501
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Matsui A, Ashihara H. Nicotinate riboside salvage in plants: presence of nicotinate riboside kinase in mungbean seedlings. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2008; 46:104-108. [PMID: 18042392 DOI: 10.1016/j.plaphy.2007.10.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2007] [Indexed: 05/25/2023]
Abstract
Salvage of nicotinate riboside for NAD synthesis was investigated in mungbean seedlings. Nicotinate riboside kinase activity was detected in extracts from cotyledons. Exogenously supplied [carboxyl-(14)C]nicotinate riboside was readily converted into pyridine nucleotides in cotyledons of mungbean seedlings. This conversion was also found in embryonic axes, but the rate was lower than in cotyledons. These results suggest that, in addition to the seven-component pyridine nucleotide cycle (PNC VII), an eight-component cycle (PNC VIII) involving nicotinate riboside kinase operates in plants.
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Affiliation(s)
- Ayu Matsui
- Department of Biological Sciences, Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo, Japan
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502
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Roux MM, Radeke MJ, Goel M, Mushegian A, Foltz KR. 2DE identification of proteins exhibiting turnover and phosphorylation dynamics during sea urchin egg activation. Dev Biol 2008; 313:630-47. [DOI: 10.1016/j.ydbio.2007.10.053] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2007] [Revised: 10/29/2007] [Accepted: 10/31/2007] [Indexed: 10/22/2022]
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503
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Barski OA, Tipparaju SM, Bhatnagar A. The aldo-keto reductase superfamily and its role in drug metabolism and detoxification. Drug Metab Rev 2008; 40:553-624. [PMID: 18949601 PMCID: PMC2663408 DOI: 10.1080/03602530802431439] [Citation(s) in RCA: 363] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The aldo-keto reductase (AKR) superfamily comprises enzymes that catalyze redox transformations involved in biosynthesis, intermediary metabolism, and detoxification. Substrates of AKRs include glucose, steroids, glycosylation end-products, lipid peroxidation products, and environmental pollutants. These proteins adopt a (beta/alpha)(8) barrel structural motif interrupted by a number of extraneous loops and helixes that vary between proteins and bring structural identity to individual families. The human AKR family differs from the rodent families. Due to their broad substrate specificity, AKRs play an important role in the phase II detoxification of a large number of pharmaceuticals, drugs, and xenobiotics.
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Affiliation(s)
- Oleg A Barski
- Division of Cardiology, Department of Medicine, Institute of Molecular Cardiology, University of Louisville, Louisville, Kentucky 40202, USA.
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504
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Abstract
The role of NAD(+) metabolism in health and disease is of increased interest as the use of niacin (nicotinic acid) has emerged as a major therapy for treatment of hyperlipidemias and with the recognition that nicotinamide can protect tissues and NAD(+) metabolism in a variety of disease states, including ischemia/reperfusion. In addition, a growing body of evidence supports the view that NAD(+) metabolism regulates important biological effects, including lifespan. NAD(+) exerts potent effects through the poly(ADP-ribose) polymerases, mono-ADP-ribosyltransferases, and the recently characterized sirtuin enzymes. These enzymes catalyze protein modifications, such as ADP-ribosylation and deacetylation, leading to changes in protein function. These enzymes regulate apoptosis, DNA repair, stress resistance, metabolism, and endocrine signaling, suggesting that these enzymes and/or NAD(+) metabolism could be targeted for therapeutic benefit. This review considers current knowledge of NAD(+) metabolism in humans and microbes, including new insights into mechanisms that regulate NAD(+) biosynthetic pathways, current use of nicotinamide and nicotinic acid as pharmacological agents, and opportunities for drug design that are directed at modulation of NAD(+) biosynthesis for treatment of human disorders and infections.
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Affiliation(s)
- Anthony A Sauve
- Department of Pharmacology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA.
