{"gene":"IPCEF1","run_date":"2026-04-28T18:06:54","timeline":{"discoveries":[{"year":2003,"finding":"IPCEF1 binds cytohesin 2 via its C-terminal 121 amino acids, which interact with the coiled-coil domain of cytohesin 2; IPCEF1 also interacts with other cytohesin family ARF GEFs, suggesting conserved interaction across the family.","method":"Yeast two-hybrid screening, GST pull-down assays with deletion mutational analysis, co-immunoprecipitation in mammalian cells","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 — multiple orthogonal methods (Y2H, GST pulldown, co-IP) with deletion mutagenesis mapping interaction domains, single lab but rigorous","pmids":["12920129"],"is_preprint":false},{"year":2003,"finding":"IPCEF1 co-localizes with cytohesin 2 in the cytosol in unstimulated cells and translocates to the plasma membrane via binding to cytohesin 2 upon EGF stimulation; a deletion mutant lacking the cytohesin 2 binding site fails to co-migrate to the membrane.","method":"Immunofluorescence microscopy in EGF-stimulated mammalian cells; deletion mutant analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — direct localization experiment with functional consequence demonstrated through mutant, single lab with multiple methods","pmids":["12920129"],"is_preprint":false},{"year":2003,"finding":"IPCEF1 enhances cytohesin 2-stimulated ARF GTP formation both in vitro and in vivo, demonstrating that IPCEF1 positively modulates cytohesin 2 GEF activity toward ARF6.","method":"In vitro ARF GEF activity assay; in vivo ARF-GTP pull-down assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — in vitro enzymatic assay plus in vivo confirmation, single lab with orthogonal methods","pmids":["12920129"],"is_preprint":false},{"year":2011,"finding":"IPCEF1 is actually the C-terminal half of CNK3 (CNKSR3), and both MDCK and CaCo-2 cells express a fused CNK3/IPCEF1 protein; knockdown of this fused protein impairs HGF-induced Arf6 activation and cell migration.","method":"Molecular cloning/sequence analysis; siRNA knockdown with Arf6-GTP pull-down assay and migration assay","journal":"Experimental cell research","confidence":"High","confidence_rationale":"Tier 2 — loss-of-function with defined molecular readout (Arf6 activation) and cellular phenotype (migration), orthogonal biochemical and functional methods","pmids":["22085542"],"is_preprint":false},{"year":2009,"finding":"IPCEF1 mRNA is expressed in rat dorsal root ganglia (DRGs) and is significantly upregulated following peripheral nerve injury (spinal nerve ligation/transection or sciatic nerve transection), suggesting a role in nerve injury-induced membrane receptor trafficking in DRG neurons.","method":"Quantitative RT-PCR in rat DRG tissue after nerve injury models","journal":"Naunyn-Schmiedeberg's archives of pharmacology","confidence":"Low","confidence_rationale":"Tier 3 — expression measurement in vivo without functional mechanistic follow-up; correlative in nature","pmids":["19756519"],"is_preprint":false},{"year":2021,"finding":"Enforced expression of Ipcef1 in Th17 cells abolishes TLR2-dependent increases in migratory capacity and severely impairs the ability of Th17 cells to induce experimental autoimmune encephalomyelitis (EAE), revealing a role for IPCEF1 in regulating Th17 cell migration and pathogenicity.","method":"Retroviral enforced overexpression in Th17 cells; transwell migration assay; in vivo EAE model","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 — gain-of-function with defined cellular phenotype (migration) and in vivo disease readout, single lab","pmids":["34192530"],"is_preprint":false},{"year":2024,"finding":"High expression of IPCEF1 in PTC cells causes cell cycle arrest in the S or G2 phase and reduces proliferation and migration capacity of PTC cells, consistent with a tumor suppressor role.","method":"CCK8 proliferation assay, transwell migration assay, flow cytometry cell cycle analysis in PTC cell lines","journal":"Journal of Cancer","confidence":"Medium","confidence_rationale":"Tier 2-3 — multiple functional assays in cell lines but no upstream mechanism identified; single lab","pmids":["39513122"],"is_preprint":false}],"current_model":"IPCEF1 (which constitutes the C-terminal half of the CNK3/CNKSR3 scaffold protein) binds the coiled-coil domain of cytohesin 2 through its C-terminal 121 amino acids, co-localizes with cytohesin 2 in the cytosol and translocates with it to the plasma membrane upon growth factor stimulation, and enhances cytohesin 2 GEF activity to promote ARF6 activation, thereby facilitating HGF-induced epithelial cell migration; in Th17 cells, IPCEF1 negatively regulates TLR2-driven migration and pathogenicity, and in thyroid epithelial cancer cells it acts as a tumor suppressor by inducing cell cycle arrest."