Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ATP consumption”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17Linked to original sources
PubMed2004

Reactive oxygen species and phosphatidylserine externalization in murine sickle red cells.

Due to their role in oxygen transport and the presence of redox active haemoglobin molecules, red blood cells (RBC) generate relatively high levels of reactive oxygen species (ROS). To counteract the potential deleterious effects of ROS, RBCs have a well-integrated network of anti-oxidant mechanisms to combat this oxidative stress. ROS formation is increased in sickle-cell disease (SCD) and our studies in a murine SCD model showed a significant increase in the generation of ROS when compared with normal mice. Our data also indicated that murine sickle RBCs exhibit a significantly increased ATP catabolism, partly due to the increased activity of glucose-6-phosphate dehydrogenase and glutathione reductase to regenerate intracellular glutathione (GSH) levels to neutralize the adverse milieu of oxidative stress. Higher ATP consumption by the murine sickle RBCs, together with the increased ROS formation and impairment of the aminophospholipid translocase or flipase may underlie the exposure of phosphatidylserine on the surface of these cells.

Adenosine Triphosphate↗
PubMed1999

Weak-acid preservatives: modelling microbial inhibition and response.

Weak-acid preservatives are widely used to prevent microbial spoilage of acidic foods and beverages. Characteristically, weak-acid preservatives do not kill micro-organisms but inhibit growth, causing very extended lag phases. Preservatives are more effective at low pH values where solutions contain increased concentrations of undissociated acids. Inhibition by weak-acids involves rapid diffusion of undissociated molecules through the plasma membrane; dissociation of these molecules within cells liberates protons, thus acidifying the cytoplasm and preventing growth. By modelling preservative action in yeast, using a thermodynamic and kinetic approach, it was possible to demonstrate that: (i) inhibition depends more on the degree to which individual preservatives are concentrated within cells, rather than on undissociated acid concentration per se; (ii) it is entirely feasible for microbes to pump protons out of the cell during extended lag phase and raise internal pH (pHi), despite further influx of preservatives; (iii) the duration of the lag phase can be predicted from the model, using a Gaussian fit of proton-pumping H(+)-ATPase activity against pHi; (iv) theoretical ATP consumption for proton pumping can be directly correlated with the reduction in cell yield observed in glucose-limited cultures.

Acids, Acyclic↗
PubMed1978

Nerve growth factor potentiates actomyosin adenosinetriphosphatase.

The nerve growth factor protein (NGF) favors polymerization of brain actin and induces its organization to form paracrystalline structures that activate myosin ATPase (ATP phosphohydrolase, EC 3.6.1.3) to an extent greater than actin alone. Binding studies show that the initial 1:1 stoichiometry of NGF-G-actin complexes decreases to 1:7-10 when polymerization is ended and paracrystalline structures are formed. The ratio becomes even lower when heavy meromyosin is added in the absence of ATP, suggesting that heavy meromyosin displaces NGF bound to actin microfilaments. This conclusion is supported by the finding that when heavy meromyosin is added to NGF-microfilament complexes, under conditions for "decorating" microfilaments, the usual paracrystalline structure of the complexes disappears. The NGF-mediated organization of actin and activation of myosin ATPase is visualized as a self-regulatory and self-propagating mechanism, because progressive displacement of the growth factor induced by heavy meromyosin binding to F actin as ATP consumption proceeds renders an increasingly higher amount of NGF free for new interactions. These findings are discussed in the light of the mechanism of action of NGF in the target cells.

Actins↗
PubMed2001

Cellular energetics in the preconditioned state: protective role for phosphotransfer reactions captured by 18O-assisted 31P NMR.

Cell survival is critically dependent on the preservation of cellular bioenergetics. However, the metabolic mechanisms that confer resistance to injury are poorly understood. Phosphotransfer reactions integrate ATP-consuming with ATP-producing processes and could thereby contribute to the generation of a protective phenotype. Here, we used ischemic preconditioning to induce a stress-tolerant state and (18)O-assisted (31)P nuclear magnetic resonance spectroscopy to capture intracellular phosphotransfer dynamics. Preconditioning of isolated perfused hearts triggered a redistribution in phosphotransfer flux with significant increase in creatine kinase and glycolytic rates. High energy phosphoryl fluxes through creatine kinase, adenylate kinase, and glycolysis in preconditioned hearts correlated tightly with post-ischemic functional recovery. This was associated with enhanced metabolite exchange between subcellular compartments, manifested by augmented transfer of inorganic phosphate from cellular ATPases to mitochondrial ATP synthase. Preconditioning-induced energetic remodeling protected cellular ATP synthesis and ATP consumption, improving contractile performance following ischemia-reperfusion insult. Thus, the plasticity of phosphotransfer networks contributes to the effective functioning of the cellular energetic system, providing a mechanism for increased tolerance toward injury.

