{"gene":"DENND1C","run_date":"2026-04-28T17:46:02","timeline":{"discoveries":[{"year":2010,"finding":"DENND1C (along with DENND1A and DENND1B) functions as a Rab GEF; specifically, DENND1C activates Rab13 via its DENN domain. The 17 human DENN domain proteins were systematically shown to be specific GEFs for 10 Rabs.","method":"Systematic family-wide characterization including GEF activity assays, subcellular localization studies","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 1-2 — systematic biochemical characterization across full protein family with functional assays, widely replicated","pmids":["20937701"],"is_preprint":false},{"year":2011,"finding":"DENND1C (connecdenn 3) binds actin directly via a unique C-terminal motif not found in DENND1A or DENND1B, coupling Rab35 activation to the actin cytoskeleton and inducing protrusive membrane extensions. The actin-binding motif and N-terminal DENN domain (GEF activity) are both required for this effect. DENND1C and Rab35 colocalize with fascin and actin filaments, identifying DENND1C as the relevant GEF for Rab35-mediated fascin recruitment.","method":"Direct actin-binding assay, mutagenesis of actin-binding motif and DENN domain, colocalization by fluorescence microscopy, cell morphology assays","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 1-2 — direct binding assay combined with domain mutagenesis and functional phenotypic readout in single rigorous study","pmids":["22072793"],"is_preprint":false},{"year":2014,"finding":"In lymphocytes, the kinase Mst1 promotes phosphorylation of DENND1C in response to chemokine stimulation, which activates Rab13. Active Rab13 then associates with Mst1 to facilitate delivery of integrin LFA-1 to the leading edge via myosin Va along actin filaments, enabling lymphocyte adhesion and migration.","method":"Phosphorylation assays, Rab13 activity assays, knockdown/inhibition of Rab13 with adhesion and migration readouts, colocalization studies in T lymphocytes","journal":"Science signaling","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (kinase assay, GEF activation, functional migration/adhesion assays, in vivo Rab13-KO mice) in a single rigorous study","pmids":["25074980"],"is_preprint":false},{"year":2019,"finding":"IL-17A stimulation recruits DENND1C (as a GEF for Rab35) to the IL-17R/Act1 complex in airway smooth muscle cells, leading to Rab35 activation, PKCα activation, fascin phosphorylation at Ser39, stress fiber formation, and enhanced smooth muscle contraction.","method":"Co-immunoprecipitation of DENND1C with IL-17R/Act1 complex, Rab35 knockdown with functional contraction readouts, PKCα inhibitor experiments","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2-3 — Co-IP plus functional knockdown with defined phenotype, single lab","pmids":["30683702"],"is_preprint":false},{"year":2020,"finding":"Among four known Rab35 GEFs (DENND1A, DENND1B, DENND1C, FLCN), DENND1C knockout did not phenocopy Rab35 knockout for podocalyxin trafficking in either 2D or 3D MDCK cell cultures, indicating that DENND1C is dispensable for these specific Rab35-dependent trafficking pathways (which are instead governed by DENND1A and FLCN).","method":"CRISPR/knockout of individual DENN-domain GEFs in MDCK cells, podocalyxin localization assays in 2D and 3D cultures","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 — clean KO with defined trafficking phenotype, but finding is negative/null for DENND1C specifically","pmids":["31992598"],"is_preprint":false}],"current_model":"DENND1C is a DENN-domain Rab guanine nucleotide exchange factor (GEF) that activates both Rab35 and Rab13: it activates Rab35 specifically at the actin cytoskeleton via a unique C-terminal actin-binding motif to drive fascin recruitment and protrusive membrane extensions, activates Rab13 downstream of Mst1 kinase phosphorylation in lymphocytes to deliver integrin LFA-1 to the leading edge for cell migration, and is recruited to the IL-17R/Act1 complex to activate Rab35 and promote PKCα-dependent stress fiber formation in airway smooth muscle cells."