Dynamic rerouting of the carbohydrate flux is key to counteracting oxidative stress

Ralser, Markus; Wamelink, Mirjam M. C.; Kowald, Axel; Gerisch, Birgit; Heeren, Gino; Struys, Eduard A.; Klipp, Edda; Jakobs, Cornelis; Breitenbach, Michael; Lehrach, Hans; Krobitsch, Sylvia

doi:10.1186/jbiol61

Cited by 527 publications

(595 citation statements)

References 55 publications

(74 reference statements)

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“…The redirection is mediated by two different mechanisms that, interestingly, follow each other over time. Initially, GAPDH acts as a metabolic switch upon inactivation and reroutes the metabolic flux by blocking glycolysis, whereas glucose transporters and the PPP remain active [68,69]. This process is very fast; GAPDH is inactivated within seconds and PPP metabolites increase almost immediately [24].…”

Section: Metabolic Transitions Mediate Cellular Adaptationmentioning

confidence: 99%

Regulatory crosstalk of the metabolic network

Grüning

Lehrach

Ralser

2010

Trends in Biochemical Sciences

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The metabolic network has a modular architecture, is robust to perturbations, and responds to biological stimuli and environmental conditions. Through monitoring by metabolite responsive macromolecules, metabolic pathways interact with the transcriptome and proteome. Whereas pathway interconnecting cofactors and substrates report on the overall state of the network, specialised intermediates measure the activity of individual functional units. Transitions in the network affect many of these regulatory metabolites, facilitating the parallel regulation of the timing and control of diverse biological processes. The metabolic network controls its own balance, chromatin structure and the biosynthesis of molecular cofactors; moreover, metabolic shifts are crucial in the response to oxidative stress and play a regulatory role in cancer.Evolution of the metabolic network and its structure Life probably began with the formation of compartmentalised autocatalytic chemical cycles. With the appearance of complex catalysts (ribonucleic acid-or protein-based enzymes), these cycles gained complexity, and evolved in their effectiveness and robustness [1]. These metabolic pathways now form the basis for life.As was the case for the first primitive life forms, the survival of today's complex organisms depends on the robustness and functionality of the metabolic framework [2]. To prevent and counteract perturbations in the flux, many biological control and sensor systems have evolved around the metabolic network. Metabolic pathways provide the cell with energy and supply macromolecular synthesis pathways with their required intermediates. They also balance metabolic systems under a variety of physiological conditions, and act as transducers and sensor systems for environmental conditions and stimuli. In addition, metabolic pathways are essential for crosstalk between metabolic regulatory components and the cellular transcriptome and proteome.As early as the 1960s, the principle that cells alter their gene expression in response to metabolic requirements has been known. The seminal work of Jacob and Monod, investigating the lac operon, uncovered one of the first examples of chemical-genetic regulation, by which bacterial cells adjust their enzyme production to the nutrient supply [3]. However, only recently have the broader implications of this principle emerged. Indeed, changes in the metabolic network not only control the metabolome, but they also have wide-ranging regulatory functions throughout biology.Most of the biochemical mechanisms that link the metabolic network to the transcriptome and proteome are incompletely understood. However, one type of regulation appears to be common: representative network intermediates bind to and modulate sensor function and activity of transcription factors, translational regulators, chromatin, enzymes, RNA molecules, and ion channels. Significant transcriptional changes around these intermediates identified them as reporter metabolites [4,5]. The use of intermediates as activity reporters ne...

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Section: Metabolic Transitions Mediate Cellular Adaptationmentioning

confidence: 99%

Regulatory crosstalk of the metabolic network

Grüning

Lehrach

Ralser

2010

Trends in Biochemical Sciences

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“…Data were obtained for all PPP isoenzymes, with the exception of SOL3 and SOL4 which showed no activity (see Table 1). Any missing kinetic parameters were taken from previous models [Vaseghi et al, 1999, Ralser et al, 2007, or given initial estimates using typical values (kcat = 10 s −1 , Km = 0.1 mM, [Bar-Even et al, 2011). …”

Section: Kineticsmentioning

confidence: 99%

“…In response to high oxidant levels this enzyme is inactivated and accumulates in the nucleus of the cell in several organisms and cell types [Chuang et al, 2005, Shenton & Grant, 2003]. Thus, we simulate in silico oxidative stress through reduction of TDH activity in the combined glycolysis:PPP model to 25% of its wild-type value, following the approach of [Ralser et al, 2007]. Cells also respond to the presence of oxidative agents through slower growth, which we translate in our model as reducing the requirement for E4P and R5P (the biomass precursors); we thus reduce the rate of consumption of these by two orders of magnitude from their reference values.…”

