期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2022
卷号：119
期号：36
DOI：10.1073/pnas.2205608119
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance
The deneddylase Cop9 signalosome (CSN) regulates the function of cullin-RING ubiquitin ligases (CRLs), which are involved in regulating myriad cellular functions through the ubiquitin-mediated degradation of proteins such as transcription factors, cell cycle regulators, and signal transduction proteins. CSN inhibition by the small molecule inhibitor, CSN5i-3, has differential effects on CRL function. Some CRLs are profoundly inactivated when CSN is inhibited, whereas others are barely affected. Therefore, it is difficult to deconvolute the effects of CSN inhibition on cells. To untangle this, we used CRISPRi and CRISPRa screens and identified two contributing pathways involved in DNA replication licensing. The knowledge can potentially be used to guide selection of cancer patients that are most likely to respond to CSN5i-3.
Cop9 signalosome (CSN) regulates the function of cullin–RING E3 ubiquitin ligases (CRLs) by deconjugating the ubiquitin-like protein NEDD8 from the cullin subunit. To understand the physiological impact of CSN function on the CRL network and cell proliferation, we combined quantitative mass spectrometry and genome-wide CRISPR interference (CRISPRi) and CRISPR activation (CRISPRa) screens to identify factors that modulate cell viability upon inhibition of CSN by the small molecule CSN5i-3. CRL components and regulators strongly modulated the antiproliferative effects of CSN5i-3, and in addition we found two pathways involved in genome integrity, SCF
FBXO5–APC/C–GMNN and CUL4
DTL–SETD8, that contribute substantially to the toxicity of CSN inhibition. Our data highlight the importance of CSN-mediated NEDD8 deconjugation and adaptive exchange of CRL substrate receptors in sustaining CRL function and suggest approaches for leveraging CSN inhibition for the treatment of cancer.
