{"gene":"KCNAB2","run_date":"2026-06-10T01:55:23","timeline":{"discoveries":[{"year":2002,"finding":"Kvβ2 (KCNAB2) binds to Kv1 and Kv4 family α subunits and is a member of the aldo-ketoreductase (AKR) superfamily. In Kvβ2-null mice, Kv1.1 and Kv1.2 localize normally in cerebellar basket cell terminals and juxtaparanodal regions of myelinated nerves, and normal glycosylation patterns are observed, indicating that loss of Kvβ2 chaperone-like activity does not account for the null phenotype (reduced lifespan, occasional seizures, cold swim-induced tremors). Mice carrying the Y90F point mutation abolishing AKR-like catalytic activity show no overt phenotype, ruling out typical AKR catalytic activity as the functionally critical mechanism.","method":"Gene targeting in embryonic stem cells (null and Y90F knock-in mice); immunolocalization of Kv1.1/Kv1.2 in brain; glycosylation analysis of brain lysates","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — two independent genetic models (null and point-mutant knock-in) with multiple orthogonal readouts (localization, glycosylation, behavior), rigorously ruling out competing mechanistic hypotheses","pmids":["11825900"],"is_preprint":false},{"year":2011,"finding":"Deletion of Kcnab2 in mice causes deficits in associative learning and memory. In projection neurons of the lateral nucleus of the amygdala, loss of Kvβ2 reduces the slow afterhyperpolarization following a burst of action potentials and increases neuronal excitability, as measured by whole-cell current-clamp recording.","method":"Constitutive Kcnab2 knockout mice; behavioral assays (associative memory); whole-cell current-clamp electrophysiology in amygdala lateral nucleus neurons","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean KO with defined cellular phenotype (reduced sAHP, increased excitability) plus behavioral phenotype, multiple orthogonal methods in single study","pmids":["21209188"],"is_preprint":false},{"year":2022,"finding":"Cell-type-specific CRISPR/Cas9 mutagenesis of Kcnab2 in adult mouse dopamine neurons reduces surface expression of Kv1.2 (the primary Kv1 pore-forming subunit in dopamine neurons) and shifts the voltage dependence of potassium channel inactivation toward more hyperpolarized potentials. This broadens the action potential waveform, reduces afterhyperpolarization amplitude, and increases spike timing irregularity and excitability in spontaneously firing dopamine neurons recorded in slice.","method":"Viral-mediated cell-type-specific CRISPR/Cas9 mutagenesis in dopamine neurons; surface expression assay for Kv1.2; whole-cell patch-clamp electrophysiology in brain slices","journal":"Journal of neurophysiology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — conditional CRISPR KO with multiple electrophysiological readouts and surface trafficking measurement, all in the same study","pmids":["35788155"],"is_preprint":false},{"year":2020,"finding":"Modulation of Kcnab2 expression in rat GH3 mammosomatotroph cells produces proportionate changes in GH mRNA and secreted GH peptide: partial knockdown reduces GH expression and secretion, while overexpression increases them, indicating that KCNAB2 expression level positively regulates growth hormone secretion in pituitary somatotroph cells.","method":"Plasmid transfection (overexpression) and shRNA knockdown of Kcnab2 in GH3 cells; qPCR for GH mRNA; ELISA for secreted GH","journal":"Journal of neurosurgery","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — gain- and loss-of-function in a cell line with two orthogonal readouts (mRNA and protein secretion), single lab, no mechanistic pathway resolved","pmids":["32109873"],"is_preprint":false},{"year":2023,"finding":"Overexpression of KCNAB2 in human NSCLC cells inhibits AKT-mTOR signaling, suppresses cell growth, proliferation, motility, and promotes apoptosis; CRISPR/Cas9-induced KCNAB2 knockout augments AKT-mTOR activation and malignant behaviors. In vivo, KCNAB2-overexpressing A549 xenograft growth is significantly inhibited.","method":"Exogenous overexpression and CRISPR/Cas9 