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de Valk SC, Bouwmeester SE, de Hulster E, Mans R. Engineering proton-coupled hexose uptake in Saccharomyces cerevisiae for improved ethanol yield. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:47. [PMID: 35524322 PMCID: PMC9077909 DOI: 10.1186/s13068-022-02145-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 04/16/2022] [Indexed: 11/28/2022]
Abstract
Background In the yeast Saccharomyces cerevisiae, which is widely applied for industrial bioethanol production, uptake of hexoses is mediated by transporters with a facilitated diffusion mechanism. In anaerobic cultures, a higher ethanol yield can be achieved when transport of hexoses is proton-coupled, because of the lower net ATP yield of sugar dissimilation. In this study, the facilitated diffusion transport system for hexose sugars of S. cerevisiae was replaced by hexose–proton symport. Results Introduction of heterologous glucose– or fructose–proton symporters in an hxt0 yeast background strain (derived from CEN.PK2-1C) restored growth on the corresponding sugar under aerobic conditions. After applying an evolutionary engineering strategy to enable anaerobic growth, the hexose–proton symporter-expressing strains were grown in anaerobic, hexose-limited chemostats on synthetic defined medium, which showed that the biomass yield of the resulting strains was decreased by 44.0-47.6%, whereas the ethanol yield had increased by up to 17.2% (from 1.51 to 1.77 mol mol hexose−1) compared to an isogenic strain expressing the hexose uniporter HXT5. To apply this strategy to increase the ethanol yield on sucrose, we constructed a platform strain in which all genes encoding hexose transporters, disaccharide transporters and disaccharide hydrolases were deleted, after which a combination of a glucose–proton symporter, fructose–proton symporter and extracellular invertase (SUC2) were introduced. After evolution, the resulting strain exhibited a 16.6% increased anaerobic ethanol yield (from 1.51 to 1.76 mol mol hexose equivalent−1) and 46.6% decreased biomass yield on sucrose. Conclusions This study provides a proof-of-concept for the replacement of the endogenous hexose transporters of S. cerevisiae by hexose-proton symport, and the concomitant decrease in ATP yield, to greatly improve the anaerobic yield of ethanol on sugar. Moreover, the sugar-negative platform strain constructed in this study acts as a valuable starting point for future studies on sugar transport or development of cell factories requiring specific sugar transport mechanisms. Supplementary Information The online version contains supplementary material available at 10.1186/s13068-022-02145-7.
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Schmidl S, Iancu CV, Reifenrath M, Choe JY, Oreb M. A label-free real-time method for measuring glucose uptake kinetics in yeast. FEMS Yeast Res 2020; 21:6041724. [PMID: 33338229 DOI: 10.1093/femsyr/foaa069] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 12/16/2020] [Indexed: 01/19/2023] Open
Abstract
Glucose uptake assays commonly rely on the isotope-labeled sugar, which is associated with radioactive waste and exposure of the experimenter to radiation. Here, we show that the rapid decrease of the cytosolic pH after a glucose pulse to starved Saccharomyces cerevisiae cells is dependent on the rate of sugar uptake and can be used to determine the kinetic parameters of sugar transporters. The pH-sensitive green fluorescent protein variant pHluorin is employed as a genetically encoded biosensor to measure the rate of acidification as a proxy of transport velocity in real time. The measurements are performed in the hexose transporter-deficient (hxt0) strain EBY.VW4000 that has been previously used to characterize a plethora of sugar transporters from various organisms. Therefore, this method provides an isotope-free, fluorometric approach for kinetic characterization of hexose transporters in a well-established yeast expression system.
