{"gene":"CNIH3","run_date":"2026-06-09T22:57:18","timeline":{"discoveries":[{"year":2019,"finding":"Cryo-EM structures of AMPAR in complex with CNIH3 revealed that CNIH3 lacks an extracellular domain and instead contains four membrane-spanning helices (contrary to previously predicted topology). The protein-protein interaction interface dictating channel modulation and surrounding lipids were identified, providing molecular mechanism for CNIH3-mediated ion channel modulation and AMPAR complex assembly.","method":"High-resolution cryo-electron microscopy structural determination","journal":"Science","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct structural determination by cryo-EM with functional validation of interaction interface; single rigorous study with multiple orthogonal structural analyses","pmids":["31806817"],"is_preprint":false},{"year":2013,"finding":"CNIH-2 and CNIH-3 selectively promote surface expression of GluA1-containing AMPARs (GluA1A2 heteromers) at hippocampal synapses. Conditional knockout of CNIH-2/-3 caused profound reduction of AMPAR synaptic transmission due to selective loss of GluA1-containing receptors, leaving a residual pool of GluA2A3 heteromers with faster kinetics. TARP γ-8 mediates the selective effect of CNIHs on GluA1 by preventing functional association of CNIHs with non-GluA1 subunits.","method":"Conditional knockout mice, electrophysiology, genetic epistasis with TARP γ-8","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 2 / Strong — conditional KO with defined synaptic phenotype, epistasis with γ-8, replicated across multiple experimental approaches in single rigorous study","pmids":["23522044"],"is_preprint":false},{"year":2012,"finding":"CNIH-2 and CNIH-3 (but not CNIH-1) slow deactivation and desensitization of both GluA2-containing and GluA2-lacking calcium-permeable AMPARs expressed in heterologous cells. They also enhance glutamate sensitivity, single-channel conductance, and calcium permeability of CP-AMPARs while decreasing their block by intracellular polyamines. Overexpression of CNIH-3 in oligodendrocyte precursor cells markedly slowed AMPAR desensitization.","method":"Electrophysiology in tsA201 cells and rat optic nerve oligodendrocyte precursor cells, CNIH-3 overexpression, anti-CNIH-2/3 surface labeling","journal":"The Journal of Neuroscience","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution with electrophysiology, multiple AMPAR subtypes tested, native cell overexpression validation, multiple orthogonal methods","pmids":["22815494"],"is_preprint":false},{"year":2014,"finding":"CNIH-3 forms a stable complex with tetrameric AMPARs and contributes to transmembrane density. Two clusters of conserved membrane-proximal residues in CNIHs contribute to AMPAR binding. Residues in the extracellular loop of CNIH-2/3 (absent in CNIH-1/4) are critical for both AMPAR interaction and gating modulation. The ligand-binding domain and a linker connecting it to the fourth membrane-spanning segment of AMPAR is the principal contact point with the CNIH-3 extracellular loop. A mutant CNIH-3 was identified that preserves AMPAR binding but has attenuated gating modulation, dissociating binding from gating.","method":"Single-particle electron microscopy, peptide array screening, in vitro mutagenesis, co-immunoprecipitation, electrophysiology","journal":"The Journal of Neuroscience","confidence":"High","confidence_rationale":"Tier 1 / Strong — multiple orthogonal methods including structural EM, peptide array, mutagenesis, and functional electrophysiology in single rigorous study","pmids":["25186755"],"is_preprint":false},{"year":2017,"finding":"Lipid-exposed residues in the transmembrane domain (TMD) of GluA2 are critical for CNIH3 function and complex stability. These residues overlap with AMPAR-stargazin contacts in cryo-EM structures. Mutating TMD residues had opposite effects on gating modulation when comparing CNIH3- versus stargazin-bound AMPARs (e.g., GluA2-A793F formed unstable complex with CNIH3 but showed gain-of-function; GluA2-C528L destabilized AMPAR-CNIH3 complex with overall loss of function). Both extracellular and TMD elements contribute independently to CNIH3-mediated gating modulation.","method":"Site-directed mutagenesis of GluA2 TMD residues, electrophysiology, detergent stability assays, comparison with stargazin modulation","journal":"The Journal of Physiology","confidence":"High","confidence_rationale":"Tier 1 / Strong — mutagenesis combined with functional electrophysiology and biochemical stability assays, multiple mutants tested with orthogonal readouts","pmids":["28815591"],"is_preprint":false},{"year":2012,"finding":"CNIH-2 serves an evolutionarily conserved role as a cargo exporter from the endoplasmic reticulum (ER), cycling continuously between ER and Golgi in a COPII-dependent manner. When GluA subunits interact with CNIH-2, they recruit it to the cell surface, breaking its ancestral confinement to the early secretory pathway. This mechanism was demonstrated to apply to the related CNIH-2 protein; CNIH-3 is identified as a constituent of native AMPARs by the same proteomic approach.","method":"Heterologous expression, live cell imaging, COPII-dependent export assay in HEK cells and primary rat neurons, co-immunoprecipitation","journal":"PloS ONE","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — live imaging, COPII dependency assay, co-IP in heterologous and primary neurons; findings primarily established for CNIH-2 with CNIH-3 as identified constituent","pmids":["22292017"],"is_preprint":false},{"year":2023,"finding":"CNIH-3 slows AMPAR receptor deactivation from the outset of current decay, consistent with its structural contact at the level of the pore (transmembrane domain). This mechanism is distinct from TARP γ2, which acts via the KGK site of the ligand-binding domain to slow desensitization onset. CNIH-3 modulation of AMPARs is unaffected by alternative splicing of the flip/flop cassette, unlike TARP γ2 modulation.","method":"Electrophysiology in heterologous cells expressing flip/flop splice variants with various auxiliary subunits","journal":"The Journal of