title: Thioredoxin-dependent redox regulation of p53-mediated p21 activation.
abstract: Thioredoxin (TRX) is a dithiol-reducing enzyme that is induced by various oxidative stresses. TRX regulates the activity of DNA-binding proteins, including Jun/Fos and nuclear factor-kappaB. TRX also interacts with an intranuclear reducing molecule redox factor 1 (Ref-1), which enhances the activity of Jun/Fos. Here, we have investigated the role of TRX in the regulation of p53 activity. Electrophoretic mobility shift assay showed that TRX augmented the DNA binding activity of p53 and also further potentiated Ref-1-enhanced p53 activity. Luciferase assay revealed that transfection of TRX enhanced p53-dependent expression of p21 and further intensified Ref-1-mediated p53 activation. Furthermore, Western blot analysis revealed that p53-dependent induction of p21 protein was also facilitated by transfection with TRX. Overexpression of transdominant negative mutant TRX (mTRX) suppressed the effects of TRX or Ref-1, showing a functional interaction between TRX and Ref-1. cis-Diamminedichloroplatinum (II) (CDDP) induced p53 activation and p21 transactivation. The p53-dependent p21 transactivation induced by CDDP was inhibited by mTRX overexpression, suggesting that TRX-dependent redox regulation is physiologically involved in p53 regulation. CDDP also stimulated translocation of TRX from the cytosol into the nucleus. Hence, TRX-dependent redox regulation of p53 activity indicates coupling of the oxidative stress response and p53-dependent repair mechanism.
authors.affiliation: Department of Biological Responses, Institute for Virus Research, 53 Kawahara-cho, Shogoin, Kyoto University, Kyoto 606-8507
authors.forename: M
authors.initials: M
authors.lastname: Ueno
authors.forename: H
authors.initials: H
authors.lastname: Masutani
authors.forename: R J
authors.initials: RJ
authors.lastname: Arai
authors.forename: A
authors.initials: A
authors.lastname: Yamauchi
authors.forename: K
authors.initials: K
authors.lastname: Hirota
authors.forename: T
authors.initials: T
authors.lastname: Sakai
authors.forename: T
authors.initials: T
authors.lastname: Inamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Yamaoka
authors.forename: J
authors.initials: J
authors.lastname: Yodoi
authors.forename: T
authors.initials: T
authors.lastname: Nikaido
mesh_terms: D019757:Carbon-Oxygen Lyases / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002945:Cisplatin / Q000494:pharmacology; D003110:Colonic Neoplasms; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000235:genetics* / Q000378:metabolism*; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004260:DNA Repair; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D003958:Diamide / Q000494:pharmacology; D004229:Dithiothreitol / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D008156:Luciferases / Q000235:genetics; D010084:Oxidation-Reduction; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D013879:Thioredoxins / Q000494:pharmacology*; D015533:Transcriptional Activation / Q000187:drug effects; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004791:Enzyme Inhibitors; D011994:Recombinant Proteins; D016159:Tumor Suppressor Protein p53; D003958:Diamide; D013879:Thioredoxins; D008156:Luciferases; D019757:Carbon-Oxygen Lyases; C085108:APEX1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D002945:Cisplatin; D004229:Dithiothreitol