knockout in NSCLC cell lines; protein chip analysis; Western blotting for AKT-mTOR pathway; xenograft mouse model","journal":"Cell death discovery","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — bidirectional manipulation (OE + KO) with in vitro and in vivo readouts and pathway identification, single lab","pmids":["37852974"],"is_preprint":false},{"year":2025,"finding":"FTO-mediated m6A methylation of KCNAB2 mRNA negatively regulates KCNAB2 expression in NSCLC cells; FTO knockdown increases KCNAB2 expression. KCNAB2 overexpression inhibits NSCLC cell proliferation, migration, invasion, and M2 macrophage polarization by inactivating the PI3K/AKT pathway.","method":"m6A RNA immunoprecipitation assay; FTO knockdown; KCNAB2 overexpression; Western blotting for PI3K/AKT; cell-based functional assays; rescue experiments; xenograft mouse model","journal":"Journal of biochemical and molecular toxicology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — m6A RIP plus rescue experiments and bidirectional manipulation, single lab, multiple orthogonal functional assays","pmids":["40114527"],"is_preprint":false},{"year":1996,"finding":"The human KCNAB2 (KCNA2B) gene was localized to chromosome 1p36.3 by somatic cell hybrid mapping and fluorescence in situ hybridization (FISH).","method":"Somatic cell hybrid mapping; fluorescence in situ hybridization (FISH)","journal":"Genomics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — two orthogonal chromosomal mapping methods in a single focused study","pmids":["8838324"],"is_preprint":false}],"current_model":"KCNAB2 encodes the potassium channel auxiliary subunit Kvβ2, an aldo-ketoreductase superfamily member that forms complexes with Kv1 (and Kv4) α subunits; it promotes surface trafficking of Kv1.2 and modulates channel gating (voltage dependence of inactivation and afterhyperpolarization), thereby regulating neuronal excitability in multiple cell types (cerebellar, amygdala projection neurons, dopamine neurons); its AKR catalytic activity and classical chaperone function are dispensable for in vivo phenotypes, yet it positively regulates GH secretion in pituitary somatotrophs and suppresses tumor cell growth and PI3K/AKT signaling in NSCLC, with its expression in turn regulated by FTO-mediated m6A methylation."},"narrative":{"mechanistic_narrative":"KCNAB2 encodes Kvβ2, an auxiliary subunit of voltage-gated potassium channels that binds Kv1 and Kv4 family α subunits and belongs to the aldo-ketoreductase superfamily, functioning to regulate neuronal excitability across multiple cell types [PMID:11825900, PMID:21209188, PMID:35788155]. In dopamine neurons, Kvβ2 promotes surface expression of the Kv1.2 pore-forming subunit and sets the voltage dependence of channel inactivation; its loss shifts inactivation toward hyperpolarized potentials, broadens the action potential, reduces afterhyperpolarization, and increases firing irregularity and excitability [PMID:35788155]. A parallel role in amygdala projection neurons, where Kvβ2 loss reduces the slow afterhyperpolarization and raises excitability, underlies deficits in associative learning and memory in knockout mice [PMID:21209188]. Genetic dissection establishes that the chaperone-like and classical aldo-ketoreductase catalytic activities of Kvβ2 are dispensable for its in vivo function: channel α subunits localize and glycosylate normally without Kvβ2, and a catalytically dead Y90F knock-in shows no overt phenotype [PMID:11825900]. Beyond the nervous system, KCNAB2 expression level positively regulates growth hormone secretion in pituitary somatotroph cells [PMID:32109873], and in non-small-cell lung cancer KCNAB2 acts as a tumor suppressor that inhibits PI3K/AKT-mTOR signaling, proliferation, migration, and M2 macrophage polarization while promoting apoptosis [PMID:37852974, PMID:40114527]; its expression in this context is negatively controlled by FTO-mediated m6A methylation of KCNAB2 mRNA [PMID:40114527].","teleology":[{"year":1996,"claim":"Before functional characterization, the genomic location of human KCNAB2 was