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Affiliation(s)
- Sina Schmidl
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Cristina V Iancu
- Department of Chemistry, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC27834, USA
| | - Mara Reifenrath
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Jun-Yong Choe
- Department of Chemistry, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC27834, USA
| | - Mislav Oreb
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
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Kasbawati, Kalondeng A, Sulfahri. A numerical study of the sensitivity of ethanol flux to the existence of co-factors in the Central metabolism of a yeast cell using multi-substrate enzymes kinetic modelling. BIOTECHNOL BIOTEC EQ 2020. [DOI: 10.1080/13102818.2020.1758593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Affiliation(s)
- Kasbawati
- Department of Mathematics, Universitas Hasanuddin, Makassar, Indonesia
| | - Anisa Kalondeng
- Department of Statistics, Universitas Hasanuddin, Makassar, Indonesia
| | - Sulfahri
- Department of Biology, Universitas Hasanuddin, Makassar, Indonesia
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Subtil T, Boles E. Competition between pentoses and glucose during uptake and catabolism in recombinant Saccharomyces cerevisiae. BIOTECHNOLOGY FOR BIOFUELS 2012; 5:14. [PMID: 22424089 PMCID: PMC3364893 DOI: 10.1186/1754-6834-5-14] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 03/16/2012] [Indexed: 05/21/2023]
Abstract
BACKGROUND In mixed sugar fermentations with recombinant Saccharomyces cerevisiae strains able to ferment D-xylose and L-arabinose the pentose sugars are normally only utilized after depletion of D-glucose. This has been attributed to competitive inhibition of pentose uptake by D-glucose as pentose sugars are taken up into yeast cells by individual members of the yeast hexose transporter family. We wanted to investigate whether D-glucose inhibits pentose utilization only by blocking its uptake or also by interfering with its further metabolism. RESULTS To distinguish between inhibitory effects of D-glucose on pentose uptake and pentose catabolism, maltose was used as an alternative carbon source in maltose-pentose co-consumption experiments. Maltose is taken up by a specific maltose transport system and hydrolyzed only intracellularly into two D-glucose molecules. Pentose consumption decreased by about 20 - 30% during the simultaneous utilization of maltose indicating that hexose catabolism can impede pentose utilization. To test whether intracellular D-glucose might impair pentose utilization, hexo-/glucokinase deletion mutants were constructed. Those mutants are known to accumulate intracellular D-glucose when incubated with maltose. However, pentose utilization was not effected in the presence of maltose. Addition of increasing concentrations of D-glucose to the hexo-/glucokinase mutants finally completely blocked D-xylose as well as L-arabinose consumption, indicating a pronounced inhibitory effect of D-glucose on pentose uptake. Nevertheless, constitutive overexpression of pentose-transporting hexose transporters like Hxt7 and Gal2 could improve pentose consumption in the presence of D-glucose. CONCLUSION Our results confirm that D-glucose impairs the simultaneous utilization of pentoses mainly due to inhibition of pentose uptake. Whereas intracellular D-glucose does not seem to have an inhibitory effect on pentose utilization, further catabolism of D-glucose can also impede pentose utilization. Nevertheless, the results suggest that co-fermentation of pentoses in the presence of D-glucose can significantly be improved by the overexpression of pentose transporters, especially if they are not inhibited by D-glucose.
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Affiliation(s)
- Thorsten Subtil
- Institute of Molecular Biosciences, Goethe-University Frankfurt am Main, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany
| | - Eckhard Boles
- Institute of Molecular Biosciences, Goethe-University Frankfurt am Main, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany
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5
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Poulsen AK, Andersen AZ, Brasen JC, Scharff-Poulsen AM, Olsen LF. Probing Glycolytic and Membrane Potential Oscillations in Saccharomyces cerevisiae. Biochemistry 2008; 47:7477-84. [DOI: 10.1021/bi800396e] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Allan K. Poulsen
- CelCom, and Microbiology Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark, and Risoe National Laboratory, Technical University of Denmark, Biosystems Department, Post Office Box 49, Frederiksborgvej 399, DK-4000 Roskilde, Denmark
| | - Ann Zahle Andersen
- CelCom, and Microbiology Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark, and Risoe National Laboratory, Technical University of Denmark, Biosystems Department, Post Office Box 49, Frederiksborgvej 399, DK-4000 Roskilde, Denmark
