| Description | CD63 is not only expressed on activated platelets, but also activated monocytes and macrophages, and is weakly expressed on granulocytes, T cell and B cells. It is located on the basophilic granule membranes and translocated to cell surface upon various stimuli. The membrane of lytic granules in CTLs contains CD63/LAMP-3 and other lysosomal-associated glycoproteins (LAMPs) such as CD107a/LAMP-1 and CD107b/LAMP-2. LAMPs have b een observed on the cell surface as a result of degranulation. CD63 belongs to a member of the tetraspanin transmembrane-protein (TM4) superfamily, which includes CD9, CD37, CD53, CD81, CD82, CD151 and CD231. Several members of this family form noncovalent associations with integrins, particularly β 1 integrins (CD29), and modulate cellular adhesion properties. CD63 has a tyrosine-based internalization motif in the cytoplasmic C-terminal tail and interacts with adaptor protein complexes such as AP-2 and AP-3. Because AP-2 and AP-3 are involved in facilitating the clathrin-mediated endocytosis, CD63 could be directly involved in the internalization of its membrane protein partners.Synonyms: Granulophysin, ME491, MLA1, Melanoma-associated antigen ME491, OMA81H, Ocular melanoma-associated antigen, TSPAN30, Tetraspanin-30 |
|---|