Differential transmission of G1 cell cycle arrest and mating signals by Saccharomyces cerevisiae Ste5 mutants in the pheromone pathway.
Saccharomyces cerevisiae Ste5 is a scaffold protein that recruits many pheromone signaling molecules to sequester the pheromone pathway from other homologous mitogen-activated protein kinase pathways. G1 cell cycle arrest and mating are two different physiological consequences of pheromone signal transduction and Ste5 is required for both processes. However, the roles of Ste5 in G1 arrest and mating are not fully understood. To understand the roles of Ste5 better, we isolated 150 G1 cell cycle arrest defective STE5 mutants by chemical mutagenesis of the gene. Here, we found that two G1 cell cycle arrest defective STE5 mutants (ste5M(D248V) and ste5(delta-776)) retained mating capacity. When overproduced in a wild-type strain, several ste5 mutants also showed different dominant phenotypes for G1 arrest and mating. Isolation and characterization of the mutants suggested separable roles of Ste5 in G1 arrest and mating of S. cerevisiae. In addition, the roles of Asp-248 and Tyr-421, which are important for pheromone signal transduction were further characterized by site-directed mutagenesis studies.
Choi
Y J
YJ
Department of Biochemistry and Molecular Biology, Institute of Genetic Sciences, Yonsei University College of Medicine, Seoul, Korea.
Kim
S H
SH
Park
K S
KS
Choi
K Y
KY
D048868:Adaptor Proteins, Signal Transducing; D019943:Amino Acid Substitution; D002352:Carrier Proteins; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D016193:G1 Phase / Q000502:physiology*; D000072235:Mating Factor; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D016296:Mutagenesis; D016297:Mutagenesis, Site-Directed; D010455:Peptides / Q000494:pharmacology / Q000502:physiology*; D010675:Pheromones / Q000494:pharmacology / Q000502:physiology*; D010957:Plasmids / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction; D020798:Two-Hybrid System Techniques
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D005656:Fungal Proteins; D010455:Peptides; D010675:Pheromones; C080321:STE5 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D000072235:Mating Factor; D020929:Mitogen-Activated Protein Kinase Kinases