Regulation of the inositol transporter Itr1p by hydrogen peroxide in Saccharomyces cerevisiae
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Myo-inositol is a precursor of several membrane phospholipids and sphingolipids and plays a key role in gene regulation in Saccharomyces cerevisiae (S. cerevisiae). Here, we tested whether H2O2 was affecting the levels of the inositol transporters and thus inositol uptake. In S. cerevisiae cells adapted to H2O2 Itr1–GFPp accumulated in the plasma membrane until 20 min, concomitantly with an inhibition of its internalization. Exposure to H2O2 did not alter Itr2–GFPp cellular levels and induced only an 8% decrease at 10 min in the plasma membrane. Therefore, decreased inositol intracellular levels are not caused by decreased levels of inositol transporters in the plasma membrane. However, results show that H2O2 adaptation affects Itr1p turnover and, consequently, H2O2-adapted yeast cells display an inositol transporter phenotype comparable to cells grown in the absence of inositol in growth medium, i.e. accumulation in the plasma membrane and decreased degradation.
KeywordsRedox signaling Hydrogen peroxide Saccharomyces cerevisiae Myo-inositol transporters Inositol Adaptation
One-way analysis of variance
Arrestin-related trafficking adaptors
Fusion between green fluorescence protein and Opi1 protein
Inositol-1-phosphate synthase gene
Myo-inositol transporter 1 gene
Fusion between Itr1 protein and green fluorescence protein
Myo-inositol transporter 2 gene
Fusion between Itr2 protein and green fluorescence protein
Inositol upstream activating sequence
E3 ubiquitin ligase that conjugates ubiquitin to proteins to target them for degradation
Synthetic complete medium
We thank Dr. André Bastos for help in the endocytosis assays, Dr. Filipe Vilas-Boas for helpful discussions and critical reading of the manuscript and Dr. Helena Soares for help in the preparation of the figures. This work was supported by Fundação para a Ciência e a Tecnologia (FCT), Grant PEst-OE/QUI/UI0612/2013.
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Conflict of interest
The authors declare that there is no conflict of interest.
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