GDH3 encodes a glutamate dehydrogenase isozyme, a previously unrecognized route for glutamate biosynthesis in Saccharomyces cerevisiae

Avendaño, Amaranta; DeLuna, Alexander; Olivera, Hiram; Valenzuela, Lourdes; González, Alicia

doi:10.1128/jb.179.17.5594-5597.1997

Cited by 84 publications

(89 citation statements)

References 26 publications

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“…cerevisiae is the first microorganism described in which the NADP-GDH activity is encoded by two genes (6); the physiological significance of this apparent redundancy is not clear. When this yeast is grown on glucose and ammonium as carbon and nitrogen sources, Gdh1p is the primary pathway for glutamate biosynthesis (6,9,10).…”

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confidence: 99%

“…The other pathway is mediated by the NADP ϩ -dependent glutamate dehydrogenase (NADP-GDH) 1 (EC 1.4.1.4), a broadly distributed enzyme that catalyzes the reductive amination of ␣-ketoglutarate to form glutamate (4,5). In S. cerevisiae, two genes (GDH1 and GDH3) have been described whose products constitute NADP-GDH isoenzymes (6). Glutamate catabolism is achieved through a reaction catalyzed by a different but related enzyme, the GDH2-encoded NAD ϩ -dependent glutamate dehydrogenase (NAD-GDH) (EC 1.4.1.2), which determines glutamate degradation to ammonium and ␣-ketoglutarate (4,7,8).…”

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confidence: 99%

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NADP-Glutamate Dehydrogenase Isoenzymes of Saccharomyces cerevisiae

DeLuna¹,

Avendaño

Riego

et al. 2001

Journal of Biological Chemistry

140

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In the yeast Saccharomyces cerevisiae, two NADP؉ -dependent glutamate dehydrogenases (NADP-GDHs) encoded by GDH1 and GDH3 catalyze the synthesis of glutamate from ammonium and ␣-ketoglutarate. The GDH2-encoded NAD ؉ -dependent glutamate dehydrogenase degrades glutamate producing ammonium and ␣-ketoglutarate. Until very recently, it was considered that only one biosynthetic NADP-GDH was present in S. cerevisiae. This fact hindered understanding the physiological role of each isoenzyme and the mechanisms involved in ␣-ketoglutarate channeling for glutamate biosynthesis. In this study, we purified and characterized the GDH1-and GDH3-encoded NADP-GDHs; they showed different allosteric properties and rates of ␣-ketoglutarate utilization. Analysis of the relative levels of these proteins revealed that the expression of GDH1 and GDH3 is differentially regulated and depends on the nature of the carbon source. Moreover, the physiological study of mutants lacking or overexpressing GDH1 or GDH3 suggested that these genes play nonredundant physiological roles. Our results indicate that the coordinated regulation of GDH1-, GDH3-, and GDH2-encoded enzymes results in glutamate biosynthesis and balanced utilization of ␣-ketoglutarate under fermentative and respiratory conditions. The possible relevance of the duplicated NADP-GDH pathway in the adaptation to facultative metabolism is discussed.

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confidence: 99%

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confidence: 99%

NADP-Glutamate Dehydrogenase Isoenzymes of Saccharomyces cerevisiae

DeLuna¹,

Avendaño

Riego

et al. 2001

Journal of Biological Chemistry

140

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“…Under conditions of limited ammonia, or in the absence of NADP-glutamate dehydrogenase, the glutamine synthetase (GS)-glutamate synthase (GOGAT) pathway functions to produce glutamate (Avendano et al, 1997). S. cerevisiae is unique in that it has two isozymes of NADP-glutamate dehydrogenase, GDH1 and GDH3, which are expressed in glucose and ethanol, respectively (Moye et al, 1985;Avendano et al, 1997).…”

Section: Discussionmentioning

confidence: 99%

“…encode major and minor isozymes of NADP-glutamate dehydrogenase, respectively (Moye et al, 1985;Avendano et al, 1997). To assess the effect of Mrg19p on the expression of these enzymes, we first compared GDH1 and GDH3 promoter activities in the MRG19 disruptant versus the wild-type strain when cells were grown in glycerol plus lactate as the carbon source under nitrogen-sufficient conditions.…”

Section: Expression Of Gdh1 and Gdh3 Is Dependent On Mrg19mentioning

confidence: 99%

Disruption of MRG19 results in altered nitrogen metabolic status and defective pseudohyphal development in Saccharomyces cerevisiae

