The biogenesis of Extracellular Vesicles (EVs). Extracellular vesicles are membrane vesicles from various origins. Recently, EVs are classified into two distinct groups-exosomes and microvesicles. Microvesicles are formed by budding of plasma membrane and exosomes are generated from intraluminal vesicles within the lumen of multivesicular body (MVB) that are sequentially fused with the plasma membrane. Several proteins are implicated in exosome biogenesis such as Rab GTPases, ESCRT proteins, and other proteins that are also used as markers for exosomes (e.g. tetraspanins, TSG101, Alix). Exosomes include tetraspanins (e.g. CD63, CD81, CD9), MHC complex, transmembrane receptor, and adhesion proteins in their surface. It has been reported that exosomes contain different types of intracellular proteins, DNA, and RNA including non-coding RNAs (ncRNA).
