{"gene":"KCNC3","run_date":"2026-04-28T18:06:54","timeline":{"discoveries":[{"year":2006,"finding":"KCNC3 R420H mutation, located in the voltage-sensing domain, produces a non-functional channel subunit when expressed alone and exerts a dominant-negative effect when co-expressed with wild-type KCNC3 in Xenopus oocytes. KCNC3 F448L shifts the activation curve in the negative direction and slows channel closing.","method":"Xenopus oocyte heterologous expression with electrophysiology and co-expression experiments","journal":"Nature genetics","confidence":"High","confidence_rationale":"Tier 1 — in vitro electrophysiology with multiple mutants, replicated across subsequent studies","pmids":["16501573"],"is_preprint":false},{"year":2003,"finding":"Kv3.3 channels mediate N-type inactivation via an NH2-terminal domain; the rate and voltage dependence of inactivation differ significantly between cell expression systems (CHO vs HEK), with fast, voltage-dependent N-type inactivation requiring correct translation initiation from the first methionine start codon.","method":"Heterologous expression in CHO and HEK cells with mutagenesis of Kozak sequence and start codon","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — in vitro electrophysiology combined with start-site mutagenesis in two cell lines","pmids":["12923191"],"is_preprint":false},{"year":2008,"finding":"Protein kinase C (PKC) modulates Kv3.3 by increasing current amplitude and removing N-type inactivation; PKC acts via phosphorylation of serines at positions 3 and 9 within the N-terminal domain (first 78 amino acids), as deletion of this domain abolishes inactivation and mutagenesis of these serines affects PKC modulation.","method":"Heterologous expression in mammalian cells and Xenopus oocytes; N-terminal deletion and serine mutagenesis; PKC activator/inhibitor pharmacology; computer simulations","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — mutagenesis of candidate phosphorylation sites combined with pharmacological validation and heterologous expression","pmids":["18539595"],"is_preprint":false},{"year":2016,"finding":"The cytoplasmic C-terminus of Kv3.3 contains a proline-rich domain that recruits Arp2/3 to the plasma membrane via binding to Hax-1, forming a stable cortical actin network resistant to cytochalasin D; this actin network is required to prevent rapid N-type inactivation during short depolarizations. A disease-causing mutation within this proline-rich domain impairs Arp2/3 recruitment but not Hax-1 binding.","method":"Co-immunoprecipitation, biochemical pulldown, in vitro actin assays, electrophysiology, stem cell-derived neuron imaging","journal":"Cell","confidence":"High","confidence_rationale":"Tier 1–2 — multiple orthogonal methods including Co-IP, actin reconstitution, electrophysiology, and mutagenesis","pmids":["26997484"],"is_preprint":false},{"year":2021,"finding":"Kv3.3 channels directly bind and stimulate Tank Binding Kinase 1 (TBK1), which controls trafficking of membrane proteins into multivesicular bodies. TBK1 activity is required for Kv3.3 binding to its auxiliary subunit Hax-1. A disease-causing Kv3.3 mutation (G592R) greatly increases TBK1 stimulation, leading to Hax-1 degradation via multivesicular body/lysosomal trafficking, exosome release, caspase activation, and neuronal death.","method":"Co-immunoprecipitation, subcellular fractionation, biochemical assays, cell death assays, mouse model studies","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 — reciprocal Co-IP, multiple biochemical endpoints, in vivo validation with mouse model","pmids":["33741962"],"is_preprint":false},{"year":2021,"finding":"Ankyrin-R (AnkR) physically interacts with Kv3.3 and β3 spectrin, linking Kv3.3 to the spectrin-based cytoskeleton in Purkinje neurons; loss of AnkR reduces somatic membrane levels of Kv3.3 in Purkinje neurons and causes ataxia and progressive neurodegeneration.","method":"Co-immunoprecipitation, conditional knockout mice (Ank1 floxed × Nestin-Cre and Pcp2-Cre), immunofluorescence, western blot","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 — Co-IP with conditional KO validation and defined cellular/behavioral phenotype","pmids":["34785580"],"is_preprint":false},{"year":2008,"finding":"Kv3.3 channels at the Purkinje cell soma are necessary for generation of repetitive spikelets in the complex spike; spikelet generation occurs at axosomatic membranes, not dendrites. Kv3 and resurgent Na+ channels are coordinated to limit Na+ channel inactivation and enable rapid repetitive firing.","method":"Acute slice electrophysiology in Kv3.3 knockout mice, dual somatic-dendritic recordings, local pharmacology, computational modeling","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 — KO mouse with defined electrophysiological phenotype, spatial pharmacology, and modeling","pmids":["18256249"],"is_preprint":false},{"year":2008,"finding":"Purkinje-cell-restricted restoration of Kv3.3 in Kcnc3-null mice restores normal simple spike brevity and complex spike spikelets and rescues motor coordination (lateral deviation, beam slips), but not motor learning, demonstrating that Kv3.3 function in Purkinje cells is specifically required for motor coordination.","method":"Transgenic rescue (Purkinje-cell-targeted Kv3.3 re-expression), electrophysiology, behavioral assays in Kcnc3-null mice","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 — cell-type-specific genetic rescue with electrophysiological and behavioral readouts","pmids":["18448641"],"is_preprint":false},{"year":2009,"finding":"Rescue of motor coordination by Purkinje-cell-restricted Kv3.3 restoration requires Kcnc1 in the deep cerebellar nuclei (DCN); loss of Kcnc1 alleles in addition to Kcnc3 produces spike broadening and deceleration in DCN neurons, establishing that fast repolarization in both Purkinje cells and DCN neurons is necessary for normal motor coordination and gait patterning.","method":"Genetic epistasis with multiple allele combinations, Purkinje-cell-restricted transgenic rescue, DCN electrophysiology, gait analysis","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 — multi-allele epistasis with defined electrophysiological and behavioral phenotypes","pmids":["20016089"],"is_preprint":false},{"year":2003,"finding":"Combined loss of Kv3.1 and Kv3.3 in mice broadens parallel fiber action potentials, alters paired-pulse facilitation (PPF) at parallel fiber-Purkinje cell synapses in a gene-dose-dependent manner, increases activity-dependent presynaptic Ca2+ influx, and facilitates induction of metabotropic glutamate receptor-mediated EPSCs.","method":"Double and single knockout mice, electrophysiology (extracellular and intracellular recordings), Ca2+ manipulation, motor behavioral assays","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 — genetic KO with multiple electrophysiological and synaptic readouts","pmids":["12930807"],"is_preprint":false},{"year":2004,"finding":"Kv3.3 subunits are essential for the olivocerebellar system to generate harmaline-induced tremor; Kv3.3-single mutant mice lack harmaline tremor entirely and have approximately 100% broader Purkinje cell action potentials compared to wild-type or Kv3.1-single mutants.","method":"Kv3.3 and Kv3.1 single and double mutant mice, harmaline pharmacology, Purkinje cell electrophysiology, immunohistochemistry","journal":"The European journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 — KO with defined pharmacological challenge, electrophysiology, and behavioral phenotype","pmids":["15217387"],"is_preprint":false},{"year":2010,"finding":"Dendritic Kv3.3 channels in Purkinje cells oppose Ca2+ spike initiation and regulate propagation of electrical activity and Ca2+ influx in distal dendrites; Kv3.3 knockout mice show enhanced dendritic excitability and specifically elevated Ca2+ signals in distal dendrites following climbing fiber activation.","method":"Kv3.3 knockout mice, voltage clamp, local pharmacology, Ca2+ imaging throughout Purkinje cell dendritic tree","journal":"Journal of neurophysiology","confidence":"High","confidence_rationale":"Tier 2 — KO with multiple orthogonal methods (pharmacology, voltage clamp, Ca2+ imaging)","pmids":["20357073"],"is_preprint":false},{"year":2010,"finding":"KCNC3 R423H mutation exhibits dominant-negative properties similar to R420H (nonfunctional subunit suppressing current amplitude); however, R423H additionally produces altered gating when co-assembled with wild-type subunits (hyperpolarized activation shift, slower activation, modestly slower deactivation), while R420H-containing channels retain near-wild-type