Teleological role of L-2-hydroxyglutarate dehydrogenase in the kidney

ABSTRACTL-2-hydroxyglutarate (L-2HG) is an oncometabolite found elevated in renal tumors. However, this molecule might have physiological roles that extend beyond its association with cancer, as L-2HG levels are elevated in response to hypoxia and during Drosophila larval development. L-2HG is known to be metabolized by L-2HG dehydrogenase (L2HGDH), and loss of L2HGDH leads to elevated L-2HG levels. Despite L2HGDH being highly expressed in the kidney, its role in renal metabolism has not been explored. Here, we report our findings utilizing a novel CRISPR/Cas9 murine knockout model, with a specific focus on the role of L2HGDH in the kidney. Histologically, L2hgdh knockout kidneys have no demonstrable histologic abnormalities. However, GC-MS metabolomics demonstrates significantly reduced levels of the TCA cycle intermediate succinate in multiple tissues. Isotope labeling studies with [U-13C] glucose demonstrate that restoration of L2HGDH in renal cancer cells (which lowers L-2HG) leads to enhanced incorporation of label into TCA cycle intermediates. Subsequent biochemical studies demonstrate that L-2HG can inhibit the TCA cycle enzyme α-ketoglutarate dehydrogenase. Bioinformatic analysis of mRNA expression data from renal tumors demonstrates that L2HGDH is co-expressed with genes encoding TCA cycle enzymes as well as the gene encoding the transcription factor PGC-1α, which is known to regulate mitochondrial metabolism. Restoration of PGC-1α in renal tumor cells results in increased L2HGDH expression with a concomitant reduction in L-2HG levels. Collectively, our analyses provide new insight into the physiological role of L2HGDH as well as mechanisms that promote L-2HG accumulation in disease states.

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The NAD Kinase Slr0400 Functions as a Growth Repressor in Synechocystis sp. PCC 6803

Plant and Cell Physiology ◽

10.1093/pcp/pcab023 ◽

2021 ◽

Author(s):

Yuuma Ishikawa ◽

Cedric Cassan ◽

Aikeranmu Kadeer ◽

Koki Yuasa ◽

Nozomu Sato ◽

...

Keyword(s):

Constitutive Expression ◽

Physiological Role ◽

Tca Cycle ◽

Growth Conditions ◽

Deficient Mutant ◽

Nad Kinase ◽

Cellular Processes ◽

The Tca Cycle ◽

Living Organisms

Abstract NADP+, the phosphorylated form of nicotinamide adenine dinucleotide (NAD), plays an essential role in many cellular processes. NAD kinase (NADK), which is conserved in all living organisms, catalyzes the phosphorylation of NAD+ to NADP+. However, the physiological role of phosphorylation of NAD+ to NADP+ in the cyanobacterium Synechocystis remains unclear. In this study, we report that slr0400, an NADK-encoding gene in Synechocystis, functions as a growth repressor under light-activated heterotrophic growth conditions and light and dark cycle conditions in the presence of glucose. We show, via characterization of NAD(P)(H) content and enzyme activity, that NAD+ accumulation in slr0400-deficient mutant results in the unsuppressed activity of glycolysis and tricarboxylic acid (TCA) cycle enzymes. In determining whether Slr0400 functions as a typical NADK, we found that constitutive expression of slr0400 in an Arabidopsis nadk2-mutant background complements the pale-green phenotype. Moreover, to determine the physiological background behind the growth advantage of mutants lacking slr04000, we investigated the photobleaching phenotype of slr0400-deficient mutant under high-light conditions. Photosynthetic analysis found in the slr0400-deficient mutant resulted from malfunctions in the Photosystem II (PSII) photosynthetic machinery. Overall, our results suggest that NADP(H)/NAD(H) maintenance by slr0400 plays a significant role in modulating glycolysis and the TCA cycle to repress the growth rate and maintain the photosynthetic capacity.

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Liquid-liquid extraction of succinate using a dicopper cryptate

10.26434/chemrxiv.11786784 ◽

2020 ◽

Author(s):

Riccardo Mobili ◽

Sonia La Cognata ◽

Francesca Merlo ◽

Andrea Speltini ◽

Massimo Boiocchi ◽

...