},"narrative":{"teleology":[{"year":2003,"claim":"The discovery that IPCEF1 physically binds the coiled-coil domain of cytohesin 2 and enhances its GEF activity toward ARF6 established IPCEF1 as a direct positive modulator of ARF signaling, answering how cytohesin 2 catalytic output is amplified.","evidence":"Yeast two-hybrid, GST pull-down with deletion mutants, co-IP, in vitro ARF GEF assay, and in vivo ARF-GTP pull-down in mammalian cells","pmids":["12920129"],"confidence":"High","gaps":["Structural basis of the IPCEF1–cytohesin 2 interaction is unresolved","Mechanism by which IPCEF1 binding enhances GEF catalytic activity is not defined","Whether IPCEF1 modulates cytohesin activity in a tissue-specific manner was not addressed"]},{"year":2003,"claim":"Demonstrating that IPCEF1 co-localizes with cytohesin 2 in the cytosol and translocates to the plasma membrane upon EGF stimulation — dependent on the cytohesin 2 binding site — established the spatial regulation mechanism coupling receptor activation to ARF6 signaling at the membrane.","evidence":"Immunofluorescence microscopy with EGF stimulation and deletion mutant lacking cytohesin 2 binding domain","pmids":["12920129"],"confidence":"High","gaps":["Whether IPCEF1 also functions independently of cytohesin 2 at the membrane was not tested","The signal that triggers IPCEF1–cytohesin 2 complex translocation (PI(3,4,5)P3 or other) was not dissected"]},{"year":2011,"claim":"The finding that IPCEF1 is the C-terminal half of the CNK3/CNKSR3 scaffold protein, and that knockdown of this fused protein impairs HGF-induced ARF6 activation and cell migration, connected IPCEF1 function to a larger signaling scaffold and established its physiological relevance in epithelial cell migration.","evidence":"Molecular cloning/sequence analysis; siRNA knockdown with ARF6-GTP pull-down and migration assay in MDCK and CaCo-2 cells","pmids":["22085542"],"confidence":"High","gaps":["Whether the IPCEF1 portion functions autonomously when separated from the CNK3 N-terminal scaffold domains is unclear","Signaling inputs from HGF receptor to the CNK3/IPCEF1 fusion remain unmapped"]},{"year":2021,"claim":"Enforced IPCEF1 expression in Th17 cells abolished TLR2-driven migration and impaired EAE induction, revealing that IPCEF1 negatively regulates immune cell migration and pathogenic T cell function in an autoimmune context — extending its role beyond epithelial biology.","evidence":"Retroviral overexpression in Th17 cells; transwell migration assay; in vivo EAE model","pmids":["34192530"],"confidence":"Medium","gaps":["Whether IPCEF1 acts through cytohesin 2/ARF6 in Th17 cells or through an alternative pathway was not determined","Loss-of-function in Th17 cells was not reported","Mechanism linking IPCEF1 to TLR2 signaling is unknown"]},{"year":2024,"claim":"High IPCEF1 expression induced S/G2 cell cycle arrest and reduced proliferation and migration in papillary thyroid cancer cells, establishing a tumor-suppressive function for IPCEF1 in this cancer type.","evidence":"CCK8 proliferation assay, transwell migration assay, flow cytometry cell cycle analysis in PTC cell lines","pmids":["39513122"],"confidence":"Medium","gaps":["Upstream regulators of IPCEF1 expression in PTC are unknown","The mechanism by which IPCEF1 induces cell cycle arrest (direct target, pathway) was not identified","No in vivo tumor model was used"]},{"year":null,"claim":"It remains unknown how IPCEF1 mechanistically shifts between promoting migration (via ARF6 in epithelial cells) and suppressing migration (in Th17 and cancer cells), and the structural basis by which IPCEF1 enhances cytohesin 2 catalysis has not been resolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No structural model of the IPCEF1–cytohesin 2 complex exists","Context-dependent pro- vs. anti-migratory functions are mechanistically unexplained","Whether IPCEF1 has functions independent of cytohesin/ARF signaling remains untested"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,2]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[1]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[1]}],"pathway":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[1]}],"complexes":["CNK3/CNKSR3 scaffold"],"partners":["CYTH2","ARF6","CNKSR3"],"other_free_text":[]},"mechanistic_narrative":"IPCEF1 functions as a positive regulator of cytohesin 2 (ARNO) guanine-nucleotide exchange factor (GEF) activity toward ARF6, thereby coupling growth factor signaling to membrane trafficking and cell migration. IPCEF1 binds the coiled-coil domain of cytohesin 2 through its C-terminal 121 amino acids, co-localizes with cytohesin 2 in the cytosol, and translocates with it to the plasma membrane upon EGF stimulation; this interaction enhances ARF6-GTP loading both in vitro and in vivo [PMID:12920129]. IPCEF1 constitutes the C-terminal half of the CNK3/CNKSR3 scaffold protein, and knockdown of the fused CNK3/IPCEF1 protein impairs HGF-induced ARF6 activation and epithelial cell migration [PMID:22085542]. Beyond its role in epithelial migration, enforced IPCEF1 expression in Th17 cells abolishes TLR2-driven migratory capacity and attenuates experimental autoimmune encephalomyelitis [PMID:34192530], and high IPCEF1 expression in papillary thyroid cancer cells induces cell cycle arrest and reduces proliferation [PMID:39513122]."},"prefetch_data":{"uniprot":{"accession":"Q8WWN9","full_name":"Interactor protein for cytohesin exchange factors 1","aliases":["Phosphoinositide-binding protein PIP3-E"],"length_aa":437,"mass_kda":49.0,"function":"Enhances the promotion of guanine-nucleotide exchange by PSCD2 on ARF6 in a concentration-dependent manner","subcellular_location":"Cytoplasm; Cell membrane","url":"https://www.uniprot.org/uniprotkb/Q8WWN9/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/IPCEF1","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/IPCEF1","total_profiled":1310},"omim":[{"mim_id":"619948","title":"INTERACTION PROTEIN FOR CYTOHESIN EXCHANGE FACTORS 1; IPCEF1","url":"https://www.omim.org/entry/619948"},{"mim_id":"617476","title":"CNKSR FAMILY, MEMBER 3; CNKSR3","url":"https://www.omim.org/entry/617476"},{"mim_id":"612027","title":"TRAFFICKING REGULATOR AND SCAFFOLD PROTEIN TAMALIN; TAMALIN","url":"https://www.omim.org/entry/612027"},{"mim_id":"602488","title":"CYTOHESIN 2; CYTH2","url":"https://www.omim.org/entry/602488"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nuclear speckles","reliability":"Approved"},{"location":"Plasma membrane","reliability":"Approved"},{"location":"Nucleoli","reliability":"Additional"},{"location":"Cytoplasmic bodies","reliability":"Additional"}],"tissue_specificity":"Group enriched","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"bone marrow","ntpm":15.8},{"tissue":"brain","ntpm":18.1},{"tissue":"lymphoid tissue","ntpm":12.6},{"tissue":"thyroid gland","ntpm":34.0}],"url":"https://www.proteinatlas.org/search/IPCEF1"},"hgnc":{"alias_symbol":["PIP3-E","KIAA0403"],"prev_symbol":[]},"alphafold":{"accession":"Q8WWN9","domains":[{"cath_id":"2.30.29.30","chopping":"31-141","consensus_level":"high","plddt":88.4663,"start":31,"end":141},{"cath_id":"-","chopping":"351-409","consensus_level":"high","plddt":88.6668,"start":351,"end":409}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8WWN9","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8WWN9-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8WWN9-F1-predicted_aligned_error_v6.png","plddt_mean":64.06},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=IPCEF1","jax_strain_url":"https://www.jax.org/strain/search?query=IPCEF1"},"sequence":{"accession":"Q8WWN9","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8WWN9.