Two recessive mutations in the Saccharomyces cerevisiae SIG1 (suppressor of inhibitory G-protein) gene have been identified by their ability to suppress the signalling defect of dominant-negative variants of the mating response G-protein beta-subunit. The mutations and deletion of SIG1 enhance the sensitivity of the cells to pheromone and stimulate the basal transcription of a mating specific gene, FUS1, suggesting that Sig1p plays a negatively regulatory role in G beta gamma-mediated signal transduction. An additional function of Sig1p in vegetatively growing cells is suggested by the finding that the mutations and deletion of SIG1 cause temperature-sensitive growth defects. The SIG1 gene encodes a protein with a molecular weight of 65 kDa that contains at the amino-terminus two zinc finger-like sequence motifs. Epistasis experiments localize the action of Sig1p within the pheromone signalling pathway at a position at or shortly after the G-protein. We propose that Sig1p represents a novel negative regulator of G beta gamma-mediated signal transduction.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|