PRKN and Alzheimer disease: The levels of PARKIN, which is E3 ubiquitin ligase and required to initiate the mitophagy, were found to be reduced in the cytoplasm of AD patient brains along with abnormal PINK1 accumulation, leading the defective mitophagy, which in turn can be resorted by overexpressing PARKIN (Martín-Maestro et al., 2016).