PRKN and Parkinson disease: PINK1 loss-of-function mutant phenotypes can be rescued by antioxidants; overexpression of Parkin (a ubiquitin E3 ligase) as well as transgenic expression of the anti-apoptotic protein Bcl-2— one of the most potent inhibitors of MMP [3–6]—indicate the existence of a pathway that links most of the proteins that when defective cause PD.