{"gene":"KCNIP1","run_date":"2026-04-28T18:30:27","timeline":{"discoveries":[{"year":2002,"finding":"KChIP1 remodels inactivation gating of Kv4.1 and Kv4.3 channels by slowing the early phase of macroscopic inactivation, accelerating the late phase and closed-state inactivation, accelerating recovery from inactivation (3–5 fold), and promoting channel closing, without changing unitary conductance; an allosteric kinetic model shows KChIP1 mainly impairs open-state inactivation and lowers the energy barrier of closed-state inactivation.","method":"Whole-oocyte voltage-clamp and patch-clamp in Xenopus laevis oocytes; single-channel recordings; allosteric kinetic modeling","journal":"The Journal of physiology","confidence":"High","confidence_rationale":"Tier 1 — rigorous in vitro electrophysiology with single-channel recordings and quantitative kinetic modeling; replicated across two Kv4 subtypes","pmids":["11826158"],"is_preprint":false},{"year":2001,"finding":"KChIP1 differentially modulates Kv4.1 and Kv4.2: it slows Kv4.2 inactivation but accelerates Kv4.1 inactivation, shifts activation voltage in opposite directions for the two channels, yet increases current amplitude and accelerates recovery from inactivation for both; Kv4 N-terminus chimeras demonstrate that differential effects are mediated by the Kv4 N-terminal domain.","method":"Heterologous expression in Xenopus oocytes; whole-cell electrophysiology; Kv4.1/Kv4.2 N-terminus chimeras","journal":"FEBS letters","confidence":"High","confidence_rationale":"Tier 1 — in vitro electrophysiology with chimera-based domain mapping","pmids":["11423117"],"is_preprint":false},{"year":2004,"finding":"Crystal structure (2.0 Å) of KChIP1 core domain in complex with the N-terminal fragment of Kv4.2 (Kv4.2N30) reveals a clam-shaped dimeric assembly; four EF-hands of each KChIP1 form the shell, and the H10 helix of KChIP1 and α1 helix of Kv4.2 mediate the interaction, structurally analogous to calmodulin–target interactions; site-specific mutagenesis of H10 and α1 abolishes Kv4.2 modulation by KChIP1.","method":"X-ray crystallography (2.0 Å); site-directed mutagenesis; functional electrophysiology","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 1 — crystal structure plus mutagenesis with functional validation in one study","pmids":["14980206"],"is_preprint":false},{"year":2005,"finding":"KChIP1 promotes traffic of Kv4.2 to the plasma membrane via a post-ER vesicular pathway that is COPI-dependent but not COPII-coated; EF-hand mutations in KChIP1 abolish channel traffic to the plasma membrane and trap channels on KChIP1-positive vesicles; in hippocampal neurons KChIP1 co-distributes with dendritic Golgi outposts, suggesting a role in local dendritic vesicular traffic.","method":"Confocal live-cell imaging; EF-hand mutagenesis; dominant-negative Sar1 GTPase to block COPII; co-localization with COPI/COPII markers; neuronal imaging","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (mutagenesis, dominant-negative trafficking block, co-localization, neuronal imaging) in one study","pmids":["16260497"],"is_preprint":false},{"year":2003,"finding":"KChIP1 is targeted to post-ER transport vesicles through N-terminal myristoylation; residues at positions 3, 7, and 9 of the myristoylation motif determine distinct intracellular targeting compared with other NCS proteins (hippocalcin, NCS-1); correct myristoylation and targeting of KChIP1 is required for efficient trafficking of Kv4.2 to the plasma membrane.","method":"GFP-variant fusion proteins expressed in HeLa cells; confocal imaging; site-directed mutagenesis of myristoylation motif residues; co-expression with ECFP-Kv4.2","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 — mutagenesis combined with live imaging and trafficking readout; multiple mutants tested","pmids":["14600268"],"is_preprint":false},{"year":2009,"finding":"A SNARE complex containing VAMP7 and Vti1a defines the non-conventional traffic pathway used by KChIP1/Kv4 channels to the cell surface; KChIP1-positive vesicles co-localize with Vti1a and VAMP7 but not with other ER–Golgi SNARE components; siRNA knockdown of Vti1a or VAMP7 specifically inhibits Kv4/KChIP1 traffic without affecting conventional VSVG traffic or KChIP2-mediated Kv4 traffic.","method":"siRNA knockdown of SNARE proteins; co-localization imaging; surface expression assays in HeLa and Neuro2A cells; comparison with VSVG and KChIP2 traffic controls","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 2 — reciprocal specificity controls (VSVG, KChIP2), two cell lines, siRNA knockdown of two SNARE proteins","pmids":["19138172"],"is_preprint":false},{"year":2003,"finding":"KChIP1 splice variant KChIP1b (containing an extra aromatic-residue-rich exon in the N-terminus) equally upregulates Kv4.2 current density but induces a slow component of recovery from inactivation (τ ≈ 1.2 s), opposite to KChIP1a which accelerates recovery (τ = 125 ms); KChIP1b enhances frequency-dependent accumulation of inactivation while KChIP1a reduces it.","method":"Cloning of splice variant; confocal imaging of co-expression; whole-cell electrophysiology in heterologous expression system","journal":"Molecular and cellular neurosciences","confidence":"Medium","confidence_rationale":"Tier 2 — clear functional contrast between splice variants with electrophysiology, but single lab","pmids":["14572458"],"is_preprint":false},{"year":2007,"finding":"Kv4.x channels associated with KChIP1 exhibit accelerated inactivation and unaffected recovery when exposed to elevated external K+, opposite to P/C-type inactivation in Kv1 channels; regulation depends on permeant ion entering the selectivity filter and acts through a single regulatory site (Kd ≈ 8 mM for K+); quantitative kinetic modeling shows elevated external K+ inhibits unstable closed states outside the main activation pathway, promoting preferential closed-state inactivation.","method":"Whole-cell and macroscopic voltage-clamp recordings; ion substitution experiments; global kinetic modeling over 210 mV range","journal":"Biophysical journal","confidence":"High","confidence_rationale":"Tier 1 — in vitro electrophysiology with multiple ion substitutions, quantitative global kinetic modeling, rigorous mechanistic analysis","pmids":["17951301"],"is_preprint":false},{"year":2008,"finding":"KChIP1 stabilizes the tetrameric assembly of Kv4.3 through a 'clamping' interaction at a second protein-protein interface; mutations disrupting this interface in KChIP1 (L39E-Y57A-K61A) or Kv4.3 (E70A-F73E) reduce surface expression; WT KChIP1 rescues trafficking of a tetramer-disrupting Kv4.3 mutant (C110A), but the KChIP1 triple mutant cannot, linking tetrameric assembly to channel trafficking.","method":"Confocal microscopy of EGFP-tagged Kv4.3 in COS-7 cells; site-directed mutagenesis; whole-cell current recordings in oocytes","journal":"Neurochemical research","confidence":"Medium","confidence_rationale":"Tier 2 — mutagenesis at defined interface residues with both imaging and electrophysiology readouts, single lab","pmids":["18401705"],"is_preprint":false},{"year":2009,"finding":"EF-hands 3 and 4 of KChIP1 are required for membrane anchorage and preferential binding to phosphatidylserine (PS); deletion of EF-hands 3 and 4 reduces lipid-binding capability and membrane association; PS enrichment enhances WT KChIP1 membrane binding and induces a structural change in