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505
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Ralser M, Wamelink MM, Kowald A, Gerisch B, Heeren G, Struys EA, Klipp E, Jakobs C, Breitenbach M, Lehrach H, Krobitsch S. Dynamic rerouting of the carbohydrate flux is key to counteracting oxidative stress. J Biol 2007; 6:10. [PMID: 18154684 PMCID: PMC2373902 DOI: 10.1186/jbiol61] [Citation(s) in RCA: 406] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Revised: 08/07/2007] [Accepted: 10/12/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Eukaryotic cells have evolved various response mechanisms to counteract the deleterious consequences of oxidative stress. Among these processes, metabolic alterations seem to play an important role. RESULTS We recently discovered that yeast cells with reduced activity of the key glycolytic enzyme triosephosphate isomerase exhibit an increased resistance to the thiol-oxidizing reagent diamide. Here we show that this phenotype is conserved in Caenorhabditis elegans and that the underlying mechanism is based on a redirection of the metabolic flux from glycolysis to the pentose phosphate pathway, altering the redox equilibrium of the cytoplasmic NADP(H) pool. Remarkably, another key glycolytic enzyme, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), is known to be inactivated in response to various oxidant treatments, and we show that this provokes a similar redirection of the metabolic flux. CONCLUSION The naturally occurring inactivation of GAPDH functions as a metabolic switch for rerouting the carbohydrate flux to counteract oxidative stress. As a consequence, altering the homoeostasis of cytoplasmic metabolites is a fundamental mechanism for balancing the redox state of eukaryotic cells under stress conditions.
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Affiliation(s)
- Markus Ralser
- Max Planck Institute for Molecular Genetics, Ihnestrasse 73, 14195 Berlin, Germany.
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506
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Yang T, Chan NYK, Sauve AA. Syntheses of nicotinamide riboside and derivatives: effective agents for increasing nicotinamide adenine dinucleotide concentrations in mammalian cells. J Med Chem 2007; 50:6458-61. [PMID: 18052316 DOI: 10.1021/jm701001c] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
A new two-step methodology achieves stereoselective synthesis of beta-nicotinamide riboside and a series of related amide, ester, and acid nucleosides. Compounds were prepared through a triacetylated-nicotinate ester nucleoside, via coupling of either ethylnicotinate or phenylnicotinate with 1,2,3,5-tetra-O-acetyl-beta-D-ribofuranose. Nicotinamide riboside, nicotinic acid riboside, O-ethylnicotinate riboside, O-methylnicotinate riboside, and several N-alkyl derivatives increased NAD+ concentrations from 1.2-2.7-fold in several mammalian cell lines. These findings establish bioavailability and potent effects of these nucleosides in stimulating the increase of NAD+ concentrations in mammalian cells.
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Affiliation(s)
- Tianle Yang
- Department of Pharmacology, Weill Medical College of Cornell University, Manhattan, NY 10021, USA
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507
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Functional localization of two poly(ADP-ribose)-degrading enzymes to the mitochondrial matrix. Mol Cell Biol 2007; 28:814-24. [PMID: 17991898 DOI: 10.1128/mcb.01766-07] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recent discoveries of NAD-mediated regulatory processes in mitochondria have documented important roles of this compartmentalized nucleotide pool in addition to energy transduction. Moreover, mitochondria respond to excessive nuclear NAD consumption arising from DNA damage-induced poly-ADP-ribosylation because poly(ADP-ribose) (PAR) can trigger the release of apoptosis-inducing factor from the organelles. To functionally assess mitochondrial NAD metabolism, we overexpressed the catalytic domain of nuclear PAR polymerase 1 (PARP1) and targeted it to the matrix, which resulted in the constitutive presence of PAR within the organelles. As a result, stably transfected HEK293 cells exhibited a decrease in NAD content and typical features of respiratory deficiency. Remarkably, inhibiting PARP activity revealed PAR degradation within mitochondria. Two enzymes, PAR glycohydrolase (PARG) and ADP-ribosylhydrolase 3 (ARH3), are known to cleave PAR. Both full-length ARH3 and a PARG isoform, which arises from alternative splicing, localized to the mitochondrial matrix. This conclusion was based on the direct demonstration of their PAR-degrading activity within mitochondria of living cells. The visualization of catalytic activity establishes a new approach to identify submitochondrial localization of proteins involved in the metabolism of NAD derivatives. In addition, targeted PARP expression may serve as a compartment-specific "knock-down" of the NAD content which is readily detectable by PAR formation.
