Figure 1. Schematic model of exosome origin and release.

Exosomes derived from the intraluminal vesicles (ILVs) of multivesicular bodies (MVBs), formed through the reversed budding of the membrane of late endosomes. ILVs encapsulate material from cytoplasm including RNA (both mRNAs and miRNAs) and proteins. Multivesicular bodies can fuse with lysosomes to degrade their content or fuse with the plasma membrane to release the ILVs into the extracellular space.