USP7 limits CDK1 activity throughout the cell cycle

EMBO J. 2021 Jun 1;40(11):e99692. doi: 10.15252/embj.201899692. Epub 2021 Apr 15.


Chemical inhibitors of the deubiquitinase USP7 are currently being developed as anticancer agents based on their capacity to stabilize P53. Regardless of this activity, USP7 inhibitors also generate DNA damage in a p53-independent manner. However, the mechanism of this genotoxicity and its contribution to the anticancer effects of USP7 inhibitors are still under debate. Here we show that, surprisingly, even if USP7 inhibitors stop DNA replication, they also induce a widespread activation of CDK1 throughout the cell cycle, which leads to DNA damage and is toxic for mammalian cells. In addition, USP7 interacts with the phosphatase PP2A and supports its active localization in the cytoplasm. Accordingly, inhibition of USP7 or PP2A triggers very similar changes of the phosphoproteome, including a widespread increase in the phosphorylation of CDK1 targets. Importantly, the toxicity of USP7 inhibitors is alleviated by lowering CDK1 activity or by chemical activation of PP2A. Our work reveals that USP7 limits CDK1 activity at all cell cycle stages, providing a novel mechanism that explains the toxicity of USP7 inhibitors through untimely activation of CDK1.

Keywords: CDK1; USP7; anticancer drugs; cell cycle; deubiquitinase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CDC2 Protein Kinase / metabolism*
  • Cell Cycle*
  • Cells, Cultured
  • DNA Damage
  • HCT116 Cells
  • Humans
  • Mice
  • NIH 3T3 Cells
  • Protease Inhibitors / toxicity
  • Protein Phosphatase 2 / metabolism
  • Protein Transport
  • Ubiquitin-Specific Peptidase 7 / antagonists & inhibitors
  • Ubiquitin-Specific Peptidase 7 / metabolism*


  • Protease Inhibitors
  • CDC2 Protein Kinase
  • CDK1 protein, human
  • Protein Phosphatase 2
  • USP7 protein, human
  • Ubiquitin-Specific Peptidase 7