},"narrative":{"teleology":[{"year":2010,"claim":"Systematic biochemical profiling established that DENND1C is a bona fide Rab GEF with specificity for Rab13, placing it within a family of 17 DENN-domain proteins that collectively activate 10 distinct Rabs.","evidence":"Family-wide GEF activity assays and subcellular localization across all human DENN-domain proteins","pmids":["20937701"],"confidence":"High","gaps":["Whether DENND1C also activates Rabs other than Rab13 was not resolved in this screen","Upstream regulation of DENND1C GEF activity was unknown","Physiological cellular functions of DENND1C-Rab13 axis were uncharacterized"]},{"year":2011,"claim":"DENND1C was shown to directly bind actin through a unique C-terminal motif and to activate Rab35 (not only Rab13), coupling Rab35 GEF activity to the actin cytoskeleton and driving fascin-dependent protrusive membrane extensions — a function not shared by DENND1A or DENND1B.","evidence":"Direct actin-binding assays, DENN-domain and actin-binding motif mutagenesis, colocalization microscopy, and cell morphology analysis","pmids":["22072793"],"confidence":"High","gaps":["The relative contributions of Rab13 versus Rab35 activation by DENND1C in vivo were not delineated","Structural basis of the C-terminal actin-binding motif interaction was not determined","Cell-type specificity of DENND1C-driven protrusions was unexplored"]},{"year":2014,"claim":"A signaling cascade was defined in which chemokine-stimulated Mst1 kinase phosphorylates DENND1C to activate Rab13, which then partners with Mst1 and myosin Va to deliver LFA-1 integrin to the leading edge for lymphocyte adhesion and migration.","evidence":"Phosphorylation assays, Rab13 activation assays, knockdown/inhibition with adhesion and migration readouts in T lymphocytes, and Rab13-knockout mice","pmids":["25074980"],"confidence":"High","gaps":["The specific phosphorylation site(s) on DENND1C and their mechanistic effect on GEF activity were not fully resolved","Whether DENND1C phosphorylation similarly regulates Rab35 activation was untested","Contribution of DENND1C versus other Rab13 GEFs in lymphocyte biology in vivo was not dissected"]},{"year":2019,"claim":"DENND1C was found to be recruited to the IL-17R/Act1 signaling complex in airway smooth muscle cells, linking IL-17A cytokine signaling to Rab35 activation, PKCα-dependent fascin phosphorylation, stress fiber formation, and enhanced contractility.","evidence":"Co-immunoprecipitation of DENND1C with IL-17R/Act1, Rab35 knockdown with contraction readouts, PKCα inhibitor experiments","pmids":["30683702"],"confidence":"Medium","gaps":["Recruitment mechanism of DENND1C to the IL-17R/Act1 complex (direct binding vs. adaptor) was not defined","Findings are from a single laboratory and have not been independently replicated","Whether this pathway operates in other IL-17-responsive cell types was not tested"]},{"year":2020,"claim":"Genetic knockout experiments clarified that DENND1C is dispensable for Rab35-dependent podocalyxin trafficking in epithelial cells, demonstrating that DENND1C's Rab35-GEF function is context-specific rather than universally required.","evidence":"CRISPR knockout of individual DENN-domain GEFs in MDCK cells with podocalyxin localization in 2D and 3D culture","pmids":["31992598"],"confidence":"Medium","gaps":["The specific cell types and trafficking pathways where DENND1C is the essential Rab35 GEF remain incompletely mapped","Compensatory mechanisms among DENN-family GEFs were not tested","Negative result in one epithelial model does not exclude roles in other epithelial contexts"]},{"year":null,"claim":"The structural basis for DENND1C's dual Rab specificity (Rab13 and Rab35), the precise phosphorylation sites controlling its GEF activity, and the in vivo physiological consequences of DENND1C loss in whole organisms remain unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No crystal or cryo-EM structure of DENND1C DENN domain bound to Rab13 or Rab35","No DENND1C-knockout mouse phenotype reported","How DENND1C GEF activity is switched between Rab13 and Rab35 substrates is unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1,2,3]}],"localization":[{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[1]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[1,2]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[2,3]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[2,3]}],"complexes":[],"partners":["RAB35","RAB13","MST1","ACT1","FSCN1"],"other_free_text":[]},"mechanistic_narrative":"DENND1C is a DENN-domain Rab guanine nucleotide exchange factor (GEF) that activates both Rab13 and Rab35 in distinct cellular contexts to regulate actin-dependent membrane dynamics and cell migration [PMID:20937701, PMID:22072793, PMID:25074980]. A unique C-terminal actin-binding motif, absent from paralogous DENND1A and DENND1B, directly tethers DENND1C to actin filaments, coupling Rab35 activation to fascin recruitment and the formation of protrusive membrane extensions [PMID:22072793]. In lymphocytes, Mst1 kinase-dependent phosphorylation of DENND1C activates Rab13, which in turn drives myosin Va-dependent delivery of integrin LFA-1 to the leading edge to support adhesion and migration [PMID:25074980]. DENND1C is also recruited to the IL-17R/Act1 signaling complex in airway smooth muscle cells, where it activates Rab35 to promote PKCα-dependent stress fiber formation and contraction [PMID:30683702]."