title: Induction of yeast mating pheromone a-factor by alpha cells.
abstract: Saccharomyces cerevisiae cells of a and alpha mating types constitutively secrete cell-specific peptide mating pheromones. a-Factor is secreted by a cells and acts on alpha cells, while alpha-factor is secreted by alpha cells and acts on a cells. Confirming preliminary studies, we demonstrate here that cultures of a cells contain higher than constitutive levels of a-factor activity when grown with alpha cells or alpha-factor. This induction of a-factor may result from increased synthesis or increased secretion of a-factor, as opposed to modification or stabilization of preexisting a-factor, as part of the a cell response to alpha-factor, as an a ste2 mutant (which cannot respond to alpha-factor) is not induced by alpha-factor. In mixed cultures inoculated with equal numbers of a cells and alpha cells, a cells predominate by stationary phase. Thus, a series of sequential interactions between a and alpha cells may be involved in establishing optimal hormone concentrations and cell ratios for conjugation.
mesh_terms: D000818:Animals; D002450:Cell Communication; D005656:Fungal Proteins / Q000096:biosynthesis; D000072235:Mating Factor; D010452:Peptide Biosynthesis; D010455:Peptides; D010675:Pheromones / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000502:physiology*
chemical_list: D005656:Fungal Proteins; D010455:Peptides; D010675:Pheromones; D000072235:Mating Factor