{"gene":"KCNJ14","run_date":"2026-06-10T02:59:49","timeline":{"discoveries":[{"year":1998,"finding":"Kir2.4 (IRK4) was cloned from rat brain and shown to form low-conductance inwardly rectifying K+ channels (15 pS) when heterologously expressed in Xenopus oocytes and mammalian cells, with markedly lower affinity for Ba2+ (Ki = 390 µM) and Cs+ (Ki = 8.06 mM) blockers compared to other Kir2 family members. Ba2+-mediated block of Kir2.4 in hypoglossal motoneurons (HMs) in brainstem slices evoked tonic activity and increased spike discharge frequency, establishing a direct role in controlling motoneuron excitability.","method":"Heterologous expression in Xenopus oocytes and mammalian cells, patch-clamp electrophysiology, in situ hybridization, brainstem slice recordings with pharmacological block","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — functional reconstitution in two heterologous expression systems plus direct in situ pharmacological dissection in native tissue, multiple orthogonal methods in a single focused study","pmids":["9592090"],"is_preprint":false},{"year":2000,"finding":"Human Kir2.4 cDNA was cloned from a retinal library and mapped to chromosome 19q13.1–q13.3. Expression in Xenopus oocytes generated strong inwardly rectifying K+ currents that were enhanced by extracellular alkalinization, demonstrating pH sensitivity as a functional property of the channel.","method":"cDNA cloning, Xenopus oocyte expression, two-electrode voltage clamp, Northern analysis, in situ hybridization, somatic cell hybridization mapping","journal":"American journal of physiology. Cell physiology","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — functional reconstitution in oocytes with electrophysiological characterization plus genomic mapping, single lab but multiple orthogonal methods","pmids":["10942728"],"is_preprint":false},{"year":2000,"finding":"Kir2.4 lacks the C-terminal PDZ-domain recognition motif (X-S/T-X-V/I) present in Kir2.1 and Kir2.3, and its C-terminus did not interact with PDZ domains 1–3 of PSD-95/SAP90 in yeast two-hybrid assays, establishing that Kir2.4 does not couple to PSD-95 family scaffolding proteins.","method":"Yeast two-hybrid assay, sequence analysis of C-terminal motifs","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — yeast two-hybrid with sequence validation; negative result for Kir2.4 PDZ binding is well-supported by direct experiment but is a single lab, single method","pmids":["10627592"],"is_preprint":false},{"year":2002,"finding":"Kir2.4 co-assembles physically with Kir2.1 to form functional heteromeric channels. Co-expression of dominant-negative Kir2.1 or Kir2.4 subunits suppressed currents from wild-type partners in Xenopus oocytes; His6-Kir2.1/FLAG-Kir2.4 co-precipitation confirmed physical association in COS-7 cells. Kir2.1–Kir2.4 tandem and co-injected channels showed Ba2+ sensitivity greater than either subunit alone.","method":"Dominant-negative co-expression in Xenopus oocytes, pulldown/co-immunoprecipitation with epitope-tagged subunits in COS-7 cells, tandem-linked construct expression, two-electrode voltage clamp","journal":"The Journal of physiology","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — physical co-assembly confirmed by pulldown plus functional consequence demonstrated with dominant-negative suppression and tandem construct; multiple orthogonal methods in a single study","pmids":["12381809"],"is_preprint":false},{"year":2004,"finding":"Kir2.4 has intermediate cholesterol sensitivity compared to other Kir2 family members (Kir2.1/2.2 most sensitive, Kir2.3 least sensitive, Kir2.4 intermediate), and like other Kir2.x channels, Kir2.4 partitions virtually exclusively into Triton-insoluble, cholesterol-rich lipid raft membrane fractions.","method":"Whole-cell patch clamp in null cell line after cholesterol manipulation, Triton X-100 membrane fractionation, Western blot","journal":"Biophysical journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct fractionation experiment for lipid raft targeting and electrophysiological comparison of cholesterol sensitivity across family members; Kir2.4 is one of four subunits compared, single lab","pmids":["15465867"],"is_preprint":false},{"year":2005,"finding":"Kir2.4 accumulates within the Golgi complex rather than at the plasma membrane when expressed alone. A 20-amino-acid stretch in the Kir2.1 C-terminus containing a tyrosine-dependent YXXPhi adaptin-binding motif is necessary and sufficient to promote anterograde Golgi-to-plasma-membrane transport. This signal is dominant in Kir2.1/Kir2.4 heteromers, controlling the stoichiometry of heteromeric channels at the cell surface.","method":"Chimeric channel constructs between Kir2.1 and Kir2.4, fluorescence microscopy of subcellular localization in mammalian cells, site-directed mutagenesis of sorting motif","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — chimera mapping plus mutagenesis identified necessary and sufficient sequence for Golgi export, functional localization consequence demonstrated; multiple orthogonal approaches in a single study","pmids":["15827083"],"is_preprint":false},{"year":2007,"finding":"Andersen syndrome mutations in the slide helix of Kir2.1 (Y68D, D78Y) exert dominant-negative effects on Kir2.4 channels (as well as Kir2.2 and Kir2.3), demonstrating that slide helix–C-terminus interaction required for gating is conserved across Kir2 heteromers including Kir2.4.","method":"Voltage clamp in Xenopus oocytes and patch clamp in HEK293 cells, chemiluminescence surface-expression assay, PIP2 lipid binding assay, yeast two-hybrid","journal":"Cardiovascular research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — dominant-negative effect on Kir2.4 confirmed electrophysiologically; Kir2.4 is one of three tested partners and mechanistic detail (slide helix–C-terminus interaction) was defined primarily for Kir2.1, single lab","pmids":["17568571"],"is_preprint":false},{"year":2007,"finding":"Kir2.4 is expressed in human pulmonary artery smooth muscle (HPASM) cells