Signal Propagation and Regulation in the Mating Pheromone Response Pathway of the Yeast Saccharomyces cerevisiae

1994 ◽  
Vol 166 (2) ◽  
pp. 363-379 ◽  
Author(s):  
Lee Bardwell ◽  
Jeanette G. Cook ◽  
Carla J. Inouye ◽  
Jeremy Thorner
2000 ◽  
Vol 25 (2) ◽  
pp. 125-131 ◽  
Author(s):  
Junko Nakajima-Shimada ◽  
Shuichi Sakaguchi ◽  
Frederick I. Tsuji ◽  
Yasuhiro Anraku ◽  
Hidetoshi Iida

1990 ◽  
Vol 10 (6) ◽  
pp. 2966-2972
Author(s):  
M de Barros Lopes ◽  
J Y Ho ◽  
S I Reed

Conditional mutations in the genes CDC36 and CDC39 cause arrest in the G1 phase of the Saccharomyces cerevisiae cell cycle at the restrictive temperature. We present evidence that this arrest is a consequence of a mutational activation of the mating pheromone response. cdc36 and cdc39 mutants expressed pheromone-inducible genes in the absence of pheromone and conjugated in the absence of a mating pheromone receptor. On the other hand, cells lacking the G beta subunit or overproducing the G alpha subunit of the transducing G protein that couples the receptor to the pheromone response pathway prevented constitutive activation of the pathway in cdc36 and cdc39 mutants. These epistasis relationships imply that the CDC36 and CDC39 gene products act at the level of the transducing G protein. The CDC36 and CDC39 gene products have a role in cellular processes other than the mating pheromone response. A mating-type heterozygous diploid cell, homozygous for either the cdc36 or cdc39 mutation, does not exhibit the G1 arrest phenotype but arrests asynchronously with respect to the cell cycle. A similar asynchronous arrest was observed in cdc36 and cdc39 cells where the pheromone response pathway had been inactivated by mutations in the transducing G protein. Furthermore, cdc36 and cdc39 mutants, when grown on carbon catabolite-derepressing medium, did not arrest in G1 and did not induce pheromone-specific genes at the restrictive temperature.


1990 ◽  
Vol 10 (6) ◽  
pp. 2966-2972 ◽  
Author(s):  
M de Barros Lopes ◽  
J Y Ho ◽  
S I Reed

Conditional mutations in the genes CDC36 and CDC39 cause arrest in the G1 phase of the Saccharomyces cerevisiae cell cycle at the restrictive temperature. We present evidence that this arrest is a consequence of a mutational activation of the mating pheromone response. cdc36 and cdc39 mutants expressed pheromone-inducible genes in the absence of pheromone and conjugated in the absence of a mating pheromone receptor. On the other hand, cells lacking the G beta subunit or overproducing the G alpha subunit of the transducing G protein that couples the receptor to the pheromone response pathway prevented constitutive activation of the pathway in cdc36 and cdc39 mutants. These epistasis relationships imply that the CDC36 and CDC39 gene products act at the level of the transducing G protein. The CDC36 and CDC39 gene products have a role in cellular processes other than the mating pheromone response. A mating-type heterozygous diploid cell, homozygous for either the cdc36 or cdc39 mutation, does not exhibit the G1 arrest phenotype but arrests asynchronously with respect to the cell cycle. A similar asynchronous arrest was observed in cdc36 and cdc39 cells where the pheromone response pathway had been inactivated by mutations in the transducing G protein. Furthermore, cdc36 and cdc39 mutants, when grown on carbon catabolite-derepressing medium, did not arrest in G1 and did not induce pheromone-specific genes at the restrictive temperature.