Neuroscience","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — functional electrophysiology with mechanistic interpretation consistent with structural data; single lab, multiple splice variants and auxiliary subunit comparisons","pmids":["36931708"],"is_preprint":false},{"year":2023,"finding":"CNIH-3 only weakly enhances GluA1 tetramerization and does not enhance GluA2 tetramerization, in contrast to CNIH-2 which enhances tetramerization of both GluA1 and GluA2. CNIH-3's effect on tetramerization is mainly mediated through interactions with the AMPAR transmembrane domain. This defines a functional distinction between CNIH-2 and CNIH-3 in AMPAR biogenesis.","method":"Blue native PAGE tetramerization assay, surface expression assay, mutant AMPAR analysis in heterologous cells","journal":"The Journal of Biological Chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — biochemical tetramerization assay combined with surface expression measurements, single lab with multiple AMPAR subunit comparisons","pmids":["37673338"],"is_preprint":false},{"year":2021,"finding":"CNIH3 loss-of-function in female mice (Cnih3-/-) caused reduced dorsal hippocampal synapse density, enhanced expression of calcium-impermeable AMPAR (GluA2-containing) subunits in synaptosomes, attenuated long-term potentiation maintenance, and weakened short-term spatial memory. These deficits were most pronounced during the metestrus phase of the estrous cycle. Male Cnih3-/- mice were unaffected. Overexpression of Cnih3 in dorsal hippocampus improved short-term spatial memory in female but not male mice.","method":"Cnih3 knockout mice, viral overexpression, behavioral assays, immunoblotting of synaptosomal fractions, electrophysiology (LTP), super-resolution imaging (SEQUIN)","journal":"Biological Psychiatry","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (KO, OE, biochemistry, electrophysiology, super-resolution imaging, behavior) with sex-specific and estrous-specific phenotypic readouts","pmids":["34548146"],"is_preprint":false},{"year":2026,"finding":"Native calcium-permeable AMPARs purified from cerebellum (GluA1/GluA4-containing) associate primarily with CNIH3, with GluA4 occupying B/D positions and GluA1 at A/C positions. Cryo-EM structures in resting, active, and desensitized states characterized the gating mechanism of the native GluA1A4-CNIH3 complex, including a pseudo-4-fold configuration of the ligand-binding domain layer during desensitization.","method":"Antibody-based native AMPAR purification, cryo-EM structural determination in multiple functional states","journal":"Cell Research","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct structural determination of native complex in multiple gating states, combined with subunit composition determination by specific antibodies","pmids":["41840198"],"is_preprint":false},{"year":2013,"finding":"CNIH-2 and CNIH-3 show maximum mRNA and protein expression early after birth in rat brain, which then decline towards adulthood, contrasting with GluA1-4 upregulation during postnatal development. Despite reciprocal expression profiles, the ratio of CNIH-2/3 complexed with GluAs remains constant throughout development. Early in development there is an excess of AMPAR-free CNIH-2/3 that may serve the ancestral cargo exporter role, while during development the proportion integrated into AMPAR complexes increases.","method":"Quantitative PCR, western blotting, co-immunoprecipitation from developing rat brain tissue across postnatal timepoints","journal":"Molecular and Cellular Neurosciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — developmental protein and mRNA quantification combined with co-IP to assess AMPAR-bound vs. free fractions; single lab","pmids":["23403072"],"is_preprint":false},{"year":2023,"finding":"Cnih3 knockout in female mice drives broad transcriptomic differences between estrous cycle stages in the dorsal hippocampus, with estrous-responsive genes enriched in oligodendrocyte markers, estrogen response, potassium channels, and synaptic gene splicing. Cnih3 deletion accentuates sex-differential expression at diestrus and estrus, suggesting CNIH3 normally buffers against transcriptional effects of the estrous cycle.","method":"RNA-sequencing of dorsal hippocampus from Cnih3 knockout and wild-type female mice at each estrous cycle stage, and male mice","journal":"eNeuro","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — transcriptomic profiling with genetic KO across estrous cycle stages; single lab, single method (RNA-seq) but multiple conditions","pmids":["36849260"],"is_preprint":false},{"year":2026,"finding":"Cnih3 deletion impairs spatial memory (novel object recognition), operant learning in sucrose self-administration, delays acquisition of fentanyl intravenous self-administration (IVSA) in females, and blunts fentanyl intake during IVSA in both sexes in mice.","method":"Cnih3 knockout mice, behavioral battery (novel object recognition, sucrose SA, fentanyl IVSA, reversal learning), principal component analysis","journal":"Translational Psychiatry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KO with multiple behavioral readouts and PCA; single lab, behavioral phenotypes without molecular mechanism beyond AMPAR pathway placement","pmids":["42056073"],"is_preprint":false},{"year":2017,"finding":"A high-throughput screening pipeline identified compounds selective for GluA2-CNIH3 complexes versus GluA2-stargazin complexes. Candidate NAM (VU0612951) and PAM (VU0627849) compounds showed lower IC50/EC50 on stargazin and CNIH3 complexes than on GSG1L or AMPAR alone. VU0539491 showed NAM activity on GluA2(R)-CNIH3 and GluA2(Q) complexes and PAM activity on GluA2(Q)-GSG1L complexes, demonstrating pharmacological distinction of CNIH3-containing AMPAR complexes.","method":"Cell-based high-throughput screening with voltage-sensitive dye assay and calcium flux assay in HEK cells co-expressing GluA2 and auxiliary subunits","journal":"PloS ONE","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional cell-based assay with multiple orthogonal screening methods; single lab, pharmacological characterization of CNIH3-specific modulators","pmids":["28358902"],"is_preprint":false}],"current_model":"CNIH3 is an AMPA receptor (AMPAR) auxiliary subunit with four membrane-spanning helices (no extracellular domain) that directly binds AMPAR at the transmembrane domain and ligand-binding domain–TM4 linker interface; it slows deactivation and desensitization of AMPARs by acting at the pore level, selectively promotes surface trafficking of GluA1-containing AMPAR heteromers (regulated by TARP γ-8), enhances single-channel conductance and calcium permeability of calcium-permeable AMPARs, only weakly promotes AMPAR tetramerization compared to CNIH-2, and is required in females (but not males) for dorsal hippocampal synapse density, LTP maintenance, and spatial memory in an estrous cycle-dependent manner."