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8WWN9/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8WWN9"}},"corpus_meta":[{"pmid":"26305897","id":"PMC_26305897","title":"Genome-Wide Association and Trans-ethnic Meta-Analysis for Advanced Diabetic Kidney Disease: Family Investigation of Nephropathy and Diabetes (FIND).","date":"2015","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/26305897","citation_count":107,"is_preprint":false},{"pmid":"12920129","id":"PMC_12920129","title":"Interaction protein for cytohesin exchange factors 1 (IPCEF1) binds cytohesin 2 and modifies its activity.","date":"2003","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12920129","citation_count":53,"is_preprint":false},{"pmid":"29679657","id":"PMC_29679657","title":"Eleven loci with new reproducible genetic associations with allergic disease risk.","date":"2018","source":"The Journal of allergy and clinical immunology","url":"https://pubmed.ncbi.nlm.nih.gov/29679657","citation_count":52,"is_preprint":false},{"pmid":"22085542","id":"PMC_22085542","title":"CNK3 and IPCEF1 produce a single protein that is required for HGF dependent Arf6 activation and migration.","date":"2011","source":"Experimental cell research","url":"https://pubmed.ncbi.nlm.nih.gov/22085542","citation_count":27,"is_preprint":false},{"pmid":"34192530","id":"PMC_34192530","title":"Toll-like receptor 2 induces pathogenicity in Th17 cells and reveals a role for IPCEF in regulating Th17 cell migration.","date":"2021","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/34192530","citation_count":21,"is_preprint":false},{"pmid":"34545296","id":"PMC_34545296","title":"Oxidative Stress Genes in Diabetes Mellitus Type 2: Association with Diabetic Kidney Disease.","date":"2021","source":"Oxidative medicine and cellular longevity","url":"https://pubmed.ncbi.nlm.nih.gov/34545296","citation_count":21,"is_preprint":false},{"pmid":"25863487","id":"PMC_25863487","title":"Somatic amplifications and deletions in genome of papillary thyroid carcinomas.","date":"2015","source":"Endocrine","url":"https://pubmed.ncbi.nlm.nih.gov/25863487","citation_count":20,"is_preprint":false},{"pmid":"19756519","id":"PMC_19756519","title":"Peripheral nerve injury up-regulates expression of interactor protein for cytohesin exchange factor 1 (IPCEF1) mRNA in rat dorsal root ganglion.","date":"2009","source":"Naunyn-Schmiedeberg's archives of pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/19756519","citation_count":12,"is_preprint":false},{"pmid":"34165176","id":"PMC_34165176","title":"Circular RNA profiling reveals a potential role of hsa_circ_IPCEF1 in papillary thyroid carcinoma.","date":"2021","source":"Molecular medicine reports","url":"https://pubmed.ncbi.nlm.nih.gov/34165176","citation_count":10,"is_preprint":false},{"pmid":"36465624","id":"PMC_36465624","title":"Screening and validation of lymph node metastasis risk-factor genes in papillary thyroid carcinoma.","date":"2022","source":"Frontiers in endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/36465624","citation_count":9,"is_preprint":false},{"pmid":"35634509","id":"PMC_35634509","title":"Construction of a Signature Model to Predict the Radioactive Iodine Response of Papillary Thyroid Cancer.","date":"2022","source":"Frontiers in endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/35634509","citation_count":4,"is_preprint":false},{"pmid":"39513122","id":"PMC_39513122","title":"IPCEF1: Expression Patterns, Clinical Correlates and New Target of Papillary Thyroid Carcinoma.","date":"2024","source":"Journal of Cancer","url":"https://pubmed.ncbi.nlm.nih.gov/39513122","citation_count":2,"is_preprint":false},{"pmid":"41661231","id":"PMC_41661231","title":"RNAseq-based meta-analyses revealed tumor suppressor-inducer fusion events in liver, oral, and ovarian cancer in the Indian population: a cancer cell surviving mechanism.","date":"2026","source":"Nucleosides, nucleotides & nucleic acids","url":"https://pubmed.ncbi.nlm.nih.gov/41661231","citation_count":0,"is_preprint":false},{"pmid":"41937365","id":"PMC_41937365","title":"Placental DNA methylation mediates the prenatal maternal stress-childhood allergy association: A cohort study.","date":"2026","source":"Pediatric allergy and immunology : official publication of the European Society of Pediatric Allergy and Immunology","url":"https://pubmed.ncbi.nlm.nih.gov/41937365","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":8837,"output_tokens":1627,"usd":0.025458},"stage2":{"model":"claude-opus-4-6","input_tokens":4881,"output_tokens":3843,"usd":0.18072},"total_usd":0.206178,"stage1_batch_id":"msgbatch_01DzrsgVgYngY1hvM3DU1yF2","stage2_batch_id":"msgbatch_01KA9b7iRzKFdhoBUT7vCvSe","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2003,\n      \"finding\": \"IPCEF1 binds cytohesin 2 via its C-terminal 121 amino acids, which interact with the coiled-coil domain of cytohesin 2; IPCEF1 also interacts with other cytohesin family ARF GEFs, suggesting conserved interaction across the family.