Human CD63 antigen, also referred to as Granulophysin, Lysomal-associated membrane protein 3 (LAMP-3), Tetraspanin-30, and Ocular melanoma-associated antigen, is a membrane bound protein encoded by the gene CD63. CD63 belongs to a group of proteins known as the tetraspanin family, which are characterized by the presence of four hydrophobic domains and are found to mediate signal transduction events for the regulation of cell development, activation, growth, and motility. Deficiency of this protein is associated with Hermansky-Pudlak Syndrome, which is an autosomal disorder.