An Arsenate-activated Glutaredoxin from the Arsenic Hyperaccumulator Fern Pteris vittata L. Regulates Intracellular Arsenite

Sundaram, Sabarinath; Rathinasabapathi, Bala; Lena, Q.; Rosen, Barry P.

doi:10.1074/jbc.m704149200

Cited by 82 publications

(60 citation statements)

References 47 publications

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“…Fe-S clusters have been proposed to function as redox sensors for the activation of human GRX2 in the response to oxidative stress (Lillig et al, 2005), suggesting the possible involvement of plant GRXs in oxidative stress sensing or ironsulfur assembly. Pteris vittata GRX5, an arsenate-activated chloroplast-localized CGFS GRX, regulates cellular arsenite levels and arsenic resistance (Sundaram et al, 2008). The CaMV 35S promoter-driven expression of YFP-ROXY1 fusion genes shows a nucleocytoplasmic distribution of ROXY1.…”

Section: Nuclear Activity Of Roxy1 Is Required For Petal Developmentmentioning

confidence: 99%

Nuclear Activity of ROXY1, a Glutaredoxin Interacting with TGA Factors, Is Required for Petal Development inArabidopsis thaliana

et al. 2009

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Glutaredoxins (GRXs) have thus far been associated mainly with redox-regulated processes participating in stress responses. However, ROXY1, encoding a GRX, has recently been shown to regulate petal primorida initiation and further petal morphogenesis in Arabidopsis thaliana. ROXY1 belongs to a land plant-specific class of GRXs that has a CC-type active site motif, which deviates from ubiquitously occurring CPYC and CGFS GRXs. Expression studies of yellow fluorescent protein-ROXY1 fusion genes driven by the cauliflower mosaic virus 35S promoter reveal a nucleocytoplasmic distribution of ROXY1. We demonstrate that nuclear localization of ROXY1 is indispensable and thus crucial for its activity in flower development. Yeast two-hybrid screens identified TGA transcription factors as interacting proteins, which was confirmed by bimolecular fluorescence complementation experiments showing their nuclear interaction in planta. Overlapping expression patterns of ROXY1 and TGA genes during flower development demonstrate that ROXY1/TGA protein interactions can occur in vivo and support their biological relevance in petal development. Deletion analysis of ROXY1 demonstrates the importance of the C terminus for its functionality and for mediating ROXY1/TGA protein interactions. Phenotypic analysis of the roxy1-2 pan double mutant and an engineered chimeric repressor mutant from PERIANTHIA (PAN), a floral TGA gene, supports a dual role of ROXY1 in petal development. Together, our results show that the ROXY1 protein functions in the nucleus, likely by modifying PAN posttranslationally and thereby regulating its activity in petal primordia initiation. Additionally, ROXY1 affects later petal morphogenesis, probably by modulating other TGA factors that might act redundantly during differentiation of second whorl organs.

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Section: Nuclear Activity Of Roxy1 Is Required For Petal Developmentmentioning

confidence: 99%

Nuclear Activity of ROXY1, a Glutaredoxin Interacting with TGA Factors, Is Required for Petal Development inArabidopsis thaliana

et al. 2009

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“…Many genes encoding putative Grx enzymes have been identified in individual plant species [e.g., 31 in Arabidopsis thaliana, (109)], but few biochemical characterizations of expressed Grx proteins have been reported. Grx from spinach (86), rice (113), fern (131), and poplar (107, 108, 110) exhibit activity toward the pro-substrate HEDS in assays containing GSH, GR, and NADPH. In contrast to human Grx enzymes, in which mutation of the C-terminal cysteine in the active site increases activity, the analogous mutation of a poplar Grx decreases deglutathionylation activity by approximately two thirds, suggesting that the side reaction involving Grx intramolecular disulfide formation (Fig.…”

Section: Catalysis Of Deglutathionylation By Other Glutaredoxins and mentioning

confidence: 99%

Mechanistic and Kinetic Details of Catalysis of Thiol-Disulfide Exchange by Glutaredoxins and Potential Mechanisms of Regulation