},"prefetch_data":{"uniprot":{"accession":"Q8IV53","full_name":"DENN domain-containing protein 1C","aliases":["Connecdenn 3","Protein FAM31C"],"length_aa":801,"mass_kda":87.1,"function":"Guanine nucleotide exchange factor (GEF) which may activate RAB8A, RAB13 and RAB35. Promotes the exchange of GDP to GTP, converting inactive GDP-bound Rab proteins into their active GTP-bound form","subcellular_location":"Cytoplasm, cytosol; Cytoplasmic vesicle, clathrin-coated vesicle","url":"https://www.uniprot.org/uniprotkb/Q8IV53/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/DENND1C","classification":"Not Classified","n_dependent_lines":16,"n_total_lines":1208,"dependency_fraction":0.013245033112582781},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/DENND1C","total_profiled":1310},"omim":[{"mim_id":"613634","title":"DENN/MADD DOMAIN-CONTAINING PROTEIN 1C; DENND1C","url":"https://www.omim.org/entry/613634"},{"mim_id":"613633","title":"DENN/MADD DOMAIN-CONTAINING PROTEIN 1A; DENND1A","url":"https://www.omim.org/entry/613633"},{"mim_id":"613292","title":"DENN/MADD DOMAIN-CONTAINING PROTEIN 1B; DENND1B","url":"https://www.omim.org/entry/613292"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Cytosol","reliability":"Approved"},{"location":"Nucleoplasm","reliability":"Additional"},{"location":"Centrosome","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"bone marrow","ntpm":20.0},{"tissue":"intestine","ntpm":13.8},{"tissue":"lymphoid tissue","ntpm":34.2}],"url":"https://www.proteinatlas.org/search/DENND1C"},"hgnc":{"alias_symbol":["FLJ22757"],"prev_symbol":["FAM31C"]},"alphafold":{"accession":"Q8IV53","domains":[{"cath_id":"3.30.450.200","chopping":"16-138","consensus_level":"high","plddt":91.9631,"start":16,"end":138},{"cath_id":"3.40.50.11500","chopping":"191-335","consensus_level":"medium","plddt":95.9257,"start":191,"end":335},{"cath_id":"-","chopping":"341-430","consensus_level":"medium","plddt":85.2143,"start":341,"end":430}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8IV53","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8IV53-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8IV53-F1-predicted_aligned_error_v6.png","plddt_mean":62.94},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=DENND1C","jax_strain_url":"https://www.jax.org/strain/search?query=DENND1C"},"sequence":{"accession":"Q8IV53","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8IV53.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8IV53/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8IV53"}},"corpus_meta":[{"pmid":"20937701","id":"PMC_20937701","title":"Family-wide characterization of the DENN domain Rab GDP-GTP exchange factors.","date":"2010","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/20937701","citation_count":279,"is_preprint":false},{"pmid":"25651499","id":"PMC_25651499","title":"An analysis of DNA methylation in human adipose tissue reveals differential modification of obesity genes before and after gastric bypass and weight loss.","date":"2015","source":"Genome biology","url":"https://pubmed.ncbi.nlm.nih.gov/25651499","citation_count":199,"is_preprint":false},{"pmid":"25074980","id":"PMC_25074980","title":"Rab13 acts downstream of the kinase Mst1 to deliver the integrin LFA-1 to the cell surface for lymphocyte trafficking.","date":"2014","source":"Science signaling","url":"https://pubmed.ncbi.nlm.nih.gov/25074980","citation_count":61,"is_preprint":false},{"pmid":"22072793","id":"PMC_22072793","title":"Connecdenn 3/DENND1C binds actin linking Rab35 activation to the actin cytoskeleton.","date":"2011","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/22072793","citation_count":47,"is_preprint":false},{"pmid":"36588164","id":"PMC_36588164","title":"PCSK9 facilitates melanoma pathogenesis via a network regulating tumor immunity.","date":"2023","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/36588164","citation_count":32,"is_preprint":false},{"pmid":"27312686","id":"PMC_27312686","title":"Biological significance of genome-wide DNA methylation profiles in keloids.","date":"2016","source":"The Laryngoscope","url":"https://pubmed.ncbi.nlm.nih.gov/27312686","citation_count":24,"is_preprint":false},{"pmid":"30683702","id":"PMC_30683702","title":"IL-17A