KChIP1.","method":"Truncation mutagenesis; lipid-binding assays with phospholipid vesicles; digitonin permeabilization; CD spectroscopy","journal":"Journal of biosciences","confidence":"Medium","confidence_rationale":"Tier 3 — in vitro biochemical binding assays with mutagenesis; single lab, moderate mechanistic follow-up","pmids":["19550036"],"is_preprint":false},{"year":2005,"finding":"KChIP1 protein has functional Ca2+-binding domains (demonstrated by altered SDS-PAGE migration upon Ca2+ binding) and a myristoylation motif that targets it to secretory vesicles of the Golgi; mutation of both myristoylation sites redistributes KChIP1 throughout the cytoplasm.","method":"SDS-PAGE Ca2+-binding shift assay; GFP fusion protein localization; site-directed mutagenesis of myristoylation sites","journal":"Sheng li xue bao : [Acta physiologica Sinica]","confidence":"Medium","confidence_rationale":"Tier 3 — in vitro Ca2+-binding assay and mutagenesis with GFP imaging; single lab, limited mechanistic depth","pmids":["15968430"],"is_preprint":false},{"year":2010,"finding":"KChIP1 co-expression modulates Kv4.3 biophysical properties in HEK293 cells (faster recovery from inactivation, leftward shift of activation, faster rise time, slower decay); in hippocampal CA1 LM/RAD interneurons, KChIP1 siRNA knockdown slows recovery from inactivation of A-type K+ currents and increases firing frequency during suprathreshold depolarizations without affecting action potential waveform.","method":"Whole-cell patch-clamp in HEK293 cells and hippocampal slice cultures; siRNA knockdown with confirmation; comparison with KChIP1-negative CA1 pyramidal cells as specificity control","journal":"Neuroscience","confidence":"High","confidence_rationale":"Tier 2 — siRNA knockdown with cell-type specificity control, combined heterologous and native neuron electrophysiology, multiple orthogonal readouts","pmids":["21129448"],"is_preprint":false},{"year":2010,"finding":"KChIP1 is localized predominantly at GABAergic synapses of parvalbumin-positive neurons; forced expression in hippocampal neurons increases mIPSC frequency and reduces paired-pulse facilitation of autaptic IPSCs; genetic ablation of KChIP1 potentiates potassium current density in neurons and causes enhanced anxiety-like behavior in mice.","method":"Immunostaining and electron microscopy for synaptic localization; whole-cell recordings of mIPSCs and autaptic IPSCs in cultured hippocampal neurons; KChIP1 knockout mice; behavioral assays","journal":"Molecular brain","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (electrophysiology, KO mice, imaging, behavior) from single study with defined cellular and circuit-level phenotypes","pmids":["20678225"],"is_preprint":false},{"year":2009,"finding":"KChIP1 is expressed in a subpopulation of parvalbumin-positive GABAergic neurons; KChIP1-deficient mice show increased susceptibility to pentylenetetrazole-induced seizures, indicating a role in GABAergic inhibitory system function.","method":"In situ hybridization; immunostaining; KChIP1 knockout mice; pentylenetetrazole seizure assay","journal":"Acta biochimica et biophysica Sinica","confidence":"Medium","confidence_rationale":"Tier 2 — KO mice with defined pharmacological phenotype and localization data; single lab","pmids":["19352544"],"is_preprint":false},{"year":2014,"finding":"In Xenopus embryos, Kcnip1 acts as a Ca2+-dependent transcriptional repressor that binds Downstream Regulatory Element (DRE) sites; loss of kcnip1 function expands the neural plate through increased proliferation of neural progenitors and impairs anterior neural structure development.","method":"Loss-of-function (morpholino knockdown) in Xenopus embryos; DRE binding assay; Ca2+-dependent binding characterization; in situ hybridization; immunostaining","journal":"Biochimica et biophysica acta","confidence":"Medium","confidence_rationale":"Tier 2 — loss-of-function with defined proliferation phenotype and DNA-binding assay; Xenopus ortholog, mechanistically consistent with mammalian KChIP1 Ca2+-sensor role","pmids":["25499267"],"is_preprint":false},{"year":2014,"finding":"Inhibition of KCNIP1 increases glucose-dependent insulin secretion without affecting insulin gene transcription or cell apoptosis, indicating that KCNIP1 modulates insulin secretion.","method":"siRNA-mediated inhibition of KCNIP1 in pancreatic beta cells; glucose-stimulated insulin secretion assay; insulin gene transcription assay; cell viability assay","journal":"Genomics","confidence":"Medium","confidence_rationale":"Tier 2 — direct loss-of-function experiment with specific functional readouts; single lab","pmids":["24886904"],"is_preprint":false},{"year":2026,"finding":"KChIP1 splice variants (1a and 1b) induce a slow component of recovery from inactivation in all Kv4.x channels tested (Kv4.1, Kv4.2, Kv4.3 S, Kv4.3 L), persisting in ternary Kv4+DPP+KChIP1 complexes; KChIP1b strongly enhances P/C-type (selectivity filter) inactivation features that are normally vestigial in Kv4 channels, demonstrating that alternative splicing of KChIP1 shifts the inactivation mechanism.","method":"Two-electrode voltage-clamp in Xenopus oocytes; binary and ternary channel complex reconstitution; mechanistic analysis of inactivation type across multiple Kv4 subtypes and both splice variants","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 1 — in vitro reconstitution of binary and ternary complexes with mechanistic dissection; single recent study, not yet replicated","pmids":["41545534"],"is_preprint":false}],"current_model":"KCNIP1 (KChIP1) is an N-myristoylated, EF-hand Ca2+-binding auxiliary subunit that directly binds the N-terminal domain of Kv4 voltage-gated potassium channels (via its H10 helix interacting with the Kv4 α1 helix, as revealed by crystal structure), stabilizes their tetrameric assembly through a clamping mechanism, and traffics with them to the plasma membrane via a non-conventional COPI-dependent, COPII-independent vesicular pathway defined by the VAMP7/Vti1a SNARE complex; once at the surface, KChIP1 remodels Kv4 gating by promoting closed-state inactivation, accelerating recovery from inactivation, and — depending on splice variant — can additionally enhance P/C-type inactivation features, while in neurons KChIP1 localizes to GABAergic synapses of parvalbumin-positive interneurons where it regulates inhibitory transmission, potassium current density, and behavioral anxiety."