not tested\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Identification of interdependent pore-region and C-terminal VXXSL trafficking determinants, cooperating with N-glycosylation at the S1-S2 linker, defined the multi-signal code governing Kv1.4 forward trafficking to the cell surface.\",\n      \"evidence\": \"Chimeric channel construction, glycosylation mutagenesis, and cell-surface trafficking assays\",\n      \"pmids\": [\"12901718\", \"14688283\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"ER-to-Golgi versus Golgi-to-surface steps not distinguished\", \"Trafficking chaperones involved not identified\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Identifying PKA phosphorylation at Ser229 as an activity-dependent negative regulator of Kv1.4 current downstream of NMDA receptor–Ca2+ signaling established a feedback loop linking excitatory transmission to A-type current suppression in cortical neurons.\",\n      \"evidence\": \"In vitro kinase assay, phospho-specific Western blot, S229A mutagenesis, patch clamp in cultured rat cortical neurons\",\n      \"pmids\": [\"16000151\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which S229 phosphorylation reduces current (gating vs. trafficking) not resolved\", \"Whether this pathway operates in other neuron types unknown\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Kv1.4 knockout shortened the circadian period of SCN neuronal firing and locomotor behavior by ~0.5 h, and combined Kv1.4/Kv4.2 loss advanced activity onset by ~1.8 h, establishing A-type channels as regulators of the molecular clock.\",\n      \"evidence\": \"Kv1.4−/−, Kv4.2−/−, and double-KO mice with PER2::LUC bioluminescence from SCN explants and wheel-running assays\",\n      \"pmids\": [\"26152125\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism linking A-type current to transcription-translation feedback loop of the clock not identified\", \"Cell-type specificity within SCN not resolved\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Identification of the R89Q missense mutation as causative for a recessive syndrome of congenital cataract, striatal abnormalities, and intellectual disability linked human disease directly to Kv1.4 loss of function and dominant-negative channel suppression.\",\n      \"evidence\": \"Whole-exome sequencing in affected family, two-electrode voltage clamp of WT, R89Q, and WT/R89Q channels in Xenopus oocytes\",\n      \"pmids\": [\"27582084\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Pathogenic mechanism in lens and striatum not elucidated\", \"Only one family reported; genetic heterogeneity not explored\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Demonstrating that IL-6/gp130 signaling downregulates Kv1.4 in nociceptors and that Kv1.4 knockdown mimics pain hypersensitivity identified Kv1.4 as a molecular effector linking inflammatory cytokines to peripheral sensitization.\",\n      \"evidence\": \"Antisense knockdown of Kv1.4 and gp130, anti-IL-6 neutralizing antibody, mechanical hyperalgesia assay in vibration-induced muscle pain model\",\n      \"pmids\": [\"31335655\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether Kv1.4 downregulation is transcriptional or post-translational not determined\", \"Contribution of other A-type channels in nociceptors not excluded\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the structural basis of N-type/C-type inactivation coupling, the specific trafficking chaperones that recognize interdependent pore and C-terminal signals, and the mechanism by which Kv1.4-mediated A-type current feeds back onto the circadian transcription-translation loop.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No high-resolution structure of Kv1.4 in inactivated conformations\", \"Trafficking pathway intermediates and chaperones uncharacterized\", \"Molecular link between A-type current and clock gene regulation unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005215\", \"supporting_discovery_ids\": [1, 6, 7, 33]},\n      {\"term_id\": \"GO:0140299\", \"supporting_discovery_ids\": [8, 20, 29]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [3, 4, 9, 10, 22]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1, 21]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0005215\", \"supporting_discovery_ids\": []},\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [4, 5, 27, 33]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 27, 28, 36]},\n      {\"term_id\": \"R-HSA-382551\", \"supporting_discovery_ids\": [1, 6, 7, 34]},\n      {\"term_id\": \"R-HSA-9909396\", \"supporting_discovery_ids\": [32]}\n    ],\n    \"complexes\": [\n      \"Kv1.4/Kvβ heteromeric channel complex\",\n      \"Kv1.4/PSD-95 scaffold complex\",\n      \"Kv1.4/Kv1.1 heteromeric channel\"\n    ],\n    \"partners\": [\n      \"DLG4\",\n      \"KCNAB1\",\n      \"KCNAB2\",\n      \"KCNA1\",\n      \"KCNA5\",\n      \"ACTN2\",\n      \"DPP10\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\n```json\n{\n  \"mechanistic_narrative\": \"KCNA4 (Kv1.4) is a voltage-gated potassium channel that conducts a rapidly inactivating A-type K+ current, playing key roles in cardiac repolarization (slow-recovering Ito,s), presynaptic regulation of hippocampal LTP, nociceptor excitability, and circadian clock period modulation [PMID:2001794, PMID:10330244, PMID:9844011, PMID:26152125]. The channel undergoes fast N-type inactivation via a ball-and-chain mechanism at the N-terminus coupled to slower C-type inactivation at the extracellular pore (involving H508 and K532), with C-type inactivation serving as the rate-limiting step for recovery; these two inactivation processes are allosterically linked through the cytoplasmic S6 segment [PMID:8788936, PMID:12388308, PMID:14608006]. Channel gating is dynamically regulated by CaMKII/calcineurin phosphorylation of N-terminal residues, PKA phosphorylation at Ser229, and redox modification of N-terminal cysteines, while surface expression and clustering depend on PSD-95 PDZ2-mediated binding to the C-terminal ETDV motif, palmitoylation-dependent lipid raft recruitment, Kvβ subunit-assisted trafficking, and a pore-region/VXXSL dual determinant [PMID:9133364, PMID:16000151, PMID:8584439, PMID:7477295, PMID:14559911, PMID:11024060, PMID:12901718]. Loss-of-function mutation p.Arg89Gln causes an autosomal recessive syndrome of congenital cataract, striatal abnormality, and intellectual disability [PMID:27582084].\",\n  \"teleology\": [\n    {\n      \"year\": 1991,\n      \"claim\": \"Molecular cloning and functional expression established that KCNA4 encodes a rapidly inactivating, 4-AP-sensitive voltage-gated K+ channel, defining its biophysical identity within the Shaker family.\",\n      \"evidence\": \"cDNA cloning from human ventricle, Xenopus oocyte two-electrode voltage clamp\",\n      \"pmids\": [\"2001794\", \"1986382\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No structural model of the full-length channel\", \"Subunit stoichiometry of native channels unknown\"]\n    },\n    {\n      \"year\": 1993,\n      \"claim\": \"Demonstration that a single Kv1.4 subunit confers rapid inactivation on heteromeric Kv1.1/1.2/1.5 complexes explained how native A-type currents with intermediate kinetics arise from mixed-subunit assemblies.\",\n      \"evidence\": \"Co-injection of cRNAs in Xenopus oocytes with functional voltage clamp characterization\",\n      \"pmids\": [\"8495559\", \"8661510\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Native subunit stoichiometry not determined at single-channel level\", \"Heteromer assembly rules beyond pairwise not established\"]\n    },\n    {\n      \"year\": 1995,\n      \"claim\": \"Dissection of inactivation gating revealed that N-type (ball-and-chain) and C-type (pore) inactivation are coupled, with C-type inactivation as the rate-limiting step for recovery, resolving a longstanding question about why Kv1.4 recovery is much slower than N-type inactivation alone predicts.\",\n      \"evidence\": \"N-terminal deletion mutagenesis and voltage-sensor mutations in Xenopus oocytes\",\n      \"pmids\": [\"8788936\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of C-type inactivation at the pore not visualized\", \"Coupling mechanism between N-type ball and C-type gate at atomic resolution unknown\"]\n    },\n    {\n      \"year\": 1995,\n      \"claim\": \"PSD-95 was identified as the scaffolding partner that clusters Kv1.4 at the cell surface via PDZ-domain binding to the channel's C-terminal ETDV motif, establishing a paradigm for synaptic K+ channel localization.\",\n      \"evidence\": \"Yeast two-hybrid, co-immunoprecipitation, heterologous cell co-expression, and immunofluorescence clustering\",\n      \"pmids\": [\"7477295\", \"8938729\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo disruption of PSD-95–Kv1.4 interaction not performed genetically\", \"Whether PSD-95 clustering alters channel biophysics in neurons unresolved\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"CaMKII phosphorylation of N-terminal residues was shown to slow inactivation and accelerate recovery, while calcineurin-mediated dephosphorylation restores fast inactivation, establishing Ca²⁺-dependent bidirectional regulation of Kv1.4 gating.