| | - Jens Christian Brasen
- CelCom, and Microbiology Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark, and Risoe National Laboratory, Technical University of Denmark, Biosystems Department, Post Office Box 49, Frederiksborgvej 399, DK-4000 Roskilde, Denmark
| | - Anne Marie Scharff-Poulsen
- CelCom, and Microbiology Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark, and Risoe National Laboratory, Technical University of Denmark, Biosystems Department, Post Office Box 49, Frederiksborgvej 399, DK-4000 Roskilde, Denmark
| | - Lars Folke Olsen
- CelCom, and Microbiology Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark, and Risoe National Laboratory, Technical University of Denmark, Biosystems Department, Post Office Box 49, Frederiksborgvej 399, DK-4000 Roskilde, Denmark
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6
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Eddy AA, Barnett JA. A history of research on yeasts 11. The study of solute transport: the first 90 years, simple and facilitated diffusion1. Yeast 2007; 24:1023-59. [DOI: 10.1002/yea.1572] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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7
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Rossell S, van der Weijden CC, Kruckeberg AL, Bakker BM, Westerhoff HV. Hierarchical and metabolic regulation of glucose influx in starved Saccharomyces cerevisiae. FEMS Yeast Res 2005; 5:611-9. [PMID: 15780660 DOI: 10.1016/j.femsyr.2004.11.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Revised: 11/01/2004] [Accepted: 11/05/2004] [Indexed: 11/20/2022] Open
Abstract
A novel method dissecting the regulation of a cellular function into direct metabolic regulation and hierarchical (e.g., gene-expression) regulation is applied to yeast starved for nitrogen or carbon. Upon nitrogen starvation glucose influx is down-regulated hierarchically. Upon carbon starvation it is down-regulated both metabolically and hierarchically. The method is expounded in terms of its implications for diverse types of regulation. It is also fine-tuned for cases where isoenzymes catalyze the flux through a single metabolic step.
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Affiliation(s)
- Sergio Rossell
- Department of Molecular Cell Physiology, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, NL-1081 HV Amsterdam, The Netherlands
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8
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Miseta A, Tökés-Füzesi M, Aiello DP, Bedwell DM. A Saccharomyces cerevisiae mutant unable to convert glucose to glucose-6-phosphate accumulates excessive glucose in the endoplasmic reticulum due to core oligosaccharide trimming. EUKARYOTIC CELL 2003; 2:534-41. [PMID: 12796298 PMCID: PMC161446 DOI: 10.1128/ec.2.3.534-541.2003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
D-Glucose is the preferred carbon and energy source for most eukaryotic cells. Immediately following its uptake, glucose is rapidly phosphorylated to glucose-6-phosphate (Glc-6-P). The yeast Saccharomyces cerevisiae has three enzymes (Hxk1p, Hxk2p, and Glk1p) that convert glucose to Glc-6-P. In the present study, we found that yeast mutants lacking any two of these enzymes retain the ability to efficiently convert glucose to Glc-6-P and thus maintain a low level of cellular glucose. However, a mutant strain lacking all three glucose-phosphorylating enzymes contained up to 225-fold more intracellular glucose than normal. Drugs that inhibit the synthesis or the trimming of the lipid-linked core oligosaccharide Glu(3)Man(9)GlcNac(2) effectively reduced the accumulation of glucose. Similarly, mutations that block the addition of glucose residues to the core oligosaccharide moiety, such as alg5Delta or alg6Delta, also diminished glucose accumulation. These results indicate that the intracellular glucose accumulation observed in the glucose phosphorylation mutant results primarily from the trimming of glucose residues from core oligosaccharide chains within the endoplasmic reticulum (ER). Consistent with this conclusion, both [(14)C]glucose exchange and subcellular fractionation experiments indicate that much of the accumulated glucose is retained within an intracellular compartment, suggesting that the efficient transport of glucose from the ER to the cytosol in yeast may be coupled to its rephosphorylation to Glc-6-P. The high level of cellular glucose was associated with an increased level of protein glycation and the release of glucose into the culture medium via its transit through the secretory pathway. Finally, we also found that the accumulation of glucose may lead to a subtle alteration in ion homeostasis, particularly Ca(2+) uptake. This suggests that this mutant strain may serve as a useful model to study the consequences of excessive glucose accumulation and protein glycation.
