DNA Replication Determines Timing of Mitosis by Restricting CDK1 and PLK1 Activation

Mol Cell. 2018 Jul 5;71(1):117-128.e3. doi: 10.1016/j.molcel.2018.05.026. Epub 2018 Jun 28.


To maintain genome stability, cells need to replicate their DNA before dividing. Upon completion of bulk DNA synthesis, the mitotic kinases CDK1 and PLK1 become active and drive entry into mitosis. Here, we have tested the hypothesis that DNA replication determines the timing of mitotic kinase activation. Using an optimized double-degron system, together with kinase inhibitors to enforce tight inhibition of key proteins, we find that human cells unable to initiate DNA replication prematurely enter mitosis. Preventing DNA replication licensing and/or firing causes prompt activation of CDK1 and PLK1 in S phase. In the presence of DNA replication, inhibition of CHK1 and p38 leads to premature activation of mitotic kinases, which induces severe replication stress. Our results demonstrate that, rather than merely a cell cycle output, DNA replication is an integral signaling component that restricts activation of mitotic kinases. DNA replication thus functions as a brake that determines cell cycle duration.

Keywords: CDK1; DNA replication; G2 phase; PLK1; S phase; cell cycle; mitosis; replication checkpoint.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CDC2 Protein Kinase / genetics
  • CDC2 Protein Kinase / metabolism*
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cell Line, Tumor
  • Checkpoint Kinase 1 / genetics
  • Checkpoint Kinase 1 / metabolism
  • Enzyme Activation
  • Humans
  • Mitosis*
  • Polo-Like Kinase 1
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism*
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • S Phase*
  • p38 Mitogen-Activated Protein Kinases / genetics
  • p38 Mitogen-Activated Protein Kinases / metabolism


  • Cell Cycle Proteins
  • Proto-Oncogene Proteins
  • CHEK1 protein, human
  • Checkpoint Kinase 1
  • Protein Serine-Threonine Kinases
  • CDC2 Protein Kinase
  • CDK1 protein, human
  • p38 Mitogen-Activated Protein Kinases