ATP-dependent activation of p21WAF1/CIP1-associated Cdk2 by Cdc6

Proc Natl Acad Sci U S A. 2008 Mar 25;105(12):4757-62. doi: 10.1073/pnas.0706392105. Epub 2008 Mar 20.

Abstract

When cells progressing in mid-S phase are damaged with a base-modifying chemical, they arrest in S phase long after the CHK1 checkpoint signal fades out, partly because of p53-mediated long-lasting induction of the cyclin-dependent kinase inhibitor p21(WAF1/CIP1). We have recently found that enforced expression of Cdc6, the assembler of prereplicative complexes, markedly advances recovery from the prolonged S-phase arrest and reactivation of Cdk2 despite the presence of a high level of induced p21. Here, we report that Cdc6 protein can activate p21-associated Cdk2 in an ATP-dependent manner in vitro. Consistently, Cdc6 mutated for ATPase or a putative cyclin binding motif is no longer able to activate the Cdk2 in vitro or promote reinitiation of S-phase progression and reactivation of Cdk2 in vivo. These results reveal the never anticipated function of Cdc6 and redefine its role in the control of S-phase progression in mammalian cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / metabolism
  • Adenosine Triphosphate / pharmacology*
  • Amino Acid Motifs
  • Animals
  • Cell Cycle Proteins / chemistry
  • Cell Cycle Proteins / metabolism*
  • Chromosomal Proteins, Non-Histone / chemistry
  • Chromosomal Proteins, Non-Histone / metabolism*
  • Cyclin-Dependent Kinase 2 / metabolism*
  • Cyclin-Dependent Kinase Inhibitor p21 / metabolism*
  • Cyclin-Dependent Kinase Inhibitor p27 / metabolism
  • Cyclins / metabolism
  • Enzyme Activation / drug effects
  • Methyl Methanesulfonate / pharmacology
  • Mice
  • Mutation / genetics
  • Protein Binding / drug effects
  • Rats
  • S Phase / drug effects

Substances

  • Cdc6 protein, rat
  • Cell Cycle Proteins
  • Chromosomal Proteins, Non-Histone
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins
  • Cyclin-Dependent Kinase Inhibitor p27
  • Adenosine Triphosphate
  • Methyl Methanesulfonate
  • Cyclin-Dependent Kinase 2
  • Adenosine Triphosphatases