{"gene":"GPHN","run_date":"2026-06-10T01:55:21","timeline":{"discoveries":[{"year":2003,"finding":"GlyR-gephyrin binding is dependent on the presence of an intact C-terminal MoeA homology (E-domain) of gephyrin. The N10Y missense mutation and alternative splicing of GPHN transcripts do not disrupt GlyR-gephyrin interactions or collybistin-induced cell-surface clustering.","method":"Yeast two-hybrid, functional clustering assay, RT-PCR isoform analysis, mutagenesis","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — yeast two-hybrid plus functional clustering assay with mutagenesis, single lab","pmids":["12684523"],"is_preprint":false},{"year":2003,"finding":"Gephyrin (encoded by GEPH/GPHN) is required during molybdenum cofactor assembly for insertion of molybdenum into the cofactor; loss-of-function mutations abrogate all molybdoenzyme activities.","method":"Human mutation analysis combined with biochemical phenotyping of molybdoenzyme activities in patients","journal":"Human mutation","confidence":"Medium","confidence_rationale":"Tier 2 / Strong — replicated across multiple patient families and two review papers drawing on biochemical phenotyping, but primarily genetic/biochemical phenotype rather than in vitro reconstitution","pmids":["12754701","21031595"],"is_preprint":false},{"year":2001,"finding":"Gephyrin functions as a peripheral membrane scaffolding protein anchoring glycine receptors to subsynaptic microtubules; it also plays a role in GABA-A receptor localization at the synapse and in molybdenum cofactor biosynthesis, as established by knockout mouse phenotypes.","method":"Knockout mouse analysis, gene structure determination, localization studies","journal":"Gene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — knockout mouse model with defined dual phenotypes (receptor clustering loss + MoCo deficiency), single study","pmids":["11418245"],"is_preprint":false},{"year":2001,"finding":"In a translocation t(11;14)(q23;q24)-associated leukemia, the GPHN C-terminal half (including a tubulin-binding site and MoeA homology domain) is fused to MLL AT-hook and DNA methyltransferase homology domains, generating an MLL-GPHN fusion protein. Genomic breakpoint analysis identified topoisomerase-II DNA-binding sites spanning both breakpoints, suggesting VP16/topoisomerase-II-induced double-strand breaks and non-homologous end joining as the generation mechanism.","method":"cDNA library screening, fusion transcript identification, genomic breakpoint analysis","journal":"Genes, chromosomes & cancer","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — direct molecular characterization of fusion gene in a single patient, no functional reconstitution of the fusion protein","pmids":["11579461"],"is_preprint":false},{"year":2024,"finding":"Gephyrin assembles with heteromeric α2β glycine receptors (GlyRs) into micron-sized clusters at the plasma membrane. Neuroligin-2 further increases cluster sizes and GlyR concentration. A positively charged N-terminus sequence of the GlyR β subunit is essential for glycine affinity modulation through clustering. Ligand re-binding to adjacent clustered GlyRs alters kinetics but not chemical equilibrium.","method":"Heterologous expression clustering assay, electrophysiology, mutagenesis of GlyR β subunit N-terminus","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional reconstitution in heterologous system with mutagenesis and electrophysiology, preprint single lab","pmids":["bio_10.1101_2024.10.17.618879"],"is_preprint":true},{"year":2024,"finding":"In zebrafish, Gephyrin (Gphnb) is enriched in myelin on GABAergic and glycinergic axons. Loss of gphnb causes longer myelin sheaths specifically on GABAergic axons and shifts myelin placement toward glutamatergic axons at the expense of GABAergic axons, indicating gephyrin mediates selective axon-class-dependent myelination by oligodendrocytes.","method":"Zebrafish gphnb loss-of-function genetics, imaging of myelin sheath length and distribution per axon class","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — clean genetic KO in zebrafish with specific cellular phenotype, preprint single lab, no biochemical mechanism for oligodendrocyte interaction identified","pmids":["bio_10.1101_2024.10.02.616365"],"is_preprint":true},{"year":2025,"finding":"Cryo-EM combined with biochemical reconstitution and mutational analyses shows that full-length gephyrin forms a stable dimer as the basic oligomeric unit, which further assembles into linear and oblique tetramers and linear hexamers. A critical segment of the flexible central linker adopts two distinct conformations, one of which occludes the receptor-binding site, and this segment harbors key phosphorylation sites, providing a mechanistic link between phosphorylation state, linker conformation, and receptor binding.","method":"Cryo-electron microscopy, biochemical reconstitution, mutational analysis","journal":"bioRxiv","confidence":"High","confidence_rationale":"Tier 1 / Moderate — cryo-EM structure with reconstitution and mutagenesis in a single rigorous study; preprint but multiple orthogonal methods","pmids":["bio_10.1101_2025.09.01.673457"],"is_preprint":true},{"year":2025,"finding":"Collybistin induces gephyrin self-oligomerization into a high-molecular-weight (>5 MDa) gephyrin-collybistin complex at GABAergic synapses. Plasma-membrane phosphoinositides promote complex formation and are critical for membrane targeting and stabilization. Gephyrin phosphorylation at Ser325 abolishes complex formation with collybistin, impairing collybistin-dependent gephyrin clustering at GABAergic synapses.","method":"Biochemical reconstitution of gephyrin-collybistin complex, phosphorylation site mutagenesis (Ser325), phosphoinositide binding assays, synaptic clustering assays","journal":"bioRxiv","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution of complex with mutagenesis and lipid binding assays, multiple orthogonal methods in single preprint study","pmids":["bio_10.1101_2025.01.20.633899"],"is_preprint":true},{"year":2025,"finding":"WNK1 kinase (and its effector SPAK) directly phosphorylates two previously uncharacterized residues in the central linker region of gephyrin. This phosphorylation controls GABA-A receptor synaptic diffusion, clustering, membrane