The yeast SCG1 gene: a G alpha-like protein implicated in the a- and alpha-factor response pathway

Cell. 1987 Sep 25;50(7):1001-10. doi: 10.1016/0092-8674(87)90166-8.


We have identified the SCG1 gene by its ability to suppress the pheromone-supersensitive sst2-1 mutation. The nucleotide sequence of SCG1 suggests that it encodes a 54 kd protein homologous to the alpha subunit of the vertebrate G proteins transducin, Gs, Gi, and Go. SCG1 expression and function are haploid-specific; haploid scg1 cells grow into very small colonies consisting of large, abnormally shaped cells, whereas a/alpha scg1/scg1 diploids show wild-type morphology, growth, and sporulation. We postulate that the SCG1 product is involved in the pheromone response pathway, and propose two models for the function of the SCG1 product. Expression of the rat alpha s gene in yeast partially complements both the sst2 and scg1 defects, indicating a high level of conservation of sequence and function between SCG1 and mammalian G alpha subunits.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Biological Evolution
  • Fungal Proteins / genetics*
  • Fungal Proteins / physiology
  • GTP-Binding Proteins / genetics*
  • GTP-Binding Proteins / physiology
  • Genes
  • Genes, Fungal*
  • Genetic Complementation Test
  • Mating Factor
  • Models, Biological
  • Peptides / physiology
  • Phenotype
  • Rats / genetics
  • Recombinant Fusion Proteins / physiology
  • Saccharomyces cerevisiae / genetics*
  • Sequence Homology, Nucleic Acid


  • Fungal Proteins
  • Peptides
  • Recombinant Fusion Proteins
  • Mating Factor
  • GTP-Binding Proteins

Associated data

  • GENBANK/M17414