DNA damage-induced phosphorylation of MdmX at serine 367 activates p53 by targeting MdmX for Mdm2-dependent degradation

Koji Okamoto, Kenji Kashima, Yaron Pereg, Michiko Ishida, Satomi Yamazaki, Ayumi Nota, Amina Teunisse, Domenico Migliorini, Issay Kitabayashi, Jean Christophe Marine, Carol Prives, Yosef Shiloh, Aart G. Jochemsen, Yoichi Taya

研究成果: ジャーナルへの寄稿学術論文査読

109 被引用数 (Scopus)

抄録

Understanding how p53 activity is regulated is crucial in elucidating mechanisms of cellular defense against cancer. Genetic data indicate that Mdmx as well as Mdm2 plays a major role in maintaining p53 activity at low levels in nonstressed cells. However, biochemical mechanisms of how Mdmx regulates p53 activity are not well understood. Through identification of Mdmx-binding proteins, we found that 14-3-3 proteins are associated with Mdmx. Mdmx harbors a consensus sequence for binding of 14-3-3. Serine 367 (S367) is located within the putative binding sequence for 14-3-3, and its substitution with alanine (S367A) abolishes binding of Mdmx to 14-3-3. Transfection assays indicated that the S367A mutation, in cooperation with Mdm2, enhances the ability of Mdmx to repress the transcriptional activity of p53. The S367A mutant is more resistant to Mdm2-dependent ubiquitination and degradation than wild-type Mdmx, and Mdmx phosphorylated at S367 is preferentially degraded by Mdm2. Several types of DNA damage markedly enhance S367 phosphorylation, coinciding with increased binding of Mdmx to 14-3-3 and accelerated Mdmx degradation. Furthermore, promotion of growth of normal human fibroblasts after introduction of Mdmx is enhanced by the S367 mutation. We propose that Mdmx phosphorylation at S367 plays an important role in p53 activation after DNA damage by triggering Mdm2-dependent degradation of Mdmx.

本文言語英語
ページ(範囲)9608-9620
ページ数13
ジャーナルMolecular and Cellular Biology
25
21
DOI
出版ステータス出版済み - 11-2005
外部発表はい

All Science Journal Classification (ASJC) codes

  • 分子生物学
  • 細胞生物学

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