scholarly journals Candida albicans Msi3p, a homolog of the Saccharomyces cerevisiae Sse1p of the Hsp70 family, is involved in cell growth and fluconazole tolerance

2012 ◽  
Vol 12 (6) ◽  
pp. 728-737 ◽  
Author(s):  
Jun-ichi Nagao ◽  
Tamaki Cho ◽  
Jun Uno ◽  
Keigo Ueno ◽  
Rieko Imayoshi ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Cell Growth ◽  
Hsp70 Family

scholarly journals Barrier Activity in Candida albicans Mediates Pheromone Degradation and Promotes Mating

2007 ◽  
Vol 6 (6) ◽  
pp. 907-918 ◽  
Author(s):  
Dana Schaefer ◽  
Pierre Côte ◽  
Malcolm Whiteway ◽  
Richard J. Bennett
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Cell Growth ◽  
Cell Fusion ◽  
Aspartyl Protease ◽  
Wild Type ◽  
Pheromone Activity ◽  
Important Regulator ