scholarly journals The effects of Gpr1 and Gpa2 on the mating pathway in Saccharomyces cerevisiae

2013 ◽  
Vol 27 (S1) ◽  
Author(s):  
Zachary A Duck ◽  
Elisabeth Klouda ◽  
David Haskins ◽  
Janelle Johnson ◽  
Katie Selcer ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Pathway

scholarly journals Systematic deletion analysis of components in a glucose sensing pathway and the mating pathway in Saccharomyces cerevisiae points to significant interdependence

2013 ◽  
Vol 27 (S1) ◽  
Author(s):  
Elisabeth Klouda ◽  
Joshua E Denny ◽  
Zachary A Duck ◽  
David Haskins ◽  
Janelle L Johnson ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Glucose Sensing ◽  
Deletion Analysis ◽  
Mating Pathway

scholarly journals Genetic Analysis of Default Mating Behavior in Saccharomyces cerevisiae

Genetics ◽  
1997 ◽  
Vol 146 (1) ◽  
pp. 39-55 ◽  
Author(s):  
Russell Dorer ◽  
Charles Boone ◽  
Tyler Kimbrough ◽  
Joshua Kim ◽  
Leland H Hartwell
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Genetic Analysis ◽  
Mating Behavior ◽  
Cell Fusion ◽  
Yeast Cells ◽  
Stringent Requirement ◽  
Mating Partner ◽  
Mating Efficiency ◽  
Multiple Copies ◽  
Mating Pathway

Haploid Saccharomyces cerevisiae cells find each other during conjugation by orienting their growth toward each other along pheromone gradients (chemotropism). However, when their receptors are saturated for pheromone binding, yeast cells must select a mate by executing a default pathway in which they choose a mating partner at random. We previously demonstrated that this default pathway requires the SPA2 gene. In this report we show that the default mating pathway also requires the AXL1, FUS1, FUS2, FUS3, PEAZ, RVS161, and BNI1 genes. These genes, including SPA2, are also important for efficient cell fusion during chemotropic mating. Cells containing null mutations in these genes display defects in cell fusion that subtly affect mating efficiency. In addition, we found that the defect in default mating caused by mutations in SPA2 is partially suppressed by multiple copies of two genes, FUS2 and MFA2. These findings uncover a molecular relationship between default mating and cell fusion. Moreover, because axl1 mutants secrete reduced levels of a-factor and are defective at both cell fusion and default mating, these results reveal an important role for a-factor in cell fusion and default mating. We suggest that default mating places a more stringent requirement on some aspects of cell fusion than does chemotropic mating.

scholarly journals Evidence that mating by the Saccharomyces cerevisiae gpa1Val50 mutant occurs through the default mating pathway and a suggestion of a role for ubiquitin-mediated proteolysis.

1997 ◽  
Vol 8 (9) ◽  
pp. 1649-1664 ◽  
Author(s):  
B E Xu ◽  
J Kurjan
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Alpha Subunit ◽  
Growth Defect ◽  
Positive Component ◽  
Pheromone Response ◽  
Pheromone Receptor ◽  
Pheromone Response Pathway ◽  
Epistasis Analysis ◽  
Negative Role ◽  
Mating Pathway

The yeast G alpha subunit, Gpa1p, plays a negative role in the pheromone response pathway. The gpa1Val50 mutant was previously shown to have a growth defect, consistent with the GTPase defect predicted for this mutation, and greatly reduced mating. Various explanations for the mating defect have been proposed. One approach to analyze the gpa1Val50 mating defect involved epistasis analysis. The low mating of the gpa1Val50 mutant was independent of the pheromone receptor; therefore, it results from intracellular activation of the pathway, consistent with a GTPase defect. This result suggests that gpa1Val50 mating occurs through the default rather than the chemotropic pathway involved in pheromone response. We therefore tested the effect of a spa2 mutation on gpa1Val50 mating, because Spa2p has been implicated in the default pathway. The spa2 mutation greatly reduced the mating of the gpa1Val50 mutant, suggesting that gpa1Val50 mating occurs predominantly through the default pathway. In a second approach to investigate the gpa1Val50 phenotypes, suppressors of the gpa1Val50 mating defect were isolated. Two suppressor genes corresponded to SON1/UFD5 and SEN3, which are implicated in ubiquitin-mediated proteolysis. On the basis of these results, we suggest that a positive component of the default mating pathway is subject to ubiquitin-mediated degradation.

scholarly journals Coordination of the mating and cell integrity mitogen-activated protein kinase pathways in Saccharomyces cerevisiae.

