Role of a G Protein Homolog in Yeast Pheromone Response
The recent discovery of a G protein homolog involved in a yeast signal transduction system indicates that G proteins are conserved over a wide evolutionary distance (Dietzel and Kurjan, 1987; Nakafuku et al., 1987; Miyajima et al., 1987; Jahng et al., 1988). The extensive genetic characterization possible in yeast allows a type of approach to the study of G proteins not possible in vertebrate systems. Using such a genetic approach, we isolated theSCG1 gene, which encodes a homolog to the a subunits of G proteins. Genetic results have also provided evidence thatSCG1 is involved in pheromone response in yeast. Recently, putative homologs to the vertebrate ß and γ subunits have also been identified (M. Whiteway, personal communication). In this paper, after presenting background information on pheromone response, I will describe the isolation and characterization ofSCG1 and will discuss our currently favored model of the mechanism of action ofSCG1 in the pheromone response pathway.
KeywordsSaccharomyces Cerevisiae Carboxy Terminus Disruption Mutation Pheromone Receptor Pheromone Response
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