Adenosine Triphosphate↗
PubMed2005

Activation of myosin Va function by melanophilin, a specific docking partner of myosin Va.

It is known that melanophilin is a myosin Va-targeting molecule that links myosin Va and the cargo vesicles in cells. Here we found that melanophilin directly activates the actin-activated ATPase activity of myosin Va and thus its motor activity. The actin-activated ATPase activity of the melanocyte-type myosin Va having exon-F was significantly activated by melanophilin by 4-fold. Although Rab27a binds to myosin Va/melanophilin complex, it did not affect the melanophilin-induced activation of myosin Va. Deletion of the C-terminal actin binding domain and N-terminal Rab binding domain of melanophilin resulted in no change in the activation of the ATPase by melanophilin, indicating that the myosin Va binding domain (MBD) is sufficient for the activation of myosin Va. Among MBDs, the interaction of MBD-2 with exon-F of myosin Va is critical for the binding of myosin Va and melanophilin, whereas MBD-1 interacting with the globular tail of myosin Va plays a more significant role in the activation of myosin Va ATPase activity. This is the first demonstration that the binding of the cargo molecule directly activates myosin motor activity. The present finding raises the idea that myosin motors are switched upon their binding to the cargo molecules, thus avoiding the waste of ATP consumption.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Modulation of the viral ATPase activity by the portal protein correlates with DNA packaging efficiency.

DNA packaging in tailed bacteriophages and herpesviruses requires assembly of a complex molecular machine at a specific vertex of a preformed procapsid. As in all these viruses, the DNA translocation motor of bacteriophage SPP1 is composed of the portal protein (gp6) that provides a tunnel for DNA entry into the procapsid and of the viral ATPase (gp1-gp2 complex) that fuels DNA translocation. Here we studied the cross-talk between the components of the motor to control its ATP consumption and DNA encapsidation. We showed that gp6 embedded in the procapsid structure stimulated more than 10-fold the gp2 ATPase activity. This stimulation, which was significantly higher than the one conferred by isolated gp6, depended on the presence of gp1. Mutations in different regions of gp6 abolished or decreased the gp6-induced stimulation of the ATPase. This effect on gp2 activity was observed both in the presence and in the absence of DNA and showed a strict correlation with the efficiency of DNA packaging into procapsids containing the mutant portals. Our results demonstrated that the portal protein has an active control over the viral ATPase activity that correlates with the performance of the DNA packaging motor.

Adenosine Triphosphatases↗
PubMed2006

Inhibition of hepatic phosphatidylcholine synthesis by 5-aminoimidazole-4-carboxamide-1-beta-4-ribofuranoside is independent of AMP-activated protein kinase activation.

5-Aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAr), a commonly used indirect activator of AMP-activated protein kinase (AMPK), inhibits phosphatidylcholine (PC) biosynthesis in freshly isolated hepatocytes. In all nucleated mammalian cells, PC is synthesized from choline via the Kennedy (CDP-choline) pathway. The purpose of our study was to provide direct evidence that AMPK regulates phospholipid biosynthesis and to elucidate the mechanism(s) by which AMPK inhibits hepatic PC synthesis. Incubations of hepatocytes with AICAr resulted in a dose-dependent activation of AMPK and inhibition of PC biosynthesis. Surprisingly, adenoviral delivery of constitutively active AMPK did not alter PC biosynthesis. In addition, expression of dominant negative mutants of AMPK was unable to block the AICAr-dependent inhibition of PC biosynthesis, indicating that AICAr was acting independently of AMPK activation. Determination of aqueous intermediates of the CDP-choline pathway indicated that choline kinase, the first enzyme in the pathway, was inhibited by AICAr administration. Flux through the CDP-choline pathway was directly correlated to the level of intracellular ATP concentrations. Therefore, it is possible that inhibition of PC biosynthesis is another process by which the cell can reduce ATP consumption in times of energetic stress. However, unlike cholesterol and triacylglycerol biosynthesis, PC production is not regulated by AMPK.

