{"gene":"CLEC14A","run_date":"2026-04-28T17:28:52","timeline":{"discoveries":[{"year":2010,"finding":"CLEC14A mediates endothelial cell-cell adhesion through its C-type lectin-like domain (CTLD), as demonstrated by deletion mutant analysis; knockdown in endothelial cells suppressed cell migratory activity, filopodial protrusion, and tube formation.","method":"Deletion mutant analysis, siRNA knockdown, cell migration and tube formation assays","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 — clean KD with defined cellular phenotype and domain mapping, single lab","pmids":["21095181"],"is_preprint":false},{"year":2011,"finding":"CLEC14A is a tumor endothelial marker that induces filopodia, facilitates endothelial migration and tube formation, and promotes vascular development in zebrafish; anti-CLEC14A antisera inhibited cell migration and tube formation.","method":"Overexpression, antisera inhibition assays, zebrafish developmental assay, immunohistochemistry","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 — multiple functional assays in vitro and in vivo, single lab","pmids":["21706054"],"is_preprint":false},{"year":2013,"finding":"The C-type lectin-like domain (CTLD) of CLEC14A is a key functional domain mediating cell-cell contact; antibodies targeting CTLD blocked endothelial cell migration, tube formation, and CTLD-CTLD interactions, and cross-linking downregulated CLEC14A surface expression.","method":"Phage display antibody selection, functional blocking assays, cell migration and tube formation assays","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 — domain-specific antibody blocking with multiple functional readouts, single lab","pmids":["23644659"],"is_preprint":false},{"year":2015,"finding":"CLEC14A binds directly to the extracellular matrix protein Multimerin-2 (MMRN2) via its extracellular region, as confirmed by pull-down and co-immunoprecipitation; this CLEC14A-MMRN2 interaction promotes sprouting angiogenesis and tumor growth, and blocking it with monoclonal antibody C4 inhibited endothelial sprouting and tumor growth in vivo.","method":"Pull-down, co-immunoprecipitation, monoclonal antibody blocking, aortic ring assay, in vivo tumor model","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 1–2 — reciprocal Co-IP, antibody blocking, and in vivo functional validation","pmids":["25745997"],"is_preprint":false},{"year":2016,"finding":"CLEC14A ectodomain is cleaved (shed) by rhomboid-like protease RHBDL2, but not RHBDL1 or RHBDL3; site-directed mutagenesis identified the precise cleavage site; the shed ectodomain inhibits sprouting angiogenesis and binds to sprouting endothelial tip cells.","method":"Site-directed mutagenesis, siRNA knockdown of CLEC14A and RHBDL2, in vitro sprouting assays, in vivo sponge implant model, recombinant protein addition","journal":"FASEB journal","confidence":"High","confidence_rationale":"Tier 1 — mutagenesis identifying cleavage site, siRNA specificity validation, in vitro and in vivo functional assays","pmids":["26939791"],"is_preprint":false},{"year":2016,"finding":"CLEC14A forms a complex with VEGFR-3 in endothelial cells; CLEC14A knockout leads to reduced VEGFR-3 expression with concomitant increases in VEGFR-2 expression and downstream signaling, establishing CLEC14A as a regulator of VEGFR-2/VEGFR-3 balance in vascular homeostasis.","method":"Co-immunoprecipitation (complex formation), CLEC14A knockout mouse, Western blotting, in vivo vascular phenotype analysis, VEGFR-2 blockade epistasis","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 2 — Co-IP for complex, KO mouse with defined molecular and phenotypic readouts, epistasis with VEGFR-2 blockade","pmids":["27991863"],"is_preprint":false},{"year":2017,"finding":"CLEC14A, CD93, and CD248 all directly bind to Multimerin-2 (MMRN2); binding is dependent on a long-loop region in the C-type lectin domain and is abrogated by mutation within this domain; CLEC14A and CD93 bind the same non-glycosylated coiled-coil region of MMRN2, whereas CD248 binds a distinct non-competing region; CLEC14A and CD248 can simultaneously bind MMRN2, occurring at the endothelial-pericyte interface in human pancreatic cancer.","method":"Direct binding assays, mutagenesis (long-loop region), recombinant protein competition assays, co-localization in human tissue","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 1 — direct binding with mutagenesis, domain mapping, and functional blocking peptide validated in vitro and in vivo","pmids":["28671670"],"is_preprint":false},{"year":2017,"finding":"HSP70-1A interacts with CLEC14A specifically at amino acids 43–69 of the CTLD; this interaction mediates HSP70-1A-induced ERK phosphorylation and endothelial tube formation; competitive blocking of this region inhibits HSP70-1A-induced angiogenesis.","method":"Proteomic isolation, co-immunoprecipitation, in vitro binding assays, competitive blocking experiments, ERK phosphorylation assay, tube formation assay","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 — Co-IP and in vitro binding with domain mapping and functional blocking, single lab","pmids":["28878328"],"is_preprint":false},{"year":2018,"finding":"The CLEC14A C-type lectin-like domain (CTLD) mediates endothelial cell-cell contact in angiogenesis; an antibody targeting CTLD directly inhibits this cell-cell contact and simultaneously downregulates CLEC14A surface expression, suppressing VEGF-dependent and tumor angiogenesis in vitro and in vivo.","method":"CDR grafting antibody generation, cell-cell contact assays, in vitro tube formation, in vivo tumor xenograft models","journal":"Molecular oncology","confidence":"Medium","confidence_rationale":"Tier 2 — antibody-based mechanistic dissection with multiple in vitro and in vivo models, single lab","pmids":["29316206"],"is_preprint":false},{"year":2019,"finding":"In zebrafish, clec14a genetically interacts with ETS transcription factor Etv2 and with Vegfa signaling in vasculogenesis and angiogenesis; partial knockdown of Etv2 or Vegfaa shows synergistic inhibition with clec14a mutation, placing Clec14a in the same pathway as Etv2 and Vegf signaling.","method":"TALEN genome editing (zebrafish clec14a mutant), morpholino knockdown, genetic epistasis, vascular phenotype analysis","journal":"BMC developmental