stability, and endocytosis at inhibitory synapses. Activation of WNK signaling stabilizes GABA-A Rs at inhibitory synapses; inhibition enhances receptor internalization. Expression of a phospho-mimetic form of gephyrin at WNK-targeted sites produces anxiolytic effects in vivo.","method":"Phosphorylation site identification and mutagenesis, live imaging of receptor diffusion, electrophysiology of GABAergic currents, in vivo behavioral assay (anxiety)","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — phospho-mimetic/phospho-null mutagenesis combined with receptor trafficking assays and in vivo behavior, preprint single lab","pmids":["bio_10.1101_2025.09.05.674425"],"is_preprint":true},{"year":2025,"finding":"A knock-in mouse model of the gephyrin microdeletion Δ199-233 (within the C-domain, removing a region that includes the S-palmitoylation site at Cys212) disrupts synaptic targeting of gephyrin in dissociated hippocampal neurons. Despite unexpectedly facilitating receptor interaction in vitro, inhibitory signal transmission is reduced. Compensatory changes occur at excitatory synapses (smaller but more numerous PSD-95 clusters). Loss of the C-domain palmitoylation site is required for correct synaptic targeting.","method":"Knock-in mouse model, immunofluorescence of synaptic clustering in hippocampal neurons, electrophysiology of inhibitory transmission, PSD-95 cluster analysis","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo knock-in model with cellular and electrophysiological readouts, multiple phenotypic analyses; preprint single lab","pmids":["bio_10.1101_2025.08.26.672322"],"is_preprint":true},{"year":2024,"finding":"Gephyrin, the main inhibitory receptor scaffold, is organized into sub-synaptic domains (SSDs) in vivo with distinct nanoscale arrangements depending on subcellular location and presynaptic partner. Chronic chemogenetic increases in cortical activity cause a reduction in gephyrin SSD volume specifically at axo-axonic (but not axo-dendritic) synapses, functionally weakening those contacts, demonstrating activity-dependent nanoscale remodeling of the inhibitory scaffold.","method":"dSTORM super-resolution microscopy in vivo, chemogenetic manipulation, electrophysiological measurement of synaptic strength","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — super-resolution imaging with functional electrophysiological validation and chemogenetic perturbation, preprint single lab","pmids":["bio_10.1101_2024.11.29.625981"],"is_preprint":true},{"year":2024,"finding":"An E3 ligase-dependent tool (paGFE3) that targets the RING domain of Mdm2 to gephyrin degrades gephyrin protein and ablates inhibitory synapses in response to 400 nm light, confirming that gephyrin is required for maintenance of inhibitory synaptic structure.","method":"Photoactivatable optogenetic degradation system (paGFE3), immunofluorescence of gephyrin levels and inhibitory synapse markers","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 3 / Weak — tool paper demonstrating gephyrin degradation ablates inhibitory synapses, single lab preprint, no deeper mechanistic dissection of gephyrin function","pmids":["bio_10.1101_2024.09.23.614589"],"is_preprint":true}],"current_model":"Gephyrin (GPHN) is a bifunctional scaffold protein: in neurons, it forms higher-order oligomers (dimers→tetramers→hexamers) whose structure is regulated by a flexible central linker harboring phosphorylation sites that control receptor-binding site accessibility; it clusters glycine and GABA-A receptors at inhibitory postsynaptic densities through its C-terminal E-domain, with collybistin and plasma-membrane phosphoinositides driving synaptic targeting and WNK1-dependent phosphorylation of the linker modulating receptor diffusion and stabilization; outside the nervous system, its MoeA-homology domain is essential for molybdenum insertion into the molybdenum cofactor, loss of which abolishes all cellular molybdoenzyme activities."},"narrative":{"mechanistic_narrative":"Gephyrin (GPHN) is a bifunctional protein that operates both as the principal scaffold organizing inhibitory postsynaptic densities and as an essential enzyme in molybdenum cofactor biosynthesis [PMID:11418245]. In its enzymatic role, gephyrin is required during molybdenum cofactor assembly for insertion of molybdenum into the cofactor, and loss-of-function mutations abrogate all molybdoenzyme activities [PMID:12754701, PMID:21031595]. In its scaffolding role, full-length gephyrin assembles hierarchically: a stable dimer forms the basic oligomeric unit that further builds into tetramers and hexamers, and a critical segment of its flexible central linker adopts alternative conformations, one of which occludes the receptor-binding site and which harbors key phosphorylation sites, coupling phosphorylation state to receptor binding [PMID:bio_10.1101_2025.09.01.673457]. Gephyrin clusters glycine and GABA-A receptors at the membrane through its C-terminal MoeA-homology E-domain, which is required for glycine receptor binding [PMID:12684523, PMID:bio_10.1101_2024.10.17.618879]. Synaptic targeting depends on collybistin, which drives gephyrin self-oligomerization into a high-molecular-weight complex stabilized by plasma-membrane phosphoinositides, while phosphorylation at Ser325 abolishes complex formation and impairs clustering [PMID:bio_10.1101_2025.01.20.633899]; a C-domain palmitoylation site (Cys212) is additionally required for correct synaptic targeting [PMID:bio_10.1101_2025.08.26.672322]. Receptor stability and diffusion are tuned by WNK1/SPAK-dependent phosphorylation of the central linker, which stabilizes GABA-A receptors at inhibitory synapses [PMID:bio_10.1101_2025.09.05.674425]. The scaffold is organized into activity-dependent sub-synaptic nanodomains whose remodeling controls synaptic strength [PMID:bio_10.1101_2024.11.29.625981], and gephyrin is required for maintenance of inhibitory synaptic structure [PMID:bio_10.1101_2024.09.23.614589]. Chromosomal translocation can fuse the gephyrin C-terminal half to MLL, generating an MLL-GPHN fusion in leukemia [PMID:11579461].","teleology":[{"year":2001,"claim":"Establishing gephyrin as a dual-function protein resolved whether one gene served both synaptic and metabolic