1997 ◽  
Vol 17 (11) ◽  
pp. 6517-6525 ◽  
Author(s):  
B M Buehrer ◽  
B Errede
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Map Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Cell Integrity ◽  
Mating Partner ◽  
Kinase Activation ◽  
Mitogen Activated Protein ◽  
Kinase Cascade ◽  
Mating Pathway ◽  
Transcriptional Output

Mating pheromone stimulates a mitogen-activated protein (MAP) kinase activation pathway in Saccharomyces cerevisiae that induces cells to differentiate and form projections oriented toward the gradient of pheromone secreted by a mating partner. The polarized growth of mating projections involves new cell wall synthesis, a process that relies on activation of the cell integrity MAP kinase, Mpk1. In this report, we show that Mpk1 activation during pheromone induction requires the transcriptional output of the mating pathway and protein synthesis. Consequently, Mpk1 activation occurs subsequent to the activation of the mating pathway MAP kinase cascade. Additionally, Spa2 and Bni1, a formin family member, are two coil-coil-related proteins that are involved in the timing and other aspects of mating projection formation. Both proteins also affect the timing and extent of Mpk1 activation. This correlation suggests that projection formation comprises part of the pheromone-induced signal that coordinates Mpk1 activation with mating differentiation. Stimulation of Mpk1 activity occurs through the cell integrity phosphorylation cascade and depends on Pkc1 and the redundant MAP/Erk kinases (MEKs), Mkk1 and Mkk2. Surprisingly, Mpk1 activation by pheromone was only partially impaired in cells lacking the MEK kinase Bck1. This Bck1-independent mechanism reveals the existence of an alternative activator of Mkk1/Mkk2 in some strain backgrounds that at least functions under pheromone-induced conditions.

scholarly journals The osmoregulatory pathway represses mating pathway activity in Saccharomyces cerevisiae: isolation of a FUS3 mutant that is insensitive to the repression mechanism.

1996 ◽  
Vol 16 (12) ◽  
pp. 6715-6723 ◽  
Author(s):  
J P Hall ◽  
V Cherkasova ◽  
E Elion ◽  
M C Gustin ◽  
E Winter
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Map Kinase ◽  
Map Kinases ◽  
Hog Pathway ◽  
Pathway Activity ◽  
Mitogen Activated Protein ◽  
Increased Sensitivity ◽  
Mating Pathway ◽  
Single Cell Type

Mitogen-activated protein (MAP) kinase cascades are conserved signal transduction pathways that are required for eukaryotic cells to respond to a variety of stimuli. Multiple MAP kinase pathways can function within a single cell type; therefore, mechanisms that insulate one MAP kinase pathway from adventitious activations by parallel pathways may exist. We have studied interactions between the mating pheromone response and the osmoregulatory (high-osmolarity glycerol response [HOG]) pathways in Saccharomyces cerevisiae which utilize the MAP kinases Fus3p and Hog1p, respectively. Inactivating mutations in HOG pathway kinases cause an increase in the phosphotyrosine content of Fus3p, greater expression of pheromone-responsive genes, and increased sensitivity to growth arrest by pheromone. Therefore, the HOG pathway represses mating pathway activity. In a HOG1+ strain, Fus3p phosphotyrosine increases modestly and transiently following an increase in the extracellular osmolarity; however, it increases to a greater extent and for a sustained duration in a hog1-delta strain. Thus, the HOG-mediated repression of mating pathway activity may insulate the mating pathway from activation by osmotic stress. A FUS3 allele whose gene product is resistant to the HOG-mediated repression of its phosphotyrosine content has been isolated. This mutant encodes an amino acid substitution in the highly conserved DPXDEP motif in subdomain XI. Other investigators have shown that the corresponding amino acid is also mutated in a gain-of-function allele of the MAP kinase encoded by the rolled locus in Drosophila melanogaster. These data suggest that the DPXDEP motif plays a role in the negative regulation of MAP kinases.