},"narrative":{"teleology":[{"year":2001,"claim":"Establishing that KChIP1 is a functionally significant Kv4 modulator with subtype-specific effects resolved how a single auxiliary subunit could differentially tune distinct Kv4 channels, with the Kv4 N-terminus identified as the determinant of this specificity.","evidence":"Heterologous expression in Xenopus oocytes with Kv4.1/Kv4.2 N-terminus chimeras and electrophysiology","pmids":["11423117"],"confidence":"High","gaps":["Structural basis of N-terminal specificity not resolved","Native neuronal context not tested"]},{"year":2002,"claim":"Quantitative kinetic modeling established that KChIP1 primarily remodels Kv4 gating by impairing open-state inactivation and lowering the energy barrier for closed-state inactivation, rather than simply altering surface expression.","evidence":"Whole-oocyte and single-channel recordings of Kv4.1 and Kv4.3 with allosteric kinetic modeling","pmids":["11826158"],"confidence":"High","gaps":["Single-channel mechanism of closed-state inactivation promotion not fully resolved","Role of Ca²⁺ binding in gating modulation not addressed"]},{"year":2003,"claim":"Discovery that N-terminal myristoylation targets KChIP1 to post-ER transport vesicles and that splice variant KChIP1b reverses the recovery-from-inactivation phenotype revealed that both membrane targeting and alternative splicing diversify KChIP1 function.","evidence":"GFP-fusion mutagenesis in HeLa cells for myristoylation; cloning and electrophysiology of KChIP1b splice variant","pmids":["14600268","14572458"],"confidence":"High","gaps":["Lipid specificity of myristoylation-dependent targeting unknown","In vivo relevance of KChIP1b splice variant not tested"]},{"year":2004,"claim":"The crystal structure of the KChIP1–Kv4.2 complex at 2.0 Å resolved the molecular interface (H10 helix of KChIP1 contacting the α1 helix of Kv4.2), establishing a calmodulin-like recognition mechanism and enabling structure-guided mutagenesis.","evidence":"X-ray crystallography with site-directed mutagenesis and electrophysiological validation","pmids":["14980206"],"confidence":"High","gaps":["Full-length channel–KChIP1 complex structure not determined","How Ca²⁺ occupancy of EF-hands modulates the interface not resolved structurally"]},{"year":2005,"claim":"KChIP1 was shown to promote Kv4 surface delivery via a COPI-dependent but COPII-independent pathway, identifying an unconventional post-ER trafficking route and establishing that EF-hand integrity is required for this process.","evidence":"Dominant-negative Sar1 GTPase, COPI/COPII marker co-localization, EF-hand mutagenesis, and neuronal imaging","pmids":["16260497"],"confidence":"High","gaps":["Cargo recognition mechanism in COPI vesicles not identified","Whether route is neuron-specific or general not established"]},{"year":2007,"claim":"External K⁺ was found to accelerate inactivation of Kv4/KChIP1 complexes through a selectivity-filter mechanism distinct from classical P/C-type inactivation, revealing that permeant ions regulate closed-state inactivation in these complexes.","evidence":"Voltage-clamp with ion substitution experiments and global kinetic modeling","pmids":["17951301"],"confidence":"High","gaps":["Structural basis of the single K⁺ regulatory site not identified","Relevance to native neuronal firing conditions not tested"]},{"year":2008,"claim":"A second KChIP1–Kv4 protein–protein interface was identified that stabilizes tetrameric channel assembly and is required for surface trafficking, linking quaternary structure maintenance to the trafficking function of KChIP1.","evidence":"Site-directed mutagenesis at the clamping interface in COS-7 cells with confocal microscopy and oocyte electrophysiology","pmids":["18401705"],"confidence":"Medium","gaps":["No structural resolution of the clamping interface","Single lab; awaits independent confirmation"]},{"year":2009,"claim":"The SNARE complex defining the KChIP1-specific trafficking route was identified as VAMP7/Vti1a, with siRNA knockdown specifically blocking Kv4/KChIP1 but not conventional cargo or KChIP2-mediated traffic, establishing pathway specificity among KChIP family members.","evidence":"siRNA knockdown of VAMP7 and Vti1a in HeLa and Neuro2A cells with surface expression assays and VSVG/KChIP2 controls","pmids":["19138172"],"confidence":"High","gaps":["Direct physical interaction between KChIP1 vesicles and VAMP7/Vti1a not demonstrated biochemically","Cargo sorting signal on KChIP1 not identified"]},{"year":2009,"claim":"KChIP1 was localized to parvalbumin-positive GABAergic neurons and its genetic ablation increased seizure susceptibility, providing the first in vivo evidence that KChIP1 is required for normal inhibitory circuit function.","evidence":"KChIP1 knockout mice with in situ hybridization, immunostaining, and pentylenetetrazole seizure assay","pmids":["19352544"],"confidence":"Medium","gaps":["Molecular mechanism linking KChIP1 loss to seizure susceptibility not dissected","Single lab; behavioral battery limited to one assay"]},{"year":2010,"claim":"Comprehensive characterization in native neurons and knockout mice established that KChIP1 localizes to GABAergic synapses, regulates mIPSC frequency, potassium current density, and anxiety-like behavior, defining its circuit-level functions.","evidence":"Electron microscopy, electrophysiology in cultured neurons and slices, KChIP1 KO mice, siRNA knockdown in hippocampal interneurons, behavioral assays","pmids":["20678225","21129448"],"confidence":"High","gaps":["Mechanism by which KChIP1 at GABAergic synapses regulates inhibitory transmission beyond Kv4 modulation is unclear","Anxiety phenotype not mapped to specific brain regions"]},{"year":2014,"claim":"KChIP1 was shown to function as a Ca²⁺-dependent transcriptional repressor binding DRE sites, with loss of function expanding the neural plate through increased neural progenitor proliferation, and separately to modulate glucose-dependent insulin secretion in pancreatic beta cells.","evidence":"Morpholino knockdown in Xenopus embryos with DRE binding assays; siRNA knockdown of KCNIP1 in pancreatic beta cells with insulin secretion assay","pmids":["25499267","24886904"],"confidence":"Medium","gaps":["Transcriptional repression function not demonstrated in mammalian neurons","Mechanism of insulin secretion regulation not linked to specific channel or transcriptional targets","Xenopus findings require mammalian validation"]},{"year":2026,"claim":"Systematic reconstitution of binary and ternary Kv4/DPP/KChIP1 complexes revealed that KChIP1 splice variants shift the balance between N-type and P/C-type inactivation mechanisms, with KChIP1b strongly enhancing normally vestigial selectivity-filter inactivation in Kv4 channels.","evidence":"Two-electrode voltage-clamp in Xenopus oocytes with binary and ternary complex reconstitution across multiple Kv4 subtypes","pmids":["41545534"],"confidence":"Medium","gaps":["Structural basis for splice-variant-dependent inactivation shift unknown","Not yet replicated independently","Physiological relevance of enhanced P/C-type inactivation in native neurons not tested"]},{"year":null,"claim":"Key unresolved questions include how Ca²⁺ occupancy of KChIP1 EF-hands allosterically controls the gating and trafficking functions, the structural basis of the full-length Kv4/KChIP1 complex, the mechanism by which KChIP1 modulates GABAergic transmission at the synaptic level, and whether its transcriptional repressor function operates in mammalian neurons.","evidence":"","pmids":[],"confidence":"Low","gaps":["No full-length Kv4/KChIP1 cryo-EM or crystal structure","Ca²⁺-dependent conformational switching not resolved structurally","DRE-mediated transcriptional repression not validated in mammalian brain"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1,6,7,16]},{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[9]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[14]}],"localization":[{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[3,4,5,10]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[3,5,8]},{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[3,10]}],"pathway":[{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[11,12,13]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[3,4,5]},{"term_id":"R-HSA-382551","term_label":"Transport of small