and contributes substantially to the native inward rectifier K+ current. The whole-cell K+ current in HPASM cells showed Ba2+ block characteristics (IC50 ~39 µM at -100 mV) and voltage-independence more similar to cloned Kir2.4 (IC50 ~66 µM) than Kir2.1 (IC50 ~4 µM), and single-channel conductance (~21 pS) matched both Kir2.1 and Kir2.4.","method":"Patch-clamp electrophysiology (whole-cell and single-channel), RT-PCR, pharmacological comparison with cloned Kir2.1 and Kir2.4 expressed in HEK cells","journal":"The Journal of membrane biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct electrophysiological comparison of native current properties to cloned channels; RT-PCR for expression; single lab, indirect inference of Kir2.4 contribution","pmids":["17347781"],"is_preprint":false},{"year":2008,"finding":"In ON bipolar cells of mouse retina, Kir2.4 channel protein is concentrated specifically in the dendritic tips, a subcellular localization determined using a transgenic Grm6-GFP mouse line that selectively labels ON bipolar cells.","method":"Transgenic mouse model (Grm6-GFP) for cell-type-specific isolation, sorted-cell cDNA library, immunolocalization in retinal sections","journal":"The Journal of comparative neurology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct immunolocalization in a genetically defined cell type with subcellular resolution; single lab, localization without functional consequence tested","pmids":["18671302"],"is_preprint":false},{"year":2013,"finding":"Kir2.4 interacts physically with Gαo1 (especially the GDP-bound/inactive form), and this interaction modulates Kir2.4 surface expression and basal current. GDP-bound and inactive-mutant Gαo reduce Kir2.4 current and surface expression, whereas constitutively active Gαo has little effect. Gβγ increases Kir2.4 current and surface expression; m-phosducin (which sequesters Gβγ) reduces both. In ON bipolar cells lacking Gβ3, Kir2.4 localization at dendritic tips is reduced.","method":"Yeast two-hybrid screen (initial identification), co-immunoprecipitation in HEK293 cells and retinal tissue, two-electrode voltage clamp in Xenopus oocytes with G-protein subunit co-injection, plasma membrane imaging of cerulean-tagged Kir2.4 in oocytes, immunofluorescence in Gβ3 knockout mouse retina","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — physical interaction confirmed by co-IP plus yeast two-hybrid; functional modulation of current and surface expression tested with multiple G-protein subunit combinations; in vivo validation in knockout mouse; multiple orthogonal methods","pmids":["23339194"],"is_preprint":false},{"year":2015,"finding":"Functional electrophysiological characterization of zebrafish drKir2.4 expressed in HEK cells revealed that it produces inwardly rectifying K+ currents with intermediate rectification strength and high Ba2+ sensitivity (IC50 = 1.8 µM), markedly different from mammalian Kir2.4 (Ki ~390 µM), highlighting species-specific structural differences.","method":"Heterologous expression in HEK cells, patch-clamp electrophysiology, Ba2+ dose-response analysis","journal":"Pflugers Archiv : European journal of physiology","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — direct functional reconstitution of zebrafish Kir2.4 in HEK cells with electrophysiological characterization; single lab, zebrafish ortholog","pmids":["25991088"],"is_preprint":false},{"year":2022,"finding":"KCNJ14 knockdown in colorectal cancer cell lines (HCT116 and SW480) significantly reduced cell proliferation and migration (assessed by MTT, colony-forming, wound healing, and transwell assays) and decreased levels of mTOR signaling pathway-related proteins as detected by Western blot.","method":"siRNA-mediated knockdown, MTT assay, colony-forming assay, wound healing assay, transwell migration assay, Western blot for mTOR pathway proteins","journal":"BMC medical genomics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function with defined proliferation/migration phenotype and biochemical readout of mTOR pathway; single lab, no rescue experiment, no direct channel activity measurement","pmids":["36100894"],"is_preprint":false}],"current_model":"KCNJ14 (Kir2.4/IRK4) encodes a strongly inwardly rectifying K+ channel that forms low-conductance (15 pS) homomeric channels with low Ba2+/Cs+ sensitivity, preferentially expressed in cranial motoneurons and retinal neurons, where it controls neuronal excitability; it co-assembles with Kir2.1 to form functional heteromeric channels with intermediate Ba2+ sensitivity; its surface expression is regulated by a Golgi export signal in Kir2.1 (dominant in heteromers) and by Gβγ (promoting membrane targeting) antagonized by GDP-bound Gαo; in retinal ON bipolar cells Gβγ-dependent trafficking concentrates Kir2.4 at dendritic tips; the channel is pH-sensitive (activated by alkalinization) and partitions into lipid rafts with intermediate cholesterol sensitivity; in cancer cells, KCNJ14 knockdown suppresses proliferation, migration, and mTOR signaling."},"narrative":{"mechanistic_narrative":"KCNJ14 encodes Kir2.4 (IRK4), a strongly inwardly rectifying K+ channel that controls neuronal excitability, demonstrated directly in hypoglossal motoneurons where Ba2+ block of the channel evokes tonic firing and increased spike frequency [PMID:9592090]. Cloned from rat brain and human retina, the channel forms low-conductance (~15 pS) homomeric channels distinguished from other Kir2 members by markedly low affinity for Ba2+ and Cs+ blockers, and its currents are enhanced by extracellular alkalinization [PMID:9592090, PMID:10942728]. Kir2.4 physically co-assembles with Kir2.1 to form functional heteromeric channels with intermediate Ba2+ sensitivity, confirmed by reciprocal dominant-negative suppression, co-precipitation of epitope-tagged subunits, and tandem constructs [PMID:12381809]; the conserved slide-helix–C-terminus gating interaction is shared across these heteromers, such that Andersen syndrome Kir2.1 mutations exert dominant-negative effects on Kir2.4 [PMID:17568571]. Surface delivery is governed at the secretory pathway: expressed alone, Kir2.4 accumulates in the Golgi, and a tyrosine-dependent YXXΦ adaptin-binding Golgi-export signal in the Kir2.1 C-terminus is dominant in heteromers, setting the stoichiometry of channels reaching the membrane [PMID:15827083]. Trafficking is further tuned by heterotrimeric G proteins: Kir2.4 binds Gαo1 (preferentially the GDP-bound form, which suppresses surface expression and current) while Gβγ promotes membrane targeting, and loss of Gβ3 reduces Kir2.4 concentration at the dendritic tips of retinal ON bipolar cells where the channel is normally enriched [PMID:18671302, PMID:23339194]. Unlike Kir2.1 and Kir2.3, Kir2.4 lacks a C-terminal PDZ-binding motif and does not couple to PSD-95 scaffolds [PMID:10627592], but like other family members it partitions into cholesterol-rich lipid rafts with intermediate cholesterol sensitivity [PMID:15465867]. In colorectal cancer cell lines, KCNJ14 knockdown reduces proliferation and migration and lowers mTOR pathway protein levels [PMID:36100894].","teleology":[{"year":1998,"claim":"Established the molecular identity and signature pharmacology of Kir2.4 and tied it directly to control of motoneuron firing, answering whether this channel sets neuronal excitability.","evidence":"Cloning from rat brain, heterologous expression in oocytes and mammalian cells, patch clamp, and Ba2+ block in brainstem slice motoneurons","pmids":["9592090"],"confidence":"High","gaps":["Native channel composition (homomer vs heteromer) in motoneurons not resolved","No structural basis for low Ba2+/Cs+ affinity"]},{"year":2000,"claim":"Defined the human gene, its chromosomal locus, and pH sensitivity, establishing alkalinization-dependent activation as an intrinsic functional property.","evidence":"cDNA cloning from retinal library, oocyte two-electrode voltage clamp, Northern/in situ, somatic cell hybrid mapping","pmids":["10942728"],"confidence":"High","gaps":["Molecular determinant of pH sensing not mapped","Physiological context of pH modulation untested"]},{"year":2000,"claim":"Showed Kir2.4 diverges from its paralogs by lacking a PDZ-binding motif, answering whether it uses PSD-95-family scaffolds for synaptic anchoring.","evidence":"Yeast two-hybrid against PSD-95/SAP90 PDZ domains and C-terminal motif sequence analysis","pmids":["10627592"],"confidence":"Medium","gaps":["Negative result from a single method/lab","Alternative anchoring partners not identified"]},{"year":2002,"claim":"Demonstrated that Kir2.4 is not obligately homomeric but co-assembles with Kir2.1 into heteromers with distinct Ba2+ sensitivity, redefining the native channel population.","evidence":"Dominant-negative co-expression, His6/FLAG co-precipitation in COS-7, tandem constructs, voltage clamp","pmids":["12381809"],"confidence":"High","gaps":["Stoichiometry of native heteromers not quantified","Whether other Kir2 subunits also co-assemble untested here"]},{"year":2004,"claim":"Placed Kir2.4 within cholesterol-rich lipid raft microdomains and ranked its cholesterol sensitivity among Kir2 family members, addressing membrane microenvironment dependence.","evidence":"Triton X-100 fractionation, Western blot, and whole-cell patch clamp after cholesterol manipulation","pmids":["15465867"],"confidence":"Medium","gaps":["Raft residency tested for one subunit among four compared","Functional consequence of raft partitioning for Kir2.4 specifically not isolated"]},{"year":2005,"claim":"Identified the secretory-pathway logic of heteromeric surface delivery, showing a dominant Kir2.1 Golgi-export signal overrides Kir2.4's Golgi retention.","evidence":"Kir2.1/Kir2.4 chimeras, subcellular fluorescence imaging, and site-directed mutagenesis of the YXXΦ motif","pmids":["15827083"],"confidence":"High","gaps":["Trafficking machinery (adaptin identity) acting on Kir2.4 not directly shown","Whether Kir2.4 homomers ever reach the surface in native cells unresolved"]},{"year":2007,"claim":"Showed the gating-critical slide-helix–C-terminus interaction is conserved in Kir2.4-containing heteromers, explaining how Kir2.1 disease mutations propagate dominant-negative effects.","evidence":"Voltage/patch clamp in oocytes and HEK293, chemiluminescence surface assay, PIP2 binding, yeast two-hybrid","pmids":["17568571"],"confidence":"Medium","gaps":["Mechanism defined primarily for Kir2.1; Kir2.4 one of three partners","No disease link to KCNJ14 itself established"]},{"year":2007,"claim":"Attributed a component of native inward rectifier current in pulmonary artery smooth muscle to Kir2.4 based on pharmacological fingerprint.","evidence":"Whole-cell/single-channel patch clamp, RT-PCR, and Ba2+ block comparison with cloned channels","pmids":["17347781"],"confidence":"Medium","gaps":["Contribution inferred from pharmacology, not genetic ablation","Heteromeric composition in HPASM not defined"]},{"year":2008,"claim":"Resolved a precise subcellular site for Kir2.4 in retinal ON bipolar cell dendritic tips, defining where the channel acts in the visual circuit.","evidence":"Grm6-GFP transgenic labeling, sorted-cell cDNA, and immunolocalization in retinal sections","pmids":["18671302"],"confidence":"Medium","gaps":["Functional role at dendritic tips not directly tested","Mechanism of tip targeting not yet addressed in this study"]},{"year":2013,"claim":"Established G-protein control of Kir2.4 trafficking, with Gβγ promoting and GDP-bound Gαo suppressing surface expression, and linked this to dendritic-tip enrichment in vivo.","evidence":"Yeast two-hybrid, co-IP in HEK293 and retina, oocyte voltage clamp with G-protein co-injection, membrane imaging, and Gβ3 knockout mouse retina immunofluorescence","pmids":["23339194"],"confidence":"High","gaps":["Upstream receptor driving Gαo/Gβγ regulation not identified","Direct binding interface on Kir2.4 not mapped"]},{"year":2015,"claim":"Revealed strong species divergence in Kir2.4 pharmacology, with zebrafish ortholog showing high Ba2+ sensitivity unlike the mammalian