{"gene":"CLEC14A","run_date":"2026-06-09T22:57:18","timeline":{"discoveries":[{"year":2010,"finding":"CLEC14A is a plasma membrane protein specifically expressed in endothelial cells that mediates cell-cell adhesion through its C-type lectin-like domain (CTLD); deletion mutant analysis demonstrated the CTLD is required for this adhesion function, and knockdown suppressed cell migration, filopodial protrusion, and tube formation.","method":"Deletion mutant analysis, siRNA knockdown, cell adhesion and migration assays, tube formation assay","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — domain deletion mapping with functional readouts in multiple assays, single lab","pmids":["21095181"],"is_preprint":false},{"year":2011,"finding":"CLEC14A overexpression induces filopodia and facilitates endothelial cell migration and tube formation; anti-CLEC14A antisera inhibited cell migration and tube formation, and expression is induced by low shear stress in endothelial cultures.","method":"Overexpression studies, antibody inhibition assays, tube formation and migration assays, zebrafish in vivo vascular development assay","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — 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 mediates homotypic cell-cell contact between endothelial cells (CTLD-CTLD interaction); antibodies blocking CTLD inhibit endothelial migration and tube formation and downregulate CLEC14A surface expression.","method":"Phage display antibody selection, functional blocking assays, cell migration and tube formation assays, flow cytometry for surface expression","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — antibody blocking of specific domain with multiple functional readouts, single lab","pmids":["23644659"],"is_preprint":false},{"year":2015,"finding":"CLEC14A binds directly to MMRN2 (Multimerin-2) via its extracellular region; this interaction promotes sprouting angiogenesis and tumor vascularization, as blocking CLEC14A-MMRN2 binding with monoclonal antibody C4 phenocopies CLEC14A deficiency.","method":"Pull-down, co-immunoprecipitation, monoclonal antibody blocking, clec14a+/+ vs clec14a-/- mouse aortic ring and sponge assays, tumor growth models","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP/pulldown plus genetic KO plus in vivo antibody blocking, multiple orthogonal methods, replicated across assays","pmids":["25745997"],"is_preprint":false},{"year":2016,"finding":"CLEC14A ectodomain is specifically cleaved (shed) by rhomboid-like protease RHBDL2 but not by RHBDL1 or RHBDL3; site-directed mutagenesis identified the precise cleavage site; shed CLEC14A ectodomain inhibits sprouting angiogenesis and binds to tip cells, acting as a negative feedback regulator.","method":"Site-directed mutagenesis, siRNA knockdown of CLEC14A and RHBDL2, in vitro sprouting assays, rodent subcutaneous sponge implant in vivo assay, recombinant protein addition experiments","journal":"FASEB journal","confidence":"High","confidence_rationale":"Tier 1 / Moderate — mutagenesis identifying cleavage site plus siRNA validation plus in vitro and in vivo functional assays, single lab but multiple orthogonal methods","pmids":["26939791"],"is_preprint":false},{"year":2016,"finding":"CLEC14A forms a complex with VEGFR-3 in endothelial cells; CLEC14A KO results in markedly reduced VEGFR-3 expression and concomitant increase in VEGFR-2 expression and downstream signaling, demonstrating that CLEC14A regulates the balance between VEGFR-2 and VEGFR-3 signaling to maintain vascular homeostasis.","method":"Co-immunoprecipitation (CLEC14A-VEGFR-3 complex), CLEC14A knockout mice, Western blot for VEGFR-2/3 expression, in vivo angiogenesis and lymphangiogenesis phenotyping, VEGFR-2 blockade rescue experiment","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 2 / Strong — Co-IP plus genetic KO with defined molecular and phenotypic readouts plus pharmacological rescue, single lab but multiple orthogonal methods","pmids":["27991863"],"is_preprint":false},{"year":2017,"finding":"CLEC14A, CD93, and CD248 all directly bind MMRN2; binding requires a predicted long-loop region in the C-type lectin domain and is abrogated by mutation within this region. CLEC14A and CD93 bind to the same non-glycosylated coiled-coil region of MMRN2, while CD248 binds a distinct non-competing region. CLEC14A and CD248 can bind MMRN2 simultaneously at the endothelial-pericyte interface.","method":"Direct binding assays, mutagenesis of CLD long-loop region, competitive binding assays, recombinant MMRN2 peptide blocking of CLEC14A surface binding, HUVEC adhesion assays, pancreatic cancer tissue co-localization","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 1 / Strong — mutagenesis identifying binding determinants plus competitive binding plus functional blocking, multiple orthogonal methods","pmids":["28671670"],"is_preprint":false},{"year":2017,"finding":"CLEC14A CTLD directly binds HSP70-1A; the binding site on CLEC14A-CTLD spans amino acids 43–69; this interaction mediates HSP70-1A-induced ERK phosphorylation and endothelial tube formation, and a peptide of this CTLD region competitively inhibits HSP70-1A-induced angiogenesis.","method":"Proteomic isolation, co-immunoprecipitation, in vitro binding assays with truncation mapping, competitive blocking peptide experiments, ERK phosphorylation assay, tube formation assay","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus in vitro binding domain mapping plus functional inhibition assays, single lab","pmids":["28878328"],"is_preprint":false},{"year":2018,"finding":"The CTLD of CLEC14A mediates endothelial cell-cell contact required for VEGF-dependent angiogenesis; an anti-CLEC14A-CTLD humanized monoclonal antibody directly inhibits CTLD-mediated cell-cell contact, downregulates surface CLEC14A expression, and suppresses tumor angiogenesis in multiple xenograft models including bevacizumab-adapted tumors.","method":"Antibody engineering, in vitro cell-cell contact assays, VEGF-dependent angiogenesis assays, multiple mouse tumor xenograft models (SNU182, CFPAC-1, U87, HCT116, bevacizumab-adapted HCT116)","journal":"Molecular oncology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — domain-specific antibody blocking with multiple in vivo tumor models, single lab","pmids":["29316206"],"is_preprint":false},{"year":2019,"finding":"In