G protein mutations that alter the pheromone response in Saccharomyces cerevisiae.

The GPA1 gene of Saccharomyces cerevisiae encodes a G alpha protein that couples the membrane-bound pheromone receptors to downstream elements in the mating response pathway. We have isolated seven mutant alleles of GPA1 that confer pheromone resistance: G50D (a glycine-to-aspartate change at position 50), G322E, G322R, E355K, E364K, G470D, and an E364K-G470D double mutant. All of the mutations lie within large regions that are highly conserved between Gpa1 and four other G alpha proteins; four of the changes are located in domains with proposed functions. On the basis of a gentic analysis, the pheromone-unresponsive GPA1 alleles can be divided into two classes: those that encode constitutively activated proteins and those that encode proteins unable to respond to the upstream signal. Our results support the hypothesis that the activated form of Gpa1 stimulates adaptation to pheromone.

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Mot3, a Zn Finger Transcription Factor That Modulates Gene Expression and Attenuates Mating Pheromone Signaling in Saccharomyces cerevisiae

Genetics ◽

10.1093/genetics/149.2.879 ◽

1998 ◽

Vol 149 (2) ◽

pp. 879-892 ◽

Cited By ~ 1

Author(s):

Anatoly V Grishin ◽

Michael Rothenberg ◽

Maureen A Downs ◽

Kendall J Blumer

Keyword(s):

Gene Expression ◽

Saccharomyces Cerevisiae ◽

Signaling Pathway ◽

G Protein ◽

Binding Sites ◽

Dependent Manner ◽

Pheromone Response ◽

Mating Pheromone ◽

Pheromone Signaling ◽

Yeast Genes

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.

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SST2, a Regulator of G-Protein Signaling for the Candida albicans Mating Response Pathway

Eukaryotic Cell ◽

10.1128/ec.5.1.192-202.2006 ◽

2006 ◽

Vol 5 (1) ◽

pp. 192-202 ◽

Cited By ~ 30

Author(s):

Daniel Dignard ◽

Malcolm Whiteway

Keyword(s):

Saccharomyces Cerevisiae ◽

Candida Albicans ◽

G Protein ◽

Sequence Similarity ◽

Transcriptional Profiling ◽

Protein Signaling ◽

Mating Response ◽

Cycle Arrest ◽

Strain Sc5314 ◽

Regulated Gene Expression

ABSTRACT Candida albicans contains a functional mating response pathway that is similar to the well-studied system of Saccharomyces cerevisiae. We have characterized a regulator of G protein signaling (RGS) homolog in C. albicans with sequence similarity to the SST2 gene of Saccharomyces cerevisiae. Disruption of this gene, which had been designated SST2, causes an opaque MTL a/MTL a derivative of strain SC5314 to show hypersensitivity to the C. albicans α-factor. This hypersensitivity generates an enhanced cell cycle arrest detected in halo assays but reduces the overall mating efficiency of the cells. Transcriptional profiling of the pheromone-regulated gene expression in the sst2 mutant shows a pattern of gene induction similar to that observed in wild-type cells, but the responsiveness is heightened. This involvement of an RGS in the sensitivity to pheromone is consistent with the prediction that the mating response pathway in C. albicans requires the activation of a heterotrimeric G protein.

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Mutations in cell division cycle genes CDC36 and CDC39 activate the Saccharomyces cerevisiae mating pheromone response pathway

Molecular and Cellular Biology ◽

10.1128/mcb.10.6.2966-2972.1990 ◽

1990 ◽

Vol 10 (6) ◽

pp. 2966-2972

Author(s):

M de Barros Lopes ◽

J Y Ho ◽

S I Reed

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Cycle ◽

G Protein ◽

G1 Arrest ◽

Restrictive Temperature ◽

Gene Products ◽

Pheromone Response ◽

Mating Pheromone ◽

Pheromone Response Pathway ◽

Mutational Activation

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.

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Overexpression of the STE4 gene leads to mating response in haploid Saccharomyces cerevisiae

Molecular and Cellular Biology ◽

10.1128/mcb.10.1.217-222.1990 ◽

1990 ◽

Vol 10 (1) ◽

pp. 217-222

Author(s):

M Whiteway ◽

L Hougan ◽

D Y Thomas

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Cycle ◽

Cell Cycle Arrest ◽

G Protein ◽

Gene Product ◽

Beta Subunit ◽

Yeast Cells ◽

Pheromone Response ◽

Mating Pheromone ◽

Cycle Arrest

The STE4 gene of Saccharomyces cerevisiae encodes the beta subunit of the yeast pheromone receptor-coupled G protein. Overexpression of the STE4 protein led to cell cycle arrest of haploid cells. This arrest was like the arrest mediated by mating pheromones in that it led to similar morphological changes in the arrested cells. The arrest occurred in haploid cells of either mating type but not in MATa/MAT alpha diploids, and it was suppressed by defects in genes such as STE12 that are needed for pheromone response. Overexpression of the STE4 gene product also suppressed the sterility of cells defective in the mating pheromone receptors encoded by the STE2 and STE3 genes. Cell cycle arrest mediated by STE4 overexpression was prevented in cells that either were overexpressing the SCG1 gene product (the alpha subunit of the G protein) or lacked the STE18 gene product (the gamma subunit of the G protein). This finding suggests that in yeast cells, the beta subunit is the limiting component of the active beta gamma element and that a proper balance in the levels of the G-protein subunits is critical to a normal mating pheromone response.

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Overexpression of the STE4 gene leads to mating response in haploid Saccharomyces cerevisiae.

