scholarly journals A novel signal transduction pathway in Saccharomyces cerevisiae defined by Snf3-regulated expression of HXT6.

1996 ◽  
Vol 7 (12) ◽  
pp. 1953-1966 ◽  
Author(s):  
H Liang ◽  
R F Gaber
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Signal Transduction ◽  
Glucose Uptake ◽  
Glucose Repression ◽  
Carbon Sources ◽  
Signal Transduction Pathway ◽  
Transduction Pathway ◽  
Signaling Mechanism ◽  
High Concentrations ◽  
Delta Cells

We show that cells deleted for SNF3, HXT1, HXT2, HXT3, HXT4, HXT6, and HXT7 do not take up glucose and cannot grow on media containing glucose as a sole carbon source. The expression of Hxt1, Hxt2, Hxt3, Hxt6, or Gal2 in these cells resulted in glucose transport and allowed growth on glucose media. In contrast, the expression of Snf3 failed to confer glucose uptake or growth on glucose. HXT6 is highly expressed on raffinose, low glucose, or nonfermentable carbon sources but is repressed in the presence of high concentrations of glucose. The maintenance of HXT6 glucose repression is strictly dependent on Snf3 and not on intracellular glucose. In snf3 delta cells expression of HXT6 is constitutive even when the entire repertoire of HXT genes is present and glucose uptake is abundant. In addition, glucose repression of HXT6 does not require glucose uptake by HXT1, HXT2, HXT3 or HXT4. We show that a signal transduction pathway defined by the Snf3-dependent hexose regulation of HXT6 is distinct from but also overlaps with general glucose regulation pathways in Saccharomyces cerevisiae. Finally, glucose repression of ADH2 and SUC2 is intact in snf3 delta hxt1 delta hxt2 delta hxt3 delta hxt4 delta hxt6 delta hxt7 delta gal2 cells, suggesting that the sensing and signaling mechanism for general glucose repression is independent from glucose uptake.

scholarly journals A G-protein alpha subunit from asexual Candida albicans functions in the mating signal transduction pathway of Saccharomyces cerevisiae and is regulated by the a1-alpha 2 repressor.

1992 ◽  
Vol 12 (5) ◽  
pp. 1977-1985 ◽  
Author(s):  
C Sadhu ◽  
D Hoekstra ◽  
M J McEachern ◽  
S I Reed ◽  
J B Hicks
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Signal Transduction ◽  
Candida Albicans ◽  
G Protein ◽  
Signal Transduction Pathway ◽  
Alpha Subunit ◽  
Transduction Pathway ◽  
G Protein Alpha Subunit ◽  
Protein Alpha Subunit ◽  
Null Mutants

We have isolated a gene, designated CAG1, from Candida albicans by using the G-protein alpha-subunit clone SCG1 of Saccharomyces cerevisiae as a probe. Amino acid sequence comparison revealed that CAG1 is more homologous to SCG1 than to any other G protein reported so far. Homology between CAG1 and SCG1 not only includes the conserved guanine nucleotide binding domains but also spans the normally variable regions which are thought to be involved in interaction with the components of the specific signal transduction pathway. Furthermore, CAG1 contains a central domain, previously found only in SCG1. cag1 null mutants of C. albicans created by gene disruption produced no readily detectable phenotype. The C. albicans CAG1 gene complemented both the growth and mating defects of S. cerevisiae scg1 null mutants when carried on either a low- or high-copy-number plasmid. In diploid C. albicans, the CAG1 transcript was readily detectable in mycelial and yeast cells of both the white and opaque forms. However, the CAG1-specific transcript in S. cerevisiae transformants containing the C. albicans CAG1 gene was observed only in haploid cells. This transcription pattern matches that of SCG1 in S. cerevisiae and is caused by a1-alpha 2 mediated repression in diploid cells. That is, CAG1 behaves as a haploid-specific gene in S. cerevisiae, subject to control by the a1-alpha 2 mating-type regulation pathway. We infer from these results that C. albicans may have a signal transduction system analogous to that controlling mating type in S. cerevisiae or possibly even a sexual pathway that has so far remained undetected.

scholarly journals A Genetic Study of Signaling Processes for Repression of PHO5 Transcription in Saccharomyces cerevisiae