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Affiliation(s)
- Attila Miseta
- Department of Clinical Chemistry, University Medical School, Peçs, Hungary
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9
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Tökés-Füzesi M, Bedwell DM, Repa I, Sipos K, Sümegi B, Rab A, Miseta A. Hexose phosphorylation and the putative calcium channel component Mid1p are required for the hexose-induced transient elevation of cytosolic calcium response in Saccharomyces cerevisiae. Mol Microbiol 2002; 44:1299-308. [PMID: 12028380 DOI: 10.1046/j.1365-2958.2002.02956.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Saccharomyces cerevisiae responds to environ-mental stimuli such as an exposure to pheromone or to hexoses after carbon source limitation with a transient elevation of cytosolic calcium (TECC) response. In this study, we examined whether hexose transport and phosphorylation are necessary for the TECC response. We found that a mutant strain lacking most of the known hexose transporters was unable to carry out the TECC response when exposed to glucose. A mutant strain that lacked the ability to phosphorylate glucose was unable to respond to glucose addition, but displayed a normal TECC response after the addition of galactose. These results indicate that hexose uptake and phosphorylation are required to trigger the hexose-induced TECC response. We also found that the TECC response was significantly smaller than normal when the level of environmental calcium was reduced, and was abolished in a mid1 mutant that lacked a subunit of the high-affinity calcium channel of the yeast plasma membrane. These results indicate that most or all of the TECC response is mediated by an influx of calcium from the extracellular space. Our results indicate that this transient increase in plasma membrane calcium permeability may be linked to the accumulation of Glc-1-P (or a related glucose metabolite) in yeast.
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Affiliation(s)
- Margit Tökés-Füzesi
- Department of Clinical Chemistry, Faculty of Medicine, Pécs University, 13 Ifjuság u., Pécs 7624, Hungary
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10
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Lange HC, Eman M, van Zuijlen G, Visser D, van Dam JC, Frank J, de Mattos MJ, Heijnen JJ. Improved rapid sampling for in vivo kinetics of intracellular metabolites in Saccharomyces cerevisiae. Biotechnol Bioeng 2001; 75:406-15. [PMID: 11668440 DOI: 10.1002/bit.10048] [Citation(s) in RCA: 159] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
An integrated approach is used to develop a rapid sampling strategy for the quantitative analysis of in vivo kinetic behavior based on measured concentrations of intracellular metabolites in Saccharomyces cerevisiae. Emphasis is laid on small sample sizes during sampling and analysis. Subsecond residence times are accomplished by minimizing the dead volume of the sterile sampling system and by maximizing flow rates through application of vacuum to the sampling tubes in addition to the overpressure in the fermenter. A specially designed sample tube adapter facilitates sampling intervals of 4 to 5 s for various test tube types. Statistical analysis of the results obtained from enzymatic and liquid chromatography mass spectrometry (LC-MSMS) analysis of the metabolite concentrations was used to optimize the sampling protocol. The most notable improvement is reached through the introduction of vacuum drying of the cell extract. The presented system is capable of reliably dealing with fermenter samples as small as 1-g with a variation of less than 3%, and is thus ideally suited for intracellular measurements on small, lab-scale fermenters.
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Affiliation(s)
- H C Lange
- Kluyver Laboratory for Biotechnology, Delft University of Technology, Julianalaan 67, 2628BC Delft, The Netherlands.
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11
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Teusink B, Passarge J, Reijenga CA, Esgalhado E, van der Weijden CC, Schepper M, Walsh MC, Bakker BM, van Dam K, Westerhoff HV, Snoep JL. Can yeast glycolysis be understood in terms of in vitro kinetics of the constituent enzymes? Testing biochemistry. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:5313-29. [PMID: 10951190 DOI: 10.1046/j.1432-1327.2000.01527.x] [Citation(s) in RCA: 464] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This paper examines whether the in vivo behavior of yeast glycolysis can be understood in terms of the in vitro kinetic properties of the constituent enzymes. In nongrowing, anaerobic, compressed Saccharomyces cerevisiae the values of the kinetic parameters of most glycolytic enzymes were determined. For the other enzymes appropriate literature values were collected. By inserting these values into a kinetic model for glycolysis, fluxes and metabolites were calculated. Under the same conditions fluxes and metabolite levels were measured. In our first model, branch reactions were ignored. This model failed to reach the stable steady state that was observed in the experimental flux measurements. Introduction of branches towards trehalose, glycogen, glycerol and succinate did allow such a steady state. The predictions of this branched model were compared with the empirical behavior. Half of the enzymes matched their predicted flux in vivo within a factor of 2. For the other enzymes it was calculated what deviation between in vivo and in vitro kinetic characteristics could explain the discrepancy between in vitro rate and in vivo flux.
