Anti-Human CD9, Purified conjugated, clone HI9a

CD9 is a 24 kD type III transmembrane protein also known as tetraspanin, MRP-1 and DRAP-24. It is a member of the tetraspan family (spanning the membrane four times) found on platelets, B cell progenitors, activated lymphocytes, granulocytes, endothelial cells and epithelial cells. CD9 induces adhesion, platelet aggregation, and B cell development. CD9 has been shown to associate with CD63, CD81, CD82, and CD36 and to bind to beta1 integrins. Protein function: 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. In myoblasts, associates with CD81 and PTGFRN and inhibits myotube fusion during muscle regeneration. In macrophages, associates with CD81 and beta-1 and beta-2 integrins, and prevents macrophage fusion into multinucleated giant cells specialized in ingesting complement-opsonized large particles (PubMed:12796480). Also prevents the fusion between mononuclear cell progenitors into osteoclasts in charge of bone resorption. Acts as a receptor for PSG17. Involved in platelet activation and aggregation (PubMed:18541721). Regulates paranodal junction formation. Involved in cell adhesion, cell motility and tumor metastasis (PubMed:8478605, PubMed:7511626). [The UniProt Consortium]