PRKN and Parkinson disease: The reduction in translation of vital proteins leads to neuronal death, which is rescued by inhibition of the pathway at the level of PERK3, 4, 5 or downstream effectors.6 In Parkinson's disease (PD), mitochondrial dysfunction, due to loss of function of PTEN-induced putative kinase 1 (PINK1) or PARKIN, is a central pathogenic process (reviewed in Celardo et al.7).