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Stationary‐phase induction of GLR1 expression is mediated by the yAP‐1 transcriptional regulatory protein in the yeast Saccharomyces cerevisiae
Author(s) -
Grant Chris M.,
MacIver Fiona H.,
Dawes Ian W.
Publication year - 1996
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1996.d01-1727.x
Subject(s) - glutathione , biology , saccharomyces cerevisiae , biochemistry , glutathione reductase , yeast , reductase , exponential growth , stationary phase , transcriptional regulation , microbiology and biotechnology , gene expression , enzyme , gene , chemistry , chromatography , mathematical analysis , mathematics , glutathione peroxidase
Glutathione (GSH) is an abundant low‐molecular‐mass thiol which has been implicated in numerous cellular processes including protection against cytotoxic agents such as xenobiotics, carcinogens and free radicals. Utilization of GSH results in its conversion to the oxidized form (GSSG), and it is recycled to GSH by the action of glutathione reductase (GLR) using the reducing power of NADPH. We show that GLR activity is increased by three‐ to fourfold during stationary‐phase growth compared to exponential phase growth, and that a yeast strain deleted for GLR1 , encoding glutathione reductase, shows an elevated sensitivity to H 2 O 2 challenge during stationary phase. These data indicate an increased requirement for GSH as the cell arrests growth and enters stationary phase. The stationary‐phase increase in GLR activity is entirely dependent upon the action of the yAP‐1 transcriptional regulatory protein, previously implicated in regulating GLR activity in response to oxidative stress. Thus, both oxidant‐ and growth phase‐mediated control of GLR1 expression are regulated by the same transcriptional control mechanism. In addition, strains lacking GLR or yAP‐1 do not accumulate GSSG during stationary‐phase growth, indicating that the cell possesses alternative means of preventing an accumulation of GSSG during stationary phase.