biology","confidence":"Medium","confidence_rationale":"Tier 2 — epistasis via double mutant/knockdown combinations in zebrafish, single lab","pmids":["30953479"],"is_preprint":false},{"year":2020,"finding":"The C-type lectin domain of CLEC14A binds heparin in a 1:1 ratio with nanomolar affinity; molecular modeling and mutagenesis mapped the heparin-binding site within the CTLD; CLEC14A also physically interacts with endothelial heparan sulfate and chondroitin sulfate E but not neutral or sialylated oligosaccharides.","method":"Heparin-affinity chromatography (LPHAMS proteomics), molecular modeling, site-directed mutagenesis, binding affinity measurements","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — in vitro binding with affinity quantification, mutagenesis-based site mapping","pmids":["31964714"],"is_preprint":false},{"year":2020,"finding":"CLEC14A deficiency increases BBB permeability by downregulating tight junctional proteins and activating VEGFR-2 signaling in endothelial cells; CLEC14A-KO mice show cerebral vascular leakage and exacerbated ischemic stroke injury that is suppressed by VEGFR-2 blockade, establishing CLEC14A as a negative regulator of VEGFR-2-driven BBB dysfunction.","method":"siRNA knockdown (in vitro FITC-dextran permeability, TEER assay), CLEC14A-KO mice, Evans blue/FITC-dextran leakage, MCAO stroke model, Western blotting, immunofluorescence","journal":"Journal of neuroinflammation","confidence":"High","confidence_rationale":"Tier 2 — KO mouse with defined molecular mechanism (VEGFR-2) and epistasis via blockade, multiple orthogonal methods","pmids":["32019570"],"is_preprint":false},{"year":2021,"finding":"CLEC14A directly binds HMGB1 in podocytes, inhibiting HMGB1 release and thereby suppressing HMGB1-mediated NF-κB and EGR1 signaling; CLEC14A deficiency exacerbates podocyte injury and proteinuria in adriamycin nephropathy mice.","method":"Co-immunoprecipitation (direct binding), CLEC14A overexpression in podocytes, CLEC14A-KO mice with adriamycin nephropathy model, Western blotting, NF-κB/EGR1 signaling assays","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2 — Co-IP for direct binding plus KO mouse phenotype with pathway analysis, single lab","pmids":["34107098"],"is_preprint":false},{"year":2024,"finding":"Clec14a on type-H endothelial cells orchestrates osteoblast maturation and bone formation via its interaction with Mmrn2; Clec14a-/- mice show premature condensation of type-H vasculature and expanded osteoblast distribution/activity; antibody-mediated blockade of the Clec14a-Mmrn2 interaction recapitulates the Clec14a-/- bone phenotype.","method":"Clec14a-/- mouse model, antibody-mediated blockade of Clec14a-Mmrn2 interaction, histological and immunofluorescence analysis of bone and vasculature","journal":"Communications biology","confidence":"Medium","confidence_rationale":"Tier 2 — KO mouse with defined cellular phenotype and antibody-based epistasis confirming Mmrn2 interaction mediates function","pmids":["39394430"],"is_preprint":false},{"year":2026,"finding":"FLI1 acts as a direct transcriptional activator of CLEC14A; CLEC14A in turn regulates VEGFC expression; knockdown of CLEC14A decreases VEGFC and impairs angiogenesis, while CLEC14A overexpression rescues DFMO-induced VEGFC downregulation, establishing a FLI1-CLEC14A-VEGFC regulatory axis in retinal endothelial angiogenesis.","method":"Dual-luciferase reporter assay (FLI1→CLEC14A), siRNA knockdown, CLEC14A overexpression, in vivo choroidal neovascularization mouse model","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 — luciferase reporter for direct transcriptional regulation, functional rescue with overexpression, single lab","pmids":["41548484"],"is_preprint":false}],"current_model":"CLEC14A is a single-pass transmembrane C-type lectin glycoprotein expressed selectively on vascular (and type-H bone) endothelial cells that promotes angiogenesis by mediating endothelial cell-cell adhesion through its CTLD, binding extracellular matrix protein MMRN2 (via a long-loop region in the CTLD) and heparan sulfate to regulate sprouting; its ectodomain is shed by the protease RHBDL2 to generate a soluble inhibitor of tip-cell sprouting; it forms a complex with VEGFR-3 to maintain VEGFR-2/VEGFR-3 signaling balance; it binds HSP70-1A to modulate ERK-driven tube formation; it binds HMGB1 to suppress NF-κB/EGR1 inflammation in podocytes; and its transcription is directly activated by the ETS factor FLI1, placing CLEC14A upstream of VEGFC in an angiogenic regulatory axis."},"narrative":{"teleology":[{"year":2010,"claim":"The first mechanistic question—how CLEC14A influences endothelial behavior—was answered by showing that its CTLD mediates cell-cell adhesion and that knockdown impairs migration, filopodia, and tube formation, establishing CLEC14A as a pro-angiogenic adhesion molecule.","evidence":"Deletion mutant analysis and siRNA knockdown with migration and tube-formation assays in endothelial cells","pmids":["21095181"],"confidence":"Medium","gaps":["Mechanism by which CTLD mediates homophilic adhesion not structurally resolved","Ligands of CTLD unknown at this stage","In vivo relevance not yet demonstrated"]},{"year":2011,"claim":"CLEC14A was validated as a tumor endothelial marker with in vivo relevance, as it promoted vascular development in zebrafish, extending its role beyond cultured cells to organismal angiogenesis.","evidence":"Overexpression, anti-CLEC14A antisera inhibition, zebrafish vascular development assay, immunohistochemistry of tumor vasculature","pmids":["21706054"],"confidence":"Medium","gaps":["Molecular partners mediating in vivo angiogenesis unidentified","Mechanism of filopodia induction not defined"]},{"year":2013,"claim":"Domain-specific antibodies confirmed the CTLD as the key functional domain for cell-cell contact and showed that antibody cross-linking downregulates CLEC14A surface expression, revealing a potential feedback mechanism.","evidence":"Phage-display-derived anti-CTLD antibodies blocking migration, tube formation, and CTLD-CTLD interactions","pmids":["23644659"],"confidence":"Medium","gaps":["Endocytic fate of cross-linked CLEC14A not characterized","Identity of CTLD binding partners still unknown"]},{"year":2015,"claim":"The question of what extracellular ligand CLEC14A engages was