RESUMEN
The human ubiquitin proteasome system, composed of over 700 ubiquitin ligases (E3s) and deubiquitinases (DUBs), has been difficult to characterize systematically and phenotypically. We performed chemical-genetic CRISPR-Cas9 screens to identify E3s/DUBs whose loss renders cells sensitive or resistant to 41 compounds targeting a broad range of biological processes, including cell cycle progression, genome stability, metabolism, and vesicular transport. Genes and compounds clustered functionally, with inhibitors of related pathways interacting similarly with E3s/DUBs. Some genes, such as FBXW7, showed interactions with many of the compounds. Others, such as RNF25 and FBXO42, showed interactions primarily with a single compound (methyl methanesulfonate for RNF25) or a set of related compounds (the mitotic cluster for FBXO42). Mutation of several E3s with sensitivity to mitotic inhibitors led to increased aberrant mitoses, suggesting a role for these genes in cell cycle regulation. Our comprehensive CRISPR-Cas9 screen uncovered 466 gene-compound interactions covering 25% of the interrogated E3s/DUBs.