The Physiological Role of Mitophagy: New Insights into Phosphorylation Events

Figure 1

Mitophagy in yeast. Environmental or intracellular factors trigger the mitophagy-signaling pathways that include two MAPKs (Slt2 and Hog1), finally reaching and activating an unidentified kinase X. This kinase phosphorylates Ser114 and Ser119 on Atg32. Phosphorylation of Atg32, particularly at Ser114, mediates the Atg11–Atg32 interaction. Atg11 recruits mitochondria to the phagophore assembly site (PAS) where the autophagosome is generated to enclose the mitochondria. The antioxidant compound N-acetylcysteine (NAC) inhibits mitophagy, presumably by suppressing Atg32 expression. The Atg32–Atg8 interaction increases the efficiency of mitochondrial sequestration by the isolation membrane. Atg33, Whi2, Uth1, and Aup1 have been reported to be required for mitophagy. However, the function of these proteins in mitophagy has not been identified.