resolved by demonstrating direct binding to the ECM protein Multimerin-2, with antibody blockade of this interaction inhibiting sprouting angiogenesis and tumor growth in vivo.","evidence":"Reciprocal co-immunoprecipitation, pull-down, monoclonal antibody C4 blocking in aortic ring and tumor xenograft models","pmids":["25745997"],"confidence":"High","gaps":["Binding site on CLEC14A not yet mapped","Downstream signaling triggered by MMRN2 binding undefined"]},{"year":2016,"claim":"Two major advances resolved how CLEC14A is regulated post-translationally and how it interfaces with VEGFR signaling: RHBDL2-mediated ectodomain shedding generates a soluble inhibitor of tip-cell sprouting, and CLEC14A forms a complex with VEGFR-3 to maintain VEGFR-2/VEGFR-3 signaling balance, with its loss shifting signaling toward excess VEGFR-2 activity.","evidence":"Site-directed mutagenesis mapping the RHBDL2 cleavage site, siRNA specificity, in vivo sponge implant (shedding); co-immunoprecipitation, CLEC14A-KO mouse, VEGFR-2 blockade epistasis (VEGFR-3 complex)","pmids":["26939791","27991863"],"confidence":"High","gaps":["Signals controlling RHBDL2 activity toward CLEC14A unknown","Structural basis of CLEC14A–VEGFR-3 complex not determined","Whether shed ectodomain acts on VEGFR signaling not tested"]},{"year":2017,"claim":"The MMRN2-binding mechanism was refined: a long-loop region in the CTLD is required for MMRN2 binding; CLEC14A and CD93 compete for the same MMRN2 coiled-coil region whereas CD248 binds a distinct site, enabling simultaneous CLEC14A–MMRN2–CD248 complexes at endothelial-pericyte interfaces. Separately, HSP70-1A was identified as a CTLD ligand (residues 43–69) that drives ERK-dependent tube formation.","evidence":"Domain mutagenesis, competition assays, tissue co-localization (MMRN2); Co-IP, in vitro binding, competitive blocking, ERK phosphorylation assays (HSP70-1A)","pmids":["28671670","28878328"],"confidence":"High","gaps":["Functional consequence of CLEC14A–CD93 competition for MMRN2 in vivo not established","Whether HSP70-1A binding and MMRN2 binding are mutually exclusive unknown"]},{"year":2020,"claim":"CLEC14A's glycosaminoglycan engagement was defined—the CTLD binds heparin 1:1 with nanomolar affinity and interacts with endothelial heparan sulfate and chondroitin sulfate E—and its physiological importance was extended to brain vascular integrity, as CLEC14A-KO mice exhibit increased BBB permeability and worsened ischemic stroke through VEGFR-2 hyperactivation.","evidence":"Heparin-affinity chromatography, mutagenesis-based site mapping, affinity measurements (GAG binding); siRNA knockdown, CLEC14A-KO mice, MCAO stroke model, Evans blue leakage, VEGFR-2 blockade (BBB)","pmids":["31964714","32019570"],"confidence":"High","gaps":["Specific heparan sulfate epitope on endothelial surface not identified","Whether heparin binding and MMRN2 binding are coordinated not tested","Tight-junction regulation mechanism downstream of VEGFR-2 not fully dissected"]},{"year":2021,"claim":"CLEC14A's function was extended beyond endothelium to podocytes, where it directly binds HMGB1 and restrains HMGB1-mediated NF-κB/EGR1 inflammatory signaling; its deficiency worsens podocyte injury and proteinuria.","evidence":"Co-immunoprecipitation in podocytes, CLEC14A overexpression, CLEC14A-KO mice with adriamycin nephropathy","pmids":["34107098"],"confidence":"Medium","gaps":["Binding site on CLEC14A for HMGB1 not mapped","Whether HMGB1 binding involves the CTLD not tested","Independent replication in a second nephropathy model lacking"]},{"year":2024,"claim":"In bone, CLEC14A on type-H endothelial cells restrains premature vascular condensation and osteoblast expansion through its interaction with MMRN2, broadening the CLEC14A–MMRN2 axis beyond tumor angiogenesis to skeletal development.","evidence":"Clec14a-/- mouse skeletal phenotyping, antibody-mediated blockade of Clec14a–Mmrn2 interaction recapitulating KO phenotype","pmids":["39394430"],"confidence":"Medium","gaps":["Signaling pathway downstream of CLEC14A–MMRN2 in osteogenesis not identified","Contribution of CLEC14A–VEGFR-3 complex to bone phenotype not assessed"]},{"year":2026,"claim":"The transcriptional control of CLEC14A was resolved: the ETS factor FLI1 directly activates CLEC14A transcription, and CLEC14A in turn promotes VEGFC expression, establishing a FLI1–CLEC14A–VEGFC axis governing retinal angiogenesis.","evidence":"Dual-luciferase reporter assay for FLI1→CLEC14A, siRNA knockdown and overexpression rescue, in vivo choroidal neovascularization model","pmids":["41548484"],"confidence":"Medium","gaps":["Mechanism by which CLEC14A regulates VEGFC expression (transcriptional vs. post-transcriptional) not defined","Whether FLI1 regulation is conserved in non-retinal vascular beds untested"]},{"year":null,"claim":"Key open questions remain: the structural basis of the CLEC14A–VEGFR-3 complex, the mechanism by which CLEC14A controls VEGFC expression, whether CLEC14A's multiple ligand interactions (MMRN2, heparan sulfate, HSP70-1A, HMGB1) are spatially or temporally segregated, and how RHBDL2 shedding is physiologically regulated.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model of CLEC14A CTLD or its complexes available","Integration of shedding, VEGFR-3 complex formation, and MMRN2 binding in a unified signaling model lacking","Role of CLEC14A in human genetic disease not established"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098631","term_label":"cell adhesion mediator activity","supporting_discovery_ids":[0,2,8]},{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[10]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[5,11]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,1,2,4,8]},{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[4]},{"term_id":"GO:0031012","term_label":"extracellular matrix","supporting_discovery_ids":[3,6]}],"pathway":[{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[1,9,13]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[5,7,11]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[12]}],"complexes":["CLEC14A–VEGFR-3 complex"],"partners":["MMRN2","VEGFR3","RHBDL2","HSPA1A","HMGB1","CD93","CD248","FLI1"],"other_free_text":[]},"mechanistic_narrative":"CLEC14A is an endothelial-selective transmembrane C-type lectin that