zebrafish, clec14a genetically interacts with Etv2 (ETS transcription factor) and Vegfa signaling during vasculogenesis and angiogenesis; partial knockdown of Etv2 or Vegfaa in clec14a mutant background produces synergistic inhibition of vascular development, placing CLEC14A in the same pathway as Etv2 and VEGF signaling.","method":"TALEN-generated clec14a mutant zebrafish, morpholino knockdown, genetic epistasis (double mutant/knockdown), vascular marker expression analysis","journal":"BMC developmental biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis in zebrafish with multiple combinations, single lab","pmids":["30953479"],"is_preprint":false},{"year":2020,"finding":"CLEC14A loss increases VEGFR-2 signaling in endothelial cells, leading to increased BBB permeability (increased FITC-dextran leakage, decreased TEER, reduced tight junction proteins) and exacerbated neuroinflammation after ischemia-reperfusion injury in mice.","method":"CLEC14A knockdown in endothelial cells, CLEC14A-KO mice, FITC-dextran permeability assay, TEER assay, Evans blue dye injection, MCAO surgery model, Western blot, immunofluorescence","journal":"Journal of neuroinflammation","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KO mouse model with defined molecular readout (VEGFR-2 upregulation) and multiple phenotypic assays, single lab","pmids":["32019570"],"is_preprint":false},{"year":2020,"finding":"The C-type lectin domain of CLEC14A binds heparin with nanomolar (one-to-one stoichiometric) 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 with neutral or sialylated oligosaccharides.","method":"Proteomics-based LPHAMS workflow, heparin-affinity chromatography, LC-MS/MS, in vitro binding assays (quantified affinity), molecular modeling, site-directed mutagenesis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro binding reconstitution with affinity measurement plus mutagenesis mapping plus proteomics validation, single lab but multiple orthogonal methods","pmids":["31964714"],"is_preprint":false},{"year":2021,"finding":"CLEC14A is expressed in podocytes and directly binds HMGB1; this interaction inhibits HMGB1 release and suppresses HMGB1-mediated NF-κB and EGR1 signaling, thereby protecting against podocyte injury and inflammation.","method":"Co-immunoprecipitation (CLEC14A-HMGB1 binding), CLEC14A overexpression and knockdown in podocytes, CLEC14A-KO mice (adriamycin nephropathy model), Western blot for NF-κB/EGR1 signaling, HMGB1 release assay","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus KO mouse model plus signaling readouts, single lab","pmids":["34107098"],"is_preprint":false},{"year":2024,"finding":"Clec14a expressed in type-H endothelial cells regulates osteoblast maturation and mineralisation during postnatal bone development; Clec14a-/- mice show premature type-H vessel condensation, expanded osteoblast distribution, increased bone density, and enhanced osteoblast maturation; antibody-mediated blockade of Clec14a-Mmrn2 interaction recapitulates the KO phenotype, placing this effect downstream of Clec14a-Mmrn2 binding.","method":"Clec14a-/- mice (bone phenotyping), antibody blocking of Clec14a-Mmrn2 interaction, histology, immunofluorescence, bone density measurements","journal":"Communications biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO with defined phenotype plus antibody epistasis to specific interaction, single lab","pmids":["39394430"],"is_preprint":false},{"year":2024,"finding":"FLI1 is a direct transcriptional activator of CLEC14A; CLEC14A in turn positively regulates VEGFC expression in retinal endothelial cells, placing CLEC14A downstream of FLI1 and upstream of VEGFC in a regulatory angiogenic axis (FLI1-CLEC14A-VEGFC).","method":"Dual-luciferase reporter assay (FLI1 binding to CLEC14A promoter), siRNA knockdown of FLI1 and CLEC14A, CLEC14A overexpression rescue of VEGFC, transcriptome sequencing, in vivo choroidal neovascularization mouse model","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — luciferase reporter plus siRNA epistasis plus rescue experiment, single lab","pmids":["41548484"],"is_preprint":false},{"year":2026,"finding":"CLEC14A mediates firm adhesion of neutrophils to liver endothelium; siRNA knockdown of CLEC14A and CLEC14A-blocking antibodies reduced neutrophil firm adhesion in flow-based assays, and Clec14a-/- mice showed significantly reduced neutrophil recruitment across sinusoids in an ischemia-reperfusion liver injury model. This effect is independent of CLEC14A's interaction with MMRN2.","method":"siRNA knockdown, specific blocking antibodies, flow-based human liver endothelial neutrophil recruitment assay, in vivo Clec14a-/- mouse ischemia-reperfusion model","journal":"The Journal of pathology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA plus antibody blocking plus KO mouse in vivo, single lab, finding that MMRN2 interaction is not involved is a defined negative","pmids":["42223241"],"is_preprint":false},{"year":2026,"finding":"CLEC14A overexpression in trophoblast cells activates the cAMP/PKA signaling pathway (increased intracellular cAMP and PKA phosphorylation) while suppressing ERK phosphorylation, thereby impairing trophoblast migration, invasion, and tube formation; inhibition of adenylate cyclase (SQ22536) reverses these effects.","method":"Lentiviral CLEC14A overexpression in HTR-8/SVneo cells, RNA sequencing, ELISA (cAMP), Western blot (PKA/ERK phosphorylation), adenylate cyclase inhibitor rescue, migration/invasion/tube formation assays","journal":"Journal of molecular histology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — gain-of-function with pharmacological rescue and multiple signaling readouts, single lab","pmids":["42113307"],"is_preprint":false}],"current_model":"CLEC14A is an endothelial cell-surface transmembrane glycoprotein whose C-type lectin-like domain (CTLD) mediates homotypic endothelial cell-cell adhesion, binds extracellular matrix protein MMRN2 (to promote sprouting angiogenesis), binds heparan sulfate/heparin with nanomolar affinity, and interacts with HSP70-1A and HMGB1; it forms a complex with VEGFR-3 to maintain VEGFR-2/VEGFR-3 signaling balance, is transcriptionally activated by FLI1 and in turn regulates VEGFC expression, and its ectodomain is shed by the rhomboid protease RHBDL2 to generate a soluble inhibitor of angiogenesis, while CLEC14A on liver endothelium also mediates neutrophil firm adhesion independently of MMRN2."