AMP-Activated Protein Kinases↗
PubMed1994

Nitric oxide opens ATP-sensitive K+ channels through suppression of phosphofructokinase activity and inhibits glucose-induced insulin release in pancreatic beta cells.

Nitric oxide (NO) is known to be a potent messenger in the intracellular signal transduction system in many tissues. In pancreatic beta cells, NO has been reported to be formed from L-arginine through NO synthase. To elucidate the effect of NO on insulin secretion and to investigate the intracellular mechanism of its effect, we have used sodium nitroprusside (SNP) as a NO donor. SNP inhibited glucose-induced insulin secretion in a dose-dependent manner, and its effect was reversed by hemoglobin, a known NO scavenger. However, glyceraldehyde-induced insulin secretion was not affected by SNP. Since the closure of ATP-sensitive K+ channels (KATP channel) has been established as a key step in glucose-induced insulin secretion, we have directly assessed the effect of SNP on KATP channel activity using the patch clamp technique. The KATP channel activity reduced by glucose was found to be reversibly activated by the addition of SNP, and this activation was able to be similarly reproduced by applying S-Nitroso-N-acetyl-DL-penicillamine (SNAP), another NO generator. Furthermore, these activating effects were completely eliminated by hemoglobin, in accordance with the reversibility in inhibition of glucose-induced insulin release. However, SNP could not affect the KATP channel suppression by ATP applied to the inside of the plasma membrane. The activation of the KATP channel by NO, therefore, seems to be due to the decreased ATP production attributable to impairment of glucose metabolism in beta cells. Since SNP exhibited no effect on glyceraldehyde-induced KATP channel inhibition, NO may disturb a glycolytic step before glyceraldehyde-3-phosphate. The KATP channel activation by 2-deoxyglucose through presumable ATP consumption due to its phosphorylation by glucokinase was, however, not affected even in the presence of SNP. But in the permeabilized beta cells made by exposure to a low concentration (0.02 U/ml) of streptolysin O (open cell-attached configuration), SNP reopens KATP channels which have been eliminated by fructose-6-phosphate, while this effect was not observed in the KATP channels inhibited by fructose-1,6-bisphosphate. On the other hand, in rat ventricular myocyte KATP channels were not activated by SNP even under a low concentration of glucose. From these observations, the inhibition of phosphofructokinase activity is probably the site responsible for the impairment of glucose metabolism induced by NO in pancreatic beta cells. NO, therefore, seems to be a factor in the deterioration of glucose-induced insulin secretion from pancreatic beta cells through a unique intracellular mechanism.

Adenosine Triphosphate↗
PubMed2006

Monoclonal antibody FsC-47 against carp sperm creatine kinase.

The enzyme creatine kinase (CK) plays a key role in energy homeostasis of cells with high and fluctuating energy requirements. As for spermatozoa, the activity of phosphocreatine shuttle, which directs energy from the mitochondria to sites of ATP consumption, is dependent on individual species. High activities of CK are observed in spermatozoa of nonvertebrate, fish, and birds, contrary to the low-level CK activity in mammalian spermatozoa. A new monoclonal antibody (MAb) to carp sperm creatine kinase was prepared. This antibody is applicable to large-scale immunochemical techniques. In this study, it was applied to the study of carp sperm motility, and the evaluation of the influence of CK on the quality and fertilization ability of carp spermatozoa.

Animals↗
PubMed2001

Protection of the photosynthetic apparatus against damage by excessive illumination in homoiohydric leaves and poikilohydric mosses and lichens.

Experimental work on the control of photosystem II in the photosynthetic apparatus of higher plants, mosses and lichens is reviewed on a background of current literature. Transmembrane proton transport during photoassimilatory and photorespiratory electron flows is considered insufficient for producing the intrathylakoid acidification necessary for control of photosystem II activity under excessive illumination. Oxygen reduction during the Mehler reaction is slow. Together with associated reactions (the water-water cycle), it poises the electron transport chain for coupled cyclic electron transport rather than acting as an efficient electron sink. Coupled electron transport not accompanied by ATP consumption in associated reactions provides the additional thylakoid acidification needed for the binding of zeaxanthin to a chlorophyll-containing thylakoid protein. This results in the formation of energy-dissipating traps in the antennae of photosystem II. Competition for energy capture decreases the activity of photosystem II. In hydrated mosses and lichens, but not in leaves of higher plants, protein protonation and zeaxanthin availability are fully sufficient for effective energy dissipation even when photosystem II reaction centres are open. In leaves, an additional light reaction is required, and energy dissipation occurs not only in the antennae but also in reaction centres. Loss of chlorophyll fluorescence during the drying of predarkened poikilohydric mosses and lichens indicates energy dissipation in the dry state which is unrelated to protonation and zeaxanthin availability. Excitation of photosystem II by sunlight is not destructive in these dry organisms, whereas photosystem II activity of dried leaves is rapidly lost under strong illumination.