Gallogly

Starke

Mieyal

2009

Antioxidants & Redox Signaling

203

209

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Glutaredoxins are small, heat-stable proteins that exhibit a characteristic thioredoxin fold and a CXXC=S activesite motif. A variety of glutathione (GSH)-dependent catalytic activities have been attributed to the glutaredoxins, including reduction of ribonucleotide reductase, arsenate, and dehydroascorbate; assembly of iron sulfur cluster complexes; and protein glutathionylation and deglutathionylation. Catalysis of reversible protein glutathionylation by glutaredoxins has been implicated in regulation of redox signal transduction and sulfhydryl homeostasis in numerous contexts in health and disease. This forum review is presented in two parts. Part I is focused primarily on the mechanism of the deglutathionylation reaction catalyzed by prototypical dithiol glutaredoxins, especially human Grx1 and Grx2. Grx-catalyzed protein deglutathionylation proceeds by a nucleophilic, double-displacement mechanism in which rate enhancement is attributed to special reactivity of the low pK a cysteine at its active site, and to increased nucleophilicity of the second substrate, GSH. Glutaredoxins (and Grx domains) have been identified in most organisms, and many exhibit deglutathionylation or other activities or both. Further characterization according to glutathionyl selectivity, physiological substrates, and intracellular roles may lead to subclassification of this family of enzymes. Part II presents potential mechanisms for in vivo regulation of Grx activity, providing avenues for future studies. Antioxid. Redox Signal. 11, 1059-1081.Part I: Glutaredoxins and Catalysis of Thiol-Disulfide Exchange G lutaredoxins are GSH-disulfide oxidoreductases reported to catalyze a variety of GSH-dependent thioldisulfide exchange reactions including protein glutathionylation and deglutathionylation, turnover of ribonucleotide reductase, and reduction of dehydroascorbate and arsenate; and some glutaredoxins are also implicated in FeS cluster homeostasis (reviewed in refs. 68, 80, 81). Among the reported catalytic activities of the glutaredoxins, protein deglutathionylation (reduction of protein-glutathione mixed disulfides, protein-SSG) has received much attention because of its regulatory roles in redox signal transduction and sulfhydryl homeostasis (reviewed in refs. 23, 80). Glutathionylation is an oxidative posttranslational modification that occurs on some protein cysteines under basal conditions [e.g., b-actin (137), mitochondrial complex II (19)]; for others, it is a transient modification that occurs during oxidative stresses such as ischemia=reperfusion [e.g., a-actin (18), GAPDH (26), mitochondrial complex I (56)]. For many proteins, glutathionylation affects function, and thus the reversible glutathionylation of specific proteins has been implicated in regulation of cellular homeostasis in health and disease (reviewed in refs. 23, 80). Grx is the primary intracellular deglutathionylating enzyme in mammalian cells (21,52), and manipulation of Grx levels has been shown to affect protein glutathionylation status and, subs...

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“…CGFS-type Grxs from plants and metazoan are able to perform the functions of Saccharomyces cerevisiae Grx5 (ScGrx5) in the biogenesis of Fe-S clusters in yeast mitochondria (8). However, Plasmodium falciparum glutaredoxinlike protein 1 (PfGLP1) does not bind a Fe-S cluster (9) and in Pteris vittata Grx5 (PvGrx5), the Cys 67 residue at the N-terminal region, not the Cys 108 at the "CGFS" motif, is required for Grx activity and arsenic resistance (10). These results suggest diverse regulation among various CGFS-type Grxs, but the underlying mechanisms remain to be fully investigated.…”

mentioning

confidence: 99%

Structural insights into the N-terminal GIY–YIG endonuclease activity of Arabidopsis glutaredoxin AtGRXS16 in chloroplasts

Liu

Feng

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Glutaredoxins (Grxs) have been identified across taxa as important mediators in various physiological functions. A chloroplastic monothiol glutaredoxin, AtGRXS16 from Arabidopsis thaliana, comprises two distinct functional domains, an N-terminal domain (NTD) with GlyIleTyrTyrIleGly (GIY-YIG) endonuclease motif and a C-terminal Grx module, to coordinate redox regulation and DNA cleavage in chloroplasts. Structural determination of AtGRXS16-NTD showed that it possesses a GIY-YIG endonuclease fold, but the critical residues for the nuclease activity are different from typical GIY-YIG endonucleases. AtGRXS16-NTD was able to cleave λDNA and chloroplast genomic DNA, and the nuclease activity was significantly reduced in AtGRXS16. Functional analysis indicated that AtGRXS16-NTD could inhibit the ability of AtGRXS16 to suppress the sensitivity of yeast grx5 cells to oxidative stress; however, the C-terminal Grx domain itself and AtGRXS16 with a Cys123Ser mutation were active in these cells and able to functionally complement a Grx5 deficiency in yeast. Furthermore, the two functional domains were shown to be negatively regulated through the formation of an intramolecular disulfide bond. These findings unravel a manner of regulation for Grxs and provide insights into the mechanistic link between redox regulation and DNA metabolism in chloroplasts.reactive oxygen species | nuclear magnetic resonance

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An Arsenate-activated Glutaredoxin from the Arsenic Hyperaccumulator Fern Pteris vittata L. Regulates Intracellular Arsenite

Cited by 82 publications

References 47 publications

Nuclear Activity of ROXY1, a Glutaredoxin Interacting with TGA Factors, Is Required for Petal Development inArabidopsis thaliana

Nuclear Activity of ROXY1, a Glutaredoxin Interacting with TGA Factors, Is Required for Petal Development inArabidopsis thaliana

Mechanistic and Kinetic Details of Catalysis of Thiol-Disulfide Exchange by Glutaredoxins and Potential Mechanisms of Regulation

Structural insights into the N-terminal GIY–YIG endonuclease activity of Arabidopsis glutaredoxin AtGRXS16 in chloroplasts

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