},"narrative":{"mechanistic_narrative":"CLEC14A is an endothelial cell-surface transmembrane glycoprotein that drives sprouting angiogenesis through its C-type lectin-like domain (CTLD), which mediates homotypic endothelial cell-cell contact required for migration, filopodial protrusion, and tube formation [PMID:21095181, PMID:23644659]. Its principal extracellular ligand is the matrix protein MMRN2 (Multimerin-2), which it binds directly via a long-loop region of the CTLD to promote sprouting angiogenesis and tumor vascularization; CLEC14A and CD93 engage the same non-glycosylated coiled-coil region of MMRN2, while CD248 occupies a distinct site, allowing CLEC14A and CD248 to bridge the endothelial-pericyte interface simultaneously [PMID:25745997, PMID:28671670]. CLEC14A forms a complex with VEGFR-3 and sets the balance between VEGFR-2 and VEGFR-3 signaling to maintain vascular homeostasis: its loss reduces VEGFR-3 and elevates VEGFR-2 signaling, increasing blood-brain barrier permeability and neuroinflammation after ischemia-reperfusion injury [PMID:27991863, PMID:32019570]. The receptor sits within a defined transcriptional axis, being directly activated by FLI1 and in turn driving VEGFC expression [PMID:41548484], and it genetically interacts with Etv2 and VEGF signaling during vascular development [PMID:30953479]. The CTLD additionally binds heparin and heparan/chondroitin sulfate E with nanomolar affinity [PMID:31964714] and engages HSP70-1A to support ERK-dependent tube formation [PMID:28878328]. CLEC14A activity is negatively regulated by RHBDL2-mediated ectodomain shedding, which releases a soluble inhibitor of angiogenesis that binds tip cells [PMID:26939791]. Beyond the vasculature, CLEC14A regulates type-H-vessel-dependent osteoblast maturation through its MMRN2 interaction [PMID:39394430], mediates MMRN2-independent firm adhesion of neutrophils to liver endothelium [PMID:42223241], binds HMGB1 in podocytes to suppress NF-κB/EGR1 inflammatory signaling [PMID:34107098], and modulates cAMP/PKA and ERK signaling in trophoblasts [PMID:42113307].","teleology":[{"year":2010,"claim":"Established CLEC14A as an endothelial-restricted plasma membrane protein whose CTLD mediates cell-cell adhesion and is required for angiogenic behaviors, defining its baseline cellular role.","evidence":"Deletion mutant mapping, siRNA knockdown, adhesion/migration/tube formation assays in endothelial cells","pmids":["21095181"],"confidence":"Medium","gaps":["No ligand identified for the CTLD at this stage","Adhesion mechanism (homotypic vs heterotypic) not yet resolved"]},{"year":2011,"claim":"Confirmed CLEC14A as a positive regulator of endothelial migration and tube formation in vitro and in vivo, and linked its expression to low shear stress.","evidence":"Overexpression, antibody inhibition, zebrafish vascular development assays","pmids":["21706054"],"confidence":"Medium","gaps":["Molecular mechanism of shear-stress induction unknown","No downstream signaling pathway defined"]},{"year":2013,"claim":"Resolved the adhesion mechanism as a CTLD-CTLD homotypic interaction and showed CTLD-blocking antibodies suppress angiogenesis, validating the domain as a therapeutic target.","evidence":"Phage-display antibody selection, functional blocking, flow cytometry for surface expression","pmids":["23644659"],"confidence":"Medium","gaps":["Whether homotypic contact is the sole adhesive mode unaddressed","No structural model of the CTLD-CTLD interface"]},{"year":2015,"claim":"Identified MMRN2 as the direct extracellular ligand whose engagement drives sprouting angiogenesis and tumor vascularization, defining the receptor-ligand axis.","evidence":"Reciprocal Co-IP/pull-down, monoclonal antibody C4 blocking, clec14a-/- mouse aortic ring/sponge and tumor models","pmids":["25745997"],"confidence":"High","gaps":["Binding determinants within the CTLD not yet mapped","Downstream signaling from CLEC14A-MMRN2 engagement undefined"]},{"year":2016,"claim":"Defined RHBDL2-mediated ectodomain shedding as a negative-feedback mechanism producing a soluble anti-angiogenic CLEC14A fragment that targets tip cells.","evidence":"Site-directed mutagenesis of cleavage site, siRNA of CLEC14A/RHBDL2, in vitro sprouting and in vivo sponge assays, recombinant fragment addition","pmids":["26939791"],"confidence":"High","gaps":["Regulation of RHBDL2 activity unknown","Receptor/target on tip cells for shed ectodomain not identified"]},{"year":2016,"claim":"Placed CLEC14A within VEGFR signaling by showing it complexes with VEGFR-3 and balances VEGFR-2/VEGFR-3 output to maintain vascular homeostasis.","evidence":"Co-IP, CLEC14A-KO mice, Western blot for VEGFR-2/3, in vivo angiogenesis/lymphangiogenesis phenotyping, VEGFR-2 blockade rescue","pmids":["27991863"],"confidence":"High","gaps":["Mechanism by which CLEC14A stabilizes VEGFR-3 unknown","Direct vs indirect nature of the complex not fully resolved"]},{"year":2017,"claim":"Mapped the MMRN2-binding determinant to a CTLD long-loop region and showed CLEC14A, CD93, and CD248 share/partition MMRN2 sites, enabling combinatorial endothelial-pericyte bridging.","evidence":"Direct binding and competitive assays, long-loop mutagenesis, MMRN2 peptide blocking, HUVEC adhesion, tissue co-localization","pmids":["28671670"],"confidence":"High","gaps":["Functional consequence of simultaneous CLEC14A/CD248 binding not dissected","Stoichiometry of the multi-receptor MMRN2 assembly unknown"]},{"year":2017,"claim":"Identified HSP70-1A as a CTLD ligand (residues 43-69) that drives ERK-dependent tube formation, broadening CLEC14A's ligand repertoire beyond MMRN2.","evidence":"Proteomic isolation, Co-IP, truncation binding mapping, competitive peptide, ERK phosphorylation and tube formation assays","pmids":["28878328"],"confidence":"Medium","gaps":["Physiological source of HSP70-1A ligand unclear","Link between HSP70-1A engagement and downstream ERK not mechanistically resolved"]},{"year":2019,"claim":"Positioned CLEC14A genetically within the Etv2/VEGFA developmental angiogenesis program via epistasis.","evidence":"TALEN clec14a mutant zebrafish, morpholino knockdown, double-mutant epistasis, vascular marker analysis","pmids":["30953479"],"confidence":"Medium","gaps":["Whether interaction is direct or pathway-level unresolved","No