Autophagy and Its Lineage-Specific Roles in the Hematopoietic System

Figure 1

Schematic representation of the different types of autophagy. Selective macroautophagy is a strictly regulated cytosolic cargo degradation pathway for the removal of excess ribosomes—ribophagy (a), intracellular pathogens—xenophagy (b), lipid droplets—lipophagy (c), superfluous protein aggregates—aggrephagy (d), polluted mitochondria—mitophagy (e), dispensable peroxisomes—pexophagy (f), and ferritin iron—ferritinophagy (g). Under stress, tumorigenesis, anticancer therapy, and nonselective macroautophagy are initiated with the isolation of the phagophore membrane, autophagosome formation, maturation, and degradation in the lysosome. Likewise, macroautophagy and microautophagy can be selective, while most microautophagy is the nonselective and bulk degradation of cargo molecules. Chaperone-mediated autophagy (CMA) is the translocation of the motif-bearing substrate molecules to the lysosomal membrane, whereas the lysosomal hydrolases degraded the proteins and release amino acids. During LAP, a common form of noncanonical macroautophagy, ATGs from the PIK3 complex, ATG5-ATG12, and LC3 conjugation system incorporated in phagolysosome formation and its degradation without the ULK1 complex autophagy.