Keyword(s):

Aqueous Phase ◽

Visible Spectrum ◽

Tca Cycle ◽

Residual Concentration ◽

Waste Products ◽

Liquid Liquid Extraction ◽

The Tca Cycle ◽

Quantitative Extraction ◽

Uv Visible

<div> <p>The extraction of the succinate dianion from a neutral aqueous solution into dichloromethane is obtained using a lipophilic cage-like dicopper(II) complex as the extractant. The quantitative extraction exploits the high affinity of the succinate anion for the cavity of the azacryptate. The anion is effectively transferred from the aqueous phase, buffered at pH 7 with HEPES, into dichloromethane. A 1:1 extractant:anion adduct is obtained. Extraction can be easily monitored by following changes in the UV-visible spectrum of the dicopper complex in dichloromethane, and by measuring the residual concentration of succinate in the aqueous phase by HPLC−UV. Considering i) the relevance of polycarboxylates in biochemistry, as e.g. normal intermediates of the TCA cycle, ii) the relevance of dicarboxylates in the environmental field, as e.g. waste products of industrial processes, and iii) the recently discovered role of succinate and other dicarboxylates in pathophysiological processes including cancer, our results open new perspectives for research in all contexts where selective recognition, trapping and extraction of polycarboxylates is required. </p> </div>

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l-Aspartate: An Essential Metabolite for Plant Growth and Stress Acclimation

Molecules ◽

10.3390/molecules26071887 ◽

2021 ◽

Vol 26 (7) ◽

pp. 1887

Author(s):

Mei Han ◽

Can Zhang ◽

Peter Suglo ◽

Shuyue Sun ◽

Mingyao Wang ◽

...

Keyword(s):

Plant Growth ◽

Physiological Role ◽

Tca Cycle ◽

Extensive Study ◽

Cell Compartments ◽

Stress Acclimation ◽

Whole Plant ◽

Glycolysis Pathway ◽

Acid Pathway

L-aspartate (Asp) serves as a central building block, in addition to being a constituent of proteins, for many metabolic processes in most organisms, such as biosynthesis of other amino acids, nucleotides, nicotinamide adenine dinucleotide (NAD), the tricarboxylic acid (TCA) cycle and glycolysis pathway intermediates, and hormones, which are vital for growth and defense. In animals and humans, lines of data have proved that Asp is indispensable for cell proliferation. However, in plants, despite the extensive study of the Asp family amino acid pathway, little attention has been paid to the function of Asp through the other numerous pathways. This review aims to elucidate the most important aspects of Asp in plants, from biosynthesis to catabolism and the role of Asp and its metabolic derivatives in response to changing environmental conditions. It considers the distribution of Asp in various cell compartments and the change of Asp level, and its significance in the whole plant under various stresses. Moreover, it provides evidence of the interconnection between Asp and phytohormones, which have prominent functions in plant growth, development, and defense. The updated information will help improve our understanding of the physiological role of Asp and Asp-borne metabolic fluxes, supporting the modular operation of these networks.

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Liquid-liquid extraction of succinate using a dicopper cryptate

10.26434/chemrxiv.11786784.v1 ◽

2020 ◽

Cited By ~ 1

Author(s):

Riccardo Mobili ◽

Sonia La Cognata ◽

Francesca Merlo ◽

Andrea Speltini ◽

Massimo Boiocchi ◽

...

Keyword(s):

Aqueous Phase ◽

Visible Spectrum ◽

Tca Cycle ◽

Residual Concentration ◽

Waste Products ◽

Liquid Liquid Extraction ◽

The Tca Cycle ◽

Quantitative Extraction ◽

Uv Visible

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Targeting Altered Energy Metabolism in Colorectal Cancer: Oncogenic Reprogramming, the Central Role of the TCA Cycle and Therapeutic Opportunities

Cancers ◽

10.3390/cancers12071731 ◽

2020 ◽

Vol 12 (7) ◽

pp. 1731 ◽

Cited By ~ 1

Author(s):

Carina Neitzel ◽

Philipp Demuth ◽

Simon Wittmann ◽

Jörg Fahrer

Keyword(s):