gating, explaining why R423H causes early-onset disease.","method":"Xenopus oocyte heterologous expression, electrophysiology of heteromeric channels with varying wild-type/mutant subunit ratios","journal":"Human mutation","confidence":"High","confidence_rationale":"Tier 1 — electrophysiology with heteromeric channel analysis distinguishing dual dominant-negative and gain-of-function gating effects","pmids":["19953606","22289912"],"is_preprint":false},{"year":2005,"finding":"A C-terminal domain of Kv3.3 directs channels to distal dendrites; the targeting domain includes a consensus sequence predicted to bind PDZ-type protein-protein interaction motifs, as demonstrated by retargeting experiments using in vivo viral injections in the electrosensory system.","method":"Immunohistochemistry, in vivo viral injection for recombinant channel expression, C-terminal domain deletion and retargeting experiments","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 — direct retargeting experiment in vivo, single lab","pmids":["16354911"],"is_preprint":false},{"year":2014,"finding":"KCNC3 R420H protein displays reduced complex glycan adducts compared to wild-type, is retained in the Golgi rather than trafficking to the plasma membrane (24% of wild-type surface expression by biotinylation), and causes altered Golgi and cellular morphology.","method":"Surface biotinylation, immunohistochemistry, electron microscopy, biochemical analysis of glycosylation","journal":"Neurobiology of disease","confidence":"Medium","confidence_rationale":"Tier 2 — multiple orthogonal methods (biotinylation, EM, glycan analysis), single lab","pmids":["25152487"],"is_preprint":false},{"year":2017,"finding":"KCNC3 R423H mutation results in altered glycosylation and aberrant retention in anterograde/endosomal vesicles, loss of plasma membrane expression, and aberrant intracellular retention of EGFR in mammalian cells; in Drosophila, co-expression of KCNC3 R423H with dEGFR rescues the eye phenotype, implicating indirect effects on EGFR signaling.","method":"Mammalian cell expression with immunofluorescence and electrophysiology, Drosophila genetic co-expression rescue experiments","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 — multiple methods (cell biology, Drosophila genetics) in single study","pmids":["28467418"],"is_preprint":false},{"year":2013,"finding":"Expression of mutant Kv3.3 R424H (equivalent to human R423H) in cultured cerebellar Purkinje cells via lentiviral vector decreases outward current density, broadens action potentials, elevates basal [Ca2+]i, impairs dendrite development, and causes cell death selectively in Purkinje cells; all rescued by blocking P/Q-type Ca2+ channels.","method":"Lentiviral expression in mouse cerebellar cultures, patch-clamp electrophysiology, Ca2+ imaging, pharmacological rescue","journal":"The Journal of physiology","confidence":"Medium","confidence_rationale":"Tier 2 — defined cellular phenotype with pharmacological rescue, single lab","pmids":["24218544"],"is_preprint":false},{"year":2018,"finding":"C-terminal proline deletion (p.Pro583_Pro585del) in KCNC3 causes normal membrane trafficking but slower channel inactivation and decreased sensitivity to actin depolymerizer latrunculin B, linking the C-terminal proline-rich domain to inactivation kinetics and actin-dependent channel regulation.","method":"Mammalian cell expression, electrophysiology, latrunculin B pharmacology, immunofluorescence","journal":"Cerebellum","confidence":"Medium","confidence_rationale":"Tier 2 — electrophysiology with pharmacological probe in cell expression system, single lab","pmids":["29949095"],"is_preprint":false},{"year":2022,"finding":"Deletion of Kv3.3 (but not Kv3.1) at the calyx of Held presynaptic terminal reduces presynaptic Kv3 channel immunolabelling, increases presynaptic AP duration, facilitates neurotransmitter release, and enhances short-term depression during high-frequency transmission; modeling showed increased vesicle release probability and accelerated activity-dependent vesicle replenishment in the Kv3.3 KO.","method":"Kv3.3 KO mice, electrophysiology, immunolabelling, computational modeling of synaptic transmission","journal":"eLife","confidence":"High","confidence_rationale":"Tier 2 — genetic KO with defined presynaptic electrophysiological phenotype, in vivo auditory recordings, and computational modeling","pmids":["35510987"],"is_preprint":false},{"year":2020,"finding":"In auditory brainstem, LSO neurons absolutely require Kv3.3 subunits for fast AP repolarization (half-width doubled in Kv3.3 KO) and to sustain high-frequency firing, while MNTB neurons can utilize either Kv3.1 or Kv3.3 subunits interchangeably; loss of Kv3.3 in LSO increases Ca2+ influx and AP failure rates.","method":"Kv3.3 and Kv3.1 knockout mice, patch-clamp electrophysiology, Ca2+ imaging, TEA pharmacology, western blot","journal":"The Journal of physiology","confidence":"High","confidence_rationale":"Tier 2 — subunit-specific KO with multiple orthogonal measurements distinguishing cell-type-specific roles","pmids":["32246836"],"is_preprint":false},{"year":2021,"finding":"Antisense oligonucleotides (ASOs) directed against Kcnc3 suppress Kv3.3 mRNA and protein in the cerebellum; in mice bearing the G592R SCA13 mutation, this reverses TBK1 overactivation, restores Hax-1 levels, reduces Cd63 (late endosome marker), and rescues rotarod motor performance, without affecting wild-type mice.","method":"Intracerebroventricular ASO infusion in wild-type and G592R knock-in mice, western blot, behavioral rotarod testing","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo ASO treatment with biochemical and behavioral endpoints, single lab","pmids":["34820911"],"is_preprint":false},{"year":2020,"finding":"In zebrafish, an infant-onset SCA13 mutation dramatically increases Purkinje cell excitability, stunts dendritic growth, impairs synaptogenesis, and causes rapid cell death during cerebellar development; reducing excitability increases early Purkinje cell survival. An adult-onset mutation reduces excitability during evoked high-frequency spiking without altering basal tonic firing, and does not cause developmental degeneration.","method":"Zebrafish in vivo electrophysiology, live imaging of Purkinje cell development, genetic loss-of-function with defined cellular phenotypes","journal":"eLife","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo zebrafish model with electrophysiology and imaging, single lab","pmids":["32644043"],"is_preprint":false},{"year":1992,"finding":"KCNC3 (Kv3.3) is encoded by at least two exons separated by ~3 kb of intervening sequence; the N-terminal 212 amino acids are encoded by a single exon and the hydrophobic core (from S1 transmembrane segment onward) by a separate exon. The gene was mapped to human chromosome 19.","method":"Genomic cloning, cDNA isolation, Southern blotting, chromosomal mapping","journal":"Genomics","confidence":"High","confidence_rationale":"Tier 1 — direct genomic and molecular characterization","pmids":["1740329"],"is_preprint":false},{"year":2022,"finding":"A missense mutation G434V in Kcnc3 (in the voltage sensor transmembrane domain) causes complete loss of voltage-gated conductance in electrophysiological recordings, broadening of action potentials, and decreased neuronal firing, resulting in spatial learning deficits in mice.","method":"CRISPR knock-in mouse, in vitro electrophysiology of mutant channel, behavioral fear conditioning and spatial learning assays","journal":"PNAS","confidence":"Medium","confidence_rationale":"Tier 2 — CRISPR KI with channel electrophysiology and behavioral phenotype, single lab","pmids":["35881790"],"is_preprint":false},{"year":2024,"finding":"A Kozak sequence variant (c.