{"uniprot":"O94769","gene":"ECM2","name":"Extracellular matrix protein 2","organism":"Homo sapiens (Human)","status":"dark","length":699,"sequence":"MKIAVLFCFFLLIIFQTDFGKNEEIPRKQRRKIYHRRLRKSSTSHKHRSNRQLGIQQTTVFTPVARLPIVNFDYSMEEKFESFSSFPGVESSYNVLPGKKGHCLVKGITMYNKAVWSPEPCTTCLCSDGRVLCDETMCHPQRCPQTVIPEGECCPVCSATVSYSLLSGIALNDRNEFSGDSSEQREPTNLLHKQLPPPQVGMDRIVRKEALQSEEDEEVKEEDTEQKRETPESRNQGQLYSEGDSRGGDRKQRPGEERRLAHQQQRQGREEEEDEEEEGEEGEEDEEDEEDPVRGDMFRMPSRSPLPAPPRGTLRLPSGCSLSYRTISCINAMLTQIPPLTAPQITSLELTGNSIASIPDEAFNGLPNLERLDLSKNNITSSGIGPKAFKLLKKLMRLNMDGNNLIQIPSQLPSTLEELKVNENNLQAIDEESLSDLNQLVTLELEGNNLSEANVNPLAFKPLKSLAYLRLGKNKFRIIPQGLPGSIEELYLENNQIEEITEICFNHTRKINVIVLRYNKIEENRIAPLAWINQENLESIDLSYNKLYHVPSYLPKSLLHLVLLGNQIERIPGYVFGHMEPGLEYLYLSFNKLADDGMDRVSFYGAYHSLRELFLDHNDLKSIPPGIQEMKALHFLRLNNNKIRNILPEEICNAEEDDDSNLEHLHLENNYIKIREIPSYTFSCIRSYSSIVLKPQNIK","function_summary":"A secreted extracellular matrix-associated adhesion modulator that uses an N-terminal adhesive module and an extended leucine-rich repeat scaffold to bind integrins and assemble higher-order complexes. By anchoring within matrix networks and engaging cell-surface adhesion receptors, it promotes stable cell–matrix attachment and associated signaling, thereby shaping adhesion and migration behaviors in the extracellular space.","plain_language":"ECM2 has barely been studied. The model's best guess: A secreted extracellular matrix-associated adhesion modulator that uses an N-terminal adhesive module and an extended leucine-rich repeat scaffold to bind integrins and assemble higher-order complexes. By anchoring within matrix networks and engaging cell-surface adhesion receptors, it promotes stable cell–matrix attachment and associated signaling, thereby shaping adhesion and migration behaviors in the extracellular space.","uniprot_summary":"Binds integrins and may be involved in cell adhesion and migration.","go_terms":{"molecular_function":[{"id":"GO:0005178","label":"integrin binding"}],"biological_process":[{"id":"GO:0007160","label":"cell-matrix adhesion"}],"cellular_component":[{"id":"GO:0031012","label":"extracellular matrix"}]},"interpro":[{"id":"IPR032675","name":"Leucine-rich repeat domain superfamily","type":"homologous_superfamily","start":315,"end":408},{"id":"IPR032675","name":"Leucine-rich repeat domain superfamily","type":"homologous_superfamily","start":409,"end":479},{"id":"IPR032675","name":"Leucine-rich repeat domain superfamily","type":"homologous_superfamily","start":480,"end":550},{"id":"IPR032675","name":"Leucine-rich repeat domain superfamily","type":"homologous_superfamily","start":551,"end":699},{"id":"IPR001007","name":"VWFC domain","type":"domain","start":101,"end":158},{"id":"IPR043184","name":"Extracellular matrix protein 2","type":"family","start":1,"end":699},{"id":"IPR001611","name":"Leucine-rich repeat","type":"repeat","start":343,"end":405},{"id":"IPR003591","name":"Leucine-rich repeat, typical subtype","type":"repeat","start":343,"end":365},{"id":"IPR003591","name":"Leucine-rich repeat, typical subtype","type":"repeat","start":366,"end":391},{"id":"IPR003591","name":"Leucine-rich repeat, typical subtype","type":"repeat","start":392,"end":415},{"id":"IPR003591","name":"Leucine-rich repeat, typical subtype","type":"repeat","start":416,"end":436},{"id":"IPR003591","name":"Leucine-rich repeat, typical subtype","type":"repeat","start":437,"end":462},{"id":"IPR003591","name":"Leucine-rich repeat, typical subtype","type":"repeat","start":463,"end":486},{"id":"IPR001611","name":"Leucine-rich repeat","type":"repeat","start":486,"end":557},{"id":"IPR003591","name":"Leucine-rich repeat, typical subtype","type":"repeat","start":488,"end":507},{"id":"IPR003591","name":"Leucine-rich repeat, typical subtype","type":"repeat","start":535,"end":557},{"id":"IPR003591","name":"Leucine-rich repeat, typical subtype","type":"repeat","start":558,"end":578},{"id":"IPR003591","name":"Leucine-rich repeat, typical