\",\n      \"method\": \"Yeast two-hybrid screening, GST pull-down assays with deletion mutational analysis, co-immunoprecipitation in mammalian cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — multiple orthogonal methods (Y2H, GST pulldown, co-IP) with deletion mutagenesis mapping interaction domains, single lab but rigorous\",\n      \"pmids\": [\"12920129\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"IPCEF1 co-localizes with cytohesin 2 in the cytosol in unstimulated cells and translocates to the plasma membrane via binding to cytohesin 2 upon EGF stimulation; a deletion mutant lacking the cytohesin 2 binding site fails to co-migrate to the membrane.\",\n      \"method\": \"Immunofluorescence microscopy in EGF-stimulated mammalian cells; deletion mutant analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct localization experiment with functional consequence demonstrated through mutant, single lab with multiple methods\",\n      \"pmids\": [\"12920129\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"IPCEF1 enhances cytohesin 2-stimulated ARF GTP formation both in vitro and in vivo, demonstrating that IPCEF1 positively modulates cytohesin 2 GEF activity toward ARF6.\",\n      \"method\": \"In vitro ARF GEF activity assay; in vivo ARF-GTP pull-down assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro enzymatic assay plus in vivo confirmation, single lab with orthogonal methods\",\n      \"pmids\": [\"12920129\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"IPCEF1 is actually the C-terminal half of CNK3 (CNKSR3), and both MDCK and CaCo-2 cells express a fused CNK3/IPCEF1 protein; knockdown of this fused protein impairs HGF-induced Arf6 activation and cell migration.\",\n      \"method\": \"Molecular cloning/sequence analysis; siRNA knockdown with Arf6-GTP pull-down assay and migration assay\",\n      \"journal\": \"Experimental cell research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function with defined molecular readout (Arf6 activation) and cellular phenotype (migration), orthogonal biochemical and functional methods\",\n      \"pmids\": [\"22085542\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"IPCEF1 mRNA is expressed in rat dorsal root ganglia (DRGs) and is significantly upregulated following peripheral nerve injury (spinal nerve ligation/transection or sciatic nerve transection), suggesting a role in nerve injury-induced membrane receptor trafficking in DRG neurons.\",\n      \"method\": \"Quantitative RT-PCR in rat DRG tissue after nerve injury models\",\n      \"journal\": \"Naunyn-Schmiedeberg's archives of pharmacology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — expression measurement in vivo without functional mechanistic follow-up; correlative in nature\",\n      \"pmids\": [\"19756519\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Enforced expression of Ipcef1 in Th17 cells abolishes TLR2-dependent increases in migratory capacity and severely impairs the ability of Th17 cells to induce experimental autoimmune encephalomyelitis (EAE), revealing a role for IPCEF1 in regulating Th17 cell migration and pathogenicity.\",\n      \"method\": \"Retroviral enforced overexpression in Th17 cells; transwell migration assay; in vivo EAE model\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — gain-of-function with defined cellular phenotype (migration) and in vivo disease readout, single lab\",\n      \"pmids\": [\"34192530\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"High expression of IPCEF1 in PTC cells causes cell cycle arrest in the S or G2 phase and reduces proliferation and migration capacity of PTC cells, consistent with a tumor suppressor role.