channel.","evidence":"HEK expression, patch clamp, and Ba2+ dose-response of zebrafish drKir2.4","pmids":["25991088"],"confidence":"Medium","gaps":["Structural residues responsible for the affinity shift not identified","Mammalian inference limited by ortholog use"]},{"year":2022,"claim":"Implicated KCNJ14 in cancer cell behavior, linking its knockdown to reduced proliferation/migration and lowered mTOR signaling.","evidence":"siRNA knockdown in HCT116/SW480, MTT, colony-forming, wound healing, transwell assays, and mTOR-pathway Western blot","pmids":["36100894"],"confidence":"Medium","gaps":["No rescue experiment to confirm specificity","No demonstration that channel activity (vs non-conducting role) drives the phenotype","Mechanistic link between K+ flux and mTOR not established"]},{"year":null,"claim":"How channel conductance versus trafficking/scaffolding roles of Kir2.4 are coupled to downstream signaling such as mTOR, and the identity of the upstream G-protein-coupled receptor regulating its surface expression, remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No receptor upstream of Gαo/Gβγ regulation identified","Causal link between K+ conduction and mTOR signaling not established","No structural model of Kir2.4 homomer or Kir2.1/2.4 heteromer"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005215","term_label":"transporter activity","supporting_discovery_ids":[0,1,3]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[5,8,9]},{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[5]}],"pathway":[{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[0,8]},{"term_id":"R-HSA-382551","term_label":"Transport of small molecules","supporting_discovery_ids":[0,1]}],"complexes":["Kir2.1/Kir2.4 heteromeric inward rectifier channel"],"partners":["KCNJ2","GNAO1","GNB3"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q99712","full_name":"ATP-sensitive inward rectifier potassium channel 15","aliases":["Inward rectifier K(+) channel Kir1.3","Inward rectifier K(+) channel Kir4.2","Potassium channel, inwardly rectifying subfamily J member 15"],"length_aa":375,"mass_kda":42.6,"function":"Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. Their voltage dependence is regulated by the concentration of extracellular potassium; as external potassium is raised, the voltage range of the channel opening shifts to more positive voltages. The inward rectification is mainly due to the blockage of outward current by internal magnesium","subcellular_location":"Membrane; Cell membrane","url":"https://www.uniprot.org/uniprotkb/Q99712/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/KCNJ14","classification":"Not Classified","n_dependent_lines":8,"n_total_lines":1208,"dependency_fraction":0.006622516556291391},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/KCNJ14","total_profiled":1310},"omim":[{"mim_id":"605722","title":"POTASSIUM CHANNEL, INWARDLY RECTIFYING, SUBFAMILY J, MEMBER 16; KCNJ16","url":"https://www.omim.org/entry/605722"},{"mim_id":"603953","title":"POTASSIUM INWARDLY-RECTIFYING CHANNEL, SUBFAMILY J, MEMBER 14; KCNJ14","url":"https://www.omim.org/entry/603953"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"retina","ntpm":54.4}],"url":"https://www.proteinatlas.org/search/KCNJ14"},"hgnc":{"alias_symbol":["Kir2.4","IRK4"],"prev_symbol":[]},"alphafold":{"accession":"Q99712","domains":[{"cath_id":"2.60.40.1400","chopping":"12-37_173-355","consensus_level":"high","plddt":84.9474,"start":12,"end":355},{"cath_id":"1.10.287.70","chopping":"45-168","consensus_level":"high","plddt":91.811,"start":45,"end":168}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q99712","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q99712-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q99712-F1-predicted_aligned_error_v6.png","plddt_mean":85.31},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=KCNJ14","jax_strain_url":"https://www.jax.org/strain/search?query=KCNJ14"},"sequence":{"accession":"Q99712","fasta_url":"https://rest.uniprot.org/uniprotkb/Q99712.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q99712/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q99712"}},"corpus_meta":[{"pmid":"15465867","id":"PMC_15465867","title":"Cholesterol sensitivity and lipid raft targeting of Kir2.1 channels.","date":"2004","source":"Biophysical journal","url":"https://pubmed.ncbi.nlm.nih.gov/15465867","citation_count":155,"is_preprint":false},{"pmid":"11283229","id":"PMC_11283229","title":"Comparison of cloned Kir2 channels with native inward rectifier K+ channels from guinea-pig cardiomyocytes.","date":"2001","source":"The Journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/11283229","citation_count":126,"is_preprint":false},{"pmid":"10627592","id":"PMC_10627592","title":"Neuronal inwardly rectifying K(+) channels differentially couple to PDZ proteins of the PSD-95/SAP90 family.","date":"2000","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/10627592","citation_count":100,"is_preprint":false},{"pmid":"9592090","id":"PMC_9592090","title":"Kir2.4: a novel K+ inward rectifier channel associated with motoneurons of cranial nerve nuclei.","date":"1998","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/9592090","citation_count":94,"is_preprint":false},{"pmid":"23913861","id":"PMC_23913861","title":"The challenging environment on board the International Space Station affects endothelial cell function by triggering oxidative stress through thioredoxin interacting protein overexpression: the ESA-SPHINX experiment.","date":"2013","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/23913861","citation_count":86,"is_preprint":false},{"pmid":"19564397","id":"PMC_19564397","title":"Upregulation of inward rectifier K+ (Kir2) channels in dentate gyrus granule cells in temporal lobe epilepsy.","date":"2009","source":"The Journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/19564397","citation_count":77,"is_preprint":false},{"pmid":"17595223","id":"PMC_17595223","title":"Estrogen regulation of genes important for K+ channel signaling in the arcuate nucleus.","date":"2007","source":"Endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/17595223","citation_count":73,"is_preprint":false},{"pmid":"15827083","id":"PMC_15827083","title":"Selective Golgi export of Kir2.1 controls the stoichiometry of functional Kir2.x channel heteromers.","date":"2005","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/15827083","citation_count":67,"is_preprint":false},{"pmid":"15936845","id":"PMC_15936845","title":"Differential distribution of individual subunits of strongly inwardly rectifying potassium channels (Kir2 family) in rat brain.","date":"2005","source":"Brain research. 