molecular link to Etv2 transcriptional targets"]},{"year":2020,"claim":"Extended the VEGFR-2 balance model to barrier function, showing CLEC14A loss elevates VEGFR-2 signaling, increases BBB permeability, and worsens neuroinflammation.","evidence":"Endothelial knockdown, CLEC14A-KO mice, permeability/TEER/Evans blue assays, MCAO model, Western blot","pmids":["32019570"],"confidence":"Medium","gaps":["Direct effect on tight junction proteins vs secondary to VEGFR-2 unresolved","Therapeutic window for CLEC14A modulation in stroke undefined"]},{"year":2020,"claim":"Demonstrated direct nanomolar heparin/heparan sulfate binding by the CTLD, identifying a glycosaminoglycan-recognition function and its structural determinants.","evidence":"Heparin-affinity chromatography, LC-MS/MS, quantified binding assays, molecular modeling, site-directed mutagenesis","pmids":["31964714"],"confidence":"High","gaps":["Physiological role of GAG binding in vivo unestablished","Relationship between heparin and MMRN2/HSP70 binding sites unresolved"]},{"year":2021,"claim":"Revealed a non-endothelial, anti-inflammatory role in podocytes via direct HMGB1 binding that suppresses HMGB1 release and NF-κB/EGR1 signaling.","evidence":"Co-IP, overexpression/knockdown in podocytes, CLEC14A-KO adriamycin nephropathy model, signaling Western blots, HMGB1 release assay","pmids":["34107098"],"confidence":"Medium","gaps":["Whether HMGB1 binding occurs intracellularly or at the surface unclear","Generalizability beyond podocytes untested"]},{"year":2024,"claim":"Showed CLEC14A on type-H endothelium restrains osteoblast maturation and bone mineralization downstream of its MMRN2 interaction, linking vascular CLEC14A to skeletal development.","evidence":"Clec14a-/- mice bone phenotyping, antibody blocking of Clec14a-Mmrn2, histology, bone density measurement","pmids":["39394430"],"confidence":"Medium","gaps":["Signal relaying vascular CLEC14A status to osteoblasts unknown","Cell-autonomous vs angiocrine contribution not separated"]},{"year":2024,"claim":"Defined a transcriptional axis in which FLI1 directly activates CLEC14A and CLEC14A drives VEGFC, embedding the receptor in a feed-forward angiogenic circuit.","evidence":"Dual-luciferase promoter reporter, siRNA epistasis, overexpression rescue, transcriptome sequencing, choroidal neovascularization model","pmids":["41548484"],"confidence":"Medium","gaps":["Mechanism by which CLEC14A regulates VEGFC transcription unknown","Whether axis operates outside retinal endothelium untested"]},{"year":2026,"claim":"Identified an MMRN2-independent function in immune cell trafficking, with CLEC14A mediating firm neutrophil adhesion to liver endothelium.","evidence":"siRNA, blocking antibodies, flow-based liver endothelial neutrophil recruitment assay, Clec14a-/- ischemia-reperfusion model","pmids":["42223241"],"confidence":"Medium","gaps":["Neutrophil counter-receptor for CLEC14A not identified","Whether this adhesion uses the CTLD or another domain unresolved"]},{"year":2026,"claim":"Showed CLEC14A modulates intracellular signaling balance (cAMP/PKA up, ERK down) to impair trophoblast migration, invasion, and tube formation.","evidence":"Lentiviral overexpression in HTR-8/SVneo cells, RNA-seq, cAMP ELISA, PKA/ERK Western blots, adenylate cyclase inhibitor rescue","pmids":["42113307"],"confidence":"Medium","gaps":["Receptor-proximal events linking CLEC14A to adenylate cyclase unknown","Physiological relevance in placentation in vivo untested"]},{"year":null,"claim":"How CLEC14A's distinct ligand-binding modes (MMRN2, heparin/HS, HSP70-1A, HMGB1) and the VEGFR-3 complex are integrated into context-specific signaling outputs across endothelial, immune, skeletal, renal, and trophoblast settings remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of the CTLD with any of its multiple ligands","Proximal intracellular signaling effectors of CLEC14A undefined","Counter-receptor mediating MMRN2-independent neutrophil adhesion unidentified"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098631","term_label":"cell adhesion mediator activity","supporting_discovery_ids":[0,2,3,15]},{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[11]},{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[5,7]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,2]},{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[3,4]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[5,10]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[3,9,13]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[12,15]}],"complexes":[],"partners":["MMRN2","VEGFR-3","HSP70-1A","HMGB1","CD93","CD248","RHBDL2","FLI1"],"other_free_text":[]}},"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":98,"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":66,"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":47,"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":46,"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 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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":"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":30,"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":"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":12,"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":6,"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":3,"is_preprint":false},{"pmid":"42113307","id":"PMC_42113307","title":"CLEC14A mediates trophoblast dysfunction in unexplained miscarriage by disrupting the cAMP/ERK signaling pathway.","date":"2026","source":"Journal of molecular histology","url":"https://pubmed.ncbi.nlm.nih.gov/42113307","citation_count":0,"is_preprint":false},{"pmid":"42057822","id":"PMC_42057822","title":"A novel methylation marker on the CLEC14A gene for cervical cancer screening.","date":"2026","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/42057822","citation_count":0,"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":"42223241","id":"PMC_42223241","title":"CLEC14A correlates with neutrophil infiltration in hepatocellular carcinoma and mediates neutrophil recruitment across liver endothelial cells.","date":"2026","source":"The Journal of pathology","url":"https://pubmed.ncbi.nlm.nih.gov/42223241","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":15659,"output_tokens":4549,"usd":0.057606,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":12490,"output_tokens":5144,"usd":0.095525,"stage2_stop_reason":"end_turn"},"total_usd":0.153131,"stage1_batch_id":"msgbatch_01ACAxJQabDsht39JXeWG22d","stage2_batch_id":"msgbatch_01QEU22A9U5sbPTgsMzTmvSf","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2010,\n      \"finding\": \"CLEC14A is a plasma membrane protein specifically expressed in endothelial cells that mediates cell-cell adhesion through its C-type lectin-like domain (CTLD); deletion mutant analysis demonstrated the CTLD is required for this adhesion function, and knockdown suppressed cell migration, filopodial protrusion, and tube formation.