\",\n      \"method\": \"CCK8 proliferation assay, transwell migration assay, flow cytometry cell cycle analysis in PTC cell lines\",\n      \"journal\": \"Journal of Cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — multiple functional assays in cell lines but no upstream mechanism identified; single lab\",\n      \"pmids\": [\"39513122\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"IPCEF1 (which constitutes the C-terminal half of the CNK3/CNKSR3 scaffold protein) binds the coiled-coil domain of cytohesin 2 through its C-terminal 121 amino acids, co-localizes with cytohesin 2 in the cytosol and translocates with it to the plasma membrane upon growth factor stimulation, and enhances cytohesin 2 GEF activity to promote ARF6 activation, thereby facilitating HGF-induced epithelial cell migration; in Th17 cells, IPCEF1 negatively regulates TLR2-driven migration and pathogenicity, and in thyroid epithelial cancer cells it acts as a tumor suppressor by inducing cell cycle arrest.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"IPCEF1 functions as a positive regulator of cytohesin 2 (ARNO) guanine-nucleotide exchange factor (GEF) activity toward ARF6, thereby coupling growth factor signaling to membrane trafficking and cell migration. IPCEF1 binds the coiled-coil domain of cytohesin 2 through its C-terminal 121 amino acids, co-localizes with cytohesin 2 in the cytosol, and translocates with it to the plasma membrane upon EGF stimulation; this interaction enhances ARF6-GTP loading both in vitro and in vivo [PMID:12920129]. IPCEF1 constitutes the C-terminal half of the CNK3/CNKSR3 scaffold protein, and knockdown of the fused CNK3/IPCEF1 protein impairs HGF-induced ARF6 activation and epithelial cell migration [PMID:22085542]. Beyond its role in epithelial migration, enforced IPCEF1 expression in Th17 cells abolishes TLR2-driven migratory capacity and attenuates experimental autoimmune encephalomyelitis [PMID:34192530], and high IPCEF1 expression in papillary thyroid cancer cells induces cell cycle arrest and reduces proliferation [PMID:39513122].\",\n  \"teleology\": [\n    {\n      \"year\": 2003,\n      \"claim\": \"The discovery that IPCEF1 physically binds the coiled-coil domain of cytohesin 2 and enhances its GEF activity toward ARF6 established IPCEF1 as a direct positive modulator of ARF signaling, answering how cytohesin 2 catalytic output is amplified.\",\n      \"evidence\": \"Yeast two-hybrid, GST pull-down with deletion mutants, co-IP, in vitro ARF GEF assay, and in vivo ARF-GTP pull-down in mammalian cells\",\n      \"pmids\": [\"12920129\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Structural basis of the IPCEF1–cytohesin 2 interaction is unresolved\",\n        \"Mechanism by which IPCEF1 binding enhances GEF catalytic activity is not defined\",\n        \"Whether IPCEF1 modulates cytohesin activity in a tissue-specific manner was not addressed\"\n      ]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Demonstrating that IPCEF1 co-localizes with cytohesin 2 in the cytosol and translocates to the plasma membrane upon EGF stimulation — dependent on the cytohesin 2 binding site — established the spatial regulation mechanism coupling receptor activation to ARF6 signaling at the membrane.\",\n      \"evidence\": \"Immunofluorescence microscopy with EGF stimulation and deletion mutant lacking cytohesin 2 binding domain\",\n      \"pmids\": [\"12920129\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether IPCEF1 also functions independently of cytohesin 2 at the membrane was not tested\",\n        \"The signal that triggers IPCEF1–cytohesin 2 complex translocation (PI(3,4,5)P3 or other) was not dissected\"\n      ]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"The finding that IPCEF1 is the C-terminal half of the CNK3/CNKSR3 scaffold protein, and that knockdown of this fused protein impairs HGF-induced ARF6 activation and cell migration, connected IPCEF1 function to a larger signaling scaffold and established its physiological relevance in epithelial cell migration.