Differential synthesis of glyceraldehyde-3-phosphate dehydrogenase polypeptides in stressed yeast cells

Abstract Three unlinked genes, TDH1, TDH2 and TDH3 , encode the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (triose-phosphate dehydrogenase; TDK) in the yeast Saccharomyces cerevisiae . We demonstrate that the synthesis of the three encoded TDK polypeptides (TDHa, TDHb and TDHc, respectively) is not co-ordinately regulated and that TDHa is only synthesised as cells enter stationary phase, due to glucose starvation, or in heat-shocked cells. Furthermore, the synthesis of TDHb, but not TDHc, is strongly repressed by a heat shock. Hence, the TDHa enzyme may play a cellular role, distinct from glycolysis, that is required by stressed cells.     

The GCR1 gene encodes a positive transcriptional regulator of the enolase and glyceraldehyde-3-phosphate dehydrogenase gene families in Saccharomyces cerevisiae.

The intracellular concentrations of the polypeptides encoded by the two enolase (ENO1 and ENO2) and three glyceraldehyde-3-phosphate dehydrogenase (TDH1, TDH2, and TDH3) genes were coordinately reduced more than 20-fold in a Saccharomyces cerevisiae strain carrying the gcr1-1 mutation. The steady-state concentration of glyceraldehyde-3-phosphate dehydrogenase mRNA was shown to be approximately 50-fold reduced in the mutant strain. Overexpression of enolase and glyceraldehyde-3-phosphate dehydrogenase in strains carrying multiple copies of either ENO1 or TDH3 was reduced more than 50-fold in strains carrying the gcr1-1 mutation. These results demonstrated that the GCR1 gene encodes a trans-acting factor which is required for efficient and coordinate expression of these glycolytic gene families. The GCR1 gene and the gcr1-1 mutant allele were cloned and sequenced. GCR1 encodes a predicted 844-amino-acid polypeptide; the gcr1-1 allele contains a 1-base-pair insertion mutation at codon 304. A null mutant carrying a deletion of 90% of the GCR1 coding sequence and a URA3 gene insertion was constructed by gene replacement. The phenotype of a strain carrying this null mutation was identical to that of the gcr1-1 mutant strain.     

Isolation and characterization of yeast strains carrying mutations in the glyceraldehyde-3-phosphate dehydrogenase genes

Mutant yeast strains were constructed which carry insertion mutations in each of the glyceraldehyde-3-phosphate dehydrogenase structural genes which have been designated TDH1, TDH2, and TDH3. Haploid strains carrying mutations in TDH1 and TDH2 as well as TDH1 and TDH3 were isolated from crosses between strains carrying the appropriate single mutations. The three single mutants as well as the two double mutants grow at wild type rates when ethanol is used as carbon source. Mutant strains lacking only a functional TDH2 allele or a TDH3 allele grow at 50 and 75% of the rate observed for wild type cells, respectively, when glucose is used as carbon source. No growth phenotype was observed for strains lacking only a functional TDH1 allele when either fermentable or nonfermentable carbon sources were used. Evidence is presented that strains lacking functional TDH2 and TDH3 alleles are not viable. These data demonstrate that the presence of a functional TDH2 or TDH3 allele is required for cell growth.     

Targeted deletion of a yeast enolase structural gene. Identification and isolation of yeast enolase isozymes

Yeast contain two nontandemly repeated enolase structural genes which have been isolated on bacterial plasmids designated peno46 and peno8 (Holland, M. J., Holland, J. P., Thill, G. P., and Jackson, K. A. (1981) J. Biol. Chem. 256, 1385-1395). In order to study the expression of the enolase genes in vivo, the resident enolase gene in a wild type yeast strain corresponding to the gene isolated on peno46 was replaced with a deletion, constructed in vitro, which lacks 90% of the enolase coding sequences. Three catalytically active enolases are resolved differ DEAE-Sephadex chromatography of wild type cellular extracts. As expected, a single form of enolase was resolved from extracts of the mutant cell. Immunological and electrophoretic analyses of the multiple forms of enolase confirm that two enolase genes are expressed in wild type cells and that isozymes are formed in the cell by random assortment of the two polypeptides into three active enolase dimers. The yeast enolase loci have been designated ENO1 and ENO2. The deletion mutant lacks the enolase 1 polypeptide confirming that this polypeptide is encoded by the gene isolated on peno46. The intracellular steady state concentrations of the two polypeptides are dependent on the carbon source used to propagate the cells. Log phase cells grown on glucose contain 20-fold more enolase 2 polypeptide than enolase 1 polypeptide, whereas cells grown on ethanol or glycerol plus lactate contain similar amounts of the two polypeptides. The 20-fold higher than in cells grown on the nonfermentable carbon sources. In vitro translation of total cellular RNA suggests that the steady state concentrations of the two enolase mRNAs in cells grown on different carbon sources are proportional to the steady state concentrations of the respective enolase polypeptides.     

