Autophagy is a natural, intracellular, and conserved degradation system that is lysosome-dependent, and is able to remove unnecessary or dysfunctional components. It plays a key role in a wide variety of physiological and pathophysiological processes. Defects in autophagy have been linked to various human diseases, such as neurodegeneration and cancer, and interest in modulating autophagy as a potential treatment for these diseases has grown rapidly. Autophagy signal pathways are mainly regulated by autophagy-related genes or proteins, e.g. ATGs. ATGs have unveiled much of the machinery of autophagosome formation. Furthermore, different non-ATG proteins are involved in the regulation and process of autophagy, e.g. AKT, AMPK, mTOR, AMBRA1, BCL2, DFCP1, or VPS34.