Fig. 1

Overview of the process for exosome biogenesis. MVBs take the center of exosome biogenesis. Generally, MVBs are derived from endocytosis, during which different mechanisms mediate the inward budding of the plasma membrane and the formation of early endosomes. MVBs can dynamically communicate with other organelles or compartments including trans-Golgi network (TGN), endoplasmic reticulum (ER), mitochondrion, phagosome, RNA granule and micronuclei, et al. Therefore, different repertoires of cargos such as proteins, RNAs, DNAs or lipids are sorted into MVBs. After the maturation of MVBs, they can either fuse with lysosome to be degraded or fuse with plasma membrane to release ILVs, the so-called exosomes. Of note, MVB can fuse with autophagosome to form amphisome, which can either fuse with lysosome to be degraded or fuse with plasma membrane to secret exosomes