A Reduction in Age-Enhanced Gluconeogenesis Extends Lifespan

The regulation of energy metabolism, such as calorie restriction (CR), is a major determinant of cellular longevity. Although augmented gluconeogenesis is known to occur in aged yeast cells, the role of enhanced gluconeogenesis in aged cells remains undefined. Here, we show that age-enhanced gluconeogenesis is suppressed by the deletion of the tdh2 gene, which encodes glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a protein that is involved in both glycolysis and gluconeogenesis in yeast cells. The deletion of TDH2 restores the chronological lifespan of cells with deletions of both the HST3 and HST4 genes, which encode yeast sirtuins, and represses the activation of gluconeogenesis. Furthermore, the tdh2 gene deletion can extend the replicative lifespan in a CR pathway-dependent manner. These findings demonstrate that the repression of enhanced gluconeogenesis effectively extends the cellular lifespan.     

Isolation and characterization of a gene coding for glyceraldehyde-3-phosphate dehydrogenase from Saccharomyces cerevisiae.

A yeast glyceraldehyde-3-phosphate dehydrogenase gene has been isolated from a collection of Escherichia coli transformants containing randomly sheared segments of yeast genomic DNA. Complementary DNA, synthesized from partially purified glyceraldehyde-3-phosphate dehydrogenase messenger RNA, was used as a hybridization probe for cloning this gene. The isolated hybrid plasmid DNA has been mapped with restriction endonucleases and the location of the glyceraldehyde-3-phosphate dehydrogenase gene within the cloned segment of yeast DNA has been established. There are approximately 4.5 kilobase pairs of DNA sequence flanking either side of the glyceraldehyde-3-phosphate dehydrogenase gene in the cloned segment of yeast DNA. The isolated hybrid plasmid DNA has been used to selectively hybridize glyceraldehyde-3-phosphate dehydrogenase messenger RNA from unfractionated yeast poly(adenylic acid)-containing messenger RNA. The nucleotide sequence of a portion of the isolated hybrid plasmid DNA has been determined. This nucleotide sequence encodes 29 amino acids which are at the COOH terminus of the known amino acid sequence of yeast glyceraldehyde-3-phosphate dehydrogenase.     

Interaction of the GTS1 gene product with glyceraldehyde- 3-phosphate dehydrogenase 1 required for the maintenance of the metabolic oscillations of the yeast Saccharomyces cerevisiae.

We previously reported that GTS1 is involved in regulating ultradian oscillations of the glycolytic pathway induced by cyanide in cell suspensions as well as oscillations of energy metabolism in aerobic continuous cultures. Here, we screened a yeast cDNA library for proteins that bind to Gts1p using the yeast two-hybrid system and cloned multiple TDH cDNAs encoding the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). We found that the zinc-finger and dimerization sites of Gts1p were required for full ability to bind GAPDH, and Gts1ps mutated at these sites lost the ability to regulate both aerobic and unaerobic ultradian oscillations of energy metabolism. Of the three TDH genes, only TDH1 fluctuated at the mRNA level in continuous culture and its deletion resulted in the disappearance of the oscillation without any affect on growth rate. This loss of biological rhythms in the TDH1-deleted mutant was rescued by the expression of TDH1 but not of TDH2 or TDH3 under the control of the TDH1 promoter. Thus, we hypothesized that Gts1p plays a role in the regulation of metabolic oscillation by interacting with the TDH1 product, GAPDH1, in yeast.     

The yeast SSS1 gene is essential for secretory protein translocation and encodes a conserved protein of the endoplasmic reticulum.

