Roles of thioredoxin reductase 1 and APE/Ref-1 in the control of basal p53 stability and activity

Oncogene. 2005 Jun 2;24(24):3853-63. doi: 10.1038/sj.onc.1208549.


The p53 protein is redox-sensitive in vitro but in vivo effectors of this sensitivity are not known. In yeasts deficient for thioredoxin (Trx) reductase (TRR), p53 accumulates in an inactive, oxidized form, suggesting a role for TRR-Trx in controlling p53. In mammalian cells, p53 binds to redox factor-1 (APE/Ref-1), an enzyme containing an abasic endonuclease domain involved in base excision repair, and a thiol reductase domain recycled by Trx and involved in regulating the transcription factor AP-1. To evaluate the role of TRR and APE/Ref-1 in p53 regulation, we have abrogated their expression using RNA interference in cell lines expressing wild-type p53. Inhibition of TRR resulted in accumulation of oxidized Trx and increased levels and DNA-binding activity of p53, with no phosphorylation of Ser15 or Ser20. In contrast, inhibition of APE/Ref-1 accelerated p53 protein turnover, resulting in a decrease in p53 levels and activity. However, inhibition of either TRR or APE/Ref-1 did not prevent activation and accumulation of p53 in response to DNA-damage by doxorubicin. When both factors were inhibited, basal levels of p53 were restored. These results suggest that TRR-Trx and APE/Ref-1 cooperate in the control of basal p53 activity, but not in its induction by DNA-damage.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Breast Neoplasms
  • Cell Line, Tumor
  • DNA Damage
  • DNA Primers
  • DNA-(Apurinic or Apyrimidinic Site) Lyase / metabolism*
  • Female
  • Gene Expression Regulation, Neoplastic
  • Genes, p53
  • Humans
  • Phosphorylation
  • Reverse Transcriptase Polymerase Chain Reaction
  • Thioredoxin Reductase 1
  • Thioredoxin-Disulfide Reductase / metabolism*
  • Transcription Factor AP-1 / metabolism
  • Tumor Suppressor Protein p53 / metabolism*


  • DNA Primers
  • Transcription Factor AP-1
  • Tumor Suppressor Protein p53
  • TXNRD1 protein, human
  • Thioredoxin Reductase 1
  • Thioredoxin-Disulfide Reductase
  • APEX1 protein, human
  • DNA-(Apurinic or Apyrimidinic Site) Lyase