-6C>A) upstream of KCNC3 increases protein expression by enhanced translation initiation without affecting transcription rate, as demonstrated by luciferase assays, qPCR, and methylation analysis.","method":"Luciferase reporter assay, qPCR, methylation analysis in cell transfection system","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2 — multiple functional assays in single study","pmids":["39596509"],"is_preprint":false},{"year":2024,"finding":"The Kv3.3 E675K variant causes reduced current amplitude and more pronounced cumulative inactivation in Xenopus oocytes; both wild-type and E675K Kv3.3 inactivation is antagonized by increased extracellular potassium, suggesting a mechanism for potential therapeutic intervention.","method":"Voltage-clamp recordings in Xenopus oocytes, pharmacological manipulation of extracellular K+","journal":"Frontiers in cellular neuroscience","confidence":"Medium","confidence_rationale":"Tier 1 — electrophysiology in heterologous expression system, single lab","pmids":["39416683"],"is_preprint":false}],"current_model":"KCNC3/Kv3.3 is a voltage-gated Shaw-family K+ channel that rapidly activates at depolarized potentials and mediates fast action potential repolarization in fast-spiking neurons (especially cerebellar Purkinje cells and auditory brainstem neurons); its cytoplasmic C-terminus recruits Arp2/3 via Hax-1 to form a cortical actin network that prevents rapid N-type inactivation, while the N-terminus mediates PKC-regulated N-type inactivation (phosphorylation of Ser3/Ser9), Ankyrin-R links Kv3.3 to the β3 spectrin cytoskeleton at the Purkinje cell soma membrane, and Kv3.3 directly binds and stimulates TBK1 to regulate Hax-1 trafficking and neuronal survival—with disease-causing SCA13 mutations acting via dominant-negative current suppression (R420H, R423H), altered gating with negative activation shifts (F448L, R423H in heteromers), or disruption of the actin/TBK1/Hax-1 pathway (G592R, proline deletions), ultimately impairing high-frequency firing in cerebellar and auditory circuits."},"narrative":{"teleology":[{"year":1992,"claim":"The genomic organization and chromosomal location of KCNC3 were established, revealing a split-exon architecture encoding the N-terminal and transmembrane domains separately on chromosome 19, providing the molecular foundation for subsequent functional studies.","evidence":"Genomic cloning, cDNA isolation, Southern blotting, and chromosomal mapping","pmids":["1740329"],"confidence":"High","gaps":["No functional characterization of channel activity at this stage","Splice variant diversity not explored"]},{"year":2003,"claim":"The N-terminal domain was identified as the mediator of N-type inactivation, resolving how Kv3.3 can transition between sustained and inactivating modes; concurrently, Kv3.1/Kv3.3 double-knockout mice revealed that these subunits jointly control parallel fiber AP width and presynaptic calcium dynamics in the cerebellum.","evidence":"Start-codon and Kozak mutagenesis with electrophysiology in CHO/HEK cells; single and double KO mice with synaptic recordings","pmids":["12923191","12930807"],"confidence":"High","gaps":["Molecular identity of inactivation ball peptide not resolved","Relative contribution of Kv3.3 vs Kv3.1 at individual synapses unclear"]},{"year":2004,"claim":"Kv3.3, not Kv3.1, was shown to be the essential subunit for Purkinje cell AP repolarization and olivocerebellar tremor generation, establishing subunit-specific non-redundant roles in the cerebellar circuit.","evidence":"Kv3.3 and Kv3.1 single and double KO mice with harmaline tremor assay and Purkinje cell electrophysiology","pmids":["15217387"],"confidence":"High","gaps":["Mechanism of subunit-specific expression patterns in Purkinje cells unknown","Whether Kv3.3 homo- or heteromeric channels predominate in vivo unresolved"]},{"year":2005,"claim":"A C-terminal targeting domain containing a putative PDZ-binding motif was identified as directing Kv3.3 to distal dendrites, revealing that subcellular localization is encoded within the channel itself.","evidence":"In vivo viral expression with C-terminal deletion/retargeting in electrosensory lateral line lobe","pmids":["16354911"],"confidence":"Medium","gaps":["Identity of the interacting PDZ-domain protein not determined","Relevance to mammalian dendritic targeting not confirmed"]},{"year":2006,"claim":"The first SCA13-causing mutations were functionally characterized, showing that R420H acts as a dominant-negative non-conducting subunit while F448L shifts activation negatively, establishing two distinct pathogenic mechanisms for the same disease locus.","evidence":"Xenopus oocyte expression with electrophysiology and co-expression of wild-type/mutant subunits","pmids":["16501573"],"confidence":"High","gaps":["In vivo consequences of these mutations on Purkinje cell firing not yet tested","Whether heteromeric gating changes contribute to R420H pathogenesis unknown"]},{"year":2008,"claim":"PKC was shown to regulate N-type inactivation through phosphorylation of Ser3/Ser9, providing a signaling mechanism by which neuromodulators dynamically switch Kv3.3 between inactivating and sustained modes; simultaneously, Kv3.3 was proven essential for complex spike spikelet generation and motor coordination specifically within Purkinje cells via cell-type-specific rescue.","evidence":"Mutagenesis of Ser3/Ser9 with PKC pharmacology; Purkinje-cell-restricted transgenic rescue in Kcnc3 KO mice with electrophysiology and behavioral testing","pmids":["18539595","18256249","18448641"],"confidence":"High","gaps":["Physiological conditions triggering PKC-mediated modulation in vivo unknown","Why motor learning was not rescued by Purkinje cell Kv3.3 restoration remains unexplained"]},{"year":2009,"claim":"Genetic epistasis between Kv3.3 in Purkinje cells and Kv3.1 in deep cerebellar nuclei demonstrated that fast repolarization at multiple nodes of the cerebellar circuit is required for normal motor coordination, establishing a circuit-level requirement beyond single cell types.","evidence":"Multi-allele Kcnc1/Kcnc3 crosses with Purkinje-cell transgenic rescue, DCN electrophysiology, and gait analysis","pmids":["20016089"],"confidence":"High","gaps":["Specific Kv3 subunit composition in DCN neurons not defined","Contribution of mossy fiber inputs and other interneurons not addressed"]},{"year":2010,"claim":"Dendritic Kv3.3 channels were shown to oppose Ca²⁺ spike initiation in distal Purkinje cell dendrites, extending the functional role of Kv3.3 beyond somatic/axonal repolarization to include regulation of dendritic excitability and climbing fiber-evoked calcium signaling.","evidence":"Kv3.3 KO mice with voltage clamp, local pharmacology, and dendritic Ca²⁺ imaging","pmids":["20357073"],"confidence":"High","gaps":["Molecular basis for dendritic vs somatic Kv3.3 targeting not resolved","Functional impact on synaptic plasticity at climbing fiber synapses not tested"]},{"year":2010,"claim":"R423H was distinguished from R420H by its dual mechanism: both dominant-negative suppression and altered heteromeric channel gating (hyperpolarized activation, slowed kinetics), explaining the more severe early-onset SCA13 phenotype with R423H.","evidence":"Xenopus oocyte electrophysiology with defined wild-type/mutant subunit ratios","pmids":["19953606","22289912"],"confidence":"High","gaps":["Structural basis for why adjacent arginine mutations produce different gating effects unknown","In vivo confirmation of heteromeric gating shifts lacking"]},{"year":2013,"claim":"Mutant Kv3.3 (R424H) was shown to cause Purkinje cell death via calcium overload secondary to AP broadening, with rescue by P/Q-type calcium channel blockade, establishing a mechanistic link from channel dysfunction to neurodegeneration.","evidence":"Lentiviral expression of R424H in cultured Purkinje cells with electrophysiology, Ca²⁺ imaging, and pharmacological rescue","pmids":["24218544"],"confidence":"Medium","gaps":["Whether P/Q-type blockade rescues degeneration in vivo untested","Contribution of non-cell-autonomous mechanisms not evaluated"]},{"year":2016,"claim":"The C-terminal proline-rich domain was identified as an Arp2/3/Hax-1 recruitment platform that builds a cortical actin network preventing N-type inactivation during brief depolarizations, revealing a non-canonical channel function in cytoskeletal organization.","evidence":"Co-IP, pulldown, in vitro actin assays, electrophysiology, and stem cell-derived neuron imaging; disease mutation disrupts Arp2/3 but not Hax-1 binding","pmids":["26997484"],"confidence":"High","gaps":["Structural details of the proline-rich domain interaction with Hax-1 and Arp2/3 not resolved","Whether actin-dependent regulation operates in all Kv3.3-expressing neuron types unknown"]},{"year":2018,"claim":"A proline deletion (p.Pro583_Pro585del) in the C-terminal domain slowed inactivation and reduced actin-dependent regulation without impairing surface trafficking, providing finer dissection of how the proline-rich region controls gating through the actin cytoskeleton.","evidence":"Mammalian cell electrophysiology with latrunculin B pharmacology and immunofluorescence","pmids":["29949095"],"confidence":"Medium","gaps":["Whether this variant is pathogenic in humans not established","Direct biophysical mechanism linking actin to inactivation gate not resolved"]},{"year":2020,"claim":"Cell-type-specific knockout studies in auditory brainstem demonstrated that LSO neurons absolutely require Kv3.3 for fast