Opi1p translocation to the nucleus is regulated by hydrogen peroxide in Saccharomyces cerevisiae

Abstract During exposure of yeast cells to low levels of hydrogen peroxide (H2O2), expression of several genes is regulated for cells to adapt to the surrounding oxidative environment. Such adaptation involves modifying plasma membrane lipid composition, reorganization of ergosterol‐rich microdomains, and altered gene expression of proteins involved in lipid and vesicle traffic, to decrease permeability to exogenous H2O2. Opi1p is a transcriptional repressor that is inactive when present at the nuclear membrane/endoplasmic reticulum, but represses transcription of inositol upstream activating sequence (UASINO)‐containing genes, many of which are involved in the synthesis of phospholipids and fatty acids, when it is translocated to the nucleus. Here, we investigated whether H2O2 in concentrations inducing adaptation regulates Opi1p function. We found that in the presence of H2O2, GFP‐Opi1p fusion protein translocates to the nucleus and, concomitantly, the expression of UASINO‐containing genes is affected. We also investigated whether cysteine residues of Opi1p were implicated in the H2O2‐mediated translocation of this protein to the nucleus and identified cysteine residue 159 as essential for this process. Our work shows that Opi1p is redox‐regulated and establishes a new mechanism of gene regulation involving Opi1p, important for adaptation to H2O2 in yeast cells.
Source: Yeast - Category: Molecular Biology Authors: Tags: Research Article Source Type: research