subtype","type":"repeat","start":607,"end":629},{"id":"IPR001611","name":"Leucine-rich repeat","type":"repeat","start":609,"end":630},{"id":"IPR025875","name":"Leucine rich repeat 4","type":"repeat","start":609,"end":646},{"id":"IPR003591","name":"Leucine-rich repeat, typical subtype","type":"repeat","start":630,"end":654},{"id":"IPR003591","name":"Leucine-rich repeat, typical subtype","type":"repeat","start":660,"end":684}],"reasoning":"I begin by dissecting the domain architecture. An N-terminal IPR001007 VWFC domain (von Willebrand factor type C; residues 101–158) precedes a long series of leucine-rich repeat (LRR) modules that dominate the remainder of the protein. The LRR region is supported by multiple concordant signatures: IPR032675 Leucine-rich repeat domain superfamily spans residues 315–408, 409–479, 480–550, and 551–699, collectively defining a continuous LRR-based scaffold. Within this scaffold, there is a dense array of LRR repeats annotated by IPR001611 (residues 343–405 and 486–557) and by IPR003591 typical LRR subtype repeats across residues 343–436 and 488–654, indicating a curved solenoid surface specialized for protein–protein recognition. The VWFC module is a hallmark of secreted extracellular proteins that mediate matrix interactions and growth factor or integrin-associated assemblies.\n\nThis ordered architecture—an N-terminal VWFC adhesive module followed by an extended LRR solenoid—causally establishes a high-affinity, multivalent binding platform. LRR arrays create concave binding grooves that capture extracellular ligands and receptors; in this context, the architecture is ideally suited to engage integrins. This directly supports the molecular function formalized as GO:0005178 integrin binding. The VWFC domain can nucleate extracellular complex formation and matrix tethering, while the LRR scaffold stabilizes and specifies integrin interactions.\n\nIntegrin binding positions the protein squarely within adhesion biology. By coupling integrin engagement to extracellular matrix anchorage, the protein promotes stable cell–matrix contacts and signaling. This mechanistic coupling drives the biological process represented by GO:0007160 cell-matrix adhesion. The VWFC-to-LRR pipeline thus translates adhesive recognition into durable adhesion and downstream signaling.\n\nThe presence of a VWFC domain and the extensive extracellular LRR array argue for secretion and matrix association. This architecture lacks transmembrane features and instead favors soluble extracellular deployment. Therefore, the cellular component is the extracellular matrix, aligning with GO:0031012 extracellular matrix. The experimentally observed secreted status is mechanistically explained by the VWFC-mediated secretion/matrix-binding system and the adhesive LRR scaffold.\n\nFrom this foundation, a mechanistic hypothesis emerges. The VWFC domain seeds assembly of extracellular complexes and anchors the protein within matrix networks. The LRR solenoid then presents an integrin-binding surface that modulates adhesion strength and signaling thresholds. Likely interaction partners include fibrillar matrix components and integrin heterodimers that govern adhesion and migration. I therefore hypothesize preferential association with extracellular matrix proteins such as fibronectin and collagens, and with integrins that govern cell–matrix adhesion dynamics. Together, these interactions would enable the protein to tune adhesion, migration, and matrix remodeling in the extracellular space.","category":"dark","control_evaluation":null,"validation_plan":null,"structure":{"source":"AlphaFold DB","pdb":"/structures/AF-O94769.pdb","alphafold":"https://alphafold.ebi.ac.uk/entry/O94769"},"links":{"uniprot":"https://www.uniprot.org/uniprotkb/O94769/entry","atlas":"/p/O94769"},"provenance":{"model":"BioReason-Pro (ESM3 esm3-sm-open-v1)","source_list":"Pharos Tdark","note":"AI prediction, not experimentally verified"}}