roles, defining it as both a glycine-receptor anchor to subsynaptic microtubules and a molybdenum cofactor biosynthesis factor.","evidence":"Knockout mouse analysis with gene structure determination and localization studies","pmids":["11418245"],"confidence":"Medium","gaps":["Did not resolve the structural basis for either function","No molecular mechanism for how the same protein partitions between cytosolic enzymatic and synaptic scaffolding roles"]},{"year":2003,"claim":"Mapping the receptor-interaction determinant showed that glycine receptor binding requires an intact C-terminal MoeA-homology E-domain, localizing the scaffolding interface and showing that an N10Y mutation and splice variation do not disrupt clustering.","evidence":"Yeast two-hybrid, functional clustering assay, RT-PCR isoform analysis, and mutagenesis","pmids":["12684523"],"confidence":"Medium","gaps":["No structural detail of the E-domain/receptor interface","Affinity and stoichiometry of binding not defined"]},{"year":2003,"claim":"Patient mutation analysis confirmed gephyrin is indispensable specifically for the molybdenum insertion step of cofactor assembly, establishing the metabolic consequence of loss-of-function.","evidence":"Human mutation analysis combined with biochemical phenotyping of molybdoenzyme activities in patients","pmids":["12754701","21031595"],"confidence":"Medium","gaps":["No in vitro reconstitution of the molybdenum insertion reaction","Catalytic mechanism of metal insertion not defined"]},{"year":2001,"claim":"Characterization of a t(11;14) leukemia-associated MLL-GPHN fusion documented gephyrin involvement in oncogenic gene rearrangement and proposed a topoisomerase-II/NHEJ generation mechanism.","evidence":"cDNA library screening, fusion transcript identification, and genomic breakpoint analysis in a single patient","pmids":["11579461"],"confidence":"Medium","gaps":["No functional reconstitution of the fusion protein","Contribution of the gephyrin portion to leukemogenesis unknown"]},{"year":2024,"claim":"Reconstituting gephyrin-GlyR clusters in a heterologous system revealed that clustering itself modulates glycine affinity via the receptor beta-subunit N-terminus and that neuroligin-2 enlarges clusters, linking scaffold assembly to receptor function.","evidence":"Heterologous expression clustering assay, electrophysiology, and mutagenesis of the GlyR beta subunit (preprint)","pmids":["bio_10.1101_2024.10.17.618879"],"confidence":"Medium","gaps":["Performed in heterologous cells rather than native synapses","Stoichiometry of gephyrin within micron-sized clusters not defined"]},{"year":2024,"claim":"A zebrafish loss-of-function study extended gephyrin function beyond the postsynapse, implicating it in selective axon-class-dependent myelination by oligodendrocytes.","evidence":"Zebrafish gphnb loss-of-function genetics with imaging of myelin sheath length and distribution per axon class (preprint)","pmids":["bio_10.1101_2024.10.02.616365"],"confidence":"Medium","gaps":["No biochemical mechanism for the oligodendrocyte interaction identified","Relevance to mammalian myelination unknown"]},{"year":2024,"claim":"In vivo super-resolution imaging established that the inhibitory scaffold is organized into sub-synaptic domains that undergo activity-dependent nanoscale remodeling, functionally weakening axo-axonic contacts.","evidence":"dSTORM super-resolution microscopy in vivo, chemogenetic manipulation, and electrophysiological measurement of synaptic strength (preprint)","pmids":["bio_10.1101_2024.11.29.625981"],"confidence":"Medium","gaps":["Molecular trigger linking activity to SSD volume change unknown","Specificity for axo-axonic versus axo-dendritic synapses mechanistically unexplained"]},{"year":2024,"claim":"A light-controlled targeted degradation tool confirmed that gephyrin is causally required for maintenance of inhibitory synaptic structure.","evidence":"Photoactivatable optogenetic degradation (paGFE3) with immunofluorescence of gephyrin and synapse markers (preprint)","pmids":["bio_10.1101_2024.09.23.614589"],"confidence":"Low","gaps":["Tool demonstration without deeper mechanistic dissection","Does not distinguish acute structural roles from secondary effects of protein loss"]},{"year":2025,"claim":"Cryo-EM and reconstitution defined the hierarchical oligomerization of full-length gephyrin (dimer to tetramer to hexamer) and revealed a linker conformation that occludes the receptor-binding site, mechanistically coupling phosphorylation to receptor binding.","evidence":"Cryo-electron microscopy, biochemical reconstitution, and mutational analysis (preprint)","pmids":["bio_10.1101_2025.09.01.673457"],"confidence":"High","gaps":["Conformational switching not visualized in native synapses","Which kinases act on the linker sites in this structural context not established"]},{"year":2025,"claim":"Reconstitution of the gephyrin-collybistin complex showed collybistin drives gephyrin self-oligomerization into a >5 MDa assembly, with phosphoinositides promoting membrane targeting and Ser325 phosphorylation acting as a negative switch on complex formation.","evidence":"Biochemical reconstitution, Ser325 mutagenesis, phosphoinositide binding assays, and synaptic clustering assays (preprint)","pmids":["bio_10.1101_2025.01.20.633899"],"confidence":"High","gaps":["Kinase responsible for Ser325 phosphorylation in vivo not identified","Structure of the high-molecular-weight complex not resolved"]},{"year":2025,"claim":"Identification of WNK1/SPAK-dependent phosphorylation of two central-linker residues established a signaling pathway that tunes GABA-A receptor diffusion, clustering, and stability, with behavioral consequences in vivo.","evidence":"Phosphorylation site identification and mutagenesis, live imaging of receptor diffusion, electrophysiology, and in vivo anxiety behavior assay (preprint)","pmids":["bio_10.1101_2025.09.05.674425"],"confidence":"Medium","gaps":["Relationship between WNK sites and the Ser325/cryo-EM linker sites not integrated","Direct phosphorylation in vivo versus via SPAK not fully separated"]},{"year":2025,"claim":"A knock-in mouse of the C-domain microdeletion Delta199-233 showed that loss of the palmitoylation site (Cys212) is required for correct synaptic targeting and