Adaptation, Physiological↗
PubMed1998

Mutation of cis-proline 207 in mitochondrial creatine kinase to alanine leads to increased acid stability.

We show that the mutation of an uncharged residue far from the active site to another uncharged residue can have effects on the active site without disturbing the overall structure of the protein. Cis-proline 207 of mitochondrial creatine kinase was mutated to alanine. The mutant showed a decrease in the pH-optimum for ATP synthesis by 1.5 units while the maximum relative activity was lowered to 53% of the wild-type enzyme. In the direction of ATP consumption, the pH optimum was lowered by 1.3 units and the maximum relative activity was 49% of the wild-type enzyme. The enzyme kinetic parameters Km and Kd for the substrates did not change dramatically, indicating a largely unperturbed active site. Small-angle X-ray scattering was used to investigate the structural change concomitant with the mutation, yielding a scattering profile only slightly different from that of the wild-type enzyme. Neither the radius of gyration nor the molecular mass showed any significant differences, leading to the conclusion that quarternary organization and fold of the mutant and the wild-type enzymes were similar. Theoretical analysis suggests the most probable primary source of structural change to be a transition of residue 207 peptide bond torsional angle co from the cis to the trans configuration.

Creatine Kinase↗
PubMed1994

What is special about smooth muscle? The significance of covalent crossbridge regulation.

Knowledge of the molecular mechanisms involved in chemomechanical transduction and the regulatory elements determining contraction and relaxation are largely derived from cross-striated muscle. However, it has become clear that vertebrate smooth muscles have features lacking in striated muscle. These derive from regulated crossbridge cycling rates observed as variable shortening velocities and ATP consumption rates. The special properties of smooth muscle are associated with differences in the physiological roles of muscle in the walls of hollow organs and reflect a common molecular motor governed by different regulatory mechanisms. A remarkably simple scheme involving Ca(2+)-dependent phosphorylation of crossbridges in smooth muscle can predict much of the mechanical and energetics behavior characterizing the muscle of hollow organs. Nevertheless, many unresolved issues are identified that are the focus of current research efforts.

Animals↗
PubMed1992

Halothane and isoflurane effects on Ca2+ fluxes of isolated myocardial sarcoplasmic reticulum.

To elucidate better the differential myocardial depressant actions of halogenated volatile anesthetics, anesthetic-induced changes in Ca2+ accumulation, release, and Ca-ATPase (Ca2+ pump) activity of isolated canine cardiac sarcoplasmic reticulum (SR) vesicles were examined. An initial crude microsomal fraction of homogenized canine ventricle was subfractionated on a discontinuous sucrose gradient after Ca2+ loading in the presence of phosphate. Junctional SR (JSR) enriched with terminal cisternae was identified by its content of an electrophoretically verified approximately 450-kDa protein, the Ca(2+)-release channel (CaRC). When the CaRC of JSR was blocked by 1 microM ruthenium red (RR), the rate of Ca2+ uptake increased 47% as measured spectrophotometrically using the Ca-sensitive dye antipyrylazo III. A second fraction was identified as primarily longitudinal SR (LSR) based on its trace content of 450-kDa protein and 11% increase of Ca2+ uptake with RR. Halothane (0.75-2.5%) or isoflurane (2.5-4%) decreased net Ca2+ accumulation rate by either LSR or JSR, and the decrease in uptake rate of JSR was only partially reversed by addition of 1 microM RR (27% increase for isoflurane, 7% increase for halothane). Both halothane and isoflurane increased JSR ATP consumption as measured by a coupled-enzyme assay. 45Ca2+ efflux from passively loaded SR vesicles was then determined to verify that the decreased net uptake rate was due to enhanced Ca2+ efflux from vesicles. Both anesthetics increased passive Ca2+ efflux from SR vesicles in which the CaRC was blocked by 10 microM RR as well as those in which Ca2+ release via the CaRC was activated by 10 microM Ca2+.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2004

Comparative proteome analysis of Mycobacterium tuberculosis grown under aerobic and anaerobic conditions.