\",\n      \"evidence\": \"Direct enzyme application to Kv1.4-expressing Xenopus oocytes with voltage clamp\",\n      \"pmids\": [\"9133364\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Exact phosphorylation site(s) not identified by mass spectrometry\", \"In vivo physiological context of CaMKII regulation not tested\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Ultrastructural localization placed Kv1.4 at presynaptic axons and boutons in hippocampus, and antisense knockdown eliminated both early- and late-phase LTP at CA1, establishing a presynaptic role in synaptic plasticity.\",\n      \"evidence\": \"Immunogold electron microscopy and in vivo antisense knockdown with electrophysiology\",\n      \"pmids\": [\"9437018\", \"9844011\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Antisense approach lacks genetic specificity; conditional knockout confirmation absent\", \"Mechanism by which presynaptic Kv1.4 regulates LTP induction not defined\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Palmitoylation of PSD-95 N-terminal cysteines was found to be required for in vivo interaction with Kv1.4 and subsequent lipid raft recruitment, linking post-translational modification of the scaffold to channel microdomain targeting.\",\n      \"evidence\": \"Metabolic [³H]palmitate labeling, Cys3/5 mutagenesis, co-immunoprecipitation, later confirmed by raft fractionation from rat brain\",\n      \"pmids\": [\"9459448\", \"14559911\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether raft localization affects Kv1.4 single-channel conductance or open probability not tested\", \"Enzyme(s) catalyzing PSD-95 palmitoylation not identified in these studies\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Identification of H508 and K532 as extracellular pore residues governing pH-sensitive C-type inactivation, and V561 as the intracellular S6 residue allosterically coupled to the outer pore, defined the transmembrane communication pathway regulating recovery kinetics.\",\n      \"evidence\": \"Site-directed mutagenesis with ion-substitution and pH experiments in Xenopus oocytes\",\n      \"pmids\": [\"10896716\", \"12388308\", \"14608006\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No crystal or cryo-EM structure of Kv1.4 to validate structural interpretation\", \"Role of these residues in native cardiac or neuronal context not confirmed\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Combined genetic elimination of Kv4.2-mediated Ito,f and Kv1.4-mediated Ito,s in mice caused severe arrhythmias (QT prolongation, VT), proving that Kv1.4 encodes the slow-recovering transient outward current and that both Ito components are essential for cardiac repolarization.\",\n      \"evidence\": \"Kv4.2W362F transgenic × Kv1.4−/− knockout mice with telemetric ECG and patch clamp\",\n      \"pmids\": [\"10884375\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Human cardiac relevance not directly tested; species differences in Ito composition exist\", \"Compensatory remodeling in double-mutant mice not fully characterized\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Kvβ2 was shown to enhance Kv1.4 surface expression through an NADPH-binding-dependent mechanism distinct from its kinetic modulation of inactivation, separating the β-subunit's oxidoreductase-like chaperone function from its direct gating effects.\",\n      \"evidence\": \"Mutagenesis of Kvβ2 NADPH-binding and catalytic sites with co-expression in oocytes and Western blot of protein levels\",\n      \"pmids\": [\"11024060\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Kvβ2 acts as a true oxidoreductase on Kv1.4 or functions as a chaperone through NADPH-induced conformation unknown\", \"No in vivo trafficking assay\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Identification of a pore-region determinant and a C-terminal VXXSL motif as interdependent trafficking signals resolved how Kv1.4 achieves efficient cell-surface expression while the highly homologous Kv1.1 is retained in the ER.\",\n      \"evidence\": \"Chimeric Kv1.4/Kv1.1 channels, VXXSL deletion, surface biotinylation\",\n      \"pmids\": [\"14688283\", \"12901718\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Coat protein or adaptor recognizing VXXSL not identified\", \"Contribution of glycosylation versus VXXSL in native neurons not dissected\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"PKA phosphorylation at Ser229 in the T1 domain was identified as a neuronal-activity-dependent mechanism reducing Kv1.4 current density, adding a second kinase-based regulatory axis complementary to CaMKII-mediated gating modulation.