Autophagy

Autophagy is an intracellular catabolic mechanism. In certain stressful situations, lysosomes degrade degenerated, damaged, aged or non-functional cells, organelles and biomolecules such as proteins and nucleic acids to achieve cellular protection and organelles from cell damage. Autophagy is achieved by forming a bilayer membrane structure in the cytoplasm that wraps the material to be removed and transports it to the lysosome for degradation. In multicellular organisms, newly formed autophagic vesicles form autophagic endosomes by fusing with vesicles in different stages of the endocytic lysosomal pathway, such as early endosomes and late endosomes, before fusing with lysosomes, a process known as autophagic vesicle maturation. Abnormalities in autophagosome maturation, which is precisely regulated by cellular trophic state and stress signaling pathways, lead to the accumulation of large amounts of damaged organelles and toxic protein aggregates in cells.