Data are presented from two-dimensional (2-D) PAGE analysis of Mycobacterium tuberculosis strain Harlingen grown during aerobic and anaerobic culture, according to a modified Wayne dormancy model. M. tuberculosis cultures were grown to the transition point between exponential growth and stationary phase in the presence of oxygen (7 days) and then part of the cultures was shifted to anaerobic conditions for 16 days. Growth declined similarly during aerobic and anaerobic conditions, whereas the ATP consumption rapidly decreased in the anaerobic cultures. 2-D PAGE revealed 50 protein spots that were either unique to, or more abundant during, anaerobic conditions and 16 of these were identified by MALDI-TOF. These proteins were the alpha-crystalline homologue (HspX), elongation factor Tu (Tuf), GroEL2, succinyl-CoA : 3-oxoacid-CoA transferase (ScoB), mycolic acid synthase (CmaA2), thioredoxin (TrxB2), beta-ketoacyl-ACP synthase (KasB), l-alanine dehydrogenase (Ald), Rv2005c, Rv2629, Rv0560c, Rv2185c and Rv3866. Some protein spots were found to be proteolytic fragments, e.g. HspX and GroEL2. These data suggest that M. tuberculosis induces expression of about 1 % of its genes in response to dormancy.

3-Oxoacyl-(Acyl-Carrier-Protein) Synthase↗
PubMed2006

Anticholinesterase toxicity and oxidative stress.

Anticholinesterase compounds, organophosphates (OPs) and carbamates (CMs) are commonly used for a variety of purposes in agriculture and in human and veterinary medicine. They exert their toxicity in mammalian system primarily by virtue of acetylcholinesterase (AChE) inhibition at the synapses and neuromuscular junctions, leading into the signs of hypercholinergic preponderance. However, the mechanism(s) involved in brain/muscle damage appear to be linked with alteration in antioxidant and the scavenging system leading to free radical-mediated injury. OPs and CMs cause excessive formation of F2-isoprostanes and F4-neuroprostanes, in vivo biomarkers of lipid peroxidation and generation of reactive oxygen species (ROS), and of citrulline, a marker of NO/NOS and reactive nitrogen species (RNS) generation. In addition, during the course of these excitatory processes and inhibition of AChE, a high rate of ATP consumption, coupled with the inhibition of oxidative phosphorylation, compromise the cell's ability to maintain its energy levels and excessive amounts of ROS and RNS may be generated. Pretreatment with N-methyl D-aspartate (NMDA) receptor antagonist memantine, in combination with atropine sulfate, provides significant protection against inhibition of AChE, increases of ROS/RNS, and depletion of high-energy phosphates induced by DFP/carbofuran. Similar antioxidative effects are observed with a spin trapping agent, phenyl-N-tert-butylnitrone (PBN) or chain breaking antioxidant vitamin E. This review describes the mechanisms involved in anticholinesterase-induced oxidative/nitrosative injury in target organs of OPs/CMs, and protection by various agents.

Animals↗
PubMed1998

Comparison of the inhibitory effect of sorbic acid and amphotericin B on Saccharomyces cerevisiae: is growth inhibition dependent on reduced intracellular pH?

The effects of sorbic acid and amphotericin B on the growth and intracellular pH (pHi) of Saccharomyces cerevisiae were studied and compared. Past evidence has suggested that the inhibitory action of sorbic acid on yeast is due to reduction of pHi per se. However, using a novel method to measure pHi in growing cells, little correlation was found between reduced growth rate on exposure to sorbic acid and reduction of pHi. In fact, growth inhibition correlated with an increase in the intracellular ADP/ATP ratio due to increased ATP consumption by the cells. This was partly attributed to the activation of protective mechanisms, such as increased proton pumping by the membrane H(+)-ATPase, which ensured that pHi did not decline when cells were exposed to sorbic acid. Therefore, the available evidence suggested that the inhibitory action of sorbic acid was due to the induction of an energetically expensive protective mechanism that compensated for any disruption of pHi homeostasis but resulted in less available energy for normal growth. In contrast to sorbic acid, with amphotericin B there was a direct correlation between growth inhibition and reduction of pHi due to the uncoupling effect of this compound on the plasma membrane. The inhibitory effect of amphotericin B was consistent with membrane disruption, or 'proton-uncoupling' leading to growth inhibition due to proton influx, decline in pHi and partial dissipation of the proton gradient.

