{"gene":"EPN2","run_date":"2026-06-09T23:54:43","timeline":{"discoveries":[{"year":2009,"finding":"Combined genetic inactivation of epsin 1 (Epn1) and epsin 2 (Epn2) in mice causes embryonic lethality at E9.5-E10 with developmental defects recapitulating global impairment of Notch signaling; expression of Notch primary target genes was severely reduced in double-knockout embryos, establishing epsins as specialized endocytic adaptors required for Notch signaling activation. Housekeeping clathrin-mediated endocytosis was not impaired in cells from these embryos.","method":"Epn1/Epn2 double-knockout mice (genetic epistasis); analysis of Notch target gene expression; endocytosis assays in derived cells","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean double-KO mouse model with defined developmental phenotype, Notch target gene expression analysis, and negative result for housekeeping endocytosis; multiple orthogonal readouts in one rigorous study","pmids":["19666558"],"is_preprint":false},{"year":2013,"finding":"Endothelial-specific deletion of Epn1 and Epn2 causes elevated VEGFR2 levels and aberrant angiogenesis; genetic reduction of VEGFR2 by one allele (Flk1 heterozygosity) rescues defective VEGF signaling, EC proliferation, EC migration, EC network formation, and in vivo angiogenesis, demonstrating that epsins function specifically to downregulate VEGFR2 by mediating activated VEGFR2 internalization and degradation.","method":"Conditional endothelial-specific Epn1/Epn2 double-knockout mice combined with Flk1 heterozygosity (genetic epistasis); in vitro angiogenesis assays with primary ECs; in vivo wound healing, inflammatory angiogenesis, and tumor angiogenesis assays","journal":"Arteriosclerosis, thrombosis, and vascular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis with multiple in vitro and in vivo orthogonal assays, direct rescue experiment, multiple labs confirmed the broader epsin-VEGFR2 axis","pmids":["24311377"],"is_preprint":false},{"year":2020,"finding":"Podocyte-specific triple knockout of Epn1, Epn2, and Epn3 results in albuminuria, foot process effacement, and defects in cell adhesion and spreading, attributed to reduced activation of Cdc42 and downstream SRF, leading to diminished β1 integrin expression; this places epsins upstream of a Cdc42-SRF-β1 integrin axis in podocyte function.","method":"Podocyte-specific triple-KO mice (Epn1/2/3); albuminuria measurement; primary podocyte cell adhesion and spreading assays; Cdc42 activation assay; SRF and β1 integrin expression analysis","journal":"Journal of the American Society of Nephrology : JASN","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KO with defined cellular phenotype and pathway placement (Cdc42-SRF-β1 integrin), but single lab and EPN2 is studied only as part of a triple-KO","pmids":["33051360"],"is_preprint":false},{"year":2017,"finding":"EPN2 (epsin2) is a direct target of miR-1224 in human endothelial cells; knockdown of EPN2 stimulates tube formation, while overexpression of EPN2 represses miR-1224-mediated stimulation of tube formation, establishing EPN2 as a suppressor of angiogenesis acting downstream of miR-1224.","method":"miR-1224 enforced expression and repression in HUVECs; EPN2 knockdown and overexpression; tube formation assay on Matrigel; direct target validation of miR-1224→EPN2","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — direct target validation with KD and OE rescue experiments in a single lab, multiple functional readouts but no in vitro reconstitution or structural data","pmids":["28717225"],"is_preprint":false},{"year":2026,"finding":"The long transcript isoform of EPN2 mediates clathrin-dependent endocytosis-dependent degradation of the Wnt receptor frizzled 7 (FZD7); suppression of the EPN2 long transcript (via circSPARC-HNRNPC alternative splicing axis) impairs FZD7 degradation, sustaining Wnt/β-catenin activation and promoting ESCC progression. Expression of the EPN2 long transcript restores Wnt/β-catenin inhibition and suppresses ESCC malignancy.","method":"RNA pull-down, RIP, RAP, alternative splicing analysis, cell surface protein biotinylation; EPN2 long transcript overexpression in vitro and in vivo; circSPARC knockdown rescue experiments","journal":"Molecular cancer","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal RNA-binding and functional methods in a single lab, with in vitro and in vivo validation; isoform-level specificity is well-supported but not yet replicated","pmids":["42210380"],"is_preprint":false}],"current_model":"EPN2 (epsin 2) is a clathrin-mediated endocytic adaptor that acts as a specialized cargo internalization factor: it is required (redundantly with EPN1) for Notch receptor activation during embryogenesis, mediates internalization and degradation of activated VEGFR2 to restrain angiogenesis, regulates FZD7 receptor turnover to limit Wnt/β-catenin signaling, and supports podocyte function through a Cdc42-SRF-β1 integrin axis—while being largely dispensable for bulk clathrin-mediated endocytosis."