PINK1 and Parkinson disease: Recent cell-based and in vivo studies have revealed that PINK1 acts upstream of another gene product that is relevant to Parkinson's disease, Parkin (Clark et al., 2006; Geisler et al., 2010; Kitada et al., 1998; Matsuda et al., 2010; Narendra et al., 2010; Park et al., 2006; Rakovic et al., 2010; Vives-Bauza et al., 2010; Yang et al., 2006; Ziviani et al., 2010).