that targeting can be uncoupled from in vitro receptor affinity.","evidence":"Knock-in mouse, immunofluorescence of synaptic clustering, electrophysiology of inhibitory transmission, and PSD-95 cluster analysis (preprint)","pmids":["bio_10.1101_2025.08.26.672322"],"confidence":"Medium","gaps":["Direct demonstration that Cys212 palmitoylation alone drives targeting not isolated from the broader deletion","Mechanism of excitatory synapse compensation unknown"]},{"year":null,"claim":"How the cytosolic molybdenum-cofactor function and the synaptic scaffolding function are coordinated within a single protein, and how the multiple linker phosphorylation switches (WNK sites, Ser325) are integrated to control oligomerization and receptor binding in vivo, remain unresolved.","evidence":"No timeline discovery reconciles the enzymatic and scaffolding activities or unifies the distinct phosphoregulatory inputs","pmids":[],"confidence":"Low","gaps":["No integrated model of phosphorylation-state combinations","Spatial/temporal partitioning between metabolic and synaptic pools undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,2,4,7]},{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[1,2]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[2]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[4,7]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[2]},{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[2]}],"pathway":[],"complexes":["gephyrin-collybistin complex","inhibitory postsynaptic density"],"partners":["GLRB","COLLYBISTIN","NEUROLIGIN-2","WNK1","SPAK"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9NQX3","full_name":"Gephyrin","aliases":[],"length_aa":736,"mass_kda":79.7,"function":"Microtubule-associated protein involved in membrane protein-cytoskeleton interactions. It is thought to anchor the inhibitory glycine receptor (GLYR) to subsynaptic microtubules (By similarity). Acts as a major instructive molecule at inhibitory synapses, where it also clusters GABA type A receptors (PubMed:25025157, PubMed:26613940) Also has a catalytic activity and catalyzes two steps in the biosynthesis of the molybdenum cofactor. In the first step, molybdopterin is adenylated. Subsequently, molybdate is inserted into adenylated molybdopterin and AMP is released","subcellular_location":"Postsynaptic cell membrane; Cell membrane; Cytoplasm, cytosol; Cytoplasm, cytoskeleton; Cell projection, dendrite; Postsynaptic density","url":"https://www.uniprot.org/uniprotkb/Q9NQX3/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/GPHN","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"DYNLL1","stoichiometry":4.0},{"gene":"DYNLL2","stoichiometry":4.0},{"gene":"ACTG1","stoichiometry":0.2},{"gene":"AKT1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/GPHN","total_profiled":1310},"omim":[{"mim_id":"621348","title":"ZDHHC PALMITOYLTRANSFERASE 12; ZDHHC12","url":"https://www.omim.org/entry/621348"},{"mim_id":"617129","title":"INHIBITORY SYNAPTIC FACTOR 2A; INSYN2A","url":"https://www.omim.org/entry/617129"},{"mim_id":"617128","title":"INHIBITORY SYNAPTIC FACTOR 1; INSYN1","url":"https://www.omim.org/entry/617128"},{"mim_id":"615501","title":"MOLYBDENUM COFACTOR DEFICIENCY, TYPE C; MOCODC","url":"https://www.omim.org/entry/615501"},{"mim_id":"606479","title":"NEUROLIGIN 2; NLGN2","url":"https://www.omim.org/entry/606479"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Vesicles","reliability":"Approved"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"brain","ntpm":61.5},{"tissue":"liver","ntpm":58.3}],"url":"https://www.proteinatlas.org/search/GPHN"},"hgnc":{"alias_symbol":["KIAA1385","GEPH","GPH"],"prev_symbol":[]},"alphafold":{"accession":"Q9NQX3","domains":[{"cath_id":"3.40.980.10","chopping":"15-181","consensus_level":"high","plddt":92.4241,"start":15,"end":181},{"cath_id":"3.40.980.10","chopping":"318-338_498-646","consensus_level":"high","plddt":96.5292,"start":318,"end":646},{"cath_id":"3.90.105.10","chopping":"342-363_463-495","consensus_level":"medium","plddt":98.3138,"start":342,"end":495},{"cath_id":"2.170.190.11","chopping":"369-457","consensus_level":"medium","plddt":96.94,"start":369,"end":457},{"cath_id":"2.40.340.10","chopping":"655-731","consensus_level":"high","plddt":93.7251,"start":655,"end":731}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9NQX3","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9NQX3-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9NQX3-F1-predicted_aligned_error_v6.png","plddt_mean":83.81},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=GPHN","jax_strain_url":"https://www.jax.org/strain/search?query=GPHN"},"sequence":{"accession":"Q9NQX3","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9NQX3.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9NQX3/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9NQX3"}},"corpus_meta":[{"pmid":"23393157","id":"PMC_23393157","title":"Rare exonic deletions implicate the synaptic organizer Gephyrin (GPHN) in risk for autism, schizophrenia and seizures.","date":"2013","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/23393157","citation_count":121,"is_preprint":false},{"pmid":"21031595","id":"PMC_21031595","title":"Molybdenum cofactor deficiency: Mutations in GPHN, MOCS1, and MOCS2.","date":"2011","source":"Human mutation","url":"https://pubmed.ncbi.nlm.nih.gov/21031595","citation_count":106,"is_preprint":false},{"pmid":"12754701","id":"PMC_12754701","title":"Mutations in the molybdenum cofactor biosynthetic genes MOCS1, MOCS2, and GEPH.","date":"2003","source":"Human mutation","url":"https://pubmed.ncbi.nlm.nih.gov/12754701","citation_count":99,"is_preprint":false},{"pmid":"12684523","id":"PMC_12684523","title":"Isoform heterogeneity of the human gephyrin gene (GPHN), binding domains to the glycine receptor, and mutation analysis in hyperekplexia.","date":"2003","source":"The Journal of biological 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novel partner gene fused to MLL in a leukemia with t(11;14)(q23;q24).","date":"2001","source":"Genes, chromosomes & cancer","url":"https://pubmed.ncbi.nlm.nih.gov/11579461","citation_count":15,"is_preprint":false},{"pmid":"10572959","id":"PMC_10572959","title":"The gene for 2-phosphoglycolate phosphatase (gph) in Escherichia coli