Cytoplasmic localization and ubiquitination of p21(Cip1) by reactive oxygen species

Biochem Biophys Res Commun. 2007 Jun 22;358(1):219-25. doi: 10.1016/j.bbrc.2007.04.120. Epub 2007 Apr 25.


Reactive oxygen species were previously shown to trigger p21(Cip1) protein degradation through a proteasome-dependent pathway, however the detailed mechanism of degradation remains to be elucidated. In this report, we showed that p21(Cip1) was degraded at an early phase after low dose H(2)O(2) treatment of a variety of cell types and that preincubation of cells with the antioxidant, N-acetylcysteine, prolonged p21(Cip1) half-life. A mutant p21(Cip1) in which all six lysines were changed to arginines was protected against H(2)O(2) treatment. Direct interaction between p21(Cip1) and Skp2 was elevated in the H(2)O(2)-treated cells. Disruption of the two nuclear export signal (NES) sequences in p21(Cip1), or treatment with leptomycin B blocked H(2)O(2)-induced p21(Cip1) degradation. Altogether, these results demonstrate that reactive oxygen species induce p21(Cip1) degradation through an NES-, Skp2-, and ubiquitin-dependent pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcysteine / pharmacology
  • Amino Acid Sequence
  • Amino Acid Substitution
  • Animals
  • Antioxidants / pharmacology
  • Cell Line
  • Cyclin-Dependent Kinase Inhibitor p21 / genetics
  • Cyclin-Dependent Kinase Inhibitor p21 / metabolism*
  • Cytoplasm / metabolism*
  • Fatty Acids, Unsaturated / pharmacology
  • Humans
  • Hydrogen Peroxide / pharmacology
  • Molecular Sequence Data
  • Nuclear Export Signals
  • Reactive Oxygen Species / metabolism*
  • S-Phase Kinase-Associated Proteins / metabolism
  • Ubiquitin / metabolism*


  • Antioxidants
  • CDKN1A protein, human
  • Cyclin-Dependent Kinase Inhibitor p21
  • Fatty Acids, Unsaturated
  • Nuclear Export Signals
  • Reactive Oxygen Species
  • S-Phase Kinase-Associated Proteins
  • Ubiquitin
  • Hydrogen Peroxide
  • Acetylcysteine
  • leptomycin B