molecules","supporting_discovery_ids":[0,1,7]}],"complexes":["Kv4/KChIP1 binary complex","Kv4/DPP/KChIP1 ternary complex"],"partners":["KCND1","KCND2","KCND3","VAMP7","VTI1A"],"other_free_text":[]},"mechanistic_narrative":"KCNIP1 (KChIP1) is an N-myristoylated, EF-hand Ca²⁺-sensing auxiliary subunit of Kv4 voltage-gated potassium channels that regulates channel assembly, trafficking, and inactivation gating, with additional roles in GABAergic neurotransmission and neural development. KChIP1 binds the Kv4 N-terminal domain via its H10 helix, stabilizes tetrameric channel assembly through a clamping interaction, and promotes channel surface expression through a non-conventional COPI-dependent, COPII-independent vesicular pathway defined by the VAMP7/Vti1a SNARE complex [PMID:14980206, PMID:18401705, PMID:16260497, PMID:19138172]. At the biophysical level, KChIP1 accelerates recovery from inactivation, promotes closed-state inactivation, and—depending on splice variant—can enhance P/C-type inactivation features normally vestigial in Kv4 channels [PMID:11826158, PMID:14572458, PMID:41545534]. In neurons, KChIP1 localizes to GABAergic synapses of parvalbumin-positive interneurons where it regulates inhibitory synaptic transmission, A-type potassium current density, and seizure susceptibility, and its genetic ablation produces enhanced anxiety-like behavior in mice [PMID:20678225, PMID:19352544, PMID:21129448]."},"prefetch_data":{"uniprot":{"accession":"Q9NZI2","full_name":"A-type potassium channel modulatory protein KCNIP1","aliases":["Kv channel-interacting protein 1","KChIP1","Potassium channel-interacting protein 1","Vesicle APC-binding protein"],"length_aa":227,"mass_kda":26.8,"function":"Regulatory subunit of Kv4/D (Shal)-type voltage-gated rapidly inactivating A-type potassium channels (PubMed:10676964, PubMed:11423117, PubMed:17187064, PubMed:34552243, PubMed:34997220). Regulates channel density, inactivation kinetics and rate of recovery from inactivation in a calcium-dependent and isoform-specific manner (PubMed:10676964, PubMed:11423117, PubMed:17187064, PubMed:34552243, PubMed:34997220). In vitro, modulates KCND1/Kv4.1 and KCND2/Kv4.2 currents (PubMed:34552243). Increases the presence of KCND2 at the cell surface (PubMed:12829703)","subcellular_location":"Cell membrane; Cytoplasm; Cell projection, dendrite","url":"https://www.uniprot.org/uniprotkb/Q9NZI2/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/KCNIP1","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/KCNIP1","total_profiled":1310},"omim":[{"mim_id":"614316","title":"VESICLE TRANSPORT THROUGH INTERACTION WITH T-SNARES 1A; VTI1A","url":"https://www.omim.org/entry/614316"},{"mim_id":"608182","title":"POTASSIUM CHANNEL-INTERACTING PROTEIN 4","url":"https://www.omim.org/entry/608182"},{"mim_id":"605410","title":"POTASSIUM VOLTAGE-GATED CHANNEL, SHAL-RELATED SUBFAMILY, MEMBER 2; KCND2","url":"https://www.omim.org/entry/605410"},{"mim_id":"604662","title":"POTASSIUM CHANNEL-INTERACTING PROTEIN 3; KCNIP3","url":"https://www.omim.org/entry/604662"},{"mim_id":"604660","title":"POTASSIUM CHANNEL-INTERACTING PROTEIN 1; KCNIP1","url":"https://www.omim.org/entry/604660"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Vesicles","reliability":"Approved"}],"tissue_specificity":"Group enriched","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"brain","ntpm":52.1},{"tissue":"epididymis","ntpm":20.4}],"url":"https://www.proteinatlas.org/search/KCNIP1"},"hgnc":{"alias_symbol":["KCHIP1"],"prev_symbol":[]},"alphafold":{"accession":"Q9NZI2","domains":[{"cath_id":"1.10.238.10","chopping":"48-131","consensus_level":"medium","plddt":87.627,"start":48,"end":131},{"cath_id":"1.10.238.10","chopping":"134-227","consensus_level":"medium","plddt":81.2073,"start":134,"end":227}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9NZI2","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9NZI2-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9NZI2-F1-predicted_aligned_error_v6.png","plddt_mean":78.19},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=KCNIP1","jax_strain_url":"https://www.jax.org/strain/search?query=KCNIP1"},"sequence":{"accession":"Q9NZI2","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9NZI2.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9NZI2/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9NZI2"}},"corpus_meta":[{"pmid":"11826158","id":"PMC_11826158","title":"Remodelling inactivation gating of Kv4 channels by KChIP1, a small-molecular-weight calcium-binding protein.","date":"2002","source":"The Journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/11826158","citation_count":117,"is_preprint":false},{"pmid":"14980206","id":"PMC_14980206","title":"Structural insights into the functional interaction of KChIP1 with Shal-type K(+) channels.","date":"2004","source":"Neuron","url":"https://pubmed.ncbi.nlm.nih.gov/14980206","citation_count":105,"is_preprint":false},{"pmid":"16260497","id":"PMC_16260497","title":"Traffic of Kv4 K+ channels mediated by KChIP1 is via a novel post-ER vesicular pathway.","date":"2005","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/16260497","citation_count":86,"is_preprint":false},{"pmid":"14600268","id":"PMC_14600268","title":"Residues within the myristoylation motif determine intracellular targeting of the neuronal Ca2+ sensor protein KChIP1 to post-ER transport vesicles and traffic of Kv4 K+ channels.","date":"2003","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/14600268","citation_count":55,"is_preprint":false},{"pmid":"19138172","id":"PMC_19138172","title":"A VAMP7/Vti1a SNARE complex distinguishes a non-conventional traffic route to the cell surface used by KChIP1 and Kv4 potassium channels.","date":"2009","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/19138172","citation_count":40,"is_preprint":false},{"pmid":"11423117","id":"PMC_11423117","title":"Different effects of the Ca(2+)-binding protein, KChIP1, on two Kv4 subfamily members, Kv4.1 and Kv4.2.","date":"2001","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/11423117","citation_count":34,"is_preprint":false},{"pmid":"26831368","id":"PMC_26831368","title":"Genome-wide screening identifies a KCNIP1 copy number variant as a genetic predictor for atrial fibrillation.","date":"2016","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/26831368","citation_count":34,"is_preprint":false},{"pmid":"14572458","id":"PMC_14572458","title":"Differential modulation of Kv4 kinetics by KCHIP1 splice variants.","date":"2003","source":"Molecular and cellular neurosciences","url":"https://pubmed.ncbi.nlm.nih.gov/14572458","citation_count":29,"is_preprint":false},{"pmid":"19350670","id":"PMC_19350670","title":"Complete 3D visualization of primate striosomes by KChIP1 immunostaining.","date":"2009","source":"The Journal of comparative neurology","url":"https://pubmed.ncbi.nlm.nih.gov/19350670","citation_count":29,"is_preprint":false},{"pmid":"17951301","id":"PMC_17951301","title":"Mechanism of the modulation of Kv4:KChIP-1 channels by external K+.","date":"2007","source":"Biophysical journal","url":"https://pubmed.ncbi.nlm.nih.gov/17951301","citation_count":29,"is_preprint":false},{"pmid":"11976919","id":"PMC_11976919","title":"Functional interaction between KChIP1 and GFP-fused Kv4.3L co-expressed in HEK293 cells.","date":"2002","source":"Pflugers Archiv : European journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/11976919","citation_count":20,"is_preprint":false},{"pmid":"21129448","id":"PMC_21129448","title":"KChIP1 modulation of Kv4.3-mediated A-type K(+) currents and repetitive firing in hippocampal interneurons.","date":"2010","source":"Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/21129448","citation_count":20,"is_preprint":false},{"pmid":"19352544","id":"PMC_19352544","title":"KChIP1: a potential modulator to GABAergic system.","date":"2009","source":"Acta biochimica et biophysica Sinica","url":"https://pubmed.ncbi.nlm.nih.gov/19352544","citation_count":20,"is_preprint":false},{"pmid":"18401705","id":"PMC_18401705","title":"Enhanced trafficking of tetrameric Kv4.3 channels by KChIP1 clamping.","date":"2008","source":"Neurochemical research","url":"https://pubmed.ncbi.nlm.nih.gov/18401705","citation_count":18,"is_preprint":false},{"pmid":"20678225","id":"PMC_20678225","title":"Roles of KChIP1 in the regulation of GABA-mediated transmission and behavioral anxiety.","date":"2010","source":"Molecular brain","url":"https://pubmed.ncbi.nlm.nih.gov/20678225","citation_count":16,"is_preprint":false},{"pmid":"25499267","id":"PMC_25499267","title":"Kcnip1 a Ca²⁺-dependent transcriptional repressor regulates the size of the neural plate in Xenopus.","date":"2014","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/25499267","citation_count":14,"is_preprint":false},{"pmid":"12612050","id":"PMC_12612050","title":"KChIP1 and frequenin modify shal-evoked potassium currents in pyloric neurons in the lobster stomatogastric ganglion.","date":"2002","source":"Journal of neurophysiology","url":"https://pubmed.ncbi.nlm.nih.gov/12612050","citation_count":14,"is_preprint":false},{"pmid":"24886904","id":"PMC_24886904","title":"Genome-wide copy number variation study reveals KCNIP1 as a modulator of insulin secretion.","date":"2014","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/24886904","citation_count":10,"is_preprint":false},{"pmid":"29176790","id":"PMC_29176790","title":"Attention-deficit/hyperactivity disorder associated with KChIP1 rs1541665 in Kv channels accessory proteins.","date":"2017","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/29176790","citation_count":8,"is_preprint":false},{"pmid":"25917026","id":"PMC_25917026","title":"Neuroprotective or neurotoxic effects of 4-aminopyridine mediated by KChIP1 regulation through adjustment of Kv 4.3 potassium channels expression and GABA-mediated transmission in primary hippocampal cells.","date":"2015","source":"Toxicology","url":"https://pubmed.ncbi.nlm.nih.gov/25917026","citation_count":6,"is_preprint":false},{"pmid":"31701097","id":"PMC_31701097","title":"In silico investigation of the interaction between the voltage-gated potassium channel Kv4.3 and its auxiliary protein KChIP1.","date":"2019","source":"Physical chemistry chemical physics : PCCP","url":"https://pubmed.ncbi.nlm.nih.gov/31701097","citation_count":2,"is_preprint":false},{"pmid":"29491224","id":"PMC_29491224","title":"Divergent patterns of genic copy number variation in KCNIP1 gene reveal risk locus of type 2 diabetes in Chinese population.","date":"2018","source":"Endocrine journal","url":"https://pubmed.ncbi.nlm.nih.gov/29491224","citation_count":2,"is_preprint":false},{"pmid":"19550036","id":"PMC_19550036","title":"Functional role of EF-hands 3 and 4 in membrane-binding of KChIP1.","date":"2009","source":"Journal of biosciences","url":"https://pubmed.ncbi.nlm.nih.gov/19550036","citation_count":2,"is_preprint":false},{"pmid":"15946496","id":"PMC_15946496","title":"[Discovery of a new splicing type of KCHIP1 gene].","date":"2005","source":"Ai zheng = Aizheng = Chinese journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/15946496","citation_count":2,"is_preprint":false},{"pmid":"15968430","id":"PMC_15968430","title":"Experimental study on the new significant function domains of KCHIP1 protein.","date":"2005","source":"Sheng li xue bao : [Acta physiologica Sinica]","url":"https://pubmed.ncbi.nlm.nih.gov/15968430","citation_count":1,"is_preprint":false},{"pmid":"41545534","id":"PMC_41545534","title":"KChIP1 splice variants modulate Kv4 channels by promoting P/C-type inactivation features.","date":"2026","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/41545534","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":13398,"output_tokens":4607,"usd":0.054649},"stage2":{"model":"claude-opus-4-6","input_tokens":8081,"output_tokens":3281,"usd":0.183645},"total_usd":0.238294,"stage1_batch_id":"msgbatch_01Mgbec4vM6c9vXht7JVJzss","stage2_batch_id":"msgbatch_01JkuuH5RB2BdJNsgnhjbC6s","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2002,\n      \"finding\": \"KChIP1 remodels inactivation gating of Kv4.1 and Kv4.3 channels by slowing the early phase of macroscopic inactivation, accelerating the late phase and closed-state inactivation, accelerating recovery from inactivation (3–5 fold), and promoting channel closing, without changing unitary conductance; an allosteric kinetic model shows KChIP1 mainly impairs open-state inactivation and lowers the energy barrier of closed-state inactivation.\",\n      \"method\": \"Whole-oocyte voltage-clamp and patch-clamp in Xenopus laevis oocytes; single-channel recordings; allosteric kinetic modeling\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — rigorous in vitro electrophysiology with single-channel recordings and quantitative kinetic modeling; replicated across two Kv4 subtypes\",\n      \"pmids\": [\"11826158\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"KChIP1 differentially modulates Kv4.1 and Kv4.2: it slows Kv4.2 inactivation but accelerates Kv4.1 inactivation, shifts activation voltage in opposite directions for the two channels, yet increases current amplitude and accelerates recovery from inactivation for both; Kv4 N-terminus chimeras demonstrate that differential effects are mediated by the Kv4 N-terminal domain.\",\n      \"method\": \"Heterologous expression in Xenopus oocytes; whole-cell electrophysiology; Kv4.1/Kv4.2 N-terminus chimeras\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro electrophysiology with chimera-based domain mapping\",\n      \"pmids\": [\"11423117\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Crystal structure (2.0 Å) of KChIP1 core domain in complex with the N-terminal fragment of Kv4.2 (Kv4.2N30) reveals a clam-shaped dimeric assembly; four EF-hands of each KChIP1 form the shell, and the H10 helix of KChIP1 and α1 helix of Kv4.2 mediate the interaction, structurally analogous to calmodulin–target interactions; site-specific mutagenesis of H10 and α1 abolishes Kv4.2 modulation by KChIP1.\",\n      \"method\": \"X-ray crystallography (2.0 Å); site-directed mutagenesis; functional electrophysiology\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structure plus mutagenesis with functional validation in one study\",\n      \"pmids\": [\"14980206\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"KChIP1 promotes traffic of Kv4.2 to the plasma membrane via a post-ER vesicular pathway that is COPI-dependent but not COPII-coated; EF-hand mutations in KChIP1 abolish channel traffic to the plasma membrane and trap channels on KChIP1-positive vesicles; in hippocampal neurons KChIP1 co-distributes with dendritic Golgi outposts, suggesting a role in local dendritic vesicular traffic.