Regulation of Claspin degradation by the ubiquitin-proteosome pathway during the cell cycle and in response to ATR-dependent checkpoint activation

FEBS Lett. 2006 Jul 24;580(17):4176-81. doi: 10.1016/j.febslet.2006.06.071. Epub 2006 Jul 5.

Abstract

Claspin is involved in ATR-dependent activation of Chk1 during DNA replication and in response to DNA damage. We show that degradation of Claspin by the ubiquitin-proteosome pathway is regulated during the cell cycle. Claspin is stabilized in S-phase but is abruptly degraded in mitosis and is absent from early G(1) cells in which the phosphorylation of Chk1 by ATR is abrogated. In response to hydroxyurea, UV or aphidicolin, Claspin is phosphorylated in the Chk1-binding domain and its protein levels are increased in an ATR-dependent manner. Thus, the Chk1 pathway is regulated through both phosphorylation of Claspin and its controlled degradation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism*
  • Antineoplastic Agents / pharmacology
  • Aphidicolin / pharmacology
  • Ataxia Telangiectasia Mutated Proteins
  • Cell Cycle Proteins / metabolism*
  • Cell Line, Tumor
  • Checkpoint Kinase 1
  • Enzyme Inhibitors / pharmacology
  • G1 Phase* / drug effects
  • G1 Phase* / radiation effects
  • Humans
  • Hydroxyurea / pharmacology
  • Mitosis / drug effects
  • Mitosis / radiation effects
  • Phosphorylation / drug effects
  • Phosphorylation / radiation effects
  • Proteasome Endopeptidase Complex / metabolism*
  • Protein Kinases / metabolism
  • Protein Processing, Post-Translational / drug effects
  • Protein Processing, Post-Translational / radiation effects
  • Protein-Serine-Threonine Kinases / metabolism*
  • S Phase* / drug effects
  • S Phase* / radiation effects
  • Signal Transduction / drug effects
  • Signal Transduction / radiation effects
  • Ubiquitin / metabolism*
  • Ultraviolet Rays

Substances

  • Adaptor Proteins, Signal Transducing
  • Antineoplastic Agents
  • CLSPN protein, human
  • Cell Cycle Proteins
  • Enzyme Inhibitors
  • Ubiquitin
  • Aphidicolin
  • Protein Kinases
  • ATR protein, human
  • Ataxia Telangiectasia Mutated Proteins
  • CHEK1 protein, human
  • Checkpoint Kinase 1
  • Protein-Serine-Threonine Kinases
  • Proteasome Endopeptidase Complex
  • Hydroxyurea