8.A.40.1.19
Antigen CD63 of 238 aas and 4 TMSs.  It functions as cell surface receptor, and plays a role in the activation of cellular signaling cascades.  It also plays a role in intracellular and extracellular vesicular transport processes, and is required for normal trafficking that is essential for the development and maturation of melanocytes (van Niel et al. 2011; Lee et al. 2014). CD63 is on natural exosomes (cell derived extracellular vesicles), and it is highly enriched on the external surfaces of these membranes (Curley et al. 2020). Distinct scaffolds based on engineering of CD63 enable flexible engineering of the exosome surface for applications in disease-targeted drug delivery and therapy. CD63 proximal interacting proteins comprise the network of partners required for endocytic trafficking and extracellular vesicle cargo sorting, formation, and secretion (Cheerathodi et al. 2021). Climbazole and heparin undermine membrane-bound tetraspanin CD63 expression, significantly disrupted ALIX protein, and alter human carcinoma lung cell-derived extracellular vesicle formation (Ipinmoroti et al. 2023). CD63 also participates in extracellular vesicle loading and delivery (Bui et al. 2023); see also TC Family 1.F.4.