The SEC61, SEC62 and SEC63 yeast gene products are membrane components of the apparatus that catalyses protein translocation into the endoplasmic reticulum (ER). In the hope of uncovering additional components of the translocation apparatus, we sought yeast genes whose overexpression would restore partial thermoresistance in a sec61 translocation-deficient mutant. The first extragenic Sec sixty-one suppressor, SSS1, is an essential single copy gene whose overexpression restores translocation in the sec61 mutant. Another extragenic suppressor was identified as TDH3, which encodes the major isozyme of the most abundant yeast protein, glyceraldehyde-3-phosphate dehydrogenase. TDH3 overexpression could exert an indirect effect by competitively inhibiting protein synthesis, thereby allowing the impaired translocation apparatus to cope with a reduced flow of newly synthesized secretory proteins. Depletion of the Sss1 protein rapidly results in accumulation of multiple secretory or membrane proteins devoid of post-translational modifications; the normally secreted alpha-factor accumulates on the cytosolic side of ER membranes. Thus, the SSS1 gene is required for continued translocation of secretory preproteins beyond their early association to ER membranes. Consistent with its essential role in protein translocation, the Sss1 protein localizes to the ER and homologues were detected in higher eukaryotes.     

Properties of two high-molecular-mass forms of glyceraldehyde-3-phosphate dehydrogenase from spinach leaf, one of which also possesses latent phosphoribulokinase activity.

Two high-Mr forms of chloroplast glyceraldehyde-3-phosphate dehydrogenase from spinach leaf can be separated by DEAE-cellulose chromatography. One form, the high-Mr glyceraldehyde-3-phosphate dehydrogenase, resembles an enzyme previously described [Yonuschot, G.R., Ortwerth, B.J. & Koeppe, O.J. (1970) J. Biol. Chem. 245, 4193-4198]. The other, a glyceraldehyde-3-phosphate dehydrogenase/phosphoribulokinase complex, is characterised by possession of latent phosphoribulokinase activity, only expressed following incubation with dithiothreitol. This complex is composed not only of subunits A (39.5 kDa) and B (41.5 kDa) characteristic of the high-Mr glyceraldehyde-3-phosphate dehydrogenase, but also of a third subunit, R (40.5 kDa) comigrating with that from the active phosphoribulokinase of spinach. Incubation of the complex with dithiothreitol markedly stimulated both its phosphoribulokinase and NADPH-dependent dehydrogenase activities. This dithiothreitol-induced activation was accompanied by depolymerisation to give two predominantly NADPH-linked tetrameric glyceraldehyde-3-phosphate dehydrogenases (the homotetramer, A4, and the heterotetramer, A2B2) as well as the active dimeric phosphoribulokinase. Incubation of the high-Mr glyceraldehyde-3-phosphate dehydrogenase with dithiothreitol promoted complete depolymerisation yielding only the heterotetramer (A2B2). Possible structures suggested for the glyceraldehyde-3-phosphate dehydrogenase/phosphoribulokinase complex are (A2B2)2A4R2 or (A2B2)(A4)2R2.     

Isolation and identification of yeast messenger ribonucleic acids coding for enolase, glyceraldehyde-3-phosphate dehydrogenase, and phosphoglycerate kinase.

Yeast poly(adenylic acid)-containing messenger ribonucleic acid isolated from two strains of Saccharomyces cerevisiae was fractionated by preparative polyacrylamide gel electrophoresis in the presence of formamide. Three messenger ribonucleic acids, present at high intracellular concentration, were electrophoretically eluted from the polyacrylamide gels and translated in a wheat germ cell-free extract. The in vitro synthesized polypeptides were identified by tryptic peptide analysis. Messenger ribonucleic acids coding for enolase and glyceraldehyde-3-phosphate dehydrogenase were isolated from commercially grown baker's yeast (strain F1), and messenger ribonucleic acid coding for phosphoglycerate kinase was isolated from Saccharomyces cerevisiae (ATCC 24657). Significant differences in the spectrum of abundant messenger ribonucleic acids isolated from commercially grown baker's yeast (strain F1) and strain 24657 were observed. When both strains were grown under identical conditions, however, the spectrum of messenger ribonucleic acid isolated from the cells is indistinguishable.     

