Thioredoxin targets in plants: The first 30 years

Montrichard, Françoise; Alkhalfioui, Fatima; Yano, Hiroyuki; Vensel, William H.; Hurkman, William J.; Buchanan, Bob B.

doi:10.1016/j.jprot.2008.12.002

Cited by 265 publications

(255 citation statements)

References 132 publications

Supporting

Mentioning

248

Contrasting

Unclassified

Order By: Relevance

“…The value of 550 M −1 s −1 obtained for the wt is to the best of our knowledge the first disulfide reduction rate reported for one of the very large number of plant Trx targets identified in proteomic screens. 11 Activity was reduced to a greater extent in M88 than in A106 mutants ( Figure 3 and Table 3). M88G, M88A, and M88L showed 5, 30, and 75% of wt activity toward BASI, respectively, whereas M88P completely lost activity; i.e., no detectable signal was obtained above the background level of NADPH oxidation (0.002 Δ340 min −1 ), which represents the HvNTR2-dependent reduction of oxygen.…”

Section: ■ Resultsmentioning

confidence: 99%

Dissecting Molecular Interactions Involved in Recognition of Target Disulfides by the Barley Thioredoxin System

et al. 2012

View full text Add to dashboard Cite

Thioredoxin reduces disulfide bonds, thus regulating activities of target proteins in various biological systems, e.g., inactivation of inhibitors of starch hydrolases and proteases in germinating plant seeds. In the three-dimensional structure of a complex with barley α-amylase/subtilisin inhibitor (BASI), two loops in barley thioredoxin h2 (HvTrxh2), containing an invariant cis-proline ( 86 EAMP 89 ) and a conserved glycine ( 104 VGA 106 ), surround the active site cysteines ( 45 WCGPC 49 ) and contribute to binding of BASI through backbone−backbone hydrogen bonds [Maeda, K., Hagglund, P., Finnie, C., Svensson, B., and Henriksen, A. ( 2006) Structure 14, 1701−1710]. This study involves mutational analysis of key amino acid residues from these two loops in reactions with three protein disulfide substrates, BASI, barley glutathione peroxidase, and bovine insulin as well as with NADPH-dependent barley thioredoxin reductase. HvTrxh2 M88G and M88A adjacent to the invariant cis-proline lost efficiency in both BASI disulfide reduction and recycling by thioredoxin reductase. These effects were further pronounced in M88P lacking a backbone NH group. Remarkably, HvTrxh2 E86R in the same loop displayed overall retained catalytic properties, with the exception of a 3-fold increased activity toward BASI. From the 104 VGA 106 loop, a backbone hydrogen bond donated by A106 appears to be important for target disulfide recognition as A106P lost 90% activity toward BASI but was efficiently recycled by thioredoxin reductase. The findings support important roles in target recognition of backbone−backbone hydrogen bond and electrostatic interactions and are discussed in relation to earlier structural and functional studies of thioredoxins and related proteins.

show abstract

Section: ■ Resultsmentioning

confidence: 99%

Dissecting Molecular Interactions Involved in Recognition of Target Disulfides by the Barley Thioredoxin System

et al. 2012

View full text Add to dashboard Cite

show abstract

“…These potential NTRC targets were identified by mass spectrometry, N-terminal sequence analysis, and/or immunoblotting. The results revealed that NTRC can associate with several currently known Trx target candidates (11). An unexpected and notable NTRC target was Trx-z; Trx-z bound to NTRC C457S , whereas Trx-f and Trx-m did not.…”

Section: Significancementioning

confidence: 99%

“…Other putative redox-mediator proteins, including several Trx-like proteins and glutaredoxins, were also reported to be localized in chloroplasts (5,6). Furthermore, recently developed proteomic techniques and methodologies for screening Trx target proteins have identified potential redox-regulated proteins associated with a broad spectrum of chloroplast functions (7)(8)(9)(10)(11). These advances suggest that chloroplasts have a complex redox network composed of divergent pathways rather than a simple onedirectional cascade.…”

mentioning

confidence: 99%

Two distinct redox cascades cooperatively regulate chloroplast functions and sustain plant viability

