Exosome release by reticulocytes—An integral part of the red blood cell differentiation system

Reticulocyte maturation into erythrocytes is the final step of erythropoiesis that occurs in the blood circulation. This terminal differentiation period corresponds to a cellular remodeling phase following expulsion of the nucleus into the bone marrow. Among other events, this remodeling leads to the disappearance of intracellular organelles and acquisition of the typical cellular biconcave form. Here, we propose that exosome biogenesis and secretion, which contributes to net loss of the cell surface membrane via selective vesicular membrane secretion, is also closely interconnected with upstream (nucleus expulsion), accompanying (mitoptosis) and downstream (vesicle clearance) events.