USP13 deubiquitinates p62/SQSTM1 to induce autophagy and Nrf2 release for activating antioxidant response genes

Area of Science:

• Molecular Biology
• Cell Biology
• Biochemistry

Background:

• SQSTM1/p62 is a key scaffold protein regulating selective autophagy and signaling pathways like mTORC1 and Keap1-Nrf2.
• Post-translational modifications, including ubiquitination, control p62's function, but its deubiquitination mechanisms are largely unknown.

Purpose of the Study:

• To investigate the deubiquitination of SQSTM1/p62 and identify the responsible enzyme.
• To elucidate the functional consequences of p62 deubiquitination on cellular processes and disease pathways.

Main Methods:

• Co-immunoprecipitation assays to identify USP13 binding to p62.
• In vitro deubiquitination assays to confirm USP13's enzymatic activity on p62.
• Western blotting and autophagy flux assays to assess p62 stability, oligomerization, and autophagic degradation.

Main Results:

• Ubiquitin-specific protease 13 (USP13) directly binds to SQSTM1/p62 and removes ubiquitin at Lys7 (K7) of the PB1 domain.
• USP13-mediated deubiquitination increases p62 protein stability and promotes its oligomerization.
• This process enhances autophagy and leads to the degradation of Keap1, thereby promoting Nrf2-mediated antioxidant response.

Conclusions:

• USP13 plays a critical role in regulating p62 stability and function through deubiquitination.
• USP13-mediated regulation of p62 impacts autophagy and the Keap1-Nrf2 antioxidant pathway.
• USP13 represents a potential therapeutic target for managing autophagy-related diseases.