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Affiliation(s)
- B Teusink
- E.C. Slater Institute, BioCentrum Amsterdam, University of Amsterdam, the Netherlands
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12
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Jiang H, Medintz I, Zhang B, Michels CA. Metabolic signals trigger glucose-induced inactivation of maltose permease in Saccharomyces. J Bacteriol 2000; 182:647-54. [PMID: 10633097 PMCID: PMC94326 DOI: 10.1128/jb.182.3.647-654.2000] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Organisms such as Saccharomyces capable of utilizing several different sugars selectively ferment glucose when less desirable carbon sources are also available. This is achieved by several mechanisms. Glucose down-regulates the transcription of genes involved in utilization of these alternate carbon sources. Additionally, it causes posttranslational modifications of enzymes and transporters, leading to their inactivation and/or degradation. Two glucose sensing and signaling pathways stimulate glucose-induced inactivation of maltose permease. Pathway 1 uses Rgt2p as a sensor of extracellular glucose and causes degradation of maltose permease protein. Pathway 2 is dependent on glucose transport and stimulates degradation of permease protein and very rapid inactivation of maltose transport activity, more rapid than can be explained by loss of protein alone. In this report, we characterize signal generation through pathway 2 using the rapid inactivation of maltose transport activity as an assay of signaling activity. We find that pathway 2 is dependent on HXK2 and to a lesser extent HXK1. The correlation between pathway 2 signaling and glucose repression suggests that these pathways share common upstream components. We demonstrate that glucose transport via galactose permease is able to stimulate pathway 2. Moreover, rapid transport and fermentation of a number of fermentable sugars (including galactose and maltose, not just glucose) are sufficient to generate a pathway 2 signal. These results indicate that pathway 2 responds to a high rate of sugar fermentation and monitors an intracellular metabolic signal. Production of this signal is not specific to glucose, glucose catabolism, glucose transport by the Hxt transporters, or glucose phosphorylation by hexokinase 1 or 2. Similarities between this yeast glucose sensing pathway and glucose sensing mechanisms in mammalian cells are discussed.
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Affiliation(s)
- H Jiang
- Biology Department, Queens College and the Graduate School of the City University of New York, Flushing, New York 11367, USA
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13
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Diderich JA, Teusink B, Valkier J, Anjos J, Spencer-Martins I, van Dam K, Walsh MC. Strategies to determine the extent of control exerted by glucose transport on glycolytic flux in the yeast Saccharomyces bayanus. MICROBIOLOGY (READING, ENGLAND) 1999; 145 ( Pt 12):3447-3454. [PMID: 10627042 DOI: 10.1099/00221287-145-12-3447] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The extent to which the transport of glucose across the plasma membrane of the yeast Saccharomyces bayanus controls the glycolytic flux was determined. The magnitude of control was quantified by measuring the effect of small changes in the activity of the glucose transport system on the rate of glucose consumption. Two effectors were used to modulate the activity of glucose transport: (i) maltose, a competitive inhibitor of the glucose transport system in S. bayanus (as well as in Saccharomyces cerevisiae) and (ii) extracellular glucose, the substrate of the glucose transport system. Two approaches were followed to derive from the experimental data the flux control coefficient of glucose transport on the glycolytic flux: (i) direct comparison of the steady-state glycolytic flux with the zero trans-influx of glucose and (ii) comparison of the change in glycolytic flux with the concomitant change in calculated glucose transport activity on variation of the extracellular glucose concentration. Both these approaches demonstrated that in cells of S. bayanus grown on glucose and harvested at the point of glucose exhaustion, a high proportion of the control of the glycolytic flux resides in the transport of glucose across the plasma membrane.
