Mutation of aspartic acid 199 in USP1 disrupts its deubiquitinating activity and impairs DNA repair

The deubiquitinating enzyme USP1 contains highly conserved motifs forming its catalytic center. Recently, the COSMIC mutation database identified a in at Asp-199 endometrial cancer. Here, we investigated role of for function. aspartic acid to alanine (D199A) resulted failure undergo autocleavage and form complex with ubiquitin, indicating D199A Usp1 is catalytically inactive. did not affect interaction Uaf1. Moreover, had defects deubiquitination FANCD2 PCNA displayed reduced foci formation DNA repair efficiency. Furthermore, glutamic phenotypes similar mutation. Collectively, our findings demonstrate importance activity suggest implications downregulation