The glyceraldehyde-3-phosphate dehydrogenase gene family in the nematode, Caenorhabditis elegans: isolation and characterization of one of the genes

The isolation and genomic sequence of one of possibly four glyceraldehyde-3-phosphate dehydrogenase genes in the nematode, Caenorhabditis elegans is presented. The complete nucleotide sequence of the coding as well as the noncoding flanking regions of this gene has been determined. The deduced amino-acid sequence agrees with the sequence of typical glyceraldehyde-3-phosphate dehydrogenase enzymes and its molecular weight of 36,235 agrees with its size determined previously (Yarbrough, P. and Hecht, R. (1984) J. Biol. Chem. 259, 14711-14720). That this isolated gene encodes a nematode glyceraldehyde-3-phosphate dehydrogenase is additionally confirmed by demonstrating its immunoreactivity to an anti-nematode glyceraldehyde-3-phosphate dehydrogenase antibody after its expression as a fusion protein with dihydrofolate reductase. Codon utilization follows a pattern typical of other expressed nematode genes. The gene is split by two introns that are highly conserved in comparison to other introns observed in C. elegans. The placement of one of these introns is conserved with respect to the chicken glyceraldehyde-3-phosphate dehydrogenase gene. Within the 5' flanking sequence homology to actin and the homology 2 block of the major myosin gene (unc-54) is noted. It is of interest that the 3' flanking region contains a CAAAT box, followed by a TATAAT box, before an open reading frame of a closely linked gene that also contains a small AT-rich intron with the nematode consensus splice junction.     

Starvation and temperature upshift cause an increase in the enzymatically active cell wall-associated glyceraldehyde-3-phosphate dehydrogenase protein in yeast

The cell wall-associated glyceraldehyde-3-phosphate dehydrogenase (cwGAPDH) activity in Saccharomyces cerevisiae increases (two- to 10-fold, depending on the strain) in response to starvation and temperature upshift. Assays using transformants carrying pTDH, a yeast centromer derivative plasmid containing the Candida albicans TDH3 gene (encoding GAPDH) fused in frame with the yeast SUC2-coding region for internal invertase, showed that starvation and/or temperature upshift result in a similar increase in both cwGAPDH and cell wall-associated invertase activities. In addition, this incorporation of GAPDH protein into the cell wall in response to stress does not require (i) de novo protein synthesis, indicating that preexisting cytosolic enzyme is incorporated into the cell wall, (ii) nor the participation of the ubiquitin yeast stress response system, as no differences were observed between wild-type and polyubiquitin-depleted (Deltaubi4) strains.     

Effect of ozone on ATP,cytosolic enzymes and permeability of Saccharomyces cerevisiae

Treatment of a yeast suspension with ozone inactivates a number of cytosolic enzymes. Among 15 studied, the most drastic inactivation was found for glyceraldehyde-3-phosphate dehydrogenase and to lesser extents: NAD-glutamate dehydrogenase, pyruvate decarboxylase, phosphofructokinase-1 and NAD-alcohol dehydrogenase. Ozone treatment also effects the quantity of ATP and of other nucleoside triphosphates, reducing to about 50% of the initial value. The ATP missing in the cells appears in the medium. NAD and protein also accumulate in the medium suggesting that the yeast cells have been permeabilized. Permeabilization of the yeast cells by treatment with ozone preceeds the inactivation of glyceraldehyde-3-phosphate dehydrogenase and other cytosolic enzymes.Dedicated to Prof. Dr. B. Hess at the occasion of his 65th birthday     

The glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase of Candida albicans is a surface antigen.

A lambda gt11 cDNA library from Candida albicans ATCC 26555 was screened by using pooled sera from two patients with systemic candidiasis and five neutropenic patients with high levels of anti-C. albicans immunoglobulin M antibodies. Seven clones were isolated from 60,000 recombinant phages. The most reactive one contained a 0.9-kb cDNA encoding a polypeptide immunoreactive only with sera from patients with systemic candidiasis. The whole gene was isolated from a genomic library by using the cDNA as a probe. The nucleotide sequence of the coding region showed homology (78 to 79%) to the Saccharomyces cerevisiae TDH1 to TDH3 genes coding for glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and their amino acid sequences showed 76% identity; thus, this gene has been named C. albicans TDH1. A rabbit polyclonal antiserum against the purified cytosolic C. albicans GAPDH (polyclonal antibody [PAb] anti-CA-GAPDH) was used to identify the GAPDH in the beta-mercaptoethanol extracts containing cell wall moieties. Indirect immunofluorescence demonstrated the presence of GAPDH at the C. albicans cell surface, particularly on the blastoconidia. Semiquantitative flow cytometry analysis showed the sensitivity of this GAPDH form to trypsin and its resistance to be removed with 2 M NaCl or 2% sodium dodecyl sulfate. The decrease in fluorescence in the presence of soluble GAPDH indicates the specificity of the labelling. In addition, a dose-dependent GAPDH enzymatic activity was detected in intact blastoconidia and germ tube cells. This activity was reduced by pretreatment of the cells with trypsin, formaldehyde, and PAb anti-CA-GAPDH. These observations indicate that an immunogenic, enzymatically active cell wall-associated form of the glycolytic enzyme GAPDH is found at the cell surface of C. albicans cells.     

