{"gene":"ELMOD1","run_date":"2026-06-09T23:54:43","timeline":{"discoveries":[{"year":2007,"finding":"ELMOD1 was found to have ARL2 GTPase-activating protein (GAP) activity, similar to its paralog ELMOD2 purified from bovine testis.","method":"In vitro GAP activity assay on purified/recombinant protein","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct biochemical assay of GAP activity, foundational finding replicated in subsequent studies","pmids":["17452337"],"is_preprint":false},{"year":2012,"finding":"The ELMO domain of ELMOD1 contains a highly conserved arginine residue critical for GAP activity toward ARF family GTPases; mutagenesis of this residue abolished both biochemical and cellular GAP activity. ELMOD1 was also shown to act as an ARF family GAP at the Golgi.","method":"Unbiased phylogenetic analysis, sequence alignments, three independent biochemical/cellular GAP assays, active-site mutagenesis, subcellular localization (Golgi)","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — active-site mutagenesis combined with three orthogonal GAP assays and cellular localization in a single rigorous study","pmids":["23014990"],"is_preprint":false},{"year":2012,"finding":"Loss-of-function mutations in mouse Elmod1 (rda and rda2J alleles) cause cochlear hair cell dysfunction characterized by elongation and fusion of inner hair cell stereocilia and progressive degeneration of outer hair cell stereocilia, linking ELMOD1-mediated GTPase signaling to actin cytoskeleton dynamics in stereocilia.","method":"Positional cloning of naturally occurring mouse mutations, histology/morphological analysis of hair cell stereocilia","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean loss-of-function genetic model with specific cellular phenotype, but mechanism inferred rather than directly demonstrated in this paper","pmids":["22558334"],"is_preprint":false},{"year":2014,"finding":"Recombinant ELMOD1 displays GAP activity with distinct specificities toward multiple ARF family GTPases. The non-opioid sigma-1 receptor (S1R) was identified as a novel effector that directly binds ELMOD1 and inhibits its GAP activity.","method":"Overexpression in HEK293T cells, purification, in vitro GAP activity assays, direct binding assay (S1R binding to ELMOD1 inhibiting GAP activity)","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstituted GAP assays with purified proteins plus direct binding inhibition assay, single lab but multiple orthogonal methods","pmids":["24616099"],"is_preprint":false},{"year":2017,"finding":"ELMOD1 acts as a GAP for ARF6 in vestibular hair cells; loss of ELMOD1 in rda/rda mice leads to elevated ARF6-GTP/GDP ratio, invasion of vesicles into the cuticular plate, apical membrane lifting, and stereocilia elongation/fusion. ARF6-GTP levels correlated with phenotype severity, indicating ELMOD1-mediated ARF6-GDP conversion stabilizes apical hair cell structures.","method":"Analysis of rda/rda knockout mice, FM1-43 membrane trafficking assay, ARF6 GTP/GDP ratio measurement by biochemical assay, correlation of ARF6-GTP levels with phenotype severity","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean genetic loss-of-function model with direct measurement of ARF6 GTP/GDP ratio as mechanistic readout, multiple orthogonal methods","pmids":["29222402"],"is_preprint":false},{"year":2021,"finding":"ELMOD1 (and ELMOD3) localizes to the Golgi and cilia, and its deletion impairs primary cilia formation, causes loss of a subset of ciliary proteins from cilia, and leads to accumulation of ciliary proteins at the Golgi, consistent with compromised Golgi-to-cilia trafficking. These phenotypes are rescued by activating mutant expression of ARL3 or ARL16, placing ELMOD1 upstream of these ARF-family GTPases in the ciliogenesis pathway.","method":"Elmod1 knockout mouse embryonic fibroblasts, ciliogenesis assays, immunofluorescence localization, genetic epistasis with ARL3/ARL16 activating mutants","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean KO model with defined phenotype, genetic epistasis with activating mutants, direct localization, replicated across two paralogs","pmids":["34818063"],"is_preprint":false},{"year":2021,"finding":"ELMOD1 mediates the surface presentation of the G protein-coupled receptor APLNR at the plasma membrane of glioblastoma stem-like cells downstream of the glycoprotein GP130, potentially via ARF-mediated endovesicular trafficking.","method":"Co-immunoprecipitation, surface receptor presentation assays in GSCs, functional self-renewal assays with GP130 interference","journal":"The Journal of cell biology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, ELMOD1's