{"gene":"ESAM","run_date":"2026-04-28T17:46:03","timeline":{"discoveries":[{"year":2004,"finding":"ESAM directly binds the multidomain adaptor protein MAGI-1 via a PDZ domain-mediated interaction at its C-terminal sequence, and recruits MAGI-1 to cell-cell contacts in endothelial cells; this interaction was identified by yeast two-hybrid screen, confirmed by pull-down and co-immunoisolation from transfected CHO cells.","method":"Yeast two-hybrid screen, pull-down assay, co-immunoprecipitation in CHO cells, colocalization in HUVECs and mouse endothelium","journal":"Experimental cell research","confidence":"High","confidence_rationale":"Tier 1-2 — yeast two-hybrid + pull-down + co-IP + colocalization, multiple orthogonal methods in single study","pmids":["15383320"],"is_preprint":false},{"year":2006,"finding":"ESAM at endothelial tight junctions is required for neutrophil transendothelial migration; ESAM-/- mice show ~50-70% reduction in neutrophil extravasation. Mechanistically, knockdown of ESAM in endothelial cells reduces levels of activated Rho GTPase, and ESAM-/- mice show reduced VEGF-induced vascular permeability. Platelet ESAM was excluded as the relevant source by platelet depletion experiments.","method":"ESAM knockout mouse, intravital microscopy, peritonitis inflammation model, siRNA knockdown of ESAM in endothelial cells, Rho activation assay, VEGF permeability assay, platelet depletion","journal":"The Journal of experimental medicine","confidence":"High","confidence_rationale":"Tier 2 — clean KO with defined cellular phenotype, multiple inflammation models, mechanistic follow-up with Rho activation assay, replicated across three models","pmids":["16818677"],"is_preprint":false},{"year":2009,"finding":"Following platelet activation, ESAM localizes to junctions between adjacent platelets and limits thrombus growth and stability. ESAM-/- mice show larger thrombi and more stable hemostasis; ESAM-/- platelets aggregate at lower agonist concentrations and resist disaggregation. The scaffold protein NHERF-1 was identified as an ESAM binding partner via PDZ domain array and confirmed to associate with ESAM in both resting and activated platelets.","method":"ESAM knockout mouse, tail transection hemostasis assay, laser injury cremaster arteriole model, platelet aggregation assay, calcium mobilization assay, alpha-granule secretion assay, PDZ domain array, co-immunoprecipitation","journal":"Journal of thrombosis and haemostasis : JTH","confidence":"High","confidence_rationale":"Tier 2 — KO mouse with multiple functional assays, PDZ array + co-IP for binding partner identification, in vivo and in vitro validation","pmids":["19740102"],"is_preprint":false},{"year":2019,"finding":"ESAM plays an essential, tissue-specific role in maintaining endothelial barrier integrity in the lung. Combined loss of ESAM and VE-cadherin (by antibody blockade or induced gene inactivation) causes rapid lethality, disruption of endothelial junctions, and massive blood coagulation specifically in the lung. Mechanistically, cytoplasmic signaling domains of ESAM and platelet ESAM were excluded as contributors; ESAM gene deletion alone enhanced vascular permeability in the lung but not in heart, skin, or brain.","method":"ESAM knockout mouse, induced VE-cadherin gene inactivation, anti-VE-cadherin antibody blockade, vascular permeability assays, ultrastructural analysis (electron microscopy), comparison with JAM-A-/- and PECAM-1-/- mice, platelet-specific rescue experiments","journal":"Arteriosclerosis, thrombosis, and vascular biology","confidence":"High","confidence_rationale":"Tier 2 — multiple KO combinations with rigorous controls, ultrastructural validation, mechanistic exclusions tested directly","pmids":["31826650"],"is_preprint":false},{"year":2023,"finding":"Bi-allelic loss-of-function variants in ESAM cause impaired in vitro tubulogenesis of endothelial colony-forming cells, recapitulating vascular network formation defects; loss of ESAM expression was confirmed in capillary endothelial cells of damaged brain tissue from affected individuals, establishing ESAM as essential for brain endothelial function and blood-brain barrier integrity.","method":"Human genetics (homozygous LOF variants in 13 individuals from 8 families), in vitro tubulogenesis assay of endothelial colony-forming cells, immunostaining of patient brain tissue","journal":"American journal of human genetics","confidence":"Medium","confidence_rationale":"Tier 2 — human LOF variants with in vitro functional validation and tissue confirmation, but single study","pmids":["36996813"],"is_preprint":false},{"year":2012,"finding":"ESAM