S-Nitrosylation of Peroxiredoxin II E Promotes Peroxynitrite-Mediated Tyrosine Nitration

Abstract

Nitric oxide (NO) is a free radical product of cell metabolism that plays diverse and important roles in the regulation of cellular function. S-Nitrosylation is emerging as a specific and fundamental posttranslational protein modification for the transduction of NO bioactivity, but very little is known about its physiological functions in plants. We investigated the molecular mechanism for S-nitrosylation of peroxiredoxin II E (PrxII E) from Arabidopsis thaliana and found that this posttranslational modification inhibits the hydroperoxide-reducing peroxidase activity of PrxII E, thus revealing a novel regulatory mechanism for peroxiredoxins. Furthermore, we obtained biochemical and genetic evidence that PrxII E functions in detoxifying peroxynitrite (ONOO À ), a potent oxidizing and nitrating species formed in a diffusion-limited reaction between NO and O 2 À that can interfere with Tyr kinase signaling through the nitration of Tyr residues. S-Nitrosylation also inhibits the ONOO À detoxification activity of PrxII E, causing a dramatic increase of ONOO À -dependent nitrotyrosine residue formation. The same increase was observed in a prxII E mutant line after exposure to ONOO À , indicating that the PrxII E modulation of ONOO À bioactivity is biologically relevant. We conclude that NO regulates the effects of its own radicals through the S-nitrosylation of crucial components of the antioxidant defense system that function as common triggers for reactive oxygen species-and NO-mediated signaling events.

Multilevel Regulation of 2-Cys Peroxiredoxin Reaction Cycle by S-Nitrosylation

“…For example, in a number of experimental models, NO or nitrosative stress induces the expression of specific Prxs, including Prx1 (39,40). Other recent studies have indicated that S(NO) can directly modulate several members of the Prx family by means of S-nitrosylation (19,20,23). In this study we provided additional mechanistic insights into the regulation of a 2-Cys Prx by SNO.…”

“…In neuronal cells, nitrosylation of Prx2 has been shown to inhibit its activity and thereby to contribute to oxidative stress and cellular damage (19). Nitrosylation likewise inhibits the activity of plant Prx II E (20). Prx1 was found to be nitrosylated in endotoxin-stimulated macrophages (21,22), and recent studies indicate that nitrosylation protects Prx1 from over-oxidation (23).…”

The Arabidopsis PARAQUAT RESISTANT2 gene encodes an S-nitrosoglutathione reductase that is a key regulator of cell death

“…In particular, S-nitrosylation of peroxiredoxin II E has been demonstrated to inhibit its activity involved in hydroperoxide reduction and peroxynitrite detoxification [37], and S-nitrosylation of NPR1 is critical for the regulation of redox-based conformational changes that directly determine the NPR1 activity [35]. In addition, the Arabidopsis METACASPASE9 activity is regulated by S-nitrosylation, providing a possible link between the redox-based posttranslational modification mechanism and biochemical execution of cell death in plant cells [38].…”

“…Moreover, S-nitrosylation, the covalent addition of an NO molecule to a cysteine thiol of a protein or a peptide, is a key destination of the gaseous hormone and a redox-based posttranslational modification mechanism. S-nitrosylation appears to be an important mechanism to regulate the activity and stability of many proteins and enzymes [24,[34][35][36][37][38]. In this complicated, yet not well-understood process, S-nitrosoglutathione (GSNO), derived by S-nitrosylation of the antioxidant tripeptide glutathione, is a major reservoir of biologically active NO.…”

Le monoxyde d’azote

“…À ce jour, une cinquantaine de protéines S-nitrosylées a ainsi été identifiée, dont une dizaine ont fait l'objet d'études fonctionnelles approfondies (Tableau I). Il ressort de ces études que la S-nitrosylation module l'activité de ces protéines en ciblant directement des résidus Cys de sites actifs [24][25][26][27][28], en promouvant la formation de ponts disulfures [29,30], et en bloquant la fixation de cofacteurs (FAD ou ATP) par encombrement stérique [31,32]. Les données acquises pour les protéines NPR1 (nonexpressor of pathogenesis-related gene 1) et RBOHD (respiratory burst oxidase homologue D) sont détaillées ci-dessous à titre d'exemple (Figure 2).…”