role is inferred from GP130-APLNR interaction context with limited direct mechanistic evidence for ELMOD1 specifically","pmids":["34287648"],"is_preprint":false},{"year":2023,"finding":"The C. elegans ELMOD ortholog ELMD-1, together with WDR31 and RP-2, regulates IFT complex assembly at the ciliary base and BBSome entry/exit from cilia; triple loss-of-function causes accumulation of IFT Complex B components and KIF17 in cilia and increased anterograde IFT speed, and allows a non-ciliary protein to leak into cilia.","method":"C. elegans and zebrafish genetics, IFT particle tracking by live imaging, genetic epistasis (triple mutant wdr-31;rpi-2;elmd-1)","journal":"Life science alliance","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean genetic model in C. elegans with live IFT imaging, but contribution of ELMD-1 specifically is assessed in a triple mutant context making individual contributions harder to isolate","pmids":["37208194"],"is_preprint":false}],"current_model":"ELMOD1 is an ELMO domain-containing GTPase-activating protein (GAP) with activity toward ARF family GTPases (including ARF6, ARL2, and others), operating at the Golgi and in cilia to regulate Golgi-to-cilia protein trafficking, ciliogenesis, and stabilization of apical actin/membrane structures in sensory hair cells via conversion of ARF6 to its GDP-bound form; its GAP activity is inhibited by direct binding of the sigma-1 receptor, and it functions upstream of ARL3/ARL16 in the ciliogenesis pathway."},"narrative":{"mechanistic_narrative":"ELMOD1 is an ELMO domain-containing GTPase-activating protein (GAP) that regulates ARF-family GTPase signaling at the Golgi and cilia, governing membrane trafficking, ciliogenesis, and apical actin/membrane organization [PMID:23014990, PMID:34818063]. Its GAP activity was first established biochemically toward ARL2 [PMID:17452337] and extended to multiple ARF-family GTPases, with a single conserved arginine residue in the ELMO domain being essential for catalysis at the Golgi [PMID:23014990]. In sensory hair cells ELMOD1 converts ARF6 to its GDP-bound state, and its loss elevates the ARF6-GTP/GDP ratio, causing vesicle invasion into the cuticular plate, apical membrane lifting, and stereocilia elongation and fusion [PMID:22558334, PMID:29222402]. ELMOD1 also acts upstream of ARL3 and ARL16 in ciliogenesis, where its deletion impairs primary cilium formation and Golgi-to-cilia trafficking, phenotypes rescued by activating ARL3 or ARL16 mutants [PMID:34818063]. The sigma-1 receptor binds ELMOD1 directly and inhibits its GAP activity, defining a regulatory effector input [PMID:24616099].","teleology":[{"year":2007,"claim":"Establishing whether ELMOD1 has intrinsic enzymatic activity, the first study showed it functions as a GAP toward ARL2, defining its core biochemical role.","evidence":"In vitro GAP activity assay on purified protein from bovine testis","pmids":["17452337"],"confidence":"High","gaps":["Specificity beyond ARL2 not addressed","Catalytic residues not yet mapped","No cellular context established"]},{"year":2012,"claim":"To determine how ELMOD1 catalyzes GTP hydrolysis and where it acts, mutagenesis identified a conserved arginine essential for GAP activity toward ARF-family GTPases and localized activity to the Golgi.","evidence":"Phylogenetic analysis, three orthogonal GAP assays, active-site mutagenesis, subcellular localization","pmids":["23014990"],"confidence":"High","gaps":["Full set of physiological GTPase substrates not defined","Recruitment mechanism to Golgi unknown"]},{"year":2012,"claim":"Linking ELMOD1 to organismal phenotype, loss-of-function mouse alleles tied the gene to hair cell stereocilia integrity, implicating GTPase signaling in actin cytoskeleton dynamics.","evidence":"Positional cloning of mouse rda/rda2J alleles, stereocilia histology","pmids":["22558334"],"confidence":"Medium","gaps":["Mechanism inferred, not demonstrated in this study","Which GTPase mediates the actin phenotype not identified"]},{"year":2014,"claim":"Addressing how ELMOD1 GAP activity is regulated, the sigma-1 receptor was identified as a direct binding effector that inhibits ELMOD1 GAP activity, and the enzyme's distinct specificities across ARF-family GTPases were resolved.","evidence":"Recombinant protein purification, in vitro GAP assays, direct binding inhibition assay","pmids":["24616099"],"confidence":"High","gaps":["Physiological relevance of S1R inhibition in tissues untested","Stoichiometry and binding interface not defined"]},{"year":2017,"claim":"Connecting biochemistry to the hair cell phenotype, ELMOD1 was shown to act as an