is functionally required for hematopoietic stem cell (HSC) re-establishment of hematopoiesis after bone marrow injury; ESAM-/- mice show severe and prolonged bone marrow suppression after 5-fluorouracil treatment. ESAM expression level mirrors HSC activation status (quiescence vs. proliferation), and ESAM-hi HSCs preferentially localize near vascular endothelium in bone marrow after injury. NF-κB and topoisomerase II levels correlate with ESAM upregulation.","method":"ESAM knockout mouse, 5-fluorouracil bone marrow injury model, flow cytometry, immunohistochemistry, cell cycle analysis","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 — KO mouse with defined functional phenotype and localization data, single lab","pmids":["22649198"],"is_preprint":false},{"year":2020,"finding":"miR-7 reduces ESAM expression in breast cancer stem cells by directly targeting the 3' UTR of RELA (NF-κB p65), thereby suppressing RELA-driven transcription of ESAM; this was demonstrated by dual-luciferase reporter assay and chromatin immunoprecipitation-PCR.","method":"Dual-luciferase reporter assay, chromatin immunoprecipitation-PCR, miR-7 mimic overexpression, xenograft mouse model","journal":"Molecular therapy oncolytics","confidence":"Medium","confidence_rationale":"Tier 2 — luciferase reporter + ChIP-PCR with functional in vivo validation, single lab","pmids":["32637582"],"is_preprint":false}],"current_model":"ESAM is an immunoglobulin-like transmembrane protein localized at endothelial tight junctions and on platelets, where it maintains vascular barrier integrity (particularly in the lung, cooperatively with VE-cadherin), supports neutrophil transendothelial migration by activating Rho GTPase, limits platelet thrombus growth via contact-dependent signaling through its PDZ-binding domain (interacting with MAGI-1 at endothelial junctions and NHERF-1 in platelets), and is required for hematopoietic stem cell reactivation after bone marrow injury; its expression is transcriptionally regulated by NF-κB/RELA."},"narrative":{"teleology":[{"year":2004,"claim":"Identifying ESAM's first cytoplasmic binding partner established that it signals through PDZ-domain scaffolding at cell-cell contacts rather than acting solely as an adhesion molecule.","evidence":"Yeast two-hybrid screen, pull-down, co-IP in CHO cells, and colocalization in HUVECs and mouse endothelium","pmids":["15383320"],"confidence":"High","gaps":["Functional consequence of ESAM–MAGI-1 interaction for junctional signaling was not tested","Whether ESAM engages other PDZ-domain adaptors in non-endothelial cells was unknown"]},{"year":2006,"claim":"Demonstrating that ESAM-null mice have severely impaired neutrophil extravasation and reduced Rho activation resolved whether ESAM is required for leukocyte transendothelial migration and identified a downstream signaling axis.","evidence":"ESAM knockout mouse with intravital microscopy, peritonitis models, endothelial siRNA knockdown, Rho-GTP pull-down, VEGF permeability assay, and platelet depletion controls","pmids":["16818677"],"confidence":"High","gaps":["How ESAM triggers Rho GTPase activation (direct GEF recruitment vs. indirect mechanism) was not resolved","Whether MAGI-1 mediates the Rho signaling was untested"]},{"year":2009,"claim":"Showing that ESAM limits platelet thrombus growth and identifying NHERF-1 as its platelet-specific PDZ partner extended ESAM's function from endothelial junctions to a contact-dependent negative regulator of platelet aggregation.","evidence":"ESAM knockout mouse with tail transection, laser-injury thrombosis, platelet aggregometry, PDZ domain array, and co-IP from resting and activated platelets","pmids":["19740102"],"confidence":"High","gaps":["Signaling pathway downstream of ESAM–NHERF-1 in platelets was not defined","Whether ESAM engages homophilic or heterophilic adhesion between platelets was not determined"]},{"year":2012,"claim":"Finding that ESAM-null mice fail to recover hematopoiesis after bone marrow injury revealed an unexpected role for ESAM in hematopoietic stem cell reactivation, linking it to NF-κB-correlated activation programs.","evidence":"ESAM knockout mouse, 5-fluorouracil injury model, flow cytometry, immunohistochemistry, and cell cycle analysis","pmids":["22649198"],"confidence":"Medium","gaps":["Whether ESAM acts cell-autonomously in HSCs or through their endothelial niche was not distinguished","Causal relationship between NF-κB and ESAM upregulation in HSCs was correlative"]},{"year":2019,"claim":"Demonstrating that combined loss of ESAM and VE-cadherin