repolarization while MNTB neurons can substitute Kv3.1, establishing differential subunit dependence across auditory nuclei.","evidence":"Kv3.3 and Kv3.1 KO mice with patch-clamp, Ca²⁺ imaging, and TEA pharmacology in LSO and MNTB","pmids":["32246836"],"confidence":"High","gaps":["Hearing phenotype in Kv3.3 KO mice not fully characterized","Whether Kv3.3 heteromerizes with Kv3.1 in these nuclei not determined"]},{"year":2021,"claim":"Kv3.3 was discovered to directly bind and activate TBK1, controlling Hax-1 trafficking through multivesicular bodies; the G592R SCA13 mutation hyperactivates TBK1, causing Hax-1 degradation, exosome release, and neuronal death—a non-conducting function distinct from ion permeation. ASO-mediated suppression of mutant Kv3.3 reversed TBK1 overactivation and rescued motor function in G592R mice.","evidence":"Reciprocal Co-IP, subcellular fractionation, cell death assays, mouse models; intracerebroventricular ASO with biochemical and rotarod endpoints","pmids":["33741962","34820911"],"confidence":"High","gaps":["Structural basis of Kv3.3-TBK1 interaction not determined","Whether TBK1 activation contributes to other SCA13 mutations unknown","Long-term therapeutic window of ASO approach not defined"]},{"year":2021,"claim":"Ankyrin-R was identified as the cytoskeletal anchor linking Kv3.3 to β3 spectrin at the Purkinje cell soma; loss of AnkR reduced somatic Kv3.3 levels and caused ataxia and neurodegeneration, establishing a somatic retention mechanism complementary to the C-terminal dendritic targeting signal.","evidence":"Co-IP, conditional AnkR KO (Nestin-Cre and Pcp2-Cre), immunofluorescence, behavioral phenotyping","pmids":["34785580"],"confidence":"High","gaps":["Binding interface between AnkR and Kv3.3 not mapped","Whether AnkR also anchors Kv3.3 outside the cerebellum unknown"]},{"year":2022,"claim":"Kv3.3 was shown to be the dominant presynaptic Kv3 subunit at the calyx of Held, where it constrains AP duration, limits neurotransmitter release, and supports faithful high-frequency transmission; a voltage-sensor mutation (G434V) separately confirmed that loss of Kv3.3 conductance impairs spatial learning.","evidence":"Kv3.3 KO mice with calyx electrophysiology and computational modeling; CRISPR G434V KI mice with behavioral testing","pmids":["35510987","35881790"],"confidence":"High","gaps":["Whether Kv3.3 loss at the calyx affects auditory processing in behaving animals not tested","Cognitive circuits dependent on Kv3.3 beyond cerebellum and auditory brainstem not mapped"]},{"year":2024,"claim":"Translational regulation of Kv3.3 was demonstrated via a Kozak sequence variant that increases protein expression, and the E675K C-terminal variant was shown to reduce current and enhance cumulative inactivation that is antagonized by elevated extracellular potassium.","evidence":"Luciferase reporter/qPCR assays for Kozak variant; Xenopus oocyte voltage-clamp for E675K with extracellular K⁺ manipulation","pmids":["39596509","39416683"],"confidence":"Medium","gaps":["In vivo relevance of Kozak variant to disease phenotype unresolved","Mechanism by which extracellular K⁺ antagonizes inactivation not clarified at structural level"]},{"year":null,"claim":"Key unresolved questions include the high-resolution structure of the Kv3.3 C-terminal signaling complex (Hax-1/Arp2/3/TBK1), the identity of PDZ-domain proteins mediating dendritic targeting, whether non-conducting functions of Kv3.3 contribute to pathogenesis across all SCA13 mutations, and the full extent of Kv3.3-dependent circuits beyond the cerebellum and auditory brainstem.","evidence":"","pmids":[],"confidence":"Low","gaps":["No high-resolution structure of Kv3.3 or its signaling complexes","PDZ-domain targeting partner unidentified","Relative contribution of conducting vs non-conducting functions to SCA13 pathogenesis not quantified"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005215","term_label":"transporter activity","supporting_discovery_ids":[0,1,2,6,18,19]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[3,4]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[3,5]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,3,5,14,18]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[3,4]}],"pathway":[{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[6,7,8,9,10,11,18,19]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[2,4]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[0,12,16,21]}],"complexes":[],"partners":["HAX1","TBK1","ANK1","SPTBN2","ACTR2"],"other_free_text":[]},"mechanistic_narrative":"KCNC3 encodes the voltage-gated potassium channel Kv3.3, a Shaw-family subunit that activates at depolarized potentials to mediate fast action potential repolarization in high-frequency-firing neurons, including cerebellar Purkinje cells, deep cerebellar nuclei neurons, and auditory brainstem neurons [PMID:18256249, PMID:32246836, PMID:35510987]. The channel undergoes N-type inactivation via its N-terminal domain, regulated by PKC phosphorylation of Ser3 and Ser9, while the cytoplasmic C-terminus recruits Hax-1 and Arp2/3 to assemble a cortical actin network that prevents rapid inactivation during brief depolarizations [PMID:12923191, PMID:18539595, PMID:26997484]. Kv3.3 also directly binds and stimulates TBK1 to control Hax-1 trafficking via multivesicular bodies, and is anchored at the Purkinje cell soma membrane through Ankyrin-R/β3-spectrin linkage [PMID:33741962, PMID:34785580]. Dominant mutations in KCNC3 cause spinocerebellar ataxia type 13 (SCA13) through mechanisms including dominant-negative current suppression (R420H, R423H), shifted voltage dependence of activation (F448L, R423H), and disruption of the C-terminal actin/TBK1 signaling axis (G592R), leading to impaired high-frequency firing, elevated intracellular calcium, and Purkinje cell degeneration [PMID:16501573, PMID:19953606, PMID:24218544, PMID:32644043]."},"prefetch_data":{"uniprot":{"accession":"Q14003","full_name":"Voltage-gated potassium channel KCNC3","aliases":["KSHIIID","Potassium voltage-gated channel subfamily C member 3","Voltage-gated potassium channel subunit Kv3.3"],"length_aa":757,"mass_kda":80.6,"function":"Voltage-gated potassium channel that plays an important role in the rapid repolarization of fast-firing brain neurons. The channel opens in response to the voltage difference across the membrane, forming a potassium-selective channel through which potassium ions pass in accordance with their electrochemical gradient. The channel displays rapid activation and inactivation kinetics (PubMed:10712820, PubMed:16501573, PubMed:19953606, PubMed:21479265, PubMed:22289912, PubMed:23734863, PubMed:25756792, PubMed:26997484). It plays a role in the regulation of the frequency, shape and duration of action potentials in Purkinje cells. Required for normal survival of cerebellar neurons, probably via its role in regulating the duration and frequency of action potentials that in turn regulate the activity of voltage-gated Ca(2+) channels and cellular Ca(2+) homeostasis (By similarity). Required for normal motor function (PubMed:16501573, PubMed:19953606, PubMed:21479265, PubMed:23734863, PubMed:25756792). Plays a role in the reorganization of the cortical actin cytoskeleton and the formation of actin veil structures in neuronal growth cones via its interaction with HAX1 and the Arp2/3 complex (PubMed:26997484)","subcellular_location":"Cell membrane; Presynaptic cell membrane; Perikaryon; Cell projection, axon; Cell projection, dendrite; Cell projection, dendritic spine membrane; Cytoplasm, cell cortex; Cytoplasm, cytoskeleton","url":"https://www.uniprot.org/uniprotkb/Q14003/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/KCNC3","classification":"Not Classified","n_dependent_lines":2,"n_total_lines":1208,"dependency_fraction":0.0016556291390728477},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/KCNC3","total_profiled":1310},"omim":[{"mim_id":"611907","title":"EPISODIC ATAXIA, TYPE 7; EA7","url":"https://www.omim.org/entry/611907"},{"mim_id":"605259","title":"SPINOCEREBELLAR ATAXIA 13; SCA13","url":"https://www.omim.org/entry/605259"},{"mim_id":"600235","title":"SODIUM VOLTAGE-GATED CHANNEL, BETA SUBUNIT 1; SCN1B","url":"https://www.omim.org/entry/600235"},{"mim_id":"176264","title":"POTASSIUM CHANNEL, VOLTAGE-GATED, SHAW-RELATED SUBFAMILY, MEMBER 3; KCNC3","url":"https://www.omim.org/entry/176264"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"brain","ntpm":56.7},{"tissue":"thyroid gland","ntpm":39.3}],"url":"https://www.proteinatlas.org/search/KCNC3"},"hgnc":{"alias_symbol":["Kv3.3"],"prev_symbol":["SCA13"]},"alphafold":{"accession":"Q14003","domains":[{"cath_id":"3.30.710.10","chopping":"90-202","consensus_level":"high","plddt":89.9364,"start":90,"end":202},{"cath_id":"1.20.120.350","chopping":"271-327_334-431","consensus_level":"high","plddt":83.6312,"start":271,"end":431},{"cath_id":"1.10.287.70","chopping":"437-555","consensus_level":"high","plddt":90.123,"start":437,"end":555}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q14003","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q14003-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q14003-F1-predicted_aligned_error_v6.png","plddt_mean":64.12},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=KCNC3","jax_strain_url":"https://www.jax.org/strain/search?query=KCNC3"},"sequence":{"accession":"Q14003","fasta_url":"https://rest.uniprot.org/uniprotkb/Q14003.