},"narrative":{"mechanistic_narrative":"CNIH3 is an auxiliary subunit of AMPA-type glutamate receptors (AMPARs) that controls their gating, biophysical properties, and synaptic delivery [PMID:22815494, PMID:23522044]. Structurally it is an integral membrane protein composed of four membrane-spanning helices with no extracellular domain, contacting the AMPAR at the transmembrane domain and at a linker connecting the ligand-binding domain to the fourth transmembrane segment; this interface, together with surrounding lipids, dictates channel modulation and complex assembly [PMID:31806817, PMID:25186755, PMID:28815591]. Functionally, CNIH3 slows AMPAR deactivation and desensitization, enhances glutamate sensitivity, single-channel conductance, and calcium permeability of calcium-permeable AMPARs, and reduces their block by intracellular polyamines [PMID:22815494]. It acts from the outset of current decay through its pore-level transmembrane contact, mechanistically distinct from TARP γ2, and its modulation is insensitive to flip/flop alternative splicing [PMID:36931708]. CNIH3 promotes surface expression of GluA1-containing AMPAR heteromers, a selectivity imposed by TARP γ-8, and conditional loss of CNIH-2/-3 causes profound loss of GluA1-containing synaptic AMPARs [PMID:23522044]. Distinct from the paralog CNIH-2, CNIH3 only weakly enhances GluA1 tetramerization and does not enhance GluA2 tetramerization, defining a divergent role in AMPAR biogenesis [PMID:37673338]. At the systems level, CNIH3 is required in female mice for dorsal hippocampal synapse density, LTP maintenance, and spatial memory in an estrous cycle-dependent manner, and shapes operant and drug self-administration behaviors [PMID:34548146, PMID:42056073].","teleology":[{"year":2012,"claim":"Established CNIH3 as a functional AMPAR auxiliary subunit by showing it tunes receptor gating and conductance, answering whether cornichon proteins act on channel kinetics beyond trafficking.","evidence":"Electrophysiology in tsA201 cells and oligodendrocyte precursor cells across multiple AMPAR subtypes","pmids":["22815494"],"confidence":"High","gaps":["Did not resolve the structural basis of the interaction","Native complex composition not addressed","CNIH-2 vs CNIH-3 functional divergence not defined"]},{"year":2012,"claim":"Placed cornichons in the secretory pathway as conserved COPII-dependent ER cargo exporters, framing how AMPAR binding redirects them to the surface, though demonstrated mainly for CNIH-2.","evidence":"Live-cell imaging and COPII export assays in HEK cells and primary neurons with co-IP","pmids":["22292017"],"confidence":"Medium","gaps":["CNIH-3 export role inferred from CNIH-2","ER-cycling dynamics for CNIH3 specifically not measured"]},{"year":2013,"claim":"Defined the synaptic role of CNIH-2/-3 as selective promoters of GluA1-containing AMPARs and identified TARP γ-8 as the determinant of that selectivity, explaining subunit-specific AMPAR composition at synapses.","evidence":"Conditional knockout mice, electrophysiology, and genetic epistasis with TARP γ-8","pmids":["23522044"],"confidence":"High","gaps":["CNIH-2 vs CNIH-3 individual contributions not separated","Molecular basis of γ-8 gating of CNIH association unresolved"]},{"year":2013,"claim":"Mapped developmental expression showing CNIH-2/-3 peak early postnatally with an excess of AMPAR-free protein, suggesting a developmental shift from cargo-export to AMPAR-bound roles.","evidence":"qPCR, western blotting, and co-IP from developing rat brain across postnatal timepoints","pmids":["23403072"],"confidence":"Medium","gaps":["Functional consequence of free CNIH pool not tested","CNIH-2 and CNIH-3 not distinguished"]},{"year":2014,"claim":"Localized the binding interface to membrane-proximal residues and the CNIH-2/3-specific extracellular loop, and dissociated binding from gating via a mutant, establishing that interaction and modulation are separable functions.","evidence":"Single-particle EM, peptide array, mutagenesis, co-IP, and electrophysiology","pmids":["25186755"],"confidence":"High","gaps":["High-resolution topology not yet resolved","Lipid contributions not addressed"]},{"year":2017,"claim":"Identified GluA2 transmembrane lipid-exposed residues as critical for CNIH3 function and showed they overlap stargazin contacts with opposite gating effects, distinguishing CNIH3 from TARP modulation at the TMD.","evidence":"Site-directed mutagenesis of GluA2 TMD, electrophysiology, and detergent stability assays","pmids":["28815591"],"confidence":"High","gaps":["Mechanistic link between stability and gating incomplete","Native receptor relevance not tested"]},{"year":2017,"claim":"Demonstrated that CNIH3-containing AMPAR complexes are pharmacologically distinct, enabling auxiliary-subunit-selective small molecules and opening therapeutic targeting of specific AMPAR populations.","evidence":"Cell-based high-throughput screening with voltage-sensitive dye and calcium flux assays in HEK cells","pmids":["28358902"],"confidence":"Medium","gaps":["Compound selectivity not validated in native tissue","In vivo activity untested"]},{"year":2019,"claim":"Resolved the cryo-EM structure of the AMPAR-CNIH3 complex, overturning the predicted topology by showing four membrane-spanning helices and no extracellular domain, providing the molecular mechanism for channel modulation.","evidence":"High-resolution cryo-electron microscopy with functional