PRKN and Parkinson disease: Intriguingly, several studies reported Parkin inactivation by structural modification such as S-nitrosylation (Chung et al., 2004), phosphorylation (Ko et al., 2010), and dopamine (LaVoie et al., 2005) in sporadic PD brains, suggesting the broader involvement of Parkin and impaired mitophagy in the pathogenesis of PD.