causes lethal lung-specific vascular failure established ESAM as a functionally non-redundant component of lung endothelial barrier integrity and defined tissue-specific hierarchy among junctional molecules.","evidence":"ESAM knockout combined with induced VE-cadherin inactivation or antibody blockade, permeability assays in multiple organs, electron microscopy, and platelet-specific rescue experiments","pmids":["31826650"],"confidence":"High","gaps":["Molecular basis for lung specificity (unique junctional composition or hemodynamic factors) was not resolved","Whether ESAM's extracellular domain mediates homophilic adhesion at lung endothelial junctions remains unclear"]},{"year":2020,"claim":"Identifying RELA/NF-κB as a direct transcriptional activator of ESAM via ChIP-PCR resolved the upstream regulatory input controlling ESAM expression.","evidence":"Dual-luciferase reporter assay, ChIP-PCR for RELA binding at ESAM promoter, miR-7 overexpression in breast cancer stem cells, xenograft model","pmids":["32637582"],"confidence":"Medium","gaps":["Whether NF-κB drives ESAM transcription in endothelial cells and HSCs (not just cancer cells) was not tested","Other transcription factors regulating ESAM remain uncharacterized"]},{"year":2023,"claim":"Identification of bi-allelic ESAM loss-of-function variants in humans with neurovascular disease and recapitulation of tubulogenesis defects in patient-derived cells translated the mouse vascular phenotype to a human Mendelian disorder.","evidence":"Homozygous LOF variants in 13 individuals from 8 families, in vitro tubulogenesis of endothelial colony-forming cells, immunostaining of patient brain tissue","pmids":["36996813"],"confidence":"Medium","gaps":["Full clinical spectrum and natural history of human ESAM deficiency are incompletely defined","Whether blood-brain barrier defects result from loss of ESAM adhesion, signaling, or both is unknown","Animal model rescue experiments to confirm causality of specific variants were not performed"]},{"year":null,"claim":"The molecular mechanism by which ESAM activates Rho GTPase, the identity of its extracellular binding partner(s), and the structural basis for its tissue-specific barrier function remain unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No GEF or direct Rho activator downstream of ESAM has been identified","Whether ESAM mediates homophilic or heterophilic adhesion is not resolved","No structural model of the ESAM extracellular or cytoplasmic domains exists","Cell-autonomous versus niche-mediated role in HSC reactivation is untested"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[1,2]},{"term_id":"GO:0098631","term_label":"cell adhesion mediator activity","supporting_discovery_ids":[1,3]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,1,2,3]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[1]},{"term_id":"R-HSA-1500931","term_label":"Cell-Cell communication","supporting_discovery_ids":[0,1,3]},{"term_id":"R-HSA-109582","term_label":"Hemostasis","supporting_discovery_ids":[2]}],"complexes":[],"partners":["MAGI1","SLC9A3R1","CDH5","RELA"],"other_free_text":[]},"mechanistic_narrative":"ESAM is an immunoglobulin-superfamily transmembrane protein that functions at endothelial cell-cell junctions and on activated platelets to regulate vascular barrier integrity, leukocyte transendothelial migration, and thrombus stability. At endothelial junctions, ESAM recruits the PDZ-domain adaptor MAGI-1, activates Rho GTPase to facilitate neutrophil extravasation, and cooperates with VE-cadherin to maintain lung-specific vascular barrier function—combined loss of ESAM and VE-cadherin causes lethal pulmonary vascular disruption [PMID:15383320, PMID:16818677, PMID:31826650]. On platelets, ESAM localizes to contact sites between adjacent platelets and limits thrombus growth through its PDZ-binding domain and its partner NHERF-1 [PMID:19740102]. Bi-allelic loss-of-function ESAM variants in humans cause defective endothelial tubulogenesis and loss of blood-brain barrier integrity, establishing ESAM as a disease gene for a neurovascular disorder [PMID:36996813]."