Cdc2 phosphorylation of Crb2 is required for reestablishing cell cycle progression after the damage checkpoint.
DNA damage induces cell cycle arrest (called the damage checkpoint), during which cells carry out actions for repair. A fission yeast protein, Crb2/Rhp9, which resembles budding yeast Rad9p and human BRCA1, promotes checkpoint by activating Chk1 kinase, which restrains Cdc2 activation. We show here that phosphorylation of the T215 Cdc2 site of Crb2 is required for reentering the cell cycle after the damage-induced checkpoint arrest. If this site is nonphosphorylatable, irradiated cells remain arrested, though damage is repaired, and maintain the phosphorylated state of Chk1 kinase. The T215 site is in vitro phosphorylated by purified Cdc2 kinase. Phosphorylation of T215 occurs intensely in response to DNA damage at a late stage, suggesting an antagonistic role of Cdc2 phosphorylation toward checkpoint.
Esashi
F
F
CREST Research Project, Department of Biophysics, Graduate School of Science, Kyoto University, Japan.
Yanagida
M
M
D019313:BRCA1 Protein / Q000378:metabolism; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000071877:Checkpoint Kinase 1; D004249:DNA Damage; D005656:Fungal Proteins / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012568:Schizosaccharomyces / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins
D019313:BRCA1 Protein; D018797:Cell Cycle Proteins; C109867:Crb2 protein, S pombe; D005656:Fungal Proteins; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D029702:Schizosaccharomyces pombe Proteins; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; C000605873:Chk1 protein, S pombe; D016203:CDC2 Protein Kinase