ARF6 GAP whose loss elevates ARF6-GTP and destabilizes apical membrane/actin structures, providing a direct mechanistic readout.","evidence":"rda/rda knockout mice, FM1-43 trafficking assay, ARF6 GTP/GDP ratio measurement correlated with phenotype severity","pmids":["29222402"],"confidence":"High","gaps":["How ARF6-GDP conversion stabilizes apical structures mechanistically unresolved","Effectors downstream of ARF6 not identified"]},{"year":2021,"claim":"Placing ELMOD1 in the ciliogenesis pathway, deletion impaired cilium formation and Golgi-to-cilia trafficking, with rescue by activating ARL3/ARL16 mutants establishing ELMOD1 upstream of these GTPases.","evidence":"Elmod1 knockout MEFs, ciliogenesis assays, immunofluorescence, genetic epistasis with ARL3/ARL16 activating mutants","pmids":["34818063"],"confidence":"High","gaps":["Direct GAP action on ARL3/ARL16 versus pathway position not biochemically distinguished","Identity of mislocalized ciliary cargo subset incomplete"]},{"year":2021,"claim":"Exploring a disease context, ELMOD1 was linked to surface presentation of the GPCR APLNR in glioblastoma stem-like cells downstream of GP130, suggesting a role in receptor trafficking.","evidence":"Co-immunoprecipitation, surface receptor assays, self-renewal functional assays in GSCs","pmids":["34287648"],"confidence":"Low","gaps":["ELMOD1 role inferred from GP130-APLNR context with limited direct mechanistic evidence","ARF-dependence of the trafficking not demonstrated","Single lab, no reciprocal validation"]},{"year":2023,"claim":"Extending ciliary function across species, the C. elegans ortholog ELMD-1 was shown to regulate IFT complex assembly and BBSome ciliary entry/exit, with triple mutants disrupting IFT speed and ciliary protein gating.","evidence":"C. elegans and zebrafish genetics, live IFT particle tracking, triple-mutant epistasis","pmids":["37208194"],"confidence":"Medium","gaps":["Individual ELMD-1 contribution obscured by triple-mutant analysis","Conservation of this IFT role in mammalian ELMOD1 untested"]},{"year":null,"claim":"How ELMOD1 GAP activity toward distinct ARF-family GTPases is spatially partitioned between Golgi, cilia, and the hair cell apex, and how a single GAP coordinates these distinct trafficking outputs, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of ELMOD1 bound to substrate GTPases","Recruitment/targeting determinants across compartments unknown","Direct versus indirect relationship to ARL3/ARL16 not biochemically settled"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1,3,4]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[1,4]}],"localization":[{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[1,5]},{"term_id":"GO:0005929","term_label":"cilium","supporting_discovery_ids":[5]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[4,5]},{"term_id":"R-HSA-1852241","term_label":"Organelle biogenesis and maintenance","supporting_discovery_ids":[5]}],"complexes":[],"partners":["ARF6","ARL2","ARL3","ARL16","SIGMAR1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8N336","full_name":"ELMO domain-containing protein 1","aliases":[],"length_aa":334,"mass_kda":39.1,"function":"Acts as a GTPase-activating protein (GAP) toward guanine nucleotide exchange factors like ARL2, ARL3, ARF1 and ARF6, but not for GTPases outside the Arf family","subcellular_location":"","url":"https://www.uniprot.org/uniprotkb/Q8N336/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ELMOD1","classification":"Not Classified","n_dependent_lines":9,"n_total_lines":1208,"dependency_fraction":0.0074503311258278145},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/ELMOD1","total_profiled":1310},"omim":[{"mim_id":"615456","title":"ELMO/CED12 DOMAIN-CONTAINING PROTEIN 1; ELMOD1","url":"https://www.omim.org/entry/615456"},{"mim_id":"615427","title":"ELMO/CED12 DOMAIN-CONTAINING PROTEIN 3; ELMOD3","url":"https://www.omim.org/entry/615427"},{"mim_id":"601175","title":"ADP-RIBOSYLATION FACTOR-LIKE GTPase 2; ARL2","url":"https://www.omim.org/entry/601175"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Vesicles","reliability":"Additional"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Group enriched","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"brain","ntpm":51.8},{"tissue":"pituitary gland","ntpm":20.0},{"tissue":"retina","ntpm":30.2},{"tissue":"skin 1","ntpm":27.3}],"url":"https://www.proteinatlas.org/search/ELMOD1"},"hgnc":{"alias_symbol":["DKFZp547C176"],"prev_symbol":[]},"alphafold":{"accession":"Q8N336","domains":[{"cath_id":"-","chopping":"35-124","consensus_level":"high","plddt":95.1494,"start":35,"end":124},{"cath_id":"-","chopping":"129-334","consensus_level":"high","plddt":90.5897,"start":129,"end":334},{"cath_id":"1.20.5","chopping":"2-28","consensus_level":"medium","plddt":86.7519,"start":2,"end":28}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8N336","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8N336-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8N336-F1-predicted_aligned_error_v6.png","plddt_mean":90.75},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ELMOD1","jax_strain_url":"https://www.jax.org/strain/search?query=ELMOD1"},"sequence":{"accession":"Q8N336","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8N336.