Conditions with high intracellular glucose inhibit sensing through glucose sensor Snf3 in Saccharomyces cerevisiae

2010 ◽  
Vol 110 (4) ◽  
pp. 920-925 ◽  
Author(s):  
Kaisa Karhumaa ◽  
Boqian Wu ◽  
Morten C. Kielland-Brandt
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Glucose Sensor ◽  
Intracellular Glucose

scholarly journals Cultivation of Saccharomyces cerevisiae with Feedback Regulation of Glucose Concentration Controlled by Optical Fiber Glucose Sensor

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 565
Author(s):  
Lucie Koštejnová ◽  
Jakub Ondráček ◽  
Petra Majerová ◽  
Martin Koštejn ◽  
Gabriela Kuncová ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Optical Fiber ◽  
Glucose Concentration ◽  
Glucose Sensor ◽  
Ruthenium Complex ◽  
Feedback Regulation ◽  
Regulation System ◽  
Sensitive Layer ◽  
Average Deviation ◽  
Glucose Content

Glucose belongs among the most important substances in both physiology and industry. Current food and biotechnology praxis emphasizes its on-line continuous monitoring and regulation. These provoke increasing demand for systems, which enable fast detection and regulation of deviations from desired glucose concentration. We demonstrated control of glucose concentration by feedback regulation equipped with in situ optical fiber glucose sensor. The sensitive layer of the sensor comprises oxygen-dependent ruthenium complex and preimmobilized glucose oxidase both entrapped in organic–inorganic polymer ORMOCER®. The sensor was placed in the laboratory bioreactor (volume 5 L) to demonstrate both regulations: the control of low levels of glucose concentrations (0.4 and 0.1 mM) and maintenance of the glucose concentration (between 2 and 3.5 mM) during stationary phase of cultivation of Saccharomyces cerevisiae. Response times did not exceed 6 min (average 4 min) with average deviation of 4%. Due to these regulation characteristics together with durable and long-lasting (≥2 month) sensitive layer, this feedback regulation system might find applications in various biotechnological processes such as production of low glucose content beverages.

scholarly journals Rgt1p of Saccharomyces cerevisiae, a key regulator of glucose-induced genes, is both an activator and a repressor of transcription.

1996 ◽  
Vol 16 (11) ◽  
pp. 6419-6426 ◽  
Author(s):  
S Ozcan ◽  
T Leong ◽  
M Johnston
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Glucose Transporter ◽  
Glucose Sensor ◽  
Glucose Sensors ◽  
Hexose Transporter ◽  
Glucose Signaling ◽  
Low Glucose ◽  
Induced Genes ◽  
Low Levels ◽  
High Concentrations

The RGT1 gene of Saccharomyces cerevisiae plays a central role in the glucose-induced expression of hexose transporter (HXT) genes. Genetic evidence suggests that it encodes a repressor of the HXT genes whose function is inhibited by glucose. Here, we report the isolation of RGT1 and demonstrate that it encodes a bifunctional transcription factor. Rgt1p displays three different transcriptional modes in response to glucose: (i) in the absence of glucose, it functions as a transcriptional repressor; (ii) high concentrations of glucose cause it to function as a transcriptional activator; and (iii) in cells growing on low levels of glucose, Rgt1p has a neutral role, neither repressing nor activating transcription. Glucose alters Rgt1p function through a pathway that includes two glucose sensors, Snf3p and Rgt2p, and Grr1p. The glucose transporter Snf3p, which appears to be a low-glucose sensor, is required for inhibition of Rgt1p repressor function by low levels of glucose. Rgt2p, a glucose transporter that functions as a high-glucose sensor, is required for conversion of Rgt1p into an activator by high levels of glucose. Grr1p, a component of the glucose signaling pathway, is required both for inactivation of Rgt1p repressor function by low levels of glucose and for conversion of Rgt1p into an activator at high levels of glucose. Thus, signals generated by two different glucose sensors act through Grr1p to determine Rgt1p function.

scholarly journals Hexokinase 2 Is an Intracellular Glucose Sensor of Yeast Cells That Maintains the Structure and Activity of Mig1 Protein Repressor Complex

2016 ◽  
Vol 291 (14) ◽  
pp. 7267-7285 ◽  
Author(s):  
Montserrat Vega ◽  
Alberto Riera ◽  
Alejandra Fernández-Cid ◽  
Pilar Herrero ◽  
Fernando Moreno
Keyword(s):  
Glucose Sensor ◽  
Yeast Cells ◽  
Hexokinase 2 ◽  
Repressor Complex ◽  
Structure And Activity ◽  
Intracellular Glucose

scholarly journals Hxt-Carrier-Mediated Glucose Efflux upon Exposure of Saccharomyces cerevisiae to Excess Maltose

