Hypothetic mechanism of PINK1-Parkin mediated mitophagy according to the hypothesis raised by Narendra [20, 42]. The cellular mitochondria are governed by the quality control mechanism mitophagy, a form of autophagy in which defective mitochondria are selectively degraded by trafficking to lysosome. Left: PINK1 is a mitochondria located protein kinase with its enzymatic domain facing the cytosol. Expression of PINK1 on individual mitochondria is negatively regulated by Vdac1-dependent proteolysis to maintain low levels of PINK1 protein on intact mitochondria. Right: Loss of mitochondrial membrane potential (ΔΨm ⇓) leads to the accumulation of PINK1 on mitochondria. This gives Parkin the signal to recruit the PINK1-flagged mitochondria for mitophagy. This recruitment leads to the clearance of the defective organelle through the autophagosome formation.