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8N336/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8N336"}},"corpus_meta":[{"pmid":"24523945","id":"PMC_24523945","title":"Functionally enigmatic genes: a case study of the brain ignorome.","date":"2014","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/24523945","citation_count":78,"is_preprint":false},{"pmid":"17452337","id":"PMC_17452337","title":"ELMOD2 is an Arl2 GTPase-activating protein that also acts on Arfs.","date":"2007","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17452337","citation_count":74,"is_preprint":false},{"pmid":"23014990","id":"PMC_23014990","title":"ELMO domains, evolutionary and functional characterization of a novel GTPase-activating protein (GAP) domain for Arf protein family GTPases.","date":"2012","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/23014990","citation_count":56,"is_preprint":false},{"pmid":"24616099","id":"PMC_24616099","title":"Characterization of recombinant ELMOD (cell engulfment and motility domain) proteins as GTPase-activating proteins (GAPs) for ARF family GTPases.","date":"2014","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/24616099","citation_count":47,"is_preprint":false},{"pmid":"22558334","id":"PMC_22558334","title":"Mutations of the mouse ELMO domain containing 1 gene (Elmod1) link small GTPase signaling to actin cytoskeleton dynamics in hair cell stereocilia.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/22558334","citation_count":32,"is_preprint":false},{"pmid":"33893326","id":"PMC_33893326","title":"Elevated expression of the adhesion GPCR ADGRL4/ELTD1 promotes endothelial sprouting angiogenesis without activating canonical GPCR signalling.","date":"2021","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/33893326","citation_count":28,"is_preprint":false},{"pmid":"35065650","id":"PMC_35065650","title":"Genome-wide analysis of cell-Free DNA methylation profiling with MeDIP-seq identified potential biomarkers for colorectal cancer.","date":"2022","source":"World journal of surgical oncology","url":"https://pubmed.ncbi.nlm.nih.gov/35065650","citation_count":16,"is_preprint":false},{"pmid":"32814070","id":"PMC_32814070","title":"The Rac2 GTPase contributes to cathepsin H-mediated protection against cytokine-induced apoptosis in insulin-secreting cells.","date":"2020","source":"Molecular and cellular endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/32814070","citation_count":16,"is_preprint":false},{"pmid":"29222402","id":"PMC_29222402","title":"ELMOD1 Stimulates ARF6-GTP Hydrolysis to Stabilize Apical Structures in Developing Vestibular Hair Cells.","date":"2017","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/29222402","citation_count":12,"is_preprint":false},{"pmid":"34818063","id":"PMC_34818063","title":"The ARF GAPs ELMOD1 and ELMOD3 act at the Golgi and cilia to regulate ciliogenesis and ciliary protein traffic.","date":"2021","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/34818063","citation_count":11,"is_preprint":false},{"pmid":"39725721","id":"PMC_39725721","title":"High-resolution DNA methylation changes reveal biomarkers of heart failure with preserved ejection fraction versus reduced ejection fraction.","date":"2024","source":"Basic research in cardiology","url":"https://pubmed.ncbi.nlm.nih.gov/39725721","citation_count":10,"is_preprint":false},{"pmid":"31327155","id":"PMC_31327155","title":"ELMO Domain Containing 1 (ELMOD1) Gene Mutation Is Associated with Mental Retardation and Autism Spectrum Disorder.","date":"2019","source":"Journal of molecular neuroscience : MN","url":"https://pubmed.ncbi.nlm.nih.gov/31327155","citation_count":8,"is_preprint":false},{"pmid":"37208194","id":"PMC_37208194","title":"WDR31 displays functional redundancy with GTPase-activating proteins (GAPs) ELMOD and RP2 in regulating IFT complex and recruiting the BBSome to cilium.","date":"2023","source":"Life science alliance","url":"https://pubmed.ncbi.nlm.nih.gov/37208194","citation_count":6,"is_preprint":false},{"pmid":"34287648","id":"PMC_34287648","title":"The