FIGURE 2.

Lipids in exosome biogenesis. Membrane domains enriched in cholesterol appear to provide adequate conditions for the recruitment of ESCRT machinery in MVBs. Ceramide and phosphatidic acid are cone‐shaped lipids that seem to induce spontaneous curvature of the MVBs membrane in an ESCRT‐independent manner. Ceramide is produced from sphingomyelin through the activity of the sphingomyelinases (SMase). On their part, phosphatidic acid is produced from phosphatidylcholine and diacylglycerol through the activity of the phospholipases (PLase) and diacylglycerol kinases (DGK), respectively. Furthermore, phosphatidic acid seems to interact with syndecan to enhance the recruitment of syntenin (Syn), ALIX and the ESCRT machinery