2002 ◽  
Vol 68 (9) ◽  
pp. 4259-4265 ◽  
Author(s):  
Mickel L. A. Jansen ◽  
Johannes H. De Winde ◽  
Jack T. Pronk
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Reference Strain ◽  
External Medium ◽  
Hexose Transport ◽  
Hexose Transporter ◽  
Wild Type ◽  
Experimental Proof ◽  
Chemostat Cultures ◽  
Selection Of ◽  
Intracellular Glucose

ABSTRACT When wild-type Saccharomyces cerevisiae strains pregrown in maltose-limited chemostat cultures were exposed to excess maltose, release of glucose into the external medium was observed. Control experiments confirmed that glucose release was not caused by cell lysis or extracellular maltose hydrolysis. To test the hypothesis that glucose efflux involved plasma membrane glucose transporters, experiments were performed with an S. cerevisiae strain in which all members of the hexose transporter (HXT) gene family had been eliminated and with an isogenic reference strain. Glucose efflux was virtually eliminated in the hexose-transport-deficient strain. This constitutes experimental proof that Hxt transporters facilitate export of glucose from S. cerevisiae cells. After exposure of the hexose-transport-deficient strain to excess maltose, an increase in the intracellular glucose level was observed, while the concentrations of glucose 6-phosphate and ATP remained relatively low. These results demonstrate that glucose efflux can occur as a result of uncoordinated expression of the initial steps of maltose metabolism and the subsequent reactions in glucose dissimilation. This is a relevant phenomenon for selection of maltose-constitutive strains for baking and brewing.

Saccharomyces cerevisiae glucose signalling regulator Mth1p regulates the organellar Na+/H+ exchanger Nhx1p

2010 ◽  
Vol 432 (2) ◽  
pp. 343-352 ◽  
Author(s):  
Keiji Mitsui ◽  
Masafumi Matsushita ◽  
Hiroshi Kanazawa
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Glucose Sensor ◽  
Ph Regulation ◽  
Gene Knockout ◽  
Carbon Sources ◽  
Acidic Ph ◽  
In Cells

Organelle-localized NHEs (Na+/H+ exchangers) are found in cells from yeast to humans and contribute to organellar pH regulation by exporting H+ from the lumen to the cytosol coupled to an H+ gradient established by vacuolar H+-ATPase. The mechanisms underlying the regulation of organellar NHEs are largely unknown. In the present study, a yeast two-hybrid assay identified Mth1p as a new binding protein for Nhx1p, an organellar NHE in Saccharomyces cerevisiae. It was shown by an in vitro pull-down assay that Mth1p bound to the hydrophilic C-terminal half of Nhx1p, especially to the central portion of this region. Mth1p is known to bind to the cytoplasmic domain of the glucose sensor Snf3p/Rgt2p and also functions as a negative transcriptional regulator. Mth1p was expressed in cells grown in a medium containing galactose, but was lost (possibly degraded) when cells were grown in medium containing glucose as the sole carbon source. Deletion of the MTH1 gene increased cell growth compared with the wild-type when cells were grown in a medium containing galactose and with hygromycin or at an acidic pH. This resistance to hygromycin or acidic conditions was not observed for cells grown with glucose as the sole carbon source. Gene knockout of NHX1 increased the sensitivity to hygromycin and acidic pH. The increased resistance to hygromycin was reproduced by truncation of the Mth1p-binding region in Nhx1p. These results implicate Mth1p as a novel regulator of Nhx1p that responds to specific extracellular carbon sources.

scholarly journals A polymer-based ratiometric intracellular glucose sensor

2014 ◽  
Vol 50 (52) ◽  
pp. 6920-6922 ◽  
Author(s):  
Liqiang Zhang ◽  
Fengyu Su ◽  
Sean Buizer ◽  
Xiangxing Kong ◽  
Fred Lee ◽  
...  
Keyword(s):  
Hela Cells ◽  
Glucose Sensor ◽  
Intracellular Glucose

A new polymeric ratiometric glucose sensor was synthesized and used for dynamically monitoring intracellular glucose concentrations in HeLa cells.

scholarly journals Glycolysis Controls Plasma Membrane Glucose Sensors To Promote Glucose Signaling in Yeasts

2014 ◽  
Vol 35 (4) ◽  
pp. 747-757 ◽  
Author(s):  
Amélie Cairey-Remonnay ◽  
Julien Deffaud ◽  
Micheline Wésolowski-Louvel ◽  
Marc Lemaire ◽  
Alexandre Soulard
Keyword(s):  
Signaling Pathway ◽  
Glucose Sensor ◽  
Kluyveromyces Lactis ◽  
Glucose Sensors ◽  
Content Type ◽  
Glucose Signaling ◽  
Extracellular Glucose ◽  
Glucose Accumulation ◽  
The Stability ◽  
Intracellular Glucose

