Fig. 3.

Exosome biogenesis. Within the endosomal system, [1] internalised cargoes are [2] sorted into early endosomes, [3] which then mature into late endosomes or multivesicular bodies. Late endosomes/multivesicular bodies are specialised endosomal compartments rich in intraluminal vesicles (ILVs), which sequester proteins, lipids, and cytosolic compartments and potential exosome cargoes. [4] Cargoes are also delivered from trans-Golgi network and possibly from cytosol. [5] Multivesicular bodies containing exosome cargoes get [5] transported to the plasma membrane, [6] fuse with the cell surface and [7] the ILVs then get secreted as exosomes. ER: Endoplasmic Reticulum; MVB: Multivesicular Bodies; PM: Plasma membrane