promotes angiogenesis and maintains vascular homeostasis by mediating cell-cell adhesion, sprouting, and signaling balance through its C-type lectin-like domain (CTLD). The CTLD drives homophilic endothelial cell-cell contact and directly binds the extracellular matrix protein Multimerin-2 (MMRN2) via a long-loop region, as well as heparan sulfate with nanomolar affinity, to regulate sprouting angiogenesis and tumor vascularization; its ectodomain is proteolytically shed by the rhomboid protease RHBDL2 to generate a soluble fragment that inhibits tip-cell sprouting [PMID:25745997, PMID:28671670, PMID:31964714, PMID:26939791]. CLEC14A forms a complex with VEGFR-3 and constrains VEGFR-2 signaling, such that its loss elevates VEGFR-2 activity, disrupts blood-brain barrier integrity, and worsens ischemic injury, while in bone it restrains type-H endothelial condensation and osteoblast maturation through MMRN2 binding [PMID:27991863, PMID:32019570, PMID:39394430]. FLI1 directly activates CLEC14A transcription, and CLEC14A in turn promotes VEGFC expression, positioning it within a FLI1–CLEC14A–VEGFC angiogenic axis; additionally, CLEC14A binds HMGB1 in podocytes to suppress NF-κB/EGR1-driven inflammation [PMID:41548484, PMID:34107098]."},"prefetch_data":{"uniprot":{"accession":"Q86T13","full_name":"C-type lectin domain family 14 member A","aliases":["Epidermal growth factor receptor 5","EGFR-5"],"length_aa":490,"mass_kda":51.6,"function":"","subcellular_location":"Membrane","url":"https://www.uniprot.org/uniprotkb/Q86T13/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/CLEC14A","classification":"Not Classified","n_dependent_lines":12,"n_total_lines":1208,"dependency_fraction":0.009933774834437087},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/CLEC14A","total_profiled":1310},"omim":[{"mim_id":"616845","title":"C-TYPE LECTIN DOMAIN FAMILY 14, MEMBER A; CLEC14A","url":"https://www.omim.org/entry/616845"},{"mim_id":"608925","title":"MULTIMERIN 2; MMRN2","url":"https://www.omim.org/entry/608925"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Endoplasmic reticulum","reliability":"Supported"},{"location":"Golgi apparatus","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in many","driving_tissues":[],"url":"https://www.proteinatlas.org/search/CLEC14A"},"hgnc":{"alias_symbol":[],"prev_symbol":["C14orf27"]},"alphafold":{"accession":"Q86T13","domains":[{"cath_id":"3.10.100.10","chopping":"29-175","consensus_level":"high","plddt":90.5244,"start":29,"end":175},{"cath_id":"-","chopping":"179-245","consensus_level":"medium","plddt":90.7763,"start":179,"end":245},{"cath_id":"-","chopping":"247-290","consensus_level":"medium","plddt":89.9605,"start":247,"end":290}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q86T13","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q86T13-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q86T13-F1-predicted_aligned_error_v6.png","plddt_mean":68.5},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CLEC14A","jax_strain_url":"https://www.jax.org/strain/search?query=CLEC14A"},"sequence":{"accession":"Q86T13","fasta_url":"https://rest.uniprot.org/uniprotkb/Q86T13.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q86T13/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q86T13"}},"corpus_meta":[{"pmid":"21706054","id":"PMC_21706054","title":"Identification and angiogenic role of the novel tumor endothelial marker CLEC14A.","date":"2011","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/21706054","citation_count":97,"is_preprint":false},{"pmid":"28671670","id":"PMC_28671670","title":"Multimerin-2 is a ligand for group 14 family C-type lectins CLEC14A, CD93 and CD248 spanning the endothelial pericyte interface.","date":"2017","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/28671670","citation_count":68,"is_preprint":false},{"pmid":"32019570","id":"PMC_32019570","title":"CLEC14A deficiency exacerbates neuronal loss by increasing blood-brain barrier permeability and inflammation.","date":"2020","source":"Journal of neuroinflammation","url":"https://pubmed.ncbi.nlm.nih.gov/32019570","citation_count":63,"is_preprint":false},{"pmid":"25745997","id":"PMC_25745997","title":"Blocking CLEC14A-MMRN2 binding inhibits sprouting angiogenesis and tumour growth.","date":"2015","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/25745997","citation_count":45,"is_preprint":false},{"pmid":"21095181","id":"PMC_21095181","title":"Clec14a is specifically expressed in endothelial cells and mediates cell to cell adhesion.","date":"2010","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/21095181","citation_count":45,"is_preprint":false},{"pmid":"30132150","id":"PMC_30132150","title":"Activin receptor-like kinase 1 is associated with immune cell infiltration and regulates CLEC14A transcription in cancer.","date":"2018","source":"Angiogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/30132150","citation_count":42,"is_preprint":false},{"pmid":"29316206","id":"PMC_29316206","title":"Inhibition of VEGF-dependent angiogenesis and tumor angiogenesis by an optimized antibody targeting CLEC14a.","date":"2018","source":"Molecular oncology","url":"https://pubmed.ncbi.nlm.nih.gov/29316206","citation_count":35,"is_preprint":false},{"pmid":"33004686","id":"PMC_33004686","title":"CAR T cells targeting tumor endothelial marker CLEC14A inhibit tumor growth.","date":"2020","source":"JCI insight","url":"https://pubmed.ncbi.nlm.nih.gov/33004686","citation_count":33,"is_preprint":false},{"pmid":"31852888","id":"PMC_31852888","title":"Human muscle-derived CLEC14A-positive cells regenerate muscle independent of PAX7.","date":"2019","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/31852888","citation_count":33,"is_preprint":false},{"pmid":"26939791","id":"PMC_26939791","title":"Sprouting angiogenesis is regulated by shedding of the C-type lectin family 14, member A (CLEC14A) ectodomain, catalyzed by rhomboid-like 2 protein (RHBDL2).","date":"2016","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/26939791","citation_count":32,"is_preprint":false},{"pmid":"31964714","id":"PMC_31964714","title":"Proteomics-based screening of the endothelial heparan sulfate interactome reveals that C-type lectin 14a (CLEC14A) is a heparin-binding