FIGURE 3.

Exosomal signaling through direct binding, membrane fusion, or endocytosis. (A) On reaching the target cells, molecules situated on the exosome's surface function as ligands, connecting to the receptors on the plasma membrane of the target cells, thus initiating an intracellular signaling cascade inside the recipient cell. (B) The exosome membrane fuses with the plasma membrane, thereby allowing the exosome contents to be released into the cytosol immediately. (C) The plasma membrane's deformational motion enables the transport of exosomes into the recipient cell, thereby activating signal transduction.