\",\n      \"method\": \"Confocal live-cell imaging; EF-hand mutagenesis; dominant-negative Sar1 GTPase to block COPII; co-localization with COPI/COPII markers; neuronal imaging\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (mutagenesis, dominant-negative trafficking block, co-localization, neuronal imaging) in one study\",\n      \"pmids\": [\"16260497\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"KChIP1 is targeted to post-ER transport vesicles through N-terminal myristoylation; residues at positions 3, 7, and 9 of the myristoylation motif determine distinct intracellular targeting compared with other NCS proteins (hippocalcin, NCS-1); correct myristoylation and targeting of KChIP1 is required for efficient trafficking of Kv4.2 to the plasma membrane.\",\n      \"method\": \"GFP-variant fusion proteins expressed in HeLa cells; confocal imaging; site-directed mutagenesis of myristoylation motif residues; co-expression with ECFP-Kv4.2\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — mutagenesis combined with live imaging and trafficking readout; multiple mutants tested\",\n      \"pmids\": [\"14600268\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"A SNARE complex containing VAMP7 and Vti1a defines the non-conventional traffic pathway used by KChIP1/Kv4 channels to the cell surface; KChIP1-positive vesicles co-localize with Vti1a and VAMP7 but not with other ER–Golgi SNARE components; siRNA knockdown of Vti1a or VAMP7 specifically inhibits Kv4/KChIP1 traffic without affecting conventional VSVG traffic or KChIP2-mediated Kv4 traffic.\",\n      \"method\": \"siRNA knockdown of SNARE proteins; co-localization imaging; surface expression assays in HeLa and Neuro2A cells; comparison with VSVG and KChIP2 traffic controls\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal specificity controls (VSVG, KChIP2), two cell lines, siRNA knockdown of two SNARE proteins\",\n      \"pmids\": [\"19138172\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"KChIP1 splice variant KChIP1b (containing an extra aromatic-residue-rich exon in the N-terminus) equally upregulates Kv4.2 current density but induces a slow component of recovery from inactivation (τ ≈ 1.2 s), opposite to KChIP1a which accelerates recovery (τ = 125 ms); KChIP1b enhances frequency-dependent accumulation of inactivation while KChIP1a reduces it.\",\n      \"method\": \"Cloning of splice variant; confocal imaging of co-expression; whole-cell electrophysiology in heterologous expression system\",\n      \"journal\": \"Molecular and cellular neurosciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clear functional contrast between splice variants with electrophysiology, but single lab\",\n      \"pmids\": [\"14572458\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Kv4.x channels associated with KChIP1 exhibit accelerated inactivation and unaffected recovery when exposed to elevated external K+, opposite to P/C-type inactivation in Kv1 channels; regulation depends on permeant ion entering the selectivity filter and acts through a single regulatory site (Kd ≈ 8 mM for K+); quantitative kinetic modeling shows elevated external K+ inhibits unstable closed states outside the main activation pathway, promoting preferential closed-state inactivation.\",\n      \"method\": \"Whole-cell and macroscopic voltage-clamp recordings; ion substitution experiments; global kinetic modeling over 210 mV range\",\n      \"journal\": \"Biophysical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro electrophysiology with multiple ion substitutions, quantitative global kinetic modeling, rigorous mechanistic analysis\",\n      \"pmids\": [\"17951301\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"KChIP1 stabilizes the tetrameric assembly of Kv4.3 through a 'clamping' interaction at a second protein-protein interface; mutations disrupting this interface in KChIP1 (L39E-Y57A-K61A) or Kv4.3 (E70A-F73E) reduce surface expression; WT KChIP1 rescues trafficking of a tetramer-disrupting Kv4.3 mutant (C110A), but the KChIP1 triple mutant cannot, linking tetrameric assembly to channel trafficking.\",\n      \"method\": \"Confocal microscopy of EGFP-tagged Kv4.3 in COS-7 cells; site-directed mutagenesis; whole-cell current recordings in oocytes\",\n      \"journal\": \"Neurochemical research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — mutagenesis at defined interface residues with both imaging and electrophysiology readouts, single lab\",\n      \"pmids\": [\"18401705\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"EF-hands 3 and 4 of KChIP1 are required for membrane anchorage and preferential binding to phosphatidylserine (PS); deletion of EF-hands 3 and 4 reduces lipid-binding capability and membrane association; PS enrichment enhances WT KChIP1 membrane binding and induces a structural change in KChIP1.\",\n      \"method\": \"Truncation mutagenesis; lipid-binding assays with phospholipid vesicles; digitonin permeabilization; CD spectroscopy\",\n      \"journal\": \"Journal of biosciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — in vitro biochemical binding assays with mutagenesis; single lab, moderate mechanistic follow-up\",\n      \"pmids\": [\"19550036\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"KChIP1 protein has functional Ca2+-binding domains (demonstrated by altered SDS-PAGE migration upon Ca2+ binding) and a myristoylation motif that targets it to secretory vesicles of the Golgi; mutation of both myristoylation sites redistributes KChIP1 throughout the cytoplasm.\",\n      \"method\": \"SDS-PAGE Ca2+-binding shift assay; GFP fusion protein localization; site-directed mutagenesis of myristoylation sites\",\n      \"journal\": \"Sheng li xue bao : [Acta physiologica Sinica]\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — in vitro Ca2+-binding assay and mutagenesis with GFP imaging; single lab, limited mechanistic depth\",\n      \"pmids\": [\"15968430\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"KChIP1 co-expression modulates Kv4.3 biophysical properties in HEK293 cells (faster recovery from inactivation, leftward shift of activation, faster rise time, slower decay); in hippocampal CA1 LM/RAD interneurons, KChIP1 siRNA knockdown slows recovery from inactivation of A-type K+ currents and increases firing frequency during suprathreshold depolarizations without affecting action potential waveform.\",\n      \"method\": \"Whole-cell patch-clamp in HEK293 cells and hippocampal slice cultures; siRNA knockdown with confirmation; comparison with KChIP1-negative CA1 pyramidal cells as specificity control\",\n      \"journal\": \"Neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — siRNA knockdown with cell-type specificity control, combined heterologous and native neuron electrophysiology, multiple orthogonal readouts\",\n      \"pmids\": [\"21129448\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"KChIP1 is localized predominantly at GABAergic synapses of parvalbumin-positive neurons; forced expression in hippocampal neurons increases mIPSC frequency and reduces paired-pulse facilitation of autaptic IPSCs; genetic ablation of KChIP1 potentiates potassium current density in neurons and causes enhanced anxiety-like behavior in mice.