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508
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Tu BP, Mohler RE, Liu JC, Dombek KM, Young ET, Synovec RE, McKnight SL. Cyclic changes in metabolic state during the life of a yeast cell. Proc Natl Acad Sci U S A 2007; 104:16886-91. [PMID: 17940006 PMCID: PMC2040445 DOI: 10.1073/pnas.0708365104] [Citation(s) in RCA: 195] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Indexed: 11/18/2022] Open
Abstract
Budding yeast undergo robust oscillations in oxygen consumption during continuous growth in a nutrient-limited environment. Using liquid chromatography-mass spectrometry and comprehensive 2D gas chromatography-mass spectrometry-based metabolite profiling methods, we have determined that the intracellular concentrations of many metabolites change periodically as a function of these metabolic cycles. These results reveal the logic of cellular metabolism during different phases of the life of a yeast cell. They may further indicate that oscillation in the abundance of key metabolites might help control the temporal regulation of cellular processes and the establishment of a cycle. Such oscillations in metabolic state might occur during the course of other biological cycles.
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Affiliation(s)
- Benjamin P. Tu
- *Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9038; and
| | | | - Jessica C. Liu
- *Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9038; and
| | | | - Elton T. Young
- Biochemistry, University of Washington, Seattle, WA 98195
| | | | - Steven L. McKnight
- *Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9038; and
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509
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Pollak N, Niere M, Ziegler M. NAD kinase levels control the NADPH concentration in human cells. J Biol Chem 2007; 282:33562-33571. [PMID: 17855339 DOI: 10.1074/jbc.m704442200] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
NAD kinases (NADKs) are vital, as they generate the cellular NADP pool. As opposed to three compartment-specific isoforms in plants and yeast, only a single NADK has been identified in mammals whose cytoplasmic localization we established by immunocytochemistry. To understand the physiological roles of the human enzyme, we generated and analyzed cell lines stably deficient in or overexpressing NADK. Short hairpin RNA-mediated down-regulation led to similar (about 70%) decrease of both NADK expression, activity, and the NADPH concentration and was accompanied by increased sensitivity toward H(2)O(2). Overexpression of NADK resulted in a 4-5-fold increase in the NADPH, but not NADP(+), concentration, although the recombinant enzyme phosphorylated preferentially NAD(+). Surprisingly, NADK overexpression and the ensuing increase of the NADPH level only moderately enhanced protection against oxidant treatment. Apparently, to maintain the NADPH level for the regeneration of oxidative defense systems human cells depend primarily on NADP-dependent dehydrogenases (which re-reduce NADP(+)), rather than on a net increase of NADP. The stable shifts of the NADPH level in the generated cell lines were also accompanied by alterations in the expression of peroxiredoxin 5 and Nrf2. Because the basal oxygen radical level in the cell lines was only slightly changed, the redox state of NADP may be a major transmitter of oxidative stress.
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Affiliation(s)
- Nadine Pollak
- Department of Molecular Biology, University of Bergen, Thormøhlensgate 55, N-5008 Bergen, Norway
| | - Marc Niere
- Department of Molecular Biology, University of Bergen, Thormøhlensgate 55, N-5008 Bergen, Norway
| | - Mathias Ziegler
- Department of Molecular Biology, University of Bergen, Thormøhlensgate 55, N-5008 Bergen, Norway.
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