Colorectal Cancer ◽

Energy Metabolism ◽

Pyruvate Dehydrogenase ◽

Pyruvate Dehydrogenase Complex ◽

Tca Cycle ◽

Dietary Factors ◽

Pyruvate Dehydrogenase Kinase ◽

Driver Mutations ◽

The Tca Cycle

Colorectal cancer (CRC) is among the most frequent cancer entities worldwide. Multiple factors are causally associated with CRC development, such as genetic and epigenetic alterations, inflammatory bowel disease, lifestyle and dietary factors. During malignant transformation, the cellular energy metabolism is reprogrammed in order to promote cancer cell growth and proliferation. In this review, we first describe the main alterations of the energy metabolism found in CRC, revealing the critical impact of oncogenic signaling and driver mutations in key metabolic enzymes. Then, the central role of mitochondria and the tricarboxylic acid (TCA) cycle in this process is highlighted, also considering the metabolic crosstalk between tumor and stromal cells in the tumor microenvironment. The identified cancer-specific metabolic transformations provided new therapeutic targets for the development of small molecule inhibitors. Promising agents are in clinical trials and are directed against enzymes of the TCA cycle, including isocitrate dehydrogenase, pyruvate dehydrogenase kinase, pyruvate dehydrogenase complex (PDC) and α-ketoglutarate dehydrogenase (KGDH). Finally, we focus on the α-lipoic acid derivative CPI-613, an inhibitor of both PDC and KGDH, and delineate its anti-tumor effects for targeted therapy.

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Deletion of the rpoZ gene, encoding the ω subunit of RNA polymerase, results in pleiotropic surface-related phenotypes in Mycobacterium smegmatis

Microbiology ◽

10.1099/mic.0.28879-0 ◽

2006 ◽

Vol 152 (6) ◽

pp. 1741-1750 ◽

Cited By ~ 32

Author(s):

Renjith Mathew ◽

Raju Mukherjee ◽

Radhakrishnan Balachandar ◽

Dipankar Chatterji

Keyword(s):

Rna Polymerase ◽

Mycobacterium Smegmatis ◽

Biofilm Formation ◽

Physiological Role ◽

Wild Type ◽

Gene Encoding ◽

Biofilm Growth ◽

Mutant Bacterium ◽

Sliding Motility

The ω subunit, the smallest subunit of bacterial RNA polymerase, is known to be involved in maintaining the conformation of the β′ subunit and aiding its recruitment to the rest of the core enzyme assembly in Escherichia coli. It has recently been shown in Mycobacterium smegmatis, by creating a deletion mutation of the rpoZ gene encoding ω, that the physiological role of the ω subunit also includes providing physical protection to β′. Interestingly, the mutant had altered colony morphology. This paper demonstrates that the mutant mycobacterium has pleiotropic phenotypes including reduced sliding motility and defective biofilm formation. Analysis of the spatial arrangement of biofilms by electron microscopy suggests that the altered phenotype of the mutant arises from a deficiency in generation of extracellular matrix. Complementation of the mutant strain with a copy of the wild-type rpoZ gene integrated in the bacterial chromosome restored both sliding motility and biofilm formation to the wild-type state, unequivocally proving the role of ω in the characteristics observed for the mutant bacterium. Analysis of the cell wall composition demonstrated that the mutant bacterium had an identical glycopeptidolipid profile to the wild-type, but failed to synthesize the short-chain mycolic acids characteristic of biofilm growth in M. smegmatis.

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The Role of Nicotinamide Nucleotide Transhydrogenase in Regulating the TCA Cycle in Mitochondria♦

Journal of Biological Chemistry ◽

10.1074/jbc.p112.396796 ◽

2013 ◽

Vol 288 (18) ◽

pp. 12978-12978

Keyword(s):

Tca Cycle ◽

Nicotinamide Nucleotide Transhydrogenase ◽

The Tca Cycle

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Phosphoserine Phosphatase Is Required for Serine and One-Carbon Unit Synthesis in Hydrogenobacter thermophilus

Journal of Bacteriology ◽

10.1128/jb.00409-17 ◽

2017 ◽

Vol 199 (21) ◽

Cited By ~ 5

Author(s):

Keugtae Kim ◽

Yoko Chiba ◽

Azusa Kobayashi ◽

Hiroyuki Arai ◽

Masaharu Ishii

Keyword(s):