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Cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/24259419","citation_count":7,"is_preprint":false},{"pmid":"36100894","id":"PMC_36100894","title":"KCNJ14 knockdown significantly inhibited the proliferation and migration of colorectal cells.","date":"2022","source":"BMC medical genomics","url":"https://pubmed.ncbi.nlm.nih.gov/36100894","citation_count":4,"is_preprint":false},{"pmid":"34425102","id":"PMC_34425102","title":"Hypoxic and osmotic expression of Kir2.1 potassium channels in retinal pigment epithelial cells: Contribution to vascular endothelial growth factor expression.","date":"2021","source":"Experimental eye research","url":"https://pubmed.ncbi.nlm.nih.gov/34425102","citation_count":4,"is_preprint":false},{"pmid":"15771725","id":"PMC_15771725","title":"A refined radiation hybrid map of the telomeric region of bovine chromosome 18q25-q26 compared with human chromosome 19q13.","date":"2005","source":"Animal genetics","url":"https://pubmed.ncbi.nlm.nih.gov/15771725","citation_count":3,"is_preprint":false},{"pmid":"25063199","id":"PMC_25063199","title":"Molecular cloning of ion channels in Felis catus that are related to periodic paralyses in man: a contribution to the understanding of the genetic susceptibility to feline neck ventroflexion and paralysis.","date":"2014","source":"Biology open","url":"https://pubmed.ncbi.nlm.nih.gov/25063199","citation_count":2,"is_preprint":false},{"pmid":"41124752","id":"PMC_41124752","title":"High KCNJ14 expression is associated with an immunosuppressive tumor microenvironment and advanced pathological features: An RNA in situ hybridization-based analysis of colorectal carcinoma.","date":"2025","source":"Experimental and molecular pathology","url":"https://pubmed.ncbi.nlm.nih.gov/41124752","citation_count":0,"is_preprint":false},{"pmid":"42001417","id":"PMC_42001417","title":"Time-resolved single-cell transcriptomics maps zebrafish heart development.","date":"2026","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/42001417","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":26514,"output_tokens":3645,"usd":0.067109,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11337,"output_tokens":4044,"usd":0.078893,"stage2_stop_reason":"end_turn"},"total_usd":0.146002,"stage1_batch_id":"msgbatch_01BbTCMyrRPyhtEq6b1MdwCN","stage2_batch_id":"msgbatch_011dEed5bbxYvTAaQWKJevxu","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1998,\n      \"finding\": \"Kir2.4 (IRK4) was cloned from rat brain and shown to form low-conductance inwardly rectifying K+ channels (15 pS) when heterologously expressed in Xenopus oocytes and mammalian cells, with markedly lower affinity for Ba2+ (Ki = 390 µM) and Cs+ (Ki = 8.06 mM) blockers compared to other Kir2 family members. Ba2+-mediated block of Kir2.4 in hypoglossal motoneurons (HMs) in brainstem slices evoked tonic activity and increased spike discharge frequency, establishing a direct role in controlling motoneuron excitability.\",\n      \"method\": \"Heterologous expression in Xenopus oocytes and mammalian cells, patch-clamp electrophysiology, in situ hybridization, brainstem slice recordings with pharmacological block\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — functional reconstitution in two heterologous expression systems plus direct in situ pharmacological dissection in native tissue, multiple orthogonal methods in a single focused study\",\n      \"pmids\": [\"9592090\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Human Kir2.4 cDNA was cloned from a retinal library and mapped to chromosome 19q13.1–q13.3. Expression in Xenopus oocytes generated strong inwardly rectifying K+ currents that were enhanced by extracellular alkalinization, demonstrating pH sensitivity as a functional property of the channel.\",\n      \"method\": \"cDNA cloning, Xenopus oocyte expression, two-electrode voltage clamp, Northern analysis, in situ hybridization, somatic cell hybridization mapping\",\n      \"journal\": \"American journal of physiology. Cell physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — functional reconstitution in oocytes with electrophysiological characterization plus genomic mapping, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"10942728\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Kir2.4 lacks the C-terminal PDZ-domain recognition motif (X-S/T-X-V/I) present in Kir2.1 and Kir2.3, and its C-terminus did not interact with PDZ domains 1–3 of PSD-95/SAP90 in yeast two-hybrid assays, establishing that Kir2.4 does not couple to PSD-95 family scaffolding proteins.\",\n      \"method\": \"Yeast two-hybrid assay, sequence analysis of C-terminal motifs\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — yeast two-hybrid with sequence validation; negative result for Kir2.4 PDZ binding is well-supported by direct experiment but is a single lab, single method\",\n      \"pmids\": [\"10627592\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Kir2.4 co-assembles physically with Kir2.1 to form functional heteromeric channels. Co-expression of dominant-negative Kir2.1 or Kir2.4 subunits suppressed currents from wild-type partners in Xenopus oocytes; His6-Kir2.1/FLAG-Kir2.4 co-precipitation confirmed physical association in COS-7 cells. Kir2.1–Kir2.4 tandem and co-injected channels showed Ba2+ sensitivity greater than either subunit alone.