glycoprotein GP130 governs the surface presentation of the G protein-coupled receptor APLNR.","date":"2021","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/34287648","citation_count":4,"is_preprint":false},{"pmid":"37437553","id":"PMC_37437553","title":"Genome-Wide Association Studies for Albuminuria of Nondiabetic Taiwanese Population.","date":"2023","source":"American journal of nephrology","url":"https://pubmed.ncbi.nlm.nih.gov/37437553","citation_count":3,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":9939,"output_tokens":2040,"usd":0.030208,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9069,"output_tokens":2852,"usd":0.058322,"stage2_stop_reason":"end_turn"},"total_usd":0.08853,"stage1_batch_id":"msgbatch_01AsR7g8dGTEiEw9U83bJeWn","stage2_batch_id":"msgbatch_01YV5ZyxtFNUZEjxRcpd9jzb","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2007,\n      \"finding\": \"ELMOD1 was found to have ARL2 GTPase-activating protein (GAP) activity, similar to its paralog ELMOD2 purified from bovine testis.\",\n      \"method\": \"In vitro GAP activity assay on purified/recombinant protein\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct biochemical assay of GAP activity, foundational finding replicated in subsequent studies\",\n      \"pmids\": [\"17452337\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"The ELMO domain of ELMOD1 contains a highly conserved arginine residue critical for GAP activity toward ARF family GTPases; mutagenesis of this residue abolished both biochemical and cellular GAP activity. ELMOD1 was also shown to act as an ARF family GAP at the Golgi.\",\n      \"method\": \"Unbiased phylogenetic analysis, sequence alignments, three independent biochemical/cellular GAP assays, active-site mutagenesis, subcellular localization (Golgi)\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — active-site mutagenesis combined with three orthogonal GAP assays and cellular localization in a single rigorous study\",\n      \"pmids\": [\"23014990\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Loss-of-function mutations in mouse Elmod1 (rda and rda2J alleles) cause cochlear hair cell dysfunction characterized by elongation and fusion of inner hair cell stereocilia and progressive degeneration of outer hair cell stereocilia, linking ELMOD1-mediated GTPase signaling to actin cytoskeleton dynamics in stereocilia.\",\n      \"method\": \"Positional cloning of naturally occurring mouse mutations, histology/morphological analysis of hair cell stereocilia\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean loss-of-function genetic model with specific cellular phenotype, but mechanism inferred rather than directly demonstrated in this paper\",\n      \"pmids\": [\"22558334\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Recombinant ELMOD1 displays GAP activity with distinct specificities toward multiple ARF family GTPases. The non-opioid sigma-1 receptor (S1R) was identified as a novel effector that directly binds ELMOD1 and inhibits its GAP activity.\",\n      \"method\": \"Overexpression in HEK293T cells, purification, in vitro GAP activity assays, direct binding assay (S1R binding to ELMOD1 inhibiting GAP activity)\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstituted GAP assays with purified proteins plus direct binding inhibition assay, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"24616099\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"ELMOD1 acts as a GAP for ARF6 in vestibular hair cells; loss of ELMOD1 in rda/rda mice leads to elevated ARF6-GTP/GDP ratio, invasion of vesicles into the cuticular plate, apical membrane lifting, and stereocilia elongation/fusion. ARF6-GTP levels correlated with phenotype severity, indicating ELMOD1-mediated ARF6-GDP conversion stabilizes apical hair cell structures.\",\n      \"method\": \"Analysis of rda/rda knockout mice, FM1-43 membrane trafficking assay, ARF6 GTP/GDP ratio measurement by biochemical assay, correlation of ARF6-GTP levels with phenotype severity\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean genetic loss-of-function model with direct measurement of ARF6 GTP/GDP ratio as mechanistic readout, multiple orthogonal methods\",\n      \"pmids\": [\"29222402\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"ELMOD1 (and ELMOD3) localizes to the Golgi and cilia, and its deletion impairs primary cilia formation, causes loss of a subset of ciliary proteins from cilia, and leads to accumulation of ciliary proteins at the Golgi, consistent with compromised Golgi-to-cilia trafficking. These phenotypes are rescued by activating mutant expression of ARL3 or ARL16, placing ELMOD1 upstream of these ARF-family GTPases in the ciliogenesis pathway.