High robustness of cytosolic glutathione redox potential under combined salt and osmotic stress in barley as revealed by the biosensor Grx1-roGFP2

Bohle, Finja; Klaus, Alina; Tegethof, Hendrik; Schwarzländer, Markus; Hochholdinger, Frank; Meyer, Andreas J.; Acosta, Iván F.; Müller-Schüssele, Stefanie J

doi:10.1101/2022.12.22.521445

Cited by 4 publications

(4 citation statements)

References 47 publications

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“…In most cases, the process involves the use of GSSG for a reversible modification of protein cysteinyl residues that can directly modulate a given protein activity [29]. In barley, using a genetically-encoded biosensor of cytosolic glutathione redox potential, this potential was found to be highly robust under combined salt and osmotic stresses [45]. This is consistent with plant UGPase activity being responsive to these stresses [46][47][48].…”

Section: Redox Compounds Affecting Plant Ugpase Activitymentioning

confidence: 69%

Exploring Redox Modulation of Plant UDP-Glucose Pyrophosphorylase

Decker

Aubert

Wilczyńska

et al. 2023

IJMS

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UDP-glucose (UDPG) pyrophosphorylase (UGPase) catalyzes a reversible reaction, producing UDPG, which serves as an essential precursor for hundreds of glycosyltransferases in all organisms. In this study, activities of purified UGPases from sugarcane and barley were found to be reversibly redox modulated in vitro through oxidation by hydrogen peroxide or oxidized glutathione (GSSG) and through reduction by dithiothreitol or glutathione. Generally, while oxidative treatment decreased UGPase activity, a subsequent reduction restored the activity. The oxidized enzyme had increased Km values with substrates, especially pyrophosphate. The increased Km values were also observed, regardless of redox status, for UGPase cysteine mutants (Cys102Ser and Cys99Ser for sugarcane and barley UGPases, respectively). However, activities and substrate affinities (Kms) of sugarcane Cys102Ser mutant, but not barley Cys99Ser, were still prone to redox modulation. The data suggest that plant UGPase is subject to redox control primarily via changes in the redox status of a single cysteine. Other cysteines may also, to some extent, contribute to UGPase redox status, as seen for sugarcane enzymes. The results are discussed with respect to earlier reported details of redox modulation of eukaryotic UGPases and regarding the structure/function properties of these proteins.

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Section: Redox Compounds Affecting Plant Ugpase Activitymentioning

confidence: 69%

Exploring Redox Modulation of Plant UDP-Glucose Pyrophosphorylase

Decker

Aubert

Wilczyńska

et al. 2023

IJMS

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“…While EGSH is usually robust, except under extreme abiotic stress conditions challenging GR capacity (Wagner et al, 2019;Ugalde et al, 2021;Bohle et al, 2022) (Fig. 8), recent results…”

Section: Is Class I Grx Function Relevant In the Chloroplast Stroma?mentioning

confidence: 83%

“…While E GSH is usually robust, except under extreme abiotic stress conditions challenging GR capacity (Wagner et al, 2019; Ugalde et al, 2021; Bohle et al, 2022) ( Fig. 8 ), recent results have shown that stromal E GSH is dynamic in response to physiological light/dark transitions (Müller-Schüssele et al, 2020; Haber et al, 2021).…”

Section: Discussionmentioning

confidence: 95%

Chloroplasts lacking class I glutaredoxins are functional but show a delayed recovery of protein cysteinyl redox state after oxidative challenge

Bohle,

Rossi,

Tamanna

et al. 2023

Preprint

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Redox status of protein cysteinyl residues is mediated via glutathione (GSH)/glutaredoxin (GRX) and thioredoxin (TRX)-dependent redox cascades. An oxidative challenge can induce post-translational protein modifications on thiols, such as proteinS-glutathionylation. Class I GRX are small thiol-disulfide oxidoreductases that reversibly catalyseS-glutathionylation and protein disulfide formation. TRX and GSH/GRX redox systems can provide partial backup for each other in several subcellular compartments, but not in the plastid stroma where TRX/light-dependent redox regulation of primary metabolism takes place. While the stromal TRX system has been studied at detail, the role of class I GRX on plastid redox processesin vivois still unknown. We generate knockout lines ofGRXC5as the only chloroplast class I GRX of the mossPhyscomitrium patens.While we find that class I PpGRXC5 has high activities in glutathione-dependent oxidoreductase assays using hydroxyethyl disulfide or redox-sensitive GFP2 (roGFP2) as substratesin vitro, Δgrxc5plants show no detectable growth defect or stress sensitivity, in contrast to mutants with a less negative stromalEGSH(Δgr1). Using stroma-targeted roGFP2, we show increased protein Cys oxidation and decreased reduction rates after oxidative challenge in Δgrxc5plantsin vivo, indicating kinetic uncoupling of the protein Cys redox state from glutathione redox potential. Protein Cys disulfide andS-glutathionylation formation rates after H2O2treatment remained unchanged. Lack of class I GRX function in the stroma did not result in impaired carbon fixation.Our observations suggest specific roles for class I GRX in the efficient redox equilibration betweenEGSHand protein Cys in the plastid stroma as well as negligible cross-talk with metabolic regulation via the TRX system. We propose a model for stromal class I GRX function as efficient kinetic couplers of protein Cys redox state to the dynamic stromalEGSHand highlight the importance of identifyingin vivotarget proteins of GRXC5.One sentence summaryRemoval of class I GRX activity in the chloroplast stroma ofP. patenskinetically uncouples GRX-dependent cysteine redox changes from the local glutathione redox potential, without an effect on NPQ or photosynthetic carbon reactions.

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“…While E GSH is usually robust, except under extreme abiotic stress conditions challenging GR capacity [ 49 , 62 , 78 ] ( Fig. 8 ), recent results have shown that stromal E GSH is dynamic in response to physiological light/dark transitions [ 40 , 44 ].…”

Section: Discussionmentioning

confidence: 99%

Chloroplasts lacking class I glutaredoxins are functional but show a delayed recovery of protein cysteinyl redox state after oxidative challenge

Bohle,

Rossi,

Tamanna

et al. 2024

Redox Biology

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High robustness of cytosolic glutathione redox potential under combined salt and osmotic stress in barley as revealed by the biosensor Grx1-roGFP2

Cited by 4 publications

References 47 publications

Exploring Redox Modulation of Plant UDP-Glucose Pyrophosphorylase

Exploring Redox Modulation of Plant UDP-Glucose Pyrophosphorylase

Chloroplasts lacking class I glutaredoxins are functional but show a delayed recovery of protein cysteinyl redox state after oxidative challenge

Chloroplasts lacking class I glutaredoxins are functional but show a delayed recovery of protein cysteinyl redox state after oxidative challenge

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