\",\n      \"method\": \"Dominant-negative co-expression in Xenopus oocytes, pulldown/co-immunoprecipitation with epitope-tagged subunits in COS-7 cells, tandem-linked construct expression, two-electrode voltage clamp\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — physical co-assembly confirmed by pulldown plus functional consequence demonstrated with dominant-negative suppression and tandem construct; multiple orthogonal methods in a single study\",\n      \"pmids\": [\"12381809\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Kir2.4 has intermediate cholesterol sensitivity compared to other Kir2 family members (Kir2.1/2.2 most sensitive, Kir2.3 least sensitive, Kir2.4 intermediate), and like other Kir2.x channels, Kir2.4 partitions virtually exclusively into Triton-insoluble, cholesterol-rich lipid raft membrane fractions.\",\n      \"method\": \"Whole-cell patch clamp in null cell line after cholesterol manipulation, Triton X-100 membrane fractionation, Western blot\",\n      \"journal\": \"Biophysical journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct fractionation experiment for lipid raft targeting and electrophysiological comparison of cholesterol sensitivity across family members; Kir2.4 is one of four subunits compared, single lab\",\n      \"pmids\": [\"15465867\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Kir2.4 accumulates within the Golgi complex rather than at the plasma membrane when expressed alone. A 20-amino-acid stretch in the Kir2.1 C-terminus containing a tyrosine-dependent YXXPhi adaptin-binding motif is necessary and sufficient to promote anterograde Golgi-to-plasma-membrane transport. This signal is dominant in Kir2.1/Kir2.4 heteromers, controlling the stoichiometry of heteromeric channels at the cell surface.\",\n      \"method\": \"Chimeric channel constructs between Kir2.1 and Kir2.4, fluorescence microscopy of subcellular localization in mammalian cells, site-directed mutagenesis of sorting motif\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — chimera mapping plus mutagenesis identified necessary and sufficient sequence for Golgi export, functional localization consequence demonstrated; multiple orthogonal approaches in a single study\",\n      \"pmids\": [\"15827083\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Andersen syndrome mutations in the slide helix of Kir2.1 (Y68D, D78Y) exert dominant-negative effects on Kir2.4 channels (as well as Kir2.2 and Kir2.3), demonstrating that slide helix–C-terminus interaction required for gating is conserved across Kir2 heteromers including Kir2.4.\",\n      \"method\": \"Voltage clamp in Xenopus oocytes and patch clamp in HEK293 cells, chemiluminescence surface-expression assay, PIP2 lipid binding assay, yeast two-hybrid\",\n      \"journal\": \"Cardiovascular research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — dominant-negative effect on Kir2.4 confirmed electrophysiologically; Kir2.4 is one of three tested partners and mechanistic detail (slide helix–C-terminus interaction) was defined primarily for Kir2.1, single lab\",\n      \"pmids\": [\"17568571\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Kir2.4 is expressed in human pulmonary artery smooth muscle (HPASM) cells and contributes substantially to the native inward rectifier K+ current. The whole-cell K+ current in HPASM cells showed Ba2+ block characteristics (IC50 ~39 µM at -100 mV) and voltage-independence more similar to cloned Kir2.4 (IC50 ~66 µM) than Kir2.1 (IC50 ~4 µM), and single-channel conductance (~21 pS) matched both Kir2.1 and Kir2.4.\",\n      \"method\": \"Patch-clamp electrophysiology (whole-cell and single-channel), RT-PCR, pharmacological comparison with cloned Kir2.1 and Kir2.4 expressed in HEK cells\",\n      \"journal\": \"The Journal of membrane biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct electrophysiological comparison of native current properties to cloned channels; RT-PCR for expression; single lab, indirect inference of Kir2.4 contribution\",\n      \"pmids\": [\"17347781\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"In ON bipolar cells of mouse retina, Kir2.4 channel protein is concentrated specifically in the dendritic tips, a subcellular localization determined using a transgenic Grm6-GFP mouse line that selectively labels ON bipolar cells.\",\n      \"method\": \"Transgenic mouse model (Grm6-GFP) for cell-type-specific isolation, sorted-cell cDNA library, immunolocalization in retinal sections\",\n      \"journal\": \"The Journal of comparative neurology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct immunolocalization in a genetically defined cell type with subcellular resolution; single lab, localization without functional consequence tested\",\n      \"pmids\": [\"18671302\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Kir2.4 interacts physically with Gαo1 (especially the GDP-bound/inactive form), and this interaction modulates Kir2.4 surface expression and basal current. GDP-bound and inactive-mutant Gαo reduce Kir2.4 current and surface expression, whereas constitutively active Gαo has little effect. Gβγ increases Kir2.4 current and surface expression; m-phosducin (which sequesters Gβγ) reduces both. In ON bipolar cells lacking Gβ3, Kir2.4 localization at dendritic tips is reduced.\",\n      \"method\": \"Yeast two-hybrid screen (initial identification), co-immunoprecipitation in HEK293 cells and retinal tissue, two-electrode voltage clamp in Xenopus oocytes with G-protein subunit co-injection, plasma membrane imaging of cerulean-tagged Kir2.4 in oocytes, immunofluorescence in Gβ3 knockout mouse retina\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — physical interaction confirmed by co-IP plus yeast two-hybrid; functional modulation of current and surface expression tested with multiple G-protein subunit combinations; in vivo validation in knockout mouse; multiple orthogonal methods\",\n      \"pmids\": [\"23339194\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Functional electrophysiological characterization of zebrafish drKir2.4 expressed in HEK cells revealed that it produces inwardly rectifying K+ currents with intermediate rectification strength and high Ba2+ sensitivity (IC50 = 1.8 µM), markedly different from mammalian Kir2.4 (Ki ~390 µM), highlighting species-specific structural differences.