Fig. 1
From: The significance of exosomes in the development and treatment of hepatocellular carcinoma
a Biosynthesis of exosomes. Firstly, the inward budding of cell membrane forms early endosomes. Secondly, the multivesicular bodies (MVBs) are generated by further inward budding of endosomes and several miRNAs, proteins and other selected substances are incorporated. Finally, the MVBs either fuse with cell membrane, leading to inclusion of extracellular DNA, or fuse with lysosome, causing degradation of biological information containers of MVBs. The mechanism of the formation of exosomes is depicted in detail. b The concrete structure of the 4 kinds of ESCRT (ESCRT 0, I, II, and III0), and ALIX, a cytosolic protein, interacts with ESCRT-III subunit SNF7, finally combining with MVBs [33]