\",\n      \"evidence\": \"Phospho-Ser229-specific antibody in cultured cortical neurons, in vitro kinase assay, S229A mutagenesis with electrophysiology\",\n      \"pmids\": [\"16000151\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Ser229 phosphorylation affects surface expression, open probability, or both not distinguished\", \"Downstream physiological consequence (e.g. firing rate change) not measured\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Sequential immunoprecipitation from human CNS tissue mapped native Kv1.4-containing heteromeric complexes — including Kv1.3/1.4/1.1/1.2 tetramers in grey matter and Kv1.1/1.4 dimers in white matter — providing the first systematic view of Kv1.4 heteromeric composition in the human brain.\",\n      \"evidence\": \"Sequential immunoprecipitation from human autopsy tissue with subunit-specific antibodies\",\n      \"pmids\": [\"10428084\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry within individual tetramers not determined\", \"Functional properties of specific native heteromers not reconstituted\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Kv1.4 knockout shortened circadian period by ~0.5 h and reduced PER2 expression period in SCN, revealing an unexpected feedback from membrane excitability (IA) onto the molecular clock.\",\n      \"evidence\": \"Kcna4−/− mice crossed with PER2::LUC reporter, SCN explant bioluminescence, wheel-running activity\",\n      \"pmids\": [\"26152125\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Signal transduction pathway from Kv1.4 current to PER2 transcription not identified\", \"Whether this is a direct cell-autonomous effect or network-level phenomenon not resolved\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"The p.Arg89Gln loss-of-function variant was identified as the cause of an autosomal recessive syndrome of congenital cataract, striatal thinning, and intellectual disability, establishing the first human Mendelian disease linked to KCNA4.\",\n      \"evidence\": \"Autozygosity mapping, whole-exome sequencing, functional expression of R89Q in Xenopus oocytes showing reduced current\",\n      \"pmids\": [\"27582084\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Only one family reported; independent replication in additional families not yet published\", \"Mechanism linking Kv1.4 loss-of-function to cataract formation not elucidated\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"IL-6/gp130 signaling was shown to downregulate Kv1.4 in nociceptors, and Kv1.4 antisense knockdown phenocopied vibration-induced hyperalgesia, mechanistically linking cytokine-driven Kv1.4 suppression to pain sensitization.\",\n      \"evidence\": \"Rat vibration model with anti-IL-6 antibody rescue, Kv1.4 antisense knockdown in DRG, gp130 conditional knockdown\",\n      \"pmids\": [\"31335655\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Kv1.4 downregulation is transcriptional or post-transcriptional not determined\", \"Relevance to chronic pain syndromes in humans not established\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"No high-resolution structure of Kv1.4 exists, the precise mechanism linking N-terminal ball binding at S6 to outer-pore C-type inactivation conformational change remains structurally unresolved, and the signaling pathway by which Kv1.4 current feeds back onto PER2 transcription in the SCN is unknown.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No cryo-EM or crystal structure of Kv1.4 homomeric or heteromeric channel\", \"Structural basis of N-type/C-type inactivation coupling not visualized\", \"Molecular link between Kv1.4-mediated IA and circadian clock gene expression unidentified\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005215\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [10, 37]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [6, 7, 21, 23, 31, 33]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [12, 21]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [15]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [0, 2, 15, 18, 44, 45]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [10, 37, 48, 51]},\n      {\"term_id\": \"R-HSA-382551\", \"supporting_discovery_ids\": [0, 1, 2, 20, 24]},\n      {\"term_id\": \"R-HSA-9909396\", \"supporting_discovery_ids\": [49]}\n    ],\n    \"complexes\": [\n      \"Kv1 heteromultimeric channel complex\",\n      \"Kv1.4/Kvβ complex\"\n    ],\n    \"partners\": [\n      \"DLG4\",\n      \"DLG1\",\n      \"KCNAB1\",\n      \"KCNAB2\",\n      \"KCNAB3\",\n      \"KCNA1\",\n      \"KCNA2\",\n      \"ACTN2\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}