unknown; mapping it provided the anchor for subsequent disease and expression studies.","evidence":"Somatic cell hybrid mapping and FISH localizing KCNAB2 to chromosome 1p36.3","pmids":["8838324"],"confidence":"Medium","gaps":["No functional or mechanistic information established","No link to a specific disease locus demonstrated"]},{"year":2002,"claim":"It was unknown which biochemical property of Kvβ2 — its α-subunit binding, chaperone-like trafficking role, or aldo-ketoreductase catalysis — accounts for its physiological importance; genetic dissection ruled out chaperone and catalytic functions as the critical mechanism.","evidence":"Kcnab2-null and Y90F catalytic-dead knock-in mice with α-subunit immunolocalization, glycosylation analysis, and behavioral phenotyping","pmids":["11825900"],"confidence":"High","gaps":["Did not identify the mechanism that actually drives the null phenotype","Cellular electrophysiological consequence not resolved in this study"]},{"year":2011,"claim":"How Kvβ2 loss translates into a systems-level phenotype was unclear; linking it to reduced slow afterhyperpolarization and increased excitability in amygdala neurons connected the subunit to associative memory.","evidence":"Constitutive Kcnab2 knockout mice with associative-memory behavioral assays and whole-cell current-clamp recording in lateral amygdala neurons","pmids":["21209188"],"confidence":"High","gaps":["Specific channel α subunit mediating the sAHP change not identified","Constitutive KO cannot exclude developmental compensation"]},{"year":2022,"claim":"Whether Kvβ2 acts cell-autonomously in the adult to control trafficking and gating was unresolved; conditional CRISPR in adult dopamine neurons showed it sets Kv1.2 surface expression and inactivation voltage dependence to shape firing.","evidence":"Viral cell-type-specific CRISPR/Cas9 mutagenesis in dopamine neurons with Kv1.2 surface-expression assay and slice patch-clamp","pmids":["35788155"],"confidence":"High","gaps":["Molecular basis of the inactivation voltage shift not resolved","Behavioral consequence of dopamine-neuron-specific loss not tested"]},{"year":2020,"claim":"A role outside neurons was unknown; modulating Kcnab2 in somatotroph cells showed its expression level positively regulates growth hormone synthesis and secretion.","evidence":"Overexpression and shRNA knockdown of Kcnab2 in GH3 cells with GH qPCR and secreted-GH ELISA","pmids":["32109873"],"confidence":"Medium","gaps":["No mechanistic pathway linking KCNAB2 to GH expression resolved","Single cell line, single lab"]},{"year":2023,"claim":"Whether KCNAB2 has a role in cancer was untested; bidirectional manipulation in NSCLC defined it as a tumor suppressor acting through AKT-mTOR signaling.","evidence":"Overexpression and CRISPR knockout in NSCLC cell lines, protein chip, Western blot for AKT-mTOR, and A549 xenografts","pmids":["37852974"],"confidence":"Medium","gaps":["Direct molecular link between KCNAB2 and AKT-mTOR not defined","Whether the effect depends on channel-associated function unknown"]},{"year":2025,"claim":"How KCNAB2 expression is controlled in cancer and how it shapes the tumor microenvironment were open; FTO-mediated m6A methylation was shown to repress KCNAB2, whose restoration inhibits malignancy and M2 macrophage polarization via PI3K/AKT.","evidence":"m6A RIP, FTO knockdown, KCNAB2 overexpression with rescue experiments, PI3K/AKT Western blot, functional assays, and xenografts","pmids":["40114527"],"confidence":"Medium","gaps":["Reader/effector linking m6A mark to KCNAB2 transcript fate not identified","Mechanism connecting KCNAB2 to macrophage polarization not resolved"]},{"year":null,"claim":"The molecular mechanism by which Kvβ2 governs Kv1 channel gating and trafficking in vivo — given that its chaperone and aldo-ketoreductase activities are dispensable — and how the same subunit suppresses PI3K/AKT signaling in non-neuronal cells remain unexplained.","evidence":"","pmids":[],"confidence":"High","gaps":["The functionally critical biochemical activity of Kvβ2 in vivo is unidentified","No