HYR1 encodes a thiol peroxidase involved in the cellular response to oxidative stress (5). Originally identified along with GRX1 and GRX2 as glutathione peroxidase homologs (2), later studies showed that these three proteins were more similar in sequence, structure, and function to phospholipid hydroperoxide glutathione peroxidases (PHGPxs) (5, 6). Hyr1p is able to act on glutathione, phospholipid hydroperoxides, and thioredoxin as substrates (2, 5, 3). In addition to protecting cells directly from peroxides during oxidative stress, Hyr1p also regulates and acts as a hyroperoxide sensor for the oxidative stress transcription factor Yap1p (6, 3, 7). In response to peroxide stress, Hyr1p forms a disulfide bond in the C-terminus of Yap1p, which inhibits Yap1p nuclear export resulting in activated Yap1p-dependent transcription (3). The Hyr1p-dependent activation of Yap1p is also dependent on the protein Ybp1p (8). Null mutants of hyr1 are sensitive to peroxides and aluminum (2, 9). PHGPxs are a conserved family of proteins and are found in organisms such as plant, rat, and human (5).

Last updated: 2011-01-10