Figure 1.

The feature of autophagy. Autophagy involves the formation of autophagosomes, their fusion with lysosomes and subsequent degradation of autophagolysosomal contents. The formation of phagophore is depending on the interactions between lipid bilayers and recruited ULK complex (composed of Atg13, Atg101, ULK1 and FIP200) and PI3K complex (composed of Atg14, Beclin-1, VPS34 and VPS15). At the same time, two different conjugation systems, LC3 and the complex of Atg12-Atg5-Atg16L are involved in the assembling of autophagosome. After devouring damaged proteins and organelles, mature autophagosome fuses with lysosome to form autolysosome. Finally, the inner contents are degraded by lysosomal hydrolases and released as nutrients and metabolites. Atg: autophagy-related gene; LC3: Light chain 3.