CD9 antigen - P21926 (CD9_HUMAN)


Protein Feature View of PDB entries mapped to a UniProtKB sequence  

Integral membrane protein associated with integrins, which regulates different processes, such as sperm-egg fusion, platelet activation and aggregation, and cell adhesion (PubMed:8478605, PubMed:14575715, PubMed:18541721). Present at the cell surface of oocytes and plays a key role in sperm-egg fusion, possibly by organizing multiprotein complexes and the morphology of the membrane required for the fusion (By similarity). Acts as a receptor for PSG17 (By similarity). Involved in platelet activation and aggregation (PubMed:18541721). Regulates paranodal junction formation (By similarity). Involved in cell adhesion, cell motility and tumor metastasis (PubMed:8478605, PubMed:7511626). UniProt
Pathway Maps
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Subunit Structure
Forms both disulfide-linked homodimers and higher homooligomers as well as heterooligomers with other members of the tetraspanin family (PubMed:14556650). Interacts (via the second extracellular domain) with integrin ITGAV:ITGB3 (PubMed:19640571, PubMed:27993971). Interacts with integrin ITGA6:ITGB1; interaction takes place in oocytes and is involved in sperm-egg fusion (By similarity). Interacts with CD63; identified in a complex with CD63 and ITGB3 (PubMed:19640571). Associates with CR2/CD21 and with PTGFRN/CD9P1 (PubMed:11278880). Interacts directly with IGSF8 (PubMed:11504738). Interacts with PDPN; this interaction is homophilic and attenuates platelet aggregation and pulmonary metastasis induced by PDPN (PubMed:18541721). UniProt
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