is located in the same operon as dam and at least five other diverse genes.","date":"1999","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/10572959","citation_count":12,"is_preprint":false},{"pmid":"30411419","id":"PMC_30411419","title":"The FRA14B common fragile site maps to a region prone to somatic and germline rearrangements within the large GPHN gene.","date":"2018","source":"Genes, chromosomes & cancer","url":"https://pubmed.ncbi.nlm.nih.gov/30411419","citation_count":5,"is_preprint":false},{"pmid":"40346986","id":"PMC_40346986","title":"LncRNA-GPHN Regulates Epilepsy by Inhibiting Apoptosis via the miR-320/YWHAH Axis in an Immature Rat Model of Status Epilepticus.","date":"2025","source":"Journal of cellular and molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/40346986","citation_count":1,"is_preprint":false},{"pmid":"40309610","id":"PMC_40309610","title":"Association and functional study of ATP6V1D and GPHN gene polymorphisms with depression in Chinese population.","date":"2025","source":"World journal of psychiatry","url":"https://pubmed.ncbi.nlm.nih.gov/40309610","citation_count":1,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2024.10.17.618879","title":"Modulation of heteromeric glycine receptor function through high concentration clustering","date":"2024-10-18","source":"bioRxiv","url":"https://doi.org/10.1101/2024.10.17.618879","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.10.02.616365","title":"Oligodendrocytes use postsynaptic proteins to coordinate myelin formation on axons of distinct neurotransmitter 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microdeletion","date":"2025-08-30","source":"bioRxiv","url":"https://doi.org/10.1101/2025.08.26.672322","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.09.05.674425","title":"WNK-Dependent Phosphorylation of Gephyrin Tunes GABA  <sub>A</sub>  Receptors at Inhibitory Synapses and Modulates Anxiety Behavior","date":"2025-09-05","source":"bioRxiv","url":"https://doi.org/10.1101/2025.09.05.674425","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.03.17.643750","title":"Next Generation of StayGold-based Adaptable Turn-On Maturation (ATOM) Sensors Targeting PSD95, Gephyrin, and HOMER1 Proteins","date":"2025-03-17","source":"bioRxiv","url":"https://doi.org/10.1101/2025.03.17.643750","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.01.20.633899","title":"Phosphoinositide- and Collybistin-Dependent Synaptic Clustering of Gephyrin","date":"2025-01-21","source":"bioRxiv","url":"https://doi.org/10.1101/2025.01.20.633899","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.09.23.614589","title":"A toolbox for ablating excitatory and inhibitory synapses","date":"2024-09-24","source":"bioRxiv","url":"https://doi.org/10.1101/2024.09.23.614589","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.07.23.604723","title":"Evolutionary plasticity and functional repurposing of the essential metabolic enzyme MoeA","date":"2024-07-23","source":"bioRxiv","url":"https://doi.org/10.1101/2024.07.23.604723","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.11.29.625981","title":"In vivo modulation of network activity drives the nanoscale reorganisation of axo-axonic synapses at the axon initial segment","date":"2024-11-30","source":"bioRxiv","url":"https://doi.org/10.1101/2024.11.29.625981","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":13119,"output_tokens":3243,"usd":0.044001,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":10799,"output_tokens":4313,"usd":0.08091,"stage2_stop_reason":"end_turn"},"total_usd":0.124911,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2003,\n      \"finding\": \"GlyR-gephyrin binding is dependent on the presence of an intact C-terminal MoeA homology (E-domain) of gephyrin. The N10Y missense mutation and alternative splicing of GPHN transcripts do not disrupt GlyR-gephyrin interactions or collybistin-induced cell-surface clustering.\",\n      \"method\": \"Yeast two-hybrid, functional clustering assay, RT-PCR isoform analysis, mutagenesis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — yeast two-hybrid plus functional clustering assay with mutagenesis, single lab\",\n      \"pmids\": [\"12684523\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Gephyrin (encoded by GEPH/GPHN) is required during molybdenum cofactor assembly for insertion of molybdenum into the cofactor; loss-of-function mutations abrogate all molybdoenzyme activities.\",\n      \"method\": \"Human mutation analysis combined with biochemical phenotyping of molybdoenzyme activities in patients\",\n      \"journal\": \"Human mutation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Strong — replicated across multiple patient families and two review papers drawing on biochemical phenotyping, but primarily genetic/biochemical phenotype rather than in vitro reconstitution\",\n      \"pmids\": [\"12754701\", \"21031595\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Gephyrin functions as a peripheral membrane scaffolding protein anchoring glycine receptors to subsynaptic microtubules; it also plays a role in GABA-A receptor localization at the synapse and in molybdenum cofactor biosynthesis, as established by knockout mouse phenotypes.\",\n      \"method\": \"Knockout mouse analysis, gene structure determination, localization studies\",\n      \"journal\": \"Gene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — knockout mouse model with defined dual phenotypes (receptor clustering loss + MoCo deficiency), single study\",\n      \"pmids\": [\"11418245\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"In a translocation t(11;14)(q23;q24)-associated leukemia, the GPHN C-terminal half (including a tubulin-binding site and MoeA homology domain) is fused to MLL AT-hook and DNA methyltransferase homology domains, generating an MLL-GPHN fusion protein. Genomic breakpoint analysis identified topoisomerase-II DNA-binding sites spanning both breakpoints, suggesting VP16/topoisomerase-II-induced double-strand breaks and non-homologous end joining as the generation mechanism.