structural model linking subunit binding to the inactivation voltage shift","Connection between channel-subunit role and tumor-suppressor PI3K/AKT signaling unresolved"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,2]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[2]}],"pathway":[{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[1,2]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[4,5]}],"complexes":["Kv1 (Kv1.2) voltage-gated potassium channel complex"],"partners":["KCNA2","KCNA1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q13303","full_name":"Voltage-gated potassium channel subunit beta-2","aliases":["K(+) channel subunit beta-2","Kv-beta-2","hKvbeta2"],"length_aa":367,"mass_kda":41.0,"function":"Regulatory subunit of the voltage-gated potassium (Kv) Shaker channels composed of pore-forming and potassium-conducting alpha subunits and of regulatory beta subunits (PubMed:11825900, PubMed:7649300). The beta-2/KCNAB2 cytoplasmic subunit promotes potassium channel closure via a mechanism that does not involve physical obstruction of the channel pore (PubMed:11825900, PubMed:7649300). Promotes the inactivation of Kv1.4/KCNA4 and Kv1.5/KCNA5 alpha subunit-containing channels (PubMed:11825900, PubMed:7649300). Displays nicotinamide adenine dinucleotide phosphate (NADPH)-dependent aldoketoreductase activity by catalyzing the NADPH-dependent reduction of a wide range of aldehyde and ketone substrates (By similarity). Substrate specificity includes methylglyoxal, 9,10-phenanthrenequinone, prostaglandin J2, 4-nitrobenzaldehyde, 4-nitroacetophenone and 4-oxo-trans-2-nonenal (in vitro, no physiological substrate identified yet) (By similarity). The binding of oxidized and reduced nucleotide alters Kv channel gating and may contribute to dynamic fine tuning of cell excitability (By similarity). Contributes to the regulation of nerve signaling, and prevents neuronal hyperexcitability (By similarity)","subcellular_location":"Cytoplasm; Membrane; Cell membrane; Cell projection, axon; Synapse, synaptosome; Cytoplasm, cytoskeleton","url":"https://www.uniprot.org/uniprotkb/Q13303/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/KCNAB2","classification":"Not Classified","n_dependent_lines":7,"n_total_lines":1208,"dependency_fraction":0.005794701986754967},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/KCNAB2","total_profiled":1310},"omim":[{"mim_id":"612240","title":"ATRIAL FIBRILLATION, FAMILIAL, 7; ATFB7","url":"https://www.omim.org/entry/612240"},{"mim_id":"607872","title":"CHROMOSOME 1p36 DELETION SYNDROME, DISTAL","url":"https://www.omim.org/entry/607872"},{"mim_id":"601142","title":"POTASSIUM CHANNEL, VOLTAGE-GATED, SHAKER-RELATED SUBFAMILY, BETA MEMBER 2; KCNAB2","url":"https://www.omim.org/entry/601142"},{"mim_id":"601141","title":"POTASSIUM CHANNEL, VOLTAGE-GATED, SHAKER-RELATED SUBFAMILY, BETA MEMBER 1; KCNAB1","url":"https://www.omim.org/entry/601141"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"brain","ntpm":202.4}],"url":"https://www.proteinatlas.org/search/KCNAB2"},"hgnc":{"alias_symbol":["AKR6A5","KCNA2B","HKvbeta2.1","HKvbeta2.2"],"prev_symbol":[]},"alphafold":{"accession":"Q13303","domains":[{"cath_id":"3.20.20.100","chopping":"38-248_311-326","consensus_level":"high","plddt":98.4143,"start":38,"end":326}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q13303","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q13303-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q13303-F1-predicted_aligned_error_v6.png","plddt_mean":91.25},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=KCNAB2","jax_strain_url":"https://www.jax.org/strain/search?query=KCNAB2"},"sequence":{"accession":"Q13303","fasta_url":"https://rest.uniprot.org/uniprotkb/Q13303.