Beclin 1 Complex and Neurodegenerative Disorders

Molecular Mechanisms Of Autophagy

Autophagy can be described as an intracellular biochemical process of catabolic nature that facilitates degradation and removal of dysfunctional proteins, damaged organelles, unutilized biological macromolecules, and invaded pathogens or foreign biological materials present within the cytoplasm of a cell through an autophagosome-lysosomal pathway. It functions as a survival mechanism against various kinds of stress such as starvation, during which unwanted cytoplasmic material is recycled and adenosine triphosphate (ATP) molecules are synthesized and also as a defense system against pathogenic microorganisms and cellular debris (Mizushima et al., 2011) as shown in Figure 1. Based on the mechanisms utilized for transporting cargo to lysosomes, three different autophagy processes were reported in the literature (Figure 2); macroautophagy, microautophagy and chaperone-mediated autophagy (CMA). Macroautophagy also called autophagy is the basic pathway utilized by cells for degrading cytoplasmic organelles and malformed proteins (Deretic et al., 2018).

Figure 1.

Roles of autophagy in biological systems.

Figure 2.

Different types of autophagy in mammalian cells.