\",\n      \"method\": \"Elmod1 knockout mouse embryonic fibroblasts, ciliogenesis assays, immunofluorescence localization, genetic epistasis with ARL3/ARL16 activating mutants\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean KO model with defined phenotype, genetic epistasis with activating mutants, direct localization, replicated across two paralogs\",\n      \"pmids\": [\"34818063\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"ELMOD1 mediates the surface presentation of the G protein-coupled receptor APLNR at the plasma membrane of glioblastoma stem-like cells downstream of the glycoprotein GP130, potentially via ARF-mediated endovesicular trafficking.\",\n      \"method\": \"Co-immunoprecipitation, surface receptor presentation assays in GSCs, functional self-renewal assays with GP130 interference\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, ELMOD1's role is inferred from GP130-APLNR interaction context with limited direct mechanistic evidence for ELMOD1 specifically\",\n      \"pmids\": [\"34287648\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"The C. elegans ELMOD ortholog ELMD-1, together with WDR31 and RP-2, regulates IFT complex assembly at the ciliary base and BBSome entry/exit from cilia; triple loss-of-function causes accumulation of IFT Complex B components and KIF17 in cilia and increased anterograde IFT speed, and allows a non-ciliary protein to leak into cilia.\",\n      \"method\": \"C. elegans and zebrafish genetics, IFT particle tracking by live imaging, genetic epistasis (triple mutant wdr-31;rpi-2;elmd-1)\",\n      \"journal\": \"Life science alliance\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic model in C. elegans with live IFT imaging, but contribution of ELMD-1 specifically is assessed in a triple mutant context making individual contributions harder to isolate\",\n      \"pmids\": [\"37208194\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ELMOD1 is an ELMO domain-containing GTPase-activating protein (GAP) with activity toward ARF family GTPases (including ARF6, ARL2, and others), operating at the Golgi and in cilia to regulate Golgi-to-cilia protein trafficking, ciliogenesis, and stabilization of apical actin/membrane structures in sensory hair cells via conversion of ARF6 to its GDP-bound form; its GAP activity is inhibited by direct binding of the sigma-1 receptor, and it functions upstream of ARL3/ARL16 in the ciliogenesis pathway.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"ELMOD1 is an ELMO domain-containing GTPase-activating protein (GAP) that regulates ARF-family GTPase signaling at the Golgi and cilia, governing membrane trafficking, ciliogenesis, and apical actin/membrane organization [#1, #5]. Its GAP activity was first established biochemically toward ARL2 [#0] and extended to multiple ARF-family GTPases, with a single conserved arginine residue in the ELMO domain being essential for catalysis at the Golgi [#1]. In sensory hair cells ELMOD1 converts ARF6 to its GDP-bound state, and its loss elevates the ARF6-GTP/GDP ratio, causing vesicle invasion into the cuticular plate, apical membrane lifting, and stereocilia elongation and fusion [#2, #4]. ELMOD1 also acts upstream of ARL3 and ARL16 in ciliogenesis, where its deletion impairs primary cilium formation and Golgi-to-cilia trafficking, phenotypes rescued by activating ARL3 or ARL16 mutants [#5]. The sigma-1 receptor binds ELMOD1 directly and inhibits its GAP activity, defining a regulatory effector input [#3].\",\n  \"teleology\": [\n    {\n      \"year\": 2007,\n      \"claim\": \"Establishing whether ELMOD1 has intrinsic enzymatic activity, the first study showed it functions as a GAP toward ARL2, defining its core biochemical role.\",\n      \"evidence\": \"In vitro GAP activity assay on purified protein from bovine testis\",\n      \"pmids\": [\"17452337\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specificity beyond ARL2 not addressed\", \"Catalytic residues not yet mapped\", \"No cellular context established\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"To determine how ELMOD1 catalyzes GTP hydrolysis and where it acts, mutagenesis identified a conserved arginine essential for GAP activity toward ARF-family GTPases and localized activity to the Golgi.