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Affiliation(s)
- Jasper A Diderich
- E. C. Slater Institute, BioCentrum, University of Amsterdam, Plantage Muidergracht 12, NL-1018 TV Amsterdam, The Netherlands1
| | - Bas Teusink
- E. C. Slater Institute, BioCentrum, University of Amsterdam, Plantage Muidergracht 12, NL-1018 TV Amsterdam, The Netherlands1
| | - Jeroen Valkier
- E. C. Slater Institute, BioCentrum, University of Amsterdam, Plantage Muidergracht 12, NL-1018 TV Amsterdam, The Netherlands1
| | - Jorge Anjos
- Biotechnology Unit, Faculty of Sciences and Technology, New University of Lisbon, P-2825 Monte de Caparica, Portugal 2
| | - Isabel Spencer-Martins
- Biotechnology Unit, Faculty of Sciences and Technology, New University of Lisbon, P-2825 Monte de Caparica, Portugal 2
| | - Karel van Dam
- E. C. Slater Institute, BioCentrum, University of Amsterdam, Plantage Muidergracht 12, NL-1018 TV Amsterdam, The Netherlands1
| | - Michael C Walsh
- E. C. Slater Institute, BioCentrum, University of Amsterdam, Plantage Muidergracht 12, NL-1018 TV Amsterdam, The Netherlands1
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14
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Diderich JA, Schepper M, van Hoek P, Luttik MA, van Dijken JP, Pronk JT, Klaassen P, Boelens HF, de Mattos MJ, van Dam K, Kruckeberg AL. Glucose uptake kinetics and transcription of HXT genes in chemostat cultures of Saccharomyces cerevisiae. J Biol Chem 1999; 274:15350-9. [PMID: 10336421 DOI: 10.1074/jbc.274.22.15350] [Citation(s) in RCA: 170] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The kinetics of glucose transport and the transcription of all 20 members of the HXT hexose transporter gene family were studied in relation to the steady state in situ carbon metabolism of Saccharomyces cerevisiae CEN.PK113-7D grown in chemostat cultures. Cells were cultivated at a dilution rate of 0.10 h-1 under various nutrient-limited conditions (anaerobically glucose- or nitrogen-limited or aerobically glucose-, galactose-, fructose-, ethanol-, or nitrogen-limited), or at dilution rates ranging between 0.05 and 0.38 h-1 in aerobic glucose-limited cultures. Transcription of HXT1-HXT7 was correlated with the extracellular glucose concentration in the cultures. Transcription of GAL2, encoding the galactose transporter, was only detected in galactose-limited cultures. SNF3 and RGT2, two members of the HXT family that encode glucose sensors, were transcribed at low levels. HXT8-HXT17 transcripts were detected at very low levels. A consistent relationship was observed between the expression of individual HXT genes and the glucose transport kinetics determined from zero-trans influx of 14C-glucose during 5 s. This relationship was in broad agreement with the transport kinetics of Hxt1-Hxt7 and Gal2 deduced in previous studies on single-HXT strains. At lower dilution rates the glucose transport capacity estimated from zero-trans influx experiments and the residual glucose concentration exceeded the measured in situ glucose consumption rate. At high dilution rates, however, the estimated glucose transport capacity was too low to account for the in situ glucose consumption rate.
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Affiliation(s)
- J A Diderich
- E. C. Slater Institute, University of Amsterdam, Plantage Muidergracht 12, 1018 TV Amsterdam, The Netherlands
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15
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Meijer MM, Boonstra J, Verkleij AJ, Verrips CT. Glucose repression in Saccharomyces cerevisiae is related to the glucose concentration rather than the glucose flux. J Biol Chem 1998; 273:24102-7. [PMID: 9727030 DOI: 10.1074/jbc.273.37.24102] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glucose plays an important regulatory role in the yeast Saccharomyces cerevisiae, which is mostly reflected at the transcriptional level by glucose repression. The signal that initiates glucose repression is unknown, but data indicate that it is located at or above the level of glucose 6-phosphate, suggesting the involvement of either the intracellular or extracellular glucose concentration or the glucose flux in triggering glucose repression. We have investigated the role of the glucose flux and the extracellular glucose concentration in glucose repression by growing the cells in continuous culture under nitrogen limitation. By a step-wise increase in the glucose feed concentration, the glucose flux and extracellular glucose concentrations were modulated in an accurate way. Furthermore, the glucose flux and glucose concentrations were modulated independently of each other by increasing the dilution rate or by the use of fructose as a substrate. Using these approaches we demonstrate that glucose repression is related to the extracellular (or intracellular) glucose concentration rather than the glucose flux. At external glucose concentrations lower than 14 mM, glucose repression of SUC2 gene transcription was not triggered, whereas glucose repression of this gene was activated when the glucose concentration exceeded 18 mM. A comparable effect was observed for the glucose-repressible carbon source fructose.