protein.","date":"2020","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/31964714","citation_count":31,"is_preprint":false},{"pmid":"23644659","id":"PMC_23644659","title":"Human antibodies targeting the C-type lectin-like domain of the tumor endothelial cell marker clec14a regulate angiogenic properties in vitro.","date":"2013","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/23644659","citation_count":30,"is_preprint":false},{"pmid":"27991863","id":"PMC_27991863","title":"Carbohydrate-binding protein CLEC14A regulates VEGFR-2- and VEGFR-3-dependent signals during angiogenesis and lymphangiogenesis.","date":"2016","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/27991863","citation_count":29,"is_preprint":false},{"pmid":"28878328","id":"PMC_28878328","title":"CLEC14a-HSP70-1A interaction regulates HSP70-1A-induced angiogenesis.","date":"2017","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/28878328","citation_count":26,"is_preprint":false},{"pmid":"34107098","id":"PMC_34107098","title":"CLEC14A protects against podocyte injury in mice with adriamycin nephropathy.","date":"2021","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/34107098","citation_count":17,"is_preprint":false},{"pmid":"32696621","id":"PMC_32696621","title":"An evaluation of the tumour endothelial marker CLEC14A as a therapeutic target in solid tumours.","date":"2020","source":"The journal of pathology. Clinical research","url":"https://pubmed.ncbi.nlm.nih.gov/32696621","citation_count":15,"is_preprint":false},{"pmid":"30191970","id":"PMC_30191970","title":"Methylation of CLEC14A is associated with its expression and lung adenocarcinoma progression.","date":"2018","source":"Journal of cellular physiology","url":"https://pubmed.ncbi.nlm.nih.gov/30191970","citation_count":11,"is_preprint":false},{"pmid":"30953479","id":"PMC_30953479","title":"Clec14a genetically interacts with Etv2 and Vegf signaling during vasculogenesis and angiogenesis in zebrafish.","date":"2019","source":"BMC developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/30953479","citation_count":9,"is_preprint":false},{"pmid":"39454994","id":"PMC_39454994","title":"CLEC14A facilitates angiogenesis and alleviates inflammation in diabetic wound healing.","date":"2024","source":"Life sciences","url":"https://pubmed.ncbi.nlm.nih.gov/39454994","citation_count":5,"is_preprint":false},{"pmid":"39394430","id":"PMC_39394430","title":"Type-H endothelial cell protein Clec14a orchestrates osteoblast activity during trabecular bone formation and patterning.","date":"2024","source":"Communications biology","url":"https://pubmed.ncbi.nlm.nih.gov/39394430","citation_count":4,"is_preprint":false},{"pmid":"35576868","id":"PMC_35576868","title":"CLEC14A was up-regulated in hepatocellular carcinoma and may function as a potential diagnostic biomarker.","date":"2022","source":"Clinics (Sao Paulo, Brazil)","url":"https://pubmed.ncbi.nlm.nih.gov/35576868","citation_count":2,"is_preprint":false},{"pmid":"41548484","id":"PMC_41548484","title":"Alpha-difluoromethylornithine suppresses angiogenesis via the FLI1-CLEC14A-VEGFC pathway in retinal endothelial cells.","date":"2026","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/41548484","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.06.23.661087","title":"Transcriptomic Profiles from Normal and Tumor Tissue Samples Reveal Distinct Venule Populations and Novel Tumor Endothelial Cell Markers in Breast Cancer","date":"2025-06-27","source":"bioRxiv","url":"https://doi.org/10.1101/2025.06.23.661087","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":13161,"output_tokens":3793,"usd":0.048189},"stage2":{"model":"claude-opus-4-6","input_tokens":7207,"output_tokens":3327,"usd":0.178815},"total_usd":0.227004,"stage1_batch_id":"msgbatch_011kfMfE81o6CTcyhVUqumuW","stage2_batch_id":"msgbatch_01DTputS6WNkH745x1nVSoBo","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2010,\n      \"finding\": \"CLEC14A mediates endothelial cell-cell adhesion through its C-type lectin-like domain (CTLD), as demonstrated by deletion mutant analysis; knockdown in endothelial cells suppressed cell migratory activity, filopodial protrusion, and tube formation.\",\n      \"method\": \"Deletion mutant analysis, siRNA knockdown, cell migration and tube formation assays\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clean KD with defined cellular phenotype and domain mapping, single lab\",\n      \"pmids\": [\"21095181\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"CLEC14A is a tumor endothelial marker that induces filopodia, facilitates endothelial migration and tube formation, and promotes vascular development in zebrafish; anti-CLEC14A antisera inhibited cell migration and tube formation.\",\n      \"method\": \"Overexpression, antisera inhibition assays, zebrafish developmental assay, immunohistochemistry\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple functional assays in vitro and in vivo, single lab\",\n      \"pmids\": [\"21706054\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"The C-type lectin-like domain (CTLD) of CLEC14A is a key functional domain mediating cell-cell contact; antibodies targeting CTLD blocked endothelial cell migration, tube formation, and CTLD-CTLD interactions, and cross-linking downregulated CLEC14A surface expression.\",\n      \"method\": \"Phage display antibody selection, functional blocking assays, cell migration and tube formation assays\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — domain-specific antibody blocking with multiple functional readouts, single lab\",\n      \"pmids\": [\"23644659\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"CLEC14A binds directly to the extracellular matrix protein Multimerin-2 (MMRN2) via its extracellular region, as confirmed by pull-down and co-immunoprecipitation; this CLEC14A-MMRN2 interaction promotes sprouting angiogenesis and tumor growth, and blocking it with monoclonal antibody C4 inhibited endothelial sprouting and tumor growth in vivo.\",\n      \"method\": \"Pull-down, co-immunoprecipitation, monoclonal antibody blocking, aortic ring assay, in vivo tumor model\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — reciprocal Co-IP, antibody blocking, and in vivo functional validation\",\n      \"pmids\": [\"25745997\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"CLEC14A ectodomain is cleaved (shed) by rhomboid-like protease RHBDL2, but not RHBDL1 or RHBDL3; site-directed mutagenesis identified the precise cleavage site; the shed ectodomain inhibits sprouting angiogenesis and binds to sprouting endothelial tip cells.