Fig. 1

The molecular mechanisms of exosomal biogenesis and metabolism: ESCRT-0 first recognizes ubiquitinated cargo; ESCRT-I and ESCRT-II complexes form an ESCRT-cargo-enriched zone; ESCRT-III recruits deubiquitination machinery and packages cargo into maturing vesicles and promotes vesicle budding. Next, these inward buds form early endosomes and further mature into MVBs. Rap5 and Rap7 promote the development of MVBs from early endosomes. Rab27A and Rab27B induce the translocation of MVBs to the cell periphery, and then the SNARE complex mediates membrane fusion between MVBs and the plasma membrane to release exosomes. A deubiquitinating enzyme suppresses the degradation of MVBs in the lysosome