Aspirin inhibits proteasomal degradation and promotes protein aggregate clearance through K63 ubiquitination

Aspirin is a potent lysine acetylation inducer, but its impact on lysine ubiquitination and ubiquitination-directed protein degradation is unclear. Herein, we developed the reversed-pulsed-SILAC strategy to systematically profile protein degradome in response to aspirin. By integrating degradome, acetylome, and ubiquitinome analyses, we showed that aspirin impairs proteasome activity to inhibit proteasomal degradation, rather than directly suppressing lysine ubiquitination. Interestingly, aspirin increases lysosomal degradation-implicated K63-linked ubiquitination. Accordingly, we found that aspirin is able to reduce a-syn aggregates, the major pathologic protein of Parkinson's disease, in cultured cells, neurons, and PD model mice with a rescued locomotor ability. We further revealed that the a-syn aggregate clearance induced by aspirin is K63-ubiquitination dependent in both cells and PD mice. These findings suggest two complementary mechanisms by which aspirin regulates the degradation of soluble and insoluble proteins, providing new insights into its diverse pharmacological effects that can aid in future drug development efforts.