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q14003/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q14003"}},"corpus_meta":[{"pmid":"16501573","id":"PMC_16501573","title":"Mutations 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KCNC3 F448L shifts the activation curve in the negative direction and slows channel closing.\",\n      \"method\": \"Xenopus oocyte heterologous expression with electrophysiology and co-expression experiments\",\n      \"journal\": \"Nature genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro electrophysiology with multiple mutants, replicated across subsequent studies\",\n      \"pmids\": [\"16501573\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Kv3.3 channels mediate N-type inactivation via an NH2-terminal domain; the rate and voltage dependence of inactivation differ significantly between cell expression systems (CHO vs HEK), with fast, voltage-dependent N-type inactivation requiring correct translation initiation from the first methionine start codon.\",\n      \"method\": \"Heterologous expression in CHO and HEK cells with mutagenesis of Kozak sequence and start codon\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro electrophysiology combined with start-site mutagenesis in two cell lines\",\n      \"pmids\": [\"12923191\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Protein kinase C (PKC) modulates Kv3.3 by increasing current amplitude and removing N-type inactivation; PKC acts via phosphorylation of serines at positions 3 and 9 within the N-terminal domain (first 78 amino acids), as deletion of this domain abolishes inactivation and mutagenesis of these serines affects PKC modulation.\",\n      \"method\": \"Heterologous expression in mammalian cells and Xenopus oocytes; N-terminal deletion and serine mutagenesis; PKC activator/inhibitor pharmacology; computer simulations\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — mutagenesis of candidate phosphorylation sites combined with pharmacological validation and heterologous expression\",\n      \"pmids\": [\"18539595\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"The cytoplasmic C-terminus of Kv3.3 contains a proline-rich domain that recruits Arp2/3 to the plasma membrane via binding to Hax-1, forming a stable cortical actin network resistant to cytochalasin D; this actin network is required to prevent rapid N-type inactivation during short depolarizations. A disease-causing mutation within this proline-rich domain impairs Arp2/3 recruitment but not Hax-1 binding.\",\n      \"method\": \"Co-immunoprecipitation, biochemical pulldown, in vitro actin assays, electrophysiology, stem cell-derived neuron imaging\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — multiple orthogonal methods including Co-IP, actin reconstitution, electrophysiology, and mutagenesis\",\n      \"pmids\": [\"26997484\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Kv3.3 channels directly bind and stimulate Tank Binding Kinase 1 (TBK1), which controls trafficking of membrane proteins into multivesicular bodies. TBK1 activity is required for Kv3.3 binding to its auxiliary subunit Hax-1. A disease-causing Kv3.3 mutation (G592R) greatly increases TBK1 stimulation, leading to Hax-1 degradation via multivesicular body/lysosomal trafficking, exosome release, caspase activation, and neuronal death.\",\n      \"method\": \"Co-immunoprecipitation, subcellular fractionation, biochemical assays, cell death assays, mouse model studies\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP, multiple biochemical endpoints, in vivo validation with mouse model\",\n      \"pmids\": [\"33741962\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Ankyrin-R (AnkR) physically interacts with Kv3.3 and β3 spectrin, linking Kv3.3 to the spectrin-based cytoskeleton in Purkinje neurons; loss of AnkR reduces somatic membrane levels of Kv3.3 in Purkinje neurons and causes ataxia and progressive neurodegeneration.\",\n      \"method\": \"Co-immunoprecipitation, conditional knockout mice (Ank1 floxed × Nestin-Cre and Pcp2-Cre), immunofluorescence, western blot\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP with conditional KO validation and defined cellular/behavioral phenotype\",\n      \"pmids\": [\"34785580\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Kv3.3 channels at the Purkinje cell soma are necessary for generation of repetitive spikelets in the complex spike; spikelet generation occurs at axosomatic membranes, not dendrites. Kv3 and resurgent Na+ channels are coordinated to limit Na+ channel inactivation and enable rapid repetitive firing.\",\n      \"method\": \"Acute slice electrophysiology in Kv3.3 knockout mice, dual somatic-dendritic recordings, local pharmacology, computational modeling\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — KO mouse with defined electrophysiological phenotype, spatial pharmacology, and modeling\",\n      \"pmids\": [\"18256249\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Purkinje-cell-restricted restoration of Kv3.3 in Kcnc3-null mice restores normal simple spike brevity and complex spike spikelets and rescues motor coordination (lateral deviation, beam slips), but not motor learning, demonstrating that Kv3.3 function in Purkinje cells is specifically required for motor coordination.\",\n      \"method\": \"Transgenic rescue (Purkinje-cell-targeted Kv3.3 re-expression), electrophysiology, behavioral assays in Kcnc3-null mice\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — cell-type-specific genetic rescue with electrophysiological and behavioral readouts\",\n      \"pmids\": [\"18448641\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Rescue of motor coordination by Purkinje-cell-restricted Kv3.3 restoration requires Kcnc1 in the deep cerebellar nuclei (DCN); loss of Kcnc1 alleles in addition to Kcnc3 produces spike broadening and deceleration in DCN neurons, establishing that fast repolarization in both Purkinje cells and DCN neurons is necessary for normal motor coordination and gait patterning.\",\n      \"method\": \"Genetic epistasis with multiple allele combinations, Purkinje-cell-restricted transgenic rescue, DCN electrophysiology, gait analysis\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multi-allele epistasis with defined electrophysiological and behavioral phenotypes\",\n      \"pmids\": [\"20016089\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Combined loss of Kv3.1 and Kv3.3 in mice broadens parallel fiber action potentials, alters paired-pulse facilitation (PPF) at parallel fiber-Purkinje cell synapses in a gene-dose-dependent manner, increases activity-dependent presynaptic Ca2+ influx, and facilitates induction of metabotropic glutamate receptor-mediated EPSCs.\",\n      \"method\": \"Double and single knockout mice, electrophysiology (extracellular and intracellular recordings), Ca2+ manipulation, motor behavioral assays\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO with multiple electrophysiological and synaptic readouts\",\n      \"pmids\": [\"12930807\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Kv3.3 subunits are essential for the olivocerebellar system to generate harmaline-induced tremor; Kv3.3-single mutant mice lack harmaline tremor entirely and have approximately 100% broader Purkinje cell action potentials compared to wild-type or Kv3.1-single mutants.\",\n      \"method\": \"Kv3.3 and Kv3.1 single and double mutant mice, harmaline pharmacology, Purkinje cell electrophysiology, immunohistochemistry\",\n      \"journal\": \"The European journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — KO with defined pharmacological challenge, electrophysiology, and behavioral phenotype\",\n      \"pmids\": [\"15217387\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Dendritic Kv3.3 channels in Purkinje cells oppose Ca2+ spike initiation and regulate propagation of electrical activity and Ca2+ influx in distal dendrites; Kv3.3 knockout mice show enhanced dendritic excitability and specifically elevated Ca2+ signals in distal dendrites following climbing fiber activation.