title: Regulatory interactions between the checkpoint kinase Chk1 and the proteins of the DNA-dependent protein kinase complex.
abstract: Checkpoints are biochemical pathways that provide cells a mechanism to detect DNA damage and respond by arresting the cell cycle to allow DNA repair. The conserved checkpoint kinase, Chk1, regulates mitotic progression in response to DNA damage by blocking the activation of Cdk1/cyclin B. In this study, we investigate the regulatory interaction between Chk1 and members of the Atm family of kinases and the functional role of the C-terminal non-catalytic domains of Chk1. Chk1 stimulates the kinase activity of DNA-PK (protein kinase) complexes, which leads to increased phosphorylation of p53 on Ser-15 and Ser-37. In addition, Chk1 stimulates DNA-PK-dependent end-joining reactions in vitro. We also show that Chk1 protein complexes bind to single-stranded DNA and DNA ends. These results indicate a connection between components that regulate the checkpoint pathways and DNA-PK complex proteins, which have a role in the repair of double strand breaks.
authors.affiliation: Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0524, USA.
authors.forename: Dawn Marie
authors.initials: DM
authors.lastname: Goudelock
authors.forename: Kecheng
authors.initials: K
authors.lastname: Jiang
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Pereira
authors.forename: Beatriz
authors.initials: B
authors.lastname: Russell
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Sanchez
mesh_terms: D034961:Antigens, Nuclear / Q000737:chemistry; D015153:Blotting, Western; D002384:Catalysis; D020134:Catalytic Domain; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D000071877:Checkpoint Kinase 1; D003001:Cloning, Molecular; D019926:Cyclin B / Q000378:metabolism; D004249:DNA Damage; D004265:DNA Helicases; D004260:DNA Repair; D004277:DNA, Single-Stranded; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins / Q000737:chemistry; D005982:Glutathione Transferase / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D000072200:Ku Autoantigen; D008856:Microscopy, Fluorescence; D008938:Mitosis; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D011494:Protein Kinases / Q000737:chemistry* / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012694:Serine / Q000737:chemistry; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D034961:Antigens, Nuclear; D019926:Cyclin B; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D016159:Tumor Suppressor Protein p53; D012694:Serine; D005982:Glutathione Transferase; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; D051747:DNA-Activated Protein Kinase; C497263:PRKDC protein, human; D017346:Protein Serine-Threonine Kinases; D004265:DNA Helicases; C106893:XRCC5 protein, human; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen