FIGURE 1.

Schematic diagram of the biogenesis and secretion of exosomes, and their function ways to the recipient cell. Donor cell plasma membrane invaginate through endocytosis to form early endosome, which subsequently develop into late endosome via endosomal membrane budding inward to form intraluminal vesicles (ILVs). The late endosome constantly buds inward and form ILVs, which keep accumulating and constitute multivesicular body (MVB). MVB can either be degraded by lysosome or fuse with the plasma membrane to permit the ILVs to be released into the extracellular environment through exocytosis as exosomes. Exosomes mediate their effects on the recipient cells through three main manners: (A) receptor mediated signal amplification, (B) endocytosis, and (C) membrane fusion.