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Regulation of the inositol transporter Itr1p by hydrogen peroxide in Saccharomyces cerevisiae

Santos, Tomás, Marinho, H. Susana, Cyrne, Luisa
Archives of microbiology 2019 v.201 no.1 pp. 123-134
Saccharomyces cerevisiae, culture media, genes, hydrogen peroxide, myo-inositol, phenotype, phospholipids, plasma membrane, sphingolipids, transporters, yeasts
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.