Recruits Rab35 to IL-17R to Mediate PKCα-Dependent Stress Fiber Formation and Airway Smooth Muscle Contractility.","date":"2019","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/30683702","citation_count":15,"is_preprint":false},{"pmid":"31992598","id":"PMC_31992598","title":"Rab35-GEFs, DENND1A and folliculin differentially regulate podocalyxin trafficking in two- and three-dimensional epithelial cell cultures.","date":"2020","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/31992598","citation_count":9,"is_preprint":false},{"pmid":"40306147","id":"PMC_40306147","title":"Identification of shared pathophysiological molecules of major psychiatric disorders: A comprehensive analysis of serum immune complex antigens before and after electroconvulsive therapy.","date":"2025","source":"Journal of neuroimmunology","url":"https://pubmed.ncbi.nlm.nih.gov/40306147","citation_count":1,"is_preprint":false},{"pmid":"41031217","id":"PMC_41031217","title":"Identification of Progression-Associated Biomarkers in Lung Cancer Based on the Integrated Analysis of RNA Sequencing Data From Platelets and Tumor Tissues.","date":"2025","source":"International journal of genomics","url":"https://pubmed.ncbi.nlm.nih.gov/41031217","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.10.11.25337587","title":"Machine Learning for Predicting and Maximizing the Response of Breast Cancer Patients to Neoadjuvant Therapy","date":"2025-10-14","source":"bioRxiv","url":"https://doi.org/10.1101/2025.10.11.25337587","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7614,"output_tokens":1423,"usd":0.022093},"stage2":{"model":"claude-opus-4-6","input_tokens":4655,"output_tokens":4007,"usd":0.185175},"total_usd":0.207268,"stage1_batch_id":"msgbatch_0118RScg3WGaGkaZRtWZbtce","stage2_batch_id":"msgbatch_01Cpfzvtbj42aqp5oYZ5Te2s","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2010,\n      \"finding\": \"DENND1C (along with DENND1A and DENND1B) functions as a Rab GEF; specifically, DENND1C activates Rab13 via its DENN domain. The 17 human DENN domain proteins were systematically shown to be specific GEFs for 10 Rabs.\",\n      \"method\": \"Systematic family-wide characterization including GEF activity assays, subcellular localization studies\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — systematic biochemical characterization across full protein family with functional assays, widely replicated\",\n      \"pmids\": [\"20937701\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"DENND1C (connecdenn 3) binds actin directly via a unique C-terminal motif not found in DENND1A or DENND1B, coupling Rab35 activation to the actin cytoskeleton and inducing protrusive membrane extensions. The actin-binding motif and N-terminal DENN domain (GEF activity) are both required for this effect. DENND1C and Rab35 colocalize with fascin and actin filaments, identifying DENND1C as the relevant GEF for Rab35-mediated fascin recruitment.\",\n      \"method\": \"Direct actin-binding assay, mutagenesis of actin-binding motif and DENN domain, colocalization by fluorescence microscopy, cell morphology assays\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — direct binding assay combined with domain mutagenesis and functional phenotypic readout in single rigorous study\",\n      \"pmids\": [\"22072793\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"In lymphocytes, the kinase Mst1 promotes phosphorylation of DENND1C in response to chemokine stimulation, which activates Rab13. Active Rab13 then associates with Mst1 to facilitate delivery of integrin LFA-1 to the leading edge via myosin Va along actin filaments, enabling lymphocyte adhesion and migration.\",\n      \"method\": \"Phosphorylation assays, Rab13 activity assays, knockdown/inhibition of Rab13 with adhesion and migration readouts, colocalization studies in T lymphocytes\",\n      \"journal\": \"Science signaling\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (kinase assay, GEF activation, functional migration/adhesion assays, in vivo Rab13-KO mice) in a single rigorous study\",\n      \"pmids\": [\"25074980\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"IL-17A stimulation recruits DENND1C (as a GEF for Rab35) to the IL-17R/Act1 complex in airway smooth muscle cells, leading to Rab35 activation, PKCα activation, fascin phosphorylation at Ser39, stress fiber formation, and enhanced smooth muscle contraction.