fig1

Figure 1. Biogenesis, structure, and action mode of the exosome. (A) Exosome formation is a function of endocytic membrane invagination and intraluminal vesicles (ILV) formation inside cells. Early maturation of endosomes leads to the formation of MVBs which are then delivered to lysosomes to be degraded or cross through microtubules to be combined with the plasma membrane and release exosomes into the extracellular space. (B) Exosomes contain various substances, such as mRNAs, miRNAs, proteins, enzymes, lipids, and carbohydrates. The exosome surface is decorated with various membrane proteins responsible for pathophysiological functions. (C) Exosomes facilitate communication between cells through three primary mechanisms. Signaling molecules act directly on the membrane's surface, regulate membrane fusion and its contents, and control the release of bioactive substances.