The ataxia-telangiectasia related protein ATR mediates DNA-dependent phosphorylation of p53

• Published in: Oncogene Vol. 18; no. 27; pp. 3989 - 3995
• Main Authors: LAKIN, N. D, HANN, B. C, JACKSON, S. P
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing 08.07.1999; Nature Publishing Group
• Subjects: Ataxia; Ataxia Telangiectasia - enzymology; Ataxia Telangiectasia - metabolism; Ataxia Telangiectasia Mutated Proteins; Biological and medical sciences; Catalysis; Cell cycle; Cell Cycle Proteins - physiology; Cell physiology; Cell transformation and carcinogenesis. Action of oncogenes and antioncogenes; Deoxyribonucleic acid; DNA; DNA - physiology; DNA damage; DNA-Activated Protein Kinase; DNA-Binding Proteins; DNA-dependent protein kinase; Fundamental and applied biological sciences. Psychology; HeLa Cells; Humans; Immunoprecipitation; Kinases; MDM2 protein; Molecular and cellular biology; Nuclear Proteins; p21-Activated Kinases; p53 Protein; Phosphatidylinositol 3-Kinases - metabolism; Phosphorylation; Polypeptides; Protein-Serine-Threonine Kinases - metabolism; Proteins; Proteins - physiology; Serine; Serine - metabolism; Signal transduction; Tumor suppressor genes; Tumor Suppressor Protein p53 - metabolism; Tumor Suppressor Proteins; Tumors; Ubiquitin; Human; Immunopathology; Skin disease; Nervous system diseases; Phosphorylation; Enzyme; Transferases; p53 Protein; Cardiovascular disease; Genetic disease; Vascular disease; Signal transduction; Eye disease; Protein kinase; DNA; Ataxia telangiectasia; Lesion; Tumor suppressor gene
• ISSN: 0950-9232; 1476-5594
• DOI: 10.1038/sj.onc.1202973

Levels of the tumour suppressor protein p53 are increased in response to a variety of DNA damaging agents. DNA damage-induced phosphorylation of p53 occurs at serine-15 in vivo. Phosphorylation of p53 at serine-15 leads to a stabilization of the polypeptide by inhibiting its interaction with Mdm2, a protein that targets p53 for ubiquitin-dependent degradation. However, the mechanisms by which DNA damage is signalled to p53 remain unclear. Here, we report the identification of a novel DNA-activated protein kinase that phosphorylates p53 on serine-15. Fractionation of HeLa nuclear extracts and biochemical analyses indicate that this kinase is distinct from the DNA-dependent protein kinase (DNA-PK) and corresponds to the human cell cycle checkpoint protein ATR. Immunoprecipitation studies of recombinant ATR reveal that catalytic activity of this polypeptide is required for DNA-stimulated phosphorylation of p53 on serine-15. These data suggest that ATR may function upstream of p53 in a signal transduction cascade initiated upon DNA damage and provide a biochemical assay system for ATR activity.