scholarly journals MCART1/SLC25A51 is required for mitochondrial NAD transport

2020 ◽  
Vol 6 (43) ◽  
pp. eabe5310 ◽  
Author(s):  
Nora Kory ◽  
Jelmi uit de Bos ◽  
Sanne van der Rijt ◽  
Nevena Jankovic ◽  
Miriam Güra ◽  
...  
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Redox Reactions ◽  
Tca Cycle ◽  
Substrate Oxidation ◽  
Tricarboxylic Acid ◽  
Isolated Mitochondria ◽  
Mitochondrial Transporter ◽  
Transport Chain ◽  
Complex I Activity

The nicotinamide adenine dinucleotide (NAD+/NADH) pair is a cofactor in redox reactions and is particularly critical in mitochondria as it connects substrate oxidation by the tricarboxylic acid (TCA) cycle to adenosine triphosphate generation by the electron transport chain (ETC) and oxidative phosphorylation. While a mitochondrial NAD+ transporter has been identified in yeast, how NAD enters mitochondria in metazoans is unknown. Here, we mine gene essentiality data from human cell lines to identify MCART1 (SLC25A51) as coessential with ETC components. MCART1-null cells have large decreases in TCA cycle flux, mitochondrial respiration, ETC complex I activity, and mitochondrial levels of NAD+ and NADH. Isolated mitochondria from cells lacking or overexpressing MCART1 have greatly decreased or increased NAD uptake in vitro, respectively. Moreover, MCART1 and NDT1, a yeast mitochondrial NAD+ transporter, can functionally complement for each other. Thus, we propose that MCART1 is the long sought mitochondrial transporter for NAD in human cells.

scholarly journals MCART1 is required for mitochondrial NAD transport

2020 ◽  
Author(s):  
Nora Kory ◽  
Jelmi uit de Bos ◽  
Sanne van der Rijt ◽  
Nevena Jankovic ◽  
Miriam Güra ◽  
...  
Keyword(s):  
Redox Reactions ◽  
Tca Cycle ◽  
Substrate Oxidation ◽  
Isolated Mitochondria ◽  
Mitochondrial Transporter ◽  
Transport Chain ◽  
Atp Generation ◽  
Higher Eukaryotes ◽  
Complex I Activity

AbstractThe nicotinamide adenine dinucleotide (NAD+/NADH) pair is a cofactor in redox reactions and is particularly critical in mitochondria as it connects substrate oxidation by the tricarboxylic acid (TCA) cycle to ATP generation by the electron transport chain (ETC) and oxidative phosphorylation. While a mitochondrial NAD+ transporter has been identified in yeast, how NAD enters mitochondria in higher eukaryotes is unknown. Here, we mine gene essentiality data from human cell lines to identify MCART1 (SLC25A51) as co-essential with ETC components. MCART1-null cells have large decreases in TCA cycle flux, mitochondrial respiration, ETC complex I activity, and mitochondrial levels of NAD+ and NADH. Isolated mitochondria from cells lacking or overexpressing MCART1 have greatly decreased or increased NAD uptake in vitro, respectively. Moreover, MCART1 and NDT1, a yeast mitochondrial NAD+ transporter, can functionally complement for each other. Thus, we propose that MCART1 is the long sought mitochondrial transporter for NAD in human cells.

Alterations of Hepatic Microsomal Drug Metabolism by Glucagon

1975 ◽  
Vol 53 (5) ◽  
pp. 873-879 ◽  
Author(s):  
Jacob V. Aranda ◽  
Kenneth W. Renton
Keyword(s):  
Substrate Oxidation ◽  
Type I ◽  
Nadph Cytochrome ◽  
Transport Chain ◽  
Hexobarbital Sleeping Time ◽  
Nadph Oxidation ◽  
In Vivo Effects ◽  
Cytochrome P 450

The effect of glucagon on the components of the hepatic microsomal electron transport chain (NADPH oxidase, NADPH cytochrome c reductase (EC 1.6.2.4), cytochrome P-450, and NADPH cytochrome P-450 reductase), and on two representative oxidative pathways (aminopyrine N-demethylation, a type I substrate oxidation; and aniline p-hydroxylation, a type II substrate oxidation) was determined. Microsomes from rats pretreated with glucagon (300 μg/kg per day for 3 days) showed a significant decrease in NADPH oxidation and in aminopyrine N-demethylation with a prolonged hexobarbital sleeping time, and a significant increase in aniline p-hydroxylation. Microsomes from rats pretreated with a lower dose of glucagon (30 μg/kg per day for 3 days) showed a significant decrease in the microsomal N-demethylation of aminopyrine. Glucagon had no effect when added in vitro to microsomes, suggesting that the in vivo effects of glucagon are mediated indirectly in the intact animal.