Yoshida

Hisabori

2016

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

123

182

View full text Add to dashboard Cite

The thiol-based redox regulation system is believed to adjust chloroplast functions in response to changes in light environments. A redox cascade via the ferredoxin-thioredoxin reductase (FTR)/thioredoxin (Trx) pathway has been traditionally considered to serve as a transmitter of light signals to target enzymes. However, emerging data indicate that chloroplasts have a complex redox network composed of diverse redox-mediator proteins and target enzymes. Despite extensive research addressing this system, two fundamental questions are still unresolved: How are redox pathways orchestrated within chloroplasts, and why are chloroplasts endowed with a complicated redox network? In this report, we show that NADPH-Trx reductase C (NTRC) is a key redox-mediator protein responsible for regulatory functions distinct from those of the classically known FTR/Trx system. Target screening and subsequent biochemical assays indicated that NTRC and the Trx family differentially recognize their target proteins. In addition, we found that NTRC is an electron donor to Trx-z, which is a key regulator of gene expression in chloroplasts. We further demonstrate that cooperative control of chloroplast functions via the FTR/Trx and NTRC pathways is essential for plant viability. Arabidopsis double mutants impaired in FTR and NTRC expression displayed lethal phenotypes under autotrophic growth conditions. This severe growth phenotype was related to a drastic loss of photosynthetic performance. These combined results provide an expanded map of the chloroplast redox network and its biological functions.T o preserve the integrity and efficiency of photosynthesis and other metabolic reactions, chloroplast enzymes need to be flexibly and appropriately controlled in response to changes in light environments. The photosynthetic electron transport chain in the chloroplast thylakoid membrane converts light energy into chemical energy, which is captured and stored in ATP and NADPH. These molecules are primarily consumed by the Calvin-Benson cycle in the stroma, but part of the reducing power is used for other metabolic reactions in chloroplasts (e.g., nitrogen and sulfur metabolism). One pathway for the reducing power is the redox cascade, mediated by ferredoxin-thioredoxin reductase (FTR) and thioredoxin (Trx). In this system, FTR receives reducing power from the light-driven photosynthetic electron transport chain via ferredoxin and then donates the reducing power to Trx. A reduced form of Trx subsequently transfers reducing power to target proteins through a dithiol-disulfide exchange reaction, allowing the targets to modulate the enzymatic activities. The redox cascade via the FTR/Trx pathway provides the basis for thiol-based redox regulation in chloroplasts and ensures light-responsive control of chloroplast functions (1, 2).The FTR/Trx pathway has been considered the only pathway regulating redox reactions in chloroplasts. Information about its target proteins has also been limited to a specific set of lightactivated enzymes, such as some enzy...

show abstract

“…This strong effect on GDC and SHM1 is remarkable because these enzymes represent an important intersection between photorespiration, amino acid metabolism, and one-carbon metabolism , and it is controlled by a range of different mechanisms. For example, GDC activity itself is inhibited by Ser (Oliver and Sarojini, 1987) and controlled by the NADH/NAD + ratio (Bourguignon et al, 1988) and other components of cellular redox regulation (Balmer et al, 2004;Montrichard et al, 2009). Moreover, overexpression of the H-protein of GDC resulted in 30% lower Gly levels in Arabidopsis and a reduction in the levels of several upstream and downstream metabolites such as glycerate or glycolate (Timm et al, 2012a), which underlines the importance and controlling character of GDC as photorespiration's "centerpiece.…”

Section: Ser Rather Than Gly As a Possible Metabolic Signal For The Tmentioning

confidence: 99%

Serine Acts as a Metabolic Signal for the Transcriptional Control of Photorespiration-Related Genes in Arabidopsis

et al. 2013

View full text Add to dashboard Cite

Photosynthetic carbon assimilation including photorespiration is dynamically regulated during the day/night cycle. This includes transcriptional regulation, such as the light induction of corresponding genes, but little is known about the contribution of photorespiratory metabolites to the regulation of gene expression. Here, we examined diurnal changes in the levels of photorespiratory metabolites, of enzymes of the photorespiratory carbon cycle, and of corresponding transcripts in wild-type plants of Arabidopsis (Arabidopsis thaliana) and in a mutant with altered photorespiratory flux due to the absence of the peroxisomal enzyme Hydroxypyruvate Reductase1 (HPR1). Metabolomics of the wild type showed that the relative amounts of most metabolites involved in photorespiration increased after the onset of light, exhibited maxima at the end of the day, and decreased during the night. In accordance with those findings, both the amounts of messenger RNAs encoding photorespiratory enzymes and the respective protein contents showed a comparable accumulation pattern. Deletion of HPR1 did not significantly alter most of the metabolite patterns relative to wild-type plants; only serine accumulated to a constitutively elevated amount in this mutant. In contrast, the hpr1 mutation resulted in considerable deregulation of the transcription of photorespiration-related genes. This transcriptional deregulation could also be induced by the external application of L-serine but not glycine to the Arabidopsis wild type, suggesting that serine acts as a metabolic signal for the transcriptional regulation of photorespiration, particularly in the glycine-to-serine interconversion reactions.

show abstract

Thioredoxin targets in plants: The first 30 years

Cited by 265 publications

References 132 publications

Dissecting Molecular Interactions Involved in Recognition of Target Disulfides by the Barley Thioredoxin System

Dissecting Molecular Interactions Involved in Recognition of Target Disulfides by the Barley Thioredoxin System

Two distinct redox cascades cooperatively regulate chloroplast functions and sustain plant viability

Serine Acts as a Metabolic Signal for the Transcriptional Control of Photorespiration-Related Genes in Arabidopsis

Contact Info

Product

Resources

About