PRKN and Parkinson disease: They further revealed that the overexpression of Parkin could ameliorate the MPTP-induced mitochondrial impairment in the substantia nigra of Parkin transgenic mice, reducing striatal α-synuclein protein in old Parkin transgenic mice, thereby protecting dopaminergic neurons against neurodegeneration induced by MPTP.167 The finding provided complicated cellular and molecular mechanisms involved in the neuroprotection of Parkin in the mice model of PD.