CD63

By Jamshed Arslan, Pharm. D., PhD.

Exosomes are spherical to cup-shaped bilayered membrane enclosed nanosize vesicles (30-100 nm) which have the ability to shuttle active cargoes between cells. Johnstone et al. 1987 pioneered in documenting the generation of exosomes in differentiating reticulocytes as a result of the fusion of multi-vesicular endosomes/MVBs with the plasma membrane.

CD63 is a type II membrane protein belonging to tetraspanin superfamily and it play key roles in the activation of several cellular signaling cascades along with acting as TIMP1 receptor. It is expressed by activated platelets, monocytes, macrophages, granulocytes, T /B cells, and different type of cancer cells. CD63 localizes to endosomes, lysosomes and on the cellular surfaces, and is often considered as a marker for late endosomes as well as for lysosomes.