title: Regulation of mitochondrial thioredoxin peroxidase I expression by two different pathways: one dependent on cAMP and the other on heme.
abstract: Mitochondrial isoform of thioredoxin peroxidase (mTPx I) is an antioxidant protein recently described in Saccharomyces cerevisiae. Here we characterized pathways that lead to mTPx I induction in two situations: growth in media containing low glucose concentrations and treatment with peroxides. The induction of mTPx I by growth on low glucose concentrations was dependent on cAMP and on the transcription factors Msn2p/Msn4p as demonstrated by northern blot experiments using yeast strains with deletion of MSN2 and MSN4 genes and also using a strain permeable to cAMP. mTPx I expression was also induced by peroxides in a time- and dose-dependent manner and varied with the carbon source present in the media. Deletion of HAP1 or inhibition of heme synthesis abolished induction of mTPx I by H(2)O(2) on cells which were grown in media containing glucose, indicating that Hap1p is involved in the regulation of this process. mTPx I was induced by H(2)O(2) on glycerol/ethanol-containing media, but we could not associate any transcription factor with this phenomenon. Finally, mTPx I also induced by t-butyl hydroperoxide in a Hap1p-independent manner. In conclusion, mTPx I expression is under a complex regulatory network, which involves, at least, two signaling pathways: one sensing the carbon source (which is signalized by cAMP) and the other sensing the intracellular redox state (which is signalized by heme).
authors.affiliation: Departamento de Genética e Evolução, Instituto de Biologia, UNICAMP, Campinas, São Paulo, Brazil.
authors.forename: Gisele
authors.initials: G
authors.lastname: Monteiro
authors.forename: Gonçalo Amarante Guimarães
authors.initials: GA
authors.lastname: Pereira
authors.forename: Luis Eduardo Soares
authors.initials: LE
authors.lastname: Netto
mesh_terms: D000242:Cyclic AMP / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology; D006418:Heme / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000201:enzymology*; D009363:Neoplasm Proteins; D018384:Oxidative Stress; D010544:Peroxidases / Q000235:genetics / Q000378:metabolism*; D010545:Peroxides / Q000494:pharmacology; D054464:Peroxiredoxins; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D007527:Isoenzymes; C081935:MSN2 protein, S cerevisiae; C081937:MSN4 protein, S cerevisiae; D009363:Neoplasm Proteins; D010545:Peroxides; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D006418:Heme; D000242:Cyclic AMP; D010544:Peroxidases; D054464:Peroxiredoxins; D005947:Glucose