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q13303/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q13303"}},"corpus_meta":[{"pmid":"11580756","id":"PMC_11580756","title":"Loss of the potassium channel beta-subunit gene, KCNAB2, is associated with epilepsy in patients with 1p36 deletion syndrome.","date":"2001","source":"Epilepsia","url":"https://pubmed.ncbi.nlm.nih.gov/11580756","citation_count":75,"is_preprint":false},{"pmid":"11825900","id":"PMC_11825900","title":"Genetic analysis of the mammalian K+ channel beta subunit Kvbeta 2 (Kcnab2).","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11825900","citation_count":62,"is_preprint":false},{"pmid":"21209188","id":"PMC_21209188","title":"Deletion of the mouse homolog of KCNAB2, a gene linked to monosomy 1p36, results in associative memory impairments and amygdala hyperexcitability.","date":"2011","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/21209188","citation_count":45,"is_preprint":false},{"pmid":"8838324","id":"PMC_8838324","title":"Localization of two potassium channel beta subunit genes, KCNA1B and KCNA2B.","date":"1996","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/8838324","citation_count":21,"is_preprint":false},{"pmid":"32109873","id":"PMC_32109873","title":"Role of KCNAB2 expression in modulating hormone secretion in somatotroph pituitary adenoma.","date":"2020","source":"Journal of neurosurgery","url":"https://pubmed.ncbi.nlm.nih.gov/32109873","citation_count":15,"is_preprint":false},{"pmid":"35788155","id":"PMC_35788155","title":"The potassium channel auxiliary subunit Kvβ2 (Kcnab2) regulates Kv1 channels and dopamine neuron firing.","date":"2022","source":"Journal of neurophysiology","url":"https://pubmed.ncbi.nlm.nih.gov/35788155","citation_count":12,"is_preprint":false},{"pmid":"40114527","id":"PMC_40114527","title":"FTO-mediated m6A Methylation of KCNAB2 Inhibits Tumor Property of Non-Small Cell Lung Cancer Cells and M2 Macrophage Polarization by Inactivating the PI3K/AKT Pathway.","date":"2025","source":"Journal of biochemical and molecular toxicology","url":"https://pubmed.ncbi.nlm.nih.gov/40114527","citation_count":6,"is_preprint":false},{"pmid":"37852974","id":"PMC_37852974","title":"KCNAB2 overexpression inhibits human non-small-cell lung cancer cell growth in vitro and in vivo.","date":"2023","source":"Cell death discovery","url":"https://pubmed.ncbi.nlm.nih.gov/37852974","citation_count":4,"is_preprint":false},{"pmid":"10983719","id":"PMC_10983719","title":"The murine Bis1 seizure gene and the Kcnab2 gene encoding the beta2-subunit of the K+ channel are different.","date":"2000","source":"Neurogenetics","url":"https://pubmed.ncbi.nlm.nih.gov/10983719","citation_count":2,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.02.26.640405","title":"Distinct forms of amyloid-β moderate sleep duration through NAD  <sup>+</sup>  -linked redox metabolism in Alzheimer’s disease","date":"2025-03-03","source":"bioRxiv","url":"https://doi.org/10.1101/2025.02.26.640405","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7432,"output_tokens":2108,"usd":0.026958,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9083,"output_tokens":2809,"usd":0.05782,"stage2_stop_reason":"end_turn"},"total_usd":0.084778,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2002,\n      \"finding\": \"Kvβ2 (KCNAB2) binds to Kv1 and Kv4 family α subunits and is a member of the aldo-ketoreductase (AKR) superfamily. In Kvβ2-null mice, Kv1.1 and Kv1.2 localize normally in cerebellar basket cell terminals and juxtaparanodal regions of myelinated nerves, and normal glycosylation patterns are observed, indicating that loss of Kvβ2 chaperone-like activity does not account for the null phenotype (reduced lifespan, occasional seizures, cold swim-induced tremors). Mice carrying the Y90F point mutation abolishing AKR-like catalytic activity show no overt phenotype, ruling out typical AKR catalytic activity as the functionally critical mechanism.\",\n      \"method\": \"Gene targeting in embryonic stem cells (null and Y90F knock-in mice); immunolocalization of Kv1.1/Kv1.2 in brain; glycosylation analysis of brain lysates\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — two independent genetic models (null and point-mutant knock-in) with multiple orthogonal readouts (localization, glycosylation, behavior), rigorously ruling out competing mechanistic hypotheses\",\n      \"pmids\": [\"11825900\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Deletion of Kcnab2 in mice causes deficits in associative learning and memory. In projection neurons of the lateral nucleus of the amygdala, loss of Kvβ2 reduces the slow afterhyperpolarization following a burst of action potentials and increases neuronal excitability, as measured by whole-cell current-clamp recording.