Cooperation of Yeast Peroxiredoxins Tsa1p and Tsa2p in the Cellular Defense against Oxidative and Nitrosative Stress

Abstract

Peroxiredoxins are a family of antioxidant enzymes conserved from bacteria to humans. In Saccharomyces cerevisiae, there exist five peroxiredoxins, among which Tsa2p shares striking homology with the well described Tsa1p but has not been extensively studied. Here we report on the functional characterization of yeast tsa2⌬ mutants and the comparison of TSA1 with TSA2. The tsa2⌬ and tsa1⌬ tsa2⌬ cells grew normally under aerobic conditions. However, the tsa1⌬ tsa2⌬ mutant yeast was more susceptible to oxidants than either tsa1⌬ or tsa2⌬ cells. Notably, the tsa1⌬ tsa2⌬ yeast was also hypersensitive to peroxynitrite and sodium nitroprusside. This phenotype was rescued by the expression of either the TSA1 or TSA2 gene. The demonstration of a peroxynitrite reductase activity of Tsa2p in vitro points to a pivotal role for peroxiredoxins in the protection against nitrosative stress. In yeast cells, Tsa1p and Tsa2p exhibited comparable antioxidant activity. While the basal expression level of TSA1 was significantly higher than that of TSA2, the transcription of TSA2 was stimulated more potently by various oxidants. In addition, TSA2 was activated in tsa1⌬ cells in a Yap1p-dependent manner. Taken together, our findings implicate the cooperation of Tsa1p and Tsa2p in the cellular defense against reactive oxygen and nitrogen species.Living organisms are constantly exposed to reactive oxygen species (ROS) 1 that are produced during metabolism or in response to external stimuli (1). In addition to ROS, reactive nitrogen species (RNS) have emerged as another source of oxidative and nitrosative stress (2, 3). Both ROS and RNS have been implicated in various physiological and pathological processes including metabolism, immunity, inflammation, cell signaling, transcriptional regulation, and apoptosis (1-3). The cellular defense against oxidative and nitrosative stress is important for homeostasis and survival.Antioxidant enzymes are important components of the cellular defense system against ROS and RNS. In addition to well documented antioxidant enzymes such as superoxide dismutase and catalase, a novel family of peroxidases, designated peroxiredoxins, has recently been characterized (4 -6). Peroxiredoxins are found in all organisms ranging from bacteria to humans. They are thought to be active peroxidases supported by thioredoxin and other electron donors (5, 7). The amino acid sequences around the peroxidatic center characterized by a cysteine residue are highly conserved. The oxidation of the cysteine induced the formation of a decameric structure comprising five dimers (8, 9). In a more recent study, bacterial peroxiredoxin AhpC has been shown to be peroxynitrite reductase (10), thus conferring resistance to RNS (11). It remains to be seen whether eukaryotic peroxiredoxins can generally scavenge peroxynitrite in addition to hydrogen peroxide and directly protect cells from RNS.Multiple subtypes of peroxiredoxins are often found in one species (6). Thus, there are five peroxiredoxin genes (TSA1/ cTPxI/YML026W, TSA2/cTPxII/Y...

A mosquito 2-Cys peroxiredoxin protects against nitrosative and oxidative stresses associated with malaria parasite infection

“…Finally, the pool of heterodimeric (fruitfly and mosquito) Prx-4783 in transfected cells may be less efficient at peroxide reduction than homodimeric DmPrx-4783. Heterodimer formation and cooperativity between heterologous monomers of 2-Cys Prxs have been observed and provide additional regulation of activity [4,56,57]. However, it is possible that the interspecies heterodimer is less efficient than either homodimer in protecting S2 cells from damage due to treatment with hydrogen peroxide and (Fig.…”

“…In organisms ranging from yeast to insects to human cells, Prx gene silencing has resulted in decreased cell survival when deficient cells are exposed to toxic oxidative and nitrosative stress [4,14,35]. Therefore, to provide additional supporting data that AsPrx-4783 protected A. stephensi cells against ROS-and RNOS-associated damage, we used dsRNA-mediated RNA interference to silence AsPrx-4783 expression in A. stephensi cells.…”

“…In contrast, gene products that confer protection against RNOS have been identified, but are less well studied. The peroxiredoxins (Prxs) are a recently discovered family of antioxidant peroxidases that can reduce hydrogen peroxide and alkyl hydroperoxides to water and the corresponding alcohols, respectively, and can protect cells from widely divergent organisms against a variety of nitrosative stress challenges [2][3][4][5][6].…”

Mutator genes for suppression of gross chromosomal rearrangements identified by a genome-wide screening in Saccharomyces cerevisiae

“…The higher sensitivity of the alo1⌬ mutant to oxidative stress suggests that ALO1 also functions in the oxidative stress response (36). Interestingly, TSA1, another GCR mutator gene identified in this study, encodes a protein functioning in oxidative response to protect cells from free-radical damage (37). Mutations of ALO1 and TSA1 genes increased the GCR rate 134-and 7-fold compared with wild type, respectively (Table 2).…”

Differential tissue-specific protein markers of vaginal carcinoma

“…There are five peroxiredoxins (Prx) genes. TSA 1p was the first peroxiredoxin to be identified and has been shown to be the major thioredoxin peroxidase in cytoplasm (Wong et al, 2002). The members of the peroxiredoxin family have diverse functions associated with various biological processes including detoxification of oxidants, cell proliferation, cell differentiation and gene expression (Fujii and Ikeda, 2002;Jang et al, 2004).…”