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- Title
Suppression of a dominant G protein β-subunit mutation in yeast by Gα protein expression.
- Authors
Meng Zhang; Tipper, Donald J.
- Abstract
<em>SCG1/GPA1, STE4</em>, and <em>STE18</em> encode the α, β and γ components of the G protein involved in mating pheromone signal transduction in <em>Saccharomyces cerevisiae</em>. Responses, including G1 arrest and expression of genes such as <em>FUS1</em>, are activated by βγ, which is negatively controlled by α(GDP). We previously demonstrated that overexpreesion of Scg1 suppresses responses to α factor and that expression of certain hybrids between Scg1 and mammalian Gα proteins has the same effect and also suppresses growth arrest in an <em>scg1</em>-null mutant. Effects were attributed to sequestration of βγ. We now show that effects on growth rate, morphology and <em>FUS1</em> expression are consistent with this model. The <em>STE4</em>HPL allele causes dominant activation of the response pathway, and is presumed to encode a β subunit insensitive to control by β(GDP). Scg1 overexpression suppresses the growth arrest due to <em>STE4</em>HPL; normal α-factor responses and fertility are restored. A model based on sequestration of βγ reconciles this result with the apparent paradox that the same level of Scg1 overexpression inhibits responses and mating in wild-type cells. A Gαi hybrid also restores growth and allows inefficient mating in the <em>STE4</em>HPL strain.
- Publication
Molecular Microbiology, 1993, Vol 9, Issue 4, p813
- ISSN
0950-382X
- Publication type
Academic Journal
- DOI
10.1111/j.1365-2958.1993.tb01740.x