The DAC2/FUS3 protein kinase is not essential for transcriptional activation of the mating pheromone response pathway in Saccharomyces cerevisiae

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

Developmental Biology ◽

10.1006/dbio.1994.1323 ◽

1994 ◽

Vol 166 (2) ◽

pp. 363-379 ◽

Cited By ~ 99

Author(s):

Lee Bardwell ◽

Jeanette G. Cook ◽

Carla J. Inouye ◽

Jeremy Thorner

Keyword(s):

Saccharomyces Cerevisiae ◽

Signal Propagation ◽

Pheromone Response ◽

Mating Pheromone ◽

Yeast Saccharomyces Cerevisiae ◽

Pheromone Response Pathway

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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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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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A yeast mitogen-activated protein kinase homolog (Mpk1p) mediates signalling by protein kinase C

Molecular and Cellular Biology ◽

10.1128/mcb.13.5.3067-3075.1993 ◽

1993 ◽

Vol 13 (5) ◽

pp. 3067-3075 ◽

Cited By ~ 2

Author(s):

K S Lee ◽

K Irie ◽

Y Gotoh ◽

Y Watanabe ◽

H Araki ◽

...

Keyword(s):

Protein Kinase ◽

Map Kinase ◽

Protein Kinases ◽

Map Kinases ◽

Pheromone Response ◽

Pheromone Response Pathway ◽

Kinase C ◽

Mitogen Activated Protein ◽

Kinase Cascade ◽

Protein Kinase Cascade

Mitogen-activated protein (MAP) kinases are activated in response to a variety of stimuli through a protein kinase cascade that results in their phosphorylation on tyrosine and threonine residues. The molecular nature of this cascade is just beginning to emerge. Here we report the isolation of a Saccharomyces cerevisiae gene encoding a functional analog of mammalian MAP kinases, designated MPK1 (for MAP kinase). The MPK1 gene was isolated as a dosage-dependent suppressor of the cell lysis defect associated with deletion of the BCK1 gene. The BCK1 gene is also predicted to encode a protein kinase which has been proposed to function downstream of the protein kinase C isozyme encoded by PKC1. The MPK1 gene possesses a 1.5-kb uninterrupted open reading frame predicted to encode a 53-kDa protein. The predicted Mpk1 protein (Mpk1p) shares 48 to 50% sequence identity with Xenopus MAP kinase and with the yeast mating pheromone response pathway components, Fus3p and Kss1p. Deletion of MPK1 resulted in a temperature-dependent cell lysis defect that was virtually indistinguishable from that resulting from deletion of BCK1, suggesting that the protein kinases encoded by these genes function in a common pathway. Expression of Xenopus MAP kinase suppressed the defect associated with loss of MPK1 but not the mating-related defects associated with loss of FUS3 or KSS1, indicating functional conservation between the former two protein kinases. Mutation of the presumptive phosphorylated tyrosine and threonine residues of Mpk1p individually to phenylalanine and alanine, respectively, severely impaired Mpk1p function. Additional epistasis experiments, and the overall architectural similarity between the PKC1-mediated pathway and the pheromone response pathway, suggest that Pkc1p regulates a protein kinase cascade in which Bck1p activates a pair of protein kinases, designated Mkk1p and Mkk2p (for MAP kinase-kinase), which in turn activate Mpk1p.

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Glucose derepression of gluconeogenic enzymes in Saccharomyces cerevisiae correlates with phosphorylation of the gene activator Cat8p.

Molecular and Cellular Biology ◽

10.1128/mcb.17.5.2502 ◽

1997 ◽

Vol 17 (5) ◽

pp. 2502-2510 ◽

Cited By ~ 83

Author(s):

F Randez-Gil ◽

N Bojunga ◽

M Proft ◽

K D Entian

Keyword(s):