Molecular and Cellular Biology ◽

10.1128/mcb.10.1.217 ◽

1990 ◽

Vol 10 (1) ◽

pp. 217-222 ◽

Cited By ~ 84

Author(s):

M Whiteway ◽

L Hougan ◽

D Y Thomas

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Cycle ◽

Cell Cycle Arrest ◽

G Protein ◽

Gene Product ◽

Beta Subunit ◽

Yeast Cells ◽

Pheromone Response ◽

Mating Pheromone ◽

Cycle Arrest

The STE4 gene of Saccharomyces cerevisiae encodes the beta subunit of the yeast pheromone receptor-coupled G protein. Overexpression of the STE4 protein led to cell cycle arrest of haploid cells. This arrest was like the arrest mediated by mating pheromones in that it led to similar morphological changes in the arrested cells. The arrest occurred in haploid cells of either mating type but not in MATa/MAT alpha diploids, and it was suppressed by defects in genes such as STE12 that are needed for pheromone response. Overexpression of the STE4 gene product also suppressed the sterility of cells defective in the mating pheromone receptors encoded by the STE2 and STE3 genes. Cell cycle arrest mediated by STE4 overexpression was prevented in cells that either were overexpressing the SCG1 gene product (the alpha subunit of the G protein) or lacked the STE18 gene product (the gamma subunit of the G protein). This finding suggests that in yeast cells, the beta subunit is the limiting component of the active beta gamma element and that a proper balance in the levels of the G-protein subunits is critical to a normal mating pheromone response.

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Specific -Arrestins Negatively Regulate Saccharomyces cerevisiae Pheromone Response by Down-Modulating the G-Protein-Coupled Receptor Ste2

Molecular and Cellular Biology ◽

10.1128/mcb.00230-14 ◽

2014 ◽

Vol 34 (14) ◽

pp. 2660-2681 ◽

Cited By ~ 65

Author(s):

C. G. Alvaro ◽

A. F. O'Donnell ◽

D. C. Prosser ◽

A. A. Augustine ◽

A. Goldman ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

G Protein ◽

Pheromone Response ◽

G Protein Coupled Receptor ◽

G Protein Coupled

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The plasma membrane ferrireductase activity of Saccharomyces cerevisiae is partially controlled by cyclic AMP

Biochemical Journal ◽

10.1042/bj2800545 ◽

1991 ◽

Vol 280 (2) ◽

pp. 545-548 ◽

Cited By ~ 24

Author(s):

E Lesuisse ◽

B Horion ◽

P Labbe ◽

F Hilger

Keyword(s):

Saccharomyces Cerevisiae ◽

Plasma Membrane ◽

Cyclic Amp ◽

Double Mutant ◽

Synthetic Medium ◽

Iron Limitation ◽

Permissive Temperature ◽

Extract Content ◽

Dependent Protein ◽

Membrane Bound

The plasma-membrane-bound ferrireductase activity of ras1 and ras2 mutants of Saccharomyces cerevisiae is not induced in response to iron limitation. This phenotype was suppressed by the bcy1 mutation in ras2 but not in ras1 mutants. The cellular haem content of ras-1-bearing strains decreased dramatically when cells were grown in semi-synthetic medium (low yeast extract content), which could account for their very low ferrireductase activity. The ferrireductase activity of cdc25 and cdc35 mutants dropped when the cells were shifted to a non-permissive temperature. This drop was prevented in the double mutant cdc35 sra5 by adding cyclic AMP to the growth medium. We propose that ferrireductase activity is under the control of a cyclic AMP-dependent protein phosphorylation.

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Mutations in cell division cycle genes CDC36 and CDC39 activate the Saccharomyces cerevisiae mating pheromone response pathway.

Molecular and Cellular Biology ◽

10.1128/mcb.10.6.2966 ◽

1990 ◽

Vol 10 (6) ◽

pp. 2966-2972 ◽

Cited By ~ 18

Author(s):

M de Barros Lopes ◽

J Y Ho ◽

S I Reed

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Cycle ◽

G Protein ◽

G1 Arrest ◽

Restrictive Temperature ◽

Gene Products ◽

Pheromone Response ◽

Mating Pheromone ◽

Pheromone Response Pathway ◽

Mutational Activation

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.

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Degradation of a-factor by a Saccharomyces cerevisiae alpha-mating-type-specific endopeptidase: evidence for a role in recovery of cells from G1 arrest.

Molecular and Cellular Biology ◽

10.1128/mcb.11.2.1030 ◽

1991 ◽

Vol 11 (2) ◽

pp. 1030-1039 ◽

Cited By ~ 19

Author(s):

S Marcus ◽

C B Xue ◽

F Naider ◽

J M Becker

Keyword(s):

Saccharomyces Cerevisiae ◽

Mating Type ◽

Morphological Alteration ◽

G1 Arrest ◽

Alpha Cells ◽

Phenylmethylsulfonyl Fluoride ◽

Pheromone Response ◽

Mating Response ◽

Time Required ◽

Energy Dependent

Mating response between opposite mating types of Saccharomyces cerevisiae is dependent upon alpha factor, a tridecapeptide, and a-factor, an isoprenylated, methyl esterified dodecapeptide whose interaction with the alpha target cell has not been characterized. We report on the first biochemical and physiological evidence of an alpha-mating-type-specific a-factor-degrading activity. Radioiodinated a-factor was used to identify the a-factor-degrading activity, which is cell associated, endoproteolytic, and not required for response to pheromone. a-factor degradation was not energy dependent, nor did it require pheromone internalization or interaction with its receptor. Phenylmethylsulfonyl fluoride and tosyl-L-arginyl-methyl ester inhibited degradation of a-factor and increased the time required by alpha cells to recover from a-factor-induced growth arrest and morphological alteration, providing evidence that a-factor degradation plays a role in the recovery of alpha cells from the pheromone response.

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