validation of the interface","pmids":["31806817"],"confidence":"High","gaps":["Native subunit composition not captured","Conformational gating intermediates not resolved"]},{"year":2021,"claim":"Revealed a sex- and estrous-cycle-specific physiological requirement for CNIH3 in female dorsal hippocampal synapse density, LTP, and spatial memory, linking the molecular AMPAR function to behavior.","evidence":"Cnih3 knockout and viral overexpression mice, behavior, synaptosome immunoblotting, LTP, and super-resolution imaging","pmids":["34548146"],"confidence":"High","gaps":["Mechanism of sex specificity unresolved","Link between AMPAR subunit shift and behavior not causally proven"]},{"year":2023,"claim":"Clarified the gating mechanism distinction by showing CNIH3 slows deactivation from the outset via a pore-level contact, insensitive to flip/flop splicing unlike TARP γ2.","evidence":"Electrophysiology of flip/flop splice variants with various auxiliary subunits in heterologous cells","pmids":["36931708"],"confidence":"Medium","gaps":["Single-lab functional inference","Direct structural correlate of the early-decay effect not shown"]},{"year":2023,"claim":"Distinguished CNIH3 from CNIH-2 in biogenesis by showing CNIH3 only weakly promotes GluA1 tetramerization and not GluA2, mainly via TMD interactions, defining paralog-specific assembly roles.","evidence":"Blue native PAGE tetramerization and surface expression assays with mutant AMPARs","pmids":["37673338"],"confidence":"Medium","gaps":["Native tetramerization context not assessed","Structural basis of weak activity unresolved"]},{"year":2023,"claim":"Showed CNIH3 buffers estrous-cycle-driven hippocampal transcription, with its deletion amplifying sex-differential and cycle-stage gene expression, extending its role beyond direct AMPAR modulation.","evidence":"RNA-sequencing of dorsal hippocampus from Cnih3 knockout and wild-type mice across estrous stages","pmids":["36849260"],"confidence":"Medium","gaps":["Causal mechanism linking AMPAR function to transcription unknown","Single method (RNA-seq)"]},{"year":2026,"claim":"Determined cryo-EM structures of a native cerebellar GluA1/GluA4-CNIH3 complex across gating states, fixing the subunit arrangement and gating conformations of a physiological CNIH3 complex.","evidence":"Antibody-based native AMPAR purification and cryo-EM in resting, active, and desensitized states","pmids":["41840198"],"confidence":"High","gaps":["Generalizability to hippocampal GluA1A2 complexes untested","Dynamics in membrane environment not captured"]},{"year":2026,"claim":"Extended CNIH3's behavioral relevance to learning and drug-taking, showing deletion impairs spatial memory and operant learning and alters fentanyl self-administration in a partly sex-dependent manner.","evidence":"Cnih3 knockout mice with a behavioral battery and principal component analysis","pmids":["42056073"],"confidence":"Medium","gaps":["No molecular mechanism beyond AMPAR pathway placement","Circuit locus of drug-intake effect undefined"]},{"year":null,"claim":"How CNIH3's molecular AMPAR modulation produces sex- and estrous-cycle-specific synaptic and behavioral phenotypes remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["Mechanism linking estrous hormones to CNIH3 function unknown","Causal chain from AMPAR subunit composition to memory not established","Cell-type-specific contributions undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[2,1,6]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[0,3,9]},{"term_id":"GO:0038024","term_label":"cargo receptor activity","supporting_discovery_ids":[5,1]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[1,0,2]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[5]}],"pathway":[{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[1,8]},{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[1,5]}],"complexes":["AMPA receptor complex"],"partners":["GRIA1","GRIA2","GRIA4","CACNG8","CNIH2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8TBE1","full_name":"Protein cornichon homolog 3","aliases":["Cornichon family AMPA receptor auxiliary protein 3"],"length_aa":160,"mass_kda":19.0,"function":"Regulates the trafficking and gating properties of AMPA-selective glutamate receptors (AMPARs). Promotes their targeting to the cell membrane and synapses and modulates their gating properties by regulating their rates of activation, deactivation and desensitization","subcellular_location":"Postsynaptic cell membrane","url":"https://www.uniprot.org/uniprotkb/Q8TBE1/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/CNIH3","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/CNIH3","total_profiled":1310},"omim":[{"mim_id":"611288","title":"CORNICHON FAMILY AMPA RECEPTOR AUXILIARY PROTEIN 2; CNIH2","url":"https://www.omim.org/entry/611288"},{"mim_id":"611287","title":"CORNICHON FAMILY AMPA RECEPTOR AUXILIARY PROTEIN 1; CNIH1","url":"https://www.omim.org/entry/611287"},{"mim_id":"138248","title":"GLUTAMATE RECEPTOR, IONOTROPIC, AMPA 1; GRIA1","url":"https://www.omim.org/entry/138248"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Group enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"brain","ntpm":10.9},{"tissue":"pancreas","ntpm":7.4}],"url":"https://www.proteinatlas.org/search/CNIH3"},"hgnc":{"alias_symbol":["FLJ38993","CNIH-3"],"prev_symbol":[]},"alphafold":{"accession":"Q8TBE1","domains":[{"cath_id":"-","chopping":"4-158","consensus_level":"high","plddt":85.0114,"start":4,"end":158}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8TBE1","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8TBE1-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8TBE1-F1-predicted_aligned_error_v6.png","plddt_mean":84.5},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CNIH3","jax_strain_url":"https://www.jax.org/strain/search?query=CNIH3"},"sequence":{"accession":"Q8TBE1","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8TBE1.