\",\n      \"method\": \"Co-immunoprecipitation of DENND1C with IL-17R/Act1 complex, Rab35 knockdown with functional contraction readouts, PKCα inhibitor experiments\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — Co-IP plus functional knockdown with defined phenotype, single lab\",\n      \"pmids\": [\"30683702\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Among four known Rab35 GEFs (DENND1A, DENND1B, DENND1C, FLCN), DENND1C knockout did not phenocopy Rab35 knockout for podocalyxin trafficking in either 2D or 3D MDCK cell cultures, indicating that DENND1C is dispensable for these specific Rab35-dependent trafficking pathways (which are instead governed by DENND1A and FLCN).\",\n      \"method\": \"CRISPR/knockout of individual DENN-domain GEFs in MDCK cells, podocalyxin localization assays in 2D and 3D cultures\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clean KO with defined trafficking phenotype, but finding is negative/null for DENND1C specifically\",\n      \"pmids\": [\"31992598\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"DENND1C is a DENN-domain Rab guanine nucleotide exchange factor (GEF) that activates both Rab35 and Rab13: it activates Rab35 specifically at the actin cytoskeleton via a unique C-terminal actin-binding motif to drive fascin recruitment and protrusive membrane extensions, activates Rab13 downstream of Mst1 kinase phosphorylation in lymphocytes to deliver integrin LFA-1 to the leading edge for cell migration, and is recruited to the IL-17R/Act1 complex to activate Rab35 and promote PKCα-dependent stress fiber formation in airway smooth muscle cells.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"DENND1C is a DENN-domain Rab guanine nucleotide exchange factor (GEF) that activates both Rab13 and Rab35 in distinct cellular contexts to regulate actin-dependent membrane dynamics and cell migration [PMID:20937701, PMID:22072793, PMID:25074980]. A unique C-terminal actin-binding motif, absent from paralogous DENND1A and DENND1B, directly tethers DENND1C to actin filaments, coupling Rab35 activation to fascin recruitment and the formation of protrusive membrane extensions [PMID:22072793]. In lymphocytes, Mst1 kinase-dependent phosphorylation of DENND1C activates Rab13, which in turn drives myosin Va-dependent delivery of integrin LFA-1 to the leading edge to support adhesion and migration [PMID:25074980]. DENND1C is also recruited to the IL-17R/Act1 signaling complex in airway smooth muscle cells, where it activates Rab35 to promote PKCα-dependent stress fiber formation and contraction [PMID:30683702].\",\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"Systematic biochemical profiling established that DENND1C is a bona fide Rab GEF with specificity for Rab13, placing it within a family of 17 DENN-domain proteins that collectively activate 10 distinct Rabs.\",\n      \"evidence\": \"Family-wide GEF activity assays and subcellular localization across all human DENN-domain proteins\",\n      \"pmids\": [\"20937701\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether DENND1C also activates Rabs other than Rab13 was not resolved in this screen\",\n        \"Upstream regulation of DENND1C GEF activity was unknown\",\n        \"Physiological cellular functions of DENND1C-Rab13 axis were uncharacterized\"\n      ]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"DENND1C was shown to directly bind actin through a unique C-terminal motif and to activate Rab35 (not only Rab13), coupling Rab35 GEF activity to the actin cytoskeleton and driving fascin-dependent protrusive membrane extensions — a function not shared by DENND1A or DENND1B.\",\n      \"evidence\": \"Direct actin-binding assays, DENN-domain and actin-binding motif mutagenesis, colocalization microscopy, and cell morphology analysis\",\n      \"pmids\": [\"22072793\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"The relative contributions of Rab13 versus Rab35 activation by DENND1C in vivo were not delineated\",\n        \"Structural basis of the C-terminal actin-binding motif interaction was not determined\",\n        \"Cell-type specificity of DENND1C-driven protrusions was unexplored\"\n      ]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"A signaling cascade was defined in which chemokine-stimulated Mst1 kinase phosphorylates DENND1C to activate Rab13, which then partners with Mst1 and myosin Va to deliver LFA-1 integrin to the leading edge for lymphocyte adhesion and migration.