RRC ID 30561
Author Mahyous Saeyd SA, Ewert-Krzemieniewska K, Liu B, Caspari T.
Title Hyperactive Cdc2 kinase interferes with the response to broken replication forks by trapping S.pombe Crb2 in its mitotic T215 phosphorylated state.
Journal Nucleic Acids Res.
Abstract Although it is well established that Cdc2 kinase phosphorylates the DNA damage checkpoint protein Crb2(53BP1) in mitosis, the full impact of this modification is still unclear. The Tudor-BRCT domain protein Crb2 binds to modified histones at DNA lesions to mediate the activation of Chk1 by Rad3ATR kinase. We demonstrate here that fission yeast cells harbouring a hyperactive Cdc2CDK1 mutation (cdc2.1w) are specifically sensitive to the topoisomerase 1 inhibitor camptothecin (CPT) which breaks DNA replication forks. Unlike wild-type cells, which delay only briefly in CPT medium by activating Chk1 kinase, cdc2.1w cells bypass Chk1 to enter an extended cell-cycle arrest which depends on Cds1 kinase. Intriguingly, the ability to bypass Chk1 requires the mitotic Cdc2 phosphorylation site Crb2-T215. This implies that the presence of the mitotic phosphorylation at Crb2-T215 channels Rad3 activity towards Cds1 instead of Chk1 when forks break in S phase. We also provide evidence that hyperactive Cdc2.1w locks cells in a G1-like DNA repair mode which favours non-homologous end joining over interchromosomal recombination. Taken together, our data support a model such that elevated Cdc2 activity delays the transition of Crb2 from its G1 to its G2 mode by blocking Srs2 DNA helicase and Casein Kinase 1 (Hhp1).
Volume 42(12)
Pages 7734-47
Published 2014-7
DOI 10.1093/nar/gku452
PII gku452
PMID 24861625
PMC PMC4081076
MeSH Antigens, Nuclear / metabolism CDC2 Protein Kinase / genetics CDC2 Protein Kinase / metabolism* Camptothecin / pharmacology Cell Cycle Proteins / chemistry Cell Cycle Proteins / metabolism* Checkpoint Kinase 1 DNA Helicases / metabolism DNA Repair* DNA Replication DNA-Binding Proteins / metabolism G1 Phase / genetics G2 Phase Cell Cycle Checkpoints / genetics* Ku Autoantigen Mitosis / genetics Mutation Nuclear Proteins / chemistry Nuclear Proteins / metabolism* Phosphorylation Protein Kinases / metabolism Schizosaccharomyces / drug effects Schizosaccharomyces / enzymology Schizosaccharomyces / metabolism Schizosaccharomyces pombe Proteins / chemistry Schizosaccharomyces pombe Proteins / genetics Schizosaccharomyces pombe Proteins / metabolism* Topoisomerase I Inhibitors / pharmacology
IF 11.561
Yeast ?