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8TBE1/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8TBE1"}},"corpus_meta":[{"pmid":"23522044","id":"PMC_23522044","title":"Cornichon 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Cornichons in the Biogenesis and Functioning of Monovalent-Cation Transport Systems.","date":"2024","source":"Physiological research","url":"https://pubmed.ncbi.nlm.nih.gov/38836370","citation_count":2,"is_preprint":false},{"pmid":"36798164","id":"PMC_36798164","title":"Differential regulation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) receptor tetramerization by auxiliary subunits.","date":"2023","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/36798164","citation_count":1,"is_preprint":false},{"pmid":"41840198","id":"PMC_41840198","title":"Assembly and gating mechanism of native AMPA receptors from the cerebellum.","date":"2026","source":"Cell research","url":"https://pubmed.ncbi.nlm.nih.gov/41840198","citation_count":1,"is_preprint":false},{"pmid":"41292766","id":"PMC_41292766","title":"Cornichon Homolog-3 (Cnih3) deletion impairs spatial memory, reward-cue association, and fentanyl self-administration 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The protein-protein interaction interface dictating channel modulation and surrounding lipids were identified, providing molecular mechanism for CNIH3-mediated ion channel modulation and AMPAR complex assembly.\",\n      \"method\": \"High-resolution cryo-electron microscopy structural determination\",\n      \"journal\": \"Science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct structural determination by cryo-EM with functional validation of interaction interface; single rigorous study with multiple orthogonal structural analyses\",\n      \"pmids\": [\"31806817\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"CNIH-2 and CNIH-3 selectively promote surface expression of GluA1-containing AMPARs (GluA1A2 heteromers) at hippocampal synapses. Conditional knockout of CNIH-2/-3 caused profound reduction of AMPAR synaptic transmission due to selective loss of GluA1-containing receptors, leaving a residual pool of GluA2A3 heteromers with faster kinetics. TARP γ-8 mediates the selective effect of CNIHs on GluA1 by preventing functional association of CNIHs with non-GluA1 subunits.\",\n      \"method\": \"Conditional knockout mice, electrophysiology, genetic epistasis with TARP γ-8\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — conditional KO with defined synaptic phenotype, epistasis with γ-8, replicated across multiple experimental approaches in single rigorous study\",\n      \"pmids\": [\"23522044\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"CNIH-2 and CNIH-3 (but not CNIH-1) slow deactivation and desensitization of both GluA2-containing and GluA2-lacking calcium-permeable AMPARs expressed in heterologous cells. They also enhance glutamate sensitivity, single-channel conductance, and calcium permeability of CP-AMPARs while decreasing their block by intracellular polyamines. Overexpression of CNIH-3 in oligodendrocyte precursor cells markedly slowed AMPAR desensitization.\",\n      \"method\": \"Electrophysiology in tsA201 cells and rat optic nerve oligodendrocyte precursor cells, CNIH-3 overexpression, anti-CNIH-2/3 surface labeling\",\n      \"journal\": \"The Journal of Neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution with electrophysiology, multiple AMPAR subtypes tested, native cell overexpression validation, multiple orthogonal methods\",\n      \"pmids\": [\"22815494\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"CNIH-3 forms a stable complex with tetrameric AMPARs and contributes to transmembrane density. Two clusters of conserved membrane-proximal residues in CNIHs contribute to AMPAR binding. Residues in the extracellular loop of CNIH-2/3 (absent in CNIH-1/4) are critical for both AMPAR interaction and gating modulation. The ligand-binding domain and a linker connecting it to the fourth membrane-spanning segment of AMPAR is the principal contact point with the CNIH-3 extracellular loop. A mutant CNIH-3 was identified that preserves AMPAR binding but has attenuated gating modulation, dissociating binding from gating.\",\n      \"method\": \"Single-particle electron microscopy, peptide array screening, in vitro mutagenesis, co-immunoprecipitation, electrophysiology\",\n      \"journal\": \"The Journal of Neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — multiple orthogonal methods including structural EM, peptide array, mutagenesis, and functional electrophysiology in single rigorous study\",\n      \"pmids\": [\"25186755\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Lipid-exposed residues in the transmembrane domain (TMD) of GluA2 are critical for CNIH3 function and complex stability. These residues overlap with AMPAR-stargazin contacts in cryo-EM structures. Mutating TMD residues had opposite effects on gating modulation when comparing CNIH3- versus stargazin-bound AMPARs (e.g., GluA2-A793F formed unstable complex with CNIH3 but showed gain-of-function; GluA2-C528L destabilized AMPAR-CNIH3 complex with overall loss of function). Both extracellular and TMD elements contribute independently to CNIH3-mediated gating modulation.\",\n      \"method\": \"Site-directed mutagenesis of GluA2 TMD residues, electrophysiology, detergent stability assays, comparison with stargazin modulation\",\n      \"journal\": \"The Journal of Physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — mutagenesis combined with functional electrophysiology and biochemical stability assays, multiple mutants tested with orthogonal readouts\",\n      \"pmids\": [\"28815591\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"CNIH-2 serves an evolutionarily conserved role as a cargo exporter from the endoplasmic reticulum (ER), cycling continuously between ER and Golgi in a COPII-dependent manner. When GluA subunits interact with CNIH-2, they recruit it to the cell surface, breaking its ancestral confinement to the early secretory pathway. This mechanism was demonstrated to apply to the related CNIH-2 protein; CNIH-3 is identified as a constituent of native AMPARs by the same proteomic approach.