PRKN and Parkinson disease: We also examined the effects of mitochondrial and cellular stress, in part because the PINK1/Parkin mitochondrial stress response pathway is strongly implicated in PD.87 Both treatment with the ionophore CCCP and mild permeabilization of the plasma membrane by digitonin substantially increases co-localization of low expression a-syn with mitochondria, and co-localized a-syn is distinct from the mitochondrial matrix as visualized with super-resolution imaging (Fig. 7g).