\",\n      \"method\": \"Deletion mutant analysis, siRNA knockdown, cell adhesion and migration assays, tube formation assay\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — domain deletion mapping with functional readouts in multiple assays, single lab\",\n      \"pmids\": [\"21095181\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"CLEC14A overexpression induces filopodia and facilitates endothelial cell migration and tube formation; anti-CLEC14A antisera inhibited cell migration and tube formation, and expression is induced by low shear stress in endothelial cultures.\",\n      \"method\": \"Overexpression studies, antibody inhibition assays, tube formation and migration assays, zebrafish in vivo vascular development assay\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — 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 mediates homotypic cell-cell contact between endothelial cells (CTLD-CTLD interaction); antibodies blocking CTLD inhibit endothelial migration and tube formation and downregulate CLEC14A surface expression.\",\n      \"method\": \"Phage display antibody selection, functional blocking assays, cell migration and tube formation assays, flow cytometry for surface expression\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — antibody blocking of specific domain with multiple functional readouts, single lab\",\n      \"pmids\": [\"23644659\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"CLEC14A binds directly to MMRN2 (Multimerin-2) via its extracellular region; this interaction promotes sprouting angiogenesis and tumor vascularization, as blocking CLEC14A-MMRN2 binding with monoclonal antibody C4 phenocopies CLEC14A deficiency.\",\n      \"method\": \"Pull-down, co-immunoprecipitation, monoclonal antibody blocking, clec14a+/+ vs clec14a-/- mouse aortic ring and sponge assays, tumor growth models\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP/pulldown plus genetic KO plus in vivo antibody blocking, multiple orthogonal methods, replicated across assays\",\n      \"pmids\": [\"25745997\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"CLEC14A ectodomain is specifically cleaved (shed) by rhomboid-like protease RHBDL2 but not by RHBDL1 or RHBDL3; site-directed mutagenesis identified the precise cleavage site; shed CLEC14A ectodomain inhibits sprouting angiogenesis and binds to tip cells, acting as a negative feedback regulator.\",\n      \"method\": \"Site-directed mutagenesis, siRNA knockdown of CLEC14A and RHBDL2, in vitro sprouting assays, rodent subcutaneous sponge implant in vivo assay, recombinant protein addition experiments\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — mutagenesis identifying cleavage site plus siRNA validation plus in vitro and in vivo functional assays, single lab but multiple orthogonal methods\",\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 KO results in markedly reduced VEGFR-3 expression and concomitant increase in VEGFR-2 expression and downstream signaling, demonstrating that CLEC14A regulates the balance between VEGFR-2 and VEGFR-3 signaling to maintain vascular homeostasis.\",\n      \"method\": \"Co-immunoprecipitation (CLEC14A-VEGFR-3 complex), CLEC14A knockout mice, Western blot for VEGFR-2/3 expression, in vivo angiogenesis and lymphangiogenesis phenotyping, VEGFR-2 blockade rescue experiment\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — Co-IP plus genetic KO with defined molecular and phenotypic readouts plus pharmacological rescue, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"27991863\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"CLEC14A, CD93, and CD248 all directly bind MMRN2; binding requires a predicted long-loop region in the C-type lectin domain and is abrogated by mutation within this region. CLEC14A and CD93 bind to the same non-glycosylated coiled-coil region of MMRN2, while CD248 binds a distinct non-competing region. CLEC14A and CD248 can bind MMRN2 simultaneously at the endothelial-pericyte interface.\",\n      \"method\": \"Direct binding assays, mutagenesis of CLD long-loop region, competitive binding assays, recombinant MMRN2 peptide blocking of CLEC14A surface binding, HUVEC adhesion assays, pancreatic cancer tissue co-localization\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — mutagenesis identifying binding determinants plus competitive binding plus functional blocking, multiple orthogonal methods\",\n      \"pmids\": [\"28671670\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"CLEC14A CTLD directly binds HSP70-1A; the binding site on CLEC14A-CTLD spans amino acids 43–69; this interaction mediates HSP70-1A-induced ERK phosphorylation and endothelial tube formation, and a peptide of this CTLD region competitively inhibits HSP70-1A-induced angiogenesis.\",\n      \"method\": \"Proteomic isolation, co-immunoprecipitation, in vitro binding assays with truncation mapping, competitive blocking peptide experiments, ERK phosphorylation assay, tube formation assay\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus in vitro binding domain mapping plus functional inhibition assays, single lab\",\n      \"pmids\": [\"28878328\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"The CTLD of CLEC14A mediates endothelial cell-cell contact required for VEGF-dependent angiogenesis; an anti-CLEC14A-CTLD humanized monoclonal antibody directly inhibits CTLD-mediated cell-cell contact, downregulates surface CLEC14A expression, and suppresses tumor angiogenesis in multiple xenograft models including bevacizumab-adapted tumors.