},"prefetch_data":{"uniprot":{"accession":"Q96AP7","full_name":"Endothelial cell-selective adhesion molecule","aliases":[],"length_aa":390,"mass_kda":41.2,"function":"Can mediate aggregation most likely through a homophilic molecular interaction","subcellular_location":"Cell junction, adherens junction; Cell junction, tight junction; Cell membrane","url":"https://www.uniprot.org/uniprotkb/Q96AP7/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ESAM","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/ESAM","total_profiled":1310},"omim":[{"mim_id":"620371","title":"NEURODEVELOPMENTAL DISORDER WITH INTRACRANIAL HEMORRHAGE, SEIZURES, AND SPASTICITY; NEDIHSS","url":"https://www.omim.org/entry/620371"},{"mim_id":"614281","title":"ENDOTHELIAL CELL ADHESION MOLECULE; ESAM","url":"https://www.omim.org/entry/614281"},{"mim_id":"608351","title":"IMMUNOGLOBULIN SUPERFAMILY, MEMBER 11; IGSF11","url":"https://www.omim.org/entry/608351"},{"mim_id":"181500","title":"SCHIZOPHRENIA; SCZD","url":"https://www.omim.org/entry/181500"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Cell Junctions","reliability":"Approved"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/ESAM"},"hgnc":{"alias_symbol":["W117m"],"prev_symbol":[]},"alphafold":{"accession":"Q96AP7","domains":[{"cath_id":"2.60.40.10","chopping":"31-151","consensus_level":"high","plddt":90.6892,"start":31,"end":151},{"cath_id":"2.60.40.10","chopping":"158-240","consensus_level":"high","plddt":96.7254,"start":158,"end":240}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96AP7","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q96AP7-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q96AP7-F1-predicted_aligned_error_v6.png","plddt_mean":77.56},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ESAM","jax_strain_url":"https://www.jax.org/strain/search?query=ESAM"},"sequence":{"accession":"Q96AP7","fasta_url":"https://rest.uniprot.org/uniprotkb/Q96AP7.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q96AP7/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96AP7"}},"corpus_meta":[{"pmid":"16818677","id":"PMC_16818677","title":"ESAM supports neutrophil extravasation, activation of Rho, and VEGF-induced vascular permeability.","date":"2006","source":"The Journal of experimental medicine","url":"https://pubmed.ncbi.nlm.nih.gov/16818677","citation_count":188,"is_preprint":false},{"pmid":"12851705","id":"PMC_12851705","title":"IGSF11 gene, frequently up-regulated in intestinal-type gastric cancer, encodes adhesion molecule homologous to CXADR, FLJ22415 and ESAM.","date":"2003","source":"International journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/12851705","citation_count":88,"is_preprint":false},{"pmid":"15383320","id":"PMC_15383320","title":"Endothelial adhesion molecule ESAM binds directly to the multidomain adaptor MAGI-1 and recruits it to cell contacts.","date":"2004","source":"Experimental cell research","url":"https://pubmed.ncbi.nlm.nih.gov/15383320","citation_count":72,"is_preprint":false},{"pmid":"19096010","id":"PMC_19096010","title":"The endothelial antigen ESAM marks primitive hematopoietic progenitors throughout life in mice.","date":"2008","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/19096010","citation_count":69,"is_preprint":false},{"pmid":"19740102","id":"PMC_19740102","title":"Endothelial cell specific adhesion molecule (ESAM) localizes to platelet-platelet contacts and regulates thrombus formation in vivo.","date":"2009","source":"Journal of thrombosis and haemostasis : JTH","url":"https://pubmed.ncbi.nlm.nih.gov/19740102","citation_count":52,"is_preprint":false},{"pmid":"31826650","id":"PMC_31826650","title":"Interference With ESAM (Endothelial Cell-Selective Adhesion Molecule) Plus Vascular Endothelial-Cadherin Causes Immediate Lethality and Lung-Specific Blood Coagulation.","date":"2019","source":"Arteriosclerosis, thrombosis, and vascular biology","url":"https://pubmed.ncbi.nlm.nih.gov/31826650","citation_count":35,"is_preprint":false},{"pmid":"24204843","id":"PMC_24204843","title":"Transcriptional reprogramming of CD11b+Esam(hi) dendritic cell identity and function by loss of Runx3.","date":"2013","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/24204843","citation_count":30,"is_preprint":false},{"pmid":"32637582","id":"PMC_32637582","title":"miR-7 Reduces Breast Cancer Stem Cell Metastasis via Inhibiting RELA to Decrease ESAM Expression.","date":"2020","source":"Molecular therapy oncolytics","url":"https://pubmed.ncbi.nlm.nih.gov/32637582","citation_count":27,"is_preprint":false},{"pmid":"22649198","id":"PMC_22649198","title":"The endothelial antigen ESAM monitors hematopoietic stem cell status between quiescence and self-renewal.","date":"2012","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/22649198","citation_count":27,"is_preprint":false},{"pmid":"26774386","id":"PMC_26774386","title":"ESAM is a novel human hematopoietic stem cell marker associated with a subset of human leukemias.","date":"2016","source":"Experimental