scholarly journals Osmoregulation in Saccharomyces cerevisiae via mechanisms other than the high-osmolarity glycerol pathway

Microbiology ◽  
2016 ◽  
Vol 162 (9) ◽  
pp. 1511-1526 ◽  
Author(s):  
Abhishek Saxena ◽  
Ramakrishnan Sitaraman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
High Osmolarity ◽  
High Osmolarity Glycerol ◽  
High Osmolarity Glycerol Pathway

GPD1, which encodes glycerol-3-phosphate dehydrogenase, is essential for growth under osmotic stress in Saccharomyces cerevisiae, and its expression is regulated by the high-osmolarity glycerol response pathway

1994 ◽  
Vol 14 (6) ◽  
pp. 4135-4144
Author(s):  
J Albertyn ◽  
S Hohmann ◽  
J M Thevelein ◽  
B A Prior
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Osmotic Stress ◽  
Yeast Cells ◽  
Mrna Levels ◽  
Hog Pathway ◽  
Hypertonic Medium ◽  
High Osmolarity ◽  
High Osmolarity Glycerol ◽  
Enhanced Production ◽  
Glycerol 3 Phosphate Dehydrogenase

The yeast Saccharomyces cerevisiae responds to osmotic stress, i.e., an increase in osmolarity of the growth medium, by enhanced production and intracellular accumulation of glycerol as a compatible solute. We have cloned a gene encoding the key enzyme of glycerol synthesis, the NADH-dependent cytosolic glycerol-3-phosphate dehydrogenase, and we named it GPD1. gpd1 delta mutants produced very little glycerol, and they were sensitive to osmotic stress. Thus, glycerol production is indeed essential for the growth of yeast cells during reduced water availability. hog1 delta mutants lacking a protein kinase involved in osmostress-induced signal transduction (the high-osmolarity glycerol response [HOG] pathway) failed to increase glycerol-3-phosphate dehydrogenase activity and mRNA levels when osmotic stress was imposed. Thus, expression of GPD1 is regulated through the HOG pathway. However, there may be Hog1-independent mechanisms mediating osmostress-induced glycerol accumulation, since a hog1 delta strain could still enhance its glycerol content, although less than the wild type. hog1 delta mutants are more sensitive to osmotic stress than isogenic gpd1 delta strains, and gpd1 delta hog1 delta double mutants are even more sensitive than either single mutant. Thus, the HOG pathway most probably has additional targets in the mechanism of adaptation to hypertonic medium.

scholarly journals Yeast osmosensor Sln1 and plant cytokinin receptor Cre1 respond to changes in turgor pressure

2003 ◽  
Vol 161 (6) ◽  
pp. 1035-1040 ◽  
Author(s):  
Vladimír Reiser ◽  
Desmond C. Raitt ◽  
Haruo Saito
Keyword(s):  
Cell Wall ◽  
Stress Responses ◽  
Histidine Kinase ◽  
Turgor Pressure ◽  
Hyperosmotic Stress ◽  
Cytokinin Receptor ◽  
High Osmolarity ◽  
High Osmolarity Glycerol ◽  
High Osmolarity Glycerol Pathway ◽  
Cytokinin Response

Very little is known about how cellular osmosensors monitor changes in osmolarity of the environment. Here, we report that in yeast, Sln1 osmosensor histidine kinase monitors changes in turgor pressures. Reductions in turgor caused by either hyperosmotic stress, nystatin, or removal of cell wall activate MAPK Hog1 specifically through the SLN1 branch, but not through the SHO1 branch of the high osmolarity glycerol pathway. The integrity of the periplasmic region of Sln1 was essential for its sensor function. We found that activity of the plant histidine kinase cytokinin response 1 (Cre1) is also regulated by changes in turgor pressure, in a manner identical to that of Sln1, in the presence of cytokinin. We propose that Sln1 and Cre1 are turgor sensors, and that similar turgor-sensing mechanisms might regulate hyperosmotic stress responses both in yeast and plants.

Agents that activate the High Osmolarity Glycerol pathway as a means to combat pathogenic molds

2016 ◽  
Vol 306 (8) ◽  
pp. 642-651 ◽  
Author(s):  
Annegret Wiedemann ◽  
Anja Spadinger ◽  
Axel Löwe ◽  
Allison Seeger ◽  
Frank Ebel
Keyword(s):  
High Osmolarity ◽  
High Osmolarity Glycerol ◽  
High Osmolarity Glycerol Pathway

scholarly journals Calcofluor Antifungal Action Depends on Chitin and a Functional High-Osmolarity Glycerol Response (HOG) Pathway: Evidence for a Physiological Role of the Saccharomyces cerevisiae HOG Pathway under Noninducing Conditions

2000 ◽  
Vol 182 (9) ◽  
pp. 2428-2437 ◽  
Author(s):  
L. J. García-Rodriguez ◽  
A. Durán ◽  
C. Roncero
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Protein Kinase ◽  
Salt Tolerance ◽  
Map Kinases ◽  
Physiological Role ◽  
Hog Pathway ◽  
High Osmolarity ◽  
High Osmolarity Glycerol

