Regulation of mitochondrial thioredoxin peroxidase I expression by two different pathways: one dependent on cAMP and the other on heme.
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).
Monteiro
Gisele
G
Departamento de Genética e Evolução, Instituto de Biologia, UNICAMP, Campinas, São Paulo, Brazil.
Pereira
Gonçalo Amarante Guimarães
GA
Netto
Luis Eduardo Soares
LE
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
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