\",\n      \"method\": \"Heterologous expression in HEK cells, patch-clamp electrophysiology, Ba2+ dose-response analysis\",\n      \"journal\": \"Pflugers Archiv : European journal of physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct functional reconstitution of zebrafish Kir2.4 in HEK cells with electrophysiological characterization; single lab, zebrafish ortholog\",\n      \"pmids\": [\"25991088\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"KCNJ14 knockdown in colorectal cancer cell lines (HCT116 and SW480) significantly reduced cell proliferation and migration (assessed by MTT, colony-forming, wound healing, and transwell assays) and decreased levels of mTOR signaling pathway-related proteins as detected by Western blot.\",\n      \"method\": \"siRNA-mediated knockdown, MTT assay, colony-forming assay, wound healing assay, transwell migration assay, Western blot for mTOR pathway proteins\",\n      \"journal\": \"BMC medical genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function with defined proliferation/migration phenotype and biochemical readout of mTOR pathway; single lab, no rescue experiment, no direct channel activity measurement\",\n      \"pmids\": [\"36100894\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"KCNJ14 (Kir2.4/IRK4) encodes a strongly inwardly rectifying K+ channel that forms low-conductance (15 pS) homomeric channels with low Ba2+/Cs+ sensitivity, preferentially expressed in cranial motoneurons and retinal neurons, where it controls neuronal excitability; it co-assembles with Kir2.1 to form functional heteromeric channels with intermediate Ba2+ sensitivity; its surface expression is regulated by a Golgi export signal in Kir2.1 (dominant in heteromers) and by Gβγ (promoting membrane targeting) antagonized by GDP-bound Gαo; in retinal ON bipolar cells Gβγ-dependent trafficking concentrates Kir2.4 at dendritic tips; the channel is pH-sensitive (activated by alkalinization) and partitions into lipid rafts with intermediate cholesterol sensitivity; in cancer cells, KCNJ14 knockdown suppresses proliferation, migration, and mTOR signaling.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"KCNJ14 encodes Kir2.4 (IRK4), a strongly inwardly rectifying K+ channel that controls neuronal excitability, demonstrated directly in hypoglossal motoneurons where Ba2+ block of the channel evokes tonic firing and increased spike frequency [#0]. Cloned from rat brain and human retina, the channel forms low-conductance (~15 pS) homomeric channels distinguished from other Kir2 members by markedly low affinity for Ba2+ and Cs+ blockers, and its currents are enhanced by extracellular alkalinization [#0, #1]. Kir2.4 physically co-assembles with Kir2.1 to form functional heteromeric channels with intermediate Ba2+ sensitivity, confirmed by reciprocal dominant-negative suppression, co-precipitation of epitope-tagged subunits, and tandem constructs [#3]; the conserved slide-helix–C-terminus gating interaction is shared across these heteromers, such that Andersen syndrome Kir2.1 mutations exert dominant-negative effects on Kir2.4 [#6]. Surface delivery is governed at the secretory pathway: expressed alone, Kir2.4 accumulates in the Golgi, and a tyrosine-dependent YXXΦ adaptin-binding Golgi-export signal in the Kir2.1 C-terminus is dominant in heteromers, setting the stoichiometry of channels reaching the membrane [#5]. Trafficking is further tuned by heterotrimeric G proteins: Kir2.4 binds Gαo1 (preferentially the GDP-bound form, which suppresses surface expression and current) while Gβγ promotes membrane targeting, and loss of Gβ3 reduces Kir2.4 concentration at the dendritic tips of retinal ON bipolar cells where the channel is normally enriched [#8, #9]. Unlike Kir2.1 and Kir2.3, Kir2.4 lacks a C-terminal PDZ-binding motif and does not couple to PSD-95 scaffolds [#2], but like other family members it partitions into cholesterol-rich lipid rafts with intermediate cholesterol sensitivity [#4]. In colorectal cancer cell lines, KCNJ14 knockdown reduces proliferation and migration and lowers mTOR pathway protein levels [#11].\",\n  \"teleology\": [\n    {\n      \"year\": 1998,\n      \"claim\": \"Established the molecular identity and signature pharmacology of Kir2.4 and tied it directly to control of motoneuron firing, answering whether this channel sets neuronal excitability.\",\n      \"evidence\": \"Cloning from rat brain, heterologous expression in oocytes and mammalian cells, patch clamp, and Ba2+ block in brainstem slice motoneurons\",\n      \"pmids\": [\"9592090\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Native channel composition (homomer vs heteromer) in motoneurons not resolved\", \"No structural basis for low Ba2+/Cs+ affinity\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Defined the human gene, its chromosomal locus, and pH sensitivity, establishing alkalinization-dependent activation as an intrinsic functional property.\",\n      \"evidence\": \"cDNA cloning from retinal library, oocyte two-electrode voltage clamp, Northern/in situ, somatic cell hybrid mapping\",\n      \"pmids\": [\"10942728\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular determinant of pH sensing not mapped\", \"Physiological context of pH modulation untested\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Showed Kir2.4 diverges from its paralogs by lacking a PDZ-binding motif, answering whether it uses PSD-95-family scaffolds for synaptic anchoring.\",\n      \"evidence\": \"Yeast two-hybrid against PSD-95/SAP90 PDZ domains and C-terminal motif sequence analysis\",\n      \"pmids\": [\"10627592\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Negative result from a single method/lab\", \"Alternative anchoring partners not identified\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Demonstrated that Kir2.4 is not obligately homomeric but co-assembles with Kir2.1 into heteromers with distinct Ba2+ sensitivity, redefining the native channel population.