Redox regulation of chloroplastic glucose‐6‐phosphate dehydrogenase: A new role for f‐type thioredoxin

Née, Guillaume; Zaffagnini, Mirko; Trost, Paolo; Issakidis‐Bourguet, Emmanuelle

doi:10.1016/j.febslet.2009.07.035

Cited by 101 publications

(73 citation statements)

References 28 publications

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“…However, such effects have often only been demonstrated in vitro , sometimes using oxidant concentrations that are not biologically relevant. Furthermore, the literature contains physiologically relevant counterexamples, such as oxidative activation of chloroplast glucose-6-phosphate dehydrogenase [3,4] and protein kinase signalling cascades [5]. Crucially, the biological relevance of oxidative changes must be understood within the context of cellular functions: loss of activity of a given protein may activate a function at the cellular level.…”

Section: Introductionmentioning

confidence: 99%

Viewing oxidative stress through the lens of oxidative signalling rather than damage

Foyer

Ruban

Noctor

2017

Biochemical Journal

217

126

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Concepts of the roles of reactive oxygen species (ROS) in plants and animals have shifted in recent years from focusing on oxidative damage effects to the current view of ROS as universal signalling metabolites. Rather than having two opposing activities, i.e. damage and signalling, the emerging concept is that all types of oxidative modification/damage are involved in signalling, not least in the induction of repair processes. Examining the multifaceted roles of ROS as crucial cellular signals, we highlight as an example the loss of photosystem II function called photoinhibition, where photoprotection has classically been conflated with oxidative damage.

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Section: Introductionmentioning

confidence: 99%

Viewing oxidative stress through the lens of oxidative signalling rather than damage

Foyer

Ruban

Noctor

2017

Biochemical Journal

217

126

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“…Based on biochemical studies, Trxs f and m are presumed to regulate photosynthesis and carbon metabolism although Trx f seems more efficient than Trx m to redox regulate most enzymes involved in these processes. Trx f specifically activates glyceraldehyde-3-phosphate dehydrogenase (B-containing GAPDH isoforms) and FBPase, and controls the activity of other redox-sensitive enzymes like NADP-MDH and glucose-6-phosphate dehydrogenase (G6PDH; Collin et al, 2003; Lemaire et al, 2007; Marri et al, 2009; Née et al, 2009). Similarly, Trx m reduces enzymes involved in carbon metabolism and catabolism such as NADP-MDH and G6PDH, but also regenerates the activity of enzymes involved in antioxidant mechanisms like Prxs and MSRs (Collin et al, 2003; Vieira Dos Santos et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Overexpression of plastidial thioredoxins f and m differentially alters photosynthetic activity and response to oxidative stress in tobacco plants

Rey¹,

Sanz-Barrio²,

Innocenti³

et al. 2013

Front. Plant Sci.

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Plants display a remarkable diversity of thioredoxins (Trxs), reductases controlling the thiol redox status of proteins. The physiological function of many of them remains elusive, particularly for plastidial Trxs f and m, which are presumed based on biochemical data to regulate photosynthetic reactions and carbon metabolism. Recent reports revealed that Trxs f and m participate in vivo in the control of starch metabolism and cyclic photosynthetic electron transfer around photosystem I, respectively. To further delineate their in planta function, we compared the photosynthetic characteristics, the level and/or activity of various Trx targets and the responses to oxidative stress in transplastomic tobacco plants overexpressing either Trx f or Trx m. We found that plants overexpressing Trx m specifically exhibit altered growth, reduced chlorophyll content, impaired photosynthetic linear electron transfer and decreased pools of glutathione and ascorbate. In both transplastomic lines, activities of two enzymes involved in carbon metabolism, NADP-malate dehydrogenase and NADP-glyceraldehyde-3-phosphate dehydrogenase are markedly and similarly altered. In contrast, plants overexpressing Trx m specifically display increased capacity for methionine sulfoxide reductases, enzymes repairing damaged proteins by regenerating methionine from oxidized methionine. Finally, we also observed that transplastomic plants exhibit distinct responses when exposed to oxidative stress conditions generated by methyl viologen or exposure to high light combined with low temperature, the plants overexpressing Trx m being notably more tolerant than Wt and those overexpressing Trx f. Altogether, these data indicate that Trxs f and m fulfill distinct physiological functions. They prompt us to propose that the m type is involved in key processes linking photosynthetic activity, redox homeostasis and antioxidant mechanisms in the chloroplast.