scholarly journals Succinate Dehydrogenase and Ribonucleic Acid Networks in Cancer and Other Diseases

Cancers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3237
Author(s):  
Cerena Moreno ◽  
Ruben Mercado Santos ◽  
Robert Burns ◽  
Wen Cai Zhang
Keyword(s):  
Succinate Dehydrogenase ◽  
Ribonucleic Acid ◽  
Tca Cycle ◽  
Tricarboxylic Acid ◽  
Signal Pathways ◽  
Mechanistic Studies ◽  
Network Interaction ◽  
Transport Chain ◽  
Sdh Mutation ◽  
Non Coding Rnas

Succinate dehydrogenase (SDH) complex connects both the tricarboxylic acid (TCA) cycle and the electron transport chain (ETC) in the mitochondria. However, SDH mutation or dysfunction-induced succinate accumulation results in multiple cancers and non-cancer diseases. The mechanistic studies show that succinate activates hypoxia response and other signal pathways via binding to 2-oxoglutarate-dependent oxygenases and succinate receptors. Recently, the increasing knowledge of ribonucleic acid (RNA) networks, including non-coding RNAs, RNA editors, and RNA modifiers has expanded our understanding of the interplay between SDH and RNA networks in cancer and other diseases. Here, we summarize recent discoveries in the RNA networks and their connections to SDH. Additionally, we discuss current therapeutics targeting SDH in both pre-clinical and clinical trials. Thus, we propose a new model of SDH–RNA network interaction and bring promising RNA therapeutics against SDH-relevant cancer and other diseases.

scholarly journals BNIP3 contributes to the glutamine-driven aggressive behavior of melanoma cells

2019 ◽  
Vol 400 (2) ◽  
pp. 187-193 ◽  
Author(s):  
Monica Vara-Perez ◽  
Hannelore Maes ◽  
Sarah Van Dingenen ◽  
Patrizia Agostinis
Keyword(s):  
Melanoma Cell ◽  
Warburg Effect ◽  
Aerobic Glycolysis ◽  
Tca Cycle ◽  
Melanoma Cells ◽  
Tricarboxylic Acid ◽  
Mediated Effects ◽  
Melanoma Cell Proliferation ◽  
Vital Component

AbstractAerobic glycolysis (‘Warburg effect’) is used by cancer cells to fuel tumor growth. Interestingly, metastatic melanoma cells rely on glutaminolysis rather than aerobic glycolysis for their bioenergetic needs through the tricarboxylic acid (TCA) cycle. Here, we compared the effects of glucose or glutamine on melanoma cell proliferation, migration and oxidative phosphorylationin vitro. We found that glutamine-driven melanoma cell’s aggressive traits positively correlated with increased expression of HIF1α and its pro-autophagic target BNIP3. BNIP3 silencing reduced glutamine-mediated effects on melanoma cell growth, migration and bioenergetics. Hence, BNIP3 is a vital component of the mitochondria quality control required for glutamine-driven melanoma aggressiveness.

Mitochondrial transporter responsiveness and metabolic flux homeostasis in postischemic hearts

1999 ◽  
Vol 277 (3) ◽  
pp. H866-H873 ◽  
Author(s):  
J. Michael O’Donnell ◽  
Lawrence T. White ◽  
E. Douglas Lewandowski
Keyword(s):  
Redox State ◽  
Metabolic Flux ◽  
Tca Cycle ◽  
Tricarboxylic Acid ◽  
Stunned Myocardium ◽  
Mitochondrial Transporter ◽  
Metabolite Exchange ◽  
Stimulation Of ◽  
Shuttle Response