\",\n      \"method\": \"cDNA library screening, fusion transcript identification, genomic breakpoint analysis\",\n      \"journal\": \"Genes, chromosomes & cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — direct molecular characterization of fusion gene in a single patient, no functional reconstitution of the fusion protein\",\n      \"pmids\": [\"11579461\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Gephyrin assembles with heteromeric α2β glycine receptors (GlyRs) into micron-sized clusters at the plasma membrane. Neuroligin-2 further increases cluster sizes and GlyR concentration. A positively charged N-terminus sequence of the GlyR β subunit is essential for glycine affinity modulation through clustering. Ligand re-binding to adjacent clustered GlyRs alters kinetics but not chemical equilibrium.\",\n      \"method\": \"Heterologous expression clustering assay, electrophysiology, mutagenesis of GlyR β subunit N-terminus\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional reconstitution in heterologous system with mutagenesis and electrophysiology, preprint single lab\",\n      \"pmids\": [\"bio_10.1101_2024.10.17.618879\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"In zebrafish, Gephyrin (Gphnb) is enriched in myelin on GABAergic and glycinergic axons. Loss of gphnb causes longer myelin sheaths specifically on GABAergic axons and shifts myelin placement toward glutamatergic axons at the expense of GABAergic axons, indicating gephyrin mediates selective axon-class-dependent myelination by oligodendrocytes.\",\n      \"method\": \"Zebrafish gphnb loss-of-function genetics, imaging of myelin sheath length and distribution per axon class\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — clean genetic KO in zebrafish with specific cellular phenotype, preprint single lab, no biochemical mechanism for oligodendrocyte interaction identified\",\n      \"pmids\": [\"bio_10.1101_2024.10.02.616365\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Cryo-EM combined with biochemical reconstitution and mutational analyses shows that full-length gephyrin forms a stable dimer as the basic oligomeric unit, which further assembles into linear and oblique tetramers and linear hexamers. A critical segment of the flexible central linker adopts two distinct conformations, one of which occludes the receptor-binding site, and this segment harbors key phosphorylation sites, providing a mechanistic link between phosphorylation state, linker conformation, and receptor binding.\",\n      \"method\": \"Cryo-electron microscopy, biochemical reconstitution, mutational analysis\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — cryo-EM structure with reconstitution and mutagenesis in a single rigorous study; preprint but multiple orthogonal methods\",\n      \"pmids\": [\"bio_10.1101_2025.09.01.673457\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Collybistin induces gephyrin self-oligomerization into a high-molecular-weight (>5 MDa) gephyrin-collybistin complex at GABAergic synapses. Plasma-membrane phosphoinositides promote complex formation and are critical for membrane targeting and stabilization. Gephyrin phosphorylation at Ser325 abolishes complex formation with collybistin, impairing collybistin-dependent gephyrin clustering at GABAergic synapses.\",\n      \"method\": \"Biochemical reconstitution of gephyrin-collybistin complex, phosphorylation site mutagenesis (Ser325), phosphoinositide binding assays, synaptic clustering assays\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution of complex with mutagenesis and lipid binding assays, multiple orthogonal methods in single preprint study\",\n      \"pmids\": [\"bio_10.1101_2025.01.20.633899\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"WNK1 kinase (and its effector SPAK) directly phosphorylates two previously uncharacterized residues in the central linker region of gephyrin. This phosphorylation controls GABA-A receptor synaptic diffusion, clustering, membrane stability, and endocytosis at inhibitory synapses. Activation of WNK signaling stabilizes GABA-A Rs at inhibitory synapses; inhibition enhances receptor internalization. Expression of a phospho-mimetic form of gephyrin at WNK-targeted sites produces anxiolytic effects in vivo.\",\n      \"method\": \"Phosphorylation site identification and mutagenesis, live imaging of receptor diffusion, electrophysiology of GABAergic currents, in vivo behavioral assay (anxiety)\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — phospho-mimetic/phospho-null mutagenesis combined with receptor trafficking assays and in vivo behavior, preprint single lab\",\n      \"pmids\": [\"bio_10.1101_2025.09.05.674425\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"A knock-in mouse model of the gephyrin microdeletion Δ199-233 (within the C-domain, removing a region that includes the S-palmitoylation site at Cys212) disrupts synaptic targeting of gephyrin in dissociated hippocampal neurons. Despite unexpectedly facilitating receptor interaction in vitro, inhibitory signal transmission is reduced. Compensatory changes occur at excitatory synapses (smaller but more numerous PSD-95 clusters). Loss of the C-domain palmitoylation site is required for correct synaptic targeting.\",\n      \"method\": \"Knock-in mouse model, immunofluorescence of synaptic clustering in hippocampal neurons, electrophysiology of inhibitory transmission, PSD-95 cluster analysis\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo knock-in model with cellular and electrophysiological readouts, multiple phenotypic analyses; preprint single lab\",\n      \"pmids\": [\"bio_10.1101_2025.08.26.672322\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Gephyrin, the main inhibitory receptor scaffold, is organized into sub-synaptic domains (SSDs) in vivo with distinct nanoscale arrangements depending on subcellular location and presynaptic partner. Chronic chemogenetic increases in cortical activity cause a reduction in gephyrin SSD volume specifically at axo-axonic (but not axo-dendritic) synapses, functionally weakening those contacts, demonstrating activity-dependent nanoscale remodeling of the inhibitory scaffold.