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Affiliation(s)
- M M Meijer
- Utrecht University, Department of Molecular Cell Biology/Institute for Biomembranes, Padualaan 8, 3584 CH Utrecht, The Netherlands.
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16
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Smits HP, Cohen A, Buttler T, Nielsen J, Olsson L. Cleanup and analysis of sugar phosphates in biological extracts by using solid-phase extraction and anion-exchange chromatography with pulsed amperometric detection. Anal Biochem 1998; 261:36-42. [PMID: 9683509 DOI: 10.1006/abio.1998.2714] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A cleanup method based on anion-exchange solid-phase extraction (SPE) was developed to render biological extracts suitable for the analysis of hexose phosphates with a modified anion-exchange chromatography method and pulsed amperometric detection. The method was applied to cell extracts of Saccharomyces cerevisiae obtained by using cold methanol as quenching agent and chloroform as extraction solvent. It was shown that pretreatment of the cell extract with SPE markedly improved the quality of the liquid chromatography analysis with recoveries of the sugar phosphates close to 100%. Furthermore, the method allowed for sample enrichment and the original extraction procedure could be simplified by implementing SPE early in the extraction protocol.
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Affiliation(s)
- H P Smits
- Department of Biotechnology, Technical University of Denmark, Building 223, Lyngby DK-2800, Denmark
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Teusink B, Diderich JA, Westerhoff HV, van Dam K, Walsh MC. Intracellular glucose concentration in derepressed yeast cells consuming glucose is high enough to reduce the glucose transport rate by 50%. J Bacteriol 1998; 180:556-62. [PMID: 9457857 PMCID: PMC106921 DOI: 10.1128/jb.180.3.556-562.1998] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In Saccharomyces cerevisiae cells exhibiting high-affinity glucose transport, the glucose consumption rate at extracellular concentrations above 10 mM was only half of the zero trans-influx rate. To determine if this regulation of glucose transport might be a consequence of intracellular free glucose we developed a new method to measure intracellular glucose concentrations in cells metabolizing glucose, which compares glucose stereoisomers to correct for adhering glucose. The intracellular glucose concentration was 1.5 mM, much higher than in most earlier reports. We show that for the simplest model of a glucose carrier, this concentration is sufficient to reduce the glucose influx by 50%. We conclude that intracellular glucose is the most likely candidate for the observed regulation of glucose import and hence glycolysis. We discuss the possibility that intracellular glucose functions as a primary signal molecule in these cells.
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Affiliation(s)
- B Teusink
- E. C. Slater Institute, BioCentrum, University of Amsterdam, The Netherlands
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Abstract
Transport across the plasma membrane is the first, obligatory step of hexose utilization. In yeast cells the uptake of hexoses is mediated by a large family of related transporter proteins. In baker's yeast Saccharomyces cerevisiae the genes of 20 different hexose transporter-related proteins have been identified. Six of these transmembrane proteins mediate the metabolically relevant uptake of glucose, fructose and mannose for growth, two others catalyze the transport of only small amounts of these sugars, one protein is a galactose transporter but also able to transport glucose, two transporters act as glucose sensors, two others are involved in the pleiotropic drug resistance process, and the functions of the remaining hexose transporter-related proteins are not yet known. The catabolic hexose transporters exhibit different affinities for their substrates, and expression of their corresponding genes is controlled by the glucose sensors according to the availability of carbon sources. In contrast, milk yeast Kluyveromyces lactis contains only a few different hexose transporters. Genes of other monosaccharide transporter-related proteins have been found in fission yeast Schizosaccharomyces pombe and in the xylose-fermenting yeast Pichia stipitis. However, the molecular genetics of hexose transport in many other yeasts remains to be established. The further characterization of this multigene family of hexose transporters should help to elucidate the role of transport in yeast sugar metabolism.
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Affiliation(s)
- E Boles
- Institut für Mikrobiologie, Heinrich-Heine-Universität, Düsseldorf, Germany.
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Affiliation(s)
- J Horák
- Department of Membrane Transport, Czech Academy of Sciences, Prague, Czech Republic
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