Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/102798
Type: Artigo de periódico
Title: Yeast Oxidative Stress Response: Influences Of Cytosolic Thioredoxin Peroxidase I And Of The Mitochondrial Functional State
Author: Demasi A.P.D.
Pereira G.A.G.
Netto L.E.S.
Abstract: We investigated the changes in the oxidative stress response of yeast cells suffering mitochondrial dysfunction that could impair their viability. First, we demonstrated that cells with this dysfunction rely exclusively on cytosolic thioredoxin peroxidase I (cTPxI) and its reductant sulfiredoxin, among other antioxidant enzymes tested, to protect them against H2O 2-induced death. This cTPxI-dependent protection could be related to its dual functions, as peroxidase and as molecular chaperone, suggested by mixtures of low and high molecular weight oligomeric structures of cTPxI observed in cells challenged with H2O2. We found that cTPxI deficiency leads to increased basal sulfhydryl levels and transcriptional activation of most of the H2O2-responsive genes, interpreted as an attempt by the cells to improve their antioxidant defense. On the other hand, mitochondrial dysfunction, specifically the electron transport blockage, provoked a huge depletion of sulfhydryl groups after H 2O2 treatment and reduced the H2O 2-mediated activation of some genes otherwise observed, impairing cell defense and viability. The transcription factors Yap1 and Skn7 are crucial for the antioxidant response of cells under inhibited electron flow condition and probably act in the same pathway of cTPxI to protect cells affected by this disorder. Yap1 cellular distribution was not affected by cTpxI deficiency and by mitochondrial dysfunction, in spite of the observed expression alterations of several Yap1-target genes, indicating alternative mechanisms of Yap1 activation/deactivation. Therefore, we propose that cTPxI is specifically important in the protection of yeast with mitochondrial dysfunction due to its functional versatility as an antioxidant, chaperone and modulator of gene expression. © 2006 FEBS.
Editor: 
Rights: fechado
Identifier DOI: 10.1111/j.1742-4658.2006.05116.x
Address: http://www.scopus.com/inward/record.url?eid=2-s2.0-33644932478&partnerID=40&md5=8f531e8ee25346241f3fbb0f5dc0ec00
Date Issue: 2006
Appears in Collections:Unicamp - Artigos e Outros Documentos

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