\",\n      \"method\": \"Site-directed mutagenesis, siRNA knockdown of CLEC14A and RHBDL2, in vitro sprouting assays, in vivo sponge implant model, recombinant protein addition\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — mutagenesis identifying cleavage site, siRNA specificity validation, in vitro and in vivo functional assays\",\n      \"pmids\": [\"26939791\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"CLEC14A forms a complex with VEGFR-3 in endothelial cells; CLEC14A knockout leads to reduced VEGFR-3 expression with concomitant increases in VEGFR-2 expression and downstream signaling, establishing CLEC14A as a regulator of VEGFR-2/VEGFR-3 balance in vascular homeostasis.\",\n      \"method\": \"Co-immunoprecipitation (complex formation), CLEC14A knockout mouse, Western blotting, in vivo vascular phenotype analysis, VEGFR-2 blockade epistasis\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP for complex, KO mouse with defined molecular and phenotypic readouts, epistasis with VEGFR-2 blockade\",\n      \"pmids\": [\"27991863\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"CLEC14A, CD93, and CD248 all directly bind to Multimerin-2 (MMRN2); binding is dependent on a long-loop region in the C-type lectin domain and is abrogated by mutation within this domain; CLEC14A and CD93 bind the same non-glycosylated coiled-coil region of MMRN2, whereas CD248 binds a distinct non-competing region; CLEC14A and CD248 can simultaneously bind MMRN2, occurring at the endothelial-pericyte interface in human pancreatic cancer.\",\n      \"method\": \"Direct binding assays, mutagenesis (long-loop region), recombinant protein competition assays, co-localization in human tissue\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct binding with mutagenesis, domain mapping, and functional blocking peptide validated in vitro and in vivo\",\n      \"pmids\": [\"28671670\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"HSP70-1A interacts with CLEC14A specifically at amino acids 43–69 of the CTLD; this interaction mediates HSP70-1A-induced ERK phosphorylation and endothelial tube formation; competitive blocking of this region inhibits HSP70-1A-induced angiogenesis.\",\n      \"method\": \"Proteomic isolation, co-immunoprecipitation, in vitro binding assays, competitive blocking experiments, ERK phosphorylation assay, tube formation assay\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP and in vitro binding with domain mapping and functional blocking, single lab\",\n      \"pmids\": [\"28878328\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"The CLEC14A C-type lectin-like domain (CTLD) mediates endothelial cell-cell contact in angiogenesis; an antibody targeting CTLD directly inhibits this cell-cell contact and simultaneously downregulates CLEC14A surface expression, suppressing VEGF-dependent and tumor angiogenesis in vitro and in vivo.\",\n      \"method\": \"CDR grafting antibody generation, cell-cell contact assays, in vitro tube formation, in vivo tumor xenograft models\",\n      \"journal\": \"Molecular oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — antibody-based mechanistic dissection with multiple in vitro and in vivo models, single lab\",\n      \"pmids\": [\"29316206\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"In zebrafish, clec14a genetically interacts with ETS transcription factor Etv2 and with Vegfa signaling in vasculogenesis and angiogenesis; partial knockdown of Etv2 or Vegfaa shows synergistic inhibition with clec14a mutation, placing Clec14a in the same pathway as Etv2 and Vegf signaling.\",\n      \"method\": \"TALEN genome editing (zebrafish clec14a mutant), morpholino knockdown, genetic epistasis, vascular phenotype analysis\",\n      \"journal\": \"BMC developmental biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — epistasis via double mutant/knockdown combinations in zebrafish, single lab\",\n      \"pmids\": [\"30953479\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"The C-type lectin domain of CLEC14A binds heparin in a 1:1 ratio with nanomolar affinity; molecular modeling and mutagenesis mapped the heparin-binding site within the CTLD; CLEC14A also physically interacts with endothelial heparan sulfate and chondroitin sulfate E but not neutral or sialylated oligosaccharides.\",\n      \"method\": \"Heparin-affinity chromatography (LPHAMS proteomics), molecular modeling, site-directed mutagenesis, binding affinity measurements\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro binding with affinity quantification, mutagenesis-based site mapping\",\n      \"pmids\": [\"31964714\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"CLEC14A deficiency increases BBB permeability by downregulating tight junctional proteins and activating VEGFR-2 signaling in endothelial cells; CLEC14A-KO mice show cerebral vascular leakage and exacerbated ischemic stroke injury that is suppressed by VEGFR-2 blockade, establishing CLEC14A as a negative regulator of VEGFR-2-driven BBB dysfunction.\",\n      \"method\": \"siRNA knockdown (in vitro FITC-dextran permeability, TEER assay), CLEC14A-KO mice, Evans blue/FITC-dextran leakage, MCAO stroke model, Western blotting, immunofluorescence\",\n      \"journal\": \"Journal of neuroinflammation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — KO mouse with defined molecular mechanism (VEGFR-2) and epistasis via blockade, multiple orthogonal methods\",\n      \"pmids\": [\"32019570\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"CLEC14A directly binds HMGB1 in podocytes, inhibiting HMGB1 release and thereby suppressing HMGB1-mediated NF-κB and EGR1 signaling; CLEC14A deficiency exacerbates podocyte injury and proteinuria in adriamycin nephropathy mice.