\",\n      \"method\": \"Antibody engineering, in vitro cell-cell contact assays, VEGF-dependent angiogenesis assays, multiple mouse tumor xenograft models (SNU182, CFPAC-1, U87, HCT116, bevacizumab-adapted HCT116)\",\n      \"journal\": \"Molecular oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — domain-specific antibody blocking with multiple in vivo tumor models, single lab\",\n      \"pmids\": [\"29316206\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"In zebrafish, clec14a genetically interacts with Etv2 (ETS transcription factor) and Vegfa signaling during vasculogenesis and angiogenesis; partial knockdown of Etv2 or Vegfaa in clec14a mutant background produces synergistic inhibition of vascular development, placing CLEC14A in the same pathway as Etv2 and VEGF signaling.\",\n      \"method\": \"TALEN-generated clec14a mutant zebrafish, morpholino knockdown, genetic epistasis (double mutant/knockdown), vascular marker expression analysis\",\n      \"journal\": \"BMC developmental biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis in zebrafish with multiple combinations, single lab\",\n      \"pmids\": [\"30953479\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"CLEC14A loss increases VEGFR-2 signaling in endothelial cells, leading to increased BBB permeability (increased FITC-dextran leakage, decreased TEER, reduced tight junction proteins) and exacerbated neuroinflammation after ischemia-reperfusion injury in mice.\",\n      \"method\": \"CLEC14A knockdown in endothelial cells, CLEC14A-KO mice, FITC-dextran permeability assay, TEER assay, Evans blue dye injection, MCAO surgery model, Western blot, immunofluorescence\",\n      \"journal\": \"Journal of neuroinflammation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO mouse model with defined molecular readout (VEGFR-2 upregulation) and multiple phenotypic assays, single lab\",\n      \"pmids\": [\"32019570\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"The C-type lectin domain of CLEC14A binds heparin with nanomolar (one-to-one stoichiometric) 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 with neutral or sialylated oligosaccharides.\",\n      \"method\": \"Proteomics-based LPHAMS workflow, heparin-affinity chromatography, LC-MS/MS, in vitro binding assays (quantified affinity), molecular modeling, site-directed mutagenesis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro binding reconstitution with affinity measurement plus mutagenesis mapping plus proteomics validation, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"31964714\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"CLEC14A is expressed in podocytes and directly binds HMGB1; this interaction inhibits HMGB1 release and suppresses HMGB1-mediated NF-κB and EGR1 signaling, thereby protecting against podocyte injury and inflammation.\",\n      \"method\": \"Co-immunoprecipitation (CLEC14A-HMGB1 binding), CLEC14A overexpression and knockdown in podocytes, CLEC14A-KO mice (adriamycin nephropathy model), Western blot for NF-κB/EGR1 signaling, HMGB1 release assay\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus KO mouse model plus signaling readouts, single lab\",\n      \"pmids\": [\"34107098\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Clec14a expressed in type-H endothelial cells regulates osteoblast maturation and mineralisation during postnatal bone development; Clec14a-/- mice show premature type-H vessel condensation, expanded osteoblast distribution, increased bone density, and enhanced osteoblast maturation; antibody-mediated blockade of Clec14a-Mmrn2 interaction recapitulates the KO phenotype, placing this effect downstream of Clec14a-Mmrn2 binding.\",\n      \"method\": \"Clec14a-/- mice (bone phenotyping), antibody blocking of Clec14a-Mmrn2 interaction, histology, immunofluorescence, bone density measurements\",\n      \"journal\": \"Communications biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO with defined phenotype plus antibody epistasis to specific interaction, single lab\",\n      \"pmids\": [\"39394430\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"FLI1 is a direct transcriptional activator of CLEC14A; CLEC14A in turn positively regulates VEGFC expression in retinal endothelial cells, placing CLEC14A downstream of FLI1 and upstream of VEGFC in a regulatory angiogenic axis (FLI1-CLEC14A-VEGFC).\",\n      \"method\": \"Dual-luciferase reporter assay (FLI1 binding to CLEC14A promoter), siRNA knockdown of FLI1 and CLEC14A, CLEC14A overexpression rescue of VEGFC, transcriptome sequencing, in vivo choroidal neovascularization mouse model\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — luciferase reporter plus siRNA epistasis plus rescue experiment, single lab\",\n      \"pmids\": [\"41548484\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"CLEC14A mediates firm adhesion of neutrophils to liver endothelium; siRNA knockdown of CLEC14A and CLEC14A-blocking antibodies reduced neutrophil firm adhesion in flow-based assays, and Clec14a-/- mice showed significantly reduced neutrophil recruitment across sinusoids in an ischemia-reperfusion liver injury model. This effect is independent of CLEC14A's interaction with MMRN2.\",\n      \"method\": \"siRNA knockdown, specific blocking antibodies, flow-based human liver endothelial neutrophil recruitment assay, in vivo Clec14a-/- mouse ischemia-reperfusion model\",\n      \"journal\": \"The Journal of pathology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA plus antibody blocking plus KO mouse in vivo, single lab, finding that MMRN2 interaction is not involved is a defined negative\",\n      \"pmids\": [\"42223241\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"CLEC14A overexpression in trophoblast cells activates the cAMP/PKA signaling pathway (increased intracellular cAMP and PKA phosphorylation) while suppressing ERK phosphorylation, thereby impairing trophoblast migration, invasion, and tube formation; inhibition of adenylate cyclase (SQ22536) reverses these effects.