Das

Bhat

2005

Microbiology

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It was previously shown that MRG19 downregulates carbon metabolism in Saccharomyces cerevisiae upon glucose exhaustion, and that the gene is glucose repressed. Here, it is shown that glucose repression of MRG19 is overcome upon nitrogen withdrawal, suggesting that MRG19 is a regulator of carbon and nitrogen metabolism. b-Galactosidase activity fostered by the promoter of GDH1/3, which encode anabolic enzymes of nitrogen metabolism, was altered in an MRG19 disruptant. As compared to the wild-type strain, the MRG19 disruptant showed a decrease in the ratio of 2-oxoglutarate to glutamate under nitrogen-limited conditions. MRG19 disruptants showed reduced pseudohyphal formation and enhanced sporulation, a phenomenon that occurs under conditions of both nitrogen and carbon withdrawal. These studies revealed that MRG19 regulates carbon and nitrogen metabolism, as well as morphogenetic changes, suggesting that MRG19 is a component of the link between the metabolic status of the cell and the corresponding developmental pathway. INTRODUCTIONMicro-organisms are endowed with the genetic capability to respond to frequently changing carbon and/or nitrogen deprivation by undergoing unique developmental changes. In Saccharomyces cerevisiae, deprivation of carbon and/or nitrogen elicits changes in metabolism and development to circumvent the nutritional deprivation (Esposito & Klapholz, 1981;Werner-Washburne et al., 1996;Gancedo, 2001). Diploid cells of S. cerevisiae undergo sporulation when carbon and nitrogen supply is limited (Esposito & Klapholz, 1981), whereas they put forth pseudohyphae in the absence of nitrogen but in the presence of glucose (Lorenz et al., 2000). These developmental changes, which are due to a combination of signals occurring in response to carbon and nitrogen withdrawal, indicate that the regulation of carbon and nitrogen metabolism is in some way interconnected. GLN3 responds to the low-nitrogen signal, and activates the transcription of nitrogen cataboliterepressed genes (Cunningham et al., 1996); mutation in this gene leads to an inability to put forth pseudohyphae (Lorenz & Heitman, 1998a, b). Recently, it was shown that GLN3 is also regulated by the glucose-responsive SNF1-kinase-mediated phosphorylation mechanism (Bertram et al., 2002;Cox et al., 2002); thus, it is evident that the regulation of carbon and nitrogen metabolism is interdependent. While it is clear that a unique collection of metabolic signals are required to induce specific morphogenetic changes, the underlying metabolic basis that predisposes the cell to opt for one or the other developmental programme is not clear.MRG19 was isolated as a multi-copy repressor of galactose toxicity (Kabir et al., 2000). It was observed that disruption of MRG19 resulted in the derepression of CYC1 under conditions of carbon limitation (Khanday et al., 2002). Based on this, it was suggested that in a wild-type strain, the function of MRG19 is to regulate the oxidation of limited carbon so as to channel it for biosynthesis. The protein is localized i...

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“…The divergent results for silencing for GDH1 and GDH3 upon first consideration might be surprising, as the two are paralogs (33), with the two proteins more than 90% similar in amino acid sequence. However, the genes are differentially regulated by carbon sources: Gdh1 is expressed and active in medium containing either glucose or ethanol, whereas Gdh3 is only detectable and active with ethanol as a carbon source (34).…”

Section: A Screen Revealed Diverse Amino Acid Metabolic Enzymes Withmentioning

confidence: 99%

Functions for diverse metabolic activities in heterochromatin

Xue

Pillus

2016

Proc. Natl. Acad. Sci. U.S.A.

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Growing evidence demonstrates that metabolism and chromatin dynamics are not separate processes but that they functionally intersect in many ways. For example, the lysine biosynthetic enzyme homocitrate synthase was recently shown to have unexpected functions in DNA damage repair, raising the question of whether other amino acid metabolic enzymes participate in chromatin regulation. Using an in silico screen combined with reporter assays, we discovered that a diverse range of metabolic enzymes function in heterochromatin regulation. Extended analysis of the glutamate dehydrogenase 1 (Gdh1) revealed that it regulates silent information regulator complex recruitment to telomeres and ribosomal DNA. Enhanced N-terminal histone H3 proteolysis is observed in GDH1 mutants, consistent with telomeric silencing defects. A conserved catalytic Asp residue is required for Gdh1's functions in telomeric silencing and H3 clipping. Genetic modulation of α-ketoglutarate levels demonstrates a key regulatory role for this metabolite in telomeric silencing. The metabolic activity of glutamate dehydrogenase thus has important and previously unsuspected roles in regulating chromatin-related processes.I n eukaryotic nuclei, DNA is wrapped around histones to form nucleosomes, the basic subunits of chromatin (1). The physical and chemical properties of chromatin are regulated by at least two types of enzymatic activities: chromatin remodeling and posttranslational modifications of histones and chromatin-associated proteins (2, 3). These enzymatic activities directly determine the accessibility of DNA for transcription, replication, and repair.In Saccharomyces cerevisiae, three genomic regions are known to contain loci repressed by chromatin-related activities. These include the HM silent mating-type loci (HMR and HML), regions within the ribosomal DNA (rDNA), and some telomeres. Transcriptional silencing at these loci is established and maintained by a number of factors, including the Sirtuin class III deacetylase activity of silent information protein 2 (Sir2). Notably, Sir2 uses NAD + as a cofactor to deacetylate histones H3 and H4 in newly deposited nucleosomes. Other than Sir2, the composition of the silencing complexes and the mechanisms of silencing are different for the three silenced regions, with the telomeres and the HM loci more similar to each other and the rDNA locus having distinct features (reviewed in ref. 4). Silencing at telomeres and the HM loci was long considered to follow a sequential model: initial deacetylation by Sir2 creates binding sites for Sir3 and Sir4, which in turn regulate the spreading of Sir2 across these regions (5). More recent high-resolution studies report a less uniform landscape for silenced chromatin (6), although the central importance of the Sir proteins remains clear. They, together with transcription factors including Rap1 and Abf1, form a multisubunit silencing complex known as the silent information regulator (SIR) complex. Silencing at the rDNA locus does not involve the SIR complex but ra...

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GDH3 encodes a glutamate dehydrogenase isozyme, a previously unrecognized route for glutamate biosynthesis in Saccharomyces cerevisiae

Cited by 84 publications

References 26 publications

NADP-Glutamate Dehydrogenase Isoenzymes of Saccharomyces cerevisiae

NADP-Glutamate Dehydrogenase Isoenzymes of Saccharomyces cerevisiae

Disruption of MRG19 results in altered nitrogen metabolic status and defective pseudohyphal development in Saccharomyces cerevisiae

Functions for diverse metabolic activities in heterochromatin

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