\",\n      \"evidence\": \"Molecular cloning/sequence analysis; siRNA knockdown with ARF6-GTP pull-down and migration assay in MDCK and CaCo-2 cells\",\n      \"pmids\": [\"22085542\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether the IPCEF1 portion functions autonomously when separated from the CNK3 N-terminal scaffold domains is unclear\",\n        \"Signaling inputs from HGF receptor to the CNK3/IPCEF1 fusion remain unmapped\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Enforced IPCEF1 expression in Th17 cells abolished TLR2-driven migration and impaired EAE induction, revealing that IPCEF1 negatively regulates immune cell migration and pathogenic T cell function in an autoimmune context — extending its role beyond epithelial biology.\",\n      \"evidence\": \"Retroviral overexpression in Th17 cells; transwell migration assay; in vivo EAE model\",\n      \"pmids\": [\"34192530\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether IPCEF1 acts through cytohesin 2/ARF6 in Th17 cells or through an alternative pathway was not determined\",\n        \"Loss-of-function in Th17 cells was not reported\",\n        \"Mechanism linking IPCEF1 to TLR2 signaling is unknown\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"High IPCEF1 expression induced S/G2 cell cycle arrest and reduced proliferation and migration in papillary thyroid cancer cells, establishing a tumor-suppressive function for IPCEF1 in this cancer type.\",\n      \"evidence\": \"CCK8 proliferation assay, transwell migration assay, flow cytometry cell cycle analysis in PTC cell lines\",\n      \"pmids\": [\"39513122\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Upstream regulators of IPCEF1 expression in PTC are unknown\",\n        \"The mechanism by which IPCEF1 induces cell cycle arrest (direct target, pathway) was not identified\",\n        \"No in vivo tumor model was used\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unknown how IPCEF1 mechanistically shifts between promoting migration (via ARF6 in epithelial cells) and suppressing migration (in Th17 and cancer cells), and the structural basis by which IPCEF1 enhances cytohesin 2 catalysis has not been resolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No structural model of the IPCEF1–cytohesin 2 complex exists\",\n        \"Context-dependent pro- vs. anti-migratory functions are mechanistically unexplained\",\n        \"Whether IPCEF1 has functions independent of cytohesin/ARF signaling remains untested\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"complexes\": [\"CNK3/CNKSR3 scaffold\"],\n    \"partners\": [\"CYTH2\", \"ARF6\", \"CNKSR3\"],\n    \"other_free_text\": []\n  }\n}\n```\n\nWait, I made an error in the pathway field — I used a GO term instead of a Reactome pathway. Let me correct that.\n\n```json\n{\n  \"mechanistic_narrative\": \"IPCEF1 functions as a positive regulator of cytohesin 2 (ARNO) guanine-nucleotide exchange factor (GEF) activity toward ARF6, thereby coupling growth factor signaling to membrane trafficking and cell migration. IPCEF1 binds the coiled-coil domain of cytohesin 2 through its C-terminal 121 amino acids, co-localizes with cytohesin 2 in the cytosol, and translocates with it to the plasma membrane upon EGF stimulation; this interaction enhances ARF6-GTP loading both in vitro and in vivo [PMID:12920129]. IPCEF1 constitutes the C-terminal half of the CNK3/CNKSR3 scaffold protein, and knockdown of the fused CNK3/IPCEF1 protein impairs HGF-induced ARF6 activation and epithelial cell migration [PMID:22085542]. Beyond its role in epithelial migration, enforced IPCEF1 expression in Th17 cells abolishes TLR2-driven migratory capacity and attenuates experimental autoimmune encephalomyelitis [PMID:34192530], and high IPCEF1 expression in papillary thyroid cancer cells induces cell cycle arrest and reduces proliferation [PMID:39513122].\",\n  \"teleology\": [\n    {\n      \"year\": 2003,\n      \"claim\": \"The discovery that IPCEF1 physically binds the coiled-coil domain of cytohesin 2 and enhances its GEF activity toward ARF6 established IPCEF1 as a direct positive modulator of ARF signaling, answering how cytohesin 2 catalytic output is amplified.