Dominant-negative mutants of a yeast G-protein beta subunit identify two functional regions involved in pheromone signalling.
The STE4 gene, which encodes the beta subunit of the mating response G-protein in the yeast Saccharomyces cerevisiae, was subjected to a saturation mutagenesis using 'doped' oligodeoxynucleotides. We employed a genetic screen to select dominant-negative STE4 mutants, which when overexpressed from the GAL1 promoter, interfered with the signalling function of the wild type protein. The identified inhibitory amino acid alterations define two small regions that are crucially involved in transmitting the mating signal from G beta to downstream components of the signalling pathway. These results underline the positive signalling role of yeast G beta and assign for the first time the positive signalling function of a G-protein beta subunit to specific structural features.
Leberer
E
E
Eukaryotic Genetics Group, National Research Council of Canada, Montreal, Quebec.
Dignard
D
D
Hougan
L
L
Thomas
D Y
DY
Whiteway
M
M
D000595:Amino Acid Sequence; D044387:GTP-Binding Protein beta Subunits; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005799:Genes, Dominant; D020962:Heterotrimeric GTP-Binding Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D010675:Pheromones / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins
D044387:GTP-Binding Protein beta Subunits; D010675:Pheromones; D029701:Saccharomyces cerevisiae Proteins; C067576:Ste4 protein, S cerevisiae; D019204:GTP-Binding Proteins; D020962:Heterotrimeric GTP-Binding Proteins