Delayed cell cycle progression in selenoprotein w-depleted cells is regulated by a mitogen-activated protein kinase kinase 4-p38/c-Jun NH 2-terminal kinase-p53 pathway

Wayne Chris Hawkes, Zeynep Alkan

Research output: Contribution to journalArticle

24 Scopus citations


Selenoprotein W (SEPW1) is a ubiquitous, highly conserved thioredoxin-like protein whose depletion causes a transient p53- and p21 Cip1-dependent G 1-phase cell cycle arrest in breast and prostate epithelial cells. SEPW1 depletion increases phosphorylation of Ser-33 in p53, which is associated with decreased p53 ubiquitination and stabilization of p53. We report here that delayed cell cycle progression, Ser-33 phosphorylation, and p53 nuclear accumulation from SEPW1 depletion require mitogen-activated protein kinase kinase 4 (MKK4). Silencing MKK4 rescued G 1 arrest, Ser-33 phosphorylation, and nuclear accumulation of p53 induced by SEPW1 depletion, but silencing MKK3, MKK6, or MKK7 did not. SEPW1 silencing did not change the phosphorylation state of MKK4 but increased total MKK4 protein. Silencing p38γ, p38δ, or JNK2 partially rescued G 1 arrest from SEPW1 silencing, suggesting they signal downstream from MKK4. These results imply that SEPW1 silencing increases MKK4, which activates p38γ, p38δ, and JNK2 to phosphorylate p53 on Ser-33 and cause a transient G 1 arrest.

Original languageEnglish (US)
Pages (from-to)27371-27379
Number of pages9
JournalJournal of Biological Chemistry
Issue number33
StatePublished - Aug 10 2012


ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

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