\",\n      \"method\": \"Kv3.3 knockout mice, voltage clamp, local pharmacology, Ca2+ imaging throughout Purkinje cell dendritic tree\",\n      \"journal\": \"Journal of neurophysiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — KO with multiple orthogonal methods (pharmacology, voltage clamp, Ca2+ imaging)\",\n      \"pmids\": [\"20357073\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"KCNC3 R423H mutation exhibits dominant-negative properties similar to R420H (nonfunctional subunit suppressing current amplitude); however, R423H additionally produces altered gating when co-assembled with wild-type subunits (hyperpolarized activation shift, slower activation, modestly slower deactivation), while R420H-containing channels retain near-wild-type gating, explaining why R423H causes early-onset disease.\",\n      \"method\": \"Xenopus oocyte heterologous expression, electrophysiology of heteromeric channels with varying wild-type/mutant subunit ratios\",\n      \"journal\": \"Human mutation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — electrophysiology with heteromeric channel analysis distinguishing dual dominant-negative and gain-of-function gating effects\",\n      \"pmids\": [\"19953606\", \"22289912\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"A C-terminal domain of Kv3.3 directs channels to distal dendrites; the targeting domain includes a consensus sequence predicted to bind PDZ-type protein-protein interaction motifs, as demonstrated by retargeting experiments using in vivo viral injections in the electrosensory system.\",\n      \"method\": \"Immunohistochemistry, in vivo viral injection for recombinant channel expression, C-terminal domain deletion and retargeting experiments\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct retargeting experiment in vivo, single lab\",\n      \"pmids\": [\"16354911\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"KCNC3 R420H protein displays reduced complex glycan adducts compared to wild-type, is retained in the Golgi rather than trafficking to the plasma membrane (24% of wild-type surface expression by biotinylation), and causes altered Golgi and cellular morphology.\",\n      \"method\": \"Surface biotinylation, immunohistochemistry, electron microscopy, biochemical analysis of glycosylation\",\n      \"journal\": \"Neurobiology of disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (biotinylation, EM, glycan analysis), single lab\",\n      \"pmids\": [\"25152487\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"KCNC3 R423H mutation results in altered glycosylation and aberrant retention in anterograde/endosomal vesicles, loss of plasma membrane expression, and aberrant intracellular retention of EGFR in mammalian cells; in Drosophila, co-expression of KCNC3 R423H with dEGFR rescues the eye phenotype, implicating indirect effects on EGFR signaling.\",\n      \"method\": \"Mammalian cell expression with immunofluorescence and electrophysiology, Drosophila genetic co-expression rescue experiments\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple methods (cell biology, Drosophila genetics) in single study\",\n      \"pmids\": [\"28467418\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Expression of mutant Kv3.3 R424H (equivalent to human R423H) in cultured cerebellar Purkinje cells via lentiviral vector decreases outward current density, broadens action potentials, elevates basal [Ca2+]i, impairs dendrite development, and causes cell death selectively in Purkinje cells; all rescued by blocking P/Q-type Ca2+ channels.\",\n      \"method\": \"Lentiviral expression in mouse cerebellar cultures, patch-clamp electrophysiology, Ca2+ imaging, pharmacological rescue\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — defined cellular phenotype with pharmacological rescue, single lab\",\n      \"pmids\": [\"24218544\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"C-terminal proline deletion (p.Pro583_Pro585del) in KCNC3 causes normal membrane trafficking but slower channel inactivation and decreased sensitivity to actin depolymerizer latrunculin B, linking the C-terminal proline-rich domain to inactivation kinetics and actin-dependent channel regulation.\",\n      \"method\": \"Mammalian cell expression, electrophysiology, latrunculin B pharmacology, immunofluorescence\",\n      \"journal\": \"Cerebellum\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — electrophysiology with pharmacological probe in cell expression system, single lab\",\n      \"pmids\": [\"29949095\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Deletion of Kv3.3 (but not Kv3.1) at the calyx of Held presynaptic terminal reduces presynaptic Kv3 channel immunolabelling, increases presynaptic AP duration, facilitates neurotransmitter release, and enhances short-term depression during high-frequency transmission; modeling showed increased vesicle release probability and accelerated activity-dependent vesicle replenishment in the Kv3.3 KO.\",\n      \"method\": \"Kv3.3 KO mice, electrophysiology, immunolabelling, computational modeling of synaptic transmission\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO with defined presynaptic electrophysiological phenotype, in vivo auditory recordings, and computational modeling\",\n      \"pmids\": [\"35510987\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"In auditory brainstem, LSO neurons absolutely require Kv3.3 subunits for fast AP repolarization (half-width doubled in Kv3.3 KO) and to sustain high-frequency firing, while MNTB neurons can utilize either Kv3.1 or Kv3.3 subunits interchangeably; loss of Kv3.3 in LSO increases Ca2+ influx and AP failure rates.\",\n      \"method\": \"Kv3.3 and Kv3.1 knockout mice, patch-clamp electrophysiology, Ca2+ imaging, TEA pharmacology, western blot\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — subunit-specific KO with multiple orthogonal measurements distinguishing cell-type-specific roles\",\n      \"pmids\": [\"32246836\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Antisense oligonucleotides (ASOs) directed against Kcnc3 suppress Kv3.3 mRNA and protein in the cerebellum; in mice bearing the G592R SCA13 mutation, this reverses TBK1 overactivation, restores Hax-1 levels, reduces Cd63 (late endosome marker), and rescues rotarod motor performance, without affecting wild-type mice.\",\n      \"method\": \"Intracerebroventricular ASO infusion in wild-type and G592R knock-in mice, western blot, behavioral rotarod testing\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo ASO treatment with biochemical and behavioral endpoints, single lab\",\n      \"pmids\": [\"34820911\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"In zebrafish, an infant-onset SCA13 mutation dramatically increases Purkinje cell excitability, stunts dendritic growth, impairs synaptogenesis, and causes rapid cell death during cerebellar development; reducing excitability increases early Purkinje cell survival. An adult-onset mutation reduces excitability during evoked high-frequency spiking without altering basal tonic firing, and does not cause developmental degeneration.\",\n      \"method\": \"Zebrafish in vivo electrophysiology, live imaging of Purkinje cell development, genetic loss-of-function with defined cellular phenotypes\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo zebrafish model with electrophysiology and imaging, single lab\",\n      \"pmids\": [\"32644043\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1992,\n      \"finding\": \"KCNC3 (Kv3.3) is encoded by at least two exons separated by ~3 kb of intervening sequence; the N-terminal 212 amino acids are encoded by a single exon and the hydrophobic core (from S1 transmembrane segment onward) by a separate exon. The gene was mapped to human chromosome 19.\",\n      \"method\": \"Genomic cloning, cDNA isolation, Southern blotting, chromosomal mapping\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct genomic and molecular characterization\",\n      \"pmids\": [\"1740329\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"A missense mutation G434V in Kcnc3 (in the voltage sensor transmembrane domain) causes complete loss of voltage-gated conductance in electrophysiological recordings, broadening of action potentials, and decreased neuronal firing, resulting in spatial learning deficits in mice.