| Post Translational Modifications | Palmitoylated at a low, basal level in unstimulated platelets. The level of palmitoylation increases when platelets are activated by thrombin (in vitro). The protein exists in three forms with molecular masses between 22 and 27 kDa, and is known to carry covalently linked fatty acids. Palmitoylation by ZDHHC2 regulates CD9 expression, association with other tetraspanin family proteins and function in cell adhesion. |
| Function | Integral membrane protein associated with integrins, which regulates different processes, such as sperm-egg fusion, platelet activation and aggregation, and cell adhesion. 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 CD9 and beta-1 and beta-2 integrins, and prevents macrophage fusion into multinucleated giant cells specialized in ingesting complement-opsonized large particles. 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. Regulates paranodal junction formation. Involved in cell adhesion, cell motility and tumor metastasis. Also regulates integrin-dependent migration of macrophages, particularly relevant for inflammatory response in the lung. |
| Protein Name | Cd9 AntigenCd Antigen Cd9 |
| Database Links | Reactome: R-MMU-114608Reactome: -MMU-1300645 |
| Cellular Localisation | Cell MembraneMulti-Pass Membrane ProteinMembraneSecretedExtracellular ExosomePresent At The Cell Surface Of OocytesAccumulates In The Adhesion Area Between The Sperm And Egg Following Interaction Between Izumo1 And Its Receptor Izumo1r/Juno |
| Alternative Protein Names | Cd9 Antigen proteinCd Antigen Cd9 proteinCd9 protein |
Information sourced from Uniprot.org
