Requirement of ATM for rapid p53 phosphorylation at Ser46 without Ser/Thr-Gln sequences.
p53 phosphorylation at Ser46 following DNA damage is important for preferential transactivation of proapoptotic genes. Here, we report that ataxia-telangiectasia mutated (ATM) kinase is responsible for Ser46 phosphorylation of p53 during early-phase response to DNA damage. To elucidate the direct phosphorylation of p53 at Ser46 by ATM, an ATM mutant ... (ATM-AS) sensitive to ATP analogues was engineered. In vitro kinase assays revealed that p53 was phosphorylated at Ser46 by ATM-AS, even when ATP analogues were used as phosphate donors, although this phosphorylation site is not in an SQ motif, a consensus ATM site. Furthermore, Ser46 phosphorylation by ATM was dependent on the N- and C-terminal domains of p53, unlike Ser15 phosphorylation. Immunofluorescence analyses showed that Ser46-phosphorylated p53 was observed as foci in response to DNA damage and colocalized with gamma-H2AX or Ser1981-phosphorylated ATM. These results suggest that ATM phosphorylates a noncanonical serine residue on p53 by mechanisms different from those for the phosphorylation of Ser15.
Mesh Terms:
Adenosine Triphosphate, Animals, Ataxia Telangiectasia Mutated Proteins, Base Sequence, Cell Cycle Proteins, Cell Line, DNA, DNA Damage, DNA-Binding Proteins, Glutamine, Humans, Molecular Structure, Phosphorylation, Protein Serine-Threonine Kinases, RNA Interference, Recombinant Fusion Proteins, Serine, Threonine, Tumor Suppressor Protein p53, Tumor Suppressor Proteins
Adenosine Triphosphate, Animals, Ataxia Telangiectasia Mutated Proteins, Base Sequence, Cell Cycle Proteins, Cell Line, DNA, DNA Damage, DNA-Binding Proteins, Glutamine, Humans, Molecular Structure, Phosphorylation, Protein Serine-Threonine Kinases, RNA Interference, Recombinant Fusion Proteins, Serine, Threonine, Tumor Suppressor Protein p53, Tumor Suppressor Proteins
Mol Cell Biol
Date: Apr. 01, 2010
PubMed ID: 20123963
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