Saccharomyces Cerevisiae ◽

Protein Kinase ◽

Transcriptional Activation ◽

Phosphoenolpyruvate Carboxykinase ◽

Glucose Repression ◽

Sodium Dodecyl ◽

Binding Motif ◽

Gluconeogenic Enzymes ◽

Zinc Cluster ◽

Activating Function

The Cat8p zinc cluster protein is essential for growth of Saccharomyces cerevisiae with nonfermentable carbon sources. Expression of the CAT8 gene is subject to glucose repression mainly caused by Mig1p. Unexpectedly, the deletion of the Mig1p-binding motif within the CAT8 promoter did not increase CAT8 transcription; moreover, it resulted in a loss of CAT8 promoter activation. Insertion experiments with a promoter test plasmid confirmed that this regulatory 20-bp element influences glucose repression and derepression as well. This finding suggests an upstream activating function of this promoter region, which is Mig1p independent, as delta mig1 mutants are still able to derepress the CAT8 promoter. No other putative binding sites such as a Hap2/3/4/5p site and an Abf1p consensus site were functional with respect to glucose-regulated CAT8 expression. Fusions of Cat8p with the Gal4p DNA-binding domain mediated transcriptional activation. This activation capacity was still carbon source regulated and depended on the Cat1p (Snf1p) protein kinase, which indicated that Cat8p needs posttranslational modification to reveal its gene-activating function. Indeed, Western blot analysis on sodium dodecyl sulfate-gels revealed a single band (Cat8pI) with crude extracts from glucose-grown cells, whereas three bands (Cat8pI, -II, and -III) were identified in derepressed cells. Derepression-specific Cat8pII and -III resulted from differential phosphorylation, as shown by phosphatase treatment. Only the most extensively phosphorylated modification (Cat8pIII) depended on the Cat1p (Snf1p) kinase, indicating that another protein kinase is responsible for modification form Cat8pII. The occurrence of Cat8pIII was strongly correlated with the derepression of gluconeogenic enzymes (phosphoenolpyruvate carboxykinase and fructose-1,6-bisphosphatase) and gluconeogenic PCK1 mRNA. Furthermore, glucose triggered the dephosphorylation of Cat8pIII, but this did not depend on the Glc7p (Cid1p) phosphatase previously described as being involved in invertase repression. These results confirm our current model that glucose derepression of gluconeogenic genes needs Cat8p phosphorylation and additionally show that a still unknown transcriptional activator is also involved.

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Interactions between the ankyrin repeat-containing protein Akrlp and the pheromone response pathway in Saccharomyces cerevisiae

Trends in Genetics ◽

10.1016/0168-9525(96)81459-4 ◽

1996 ◽

Vol 12 (8) ◽

pp. 291

Keyword(s):

Saccharomyces Cerevisiae ◽

Ankyrin Repeat ◽

Pheromone Response ◽

Pheromone Response Pathway

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Utilization of the Mating Scaffold Protein in the Evolution of a New Signal Transduction Pathway for Biofilm Development

mBio ◽

10.1128/mbio.00237-10 ◽

2011 ◽

Vol 2 (1) ◽

Cited By ~ 17

Author(s):

Song Yi ◽

Nidhi Sahni ◽

Karla J. Daniels ◽

Kevin L. Lu ◽

Guanghua Huang ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Candida Albicans ◽

Scaffold Protein ◽

White Cell ◽

Pheromone Response ◽

Content Type ◽

Pheromone Response Pathway ◽

Protein Map ◽

Mitogen Activated Protein ◽

Kinase Cascade

ABSTRACTAmong the hemiascomycetes, onlyCandida albicansmust switch from the white phenotype to the opaque phenotype to mate. In the recent evolution of this transition, mating-incompetent white cells acquired a unique response to mating pheromone, resulting in the formation of a white cell biofilm that facilitates mating. All of the upstream components of the white cell response pathway so far analyzed have been shown to be derived from the ancestral pathway involved in mating, except for the mitogen-activated protein (MAP) kinase scaffold protein, which had not been identified. Here, through binding and mutational studies, it is demonstrated that in both the opaque and the white cell pheromone responses, Cst5 is the scaffold protein, supporting the evolutionary scenario proposed. Although Cst5 plays the same role in tethering the MAP kinases as Ste5 does inSaccharomyces cerevisiae, Cst5 is approximately one-third the size and has only one rather than four phosphorylation sites involved in activation and cytoplasmic relocalization.IMPORTANCECandida albicansmust switch from white to opaque to mate. Opaque cells then release pheromone, which not only induces cells to mate but also in a unique fashion induces mating-incompetent white cells to form biofilms that facilitate opaque cell mating. All of the tested upstream components of the newly evolved white cell pheromone response pathway, from the receptor to the mitogen-activated protein (MAP) kinase cascade, are the same as those of the conserved opaque cell response pathway. One key element, however, remained unidentified, the scaffold protein for the kinase cascade. Here, we demonstrate that Cst5, a homolog of theSaccharomyces cerevisiaescaffold protein Ste5, functions as the scaffold protein in both the opaque and the white cell pheromone responses. Pheromone induces Cst5 phosphorylation, which is involved in activation and cytoplasmic localization of Cst5. However, Cst5 contains only one phosphorylation site, not four as in theS. cerevisiaeortholog Ste5. These results support the hypothesis that the entire upper portion of the newly evolved white cell pheromone response pathway is derived from the conserved pheromone response pathway in the mating process.

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