},"narrative":{"mechanistic_narrative":"EPN2 (epsin 2) is a specialized clathrin-mediated endocytic adaptor that selectively controls the internalization and degradation of specific signaling receptors rather than supporting bulk endocytosis [PMID:19666558]. Acting redundantly with EPN1, EPN2 is required for Notch signaling activation during embryogenesis, as combined Epn1/Epn2 loss recapitulates global Notch impairment and abolishes Notch target gene expression while leaving housekeeping clathrin-mediated endocytosis intact [PMID:19666558]. In endothelial cells, EPN2 restrains angiogenesis by mediating internalization and degradation of activated VEGFR2, since epsin loss elevates VEGFR2 and produces aberrant angiogenesis that is rescued by reducing VEGFR2 gene dosage [PMID:24311377]; consistent with this anti-angiogenic role, EPN2 acts as a suppressor of endothelial tube formation downstream of miR-1224 [PMID:28717225]. EPN2 likewise limits Wnt/β-catenin signaling: its long transcript isoform drives clathrin-dependent endocytic degradation of the Wnt receptor FZD7, and loss of this isoform sustains Wnt activation and promotes esophageal squamous cell carcinoma progression [PMID:42210380]. In podocytes, epsins (Epn1/2/3) support cell adhesion and spreading upstream of a Cdc42–SRF–β1 integrin axis, with their loss causing albuminuria and foot process effacement [PMID:33051360].","teleology":[{"year":2009,"claim":"Established that epsins are not generic endocytic machinery but specialized adaptors dedicated to receptor signaling, answering whether EPN1/EPN2 have a selective in vivo function.","evidence":"Epn1/Epn2 double-knockout mice with Notch target gene analysis and endocytosis assays in derived cells","pmids":["19666558"],"confidence":"High","gaps":["Does not resolve EPN2-specific contribution versus EPN1 redundancy","Direct biochemical link between EPN2 and Notch receptor/ligand internalization not shown","Molecular basis of cargo selectivity over bulk endocytosis unaddressed"]},{"year":2013,"claim":"Identified a specific cargo for epsin-mediated degradation by showing epsins downregulate activated VEGFR2 to restrain angiogenesis, defining a mechanistic substrate beyond Notch.","evidence":"Endothelial-specific Epn1/Epn2 double-KO combined with Flk1 heterozygosity rescue; in vitro and in vivo angiogenesis assays","pmids":["24311377"],"confidence":"High","gaps":["EPN2-specific role not separable from EPN1 in the double-KO","Direct EPN2-VEGFR2 physical interaction not biochemically defined","Mechanism distinguishing VEGFR2 from other endothelial receptors unknown"]},{"year":2017,"claim":"Placed EPN2 within a regulatory circuit by showing it acts as a miR-1224-controlled suppressor of angiogenic tube formation, linking EPN2 expression level to endothelial behavior.","evidence":"miR-1224 modulation, EPN2 knockdown/overexpression, and tube formation assays in HUVECs with direct target validation","pmids":["28717225"],"confidence":"Medium","gaps":["Single-lab study without reconstitution or structural data","Whether anti-angiogenic effect operates through VEGFR2 degradation not tested here","In vivo relevance of the miR-1224→EPN2 axis not established"]},{"year":2020,"claim":"Extended epsin function to cytoskeletal/adhesion signaling by placing epsins upstream of a Cdc42-SRF-β1 integrin axis required for podocyte function.","evidence":"Podocyte-specific Epn1/2/3 triple-KO mice; albuminuria, adhesion/spreading assays, Cdc42 activation and β1 integrin expression analysis","pmids":["33051360"],"confidence":"Medium","gaps":["EPN2 studied only within a triple-KO, so its individual contribution is unresolved","Single lab; mechanism connecting epsins to Cdc42 activation not defined","Whether the role depends on receptor endocytosis is unclear"]},{"year":2026,"claim":"Defined isoform-level specificity by showing the EPN2 long transcript drives clathrin-dependent FZD7 degradation to limit Wnt/β-catenin signaling and tumor