Fig. 2

Molecular pathways associated with Exo generation and release. An endosomal system composed of early, and late endosomes and multi-vesicular bodies (MVBs) plays a key role in the production of Exos. Inside the endosomes, numerous ILVs are formed by the invagination of the membrane. Upon secretion into the ECM, ILVs are named Exos. Different factors such as ESCRT complex (ESCRT-0, -I, -II, and -III) and tetraspanins sequestrate the signaling molecules into the ILVs. In the latter steps, the SNARE system in collaboration with several GTPases directs the MVBs toward the cell membrane to release the Exos