\",\n      \"evidence\": \"Yeast two-hybrid, GST pull-down with deletion mutants, co-IP, in vitro ARF GEF assay, and in vivo ARF-GTP pull-down in mammalian cells\",\n      \"pmids\": [\"12920129\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Structural basis of the IPCEF1–cytohesin 2 interaction is unresolved\",\n        \"Mechanism by which IPCEF1 binding enhances GEF catalytic activity is not defined\",\n        \"Whether IPCEF1 modulates cytohesin activity in a tissue-specific manner was not addressed\"\n      ]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Demonstrating that IPCEF1 co-localizes with cytohesin 2 in the cytosol and translocates to the plasma membrane upon EGF stimulation — dependent on the cytohesin 2 binding site — established the spatial regulation mechanism coupling receptor activation to ARF6 signaling at the membrane.\",\n      \"evidence\": \"Immunofluorescence microscopy with EGF stimulation and deletion mutant lacking cytohesin 2 binding domain\",\n      \"pmids\": [\"12920129\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether IPCEF1 also functions independently of cytohesin 2 at the membrane was not tested\",\n        \"The signal that triggers IPCEF1–cytohesin 2 complex translocation (PI(3,4,5)P3 or other) was not dissected\"\n      ]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"The finding that IPCEF1 is the C-terminal half of the CNK3/CNKSR3 scaffold protein, and that knockdown of this fused protein impairs HGF-induced ARF6 activation and cell migration, connected IPCEF1 function to a larger signaling scaffold and established its physiological relevance in epithelial cell migration.\",\n      \"evidence\": \"Molecular cloning/sequence analysis; siRNA knockdown with ARF6-GTP pull-down and migration assay in MDCK and CaCo-2 cells\",\n      \"pmids\": [\"22085542\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether the IPCEF1 portion functions autonomously when separated from the CNK3 N-terminal scaffold domains is unclear\",\n        \"Signaling inputs from HGF receptor to the CNK3/IPCEF1 fusion remain unmapped\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Enforced IPCEF1 expression in Th17 cells abolished TLR2-driven migration and impaired EAE induction, revealing that IPCEF1 negatively regulates immune cell migration and pathogenic T cell function in an autoimmune context — extending its role beyond epithelial biology.\",\n      \"evidence\": \"Retroviral overexpression in Th17 cells; transwell migration assay; in vivo EAE model\",\n      \"pmids\": [\"34192530\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether IPCEF1 acts through cytohesin 2/ARF6 in Th17 cells or through an alternative pathway was not determined\",\n        \"Loss-of-function in Th17 cells was not reported\",\n        \"Mechanism linking IPCEF1 to TLR2 signaling is unknown\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"High IPCEF1 expression induced S/G2 cell cycle arrest and reduced proliferation and migration in papillary thyroid cancer cells, establishing a tumor-suppressive function for IPCEF1 in this cancer type.\",\n      \"evidence\": \"CCK8 proliferation assay, transwell migration assay, flow cytometry cell cycle analysis in PTC cell lines\",\n      \"pmids\": [\"39513122\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Upstream regulators of IPCEF1 expression in PTC are unknown\",\n        \"The mechanism by which IPCEF1 induces cell cycle arrest (direct target, pathway) was not identified\",\n        \"No in vivo tumor model was used\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unknown how IPCEF1 mechanistically shifts between promoting migration (via ARF6 in epithelial cells) and suppressing migration (in Th17 and cancer cells), and the structural basis by which IPCEF1 enhances cytohesin 2 catalysis has not been resolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No structural model of the IPCEF1–cytohesin 2 complex exists\",\n        \"Context-dependent pro- vs. anti-migratory functions are mechanistically unexplained\",\n        \"Whether IPCEF1 has functions independent of cytohesin/ARF signaling remains untested\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 2, 3]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"complexes\": [\"CNK3/CNKSR3 scaffold\"],\n    \"partners\": [\"CYTH2\", \"ARF6\", \"CNKSR3\"],\n    \"other_free_text\": []\n  }\n}\n```"}