\",\n      \"method\": \"Heterologous expression, live cell imaging, COPII-dependent export assay in HEK cells and primary rat neurons, co-immunoprecipitation\",\n      \"journal\": \"PloS ONE\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — live imaging, COPII dependency assay, co-IP in heterologous and primary neurons; findings primarily established for CNIH-2 with CNIH-3 as identified constituent\",\n      \"pmids\": [\"22292017\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"CNIH-3 slows AMPAR receptor deactivation from the outset of current decay, consistent with its structural contact at the level of the pore (transmembrane domain). This mechanism is distinct from TARP γ2, which acts via the KGK site of the ligand-binding domain to slow desensitization onset. CNIH-3 modulation of AMPARs is unaffected by alternative splicing of the flip/flop cassette, unlike TARP γ2 modulation.\",\n      \"method\": \"Electrophysiology in heterologous cells expressing flip/flop splice variants with various auxiliary subunits\",\n      \"journal\": \"The Journal of Neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — functional electrophysiology with mechanistic interpretation consistent with structural data; single lab, multiple splice variants and auxiliary subunit comparisons\",\n      \"pmids\": [\"36931708\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"CNIH-3 only weakly enhances GluA1 tetramerization and does not enhance GluA2 tetramerization, in contrast to CNIH-2 which enhances tetramerization of both GluA1 and GluA2. CNIH-3's effect on tetramerization is mainly mediated through interactions with the AMPAR transmembrane domain. This defines a functional distinction between CNIH-2 and CNIH-3 in AMPAR biogenesis.\",\n      \"method\": \"Blue native PAGE tetramerization assay, surface expression assay, mutant AMPAR analysis in heterologous cells\",\n      \"journal\": \"The Journal of Biological Chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — biochemical tetramerization assay combined with surface expression measurements, single lab with multiple AMPAR subunit comparisons\",\n      \"pmids\": [\"37673338\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"CNIH3 loss-of-function in female mice (Cnih3-/-) caused reduced dorsal hippocampal synapse density, enhanced expression of calcium-impermeable AMPAR (GluA2-containing) subunits in synaptosomes, attenuated long-term potentiation maintenance, and weakened short-term spatial memory. These deficits were most pronounced during the metestrus phase of the estrous cycle. Male Cnih3-/- mice were unaffected. Overexpression of Cnih3 in dorsal hippocampus improved short-term spatial memory in female but not male mice.\",\n      \"method\": \"Cnih3 knockout mice, viral overexpression, behavioral assays, immunoblotting of synaptosomal fractions, electrophysiology (LTP), super-resolution imaging (SEQUIN)\",\n      \"journal\": \"Biological Psychiatry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (KO, OE, biochemistry, electrophysiology, super-resolution imaging, behavior) with sex-specific and estrous-specific phenotypic readouts\",\n      \"pmids\": [\"34548146\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"Native calcium-permeable AMPARs purified from cerebellum (GluA1/GluA4-containing) associate primarily with CNIH3, with GluA4 occupying B/D positions and GluA1 at A/C positions. Cryo-EM structures in resting, active, and desensitized states characterized the gating mechanism of the native GluA1A4-CNIH3 complex, including a pseudo-4-fold configuration of the ligand-binding domain layer during desensitization.\",\n      \"method\": \"Antibody-based native AMPAR purification, cryo-EM structural determination in multiple functional states\",\n      \"journal\": \"Cell Research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct structural determination of native complex in multiple gating states, combined with subunit composition determination by specific antibodies\",\n      \"pmids\": [\"41840198\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"CNIH-2 and CNIH-3 show maximum mRNA and protein expression early after birth in rat brain, which then decline towards adulthood, contrasting with GluA1-4 upregulation during postnatal development. Despite reciprocal expression profiles, the ratio of CNIH-2/3 complexed with GluAs remains constant throughout development. Early in development there is an excess of AMPAR-free CNIH-2/3 that may serve the ancestral cargo exporter role, while during development the proportion integrated into AMPAR complexes increases.\",\n      \"method\": \"Quantitative PCR, western blotting, co-immunoprecipitation from developing rat brain tissue across postnatal timepoints\",\n      \"journal\": \"Molecular and Cellular Neurosciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — developmental protein and mRNA quantification combined with co-IP to assess AMPAR-bound vs. free fractions; single lab\",\n      \"pmids\": [\"23403072\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Cnih3 knockout in female mice drives broad transcriptomic differences between estrous cycle stages in the dorsal hippocampus, with estrous-responsive genes enriched in oligodendrocyte markers, estrogen response, potassium channels, and synaptic gene splicing. Cnih3 deletion accentuates sex-differential expression at diestrus and estrus, suggesting CNIH3 normally buffers against transcriptional effects of the estrous cycle.\",\n      \"method\": \"RNA-sequencing of dorsal hippocampus from Cnih3 knockout and wild-type female mice at each estrous cycle stage, and male mice\",\n      \"journal\": \"eNeuro\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — transcriptomic profiling with genetic KO across estrous cycle stages; single lab, single method (RNA-seq) but multiple conditions\",\n      \"pmids\": [\"36849260\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"Cnih3 deletion impairs spatial memory (novel object recognition), operant learning in sucrose self-administration, delays acquisition of fentanyl intravenous self-administration (IVSA) in females, and blunts fentanyl intake during IVSA in both sexes in mice.