Figure 4.

Autophagy. Unnecessary or damaged cellular material, including organelles, trapped in a nucleating endoplasmic reticulum (ER)-related membrane (phagophore) to form a closed vehicle (autophagosome) is delivered to lysosome, which fusions with autophagosome, giving autolysosme, in which the material is finally degraded and recycled. Basically, autophagy can proceed as an mTOR (mammalian target of rapamycin)-dependent, as presented in this figure, or -independent mechanism. Many proteins are involved in autophagy, including autophagy-related (ATG) proteins, Beclin-1, which suppresses ULK1 (Unc-51-like autophagy activating kinase 1) complex, and LC3 (microtubule-associated protein 1A/1B-light chain 3). Sharp arrows—activation, blunt arrows—inhibition, dashed short arrows—possible, not always occurring routes.