\",\n      \"method\": \"Immunostaining and electron microscopy for synaptic localization; whole-cell recordings of mIPSCs and autaptic IPSCs in cultured hippocampal neurons; KChIP1 knockout mice; behavioral assays\",\n      \"journal\": \"Molecular brain\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (electrophysiology, KO mice, imaging, behavior) from single study with defined cellular and circuit-level phenotypes\",\n      \"pmids\": [\"20678225\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"KChIP1 is expressed in a subpopulation of parvalbumin-positive GABAergic neurons; KChIP1-deficient mice show increased susceptibility to pentylenetetrazole-induced seizures, indicating a role in GABAergic inhibitory system function.\",\n      \"method\": \"In situ hybridization; immunostaining; KChIP1 knockout mice; pentylenetetrazole seizure assay\",\n      \"journal\": \"Acta biochimica et biophysica Sinica\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — KO mice with defined pharmacological phenotype and localization data; single lab\",\n      \"pmids\": [\"19352544\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"In Xenopus embryos, Kcnip1 acts as a Ca2+-dependent transcriptional repressor that binds Downstream Regulatory Element (DRE) sites; loss of kcnip1 function expands the neural plate through increased proliferation of neural progenitors and impairs anterior neural structure development.\",\n      \"method\": \"Loss-of-function (morpholino knockdown) in Xenopus embryos; DRE binding assay; Ca2+-dependent binding characterization; in situ hybridization; immunostaining\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function with defined proliferation phenotype and DNA-binding assay; Xenopus ortholog, mechanistically consistent with mammalian KChIP1 Ca2+-sensor role\",\n      \"pmids\": [\"25499267\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Inhibition of KCNIP1 increases glucose-dependent insulin secretion without affecting insulin gene transcription or cell apoptosis, indicating that KCNIP1 modulates insulin secretion.\",\n      \"method\": \"siRNA-mediated inhibition of KCNIP1 in pancreatic beta cells; glucose-stimulated insulin secretion assay; insulin gene transcription assay; cell viability assay\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct loss-of-function experiment with specific functional readouts; single lab\",\n      \"pmids\": [\"24886904\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"KChIP1 splice variants (1a and 1b) induce a slow component of recovery from inactivation in all Kv4.x channels tested (Kv4.1, Kv4.2, Kv4.3 S, Kv4.3 L), persisting in ternary Kv4+DPP+KChIP1 complexes; KChIP1b strongly enhances P/C-type (selectivity filter) inactivation features that are normally vestigial in Kv4 channels, demonstrating that alternative splicing of KChIP1 shifts the inactivation mechanism.\",\n      \"method\": \"Two-electrode voltage-clamp in Xenopus oocytes; binary and ternary channel complex reconstitution; mechanistic analysis of inactivation type across multiple Kv4 subtypes and both splice variants\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 — in vitro reconstitution of binary and ternary complexes with mechanistic dissection; single recent study, not yet replicated\",\n      \"pmids\": [\"41545534\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"KCNIP1 (KChIP1) is an N-myristoylated, EF-hand Ca2+-binding auxiliary subunit that directly binds the N-terminal domain of Kv4 voltage-gated potassium channels (via its H10 helix interacting with the Kv4 α1 helix, as revealed by crystal structure), stabilizes their tetrameric assembly through a clamping mechanism, and traffics with them to the plasma membrane via a non-conventional COPI-dependent, COPII-independent vesicular pathway defined by the VAMP7/Vti1a SNARE complex; once at the surface, KChIP1 remodels Kv4 gating by promoting closed-state inactivation, accelerating recovery from inactivation, and — depending on splice variant — can additionally enhance P/C-type inactivation features, while in neurons KChIP1 localizes to GABAergic synapses of parvalbumin-positive interneurons where it regulates inhibitory transmission, potassium current density, and behavioral anxiety.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"KCNIP1 (KChIP1) is an N-myristoylated, EF-hand Ca²⁺-sensing auxiliary subunit of Kv4 voltage-gated potassium channels that regulates channel assembly, trafficking, and inactivation gating, with additional roles in GABAergic neurotransmission and neural development. KChIP1 binds the Kv4 N-terminal domain via its H10 helix, stabilizes tetrameric channel assembly through a clamping interaction, and promotes channel surface expression through a non-conventional COPI-dependent, COPII-independent vesicular pathway defined by the VAMP7/Vti1a SNARE complex [PMID:14980206, PMID:18401705, PMID:16260497, PMID:19138172]. At the biophysical level, KChIP1 accelerates recovery from inactivation, promotes closed-state inactivation, and—depending on splice variant—can enhance P/C-type inactivation features normally vestigial in Kv4 channels [PMID:11826158, PMID:14572458, PMID:41545534]. In neurons, KChIP1 localizes to GABAergic synapses of parvalbumin-positive interneurons where it regulates inhibitory synaptic transmission, A-type potassium current density, and seizure susceptibility, and its genetic ablation produces enhanced anxiety-like behavior in mice [PMID:20678225, PMID:19352544, PMID:21129448].\",\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"Establishing that KChIP1 is a functionally significant Kv4 modulator with subtype-specific effects resolved how a single auxiliary subunit could differentially tune distinct Kv4 channels, with the Kv4 N-terminus identified as the determinant of this specificity.\",\n      \"evidence\": \"Heterologous expression in Xenopus oocytes with Kv4.1/Kv4.2 N-terminus chimeras and electrophysiology\",\n      \"pmids\": [\"11423117\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of N-terminal specificity not resolved\", \"Native neuronal context not tested\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Quantitative kinetic modeling established that KChIP1 primarily remodels Kv4 gating by impairing open-state inactivation and lowering the energy barrier for closed-state inactivation, rather than simply altering surface expression.\",\n      \"evidence\": \"Whole-oocyte and single-channel recordings of Kv4.1 and Kv4.3 with allosteric kinetic modeling\",\n      \"pmids\": [\"11826158\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Single-channel mechanism of closed-state inactivation promotion not fully resolved\", \"Role of Ca²⁺ binding in gating modulation not addressed\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Discovery that N-terminal myristoylation targets KChIP1 to post-ER transport vesicles and that splice variant KChIP1b reverses the recovery-from-inactivation phenotype revealed that both membrane targeting and alternative splicing diversify KChIP1 function.\",\n      \"evidence\": \"GFP-fusion mutagenesis in HeLa cells for myristoylation; cloning and electrophysiology of KChIP1b splice variant\",\n      \"pmids\": [\"14600268\", \"14572458\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Lipid specificity of myristoylation-dependent targeting unknown\", \"In vivo relevance of KChIP1b splice variant not tested\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"The crystal structure of the KChIP1–Kv4.2 complex at 2.0 Å resolved the molecular interface (H10 helix of KChIP1 contacting the α1 helix of Kv4.2), establishing a calmodulin-like recognition mechanism and enabling structure-guided mutagenesis.