\",\n      \"method\": \"CRISPR knock-in mouse, in vitro electrophysiology of mutant channel, behavioral fear conditioning and spatial learning assays\",\n      \"journal\": \"PNAS\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — CRISPR KI with channel electrophysiology and behavioral phenotype, single lab\",\n      \"pmids\": [\"35881790\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"A Kozak sequence variant (c.-6C>A) upstream of KCNC3 increases protein expression by enhanced translation initiation without affecting transcription rate, as demonstrated by luciferase assays, qPCR, and methylation analysis.\",\n      \"method\": \"Luciferase reporter assay, qPCR, methylation analysis in cell transfection system\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple functional assays in single study\",\n      \"pmids\": [\"39596509\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"The Kv3.3 E675K variant causes reduced current amplitude and more pronounced cumulative inactivation in Xenopus oocytes; both wild-type and E675K Kv3.3 inactivation is antagonized by increased extracellular potassium, suggesting a mechanism for potential therapeutic intervention.\",\n      \"method\": \"Voltage-clamp recordings in Xenopus oocytes, pharmacological manipulation of extracellular K+\",\n      \"journal\": \"Frontiers in cellular neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 — electrophysiology in heterologous expression system, single lab\",\n      \"pmids\": [\"39416683\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"KCNC3/Kv3.3 is a voltage-gated Shaw-family K+ channel that rapidly activates at depolarized potentials and mediates fast action potential repolarization in fast-spiking neurons (especially cerebellar Purkinje cells and auditory brainstem neurons); its cytoplasmic C-terminus recruits Arp2/3 via Hax-1 to form a cortical actin network that prevents rapid N-type inactivation, while the N-terminus mediates PKC-regulated N-type inactivation (phosphorylation of Ser3/Ser9), Ankyrin-R links Kv3.3 to the β3 spectrin cytoskeleton at the Purkinje cell soma membrane, and Kv3.3 directly binds and stimulates TBK1 to regulate Hax-1 trafficking and neuronal survival—with disease-causing SCA13 mutations acting via dominant-negative current suppression (R420H, R423H), altered gating with negative activation shifts (F448L, R423H in heteromers), or disruption of the actin/TBK1/Hax-1 pathway (G592R, proline deletions), ultimately impairing high-frequency firing in cerebellar and auditory circuits.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"KCNC3 encodes the voltage-gated potassium channel Kv3.3, a Shaw-family subunit that activates at depolarized potentials to mediate fast action potential repolarization in high-frequency-firing neurons, including cerebellar Purkinje cells, deep cerebellar nuclei neurons, and auditory brainstem neurons [PMID:18256249, PMID:32246836, PMID:35510987]. The channel undergoes N-type inactivation via its N-terminal domain, regulated by PKC phosphorylation of Ser3 and Ser9, while the cytoplasmic C-terminus recruits Hax-1 and Arp2/3 to assemble a cortical actin network that prevents rapid inactivation during brief depolarizations [PMID:12923191, PMID:18539595, PMID:26997484]. Kv3.3 also directly binds and stimulates TBK1 to control Hax-1 trafficking via multivesicular bodies, and is anchored at the Purkinje cell soma membrane through Ankyrin-R/β3-spectrin linkage [PMID:33741962, PMID:34785580]. Dominant mutations in KCNC3 cause spinocerebellar ataxia type 13 (SCA13) through mechanisms including dominant-negative current suppression (R420H, R423H), shifted voltage dependence of activation (F448L, R423H), and disruption of the C-terminal actin/TBK1 signaling axis (G592R), leading to impaired high-frequency firing, elevated intracellular calcium, and Purkinje cell degeneration [PMID:16501573, PMID:19953606, PMID:24218544, PMID:32644043].\",\n  \"teleology\": [\n    {\n      \"year\": 1992,\n      \"claim\": \"The genomic organization and chromosomal location of KCNC3 were established, revealing a split-exon architecture encoding the N-terminal and transmembrane domains separately on chromosome 19, providing the molecular foundation for subsequent functional studies.\",\n      \"evidence\": \"Genomic cloning, cDNA isolation, Southern blotting, and chromosomal mapping\",\n      \"pmids\": [\"1740329\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No functional characterization of channel activity at this stage\", \"Splice variant diversity not explored\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"The N-terminal domain was identified as the mediator of N-type inactivation, resolving how Kv3.3 can transition between sustained and inactivating modes; concurrently, Kv3.1/Kv3.3 double-knockout mice revealed that these subunits jointly control parallel fiber AP width and presynaptic calcium dynamics in the cerebellum.\",\n      \"evidence\": \"Start-codon and Kozak mutagenesis with electrophysiology in CHO/HEK cells; single and double KO mice with synaptic recordings\",\n      \"pmids\": [\"12923191\", \"12930807\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular identity of inactivation ball peptide not resolved\", \"Relative contribution of Kv3.3 vs Kv3.1 at individual synapses unclear\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Kv3.3, not Kv3.1, was shown to be the essential subunit for Purkinje cell AP repolarization and olivocerebellar tremor generation, establishing subunit-specific non-redundant roles in the cerebellar circuit.\",\n      \"evidence\": \"Kv3.3 and Kv3.1 single and double KO mice with harmaline tremor assay and Purkinje cell electrophysiology\",\n      \"pmids\": [\"15217387\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of subunit-specific expression patterns in Purkinje cells unknown\", \"Whether Kv3.3 homo- or heteromeric channels predominate in vivo unresolved\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"A C-terminal targeting domain containing a putative PDZ-binding motif was identified as directing Kv3.3 to distal dendrites, revealing that subcellular localization is encoded within the channel itself.\",\n      \"evidence\": \"In vivo viral expression with C-terminal deletion/retargeting in electrosensory lateral line lobe\",\n      \"pmids\": [\"16354911\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Identity of the interacting PDZ-domain protein not determined\", \"Relevance to mammalian dendritic targeting not confirmed\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"The first SCA13-causing mutations were functionally characterized, showing that R420H acts as a dominant-negative non-conducting subunit while F448L shifts activation negatively, establishing two distinct pathogenic mechanisms for the same disease locus.\",\n      \"evidence\": \"Xenopus oocyte expression with electrophysiology and co-expression of wild-type/mutant subunits\",\n      \"pmids\": [\"16501573\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo consequences of these mutations on Purkinje cell firing not yet tested\", \"Whether heteromeric gating changes contribute to R420H pathogenesis unknown\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"PKC was shown to regulate N-type inactivation through phosphorylation of Ser3/Ser9, providing a signaling mechanism by which neuromodulators dynamically switch Kv3.3 between inactivating and sustained modes; simultaneously, Kv3.3 was proven essential for complex spike spikelet generation and motor coordination specifically within Purkinje cells via cell-type-specific rescue.\",\n      \"evidence\": \"Mutagenesis of Ser3/Ser9 with PKC pharmacology; Purkinje-cell-restricted transgenic rescue in Kcnc3 KO mice with electrophysiology and behavioral testing\",\n      \"pmids\": [\"18539595\", \"18256249\", \"18448641\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological conditions triggering PKC-mediated modulation in vivo unknown\", \"Why motor learning was not rescued by Purkinje cell Kv3.3 restoration remains unexplained\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Genetic epistasis between Kv3.3 in Purkinje cells and Kv3.1 in deep cerebellar nuclei demonstrated that fast repolarization at multiple nodes of the cerebellar circuit is required for normal motor coordination, establishing a circuit-level requirement beyond single cell types.