\",\n      \"evidence\": \"Dominant-negative co-expression, His6/FLAG co-precipitation in COS-7, tandem constructs, voltage clamp\",\n      \"pmids\": [\"12381809\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry of native heteromers not quantified\", \"Whether other Kir2 subunits also co-assemble untested here\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Placed Kir2.4 within cholesterol-rich lipid raft microdomains and ranked its cholesterol sensitivity among Kir2 family members, addressing membrane microenvironment dependence.\",\n      \"evidence\": \"Triton X-100 fractionation, Western blot, and whole-cell patch clamp after cholesterol manipulation\",\n      \"pmids\": [\"15465867\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Raft residency tested for one subunit among four compared\", \"Functional consequence of raft partitioning for Kir2.4 specifically not isolated\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Identified the secretory-pathway logic of heteromeric surface delivery, showing a dominant Kir2.1 Golgi-export signal overrides Kir2.4's Golgi retention.\",\n      \"evidence\": \"Kir2.1/Kir2.4 chimeras, subcellular fluorescence imaging, and site-directed mutagenesis of the YXXΦ motif\",\n      \"pmids\": [\"15827083\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Trafficking machinery (adaptin identity) acting on Kir2.4 not directly shown\", \"Whether Kir2.4 homomers ever reach the surface in native cells unresolved\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Showed the gating-critical slide-helix–C-terminus interaction is conserved in Kir2.4-containing heteromers, explaining how Kir2.1 disease mutations propagate dominant-negative effects.\",\n      \"evidence\": \"Voltage/patch clamp in oocytes and HEK293, chemiluminescence surface assay, PIP2 binding, yeast two-hybrid\",\n      \"pmids\": [\"17568571\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism defined primarily for Kir2.1; Kir2.4 one of three partners\", \"No disease link to KCNJ14 itself established\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Attributed a component of native inward rectifier current in pulmonary artery smooth muscle to Kir2.4 based on pharmacological fingerprint.\",\n      \"evidence\": \"Whole-cell/single-channel patch clamp, RT-PCR, and Ba2+ block comparison with cloned channels\",\n      \"pmids\": [\"17347781\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Contribution inferred from pharmacology, not genetic ablation\", \"Heteromeric composition in HPASM not defined\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Resolved a precise subcellular site for Kir2.4 in retinal ON bipolar cell dendritic tips, defining where the channel acts in the visual circuit.\",\n      \"evidence\": \"Grm6-GFP transgenic labeling, sorted-cell cDNA, and immunolocalization in retinal sections\",\n      \"pmids\": [\"18671302\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional role at dendritic tips not directly tested\", \"Mechanism of tip targeting not yet addressed in this study\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Established G-protein control of Kir2.4 trafficking, with Gβγ promoting and GDP-bound Gαo suppressing surface expression, and linked this to dendritic-tip enrichment in vivo.\",\n      \"evidence\": \"Yeast two-hybrid, co-IP in HEK293 and retina, oocyte voltage clamp with G-protein co-injection, membrane imaging, and Gβ3 knockout mouse retina immunofluorescence\",\n      \"pmids\": [\"23339194\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Upstream receptor driving Gαo/Gβγ regulation not identified\", \"Direct binding interface on Kir2.4 not mapped\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Revealed strong species divergence in Kir2.4 pharmacology, with zebrafish ortholog showing high Ba2+ sensitivity unlike the mammalian channel.\",\n      \"evidence\": \"HEK expression, patch clamp, and Ba2+ dose-response of zebrafish drKir2.4\",\n      \"pmids\": [\"25991088\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural residues responsible for the affinity shift not identified\", \"Mammalian inference limited by ortholog use\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Implicated KCNJ14 in cancer cell behavior, linking its knockdown to reduced proliferation/migration and lowered mTOR signaling.\",\n      \"evidence\": \"siRNA knockdown in HCT116/SW480, MTT, colony-forming, wound healing, transwell assays, and mTOR-pathway Western blot\",\n      \"pmids\": [\"36100894\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No rescue experiment to confirm specificity\", \"No demonstration that channel activity (vs non-conducting role) drives the phenotype\", \"Mechanistic link between K+ flux and mTOR not established\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How channel conductance versus trafficking/scaffolding roles of Kir2.4 are coupled to downstream signaling such as mTOR, and the identity of the upstream G-protein-coupled receptor regulating its surface expression, remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No receptor upstream of Gαo/Gβγ regulation identified\", \"Causal link between K+ conduction and mTOR signaling not established\", \"No structural model of Kir2.4 homomer or Kir2.1/2.4 heteromer\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005215\", \"supporting_discovery_ids\": [0, 1, 3]},\n      {\"term_id\": \"GO:0005216\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [5, 8, 9]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [0, 8]},\n      {\"term_id\": \"R-HSA-382551\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"complexes\": [\"Kir2.1/Kir2.4 heteromeric inward rectifier channel\"],\n    \"partners\": [\"KCNJ2\", \"GNAO1\", \"GNB3\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}