hematology","url":"https://pubmed.ncbi.nlm.nih.gov/26774386","citation_count":21,"is_preprint":false},{"pmid":"36996813","id":"PMC_36996813","title":"Bi-allelic variants in the ESAM tight-junction gene cause a neurodevelopmental disorder associated with fetal intracranial hemorrhage.","date":"2023","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/36996813","citation_count":15,"is_preprint":false},{"pmid":"28630070","id":"PMC_28630070","title":"Regulation of Type III Secretion of Translocon and Effector Proteins by the EsaB/EsaL/EsaM Complex in Edwardsiella tarda.","date":"2017","source":"Infection and immunity","url":"https://pubmed.ncbi.nlm.nih.gov/28630070","citation_count":14,"is_preprint":false},{"pmid":"35357005","id":"PMC_35357005","title":"Flt3L, LIF, and IL-10 combination promotes the selective in vitro development of ESAMlow cDC2B from murine bone marrow.","date":"2022","source":"European journal of immunology","url":"https://pubmed.ncbi.nlm.nih.gov/35357005","citation_count":7,"is_preprint":false},{"pmid":"35457187","id":"PMC_35457187","title":"3D Visualization of Human Blood Vascular Networks Using Single-Domain Antibodies Directed against Endothelial Cell-Selective Adhesion Molecule (ESAM).","date":"2022","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/35457187","citation_count":3,"is_preprint":false},{"pmid":"39414991","id":"PMC_39414991","title":"Novel homozygous ESAM variants in two families with perinatal strokes showing variable neuroradiologic and clinical findings.","date":"2024","source":"Journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/39414991","citation_count":3,"is_preprint":false},{"pmid":"36058862","id":"PMC_36058862","title":"[Exploring new molecules that regulate hematopoietic stem cells and early stages of lymphoid hematopoiesis: the functional significance of ESAM and SATB1].","date":"2022","source":"[Rinsho ketsueki] The Japanese journal of clinical hematology","url":"https://pubmed.ncbi.nlm.nih.gov/36058862","citation_count":0,"is_preprint":false},{"pmid":"38008937","id":"PMC_38008937","title":"Extraretinal Fibrovascular Proliferation in a Neonate Possibly Associated with an ESAM Gene Variant.","date":"2023","source":"Turkish journal of ophthalmology","url":"https://pubmed.ncbi.nlm.nih.gov/38008937","citation_count":0,"is_preprint":false},{"pmid":"41525715","id":"PMC_41525715","title":"ESAM Loss of Function and Congenital Neurovascular Injury: Strengthening the Case for a Recognizable Clinical Phenotype.","date":"2026","source":"Clinical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/41525715","citation_count":0,"is_preprint":false},{"pmid":"26062667","id":"PMC_26062667","title":"[Role of endothelial antigen ESAM in activated hematopoietic stem cells].","date":"2015","source":"[Rinsho ketsueki] The Japanese journal of clinical hematology","url":"https://pubmed.ncbi.nlm.nih.gov/26062667","citation_count":0,"is_preprint":false},{"pmid":"26329529","id":"PMC_26329529","title":"ESAM predicts cardiovascular mortality in diabetic hemodialysis patients.","date":"2015","source":"Biomarkers : biochemical indicators of exposure, response, and susceptibility to chemicals","url":"https://pubmed.ncbi.nlm.nih.gov/26329529","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.10.19.683343","title":"Transcriptomic profiling of the middle temporal gyrus reveals differential glial/neuronal dysregulation across Alzheimer’s disease and aging","date":"2025-10-20","source":"bioRxiv","url":"https://doi.org/10.1101/2025.10.19.683343","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.02.15.638465","title":"Single Cell Proteomics Reveals Novel Cell Phenotypes in Marfan Mouse Aneurysm","date":"2025-02-23","source":"bioRxiv","url":"https://doi.org/10.1101/2025.02.15.638465","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.05.28.596337","title":"Computational identification of surface markers for isolating distinct subpopulations from heterogeneous cancer cell populations","date":"2024-06-02","source":"bioRxiv","url":"https://doi.org/10.1101/2024.05.28.596337","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":13570,"output_tokens":2037,"usd":0.035632},"stage2":{"model":"claude-opus-4-6","input_tokens":5298,"output_tokens":2204,"usd":0.122385},"total_usd":0.158017,"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\": 2004,\n      \"finding\": \"ESAM directly binds the multidomain adaptor protein MAGI-1 via a PDZ domain-mediated interaction at its C-terminal sequence, and recruits MAGI-1 to cell-cell contacts in endothelial cells; this interaction was identified by yeast two-hybrid screen, confirmed by pull-down and co-immunoisolation from transfected CHO cells.