\",\n      \"evidence\": \"Multi-allele Kcnc1/Kcnc3 crosses with Purkinje-cell transgenic rescue, DCN electrophysiology, and gait analysis\",\n      \"pmids\": [\"20016089\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific Kv3 subunit composition in DCN neurons not defined\", \"Contribution of mossy fiber inputs and other interneurons not addressed\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Dendritic Kv3.3 channels were shown to oppose Ca²⁺ spike initiation in distal Purkinje cell dendrites, extending the functional role of Kv3.3 beyond somatic/axonal repolarization to include regulation of dendritic excitability and climbing fiber-evoked calcium signaling.\",\n      \"evidence\": \"Kv3.3 KO mice with voltage clamp, local pharmacology, and dendritic Ca²⁺ imaging\",\n      \"pmids\": [\"20357073\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis for dendritic vs somatic Kv3.3 targeting not resolved\", \"Functional impact on synaptic plasticity at climbing fiber synapses not tested\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"R423H was distinguished from R420H by its dual mechanism: both dominant-negative suppression and altered heteromeric channel gating (hyperpolarized activation, slowed kinetics), explaining the more severe early-onset SCA13 phenotype with R423H.\",\n      \"evidence\": \"Xenopus oocyte electrophysiology with defined wild-type/mutant subunit ratios\",\n      \"pmids\": [\"19953606\", \"22289912\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis for why adjacent arginine mutations produce different gating effects unknown\", \"In vivo confirmation of heteromeric gating shifts lacking\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Mutant Kv3.3 (R424H) was shown to cause Purkinje cell death via calcium overload secondary to AP broadening, with rescue by P/Q-type calcium channel blockade, establishing a mechanistic link from channel dysfunction to neurodegeneration.\",\n      \"evidence\": \"Lentiviral expression of R424H in cultured Purkinje cells with electrophysiology, Ca²⁺ imaging, and pharmacological rescue\",\n      \"pmids\": [\"24218544\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether P/Q-type blockade rescues degeneration in vivo untested\", \"Contribution of non-cell-autonomous mechanisms not evaluated\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"The C-terminal proline-rich domain was identified as an Arp2/3/Hax-1 recruitment platform that builds a cortical actin network preventing N-type inactivation during brief depolarizations, revealing a non-canonical channel function in cytoskeletal organization.\",\n      \"evidence\": \"Co-IP, pulldown, in vitro actin assays, electrophysiology, and stem cell-derived neuron imaging; disease mutation disrupts Arp2/3 but not Hax-1 binding\",\n      \"pmids\": [\"26997484\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural details of the proline-rich domain interaction with Hax-1 and Arp2/3 not resolved\", \"Whether actin-dependent regulation operates in all Kv3.3-expressing neuron types unknown\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"A proline deletion (p.Pro583_Pro585del) in the C-terminal domain slowed inactivation and reduced actin-dependent regulation without impairing surface trafficking, providing finer dissection of how the proline-rich region controls gating through the actin cytoskeleton.\",\n      \"evidence\": \"Mammalian cell electrophysiology with latrunculin B pharmacology and immunofluorescence\",\n      \"pmids\": [\"29949095\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether this variant is pathogenic in humans not established\", \"Direct biophysical mechanism linking actin to inactivation gate not resolved\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Cell-type-specific knockout studies in auditory brainstem demonstrated that LSO neurons absolutely require Kv3.3 for fast repolarization while MNTB neurons can substitute Kv3.1, establishing differential subunit dependence across auditory nuclei.\",\n      \"evidence\": \"Kv3.3 and Kv3.1 KO mice with patch-clamp, Ca²⁺ imaging, and TEA pharmacology in LSO and MNTB\",\n      \"pmids\": [\"32246836\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Hearing phenotype in Kv3.3 KO mice not fully characterized\", \"Whether Kv3.3 heteromerizes with Kv3.1 in these nuclei not determined\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Kv3.3 was discovered to directly bind and activate TBK1, controlling Hax-1 trafficking through multivesicular bodies; the G592R SCA13 mutation hyperactivates TBK1, causing Hax-1 degradation, exosome release, and neuronal death—a non-conducting function distinct from ion permeation. ASO-mediated suppression of mutant Kv3.3 reversed TBK1 overactivation and rescued motor function in G592R mice.\",\n      \"evidence\": \"Reciprocal Co-IP, subcellular fractionation, cell death assays, mouse models; intracerebroventricular ASO with biochemical and rotarod endpoints\",\n      \"pmids\": [\"33741962\", \"34820911\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of Kv3.3-TBK1 interaction not determined\", \"Whether TBK1 activation contributes to other SCA13 mutations unknown\", \"Long-term therapeutic window of ASO approach not defined\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Ankyrin-R was identified as the cytoskeletal anchor linking Kv3.3 to β3 spectrin at the Purkinje cell soma; loss of AnkR reduced somatic Kv3.3 levels and caused ataxia and neurodegeneration, establishing a somatic retention mechanism complementary to the C-terminal dendritic targeting signal.\",\n      \"evidence\": \"Co-IP, conditional AnkR KO (Nestin-Cre and Pcp2-Cre), immunofluorescence, behavioral phenotyping\",\n      \"pmids\": [\"34785580\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Binding interface between AnkR and Kv3.3 not mapped\", \"Whether AnkR also anchors Kv3.3 outside the cerebellum unknown\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Kv3.3 was shown to be the dominant presynaptic Kv3 subunit at the calyx of Held, where it constrains AP duration, limits neurotransmitter release, and supports faithful high-frequency transmission; a voltage-sensor mutation (G434V) separately confirmed that loss of Kv3.3 conductance impairs spatial learning.\",\n      \"evidence\": \"Kv3.3 KO mice with calyx electrophysiology and computational modeling; CRISPR G434V KI mice with behavioral testing\",\n      \"pmids\": [\"35510987\", \"35881790\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Kv3.3 loss at the calyx affects auditory processing in behaving animals not tested\", \"Cognitive circuits dependent on Kv3.3 beyond cerebellum and auditory brainstem not mapped\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Translational regulation of Kv3.3 was demonstrated via a Kozak sequence variant that increases protein expression, and the E675K C-terminal variant was shown to reduce current and enhance cumulative inactivation that is antagonized by elevated extracellular potassium.\",\n      \"evidence\": \"Luciferase reporter/qPCR assays for Kozak variant; Xenopus oocyte voltage-clamp for E675K with extracellular K⁺ manipulation\",\n      \"pmids\": [\"39596509\", \"39416683\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo relevance of Kozak variant to disease phenotype unresolved\", \"Mechanism by which extracellular K⁺ antagonizes inactivation not clarified at structural level\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the high-resolution structure of the Kv3.3 C-terminal signaling complex (Hax-1/Arp2/3/TBK1), the identity of PDZ-domain proteins mediating dendritic targeting, whether non-conducting functions of Kv3.3 contribute to pathogenesis across all SCA13 mutations, and the full extent of Kv3.3-dependent circuits beyond the cerebellum and auditory brainstem.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No high-resolution structure of Kv3.3 or its signaling complexes\", \"PDZ-domain targeting partner unidentified\", \"Relative contribution of conducting vs non-conducting functions to SCA13 pathogenesis not quantified\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005215\", \"supporting_discovery_ids\": [0, 1, 2, 6, 18, 19]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [3, 4]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [3, 5]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 3, 5, 14, 18]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [3, 4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [6, 7, 8, 9, 10, 11, 18, 19]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [2, 4]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [0, 12, 16, 21]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"HAX1\",\n      \"TBK1\",\n      \"ANK1\",\n      \"SPTBN2\",\n      \"ACTR2\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}