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“…As the pentose phosphate pathway can either run in its oxidative mode (OPP pathway) to oxidize carbohydrates or in its reductive mode (Calvin-Benson cycle) to fix CO 2 , it is tightly regulated. Zwf plays a central role in the finetuning of the OPP pathway and the Calvin-Benson cycle to prevent futile cycles (7)(8)(9). However, Zwf is not unique to the OPP pathway, as its product 6-P gluconate can also be further metabolized in the ED pathway.…”

mentioning

confidence: 99%

The Entner–Doudoroff pathway is an overlooked glycolytic route in cyanobacteria and plants

Chen

Schreiber

Appel

et al. 2016

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

166

191

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Glucose degradation pathways are central for energy and carbon metabolism throughout all domains of life. They provide ATP, NAD(P)H, and biosynthetic precursors for amino acids, nucleotides, and fatty acids. It is general knowledge that cyanobacteria and plants oxidize carbohydrates via glycolysis [the Embden-Meyerhof-Parnas (EMP) pathway] and the oxidative pentose phosphate (OPP) pathway. However, we found that both possess a third, previously overlooked pathway of glucose breakdown: the Entner-Doudoroff (ED) pathway. Its key enzyme, 2-keto-3-deoxygluconate-6-phosphate (KDPG) aldolase, is widespread in cyanobacteria, moss, fern, algae, and plants and is even more common among cyanobacteria than phosphofructokinase (PFK), the key enzyme of the EMP pathway. Active KDPG aldolases from the cyanobacterium Synechocystis and the plant barley (Hordeum vulgare) were biochemically characterized in vitro. KDPG, a metabolite unique to the ED pathway, was detected in both in vivo, indicating an active ED pathway. Phylogenetic analyses revealed that photosynthetic eukaryotes acquired KDPG aldolase from the cyanobacterial ancestors of plastids via endosymbiotic gene transfer. Several Synechocystis mutants in which key enzymes of all three glucose degradation pathways were knocked out indicate that the ED pathway is physiologically significant, especially under mixotrophic conditions (light and glucose) and under autotrophic conditions in a day/ night cycle, which is probably the most common condition encountered in nature. The ED pathway has lower protein costs and ATP yields than the EMP pathway, in line with the observation that oxygenic photosynthesizers are nutrient-limited, rather than ATP-limited. Furthermore, the ED pathway does not generate futile cycles in organisms that fix CO 2 via the Calvin-Benson cycle. T he breakdown of glucose is central for energy and biosynthetic metabolism throughout all domains of life. The Embden-Meyerhof-Parnas (EMP) pathway (glycolysis) and the oxidative pentose phosphate (OPP) pathway are the backbones of eukaryotic carbon and energy metabolism (1, 2). They generate ATP, NAD(P)H, and biosynthetic precursors for amino acids, nucleotides, and fatty acids. Prokaryotes, in contrast, exhibit a broad diversity in sugar oxidation pathways (3-5). These routes differ in ATP yield, in the enzymes and cofactors involved, and in the chemical intermediates of the pathways. The most common glycolytic routes in prokaryotes are the EMP, ED, and OPP pathways (Fig. 1). The key enzyme unique to the ED pathway is 2-keto-3-deoxygluconate-6-phosphate (KDPG) aldolase (Eda), whereas phosphofructokinase (PFK) is unique to the EMP pathway in the catabolic direction (3, 6). KDPG as a metabolite is exclusively found in the ED pathway (Fig. 1). The first two steps of the OPP pathway are catalyzed by glucose 6-phosphate-dehydrogenase (Zwf) and 6-phosphogluconate dehydrogenase (Gnd). As the pentose phosphate pathway can either run in its oxidative mode (OPP pathway) to oxidize carbohydrates or in its reductive mode ...

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Redox regulation of chloroplastic glucose‐6‐phosphate dehydrogenase: A new role for f‐type thioredoxin

Cited by 101 publications

References 28 publications

Viewing oxidative stress through the lens of oxidative signalling rather than damage

Viewing oxidative stress through the lens of oxidative signalling rather than damage

Overexpression of plastidial thioredoxins f and m differentially alters photosynthetic activity and response to oxidative stress in tobacco plants

The Entner–Doudoroff pathway is an overlooked glycolytic route in cyanobacteria and plants

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