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.

scholarly journals A RANK/TRAF6-dependent Signal Transduction Pathway Is Essential for Osteoclast Cytoskeletal Organization and Resorptive Function

2002 ◽  
Vol 277 (46) ◽  
pp. 44347-44356 ◽  
Author(s):  
Allison P. Armstrong ◽  
Mark E. Tometsko ◽  
Moira Glaccum ◽  
Claire L. Sutherland ◽  
David Cosman ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Signal Transduction Pathway ◽  
Transduction Pathway ◽  
Cytoskeletal Organization ◽  
Dependent Signal

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.

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