\",\n      \"evidence\": \"Phosphorylation assays, Rab13 activation assays, knockdown/inhibition with adhesion and migration readouts in T lymphocytes, and Rab13-knockout mice\",\n      \"pmids\": [\"25074980\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"The specific phosphorylation site(s) on DENND1C and their mechanistic effect on GEF activity were not fully resolved\",\n        \"Whether DENND1C phosphorylation similarly regulates Rab35 activation was untested\",\n        \"Contribution of DENND1C versus other Rab13 GEFs in lymphocyte biology in vivo was not dissected\"\n      ]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"DENND1C was found to be recruited to the IL-17R/Act1 signaling complex in airway smooth muscle cells, linking IL-17A cytokine signaling to Rab35 activation, PKCα-dependent fascin phosphorylation, stress fiber formation, and enhanced contractility.\",\n      \"evidence\": \"Co-immunoprecipitation of DENND1C with IL-17R/Act1, Rab35 knockdown with contraction readouts, PKCα inhibitor experiments\",\n      \"pmids\": [\"30683702\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Recruitment mechanism of DENND1C to the IL-17R/Act1 complex (direct binding vs. adaptor) was not defined\",\n        \"Findings are from a single laboratory and have not been independently replicated\",\n        \"Whether this pathway operates in other IL-17-responsive cell types was not tested\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Genetic knockout experiments clarified that DENND1C is dispensable for Rab35-dependent podocalyxin trafficking in epithelial cells, demonstrating that DENND1C's Rab35-GEF function is context-specific rather than universally required.\",\n      \"evidence\": \"CRISPR knockout of individual DENN-domain GEFs in MDCK cells with podocalyxin localization in 2D and 3D culture\",\n      \"pmids\": [\"31992598\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"The specific cell types and trafficking pathways where DENND1C is the essential Rab35 GEF remain incompletely mapped\",\n        \"Compensatory mechanisms among DENN-family GEFs were not tested\",\n        \"Negative result in one epithelial model does not exclude roles in other epithelial contexts\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural basis for DENND1C's dual Rab specificity (Rab13 and Rab35), the precise phosphorylation sites controlling its GEF activity, and the in vivo physiological consequences of DENND1C loss in whole organisms remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No crystal or cryo-EM structure of DENND1C DENN domain bound to Rab13 or Rab35\",\n        \"No DENND1C-knockout mouse phenotype reported\",\n        \"How DENND1C GEF activity is switched between Rab13 and Rab35 substrates is unknown\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 2, 3]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1, 2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0009609507\", \"supporting_discovery_ids\": [2, 3]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [2, 3]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [2, 3]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"RAB35\",\n      \"RAB13\",\n      \"MST1\",\n      \"ACT1\",\n      \"FSCN1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```\n\nWait, I need to fix the pathway term_ids. Let me correct:\n\n```json\n{\n  \"mechanistic_narrative\": \"DENND1C is a DENN-domain Rab guanine nucleotide exchange factor (GEF) that activates both Rab13 and Rab35 in distinct cellular contexts to regulate actin-dependent membrane dynamics and cell migration [PMID:20937701, PMID:22072793, PMID:25074980]. A unique C-terminal actin-binding motif, absent from paralogous DENND1A and DENND1B, directly tethers DENND1C to actin filaments, coupling Rab35 activation to fascin recruitment and the formation of protrusive membrane extensions [PMID:22072793]. In lymphocytes, Mst1 kinase-dependent phosphorylation of DENND1C activates Rab13, which in turn drives myosin Va-dependent delivery of integrin LFA-1 to the leading edge to support adhesion and migration [PMID:25074980]. DENND1C is also recruited to the IL-17R/Act1 signaling complex in airway smooth muscle cells, where it activates Rab35 to promote PKCα-dependent stress fiber formation and contraction [PMID:30683702].\",\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"Systematic biochemical profiling established that DENND1C is a bona fide Rab GEF with specificity for Rab13, placing it within a family of 17 DENN-domain proteins that collectively activate 10 distinct Rabs.