6rlo

Structural highlights

Function

CD9_HUMAN 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). In myoblasts, associates with CD81 and PTGFRN and inhibits myotube fusion during muscle regeneration (By similarity). 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 (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).[UniProtKB:P40240]^{[1] [2] [3] [4] [5]}

References

1. ↑ Takeda Y, Tachibana I, Miyado K, Kobayashi M, Miyazaki T, Funakoshi T, Kimura H, Yamane H, Saito Y, Goto H, Yoneda T, Yoshida M, Kumagai T, Osaki T, Hayashi S, Kawase I, Mekada E. Tetraspanins CD9 and CD81 function to prevent the fusion of mononuclear phagocytes. J Cell Biol. 2003 Jun 9;161(5):945-56. doi: 10.1083/jcb.200212031. PMID:12796480 doi:http://dx.doi.org/10.1083/jcb.200212031
2. ↑ Higginbottom A, Takahashi Y, Bolling L, Coonrod SA, White JM, Partridge LJ, Monk PN. Structural requirements for the inhibitory action of the CD9 large extracellular domain in sperm/oocyte binding and fusion. Biochem Biophys Res Commun. 2003 Nov 7;311(1):208-14. doi:, 10.1016/j.bbrc.2003.09.196. PMID:14575715 doi:http://dx.doi.org/10.1016/j.bbrc.2003.09.196
3. ↑ Nakazawa Y, Sato S, Naito M, Kato Y, Mishima K, Arai H, Tsuruo T, Fujita N. Tetraspanin family member CD9 inhibits Aggrus/podoplanin-induced platelet aggregation and suppresses pulmonary metastasis. Blood. 2008 Sep 1;112(5):1730-9. doi: 10.1182/blood-2007-11-124693. Epub 2008 Jun, 9. PMID:18541721 doi:http://dx.doi.org/10.1182/blood-2007-11-124693
4. ↑ Masellis-Smith A, Shaw AR. CD9-regulated adhesion. Anti-CD9 monoclonal antibody induce pre-B cell adhesion to bone marrow fibroblasts through de novo recognition of fibronectin. J Immunol. 1994 Mar 15;152(6):2768-77. PMID:7511626
5. ↑ Ikeyama S, Koyama M, Yamaoko M, Sasada R, Miyake M. Suppression of cell motility and metastasis by transfection with human motility-related protein (MRP-1/CD9) DNA. J Exp Med. 1993 May 1;177(5):1231-7. doi: 10.1084/jem.177.5.1231. PMID:8478605 doi:http://dx.doi.org/10.1084/jem.177.5.1231