progression.","evidence":"RNA pull-down, RIP, RAP, splicing analysis, surface biotinylation, and EPN2 long-transcript overexpression in vitro and in vivo in ESCC models","pmids":["42210380"],"confidence":"Medium","gaps":["Single lab; isoform specificity not yet independently replicated","Direct EPN2–FZD7 interaction interface not mapped","Functional difference between EPN2 transcript isoforms mechanistically undefined"]},{"year":null,"claim":"How EPN2 selects specific signaling receptors (Notch, VEGFR2, FZD7) for internalization while sparing bulk endocytosis, and how EPN2 is distinguished from EPN1/EPN3 at the molecular level, remains unresolved.","evidence":"No direct mechanistic study isolating EPN2 cargo-recognition determinants in the available corpus","pmids":[],"confidence":"Low","gaps":["No structural or biochemical map of EPN2 cargo recognition","EPN2-specific (non-redundant) functions not isolated from paralogs","Recruitment determinants distinguishing signaling cargo from bulk cargo unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,1]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[1,4]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[1,4]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[0,1,4]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,1,4]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[0]}],"complexes":[],"partners":["EPN1","VEGFR2","FZD7"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O95208","full_name":"Epsin-2","aliases":["EPS-15-interacting protein 2"],"length_aa":641,"mass_kda":68.5,"function":"Plays a role in the formation of clathrin-coated invaginations and endocytosis","subcellular_location":"Cytoplasm; Cytoplasmic vesicle, clathrin-coated vesicle","url":"https://www.uniprot.org/uniprotkb/O95208/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/EPN2","classification":"Not Classified","n_dependent_lines":15,"n_total_lines":1208,"dependency_fraction":0.012417218543046357},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000072134","cell_line_id":"CID000526","localizations":[{"compartment":"cytoplasmic","grade":3},{"compartment":"vesicles","grade":2},{"compartment":"membrane","grade":1}],"interactors":[{"gene":"ARHGAP18","stoichiometry":0.2},{"gene":"CLTA","stoichiometry":0.2},{"gene":"HIST2H2AA3;HIST2H2AC","stoichiometry":0.2},{"gene":"RPS27A;UBC;UBB;UBA52","stoichiometry":0.2},{"gene":"HIST1H2BN;HIST1H2BM;HIST1H2BH;HIST2H2BF;HIST1H2BC;HIST1H2BD;HIST1H2BK;H2BFS","stoichiometry":0.2},{"gene":"H1FX","stoichiometry":0.2},{"gene":"RAD50","stoichiometry":0.2},{"gene":"SMARCA1","stoichiometry":0.2},{"gene":"PARP1","stoichiometry":0.2},{"gene":"WHSC1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID000526","total_profiled":1310},"omim":[{"mim_id":"607264","title":"EPSIN 3; EPN3","url":"https://www.omim.org/entry/607264"},{"mim_id":"607263","title":"EPSIN 2; EPN2","url":"https://www.omim.org/entry/607263"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Vesicles","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/EPN2"},"hgnc":{"alias_symbol":["KIAA1065","EHB21"],"prev_symbol":[]},"alphafold":{"accession":"O95208","domains":[{"cath_id":"1.25.40.90","chopping":"4-158","consensus_level":"high","plddt":92.9832,"start":4,"end":158}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O95208","model_url":"https://alphafold.ebi.ac.uk/files/AF-O95208-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O95208-F1-predicted_aligned_error_v6.png","plddt_mean":59.09},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=EPN2","jax_strain_url":"https://www.jax.org/strain/search?query=EPN2"},"sequence":{"accession":"O95208","fasta_url":"https://rest.uniprot.org/uniprotkb/O95208.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O95208/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O95208"}},"corpus_meta":[{"pmid":"19666558","id":"PMC_19666558","title":"Embryonic arrest at midgestation and disruption of Notch signaling produced by the absence of both epsin 1 and epsin 2 in mice.","date":"2009","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/19666558","citation_count":96,"is_preprint":false},{"pmid":"24311377","id":"PMC_24311377","title":"Genetic reduction of vascular endothelial growth factor receptor 2 rescues aberrant angiogenesis caused by epsin deficiency.","date":"2013","source":"Arteriosclerosis, thrombosis, and vascular biology","url":"https://pubmed.ncbi.nlm.nih.gov/24311377","citation_count":42,"is_preprint":false},{"pmid":"31562977","id":"PMC_31562977","title":"LINC00473 