\",\n      \"method\": \"Lentiviral CLEC14A overexpression in HTR-8/SVneo cells, RNA sequencing, ELISA (cAMP), Western blot (PKA/ERK phosphorylation), adenylate cyclase inhibitor rescue, migration/invasion/tube formation assays\",\n      \"journal\": \"Journal of molecular histology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — gain-of-function with pharmacological rescue and multiple signaling readouts, single lab\",\n      \"pmids\": [\"42113307\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CLEC14A is an endothelial cell-surface transmembrane glycoprotein whose C-type lectin-like domain (CTLD) mediates homotypic endothelial cell-cell adhesion, binds extracellular matrix protein MMRN2 (to promote sprouting angiogenesis), binds heparan sulfate/heparin with nanomolar affinity, and interacts with HSP70-1A and HMGB1; it forms a complex with VEGFR-3 to maintain VEGFR-2/VEGFR-3 signaling balance, is transcriptionally activated by FLI1 and in turn regulates VEGFC expression, and its ectodomain is shed by the rhomboid protease RHBDL2 to generate a soluble inhibitor of angiogenesis, while CLEC14A on liver endothelium also mediates neutrophil firm adhesion independently of MMRN2.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"CLEC14A is an endothelial cell-surface transmembrane glycoprotein that drives sprouting angiogenesis through its C-type lectin-like domain (CTLD), which mediates homotypic endothelial cell-cell contact required for migration, filopodial protrusion, and tube formation [#0, #2]. Its principal extracellular ligand is the matrix protein MMRN2 (Multimerin-2), which it binds directly via a long-loop region of the CTLD to promote sprouting angiogenesis and tumor vascularization; CLEC14A and CD93 engage the same non-glycosylated coiled-coil region of MMRN2, while CD248 occupies a distinct site, allowing CLEC14A and CD248 to bridge the endothelial-pericyte interface simultaneously [#3, #6]. CLEC14A forms a complex with VEGFR-3 and sets the balance between VEGFR-2 and VEGFR-3 signaling to maintain vascular homeostasis: its loss reduces VEGFR-3 and elevates VEGFR-2 signaling, increasing blood-brain barrier permeability and neuroinflammation after ischemia-reperfusion injury [#5, #10]. The receptor sits within a defined transcriptional axis, being directly activated by FLI1 and in turn driving VEGFC expression [#14], and it genetically interacts with Etv2 and VEGF signaling during vascular development [#9]. The CTLD additionally binds heparin and heparan/chondroitin sulfate E with nanomolar affinity [#11] and engages HSP70-1A to support ERK-dependent tube formation [#7]. CLEC14A activity is negatively regulated by RHBDL2-mediated ectodomain shedding, which releases a soluble inhibitor of angiogenesis that binds tip cells [#4]. Beyond the vasculature, CLEC14A regulates type-H-vessel-dependent osteoblast maturation through its MMRN2 interaction [#13], mediates MMRN2-independent firm adhesion of neutrophils to liver endothelium [#15], binds HMGB1 in podocytes to suppress NF-\\u03baB/EGR1 inflammatory signaling [#12], and modulates cAMP/PKA and ERK signaling in trophoblasts [#16].\",\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"Established CLEC14A as an endothelial-restricted plasma membrane protein whose CTLD mediates cell-cell adhesion and is required for angiogenic behaviors, defining its baseline cellular role.\",\n      \"evidence\": \"Deletion mutant mapping, siRNA knockdown, adhesion/migration/tube formation assays in endothelial cells\",\n      \"pmids\": [\"21095181\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No ligand identified for the CTLD at this stage\", \"Adhesion mechanism (homotypic vs heterotypic) not yet resolved\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Confirmed CLEC14A as a positive regulator of endothelial migration and tube formation in vitro and in vivo, and linked its expression to low shear stress.\",\n      \"evidence\": \"Overexpression, antibody inhibition, zebrafish vascular development assays\",\n      \"pmids\": [\"21706054\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular mechanism of shear-stress induction unknown\", \"No downstream signaling pathway defined\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Resolved the adhesion mechanism as a CTLD-CTLD homotypic interaction and showed CTLD-blocking antibodies suppress angiogenesis, validating the domain as a therapeutic target.\",\n      \"evidence\": \"Phage-display antibody selection, functional blocking, flow cytometry for surface expression\",\n      \"pmids\": [\"23644659\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether homotypic contact is the sole adhesive mode unaddressed\", \"No structural model of the CTLD-CTLD interface\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Identified MMRN2 as the direct extracellular ligand whose engagement drives sprouting angiogenesis and tumor vascularization, defining the receptor-ligand axis.\",\n      \"evidence\": \"Reciprocal Co-IP/pull-down, monoclonal antibody C4 blocking, clec14a-/- mouse aortic ring/sponge and tumor models\",\n      \"pmids\": [\"25745997\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Binding determinants within the CTLD not yet mapped\", \"Downstream signaling from CLEC14A-MMRN2 engagement undefined\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Defined RHBDL2-mediated ectodomain shedding as a negative-feedback mechanism producing a soluble anti-angiogenic CLEC14A fragment that targets tip cells.\",\n      \"evidence\": \"Site-directed mutagenesis of cleavage site, siRNA of CLEC14A/RHBDL2, in vitro sprouting and in vivo sponge assays, recombinant fragment addition\",\n      \"pmids\": [\"26939791\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Regulation of RHBDL2 activity unknown\", \"Receptor/target on tip cells for shed ectodomain not identified\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Placed CLEC14A within VEGFR signaling by showing it complexes with VEGFR-3 and balances VEGFR-2/VEGFR-3 output to maintain vascular homeostasis.\",\n      \"evidence\": \"Co-IP, CLEC14A-KO mice, Western blot for VEGFR-2/3, in vivo angiogenesis/lymphangiogenesis phenotyping, VEGFR-2 blockade rescue\",\n      \"pmids\": [\"27991863\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which CLEC14A stabilizes VEGFR-3 unknown\", \"Direct vs indirect nature of the complex not fully resolved\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Mapped the MMRN2-binding determinant to a CTLD long-loop region and showed CLEC14A, CD93, and CD248 share/partition MMRN2 sites, enabling combinatorial endothelial-pericyte bridging.