\",\n      \"method\": \"Yeast two-hybrid screen, pull-down assay, co-immunoprecipitation in CHO cells, colocalization in HUVECs and mouse endothelium\",\n      \"journal\": \"Experimental cell research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — yeast two-hybrid + pull-down + co-IP + colocalization, multiple orthogonal methods in single study\",\n      \"pmids\": [\"15383320\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"ESAM at endothelial tight junctions is required for neutrophil transendothelial migration; ESAM-/- mice show ~50-70% reduction in neutrophil extravasation. Mechanistically, knockdown of ESAM in endothelial cells reduces levels of activated Rho GTPase, and ESAM-/- mice show reduced VEGF-induced vascular permeability. Platelet ESAM was excluded as the relevant source by platelet depletion experiments.\",\n      \"method\": \"ESAM knockout mouse, intravital microscopy, peritonitis inflammation model, siRNA knockdown of ESAM in endothelial cells, Rho activation assay, VEGF permeability assay, platelet depletion\",\n      \"journal\": \"The Journal of experimental medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean KO with defined cellular phenotype, multiple inflammation models, mechanistic follow-up with Rho activation assay, replicated across three models\",\n      \"pmids\": [\"16818677\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Following platelet activation, ESAM localizes to junctions between adjacent platelets and limits thrombus growth and stability. ESAM-/- mice show larger thrombi and more stable hemostasis; ESAM-/- platelets aggregate at lower agonist concentrations and resist disaggregation. The scaffold protein NHERF-1 was identified as an ESAM binding partner via PDZ domain array and confirmed to associate with ESAM in both resting and activated platelets.\",\n      \"method\": \"ESAM knockout mouse, tail transection hemostasis assay, laser injury cremaster arteriole model, platelet aggregation assay, calcium mobilization assay, alpha-granule secretion assay, PDZ domain array, co-immunoprecipitation\",\n      \"journal\": \"Journal of thrombosis and haemostasis : JTH\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — KO mouse with multiple functional assays, PDZ array + co-IP for binding partner identification, in vivo and in vitro validation\",\n      \"pmids\": [\"19740102\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"ESAM plays an essential, tissue-specific role in maintaining endothelial barrier integrity in the lung. Combined loss of ESAM and VE-cadherin (by antibody blockade or induced gene inactivation) causes rapid lethality, disruption of endothelial junctions, and massive blood coagulation specifically in the lung. Mechanistically, cytoplasmic signaling domains of ESAM and platelet ESAM were excluded as contributors; ESAM gene deletion alone enhanced vascular permeability in the lung but not in heart, skin, or brain.\",\n      \"method\": \"ESAM knockout mouse, induced VE-cadherin gene inactivation, anti-VE-cadherin antibody blockade, vascular permeability assays, ultrastructural analysis (electron microscopy), comparison with JAM-A-/- and PECAM-1-/- mice, platelet-specific rescue experiments\",\n      \"journal\": \"Arteriosclerosis, thrombosis, and vascular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple KO combinations with rigorous controls, ultrastructural validation, mechanistic exclusions tested directly\",\n      \"pmids\": [\"31826650\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Bi-allelic loss-of-function variants in ESAM cause impaired in vitro tubulogenesis of endothelial colony-forming cells, recapitulating vascular network formation defects; loss of ESAM expression was confirmed in capillary endothelial cells of damaged brain tissue from affected individuals, establishing ESAM as essential for brain endothelial function and blood-brain barrier integrity.\",\n      \"method\": \"Human genetics (homozygous LOF variants in 13 individuals from 8 families), in vitro tubulogenesis assay of endothelial colony-forming cells, immunostaining of patient brain tissue\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — human LOF variants with in vitro functional validation and tissue confirmation, but single study\",\n      \"pmids\": [\"36996813\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"ESAM is functionally required for hematopoietic stem cell (HSC) re-establishment of hematopoiesis after bone marrow injury; ESAM-/- mice show severe and prolonged bone marrow suppression after 5-fluorouracil treatment. ESAM expression level mirrors HSC activation status (quiescence vs. proliferation), and ESAM-hi HSCs preferentially localize near vascular endothelium in bone marrow after injury. NF-κB and topoisomerase II levels correlate with ESAM upregulation.\",\n      \"method\": \"ESAM knockout mouse, 5-fluorouracil bone marrow injury model, flow cytometry, immunohistochemistry, cell cycle analysis\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — KO mouse with defined functional phenotype and localization data, single lab\",\n      \"pmids\": [\"22649198\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"miR-7 reduces ESAM expression in breast cancer stem cells by directly targeting the 3' UTR of RELA (NF-κB p65), thereby suppressing RELA-driven transcription of ESAM; this was demonstrated by dual-luciferase reporter assay and chromatin immunoprecipitation-PCR.\",\n      \"method\": \"Dual-luciferase reporter assay, chromatin immunoprecipitation-PCR, miR-7 mimic overexpression, xenograft mouse model\",\n      \"journal\": \"Molecular therapy oncolytics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — luciferase reporter + ChIP-PCR with functional in vivo validation, single lab\",\n      \"pmids\": [\"32637582\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ESAM is an immunoglobulin-like transmembrane protein localized at endothelial tight junctions and on platelets, where it maintains vascular barrier integrity (particularly in the lung, cooperatively with VE-cadherin), supports neutrophil transendothelial migration by activating Rho GTPase, limits platelet thrombus growth via contact-dependent signaling through its PDZ-binding domain (interacting with MAGI-1 at endothelial junctions and NHERF-1 in platelets), and is required for hematopoietic stem cell reactivation after bone marrow injury; its expression is transcriptionally regulated by NF-κB/RELA.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"ESAM is an immunoglobulin-superfamily transmembrane protein that functions at endothelial cell-cell junctions and on activated platelets to regulate vascular barrier integrity, leukocyte transendothelial migration, and thrombus stability. At endothelial junctions, ESAM recruits the PDZ-domain adaptor MAGI-1, activates Rho GTPase to facilitate neutrophil extravasation, and cooperates with VE-cadherin to maintain lung-specific vascular barrier function—combined loss of ESAM and VE-cadherin causes lethal pulmonary vascular disruption [PMID:15383320, PMID:16818677, PMID:31826650]. On platelets, ESAM localizes to contact sites between adjacent platelets and limits thrombus growth through its PDZ-binding domain and its partner NHERF-1 [PMID:19740102]. Bi-allelic loss-of-function ESAM variants in humans cause defective endothelial tubulogenesis and loss of blood-brain barrier integrity, establishing ESAM as a disease gene for a neurovascular disorder [PMID:36996813].\",\n  \"teleology\": [\n    {\n      \"year\": 2004,\n      \"claim\": \"Identifying ESAM's first cytoplasmic binding partner established that it signals through PDZ-domain scaffolding at cell-cell contacts rather than acting solely as an adhesion molecule.\",\n      \"evidence\": \"Yeast two-hybrid screen, pull-down, co-IP in CHO cells, and colocalization in HUVECs and mouse endothelium\",\n      \"pmids\": [\"15383320\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Functional consequence of ESAM–MAGI-1 interaction for junctional signaling was not tested\",\n        \"Whether ESAM engages other PDZ-domain adaptors in non-endothelial cells was unknown\"\n      ]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Demonstrating that ESAM-null mice have severely impaired neutrophil extravasation and reduced Rho activation resolved whether ESAM is required for leukocyte transendothelial migration and identified a downstream signaling axis.\",\n      \"evidence\": \"ESAM knockout mouse with intravital microscopy, peritonitis models, endothelial siRNA knockdown, Rho-GTP pull-down, VEGF permeability assay, and platelet depletion controls\",\n      \"pmids\": [\"16818677\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"How ESAM triggers Rho GTPase activation (direct GEF recruitment vs. indirect mechanism) was not resolved\",\n        \"Whether MAGI-1 mediates the Rho signaling was untested\"\n      ]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Showing that ESAM limits platelet thrombus growth and identifying NHERF-1 as its platelet-specific PDZ partner extended ESAM's function from endothelial junctions to a contact-dependent negative regulator of platelet aggregation.