\",\n      \"evidence\": \"X-ray crystallography with site-directed mutagenesis and electrophysiological validation\",\n      \"pmids\": [\"14980206\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full-length channel–KChIP1 complex structure not determined\", \"How Ca²⁺ occupancy of EF-hands modulates the interface not resolved structurally\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"KChIP1 was shown to promote Kv4 surface delivery via a COPI-dependent but COPII-independent pathway, identifying an unconventional post-ER trafficking route and establishing that EF-hand integrity is required for this process.\",\n      \"evidence\": \"Dominant-negative Sar1 GTPase, COPI/COPII marker co-localization, EF-hand mutagenesis, and neuronal imaging\",\n      \"pmids\": [\"16260497\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Cargo recognition mechanism in COPI vesicles not identified\", \"Whether route is neuron-specific or general not established\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"External K⁺ was found to accelerate inactivation of Kv4/KChIP1 complexes through a selectivity-filter mechanism distinct from classical P/C-type inactivation, revealing that permeant ions regulate closed-state inactivation in these complexes.\",\n      \"evidence\": \"Voltage-clamp with ion substitution experiments and global kinetic modeling\",\n      \"pmids\": [\"17951301\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of the single K⁺ regulatory site not identified\", \"Relevance to native neuronal firing conditions not tested\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"A second KChIP1–Kv4 protein–protein interface was identified that stabilizes tetrameric channel assembly and is required for surface trafficking, linking quaternary structure maintenance to the trafficking function of KChIP1.\",\n      \"evidence\": \"Site-directed mutagenesis at the clamping interface in COS-7 cells with confocal microscopy and oocyte electrophysiology\",\n      \"pmids\": [\"18401705\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural resolution of the clamping interface\", \"Single lab; awaits independent confirmation\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"The SNARE complex defining the KChIP1-specific trafficking route was identified as VAMP7/Vti1a, with siRNA knockdown specifically blocking Kv4/KChIP1 but not conventional cargo or KChIP2-mediated traffic, establishing pathway specificity among KChIP family members.\",\n      \"evidence\": \"siRNA knockdown of VAMP7 and Vti1a in HeLa and Neuro2A cells with surface expression assays and VSVG/KChIP2 controls\",\n      \"pmids\": [\"19138172\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct physical interaction between KChIP1 vesicles and VAMP7/Vti1a not demonstrated biochemically\", \"Cargo sorting signal on KChIP1 not identified\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"KChIP1 was localized to parvalbumin-positive GABAergic neurons and its genetic ablation increased seizure susceptibility, providing the first in vivo evidence that KChIP1 is required for normal inhibitory circuit function.\",\n      \"evidence\": \"KChIP1 knockout mice with in situ hybridization, immunostaining, and pentylenetetrazole seizure assay\",\n      \"pmids\": [\"19352544\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular mechanism linking KChIP1 loss to seizure susceptibility not dissected\", \"Single lab; behavioral battery limited to one assay\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Comprehensive characterization in native neurons and knockout mice established that KChIP1 localizes to GABAergic synapses, regulates mIPSC frequency, potassium current density, and anxiety-like behavior, defining its circuit-level functions.\",\n      \"evidence\": \"Electron microscopy, electrophysiology in cultured neurons and slices, KChIP1 KO mice, siRNA knockdown in hippocampal interneurons, behavioral assays\",\n      \"pmids\": [\"20678225\", \"21129448\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which KChIP1 at GABAergic synapses regulates inhibitory transmission beyond Kv4 modulation is unclear\", \"Anxiety phenotype not mapped to specific brain regions\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"KChIP1 was shown to function as a Ca²⁺-dependent transcriptional repressor binding DRE sites, with loss of function expanding the neural plate through increased neural progenitor proliferation, and separately to modulate glucose-dependent insulin secretion in pancreatic beta cells.\",\n      \"evidence\": \"Morpholino knockdown in Xenopus embryos with DRE binding assays; siRNA knockdown of KCNIP1 in pancreatic beta cells with insulin secretion assay\",\n      \"pmids\": [\"25499267\", \"24886904\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Transcriptional repression function not demonstrated in mammalian neurons\", \"Mechanism of insulin secretion regulation not linked to specific channel or transcriptional targets\", \"Xenopus findings require mammalian validation\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Systematic reconstitution of binary and ternary Kv4/DPP/KChIP1 complexes revealed that KChIP1 splice variants shift the balance between N-type and P/C-type inactivation mechanisms, with KChIP1b strongly enhancing normally vestigial selectivity-filter inactivation in Kv4 channels.\",\n      \"evidence\": \"Two-electrode voltage-clamp in Xenopus oocytes with binary and ternary complex reconstitution across multiple Kv4 subtypes\",\n      \"pmids\": [\"41545534\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis for splice-variant-dependent inactivation shift unknown\", \"Not yet replicated independently\", \"Physiological relevance of enhanced P/C-type inactivation in native neurons not tested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include how Ca²⁺ occupancy of KChIP1 EF-hands allosterically controls the gating and trafficking functions, the structural basis of the full-length Kv4/KChIP1 complex, the mechanism by which KChIP1 modulates GABAergic transmission at the synaptic level, and whether its transcriptional repressor function operates in mammalian neurons.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No full-length Kv4/KChIP1 cryo-EM or crystal structure\", \"Ca²⁺-dependent conformational switching not resolved structurally\", \"DRE-mediated transcriptional repression not validated in mammalian brain\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 6, 7, 16]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [9]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [14]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [3, 4, 5, 10]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [3, 5, 8]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [3, 10]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0009536\", \"supporting_discovery_ids\": []},\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [11, 12, 13]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [3, 4, 5]},\n      {\"term_id\": \"R-HSA-382551\", \"supporting_discovery_ids\": [0, 1, 7]}\n    ],\n    \"complexes\": [\n      \"Kv4/KChIP1 binary complex\",\n      \"Kv4/DPP/KChIP1 ternary complex\"\n    ],\n    \"partners\": [\n      \"KCND1\",\n      \"KCND2\",\n      \"KCND3\",\n      \"VAMP7\",\n      \"VTI1A\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}