Genetics ◽  
1998 ◽  
Vol 149 (2) ◽  
pp. 879-892 ◽  
Author(s):  
Anatoly V Grishin ◽  
Michael Rothenberg ◽  
Maureen A Downs ◽  
Kendall J Blumer

Abstract In the yeast Saccharomyces cerevisiae, mating pheromone response is initiated by activation of a G protein- and mitogen-activated protein (MAP) kinase-dependent signaling pathway and attenuated by several mechanisms that promote adaptation or desensitization. To identify genes whose products negatively regulate pheromone signaling, we screened for mutations that suppress the hyperadaptive phenotype of wild-type cells overexpressing signaling-defective G protein β subunits. This identified recessive mutations in MOT3, which encodes a nuclear protein with two Cys2-His2 Zn fingers. MOT3 was found to be a dosage-dependent inhibitor of pheromone response and pheromone-induced gene expression and to require an intact signaling pathway to exert its effects. Several results suggested that Mot3 attenuates expression of pheromone-responsive genes by mechanisms distinct from those used by the negative transcriptional regulators Cdc36, Cdc39, and Mot2. First, a Mot3-lexA fusion functions as a transcriptional activator. Second, Mot3 is a dose-dependent activator of several genes unrelated to pheromone response, including CYC1, SUC2, and LEU2. Third, insertion of consensus Mot3 binding sites (C/A/T)AGG(T/C)A activates a promoter in a MOT3-dependent manner. These findings, and the fact that consensus binding sites are found in the 5′ flanking regions of many yeast genes, suggest that Mot3 is a globally acting transcriptional regulator. We hypothesize that Mot3 regulates expression of factors that attenuate signaling by the pheromone response pathway.


1993 ◽  
Vol 13 (6) ◽  
pp. 3765-3772
Author(s):  
C Kirkman-Correia ◽  
I L Stroke ◽  
S Fields

The pheromone response pathway of the yeast Saccharomyces cerevisiae is necessary for the basal level of transcription of cell-type-specific genes, as well as the induced level observed after pheromone treatment. The STE12 protein binds to the DNA sequence designated the pheromone response element and is a target of the pheromone-induced signal. We generated 6-nucleotide linker insertion mutants, internal-deletion mutants, and carboxy-terminal truncation mutants of STE12 and assayed them for their ability to restore mating and transcriptional activity to a ste12 delta strain. Two of these mutant proteins retain the capacity to mediate basal transcription but show little or no induced transcription upon pheromone treatment. Cells producing these proteins cannot mate, formally demonstrating that the ability to respond to pheromone by increasing gene expression is essential for the mating process. Since distinct domains of STE12 appear to be required for basal versus induced transcription, we suggest that the pheromone-induced signal is likely to target residues of the protein different from those targeted by the basal signal because of the constitutive activity of the response pathway. Our analysis of mutant STE12 proteins also indicates that only the DNA-binding domain is sensitive to the small changes caused by the linker insertions. In addition, we show that, while the carboxy-terminal sequences necessary for STE12 to form a complex with the transcription factor MCM1 are not essential for mating, these sequences are required for optimal transcriptional activity.


1993 ◽  
Vol 120 (5) ◽  
pp. 1203-1215 ◽  
Author(s):  
K Kuchler ◽  
H G Dohlman ◽  
J Thorner

STE6 gene product is required for secretion of the lipopeptide mating pheromone a-factor by Saccharomyces cerevisiae MATa cells. Radiolabeling and immunoprecipitation, either with specific polyclonal antibodies raised against a TrpE-Ste6 fusion protein or with mAbs that recognize c-myc epitopes in fully functional epitope-tagged Ste6 derivatives, demonstrated that Ste6 is a 145-kD phosphoprotein. Subcellular fractionation, various extraction procedures, and immunoblotting showed that Ste6 is an intrinsic plasma membrane-associated protein. The apparent molecular weight of Ste6 was unaffected by tunicamycin treatment, and the radiolabeled protein did not bind to concanavalin A, indicating that Ste6 is not glycosylated and that glycosylation is not required either for its membrane delivery or its function. The amino acid sequence of Ste6 predicts two ATP-binding folds; correspondingly, Ste6 was photoaffinity-labeled specifically with 8-azido-[alpha-32P]ATP. Indirect immunofluorescence revealed that in exponentially growing MATa cells, the majority of Ste6 showed a patchy distribution within the plasma membrane, but a significant fraction was found concentrated in a number of vesicle-like bodies subtending the plasma membrane. In contrast, in MATa cells exposed to the mating pheromone alpha-factor, which markedly induced Ste6 production, the majority of Ste6 was incorporated into the plasma membrane within the growing tip of the elongating cells. The highly localized insertion of this transporter may establish pronounced anisotropy in a-factor secretion from the MATa cell, and thereby may contribute to the establishment of the cell polarity which restricts partner selection and cell fusion during mating to one MAT alpha cell.


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