Adenosine Diphosphate↗
PubMed2004

Functional consequences of single:double ring transitions in chaperonins: life in the cold.

The cpn60 and cpn10 genes from psychrophilic bacterium, Oleispira antarctica RB8, showed a positive effect in Escherichia coli growth at low temperature, shifting its theoretical minimal growth temperature from +7.5 degrees C to -13.7 degrees C [Ferrer, M., Chernikova, T.N., Yakimov, M., Golyshin, P.N., and Timmis, K.N. (2003) Nature Biotechnol 21: 1266-1267]. To provide experimental support for this finding, Cpn60 and 10 were overproduced in E. coli and purified to apparent homogeneity. Recombinant O.Cpn60 was identical to the native protein based on tetradecameric structure, and it dissociates during native PAGE. Gel filtration and native PAGE revealed that, in vivo and in vitro, (O.Cpn60)(7) was the active oligomer at 4-10 degrees C, whereas at > 10 degrees C, this complex was converted to (O.Cpn60)(14). The dissociation reduces the ATP consumption (energy-saving mechanism) and increases the refolding capacity at low temperatures. In order for this transition to occur, we demonstrated that K468 and S471 may play a key role in conforming the more advantageous oligomeric state in O.Cpn60. We have proved this hypothesis by showing that single and double mutations in K468 and S471 for T and G, as in E.GroEL, produced a more stable double-ring oligomer. The optimum temperature for ATPase and chaperone activity for the wild-type chaperonin was 24-28 degrees C and 4-18 degrees C, whereas that for the mutants was 45-55 degrees C and 14-36 degrees C respectively. The temperature inducing unfolding (T(M)) increased from 45 degrees C to more than 65 degrees C. In contrast, a single ring mutant, O.Cpn60(SR), with three amino acid substitutions (E461A, S463A and V464A) was as stable as the wild type but possessed refolding activity below 10 degrees C. Above 10 degrees C, this complex lost refolding capacity to the detriment of the double ring, which was not an efficient chaperone at 4 degrees C as the single ring variant. We demonstrated that expression of O.Cpn60(WT) and O.Cpn60(SR) leads to a higher growth of E. coli at 4 degrees C ( micro (max), 0.22 and 0.36 h(-1) respectively), whereas at 10-15 degrees C, only E. coli cells expressing O.Cpn60 or O.Cpn60(DR) grew better than parental cells (-cpn). These results clearly indicate that the single-to-double ring transition in Oleispira chaperonin is a wild-type mechanism for its thermal acclimation. Although previous studies have also reported single-to-double ring transitions under many circumstances, this is the first clear indication that single-ring chaperonins are necessary to support growth when the temperature falls from 37 degrees C to 4 degrees C.

Antarctic Regions↗
PubMed2005

Poly(ADP-ribose) polymerase in plants affects energy homeostasis, cell death and stress tolerance.

Plants contain two genes that code for poly(ADP-ribose) polymerase (PARP): parp1 and parp2. Both PARPs are activated by DNA damage caused by, example reactive oxygen species. Upon activation polymers of ADP-ribose are synthesized on a range of nuclear enzymes using NAD(+) as substrate. Here, we show that in plants stresses such as drought, high light and heat activate PARP causing NAD(+) breakdown and ATP consumption. When the PARP activity is reduced by means of chemical inhibitors or by gene silencing, cell death is inhibited and plants become tolerant to a broad range of abiotic stresses like high light, drought and heat. Plant lines with low poly(ADP-ribosyl)ation activity maintain under stress conditions their energy homeostasis by reducing NAD(+) breakdown and consequently energy consumption. The higher energy-use efficiency avoids the need for a too intense mitochondrial respiration and consequently reduces the formation of reactive oxygen species. From these results it can be concluded that breeding or engineering for a high energy-use efficiency under stress conditions is a valuable, but until today nearly unexploited, approach to enhance overall stress tolerance of crops.

Arabidopsis↗