Genetics ◽  
1998 ◽  
Vol 150 (4) ◽  
pp. 1349-1359 ◽  
Author(s):  
W-T Walter Lau ◽  
Ken R Schneider ◽  
Erin K O’Shea
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Signal Transduction ◽  
Constitutive Expression ◽  
Signal Transduction Pathway ◽  
Acid Synthesis ◽  
Phosphate Transport ◽  
Transduction Pathway ◽  
Plasma Membrane Atpase ◽  
Yeast Saccharomyces Cerevisiae

Abstract In the yeast Saccharomyces cerevisiae, transcription of a secreted acid phosphatase, PHO5, is repressed in response to high concentrations of extracellular inorganic phosphate. To investigate the signal transduction pathway leading to transcriptional regulation of PHO5, we carried out a genetic selection for mutants that express PHO5 constitutively. We then screened for mutants whose phenotypes are also dependent on the function of PHO81, which encodes an inhibitor of the Pho80p-Pho85p cyclin/cyclin-dependent kinase complex. These mutations are therefore likely to impair upstream functions in the signaling pathway, and they define five complementation groups. Mutations were found in a gene encoding a plasma membrane ATPase (PMA1), in genes required for the in vivo function of the phosphate transport system (PHO84 and PHO86), in a gene involved in the fatty acid synthesis pathway (ACC1), and in a novel, nonessential gene (PHO23). These mutants can be classified into two groups: pho84, pho86, and pma1 are defective in high-affinity phosphate uptake, whereas acc1 and pho23 are not, indicating that the two groups of mutations cause constitutive expression of PHO5 by distinct mechanisms. Our observations suggest that these gene products affect different aspects of the signal transduction pathway for PHO5 repression.

scholarly journals Isolation of Degradation-Deficient Mutants Defective in the Targeting of Fructose-1,6-bisphosphatase into the Vacuole for Degradation in Saccharomyces cerevisiae

Genetics ◽  
1996 ◽  
Vol 143 (4) ◽  
pp. 1555-1566 ◽  
Author(s):  
Mark Hoffman ◽  
Hui-Ling Chiang
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Signal Transduction ◽  
Carbon Source ◽  
Signal Transduction Pathway ◽  
Degradation Pathway ◽  
Transduction Pathway ◽  
Fructose 1,6 Bisphosphatase ◽  
Dependent Signal ◽  
Complementation Groups ◽  
Vacuolar Sorting

Abstract The key regulatory enzyme in the gluconeogenesis pathway, fructose-1,6-bisphosphatase (FBPase), is induced when Saccharomyces cerevisiae are grown in medium containing a poor carbon source. FBPase is targeted to the yeast vacuole for degradation when glucose-starved cells are replenished with fresh glucose. To identify genes involved in the FBPase degradation pathway, mutants that failed to degrade FBPase in response to glucose were isolated using a colony-blotting procedure. These vacuolar import and degradation-deficient (vid) mutants were placed into 20 complementation groups. They are distinct from the known sec, ups or pep mutants affecting protein secretion, vacuolar sorting and vacuolar proteolysis in that they sort CpY correctly and regulate osmotic pressure normally. Despite the presence of FBPase antigen in these mutants, FBPase is completely inactivated in all uid mutants, indicating that the c-AMP-dependent signal transduction pathway and inactivation must function properly in vid mutants. vid mutants block FBPase dzgradation by accumulating FBPase in the cytosol and also in small vesicles in the cytoplasm. FBPase may be targeted to small vesicles before uptake by the vacuole.

Glucose as a hormone: receptor-mediated glucose sensing in the yeast Saccharomyces cerevisiae

2005 ◽  
Vol 33 (1) ◽  
pp. 247-252 ◽  
Author(s):  
M. Johnston ◽  
J.-H. Kim
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Signal Transduction ◽  
Signal Transduction Pathway ◽  
Glucose Transporters ◽  
Glucose Sensing ◽  
Yeast Cells ◽  
Transduction Pathway ◽  
Yeast Saccharomyces Cerevisiae ◽  
Expression Of Genes ◽  
Genes Encoding

Because glucose is the principal carbon and energy source for most cells, most organisms have evolved numerous and sophisticated mechanisms for sensing glucose and responding to it appropriately. This is especially apparent in the yeast Saccharomyces cerevisiae, where these regulatory mechanisms determine the distinctive fermentative metabolism of yeast, a lifestyle it shares with many kinds of tumour cells. Because energy generation by fermentation of glucose is inefficient, yeast cells must vigorously metabolize glucose. They do this, in part, by carefully regulating the first, rate-limiting step of glucose utilization: its transport. Yeast cells have learned how to sense the amount of glucose that is available and respond by expressing the most appropriate of its 17 glucose transporters. They do this through a signal transduction pathway that begins at the cell surface with the Snf3 and Rgt2 glucose sensors and ends in the nucleus with the Rgt1 transcription factor that regulates expression of genes encoding glucose transporters. We explain this glucose signal transduction pathway, and describe how it fits into a highly interconnected regulatory network of glucose sensing pathways that probably evolved to ensure rapid and sensitive response of the cell to changing levels of glucose.