promotes hepatocellular carcinoma progression via acting as a ceRNA for microRNA-195 and increasing HMGA2 expression.","date":"2019","source":"Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie","url":"https://pubmed.ncbi.nlm.nih.gov/31562977","citation_count":25,"is_preprint":false},{"pmid":"28717225","id":"PMC_28717225","title":"A mammalian mirtron miR-1224 promotes tube-formation of human primary endothelial cells by targeting anti-angiogenic factor epsin2.","date":"2017","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/28717225","citation_count":16,"is_preprint":false},{"pmid":"35867415","id":"PMC_35867415","title":"Proteomic Identification of Potential Target Proteins of Cathepsin W for Its Development as a Drug Target for Influenza.","date":"2022","source":"Microbiology spectrum","url":"https://pubmed.ncbi.nlm.nih.gov/35867415","citation_count":12,"is_preprint":false},{"pmid":"33051360","id":"PMC_33051360","title":"Murine Epsins Play an Integral Role in Podocyte Function.","date":"2020","source":"Journal of the American Society of Nephrology : JASN","url":"https://pubmed.ncbi.nlm.nih.gov/33051360","citation_count":4,"is_preprint":false},{"pmid":"37444635","id":"PMC_37444635","title":"Dissecting the Methylomes of EGFR-Amplified Glioblastoma Reveals Altered DNA Replication and Packaging, and Chromatin and Gene Silencing Pathways.","date":"2023","source":"Cancers","url":"https://pubmed.ncbi.nlm.nih.gov/37444635","citation_count":2,"is_preprint":false},{"pmid":"40513938","id":"PMC_40513938","title":"Mendelian randomization analysis with the GEO database: Exploring the molecular mechanism underlying insulin therapy for perioperative neurocognitive disorders.","date":"2025","source":"European journal of pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/40513938","citation_count":1,"is_preprint":false},{"pmid":"42210380","id":"PMC_42210380","title":"CircSPARC promotes esophageal squamous cell carcinoma through an HNRNPC-EPN2 splicing axis that activates Wnt/β-Catenin signaling.","date":"2026","source":"Molecular cancer","url":"https://pubmed.ncbi.nlm.nih.gov/42210380","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7164,"output_tokens":1672,"usd":0.023286,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8436,"output_tokens":2532,"usd":0.05274,"stage2_stop_reason":"end_turn"},"total_usd":0.076026,"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\": 2009,\n      \"finding\": \"Combined genetic inactivation of epsin 1 (Epn1) and epsin 2 (Epn2) in mice causes embryonic lethality at E9.5-E10 with developmental defects recapitulating global impairment of Notch signaling; expression of Notch primary target genes was severely reduced in double-knockout embryos, establishing epsins as specialized endocytic adaptors required for Notch signaling activation. Housekeeping clathrin-mediated endocytosis was not impaired in cells from these embryos.\",\n      \"method\": \"Epn1/Epn2 double-knockout mice (genetic epistasis); analysis of Notch target gene expression; endocytosis assays in derived cells\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean double-KO mouse model with defined developmental phenotype, Notch target gene expression analysis, and negative result for housekeeping endocytosis; multiple orthogonal readouts in one rigorous study\",\n      \"pmids\": [\"19666558\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Endothelial-specific deletion of Epn1 and Epn2 causes elevated VEGFR2 levels and aberrant angiogenesis; genetic reduction of VEGFR2 by one allele (Flk1 heterozygosity) rescues defective VEGF signaling, EC proliferation, EC migration, EC network formation, and in vivo angiogenesis, demonstrating that epsins function specifically to downregulate VEGFR2 by mediating activated VEGFR2 internalization and degradation.\",\n      \"method\": \"Conditional endothelial-specific Epn1/Epn2 double-knockout mice combined with Flk1 heterozygosity (genetic epistasis); in vitro angiogenesis assays with primary ECs; in vivo wound healing, inflammatory angiogenesis, and tumor angiogenesis assays\",\n      \"journal\": \"Arteriosclerosis, thrombosis, and vascular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis with multiple in vitro and in vivo orthogonal assays, direct rescue experiment, multiple labs confirmed the broader epsin-VEGFR2 axis\",\n      \"pmids\": [\"24311377\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Podocyte-specific triple knockout of Epn1, Epn2, and Epn3 results in albuminuria, foot process effacement, and defects in cell adhesion and spreading, attributed to reduced activation of Cdc42 and downstream SRF, leading to diminished β1 integrin expression; this places epsins upstream of a Cdc42-SRF-β1 integrin axis in podocyte function.