\",\n      \"method\": \"Constitutive Kcnab2 knockout mice; behavioral assays (associative memory); whole-cell current-clamp electrophysiology in amygdala lateral nucleus neurons\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with defined cellular phenotype (reduced sAHP, increased excitability) plus behavioral phenotype, multiple orthogonal methods in single study\",\n      \"pmids\": [\"21209188\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Cell-type-specific CRISPR/Cas9 mutagenesis of Kcnab2 in adult mouse dopamine neurons reduces surface expression of Kv1.2 (the primary Kv1 pore-forming subunit in dopamine neurons) and shifts the voltage dependence of potassium channel inactivation toward more hyperpolarized potentials. This broadens the action potential waveform, reduces afterhyperpolarization amplitude, and increases spike timing irregularity and excitability in spontaneously firing dopamine neurons recorded in slice.\",\n      \"method\": \"Viral-mediated cell-type-specific CRISPR/Cas9 mutagenesis in dopamine neurons; surface expression assay for Kv1.2; whole-cell patch-clamp electrophysiology in brain slices\",\n      \"journal\": \"Journal of neurophysiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — conditional CRISPR KO with multiple electrophysiological readouts and surface trafficking measurement, all in the same study\",\n      \"pmids\": [\"35788155\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Modulation of Kcnab2 expression in rat GH3 mammosomatotroph cells produces proportionate changes in GH mRNA and secreted GH peptide: partial knockdown reduces GH expression and secretion, while overexpression increases them, indicating that KCNAB2 expression level positively regulates growth hormone secretion in pituitary somatotroph cells.\",\n      \"method\": \"Plasmid transfection (overexpression) and shRNA knockdown of Kcnab2 in GH3 cells; qPCR for GH mRNA; ELISA for secreted GH\",\n      \"journal\": \"Journal of neurosurgery\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — gain- and loss-of-function in a cell line with two orthogonal readouts (mRNA and protein secretion), single lab, no mechanistic pathway resolved\",\n      \"pmids\": [\"32109873\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Overexpression of KCNAB2 in human NSCLC cells inhibits AKT-mTOR signaling, suppresses cell growth, proliferation, motility, and promotes apoptosis; CRISPR/Cas9-induced KCNAB2 knockout augments AKT-mTOR activation and malignant behaviors. In vivo, KCNAB2-overexpressing A549 xenograft growth is significantly inhibited.\",\n      \"method\": \"Exogenous overexpression and CRISPR/Cas9 knockout in NSCLC cell lines; protein chip analysis; Western blotting for AKT-mTOR pathway; xenograft mouse model\",\n      \"journal\": \"Cell death discovery\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — bidirectional manipulation (OE + KO) with in vitro and in vivo readouts and pathway identification, single lab\",\n      \"pmids\": [\"37852974\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"FTO-mediated m6A methylation of KCNAB2 mRNA negatively regulates KCNAB2 expression in NSCLC cells; FTO knockdown increases KCNAB2 expression. KCNAB2 overexpression inhibits NSCLC cell proliferation, migration, invasion, and M2 macrophage polarization by inactivating the PI3K/AKT pathway.