OTUD5 Protects Dopaminergic Neurons by Promoting the Degradation of α-Synuclein in Parkinson's Disease Model

Defective clearance and accumulation of alpha-synuclein (alpha-Syn) is the key pathogenic factor in Parkinson's disease (PD). Recent studies emphasize the importance of E3 ligases in regulating the degradation of alpha-Syn. However, the molecular mechanisms by which deubiquitinases regulate alpha-Syn degradation are scarcely studied. In this study, it is found that the protein levels of alpha-Syn are negatively regulated by ovarian tumor protease deubiquitinase 5 (OTUD5) which protects dopaminergic (DA) neurons in the PD model. Mechanistically, OTUD5 promotes K63-linked polyubiquitination of alpha-Syn independent of its deubiquitinating enzyme activity and mediates its endolysosomal degradation by recruiting the E3 ligase neural precursor cell expressed developmentally downregulated 4 (NEDD4). Furthermore, OTUD5 conditional knockout in DA neurons results in more severe alpha-Syn related pathology and dyskinesia after injection of alpha-Syn preformed fibrils (PFF). Overall, the data unveil a novel mechanism to regulate the degradation of alpha-Syn and provide a new therapeutic strategy to alleviate DA neurodegeneration.