The transport of metabolites between mitochondria and cytosol via the α-ketoglutarate-malate carrier serves to balance flux between the two spans of the tricarboxylic acid (TCA) cycle but is reduced in stunned myocardium. To examine the mechanism for reduced transporter activity, we followed the postischemic response of metabolite influx/efflux from mitochondria to stimulation of the malate-aspartate (MA) shuttle. Isolated rabbit hearts were either perfused with 2.5 mM [2-13C]acetate ( n = 7) or similarly reperfused ( n = 5) after 10-min ischemia. In other hearts, the MA shuttle was stimulated with a high cytosolic redox state (NADH) induced by 2.5 mM lactate in normal ( n = 6) or reperfused hearts ( n = 7). In normal hearts, the MA shuttle response accelerated transport from 8.3 ± 3.4 to 16.2 ± 5.0 μmol ⋅ min−1 ⋅ g dry wt−1. Although transport was reduced in stunned hearts, the MA shuttle was responsive to cytosolic NADH load, increasing transport from 3.4 ± 1.0 to 9.8 ± 3.7 μmol ⋅ min−1 ⋅ g dry wt−1. Therefore, metabolite exchange remains intact in stunned myocardium but responds to changes in TCA cycle flux regulation.

scholarly journals Thioredoxin, a master regulator of the tricarboxylic acid cycle in plant mitochondria

2015 ◽  
Vol 112 (11) ◽  
pp. E1392-E1400 ◽  
Author(s):  
Danilo M. Daloso ◽  
Karolin Müller ◽  
Toshihiro Obata ◽  
Alexandra Florian ◽  
Takayuki Tohge ◽  
...  
Keyword(s):  
Tricarboxylic Acid Cycle ◽  
Plant Mitochondria ◽  
Tca Cycle ◽  
Tricarboxylic Acid ◽  
Mitochondrial Enzymes ◽  
Atp Citrate Lyase ◽  
Cycle Enzyme ◽  
The Tca Cycle

Plant mitochondria have a fully operational tricarboxylic acid (TCA) cycle that plays a central role in generating ATP and providing carbon skeletons for a range of biosynthetic processes in both heterotrophic and photosynthetic tissues. The cycle enzyme-encoding genes have been well characterized in terms of transcriptional and effector-mediated regulation and have also been subjected to reverse genetic analysis. However, despite this wealth of attention, a central question remains unanswered: “What regulates flux through this pathway in vivo?” Previous proteomic experiments withArabidopsisdiscussed below have revealed that a number of mitochondrial enzymes, including members of the TCA cycle and affiliated pathways, harbor thioredoxin (TRX)-binding sites and are potentially redox-regulated. We have followed up on this possibility and found TRX to be a redox-sensitive mediator of TCA cycle flux. In this investigation, we first characterized, at the enzyme and metabolite levels, mutants of the mitochondrial TRX pathway inArabidopsis: theNADP-TRX reductasea and b double mutant (ntra ntrb) and the mitochondrially locatedthioredoxin o1(trxo1) mutant. These studies were followed by a comparative evaluation of the redistribution of isotopes when13C-glucose,13C-malate, or13C-pyruvate was provided as a substrate to leaves of mutant or WT plants. In a complementary approach, we evaluated the in vitro activities of a range of TCA cycle and associated enzymes under varying redox states. The combined dataset suggests that TRX may deactivate both mitochondrial succinate dehydrogenase and fumarase and activate the cytosolic ATP-citrate lyase in vivo, acting as a direct regulator of carbon flow through the TCA cycle and providing a mechanism for the coordination of cellular function.

scholarly journals Involvement of enzymes of amino acid metabolism and tricarboxylic acid cycle in bovine oocyte maturation in vitro

Reproduction ◽  
2003 ◽  
pp. 753-763 ◽  
Author(s):  
P Cetica ◽  
L Pintos ◽  
G Dalvit ◽  
M Beconi
Keyword(s):  
Amino Acid ◽  
Isocitrate Dehydrogenase ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Tricarboxylic Acid Cycle ◽  
Tca Cycle ◽  
Cumulus Cells ◽  
Tricarboxylic Acid ◽  
Maturation In Vitro