\",\n      \"method\": \"Cnih3 knockout mice, behavioral battery (novel object recognition, sucrose SA, fentanyl IVSA, reversal learning), principal component analysis\",\n      \"journal\": \"Translational Psychiatry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO with multiple behavioral readouts and PCA; single lab, behavioral phenotypes without molecular mechanism beyond AMPAR pathway placement\",\n      \"pmids\": [\"42056073\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"A high-throughput screening pipeline identified compounds selective for GluA2-CNIH3 complexes versus GluA2-stargazin complexes. Candidate NAM (VU0612951) and PAM (VU0627849) compounds showed lower IC50/EC50 on stargazin and CNIH3 complexes than on GSG1L or AMPAR alone. VU0539491 showed NAM activity on GluA2(R)-CNIH3 and GluA2(Q) complexes and PAM activity on GluA2(Q)-GSG1L complexes, demonstrating pharmacological distinction of CNIH3-containing AMPAR complexes.\",\n      \"method\": \"Cell-based high-throughput screening with voltage-sensitive dye assay and calcium flux assay in HEK cells co-expressing GluA2 and auxiliary subunits\",\n      \"journal\": \"PloS ONE\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional cell-based assay with multiple orthogonal screening methods; single lab, pharmacological characterization of CNIH3-specific modulators\",\n      \"pmids\": [\"28358902\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CNIH3 is an AMPA receptor (AMPAR) auxiliary subunit with four membrane-spanning helices (no extracellular domain) that directly binds AMPAR at the transmembrane domain and ligand-binding domain–TM4 linker interface; it slows deactivation and desensitization of AMPARs by acting at the pore level, selectively promotes surface trafficking of GluA1-containing AMPAR heteromers (regulated by TARP γ-8), enhances single-channel conductance and calcium permeability of calcium-permeable AMPARs, only weakly promotes AMPAR tetramerization compared to CNIH-2, and is required in females (but not males) for dorsal hippocampal synapse density, LTP maintenance, and spatial memory in an estrous cycle-dependent manner.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"CNIH3 is an auxiliary subunit of AMPA-type glutamate receptors (AMPARs) that controls their gating, biophysical properties, and synaptic delivery [#2, #1]. Structurally it is an integral membrane protein composed of four membrane-spanning helices with no extracellular domain, contacting the AMPAR at the transmembrane domain and at a linker connecting the ligand-binding domain to the fourth transmembrane segment; this interface, together with surrounding lipids, dictates channel modulation and complex assembly [#0, #3, #4]. Functionally, CNIH3 slows AMPAR deactivation and desensitization, enhances glutamate sensitivity, single-channel conductance, and calcium permeability of calcium-permeable AMPARs, and reduces their block by intracellular polyamines [#2]. It acts from the outset of current decay through its pore-level transmembrane contact, mechanistically distinct from TARP \\u03b32, and its modulation is insensitive to flip/flop alternative splicing [#6]. CNIH3 promotes surface expression of GluA1-containing AMPAR heteromers, a selectivity imposed by TARP \\u03b3-8, and conditional loss of CNIH-2/-3 causes profound loss of GluA1-containing synaptic AMPARs [#1]. Distinct from the paralog CNIH-2, CNIH3 only weakly enhances GluA1 tetramerization and does not enhance GluA2 tetramerization, defining a divergent role in AMPAR biogenesis [#7]. At the systems level, CNIH3 is required in female mice for dorsal hippocampal synapse density, LTP maintenance, and spatial memory in an estrous cycle-dependent manner, and shapes operant and drug self-administration behaviors [#8, #12].\",\n  \"teleology\": [\n    {\n      \"year\": 2012,\n      \"claim\": \"Established CNIH3 as a functional AMPAR auxiliary subunit by showing it tunes receptor gating and conductance, answering whether cornichon proteins act on channel kinetics beyond trafficking.\",\n      \"evidence\": \"Electrophysiology in tsA201 cells and oligodendrocyte precursor cells across multiple AMPAR subtypes\",\n      \"pmids\": [\"22815494\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve the structural basis of the interaction\", \"Native complex composition not addressed\", \"CNIH-2 vs CNIH-3 functional divergence not defined\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Placed cornichons in the secretory pathway as conserved COPII-dependent ER cargo exporters, framing how AMPAR binding redirects them to the surface, though demonstrated mainly for CNIH-2.\",\n      \"evidence\": \"Live-cell imaging and COPII export assays in HEK cells and primary neurons with co-IP\",\n      \"pmids\": [\"22292017\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"CNIH-3 export role inferred from CNIH-2\", \"ER-cycling dynamics for CNIH3 specifically not measured\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Defined the synaptic role of CNIH-2/-3 as selective promoters of GluA1-containing AMPARs and identified TARP \\u03b3-8 as the determinant of that selectivity, explaining subunit-specific AMPAR composition at synapses.\",\n      \"evidence\": \"Conditional knockout mice, electrophysiology, and genetic epistasis with TARP \\u03b3-8\",\n      \"pmids\": [\"23522044\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"CNIH-2 vs CNIH-3 individual contributions not separated\", \"Molecular basis of \\u03b3-8 gating of CNIH association unresolved\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Mapped developmental expression showing CNIH-2/-3 peak early postnatally with an excess of AMPAR-free protein, suggesting a developmental shift from cargo-export to AMPAR-bound roles.\",\n      \"evidence\": \"qPCR, western blotting, and co-IP from developing rat brain across postnatal timepoints\",\n      \"pmids\": [\"23403072\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of free CNIH pool not tested\", \"CNIH-2 and CNIH-3 not distinguished\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Localized the binding interface to membrane-proximal residues and the CNIH-2/3-specific extracellular loop, and dissociated binding from gating via a mutant, establishing that interaction and modulation are separable functions.