p53 is phosphorylated in vitro and in vivo by an ultraviolet radiation-induced protein kinase characteristic of the c-Jun kinase, JNK1

Diane M. Milne, Linda E. Campbell, David G. Campbell, David W. Meek

    Research output: Contribution to journalArticlepeer-review

    247 Citations (Scopus)

    Abstract

    The p53 tumor suppressor protein is thought to play a major role in the defense of the cell against agents that damage DNA. In this report, we describe the identification and characterization of a protein kinase that phosphorylates mouse p53 at a single site, serine 34, a major site of phosphorylation in the cell. The protein kinase is activated strikingly following treatment of cells with ultraviolet radiation, has a native molecular weight of approximately 45,000, and can be resolved from mitogen-activated protein (MAP) kinase by chromatography on Superose 6 and DEAE-cellulose. The p53 kinase activity co-purifies with UV-activated c-Jun kinase activity on heparin-Sepharose and on a c-Jun (but not a v-Jun-) affinity column. Treatment of the partially purified kinase with CL100, a protein phosphatase that specifically dephosphorylates MAP kinase homologues, inhibits its activity. Taken together, the data suggest that this p53 kinase is likely to be activated by phosphorylation and may be a member of the stress-activated protein kinase subfamily of MAP kinases. UV irradiation of SV3T3 cells leads to increased phosphorylation of p53 at serine 34, indicating that phosphorylation of p53 by this kinase is likely to be physiological. Phosphorylation of p53 by this protein kinase may be a key event in a signal transduction mechanism that coordinately controls key nuclear proteins in response to oxidative stress or DNA damaging agents.
    Original languageEnglish
    Pages (from-to)5511-5518
    Number of pages8
    JournalJournal of Biological Chemistry
    Volume270
    Issue number10
    DOIs
    Publication statusPublished - 10 Mar 1995

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