\",\n      \"evidence\": \"ESAM knockout mouse with tail transection, laser-injury thrombosis, platelet aggregometry, PDZ domain array, and co-IP from resting and activated platelets\",\n      \"pmids\": [\"19740102\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Signaling pathway downstream of ESAM–NHERF-1 in platelets was not defined\",\n        \"Whether ESAM engages homophilic or heterophilic adhesion between platelets was not determined\"\n      ]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Finding that ESAM-null mice fail to recover hematopoiesis after bone marrow injury revealed an unexpected role for ESAM in hematopoietic stem cell reactivation, linking it to NF-κB-correlated activation programs.\",\n      \"evidence\": \"ESAM knockout mouse, 5-fluorouracil injury model, flow cytometry, immunohistochemistry, and cell cycle analysis\",\n      \"pmids\": [\"22649198\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether ESAM acts cell-autonomously in HSCs or through their endothelial niche was not distinguished\",\n        \"Causal relationship between NF-κB and ESAM upregulation in HSCs was correlative\"\n      ]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Demonstrating that combined loss of ESAM and VE-cadherin causes lethal lung-specific vascular failure established ESAM as a functionally non-redundant component of lung endothelial barrier integrity and defined tissue-specific hierarchy among junctional molecules.\",\n      \"evidence\": \"ESAM knockout combined with induced VE-cadherin inactivation or antibody blockade, permeability assays in multiple organs, electron microscopy, and platelet-specific rescue experiments\",\n      \"pmids\": [\"31826650\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Molecular basis for lung specificity (unique junctional composition or hemodynamic factors) was not resolved\",\n        \"Whether ESAM's extracellular domain mediates homophilic adhesion at lung endothelial junctions remains unclear\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Identifying RELA/NF-κB as a direct transcriptional activator of ESAM via ChIP-PCR resolved the upstream regulatory input controlling ESAM expression.\",\n      \"evidence\": \"Dual-luciferase reporter assay, ChIP-PCR for RELA binding at ESAM promoter, miR-7 overexpression in breast cancer stem cells, xenograft model\",\n      \"pmids\": [\"32637582\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether NF-κB drives ESAM transcription in endothelial cells and HSCs (not just cancer cells) was not tested\",\n        \"Other transcription factors regulating ESAM remain uncharacterized\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identification of bi-allelic ESAM loss-of-function variants in humans with neurovascular disease and recapitulation of tubulogenesis defects in patient-derived cells translated the mouse vascular phenotype to a human Mendelian disorder.\",\n      \"evidence\": \"Homozygous LOF variants in 13 individuals from 8 families, in vitro tubulogenesis of endothelial colony-forming cells, immunostaining of patient brain tissue\",\n      \"pmids\": [\"36996813\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Full clinical spectrum and natural history of human ESAM deficiency are incompletely defined\",\n        \"Whether blood-brain barrier defects result from loss of ESAM adhesion, signaling, or both is unknown\",\n        \"Animal model rescue experiments to confirm causality of specific variants were not performed\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The molecular mechanism by which ESAM activates Rho GTPase, the identity of its extracellular binding partner(s), and the structural basis for its tissue-specific barrier function remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No GEF or direct Rho activator downstream of ESAM has been identified\",\n        \"Whether ESAM mediates homophilic or heterophilic adhesion is not resolved\",\n        \"No structural model of the ESAM extracellular or cytoplasmic domains exists\",\n        \"Cell-autonomous versus niche-mediated role in HSC reactivation is untested\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [1, 2]},\n      {\"term_id\": \"GO:0098631\", \"supporting_discovery_ids\": [1, 3]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 1, 2, 3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"R-HSA-1500931\", \"supporting_discovery_ids\": [0, 1, 3]},\n      {\"term_id\": \"R-HSA-109582\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"MAGI1\",\n      \"SLC9A3R1\",\n      \"CDH5\",\n      \"RELA\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}