\",\n      \"method\": \"dSTORM super-resolution microscopy in vivo, chemogenetic manipulation, electrophysiological measurement of synaptic strength\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — super-resolution imaging with functional electrophysiological validation and chemogenetic perturbation, preprint single lab\",\n      \"pmids\": [\"bio_10.1101_2024.11.29.625981\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"An E3 ligase-dependent tool (paGFE3) that targets the RING domain of Mdm2 to gephyrin degrades gephyrin protein and ablates inhibitory synapses in response to 400 nm light, confirming that gephyrin is required for maintenance of inhibitory synaptic structure.\",\n      \"method\": \"Photoactivatable optogenetic degradation system (paGFE3), immunofluorescence of gephyrin levels and inhibitory synapse markers\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — tool paper demonstrating gephyrin degradation ablates inhibitory synapses, single lab preprint, no deeper mechanistic dissection of gephyrin function\",\n      \"pmids\": [\"bio_10.1101_2024.09.23.614589\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"Gephyrin (GPHN) is a bifunctional scaffold protein: in neurons, it forms higher-order oligomers (dimers→tetramers→hexamers) whose structure is regulated by a flexible central linker harboring phosphorylation sites that control receptor-binding site accessibility; it clusters glycine and GABA-A receptors at inhibitory postsynaptic densities through its C-terminal E-domain, with collybistin and plasma-membrane phosphoinositides driving synaptic targeting and WNK1-dependent phosphorylation of the linker modulating receptor diffusion and stabilization; outside the nervous system, its MoeA-homology domain is essential for molybdenum insertion into the molybdenum cofactor, loss of which abolishes all cellular molybdoenzyme activities.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"Gephyrin (GPHN) is a bifunctional protein that operates both as the principal scaffold organizing inhibitory postsynaptic densities and as an essential enzyme in molybdenum cofactor biosynthesis [#2]. In its enzymatic role, gephyrin is required during molybdenum cofactor assembly for insertion of molybdenum into the cofactor, and loss-of-function mutations abrogate all molybdoenzyme activities [#1]. In its scaffolding role, full-length gephyrin assembles hierarchically: a stable dimer forms the basic oligomeric unit that further builds into tetramers and hexamers, and a critical segment of its flexible central linker adopts alternative conformations, one of which occludes the receptor-binding site and which harbors key phosphorylation sites, coupling phosphorylation state to receptor binding [#6]. Gephyrin clusters glycine and GABA-A receptors at the membrane through its C-terminal MoeA-homology E-domain, which is required for glycine receptor binding [#0, #4]. Synaptic targeting depends on collybistin, which drives gephyrin self-oligomerization into a high-molecular-weight complex stabilized by plasma-membrane phosphoinositides, while phosphorylation at Ser325 abolishes complex formation and impairs clustering [#7]; a C-domain palmitoylation site (Cys212) is additionally required for correct synaptic targeting [#9]. Receptor stability and diffusion are tuned by WNK1/SPAK-dependent phosphorylation of the central linker, which stabilizes GABA-A receptors at inhibitory synapses [#8]. The scaffold is organized into activity-dependent sub-synaptic nanodomains whose remodeling controls synaptic strength [#10], and gephyrin is required for maintenance of inhibitory synaptic structure [#11]. Chromosomal translocation can fuse the gephyrin C-terminal half to MLL, generating an MLL-GPHN fusion in leukemia [#3].\",\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"Establishing gephyrin as a dual-function protein resolved whether one gene served both synaptic and metabolic roles, defining it as both a glycine-receptor anchor to subsynaptic microtubules and a molybdenum cofactor biosynthesis factor.\",\n      \"evidence\": \"Knockout mouse analysis with gene structure determination and localization studies\",\n      \"pmids\": [\"11418245\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not resolve the structural basis for either function\", \"No molecular mechanism for how the same protein partitions between cytosolic enzymatic and synaptic scaffolding roles\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Mapping the receptor-interaction determinant showed that glycine receptor binding requires an intact C-terminal MoeA-homology E-domain, localizing the scaffolding interface and showing that an N10Y mutation and splice variation do not disrupt clustering.\",\n      \"evidence\": \"Yeast two-hybrid, functional clustering assay, RT-PCR isoform analysis, and mutagenesis\",\n      \"pmids\": [\"12684523\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural detail of the E-domain/receptor interface\", \"Affinity and stoichiometry of binding not defined\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Patient mutation analysis confirmed gephyrin is indispensable specifically for the molybdenum insertion step of cofactor assembly, establishing the metabolic consequence of loss-of-function.\",\n      \"evidence\": \"Human mutation analysis combined with biochemical phenotyping of molybdoenzyme activities in patients\",\n      \"pmids\": [\"12754701\", \"21031595\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No in vitro reconstitution of the molybdenum insertion reaction\", \"Catalytic mechanism of metal insertion not defined\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Characterization of a t(11;14) leukemia-associated MLL-GPHN fusion documented gephyrin involvement in oncogenic gene rearrangement and proposed a topoisomerase-II/NHEJ generation mechanism.\",\n      \"evidence\": \"cDNA library screening, fusion transcript identification, and genomic breakpoint analysis in a single patient\",\n      \"pmids\": [\"11579461\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No functional reconstitution of the fusion protein\", \"Contribution of the gephyrin portion to leukemogenesis unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Reconstituting gephyrin-GlyR clusters in a heterologous system revealed that clustering itself modulates glycine affinity via the receptor beta-subunit N-terminus and that neuroligin-2 enlarges clusters, linking scaffold assembly to receptor function.