Pheromone response in the yeast Saccharomyces cerevisiae provides a microbial model for studying general features of hormone action and cell division control. When alpha-factor pheromone binds to specific receptors on the surface of yeast --a-- cells, it causes the cells to arrest division in the G1 phase of the cycle. The occupied receptors are continually internalized and resynthesized. After prolonged exposure to alpha-factor, the cells """"""""adapt"""""""" to the pheromone and reenter the mitotic cycle. Genetic studies suggest that the receptor belongs to the same structural class as rhodopsin and the beta- adrenergic receptor and that signal transduction is mediated by a heterotrimeric GTP-binding regulatory protein (G protein). Detailed understanding of this very basic process in yeast should provide information for a more general understanding of receptor action and cell division control. A combined genetic and biochemical approach will be applied to this problem. Structural features of the receptor which control its ligand binding, signal transduction, and ligand- mediated internalization activities will be identified by isolating and characterizing receptor mutants with specific defects in each of these properties. Factors which interact with the receptor to mediate signal transduction and receptor internalization will be defined genetically by isolating suppressors which compensate for each of the specific receptor defects. The fate of the receptor and G protein after alpha- factor stimulation will be determined. A purified in vitro assay for signal transduction will be developed in order to examine specific interactions among the receptor and the three G protein subunits and to determine the role that these interactions play in the adaptation process.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM034719-10
Application #
2177551
Study Section
Genetics Study Section (GEN)
Project Start
1985-04-01
Project End
1997-03-31
Budget Start
1994-04-01
Budget End
1995-03-31
Support Year
10
Fiscal Year
1994
Total Cost
Indirect Cost
Name
University of Massachusetts Medical School Worcester
Department
Genetics
Type
Schools of Medicine
DUNS #
660735098
City
Worcester
State
MA
Country
United States
Zip Code
01655
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Hirschman, J E; Jenness, D D (1999) Dual lipid modification of the yeast ggamma subunit Ste18p determines membrane localization of Gbetagamma. Mol Cell Biol 19:7705-11
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Hirschman, J E; De Zutter, G S; Simonds, W F et al. (1997) The G beta gamma complex of the yeast pheromone response pathway. Subcellular fractionation and protein-protein interactions. J Biol Chem 272:240-8
Bukusoglu, G; Jenness, D D (1996) Agonist-specific conformational changes in the yeast alpha-factor pheromone receptor. Mol Cell Biol 16:4818-23
Song, J; Hirschman, J; Gunn, K et al. (1996) Regulation of membrane and subunit interactions by N-myristoylation of a G protein alpha subunit in yeast. J Biol Chem 271:20273-83
Schandel, K A; Jenness, D D (1994) Direct evidence for ligand-induced internalization of the yeast alpha-factor pheromone receptor. Mol Cell Biol 14:7245-55
Hasson, M S; Blinder, D; Thorner, J et al. (1994) Mutational activation of the STE5 gene product bypasses the requirement for G protein beta and gamma subunits in the yeast pheromone response pathway. Mol Cell Biol 14:1054-65
Konopka, J B; Jenness, D D (1991) Genetic fine-structural analysis of the Saccharomyces cerevisiae alpha-pheromone receptor. Cell Regul 2:439-52

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