\",\n      \"evidence\": \"Single-particle EM, peptide array, mutagenesis, co-IP, and electrophysiology\",\n      \"pmids\": [\"25186755\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"High-resolution topology not yet resolved\", \"Lipid contributions not addressed\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Identified GluA2 transmembrane lipid-exposed residues as critical for CNIH3 function and showed they overlap stargazin contacts with opposite gating effects, distinguishing CNIH3 from TARP modulation at the TMD.\",\n      \"evidence\": \"Site-directed mutagenesis of GluA2 TMD, electrophysiology, and detergent stability assays\",\n      \"pmids\": [\"28815591\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanistic link between stability and gating incomplete\", \"Native receptor relevance not tested\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Demonstrated that CNIH3-containing AMPAR complexes are pharmacologically distinct, enabling auxiliary-subunit-selective small molecules and opening therapeutic targeting of specific AMPAR populations.\",\n      \"evidence\": \"Cell-based high-throughput screening with voltage-sensitive dye and calcium flux assays in HEK cells\",\n      \"pmids\": [\"28358902\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Compound selectivity not validated in native tissue\", \"In vivo activity untested\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Resolved the cryo-EM structure of the AMPAR-CNIH3 complex, overturning the predicted topology by showing four membrane-spanning helices and no extracellular domain, providing the molecular mechanism for channel modulation.\",\n      \"evidence\": \"High-resolution cryo-electron microscopy with functional validation of the interface\",\n      \"pmids\": [\"31806817\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Native subunit composition not captured\", \"Conformational gating intermediates not resolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Revealed a sex- and estrous-cycle-specific physiological requirement for CNIH3 in female dorsal hippocampal synapse density, LTP, and spatial memory, linking the molecular AMPAR function to behavior.\",\n      \"evidence\": \"Cnih3 knockout and viral overexpression mice, behavior, synaptosome immunoblotting, LTP, and super-resolution imaging\",\n      \"pmids\": [\"34548146\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of sex specificity unresolved\", \"Link between AMPAR subunit shift and behavior not causally proven\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Clarified the gating mechanism distinction by showing CNIH3 slows deactivation from the outset via a pore-level contact, insensitive to flip/flop splicing unlike TARP \\u03b32.\",\n      \"evidence\": \"Electrophysiology of flip/flop splice variants with various auxiliary subunits in heterologous cells\",\n      \"pmids\": [\"36931708\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab functional inference\", \"Direct structural correlate of the early-decay effect not shown\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Distinguished CNIH3 from CNIH-2 in biogenesis by showing CNIH3 only weakly promotes GluA1 tetramerization and not GluA2, mainly via TMD interactions, defining paralog-specific assembly roles.\",\n      \"evidence\": \"Blue native PAGE tetramerization and surface expression assays with mutant AMPARs\",\n      \"pmids\": [\"37673338\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Native tetramerization context not assessed\", \"Structural basis of weak activity unresolved\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Showed CNIH3 buffers estrous-cycle-driven hippocampal transcription, with its deletion amplifying sex-differential and cycle-stage gene expression, extending its role beyond direct AMPAR modulation.\",\n      \"evidence\": \"RNA-sequencing of dorsal hippocampus from Cnih3 knockout and wild-type mice across estrous stages\",\n      \"pmids\": [\"36849260\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Causal mechanism linking AMPAR function to transcription unknown\", \"Single method (RNA-seq)\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Determined cryo-EM structures of a native cerebellar GluA1/GluA4-CNIH3 complex across gating states, fixing the subunit arrangement and gating conformations of a physiological CNIH3 complex.\",\n      \"evidence\": \"Antibody-based native AMPAR purification and cryo-EM in resting, active, and desensitized states\",\n      \"pmids\": [\"41840198\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Generalizability to hippocampal GluA1A2 complexes untested\", \"Dynamics in membrane environment not captured\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Extended CNIH3's behavioral relevance to learning and drug-taking, showing deletion impairs spatial memory and operant learning and alters fentanyl self-administration in a partly sex-dependent manner.\",\n      \"evidence\": \"Cnih3 knockout mice with a behavioral battery and principal component analysis\",\n      \"pmids\": [\"42056073\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No molecular mechanism beyond AMPAR pathway placement\", \"Circuit locus of drug-intake effect undefined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How CNIH3's molecular AMPAR modulation produces sex- and estrous-cycle-specific synaptic and behavioral phenotypes remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking estrous hormones to CNIH3 function unknown\", \"Causal chain from AMPAR subunit composition to memory not established\", \"Cell-type-specific contributions undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [2, 1, 6]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [0, 3, 9]},\n      {\"term_id\": \"GO:0038024\", \"supporting_discovery_ids\": [5, 1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [1, 0, 2]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [1, 8]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [1, 5]}\n    ],\n    \"complexes\": [\"AMPA receptor complex\"],\n    \"partners\": [\"GRIA1\", \"GRIA2\", \"GRIA4\", \"CACNG8\", \"CNIH2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}