ABSTRACT We have isolated several Saccharomyces cerevisiaemutants resistant to calcofluor that contain mutations in thePBS2 or HOG1 genes, which encode the mitogen-activated protein kinase (MAPK) and MAP kinases, respectively, of the high-osmolarity glycerol response (HOG) pathway. We report that blockage of either of the two activation branches of the pathway, namely, SHO1 and SLN1, leads to partial resistance to calcofluor, while simultaneous disruption significantly increases resistance. However, chitin biosynthesis is independent of the HOG pathway. Calcofluor treatment also induces an increase in salt tolerance and glycerol accumulation, although no activation of the HOG pathway is detected. Our results indicate that the antifungal effect of calcofluor depends on its binding to cell wall chitin but also on the presence of a functional HOG pathway. Characterization of one of the mutants isolated, pbs2-14, revealed that resistance to calcofluor and HOG-dependent osmoadaptation are two different physiological processes. Sensitivity to calcofluor depends on the constitutive functionality of the HOG pathway; when this is altered, the cells become calcofluor resistant but also show very low levels of basal salt tolerance. Characterization of some multicopy suppressors of the calcofluor resistance phenotype indicated that constitutive HOG functionality participates in the maintenance of cell wall architecture, a conclusion supported by the antagonism observed between the protein kinase and HOG signal transduction pathways.

scholarly journals Cooperative Regulation of DOG2, Encoding 2-Deoxyglucose-6-Phosphate Phosphatase, by Snf1 Kinase and the High-Osmolarity Glycerol–Mitogen-Activated Protein Kinase Cascade in Stress Responses of Saccharomyces cerevisiae

2000 ◽  
Vol 182 (18) ◽  
pp. 5121-5126 ◽  
Author(s):  
Yoshiyuki Tsujimoto ◽  
Shingo Izawa ◽  
Yoshiharu Inoue
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Saccharomyces Cerevisiae ◽  
Osmotic Stress ◽  
Mitogen Activated Protein Kinase ◽  
High Osmolarity ◽  
High Osmolarity Glycerol ◽  
Mitogen Activated Protein ◽  
Kinase Cascade ◽  
Protein Kinase Cascade

ABSTRACT We screened the genome of Saccharomyces cerevisiae for the genes responsive to oxidative stress by using the lacZtransposon-insertion library. As a result, we found that expression of the DOG2 gene coding for 2-deoxyglucose-6-phosphate phosphatase was induced by oxidative stress. The expression ofDOG2 was also induced by osmotic stress. We found a putative cis element (STRE, a stress response element) in the DOG2 promoter adjacent to a consensus sequence to which the Mig1p repressor is known to bind. The basal levels ofDOG2 gene expression were increased in amig1Δ mutant, while the derepression of DOG2was not observed in a snf1Δ mutant under glucose-deprived conditions. Induction of the DOG2 gene expression by osmotic stress was observed in any of the three disruptantspbs2Δ, hog1Δ, and snf1Δ. However, the osmotic induction was completely abolished in both thesnf1Δ pbs2Δ mutant and the snf1Δ hog1Δ mutant. Additionally, these single mutants as well as double mutants failed to induce DOG2 expression by oxidative stress. These results suggest that Snf1p kinase and the high-osmolarity glycerol–mitogen-activated protein kinase cascade are likely to be involved in the signaling pathway of oxidative stress and osmotic stress in regulation of DOG2.

scholarly journals GPD1, which encodes glycerol-3-phosphate dehydrogenase, is essential for growth under osmotic stress in Saccharomyces cerevisiae, and its expression is regulated by the high-osmolarity glycerol response pathway.

1994 ◽  
Vol 14 (6) ◽  
pp. 4135-4144 ◽  
Author(s):  
J Albertyn ◽  
S Hohmann ◽  
J M Thevelein ◽  
B A Prior
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Osmotic Stress ◽  
Yeast Cells ◽  
Mrna Levels ◽  
Hog Pathway ◽  
Hypertonic Medium ◽  
High Osmolarity ◽  
High Osmolarity Glycerol ◽  
Enhanced Production ◽  
Glycerol 3 Phosphate Dehydrogenase

The yeast Saccharomyces cerevisiae responds to osmotic stress, i.e., an increase in osmolarity of the growth medium, by enhanced production and intracellular accumulation of glycerol as a compatible solute. We have cloned a gene encoding the key enzyme of glycerol synthesis, the NADH-dependent cytosolic glycerol-3-phosphate dehydrogenase, and we named it GPD1. gpd1 delta mutants produced very little glycerol, and they were sensitive to osmotic stress. Thus, glycerol production is indeed essential for the growth of yeast cells during reduced water availability. hog1 delta mutants lacking a protein kinase involved in osmostress-induced signal transduction (the high-osmolarity glycerol response [HOG] pathway) failed to increase glycerol-3-phosphate dehydrogenase activity and mRNA levels when osmotic stress was imposed. Thus, expression of GPD1 is regulated through the HOG pathway. However, there may be Hog1-independent mechanisms mediating osmostress-induced glycerol accumulation, since a hog1 delta strain could still enhance its glycerol content, although less than the wild type. hog1 delta mutants are more sensitive to osmotic stress than isogenic gpd1 delta strains, and gpd1 delta hog1 delta double mutants are even more sensitive than either single mutant. Thus, the HOG pathway most probably has additional targets in the mechanism of adaptation to hypertonic medium.

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