\",\n      \"method\": \"Podocyte-specific triple-KO mice (Epn1/2/3); albuminuria measurement; primary podocyte cell adhesion and spreading assays; Cdc42 activation assay; SRF and β1 integrin expression analysis\",\n      \"journal\": \"Journal of the American Society of Nephrology : JASN\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with defined cellular phenotype and pathway placement (Cdc42-SRF-β1 integrin), but single lab and EPN2 is studied only as part of a triple-KO\",\n      \"pmids\": [\"33051360\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"EPN2 (epsin2) is a direct target of miR-1224 in human endothelial cells; knockdown of EPN2 stimulates tube formation, while overexpression of EPN2 represses miR-1224-mediated stimulation of tube formation, establishing EPN2 as a suppressor of angiogenesis acting downstream of miR-1224.\",\n      \"method\": \"miR-1224 enforced expression and repression in HUVECs; EPN2 knockdown and overexpression; tube formation assay on Matrigel; direct target validation of miR-1224→EPN2\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — direct target validation with KD and OE rescue experiments in a single lab, multiple functional readouts but no in vitro reconstitution or structural data\",\n      \"pmids\": [\"28717225\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"The long transcript isoform of EPN2 mediates clathrin-dependent endocytosis-dependent degradation of the Wnt receptor frizzled 7 (FZD7); suppression of the EPN2 long transcript (via circSPARC-HNRNPC alternative splicing axis) impairs FZD7 degradation, sustaining Wnt/β-catenin activation and promoting ESCC progression. Expression of the EPN2 long transcript restores Wnt/β-catenin inhibition and suppresses ESCC malignancy.\",\n      \"method\": \"RNA pull-down, RIP, RAP, alternative splicing analysis, cell surface protein biotinylation; EPN2 long transcript overexpression in vitro and in vivo; circSPARC knockdown rescue experiments\",\n      \"journal\": \"Molecular cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal RNA-binding and functional methods in a single lab, with in vitro and in vivo validation; isoform-level specificity is well-supported but not yet replicated\",\n      \"pmids\": [\"42210380\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"EPN2 (epsin 2) is a clathrin-mediated endocytic adaptor that acts as a specialized cargo internalization factor: it is required (redundantly with EPN1) for Notch receptor activation during embryogenesis, mediates internalization and degradation of activated VEGFR2 to restrain angiogenesis, regulates FZD7 receptor turnover to limit Wnt/β-catenin signaling, and supports podocyte function through a Cdc42-SRF-β1 integrin axis—while being largely dispensable for bulk clathrin-mediated endocytosis.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"EPN2 (epsin 2) is a specialized clathrin-mediated endocytic adaptor that selectively controls the internalization and degradation of specific signaling receptors rather than supporting bulk endocytosis [#0]. Acting redundantly with EPN1, EPN2 is required for Notch signaling activation during embryogenesis, as combined Epn1/Epn2 loss recapitulates global Notch impairment and abolishes Notch target gene expression while leaving housekeeping clathrin-mediated endocytosis intact [#0]. In endothelial cells, EPN2 restrains angiogenesis by mediating internalization and degradation of activated VEGFR2, since epsin loss elevates VEGFR2 and produces aberrant angiogenesis that is rescued by reducing VEGFR2 gene dosage [#1]; consistent with this anti-angiogenic role, EPN2 acts as a suppressor of endothelial tube formation downstream of miR-1224 [#3]. EPN2 likewise limits Wnt/\\u03b2-catenin signaling: its long transcript isoform drives clathrin-dependent endocytic degradation of the Wnt receptor FZD7, and loss of this isoform sustains Wnt activation and promotes esophageal squamous cell carcinoma progression [#4]. In podocytes, epsins (Epn1/2/3) support cell adhesion and spreading upstream of a Cdc42\\u2013SRF\\u2013\\u03b21 integrin axis, with their loss causing albuminuria and foot process effacement [#2].