Figure 2.

Prototypic vesicle. Although extracellular vesicles differ in size, composition and biogenesis, some basic characteristics can be summarized: Irrespective of the dimensions, EVs represent spherical, subcellular compartments that are composed of a phospholipid bilayer and various membrane-bound or plasmatic cargo molecules. Depending on the process during which they are released, the EV membrane retains the pattern of the cell surface they originated from. Given that EVs are released from all known tissue types, the maintained transmembrane molecules and phospholipids interact with countless cellular processes. The smaller EV fraction (which arises from the early endosome) and the multivesicular bodies display membrane features that resemble these cell organelles but are subject to fine-tuned wrapping mechanisms. In general, the EV content includes proteins/peptides, smaller metabolites, as well as nucleotide sequences.