\",\n      \"evidence\": \"Phylogenetic analysis, three orthogonal GAP assays, active-site mutagenesis, subcellular localization\",\n      \"pmids\": [\"23014990\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full set of physiological GTPase substrates not defined\", \"Recruitment mechanism to Golgi unknown\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Linking ELMOD1 to organismal phenotype, loss-of-function mouse alleles tied the gene to hair cell stereocilia integrity, implicating GTPase signaling in actin cytoskeleton dynamics.\",\n      \"evidence\": \"Positional cloning of mouse rda/rda2J alleles, stereocilia histology\",\n      \"pmids\": [\"22558334\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism inferred, not demonstrated in this study\", \"Which GTPase mediates the actin phenotype not identified\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Addressing how ELMOD1 GAP activity is regulated, the sigma-1 receptor was identified as a direct binding effector that inhibits ELMOD1 GAP activity, and the enzyme's distinct specificities across ARF-family GTPases were resolved.\",\n      \"evidence\": \"Recombinant protein purification, in vitro GAP assays, direct binding inhibition assay\",\n      \"pmids\": [\"24616099\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological relevance of S1R inhibition in tissues untested\", \"Stoichiometry and binding interface not defined\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Connecting biochemistry to the hair cell phenotype, ELMOD1 was shown to act as an ARF6 GAP whose loss elevates ARF6-GTP and destabilizes apical membrane/actin structures, providing a direct mechanistic readout.\",\n      \"evidence\": \"rda/rda knockout mice, FM1-43 trafficking assay, ARF6 GTP/GDP ratio measurement correlated with phenotype severity\",\n      \"pmids\": [\"29222402\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How ARF6-GDP conversion stabilizes apical structures mechanistically unresolved\", \"Effectors downstream of ARF6 not identified\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Placing ELMOD1 in the ciliogenesis pathway, deletion impaired cilium formation and Golgi-to-cilia trafficking, with rescue by activating ARL3/ARL16 mutants establishing ELMOD1 upstream of these GTPases.\",\n      \"evidence\": \"Elmod1 knockout MEFs, ciliogenesis assays, immunofluorescence, genetic epistasis with ARL3/ARL16 activating mutants\",\n      \"pmids\": [\"34818063\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct GAP action on ARL3/ARL16 versus pathway position not biochemically distinguished\", \"Identity of mislocalized ciliary cargo subset incomplete\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Exploring a disease context, ELMOD1 was linked to surface presentation of the GPCR APLNR in glioblastoma stem-like cells downstream of GP130, suggesting a role in receptor trafficking.\",\n      \"evidence\": \"Co-immunoprecipitation, surface receptor assays, self-renewal functional assays in GSCs\",\n      \"pmids\": [\"34287648\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"ELMOD1 role inferred from GP130-APLNR context with limited direct mechanistic evidence\", \"ARF-dependence of the trafficking not demonstrated\", \"Single lab, no reciprocal validation\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Extending ciliary function across species, the C. elegans ortholog ELMD-1 was shown to regulate IFT complex assembly and BBSome ciliary entry/exit, with triple mutants disrupting IFT speed and ciliary protein gating.\",\n      \"evidence\": \"C. elegans and zebrafish genetics, live IFT particle tracking, triple-mutant epistasis\",\n      \"pmids\": [\"37208194\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Individual ELMD-1 contribution obscured by triple-mutant analysis\", \"Conservation of this IFT role in mammalian ELMOD1 untested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How ELMOD1 GAP activity toward distinct ARF-family GTPases is spatially partitioned between Golgi, cilia, and the hair cell apex, and how a single GAP coordinates these distinct trafficking outputs, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of ELMOD1 bound to substrate GTPases\", \"Recruitment/targeting determinants across compartments unknown\", \"Direct versus indirect relationship to ARL3/ARL16 not biochemically settled\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 3, 4]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [1, 4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [1, 5]},\n      {\"term_id\": \"GO:0005929\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [4, 5]},\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"ARF6\", \"ARL2\", \"ARL3\", \"ARL16\", \"SIGMAR1\"],\n    \"other_free_text\": []\n  }\n}\n```","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":5,"faith_pct":80.0}}