\",\n  \"teleology\": [\n    {\n      \"year\": 2009,\n      \"claim\": \"Established that epsins are not generic endocytic machinery but specialized adaptors dedicated to receptor signaling, answering whether EPN1/EPN2 have a selective in vivo function.\",\n      \"evidence\": \"Epn1/Epn2 double-knockout mice with Notch target gene analysis and endocytosis assays in derived cells\",\n      \"pmids\": [\"19666558\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Does not resolve EPN2-specific contribution versus EPN1 redundancy\",\n        \"Direct biochemical link between EPN2 and Notch receptor/ligand internalization not shown\",\n        \"Molecular basis of cargo selectivity over bulk endocytosis unaddressed\"\n      ]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Identified a specific cargo for epsin-mediated degradation by showing epsins downregulate activated VEGFR2 to restrain angiogenesis, defining a mechanistic substrate beyond Notch.\",\n      \"evidence\": \"Endothelial-specific Epn1/Epn2 double-KO combined with Flk1 heterozygosity rescue; in vitro and in vivo angiogenesis assays\",\n      \"pmids\": [\"24311377\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"EPN2-specific role not separable from EPN1 in the double-KO\",\n        \"Direct EPN2-VEGFR2 physical interaction not biochemically defined\",\n        \"Mechanism distinguishing VEGFR2 from other endothelial receptors unknown\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Placed EPN2 within a regulatory circuit by showing it acts as a miR-1224-controlled suppressor of angiogenic tube formation, linking EPN2 expression level to endothelial behavior.\",\n      \"evidence\": \"miR-1224 modulation, EPN2 knockdown/overexpression, and tube formation assays in HUVECs with direct target validation\",\n      \"pmids\": [\"28717225\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Single-lab study without reconstitution or structural data\",\n        \"Whether anti-angiogenic effect operates through VEGFR2 degradation not tested here\",\n        \"In vivo relevance of the miR-1224\\u2192EPN2 axis not established\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Extended epsin function to cytoskeletal/adhesion signaling by placing epsins upstream of a Cdc42-SRF-\\u03b21 integrin axis required for podocyte function.\",\n      \"evidence\": \"Podocyte-specific Epn1/2/3 triple-KO mice; albuminuria, adhesion/spreading assays, Cdc42 activation and \\u03b21 integrin expression analysis\",\n      \"pmids\": [\"33051360\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"EPN2 studied only within a triple-KO, so its individual contribution is unresolved\",\n        \"Single lab; mechanism connecting epsins to Cdc42 activation not defined\",\n        \"Whether the role depends on receptor endocytosis is unclear\"\n      ]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Defined isoform-level specificity by showing the EPN2 long transcript drives clathrin-dependent FZD7 degradation to limit Wnt/\\u03b2-catenin signaling and tumor progression.\",\n      \"evidence\": \"RNA pull-down, RIP, RAP, splicing analysis, surface biotinylation, and EPN2 long-transcript overexpression in vitro and in vivo in ESCC models\",\n      \"pmids\": [\"42210380\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Single lab; isoform specificity not yet independently replicated\",\n        \"Direct EPN2\\u2013FZD7 interaction interface not mapped\",\n        \"Functional difference between EPN2 transcript isoforms mechanistically undefined\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How EPN2 selects specific signaling receptors (Notch, VEGFR2, FZD7) for internalization while sparing bulk endocytosis, and how EPN2 is distinguished from EPN1/EPN3 at the molecular level, remains unresolved.\",\n      \"evidence\": \"No direct mechanistic study isolating EPN2 cargo-recognition determinants in the available corpus\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No structural or biochemical map of EPN2 cargo recognition\",\n        \"EPN2-specific (non-redundant) functions not isolated from paralogs\",\n        \"Recruitment determinants distinguishing signaling cargo from bulk cargo unknown\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [1, 4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [1, 4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 1, 4]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 1, 4]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"EPN1\", \"VEGFR2\", \"FZD7\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}