PRKN and Parkinson disease: Proteins harboring those mutations include ubiquilin‐1, leading to presenilin aggregation (mutated in some familial AD) (Viswanathan et al., 2011); ubiquilin‐2 which also targets ubiquitinylated proteins to proteasomes (mutated in ALS) (Zhang et al., 2014); and parkin, an E3 ubiquitin ligase required for mono‐ubiquitin addition to specific protein targets (mutated in PD) (Roy et al., 2015).