FIGURE 1.

EXOs bud from endosome and plasma membranes. Exosome biogenesis may use three mechanisms: (1) vesicle budding into discrete endosomes that mature into multivesicular bodies, releasing EXOs upon plasma membrane fusion; (2) direct budding from plasma membrane and (3) delayed release by budding at intracellular plasma membrane–connected compartments (IPMCs) followed by deconstriction of IPMC neck(s). We note that this is not a comprehensive list and it is just to illustrate some of the mechanisms. Abbreviations: ECM, extracellular matrix; ERM, ezrin‐radixin‐moesin; ESCRTs, endosomal sorting complexes required for transport; MHC, major histocompatibility complex; IGSF8, immunoglobulin superfamily member 8; ICAM‐1, intercellular adhesion molecule‐1; SDC1, syndecans 1; HSPs, heat shock proteins