Physiological Role ◽

Tca Cycle ◽

Content Type ◽

Phosphoserine Phosphatase ◽

Genes Encoding ◽

Hydrogenobacter Thermophilus ◽

Glycine Cleavage ◽

Major Donor ◽

Serine Biosynthesis

ABSTRACT Hydrogenobacter thermophilus is an obligate chemolithoautotrophic bacterium of the phylum Aquificae and is capable of fixing carbon dioxide through the reductive tricarboxylic acid (TCA) cycle. The recent discovery of two novel-type phosphoserine phosphatases (PSPs) in H. thermophilus suggests the presence of a phosphorylated serine biosynthesis pathway; however, the physiological role of these novel-type metal-independent PSPs (iPSPs) in H. thermophilus has not been confirmed. In the present study, a mutant strain with a deletion of pspA, the catalytic subunit of iPSPs, was constructed and characterized. The generated mutant was a serine auxotroph, suggesting that the novel-type PSPs and phosphorylated serine synthesis pathway are essential for serine anabolism in H. thermophilus. As an autotrophic medium supplemented with glycine did not support the growth of the mutant, the reversible enzyme serine hydroxymethyltransferase does not appear to synthesize serine from glycine and may therefore generate glycine and 5,10-CH2-tetrahydrofolate (5,10-CH2-THF) from serine. This speculation is supported by the lack of glycine cleavage activity, which is needed to generate 5,10-CH2-THF, in H. thermophilus. Determining the mechanism of 5,10-CH2-THF synthesis is important for understanding the fundamental anabolic pathways of organisms, because 5,10-CH2-THF is a major one-carbon donor that is used for the synthesis of various essential compounds, including nucleic and amino acids. The findings from the present experiments using a pspA deletion mutant have confirmed the physiological role of iPSPs as serine producers and show that serine is a major donor of one-carbon units in H. thermophilus. IMPORTANCE Serine biosynthesis and catabolism pathways are intimately related to the metabolism of 5,10-CH2-THF, a one-carbon donor that is utilized for the biosynthesis of various essential compounds. For this reason, determining the mechanism of serine synthesis is important for understanding the fundamental anabolic pathways of microorganisms. In the present study, we experimentally confirmed that a novel phosphoserine phosphatase in the obligate chemolithoautotrophic bacterium Hydrogenobacter thermophilus is essential for serine biosynthesis. This finding indicates that serine is synthesized from an intermediate of gluconeogenesis in H. thermophilus. In addition, because glycine cleavage system activity and genes encoding an enzyme capable of producing 5,10-CH2-THF were not detected, serine appears to be the major one-carbon donor to tetrahydrofolate (THF) in H. thermophilus.

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Regulation of the acuF Gene, Encoding Phosphoenolpyruvate Carboxykinase in the Filamentous Fungus Aspergillus nidulans

Journal of Bacteriology ◽

10.1128/jb.184.1.183-190.2002 ◽

2002 ◽

Vol 184 (1) ◽

pp. 183-190 ◽

Cited By ~ 11

Author(s):

Michael J. Hynes ◽

Oliver W. Draht ◽

Meryl A. Davis

Keyword(s):

Carbon Source ◽

Aspergillus Nidulans ◽

Phosphoenolpyruvate Carboxykinase ◽

Carbon Sources ◽

Tca Cycle ◽

Northern Blotting ◽

Gene Encoding ◽

The Tca Cycle ◽

Key Enzyme ◽

Acetate Utilization

ABSTRACT Phosphoenolpyruvate carboxykinase (PEPCK) is a key enzyme required for gluconeogenesis when microorganisms grow on carbon sources metabolized via the tricarboxylic acid (TCA) cycle. Aspergillus nidulans acuF mutants isolated by their inability to use acetate as a carbon source specifically lack PEPCK. The acuF gene has been cloned and shown to encode a protein with high similarity to PEPCK from bacteria, plants, and fungi. The regulation of acuF expression has been studied by Northern blotting and by the construction of lacZ fusion reporters. Induction by acetate is abolished in mutants unable to metabolize acetate via the TCA cycle, and induction by amino acids metabolized via 2-oxoglutarate is lost in mutants unable to form 2-oxoglutarate. Induction by acetate and proline is not additive, consistent with a single mechanism of induction. Malate and succinate result in induction, and it is proposed that PEPCK is controlled by a novel mechanism of induction by a TCA cycle intermediate or derivative, thereby allowing gluconeogenesis to occur during growth on any carbon source metabolized via the TCA cycle. It has been shown that the facB gene, which mediates acetate induction of enzymes specifically required for acetate utilization, is not directly involved in PEPCK induction. This is in contrast to Saccharomyces cerevisiae, where Cat8p and Sip4p, homologs of FacB, regulate PEPCK as well as the expression of other genes necessary for growth on nonfermentable carbon sources in response to the carbon source present. This difference in the control of gluconeogenesis reflects the ability of A. nidulans and other filamentous fungi to use a wide variety of carbon sources in comparison with S. cerevisiae. The acuF gene was also found to be subject to activation by the CCAAT binding protein AnCF, a protein homologous to the S. cerevisiae Hap complex and the mammalian NFY complex.

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