title: ERKs and p38 kinase phosphorylate p53 protein at serine 15 in response to UV radiation.
abstract: Phosphorylation of the p53 tumor suppressor protein is likely to play an important role in regulating its activity. Serine 15 phosphorylation of p53 leads to a stabilization of p53 by reducing its interaction with murine double minute 2, a negative regulatory partner. Recently, p53 was reported to be activated and phosphorylated at serine 15 following UV radiation. However, the signaling pathway that mediates UV-induced phosphorylation is less well characterized. Here, we provide evidence that UVB-induced phosphorylation of p53 at serine 15 is mediated directly by ERKs and p38 kinase. We find that in a mouse JB6 epidermal cell line, ERKs and p38 kinase form a complex with p53 following UVB radiation. Inhibition of ERKs or p38 kinase activity by the use of a dominant negative mutant of ERK2 or p38 kinase or their respective specific inhibitor, PD98059 or SB202190, results in abrogation of UVB-induced phosphorylation of p53 at serine 15. Strikingly, incubation of UVB-activated ERKs or p38 kinase immunoprecipitated complex with exogenous p53 shows serine 15 phosphorylation of both exogenous and co-precipitated endogenous p53 protein. Additionally, active recombinant ERK1/2 and p38 kinase but not JNKs are also able to phosphorylate p53 at serine 15 in vitro. Furthermore, pretreatment of cells with PD98059 or SB202190 blocks p53-dependent transcription activity but increases the level of p53 co-precipitated murine double minute. These results strongly suggest that both ERKs and p38 kinase have a direct role in UVB-induced phosphorylation of p53 at serine 15 in vivo.
authors.affiliation: Hormel Institute, University of Minnesota, Austin, Minnesota 55912, USA.
authors.forename: Q B
authors.initials: QB
authors.lastname: She
authors.forename: N
authors.initials: N
authors.lastname: Chen
authors.forename: Z
authors.initials: Z
authors.lastname: Dong
mesh_terms: D000818:Animals; D002460:Cell Line; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010766:Phosphorylation / Q000528:radiation effects; D011725:Pyridines / Q000494:pharmacology; D012694:Serine / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D014466:Ultraviolet Rays; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D011725:Pyridines; D016159:Tumor Suppressor Protein p53; D012694:Serine; D019950:Mitogen-Activated Protein Kinase 1; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one