scholarly journals Evolutionary Reshaping of Fungal Mating Pathway Scaffold Proteins

mBio ◽  
2011 ◽  
Vol 2 (1) ◽  
Author(s):  
Pierre Côte ◽  
Traian Sulea ◽  
Daniel Dignard ◽  
Cunle Wu ◽  
Malcolm Whiteway
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Map Kinase ◽  
Scaffold Proteins ◽  
Cellular Polarity ◽  
Pathogenic Yeast ◽  
Content Type ◽  
Fungal Lineage ◽  
Protein Map ◽  
Mitogen Activated Protein ◽  
Mating Pathway

ABSTRACTScaffold proteins play central roles in the function of many signaling pathways. Among the best-studied examples are the Ste5 and Far1 proteins of the yeastSaccharomyces cerevisiae. These proteins contain three conserved modules, the RING and PH domains, characteristic of some ubiquitin-ligating enzymes, and a vWA domain implicated in protein-protein interactions. In yeast, Ste5p regulates the mating pathway kinases while Far1p coordinates the cellular polarity machinery. Within the fungal lineage, theBasidiomycetesand thePezizomycetescontain a single Far1-like protein, while severalSaccharomycotinaspecies, belonging to the CTG (Candida) clade, contain both a classic Far1-like protein and a Ste5-like protein that lacks the vWA domain. We analyzed the function ofC. albicansSte5p (Cst5p), a member of this class of structurally distinct Ste5 proteins.CST5is essential for mating and still coordinates the mitogen-activated protein (MAP) kinase (MAPK) cascade elements in the absence of the vWA domain; Cst5p interacts with the MEK kinase (MEKK)C. albicansSte11p (CaSte11p) and the MAPK Cek1 as well as with the MEK Hst7 in a vWA domain-independent manner. Cst5p can homodimerize, similar to Ste5p, but can also heterodimerize with Far1p, potentially forming heteromeric signaling scaffolds. We found direct binding between the MEKK CaSte11p and the MEK Hst7p that depends on a mobile acidic loop absent fromS. cerevisiaeSte11p but related to the Ste7-binding region within the vWA domain of Ste5p. Thus, the fungal lineage has restructured specific scaffolding modules to coordinate the proteins required to direct the gene expression, polarity, and cell cycle regulation essential for mating.IMPORTANCEThe mitogen-activated protein (MAP) kinase cascade is an extensively used signaling module in eukaryotic cells, and the ability to regulate these modules is critical for ensuring proper responses to a wide variety of stimuli. One way that cells regulate this signaling module is through scaffold proteins that insulate related pathways against cross talk, improve signaling efficiency, and ensure that signals are connected to the correct response. The Ste5 scaffold of theS. cerevisiaemating response is a well-studied representative of this class of proteins. Using bioinformatics, structural modeling, and molecular genetic approaches, we have investigated the equivalent scaffold in the pathogenic yeastCandida albicans. We show that theC. albicansprotein is structurally distinct from that ofSaccharomyces cerevisiaebut still provides similar functions. Increases in pathway complexity have been associated with changes in scaffold connectivity, and overall, the tethering capacity of the scaffolds has been more conserved than their structural organization.

Anti-Saccharomyces cerevisiae Antibodies in Inflammatory Bowel Disease: a Family Study

2001 ◽  
Vol 36 (2) ◽  
pp. 196-201 ◽  
Author(s):  
F. Seibold ◽  
O. Stich ◽  
R. Hufnagl ◽  
S. Kamil ◽  
M. Scheurlen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Inflammatory Bowel Disease ◽  
Bowel Disease ◽  
Family Study ◽  
Inflammatory Bowel
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