A G-protein alpha subunit from asexual Candida albicans functions in the mating signal transduction pathway of Saccharomyces cerevisiae and is regulated by the a1-alpha 2 repressor

1992 ◽  
Vol 12 (5) ◽  
pp. 1977-1985
Author(s):  
C Sadhu ◽  
D Hoekstra ◽  
M J McEachern ◽  
S I Reed ◽  
J B Hicks
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Signal Transduction ◽  
Candida Albicans ◽  
G Protein ◽  
Signal Transduction Pathway ◽  
Alpha Subunit ◽  
Transduction Pathway ◽  
G Protein Alpha Subunit ◽  
Protein Alpha Subunit ◽  
Null Mutants

We have isolated a gene, designated CAG1, from Candida albicans by using the G-protein alpha-subunit clone SCG1 of Saccharomyces cerevisiae as a probe. Amino acid sequence comparison revealed that CAG1 is more homologous to SCG1 than to any other G protein reported so far. Homology between CAG1 and SCG1 not only includes the conserved guanine nucleotide binding domains but also spans the normally variable regions which are thought to be involved in interaction with the components of the specific signal transduction pathway. Furthermore, CAG1 contains a central domain, previously found only in SCG1. cag1 null mutants of C. albicans created by gene disruption produced no readily detectable phenotype. The C. albicans CAG1 gene complemented both the growth and mating defects of S. cerevisiae scg1 null mutants when carried on either a low- or high-copy-number plasmid. In diploid C. albicans, the CAG1 transcript was readily detectable in mycelial and yeast cells of both the white and opaque forms. However, the CAG1-specific transcript in S. cerevisiae transformants containing the C. albicans CAG1 gene was observed only in haploid cells. This transcription pattern matches that of SCG1 in S. cerevisiae and is caused by a1-alpha 2 mediated repression in diploid cells. That is, CAG1 behaves as a haploid-specific gene in S. cerevisiae, subject to control by the a1-alpha 2 mating-type regulation pathway. We infer from these results that C. albicans may have a signal transduction system analogous to that controlling mating type in S. cerevisiae or possibly even a sexual pathway that has so far remained undetected.

scholarly journals Function of the ste signal transduction pathway for mating pheromones sustains MAT alpha 1 transcription in Saccharomyces cerevisiae.

1993 ◽  
Vol 13 (4) ◽  
pp. 2050-2060 ◽  
Author(s):  
Y Mukai ◽  
S Harashima ◽  
Y Oshima
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Signal Transduction ◽  
Signal Transduction Pathway ◽  
Single Copy ◽  
Upstream Region ◽  
Transduction Pathway ◽  
Mating Ability ◽  
Mating Pheromones ◽  
C Terminus ◽  
Dependent Protein

Sterile mutants of Saccharomyces cerevisiae were isolated from alpha * cells having the a/alpha aar1-6 genotype (exhibiting alpha mating ability and weak a mating ability as a result of a defect in a1-alpha 2 repression). Among these sterile mutants, we found two ste5 mutants together with putative ste7, ste11, and ste12 mutants of the signal transduction pathway of mating pheromones. The amino acid sequence of the Ste5p protein predicted from the nucleotide sequence of a cloned STE5 DNA has a domain rich in acidic amino acids close to its C terminus, a cysteine-rich sequence, resembling part of a zinc finger structure, in its N-terminal half, and a possible target site of cyclic AMP-dependent protein kinase at its C terminus. Northern (RNA) blot analysis revealed that STE5 transcription is under a1-alpha 2-Aar1p repression. The MAT alpha 1 cistron has a single copy of the pheromone response element in its 5' upstream region, and its basal level of transcription was reduced in these ste mutant cells. However, expression of the MAT alpha 1 cistron was not enhanced appreciably by pheromone signals. One of the ste5 mutant alleles conferred a sterile phenotype to a/alpha aar1-6 cells but a mating ability to MATa cells.

Sign in / Sign up

Export Citation Format

Share Document