Section: Oxidative Stressmentioning

confidence: 99%

“…Cells typically respond with post-translational modification of a number of proteins, affecting both their localisation and functionality [Godon et al, 1998, Ishii et al, 2007. In particular, oxidative stress in yeast leads to repression of glycolysis and induction of the PPP; this is crucial for maintaining the NADPH/NADP + ratio, which provides the redox power for antioxidant systems [Ralser et al, 2007].…”

Section: Introductionmentioning

confidence: 99%

“…Mathematical models of the pathway have been created in yeast [Vaseghi et al, 1999, Ralser et al, 2007, trypanosome [Kerkhoven et al, 2013], rat [Haut et al, 1974, Sabate et al, 1995 and human [Joshi & Palsson, 1989, Mulquiney & Kuchel, 1999. However, such studies have neglected, or over-simplified, the non-oxidative branch of the pathway.…”

Section: Introductionmentioning

confidence: 99%

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Enzyme characterisation and kinetic modelling of the pentose phosphate pathway in yeast

Messiha

Kent

Malys

et al. 2013

Preprint

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We present the quantification and kinetic characterisation of the enzymes of the pentose phosphate pathway in Saccharomyces cerevisiae. The data are combined into a mathematical model that describes the dynamics of this system and allows for predicting changes in metabolite concentrations and fluxes in response to perturbations. We use the model to study the response of yeast to a glucose pulse. We then combine the model with an existing glycolysis one to study the effect of oxidative stress on carbohydrate metabolism. The combination of these two models was made possible by the standardized enzyme kinetic experiments carried out in both studies. This work demonstrates the feasibility of constructing larger network models by merging smaller pathway models.

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Glyceraldehyde‐3‐phosphate dehydrogenase from Citrobacter sp. S‐77 is post‐translationally modified by CoA (protein CoAlation) under oxidative stress

2018

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Protein CoAlation (S‐thiolation by coenzyme A) has recently emerged as an alternative redox‐regulated post‐translational modification by which protein thiols are covalently modified with coenzyme A (CoA). However, little is known about the role and mechanism of this post‐translational modification. In the present study, we investigated CoAlation of glyceraldehyde‐3‐phosphate dehydrogenase ( GAPDH ) from a facultative anaerobic Gram‐negative bacterium Citrobacter sp. S‐77 ( Cb GAPDH ). GAPDH is a key glycolytic enzyme whose activity relies on the thiol‐based redox‐regulated post‐translational modifications of active‐site cysteine. LC ‐ MS / MS analysis revealed that CoAlation of Cb GAPDH occurred in vivo under sodium hypochlorite (Na OC l) stress. The purified Cb GAPDH was highly sensitive to overoxidation by H 2 O 2 and Na OC l, which resulted in irreversible enzyme inactivation. By contrast, treatment with coenzyme A disulphide (Co ASSC oA) or H 2 O 2 /Na OC l in the presence of CoA led to CoAlation and inactivation of the enzyme; activity could be recovered after incubation with dithiothreitol, glutathione and CoA. CoAlation of the enzyme in vitro was confirmed by mass spectrometry. The presence of a substrate, glyceraldehyde‐3‐phosphate, fully protected Cb GAPDH from inactivation by CoAlation, suggesting that the inactivation is due to the formation of mixed disulphides between CoA and the active‐site cysteine Cys149. A molecular docking study also supported the formation of mixed disulphide without steric constraints. These observations suggest that CoAlation is an alternative mechanism to protect the redox‐sensitive thiol (Cys149) of Cb GAPDH against irreversible oxidation, thereby regulating enzyme activity under oxidative stress.

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Dynamic rerouting of the carbohydrate flux is key to counteracting oxidative stress

Cited by 527 publications

References 55 publications

Regulatory crosstalk of the metabolic network

Regulatory crosstalk of the metabolic network

Enzyme characterisation and kinetic modelling of the pentose phosphate pathway in yeast

Glyceraldehyde‐3‐phosphate dehydrogenase from Citrobacter sp. S‐77 is post‐translationally modified by CoA (protein CoAlation) under oxidative stress

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