PARK7 and Parkinson disease: Remarkably, DJ-1 (MIM 602533), implicated in early-onset Parkinson’s disease (PARK7, MIM #606324), in the aetiology of which the UPS is involved [20,21], as well as Apolipoprotein B mRNA-editing Enzyme, Catalytic Polypeptide 2 (APOBEC2) required for zebrafish retina regeneration are among the SUMOylation substrates of TOPORS [22,23], further supporting the role for the UPS in neuronal and retinal homeostasis.