SCFbetaTrCP-mediated degradation of Claspin regulates recovery from the DNA replication checkpoint response

Mol Cell. 2006 Aug 4;23(3):319-29. doi: 10.1016/j.molcel.2006.06.013.


During replicative stress, Claspin mediates the phosphorylation and consequent activation of Chk1 by ATR. We found that during recovery from the DNA replication checkpoint response, Claspin is degraded in a betaTrCP-dependent manner. In vivo, Claspin is phosphorylated in a canonical DSGxxS degron sequence, which is typical of betaTrCP substrates. Phosphorylation of Claspin is mediated by Plk1 and is essential for binding to betaTrCP. In vitro ubiquitylation of Claspin requires betaTrCP, Plk1, and an intact DSGxxS degron. Significantly, expression of a stable Claspin mutant unable to bind betaTrCP prolongs the activation of Chk1, thereby attenuating the recovery from the DNA replication stress response and significantly delaying entry into mitosis. Thus, the SCFbetaTrCP-dependent degradation of Claspin is necessary for the efficient and timely termination of the DNA replication checkpoint. Importantly, in response to DNA damage in G2, Claspin proteolysis is inhibited to allow the prompt reestablishment of the checkpoint.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / physiology*
  • Amino Acid Sequence
  • Binding Sites / genetics
  • Cell Cycle / drug effects
  • Cell Cycle / physiology
  • Cell Cycle / radiation effects
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Cell Line
  • Cell Line, Tumor
  • DNA Damage / physiology
  • DNA Replication / drug effects
  • DNA Replication / physiology*
  • DNA Replication / radiation effects
  • Histones / metabolism
  • Humans
  • Hydroxyurea / pharmacology
  • Models, Biological
  • Mutation / genetics
  • Phosphorylation / drug effects
  • Protein Binding
  • RNA, Small Interfering / genetics
  • SKP Cullin F-Box Protein Ligases / genetics
  • SKP Cullin F-Box Protein Ligases / metabolism*
  • Sequence Homology, Amino Acid
  • Transfection
  • Ubiquitin / metabolism
  • Ultraviolet Rays


  • Adaptor Proteins, Signal Transducing
  • CLSPN protein, human
  • Cell Cycle Proteins
  • Histones
  • RNA, Small Interfering
  • Ubiquitin
  • SKP Cullin F-Box Protein Ligases
  • Hydroxyurea