\",\n      \"method\": \"Co-immunoprecipitation (direct binding), CLEC14A overexpression in podocytes, CLEC14A-KO mice with adriamycin nephropathy model, Western blotting, NF-κB/EGR1 signaling assays\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP for direct binding plus KO mouse phenotype with pathway analysis, single lab\",\n      \"pmids\": [\"34107098\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Clec14a on type-H endothelial cells orchestrates osteoblast maturation and bone formation via its interaction with Mmrn2; Clec14a-/- mice show premature condensation of type-H vasculature and expanded osteoblast distribution/activity; antibody-mediated blockade of the Clec14a-Mmrn2 interaction recapitulates the Clec14a-/- bone phenotype.\",\n      \"method\": \"Clec14a-/- mouse model, antibody-mediated blockade of Clec14a-Mmrn2 interaction, histological and immunofluorescence analysis of bone and vasculature\",\n      \"journal\": \"Communications biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — KO mouse with defined cellular phenotype and antibody-based epistasis confirming Mmrn2 interaction mediates function\",\n      \"pmids\": [\"39394430\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"FLI1 acts as a direct transcriptional activator of CLEC14A; CLEC14A in turn regulates VEGFC expression; knockdown of CLEC14A decreases VEGFC and impairs angiogenesis, while CLEC14A overexpression rescues DFMO-induced VEGFC downregulation, establishing a FLI1-CLEC14A-VEGFC regulatory axis in retinal endothelial angiogenesis.\",\n      \"method\": \"Dual-luciferase reporter assay (FLI1→CLEC14A), siRNA knockdown, CLEC14A overexpression, in vivo choroidal neovascularization mouse model\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — luciferase reporter for direct transcriptional regulation, functional rescue with overexpression, single lab\",\n      \"pmids\": [\"41548484\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CLEC14A is a single-pass transmembrane C-type lectin glycoprotein expressed selectively on vascular (and type-H bone) endothelial cells that promotes angiogenesis by mediating endothelial cell-cell adhesion through its CTLD, binding extracellular matrix protein MMRN2 (via a long-loop region in the CTLD) and heparan sulfate to regulate sprouting; its ectodomain is shed by the protease RHBDL2 to generate a soluble inhibitor of tip-cell sprouting; it forms a complex with VEGFR-3 to maintain VEGFR-2/VEGFR-3 signaling balance; it binds HSP70-1A to modulate ERK-driven tube formation; it binds HMGB1 to suppress NF-κB/EGR1 inflammation in podocytes; and its transcription is directly activated by the ETS factor FLI1, placing CLEC14A upstream of VEGFC in an angiogenic regulatory axis.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"CLEC14A is an endothelial-selective transmembrane C-type lectin that promotes angiogenesis and maintains vascular homeostasis by mediating cell-cell adhesion, sprouting, and signaling balance through its C-type lectin-like domain (CTLD). The CTLD drives homophilic endothelial cell-cell contact and directly binds the extracellular matrix protein Multimerin-2 (MMRN2) via a long-loop region, as well as heparan sulfate with nanomolar affinity, to regulate sprouting angiogenesis and tumor vascularization; its ectodomain is proteolytically shed by the rhomboid protease RHBDL2 to generate a soluble fragment that inhibits tip-cell sprouting [PMID:25745997, PMID:28671670, PMID:31964714, PMID:26939791]. CLEC14A forms a complex with VEGFR-3 and constrains VEGFR-2 signaling, such that its loss elevates VEGFR-2 activity, disrupts blood-brain barrier integrity, and worsens ischemic injury, while in bone it restrains type-H endothelial condensation and osteoblast maturation through MMRN2 binding [PMID:27991863, PMID:32019570, PMID:39394430]. FLI1 directly activates CLEC14A transcription, and CLEC14A in turn promotes VEGFC expression, positioning it within a FLI1–CLEC14A–VEGFC angiogenic axis; additionally, CLEC14A binds HMGB1 in podocytes to suppress NF-κB/EGR1-driven inflammation [PMID:41548484, PMID:34107098].\",\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"The first mechanistic question—how CLEC14A influences endothelial behavior—was answered by showing that its CTLD mediates cell-cell adhesion and that knockdown impairs migration, filopodia, and tube formation, establishing CLEC14A as a pro-angiogenic adhesion molecule.\",\n      \"evidence\": \"Deletion mutant analysis and siRNA knockdown with migration and tube-formation assays in endothelial cells\",\n      \"pmids\": [\"21095181\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which CTLD mediates homophilic adhesion not structurally resolved\", \"Ligands of CTLD unknown at this stage\", \"In vivo relevance not yet demonstrated\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"CLEC14A was validated as a tumor endothelial marker with in vivo relevance, as it promoted vascular development in zebrafish, extending its role beyond cultured cells to organismal angiogenesis.\",\n      \"evidence\": \"Overexpression, anti-CLEC14A antisera inhibition, zebrafish vascular development assay, immunohistochemistry of tumor vasculature\",\n      \"pmids\": [\"21706054\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular partners mediating in vivo angiogenesis unidentified\", \"Mechanism of filopodia induction not defined\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Domain-specific antibodies confirmed the CTLD as the key functional domain for cell-cell contact and showed that antibody cross-linking downregulates CLEC14A surface expression, revealing a potential feedback mechanism.\",\n      \"evidence\": \"Phage-display-derived anti-CTLD antibodies blocking migration, tube formation, and CTLD-CTLD interactions\",\n      \"pmids\": [\"23644659\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Endocytic fate of cross-linked CLEC14A not characterized\", \"Identity of CTLD binding partners still unknown\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"The question of what extracellular ligand CLEC14A engages was resolved by demonstrating direct binding to the ECM protein Multimerin-2, with antibody blockade of this interaction inhibiting sprouting angiogenesis and tumor growth in vivo.