title: Binding of alpha-factor pheromone to yeast a cells: chemical and genetic evidence for an alpha-factor receptor.
abstract: The division cycle of yeast a cells is inhibited by alpha-factor. Haploid a cells were found to bind 35S-labeled alpha-factor, whereas haploid alpha cells and diploid a/alpha cells showed little binding. The association of alpha-factor with a cells was reversible upon dilution. Unlabeled alpha-factor competed for binding of 35S-alpha-factor; the concentration dependence for competition indicated 9 X 10(5) binding sites per cell with a dissociation constant (KD) of 3 X 10(-7) M. The rates of association (kon = 3 X 10(3) M-1 sec-1) and dissociation (koff = 9 X 10(-4) sec-1) were consistent with the equilibrium constant. The alpha-factor binding activity associated with five temperature-sensitive ste2 mutants was thermolabile, suggesting that the STE2 gene encodes the receptor for alpha-factor. In contrast, the binding activity of other temperature-sensitive mutants (ste4, ste5, ste7, ste11, and ste12) showed no thermolability.
mesh_terms: D001665:Binding Sites; D005838:Genotype; D006238:Haploidy; D007700:Kinetics; D000072235:Mating Factor; D009154:Mutation; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D013045:Species Specificity; D013696:Temperature
chemical_list: D010455:Peptides; D000072235:Mating Factor