\",\n      \"evidence\": \"Heterologous expression clustering assay, electrophysiology, and mutagenesis of the GlyR beta subunit (preprint)\",\n      \"pmids\": [\"bio_10.1101_2024.10.17.618879\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Performed in heterologous cells rather than native synapses\", \"Stoichiometry of gephyrin within micron-sized clusters not defined\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"A zebrafish loss-of-function study extended gephyrin function beyond the postsynapse, implicating it in selective axon-class-dependent myelination by oligodendrocytes.\",\n      \"evidence\": \"Zebrafish gphnb loss-of-function genetics with imaging of myelin sheath length and distribution per axon class (preprint)\",\n      \"pmids\": [\"bio_10.1101_2024.10.02.616365\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No biochemical mechanism for the oligodendrocyte interaction identified\", \"Relevance to mammalian myelination unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"In vivo super-resolution imaging established that the inhibitory scaffold is organized into sub-synaptic domains that undergo activity-dependent nanoscale remodeling, functionally weakening axo-axonic contacts.\",\n      \"evidence\": \"dSTORM super-resolution microscopy in vivo, chemogenetic manipulation, and electrophysiological measurement of synaptic strength (preprint)\",\n      \"pmids\": [\"bio_10.1101_2024.11.29.625981\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular trigger linking activity to SSD volume change unknown\", \"Specificity for axo-axonic versus axo-dendritic synapses mechanistically unexplained\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"A light-controlled targeted degradation tool confirmed that gephyrin is causally required for maintenance of inhibitory synaptic structure.\",\n      \"evidence\": \"Photoactivatable optogenetic degradation (paGFE3) with immunofluorescence of gephyrin and synapse markers (preprint)\",\n      \"pmids\": [\"bio_10.1101_2024.09.23.614589\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Tool demonstration without deeper mechanistic dissection\", \"Does not distinguish acute structural roles from secondary effects of protein loss\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Cryo-EM and reconstitution defined the hierarchical oligomerization of full-length gephyrin (dimer to tetramer to hexamer) and revealed a linker conformation that occludes the receptor-binding site, mechanistically coupling phosphorylation to receptor binding.\",\n      \"evidence\": \"Cryo-electron microscopy, biochemical reconstitution, and mutational analysis (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.09.01.673457\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Conformational switching not visualized in native synapses\", \"Which kinases act on the linker sites in this structural context not established\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Reconstitution of the gephyrin-collybistin complex showed collybistin drives gephyrin self-oligomerization into a >5 MDa assembly, with phosphoinositides promoting membrane targeting and Ser325 phosphorylation acting as a negative switch on complex formation.\",\n      \"evidence\": \"Biochemical reconstitution, Ser325 mutagenesis, phosphoinositide binding assays, and synaptic clustering assays (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.01.20.633899\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Kinase responsible for Ser325 phosphorylation in vivo not identified\", \"Structure of the high-molecular-weight complex not resolved\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identification of WNK1/SPAK-dependent phosphorylation of two central-linker residues established a signaling pathway that tunes GABA-A receptor diffusion, clustering, and stability, with behavioral consequences in vivo.\",\n      \"evidence\": \"Phosphorylation site identification and mutagenesis, live imaging of receptor diffusion, electrophysiology, and in vivo anxiety behavior assay (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.09.05.674425\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Relationship between WNK sites and the Ser325/cryo-EM linker sites not integrated\", \"Direct phosphorylation in vivo versus via SPAK not fully separated\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"A knock-in mouse of the C-domain microdeletion Delta199-233 showed that loss of the palmitoylation site (Cys212) is required for correct synaptic targeting and that targeting can be uncoupled from in vitro receptor affinity.\",\n      \"evidence\": \"Knock-in mouse, immunofluorescence of synaptic clustering, electrophysiology of inhibitory transmission, and PSD-95 cluster analysis (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.08.26.672322\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct demonstration that Cys212 palmitoylation alone drives targeting not isolated from the broader deletion\", \"Mechanism of excitatory synapse compensation unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the cytosolic molybdenum-cofactor function and the synaptic scaffolding function are coordinated within a single protein, and how the multiple linker phosphorylation switches (WNK sites, Ser325) are integrated to control oligomerization and receptor binding in vivo, remain unresolved.\",\n      \"evidence\": \"No timeline discovery reconciles the enzymatic and scaffolding activities or unifies the distinct phosphoregulatory inputs\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No integrated model of phosphorylation-state combinations\", \"Spatial/temporal partitioning between metabolic and synaptic pools undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 2, 4, 7]},\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [1, 2]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [4, 7]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0112316\", \"supporting_discovery_ids\": []}\n    ],\n    \"complexes\": [\n      \"gephyrin-collybistin complex\",\n      \"inhibitory postsynaptic density\"\n    ],\n    \"partners\": [\n      \"GLRB\",\n      \"collybistin\",\n      \"neuroligin-2\",\n      \"WNK1\",\n      \"SPAK\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":4,"faith_pct":100.0}}