title: Concerted action of RAS and G proteins in the sexual response pathways of Schizosaccharomyces pombe.
abstract: We have shown that the expression of mam2, the gene encoding the Schizosaccharomyces pombe P-factor pheromone receptor, is dependent upon components of the pheromone signal transduction pathway, including Ras1, Gpa1, Byr1 and Byr2, each of which is required for both conjugation and sporulation. Studies of the expression of mam2 in mutant S. pombe cells confirm previous conclusions, based on the ability of cells to sporulate, that the Byr1 protein kinase acts downstream of the Byr2 protein kinase and that both act downstream of Ras1, the S. pombe RAS homolog, and Gpa1, the G alpha component that mediates the occupancy of the mam2 receptor. In addition, our present studies show that Ras1 and Gpa1 each act downstream from the other and hence act in concert. The Spk1 kinase, which is required for conjugation and sporulation and which is a structural and functional homolog of the vertebrate MAP kinases, is not required for mam2 expression.
authors.affiliation: Cold Spring Harbor Laboratory, New York 11724.
authors.forename: H P
authors.initials: HP
authors.lastname: Xu
authors.forename: M
authors.initials: M
authors.lastname: White
authors.forename: S
authors.initials: S
authors.lastname: Marcus
authors.forename: M
authors.initials: M
authors.lastname: Wigler
mesh_terms: D001483:Base Sequence; D003227:Conjugation, Genetic; D017931:DNA Primers / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D005656:Fungal Proteins / Q000378:metabolism*; D044385:GTP-Binding Protein alpha Subunits; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D019204:GTP-Binding Proteins / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D020962:Heterotrimeric GTP-Binding Proteins; D008969:Molecular Sequence Data; D011494:Protein Kinases / Q000378:metabolism; D051964:Receptors, Mating Factor; D018000:Receptors, Peptide / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins; D015398:Signal Transduction; D013172:Spores, Fungal / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors; D018631:ras Proteins
chemical_list: D017931:DNA Primers; D004271:DNA, Fungal; D005656:Fungal Proteins; D044385:GTP-Binding Protein alpha Subunits; D051964:Receptors, Mating Factor; D018000:Receptors, Peptide; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; D011494:Protein Kinases; C079509:byr1 protein kinase; D019204:GTP-Binding Proteins; C084293:GPA1 protein, S cerevisiae; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D020962:Heterotrimeric GTP-Binding Proteins; C489014:RAS1 protein, S cerevisiae; C492657:Ras1 protein, S pombe; D018631:ras Proteins