\",\n      \"evidence\": \"Reciprocal co-immunoprecipitation, pull-down, monoclonal antibody C4 blocking in aortic ring and tumor xenograft models\",\n      \"pmids\": [\"25745997\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Binding site on CLEC14A not yet mapped\", \"Downstream signaling triggered by MMRN2 binding undefined\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Two major advances resolved how CLEC14A is regulated post-translationally and how it interfaces with VEGFR signaling: RHBDL2-mediated ectodomain shedding generates a soluble inhibitor of tip-cell sprouting, and CLEC14A forms a complex with VEGFR-3 to maintain VEGFR-2/VEGFR-3 signaling balance, with its loss shifting signaling toward excess VEGFR-2 activity.\",\n      \"evidence\": \"Site-directed mutagenesis mapping the RHBDL2 cleavage site, siRNA specificity, in vivo sponge implant (shedding); co-immunoprecipitation, CLEC14A-KO mouse, VEGFR-2 blockade epistasis (VEGFR-3 complex)\",\n      \"pmids\": [\"26939791\", \"27991863\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Signals controlling RHBDL2 activity toward CLEC14A unknown\", \"Structural basis of CLEC14A–VEGFR-3 complex not determined\", \"Whether shed ectodomain acts on VEGFR signaling not tested\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"The MMRN2-binding mechanism was refined: a long-loop region in the CTLD is required for MMRN2 binding; CLEC14A and CD93 compete for the same MMRN2 coiled-coil region whereas CD248 binds a distinct site, enabling simultaneous CLEC14A–MMRN2–CD248 complexes at endothelial-pericyte interfaces. Separately, HSP70-1A was identified as a CTLD ligand (residues 43–69) that drives ERK-dependent tube formation.\",\n      \"evidence\": \"Domain mutagenesis, competition assays, tissue co-localization (MMRN2); Co-IP, in vitro binding, competitive blocking, ERK phosphorylation assays (HSP70-1A)\",\n      \"pmids\": [\"28671670\", \"28878328\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of CLEC14A–CD93 competition for MMRN2 in vivo not established\", \"Whether HSP70-1A binding and MMRN2 binding are mutually exclusive unknown\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"CLEC14A's glycosaminoglycan engagement was defined—the CTLD binds heparin 1:1 with nanomolar affinity and interacts with endothelial heparan sulfate and chondroitin sulfate E—and its physiological importance was extended to brain vascular integrity, as CLEC14A-KO mice exhibit increased BBB permeability and worsened ischemic stroke through VEGFR-2 hyperactivation.\",\n      \"evidence\": \"Heparin-affinity chromatography, mutagenesis-based site mapping, affinity measurements (GAG binding); siRNA knockdown, CLEC14A-KO mice, MCAO stroke model, Evans blue leakage, VEGFR-2 blockade (BBB)\",\n      \"pmids\": [\"31964714\", \"32019570\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific heparan sulfate epitope on endothelial surface not identified\", \"Whether heparin binding and MMRN2 binding are coordinated not tested\", \"Tight-junction regulation mechanism downstream of VEGFR-2 not fully dissected\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"CLEC14A's function was extended beyond endothelium to podocytes, where it directly binds HMGB1 and restrains HMGB1-mediated NF-κB/EGR1 inflammatory signaling; its deficiency worsens podocyte injury and proteinuria.\",\n      \"evidence\": \"Co-immunoprecipitation in podocytes, CLEC14A overexpression, CLEC14A-KO mice with adriamycin nephropathy\",\n      \"pmids\": [\"34107098\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Binding site on CLEC14A for HMGB1 not mapped\", \"Whether HMGB1 binding involves the CTLD not tested\", \"Independent replication in a second nephropathy model lacking\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"In bone, CLEC14A on type-H endothelial cells restrains premature vascular condensation and osteoblast expansion through its interaction with MMRN2, broadening the CLEC14A–MMRN2 axis beyond tumor angiogenesis to skeletal development.\",\n      \"evidence\": \"Clec14a-/- mouse skeletal phenotyping, antibody-mediated blockade of Clec14a–Mmrn2 interaction recapitulating KO phenotype\",\n      \"pmids\": [\"39394430\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Signaling pathway downstream of CLEC14A–MMRN2 in osteogenesis not identified\", \"Contribution of CLEC14A–VEGFR-3 complex to bone phenotype not assessed\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"The transcriptional control of CLEC14A was resolved: the ETS factor FLI1 directly activates CLEC14A transcription, and CLEC14A in turn promotes VEGFC expression, establishing a FLI1–CLEC14A–VEGFC axis governing retinal angiogenesis.\",\n      \"evidence\": \"Dual-luciferase reporter assay for FLI1→CLEC14A, siRNA knockdown and overexpression rescue, in vivo choroidal neovascularization model\",\n      \"pmids\": [\"41548484\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which CLEC14A regulates VEGFC expression (transcriptional vs. post-transcriptional) not defined\", \"Whether FLI1 regulation is conserved in non-retinal vascular beds untested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key open questions remain: the structural basis of the CLEC14A–VEGFR-3 complex, the mechanism by which CLEC14A controls VEGFC expression, whether CLEC14A's multiple ligand interactions (MMRN2, heparan sulfate, HSP70-1A, HMGB1) are spatially or temporally segregated, and how RHBDL2 shedding is physiologically regulated.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model of CLEC14A CTLD or its complexes available\", \"Integration of shedding, VEGFR-3 complex formation, and MMRN2 binding in a unified signaling model lacking\", \"Role of CLEC14A in human genetic disease not established\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098631\", \"supporting_discovery_ids\": [0, 2, 8]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [10]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [5, 11]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 1, 2, 4, 8]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [4]},\n      {\"term_id\": \"GO:0031012\", \"supporting_discovery_ids\": [3, 6]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [1, 9, 13]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [5, 7, 11]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [12]}\n    ],\n    \"complexes\": [\n      \"CLEC14A–VEGFR-3 complex\"\n    ],\n    \"partners\": [\n      \"MMRN2\",\n      \"VEGFR3\",\n      \"RHBDL2\",\n      \"HSPA1A\",\n      \"HMGB1\",\n      \"CD93\",\n      \"CD248\",\n      \"FLI1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}