Figure 4.

Biogenesis of exosomes. (1) Internalized cargo from the cellular membrane via endocytosis is sorted into (2) early endosomes. (3) ESCRT, tetraspanins, and lipids guide early endosomes through late endosome/MVB maturation, (4) which is concentrated with ILVs. (5) The Golgi apparatus then supplements ILVs with nucleic acids, RNAs, proteins, and MHC II molecules. (6) MVBs are then transported to the plasma membrane via the cytoskeletal and microtubule network. (7) During the transportation process, Rab GTPases guide the docking and fusion of MVB with the plasma membrane. (8) ILVs are secreted as exosomes via exocytosis.