Auranofin targets UBA1 and enhances UBA1 activity by facilitating ubiquitin trans-thioesterification to E2 ubiquitin-conjugating enzymes

UBA1 is the primary E1 ubiquitin-activating enzyme responsible for generation of activated ubiquitin required for ubiquitination, a process that regulates stability and function of numerous proteins. Decreased or insufficient ubiquitination can cause or drive aging and many diseases. Therefore, a small-molecule enhancing UBA1 activity could have broad therapeutic potential. Here we report that auranofin, a drug approved for the treatment of rheumatoid arthritis, is a potent UBA1 activity enhancer. Auranofin binds to the UBA1's ubiquitin fold domain and conjugates to Cys1039 residue. The binding enhances UBA1 interactions with at least 20 different E2 ubiquitin-conjugating enzymes, facilitating ubiquitin charging to E2 and increasing the activities of seven representative E3s in vitro. Auranofin promotes ubiquitination and degradation of misfolded ER proteins during ER-associated degradation in cells at low nanomolar concentrations. It also facilitates outer mitochondrial membrane-associated degradation. These findings suggest that auranofin can serve as a much-needed tool for UBA1 research and therapeutic exploration. Decreased activity of the E1 ubiquitin-activating enzyme UBA1 can contribute to aging and diseases like Alzheimer's and VEXAS syndrome. Here, the authors found that auranofin, a rheumatoid arthritis drug, can significantly boost UBA1 activity.

Automated summary

UBA1 is a key enzyme in the ubiquitination process, and enhancing its activity with auranofin, a drug approved for rheumatoid arthritis, could have therapeutic potential. Auranofin binds to UBA1 and enhances its interaction with E2 enzymes, promoting ubiquitination.