\",\n      \"method\": \"m6A RNA immunoprecipitation assay; FTO knockdown; KCNAB2 overexpression; Western blotting for PI3K/AKT; cell-based functional assays; rescue experiments; xenograft mouse model\",\n      \"journal\": \"Journal of biochemical and molecular toxicology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — m6A RIP plus rescue experiments and bidirectional manipulation, single lab, multiple orthogonal functional assays\",\n      \"pmids\": [\"40114527\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"The human KCNAB2 (KCNA2B) gene was localized to chromosome 1p36.3 by somatic cell hybrid mapping and fluorescence in situ hybridization (FISH).\",\n      \"method\": \"Somatic cell hybrid mapping; fluorescence in situ hybridization (FISH)\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — two orthogonal chromosomal mapping methods in a single focused study\",\n      \"pmids\": [\"8838324\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"KCNAB2 encodes the potassium channel auxiliary subunit Kvβ2, an aldo-ketoreductase superfamily member that forms complexes with Kv1 (and Kv4) α subunits; it promotes surface trafficking of Kv1.2 and modulates channel gating (voltage dependence of inactivation and afterhyperpolarization), thereby regulating neuronal excitability in multiple cell types (cerebellar, amygdala projection neurons, dopamine neurons); its AKR catalytic activity and classical chaperone function are dispensable for in vivo phenotypes, yet it positively regulates GH secretion in pituitary somatotrophs and suppresses tumor cell growth and PI3K/AKT signaling in NSCLC, with its expression in turn regulated by FTO-mediated m6A methylation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"KCNAB2 encodes Kvβ2, an auxiliary subunit of voltage-gated potassium channels that binds Kv1 and Kv4 family α subunits and belongs to the aldo-ketoreductase superfamily, functioning to regulate neuronal excitability across multiple cell types [#0, #1, #2]. In dopamine neurons, Kvβ2 promotes surface expression of the Kv1.2 pore-forming subunit and sets the voltage dependence of channel inactivation; its loss shifts inactivation toward hyperpolarized potentials, broadens the action potential, reduces afterhyperpolarization, and increases firing irregularity and excitability [#2]. A parallel role in amygdala projection neurons, where Kvβ2 loss reduces the slow afterhyperpolarization and raises excitability, underlies deficits in associative learning and memory in knockout mice [#1]. Genetic dissection establishes that the chaperone-like and classical aldo-ketoreductase catalytic activities of Kvβ2 are dispensable for its in vivo function: channel α subunits localize and glycosylate normally without Kvβ2, and a catalytically dead Y90F knock-in shows no overt phenotype [#0]. Beyond the nervous system, KCNAB2 expression level positively regulates growth hormone secretion in pituitary somatotroph cells [#3], and in non-small-cell lung cancer KCNAB2 acts as a tumor suppressor that inhibits PI3K/AKT-mTOR signaling, proliferation, migration, and M2 macrophage polarization while promoting apoptosis [#4, #5]; its expression in this context is negatively controlled by FTO-mediated m6A methylation of KCNAB2 mRNA [#5].\",\n  \"teleology\": [\n    {\n      \"year\": 1996,\n      \"claim\": \"Before functional characterization, the genomic location of human KCNAB2 was unknown; mapping it provided the anchor for subsequent disease and expression studies.\",\n      \"evidence\": \"Somatic cell hybrid mapping and FISH localizing KCNAB2 to chromosome 1p36.3\",\n      \"pmids\": [\"8838324\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No functional or mechanistic information established\", \"No link to a specific disease locus demonstrated\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"It was unknown which biochemical property of Kvβ2 — its α-subunit binding, chaperone-like trafficking role, or aldo-ketoreductase catalysis — accounts for its physiological importance; genetic dissection ruled out chaperone and catalytic functions as the critical mechanism.