Adjustment of Trehalose Metabolism in Wine Saccharomyces cerevisiae Strains To Modify Ethanol Yields

The ability of Saccharomyces cerevisiae to efficiently produce high levels of ethanol through glycolysis has been the focus of much scientific and industrial activity. Despite the accumulated knowledge regarding glycolysis, the modification of flux through this pathway to modify ethanol yields has proved difficult. Here, we report on the systematic screening of 66 strains with deletion mutations of genes encoding enzymes involved in central carbohydrate metabolism for altered ethanol yields. Five of these strains showing the most prominent changes in carbon flux were selected for further investigation. The genes were representative of trehalose biosynthesis (TPS1, encoding trehalose-6-phosphate synthase), central glycolysis (TDH3, encoding glyceraldehyde-3-phosphate dehydrogenase), the oxidative pentose phosphate pathway (ZWF1, encoding glucose-6-phosphate dehydrogenase), and the tricarboxylic acid (TCA) cycle (ACO1 and ACO2, encoding aconitase isoforms 1 and 2). Two strains exhibited lower ethanol yields than the wild type (tps1Δ and tdh3Δ), while the remaining three showed higher ethanol yields. To validate these findings in an industrial yeast strain, the TPS1 gene was selected as a good candidate for genetic modification to alter flux to ethanol during alcoholic fermentation in wine. Using low-strength promoters active at different stages of fermentation, the expression of the TPS1 gene was slightly upregulated, resulting in a decrease in ethanol production and an increase in trehalose biosynthesis during fermentation. Thus, the mutant screening approach was successful in terms of identifying target genes for genetic modification in commercial yeast strains with the aim of producing lower-ethanol wines.     

Immobilized hybrids of glyceraldehyde-3-phosphate dehydrogenase.

Yeast glyceraldehyde-3-phosphate dehydrogenase (glyceraldehyde-3-phosphate:NAD+ oxidoreductase (phosphorylating), EC 1.2.1.12) immobilized on CNBr-activated Sepharose 4-B has been subjected to dissociation to obtain matrix-bound dimeric species of the enzyme. Hybridization was then performed using soluble glyceraldehyde-3-phosphate dehydrogenase isolated from rat skeletal muscle. Immobilized hybrid tetramers thus obtained were demonstrated to exhibit two distinct pH-optima of activity characteristic of the yeast and muscle enzymes, respectively. The results indicate that under appropriate conditions the activity of each of the dimers composing the immobilized hybrid tetramer can be studied separately.     

Regulation of the glucolytic enzymes inPseudomonas putida

Summary The synthesis of glucose catabolizing enzymes is under inductive control inPseudomonas putida. Glucose, gluconate and 2-ketogluconate are the best nutritional inducers of these enzymes. Mutants unable to catabolize gluconate or 2-ketogluconate synthesized relatively high levels of glucose dehydrogenase and gluconate-6P dehydrase activities when grown in the presence of these substrates. This identifies both compounds as true inducers of these enzymes. KDGP aldolase is induced by its substrate, as evidenced by the inability of mutant cells unable to form KDGP to produce this enzyme at levels above the basal one. A 3-carbon compound appears to be the inducer of glyceraldehyde-3P dehydrogenase. This pattern of regulation suggests that there is a low degree of coordinate control in the synthesis of the glucolytic enzymes byP. putida. This is also supported by the lack of proportionality found in the levels of two enzymes governed by the same inducers, glucose dehydrogenase and gluconate-6P dehydrase, in cells grown on different conditions.Abbrevitions P phosphate - KDGP 2-Keto-3-deoxygluconate-6-phosphate - GDH glucose dehydrogenase - GNDH gluconate dehydrogenase - GK glucokinase - GNK gluconokinase - KGK ketogluconokinase - KGR 2-Ketogluconate-6-phosphate reductase - GPDH glucose-6-phosphate dehydrogenase - GNPD gluconate-6-phosphate dehydrase - KDGPA 2-Keto-3-deoxygluconate-6-phosphate aldolase - GAPDH glyceraldehyde-3-phosphate dehydrogenase