Few studies demonstrate at a biochemical level the metabolic profile of both cumulus cells and the oocyte during maturation. The aim of the present study was to investigate the differential participation of enzymatic activity in cumulus cells and in the oocyte during in vitro maturation (IVM) by studying the activity of enzymes involved in the control of amino acid metabolism, alanine aminotransferase (ALT) and aspartate aminotransferase (AST); and the tricarboxylic acid (TCA) cycle, isocitrate dehydrogenase (IDH) and malate dehydrogenase (MDH). No NAD-dependent isocitrate dehydrogenase (NAD-IDH) activity was recorded in cumulus-oocyte complexes (COCs). ALT, AST, NADP-dependent isocitrate dehydrogenase (NADP-IDH) and MDH enzymatic units remained constant in cumulus cells and oocytes during IVM. Specific activities increased in oocytes and decreased in cumulus cells as a result of IVM (P<0.05). Similar activity of both transaminases was detected in cumulus cells, unlike in the oocyte, in which activity of AST was 4.4 times greater than that of ALT (P<0.05). High NADP-IDH and MDH activity was detected in the oocyte. Addition of alanine, aspartate, isocitrate + NADP, oxaloacetate or malate + NAD to maturation media increased the percentage of denuded oocytes reaching maturation (P<0.05), in contrast to COCs in which differences were not observed by addition of these substrates and co-enzymes. The activity of studied enzymes and the use of oxidative substrates denotes a major participation of transaminations and the TCA cycle in the process of gamete maturation. The oocyte thus seems versatile in the use of several oxidative substrates depending on the redox state.

scholarly journals Development of a LC-MS/MS Method for the Simultaneous Detection of Tricarboxylic Acid Cycle Intermediates in a Range of Biological Matrices

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Omar Al Kadhi ◽  
Antonietta Melchini ◽  
Richard Mithen ◽  
Shikha Saha
Keyword(s):  
Ex Vivo ◽  
Tricarboxylic Acid Cycle ◽  
Simultaneous Detection ◽  
Tca Cycle ◽  
Tricarboxylic Acid ◽  
In Vivo Studies ◽  
Biological Matrices ◽  
Wide Range ◽  
Tca Cycle Intermediates

It is now well-established that perturbations in the tricarboxylic acid (TCA) cycle play an important role in the metabolic transformation occurring in cancer including that of the prostate. A method for simultaneous qualitative and quantitative analysis of TCA cycle intermediates in body fluids, tissues, and cultured cell lines of human origin was developed using a common C18 reversed-phase column by LC-MS/MS technique. This LC-MS/MS method for profiling TCA cycle intermediates offers significant advantages including simple and fast preparation of a wide range of human biological samples. The analytical method was validated according to the guideline of the Royal Society of Chemistry Analytical Methods Committee. The limits of detection were below 60 nM for most of the TCA intermediates with the exception of lactic and fumaric acids. The calibration curves of all TCA analytes showed linearity with correlation coefficientsr2>0.9998. Recoveries were >95% for all TCA analytes. This method was established taking into consideration problems and limitations of existing techniques. We envisage that its application to different biological matrices will facilitate deeper understanding of the metabolic changes in the TCA cycle from in vitro, ex vivo, and in vivo studies.

scholarly journals Asparagine signals mitochondrial respiration and can be targeted to impair tumour growth

2020 ◽  
Author(s):  
Abigail S. Krall ◽  
Peter J. Mullen ◽  
Felicia Surjono ◽  
Milica Momcilovic ◽  
Ernst W. Schmid ◽  
...  
Keyword(s):  
Mitochondrial Respiration ◽  
Electron Transport Chain ◽  
Tumour Growth ◽  
Therapeutic Strategy ◽  
Tca Cycle ◽  
Nucleotide Synthesis ◽  
Transport Chain ◽  
Mouse Models Of Cancer

AbstractMitochondrial respiration is critical for cell proliferation. In addition to producing ATP via the electron transport chain (ETC), respiration is required for the generation of TCA cycle-derived biosynthetic precursors, such as aspartate, an essential substrate for nucleotide synthesis. Because mTORC1 coordinates availability of biosynthetic precursors with anabolic metabolism, including nucleotide synthesis, a link between respiration and mTORC1 is fitting. Here we show that in addition to depleting intracellular aspartate, ETC inhibition depletes aspartate-derived asparagine and impairs mTORC1 activity. Providing exogenous asparagine restores mTORC1 activity, nucleotide synthesis, and proliferation in the context of ETC inhibition without restoring intracellular aspartate in a panel of cancer cell lines. As a therapeutic strategy, the combination of ETC inhibitor metformin, which limits tumour asparagine synthesis, and either asparaginase or dietary asparagine restriction, which limit tumour asparagine consumption, effectively impairs tumour growth in several mouse models of cancer. Because environmental asparagine is sufficient to restore proliferation with respiration impairment, both in vitro and in vivo, our findings suggest that asparagine synthesis is a fundamental purpose of mitochondrial respiration. Moreover, the results suggest that asparagine signals active respiration to mTORC1 to communicate biosynthetic precursor sufficiency and promote anabolism.

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