Sensing of extracellular glucose is necessary for cells to adapt to glucose variation in their environment. In the respiratory yeastKluyveromyces lactis, extracellular glucose controls the expression of major glucose permease geneRAG1through a cascade similar to theSaccharomyces cerevisiaeSnf3/Rgt2/Rgt1 glucose signaling pathway. This regulation depends also on intracellular glucose metabolism since we previously showed that glucose induction of theRAG1gene is abolished in glycolytic mutants. Here we show that glycolysis regulatesRAG1expression through theK. lactisRgt1 (KlRgt1) glucose signaling pathway by targeting the localization and probably the stability of Rag4, the single Snf3/Rgt2-type glucose sensor ofK. lactis. Additionally, the control exerted by glycolysis on glucose signaling seems to be conserved inS. cerevisiae. This retrocontrol might prevent yeasts from unnecessary glucose transport and intracellular glucose accumulation.

scholarly journals Pharmacological activation of pyruvate kinase M2 reprograms glycolysis leading to TXNIP depletion and AMPK activation in breast cancer cells

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Fadi Almouhanna ◽  
Biljana Blagojevic ◽  
Suzan Can ◽  
Ali Ghanem ◽  
Stefan Wölfl
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Pyruvate Kinase ◽  
Breast Cancer Cells ◽  
Glucose Sensor ◽  
Nutrient Sensing ◽  
Metabolic Reprogramming ◽  
Metabolic Inhibitors ◽  
Breast Cancer Cell Lines ◽  
Intracellular Glucose

Abstract Background Aerobic glycolysis, discovered by Otto Warburg, is a hallmark of cancer metabolism even though not yet fully understood. The low activity of the cancerous pyruvate kinase isozyme (M2) is thought to play an important role by facilitating the conversion of glycolytic intermediates to other anabolic pathways to support tumors’ high proliferation rate. Methods Five breast cancer cell lines representing different molecular subtypes were used in this study where real time measurements of cellular bioenergetics and immunoblotting analysis of energy- and nutrient-sensing pathways were employed to investigate the potential effects of PKM2 allosteric activator (DASA-58) in glucose rewiring. Results In this study, we show that DASA-58 can induce pyruvate kinase activity in breast cancer cells without affecting the overall cell survival. The drug is also able to reduce TXNIP levels (an intracellular glucose sensor) probably through depletion of upstream glycolytic metabolites and independent of AMPK and ER signaling. AMPK shows an induction in phosphorylation (T172) in response to treatment an effect that can be potentiated by combining DASA-58 with other metabolic inhibitors. Conclusions Altogether, the multifaceted metabolic reprogramming induced by DASA-58 in breast cancer cells increases their susceptibility to other therapeutics suggesting the suitability of the intracellular glucose sensor TXNIP as a marker of PK activity.

scholarly journals Transcriptional Response of Saccharomyces cerevisiae to Desiccation and Rehydration

2005 ◽  
Vol 71 (12) ◽  
pp. 8752-8763 ◽  
Author(s):  
Jatinder Singh ◽  
Deept Kumar ◽  
Naren Ramakrishnan ◽  
Vibha Singhal ◽  
Jody Jervis ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Sulfur Metabolism ◽  
Glyoxylate Cycle ◽  
Transcriptional Response ◽  
Transcriptional Analysis ◽  
Acid Oxidation ◽  
Expression Of Genes ◽  
Metabolic States ◽  
Two Samples ◽  
Intracellular Glucose

ABSTRACT A transcriptional analysis of the response of Saccharomyces cerevisiae strain BY4743 to controlled air-drying (desiccation) and subsequent rehydration under minimal glucose conditions was performed. Expression of genes involved in fatty acid oxidation and the glyoxylate cycle was observed to increase during drying and remained in this state during the rehydration phase. When the BY4743 expression profile for the dried sample was compared to that of a commercially prepared dry active yeast, strikingly similar expression changes were observed. The fact that these two samples, dried by different means, possessed very similar transcriptional profiles supports the hypothesis that the response to desiccation is a coordinated event independent of the particular conditions involved in water removal. Similarities between “stationary-phase-essential genes” and those upregulated during desiccation were also noted, suggesting commonalities in different routes to reduced metabolic states. Trends in extracellular and intracellular glucose and trehalose levels suggested that the cells were in a “holding pattern” during the rehydration phase, a concept that was reinforced by cell cycle analyses. Application of a “redescription mining” algorithm suggested that sulfur metabolism is important for cell survival during desiccation and rehydration.

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