rad-Dependent Response of the chk1-Encoded Protein Kinase at the DNA Damage Checkpoint

• Published in: Science (American Association for the Advancement of Science) 1996-01, Vol.271 (5247), p.353-356
• Main Authors: Walworth, Nancy C., Bernards, Rene
• Format: Article
• Language: English
• Subjects: Adenosine Triphosphatases - genetics; Alleles; Ataxia Telangiectasia Mutated Proteins; Base Sequence; Biological and medical sciences; Cell cycle; Cell Cycle Proteins; Cellular biology; Checkpoint Kinase 1; Complementary DNA; Deoxyribonucleic acid; DNA; DNA Damage; DNA Helicases - genetics; DNA Replication; DNA, Fungal - metabolism; DNA, Fungal - radiation effects; DNA-Binding Proteins; Electrophoresis, Polyacrylamide Gel; Epitopes; Fundamental and applied biological sciences. Psychology; G2 Phase; Gamma rays; Genes, Fungal; Humans; Light; Mitosis; Mobility; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Mutagenesis. Repair; Mutation; Observation; Phosphorylation; Physiological aspects; Protein Kinases - chemistry; Protein Kinases - genetics; Protein Kinases - metabolism; Protein-Serine-Threonine Kinases; Proteins; Proteins - genetics; Radiation; Radiation damage; Radiation dosage; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - metabolism; Saccharomyces cerevisiae Proteins; Schizosaccharomyces - cytology; Schizosaccharomyces - genetics; Schizosaccharomyces - radiation effects; Schizosaccharomyces pombe; Schizosaccharomyces pombe Proteins; Tumor Suppressor Proteins; Ultraviolet Rays
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.271.5247.353

Exposure of eukaryotic cells to agents that generate DNA damage results in transient arrest of progression through the cell cycle. In fission yeast, the DNA damage checkpoint associated with cell cycle arrest before mitosis requires the protein kinase p56$^{chk1}$. DNA damage induced by ultraviolet light, gamma radiation, or a DNA-alkylating agent has now been shown to result in phosphorylation of p56$^{chk1}$. This phosphorylation decreased the mobility of p56$^{chk1}$ on SDS-polyacrylamide gel electrophoresis and was abolished by a mutation in the p56$^{chk1}$ catalytic domain, suggesting that it might represent autophosphorylation. Phosphorylation of p56$^{chk1}$ did not occur when other checkpoint genes were inactive. Thus, p56$^{chk1}$ appears to function downstream of several of the known Schizosaccharomyces pombe checkpoint gene products, including that encoded by rad3$^+$, a gene with sequence similarity to the ATM gene mutated in patients with ataxia telangiectasia. The phosphorylation of p56$^{chk1}$ provides an assayable biochemical response to activation of the DNA damage checkpoint in the G$_2$ phase of the cell cycle.