Abstract
In response to DNA damage, cells activate checkpoint pathways that prevent cell cycle progression. In fission yeast and mammals, mitotic arrest in response to DNA damage requires inhibitory Cdk phosphorylation regulated by Chk1. This study indicates that Chk1 is required for function of the DNA damage checkpoint in Saccharomyces cerevisiae but acts through a distinct mechanism maintaining the abundance of Pds1, an anaphase inhibitor. Unlike other checkpoint mutants, chk1 mutants were only mildly sensitive to DNA damage, indicating that checkpoint functions besides cell cycle arrest influence damage sensitivity. Another kinase, Rad53, was required to both maintain active cyclin-dependent kinase 1, Cdk1(Cdc28), and prevent anaphase entry after checkpoint activation. Evidence suggests that Rad53 exerts its role in checkpoint control through regulation of the Polo kinase Cdc5. These results support a model in which Chk1 and Rad53 function in parallel through Pds1 and Cdc5, respectively, to prevent anaphase entry and mitotic exit after DNA damage. This model provides a possible explanation for the role of Cdc5 in DNA damage checkpoint adaptation.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Anaphase
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Anaphase-Promoting Complex-Cyclosome
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CDC2 Protein Kinase / metabolism
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism
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Checkpoint Kinase 1
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Checkpoint Kinase 2
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Cyclin B / genetics
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Cyclin B / metabolism
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DNA Damage*
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DNA, Fungal / metabolism
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Fungal Proteins / genetics
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Fungal Proteins / metabolism
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Intracellular Signaling Peptides and Proteins
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Ligases / metabolism
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Mitosis*
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Mutation
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Nuclear Proteins / metabolism
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Phosphorylation
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Protein Kinases / genetics
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Protein Kinases / metabolism*
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Protein Serine-Threonine Kinases*
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RNA-Binding Proteins
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Recombinant Fusion Proteins / metabolism
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S Phase
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Saccharomyces cerevisiae / cytology*
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Saccharomyces cerevisiae / enzymology*
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae Proteins*
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Securin
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Ubiquitin-Protein Ligase Complexes*
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Ubiquitin-Protein Ligases
Substances
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CEF1 protein, S cerevisiae
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Cell Cycle Proteins
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Cyclin B
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DNA, Fungal
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Fungal Proteins
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Intracellular Signaling Peptides and Proteins
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Nuclear Proteins
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PDS1 protein, S cerevisiae
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RNA-Binding Proteins
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Recombinant Fusion Proteins
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Saccharomyces cerevisiae Proteins
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Securin
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rad9 protein
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Ubiquitin-Protein Ligase Complexes
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Anaphase-Promoting Complex-Cyclosome
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Ubiquitin-Protein Ligases
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Protein Kinases
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Checkpoint Kinase 2
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Checkpoint Kinase 1
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MEC1 protein, S cerevisiae
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Protein Serine-Threonine Kinases
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CDC2 Protein Kinase
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RAD53 protein, S cerevisiae
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Ligases