\",\n      \"evidence\": \"Direct binding and competitive assays, long-loop mutagenesis, MMRN2 peptide blocking, HUVEC adhesion, tissue co-localization\",\n      \"pmids\": [\"28671670\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of simultaneous CLEC14A/CD248 binding not dissected\", \"Stoichiometry of the multi-receptor MMRN2 assembly unknown\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Identified HSP70-1A as a CTLD ligand (residues 43-69) that drives ERK-dependent tube formation, broadening CLEC14A's ligand repertoire beyond MMRN2.\",\n      \"evidence\": \"Proteomic isolation, Co-IP, truncation binding mapping, competitive peptide, ERK phosphorylation and tube formation assays\",\n      \"pmids\": [\"28878328\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Physiological source of HSP70-1A ligand unclear\", \"Link between HSP70-1A engagement and downstream ERK not mechanistically resolved\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Positioned CLEC14A genetically within the Etv2/VEGFA developmental angiogenesis program via epistasis.\",\n      \"evidence\": \"TALEN clec14a mutant zebrafish, morpholino knockdown, double-mutant epistasis, vascular marker analysis\",\n      \"pmids\": [\"30953479\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether interaction is direct or pathway-level unresolved\", \"No molecular link to Etv2 transcriptional targets\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Extended the VEGFR-2 balance model to barrier function, showing CLEC14A loss elevates VEGFR-2 signaling, increases BBB permeability, and worsens neuroinflammation.\",\n      \"evidence\": \"Endothelial knockdown, CLEC14A-KO mice, permeability/TEER/Evans blue assays, MCAO model, Western blot\",\n      \"pmids\": [\"32019570\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct effect on tight junction proteins vs secondary to VEGFR-2 unresolved\", \"Therapeutic window for CLEC14A modulation in stroke undefined\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Demonstrated direct nanomolar heparin/heparan sulfate binding by the CTLD, identifying a glycosaminoglycan-recognition function and its structural determinants.\",\n      \"evidence\": \"Heparin-affinity chromatography, LC-MS/MS, quantified binding assays, molecular modeling, site-directed mutagenesis\",\n      \"pmids\": [\"31964714\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological role of GAG binding in vivo unestablished\", \"Relationship between heparin and MMRN2/HSP70 binding sites unresolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Revealed a non-endothelial, anti-inflammatory role in podocytes via direct HMGB1 binding that suppresses HMGB1 release and NF-\\u03baB/EGR1 signaling.\",\n      \"evidence\": \"Co-IP, overexpression/knockdown in podocytes, CLEC14A-KO adriamycin nephropathy model, signaling Western blots, HMGB1 release assay\",\n      \"pmids\": [\"34107098\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether HMGB1 binding occurs intracellularly or at the surface unclear\", \"Generalizability beyond podocytes untested\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Showed CLEC14A on type-H endothelium restrains osteoblast maturation and bone mineralization downstream of its MMRN2 interaction, linking vascular CLEC14A to skeletal development.\",\n      \"evidence\": \"Clec14a-/- mice bone phenotyping, antibody blocking of Clec14a-Mmrn2, histology, bone density measurement\",\n      \"pmids\": [\"39394430\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Signal relaying vascular CLEC14A status to osteoblasts unknown\", \"Cell-autonomous vs angiocrine contribution not separated\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Defined a transcriptional axis in which FLI1 directly activates CLEC14A and CLEC14A drives VEGFC, embedding the receptor in a feed-forward angiogenic circuit.\",\n      \"evidence\": \"Dual-luciferase promoter reporter, siRNA epistasis, overexpression rescue, transcriptome sequencing, choroidal neovascularization model\",\n      \"pmids\": [\"41548484\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which CLEC14A regulates VEGFC transcription unknown\", \"Whether axis operates outside retinal endothelium untested\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Identified an MMRN2-independent function in immune cell trafficking, with CLEC14A mediating firm neutrophil adhesion to liver endothelium.\",\n      \"evidence\": \"siRNA, blocking antibodies, flow-based liver endothelial neutrophil recruitment assay, Clec14a-/- ischemia-reperfusion model\",\n      \"pmids\": [\"42223241\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Neutrophil counter-receptor for CLEC14A not identified\", \"Whether this adhesion uses the CTLD or another domain unresolved\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Showed CLEC14A modulates intracellular signaling balance (cAMP/PKA up, ERK down) to impair trophoblast migration, invasion, and tube formation.\",\n      \"evidence\": \"Lentiviral overexpression in HTR-8/SVneo cells, RNA-seq, cAMP ELISA, PKA/ERK Western blots, adenylate cyclase inhibitor rescue\",\n      \"pmids\": [\"42113307\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Receptor-proximal events linking CLEC14A to adenylate cyclase unknown\", \"Physiological relevance in placentation in vivo untested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How CLEC14A's distinct ligand-binding modes (MMRN2, heparin/HS, HSP70-1A, HMGB1) and the VEGFR-3 complex are integrated into context-specific signaling outputs across endothelial, immune, skeletal, renal, and trophoblast settings remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of the CTLD with any of its multiple ligands\", \"Proximal intracellular signaling effectors of CLEC14A undefined\", \"Counter-receptor mediating MMRN2-independent neutrophil adhesion unidentified\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098631\", \"supporting_discovery_ids\": [0, 2, 3, 15]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [11]},\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [5, 7]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [3, 4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [5, 10]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [3, 9, 13]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [12, 15]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"MMRN2\", \"VEGFR-3\", \"HSP70-1A\", \"HMGB1\", \"CD93\", \"CD248\", \"RHBDL2\", \"FLI1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"faith_supported":7,"faith_total":7,"faith_pct":100.0}}