Figure 6.

Molecular signaling pathways regulating autophagy. Autophagy is mediated by a double-membrane special organelle termed autophagosome that, upon induction, fuses with a lysosome to form an autolysosome, leading to the degradation of the enclosed materials. The central signaling molecule in determining the levels of autophagy in cells is the mTOR kinase that is recognized as sensor that coordinately regulates the balance between growth and autophagy in response to cellular physiological conditions and environmental stress and likely mediates its effects on autophagy through inhibition of ATG1/ULK-1/-2 complexes at the earliest stages in phagophore formation from lipid bilayers.