\",\n      \"evidence\": \"Family-wide GEF activity assays and subcellular localization across all human DENN-domain proteins\",\n      \"pmids\": [\"20937701\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether DENND1C also activates Rabs other than Rab13 was not resolved in this screen\",\n        \"Upstream regulation of DENND1C GEF activity was unknown\",\n        \"Physiological cellular functions of DENND1C-Rab13 axis were uncharacterized\"\n      ]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"DENND1C was shown to directly bind actin through a unique C-terminal motif and to activate Rab35 (not only Rab13), coupling Rab35 GEF activity to the actin cytoskeleton and driving fascin-dependent protrusive membrane extensions — a function not shared by DENND1A or DENND1B.\",\n      \"evidence\": \"Direct actin-binding assays, DENN-domain and actin-binding motif mutagenesis, colocalization microscopy, and cell morphology analysis\",\n      \"pmids\": [\"22072793\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"The relative contributions of Rab13 versus Rab35 activation by DENND1C in vivo were not delineated\",\n        \"Structural basis of the C-terminal actin-binding motif interaction was not determined\",\n        \"Cell-type specificity of DENND1C-driven protrusions was unexplored\"\n      ]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"A signaling cascade was defined in which chemokine-stimulated Mst1 kinase phosphorylates DENND1C to activate Rab13, which then partners with Mst1 and myosin Va to deliver LFA-1 integrin to the leading edge for lymphocyte adhesion and migration.\",\n      \"evidence\": \"Phosphorylation assays, Rab13 activation assays, knockdown/inhibition with adhesion and migration readouts in T lymphocytes, and Rab13-knockout mice\",\n      \"pmids\": [\"25074980\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"The specific phosphorylation site(s) on DENND1C and their mechanistic effect on GEF activity were not fully resolved\",\n        \"Whether DENND1C phosphorylation similarly regulates Rab35 activation was untested\",\n        \"Contribution of DENND1C versus other Rab13 GEFs in lymphocyte biology in vivo was not dissected\"\n      ]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"DENND1C was found to be recruited to the IL-17R/Act1 signaling complex in airway smooth muscle cells, linking IL-17A cytokine signaling to Rab35 activation, PKCα-dependent fascin phosphorylation, stress fiber formation, and enhanced contractility.\",\n      \"evidence\": \"Co-immunoprecipitation of DENND1C with IL-17R/Act1, Rab35 knockdown with contraction readouts, PKCα inhibitor experiments\",\n      \"pmids\": [\"30683702\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Recruitment mechanism of DENND1C to the IL-17R/Act1 complex (direct binding vs. adaptor) was not defined\",\n        \"Findings are from a single laboratory and have not been independently replicated\",\n        \"Whether this pathway operates in other IL-17-responsive cell types was not tested\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Genetic knockout experiments clarified that DENND1C is dispensable for Rab35-dependent podocalyxin trafficking in epithelial cells, demonstrating that DENND1C's Rab35-GEF function is context-specific rather than universally required.\",\n      \"evidence\": \"CRISPR knockout of individual DENN-domain GEFs in MDCK cells with podocalyxin localization in 2D and 3D culture\",\n      \"pmids\": [\"31992598\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"The specific cell types and trafficking pathways where DENND1C is the essential Rab35 GEF remain incompletely mapped\",\n        \"Compensatory mechanisms among DENN-family GEFs were not tested\",\n        \"Negative result in one epithelial model does not exclude roles in other epithelial contexts\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural basis for DENND1C's dual Rab specificity (Rab13 and Rab35), the precise phosphorylation sites controlling its GEF activity, and the in vivo physiological consequences of DENND1C loss in whole organisms remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No crystal or cryo-EM structure of DENND1C DENN domain bound to Rab13 or Rab35\",\n        \"No DENND1C-knockout mouse phenotype reported\",\n        \"How DENND1C GEF activity is switched between Rab13 and Rab35 substrates is unknown\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 2, 3]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [2, 3]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [2, 3]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [2, 3]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"RAB35\",\n      \"RAB13\",\n      \"STK4\",\n      \"TRAF3IP2\",\n      \"FSCN1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}