\",\n      \"evidence\": \"Kcnab2-null and Y90F catalytic-dead knock-in mice with α-subunit immunolocalization, glycosylation analysis, and behavioral phenotyping\",\n      \"pmids\": [\"11825900\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not identify the mechanism that actually drives the null phenotype\", \"Cellular electrophysiological consequence not resolved in this study\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"How Kvβ2 loss translates into a systems-level phenotype was unclear; linking it to reduced slow afterhyperpolarization and increased excitability in amygdala neurons connected the subunit to associative memory.\",\n      \"evidence\": \"Constitutive Kcnab2 knockout mice with associative-memory behavioral assays and whole-cell current-clamp recording in lateral amygdala neurons\",\n      \"pmids\": [\"21209188\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific channel α subunit mediating the sAHP change not identified\", \"Constitutive KO cannot exclude developmental compensation\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Whether Kvβ2 acts cell-autonomously in the adult to control trafficking and gating was unresolved; conditional CRISPR in adult dopamine neurons showed it sets Kv1.2 surface expression and inactivation voltage dependence to shape firing.\",\n      \"evidence\": \"Viral cell-type-specific CRISPR/Cas9 mutagenesis in dopamine neurons with Kv1.2 surface-expression assay and slice patch-clamp\",\n      \"pmids\": [\"35788155\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of the inactivation voltage shift not resolved\", \"Behavioral consequence of dopamine-neuron-specific loss not tested\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"A role outside neurons was unknown; modulating Kcnab2 in somatotroph cells showed its expression level positively regulates growth hormone synthesis and secretion.\",\n      \"evidence\": \"Overexpression and shRNA knockdown of Kcnab2 in GH3 cells with GH qPCR and secreted-GH ELISA\",\n      \"pmids\": [\"32109873\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No mechanistic pathway linking KCNAB2 to GH expression resolved\", \"Single cell line, single lab\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Whether KCNAB2 has a role in cancer was untested; bidirectional manipulation in NSCLC defined it as a tumor suppressor acting through AKT-mTOR signaling.\",\n      \"evidence\": \"Overexpression and CRISPR knockout in NSCLC cell lines, protein chip, Western blot for AKT-mTOR, and A549 xenografts\",\n      \"pmids\": [\"37852974\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct molecular link between KCNAB2 and AKT-mTOR not defined\", \"Whether the effect depends on channel-associated function unknown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"How KCNAB2 expression is controlled in cancer and how it shapes the tumor microenvironment were open; FTO-mediated m6A methylation was shown to repress KCNAB2, whose restoration inhibits malignancy and M2 macrophage polarization via PI3K/AKT.\",\n      \"evidence\": \"m6A RIP, FTO knockdown, KCNAB2 overexpression with rescue experiments, PI3K/AKT Western blot, functional assays, and xenografts\",\n      \"pmids\": [\"40114527\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Reader/effector linking m6A mark to KCNAB2 transcript fate not identified\", \"Mechanism connecting KCNAB2 to macrophage polarization not resolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The molecular mechanism by which Kvβ2 governs Kv1 channel gating and trafficking in vivo — given that its chaperone and aldo-ketoreductase activities are dispensable — and how the same subunit suppresses PI3K/AKT signaling in non-neuronal cells remain unexplained.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"The functionally critical biochemical activity of Kvβ2 in vivo is unidentified\", \"No structural model linking subunit binding to the inactivation voltage shift\", \"Connection between channel-subunit role and tumor-suppressor PI3K/AKT signaling unresolved\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [1, 2]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [4, 5]}\n    ],\n    \"complexes\": [\"Kv1 (Kv1.2) voltage-gated potassium channel complex\"],\n    \"partners\": [\"KCNA2\", \"KCNA1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}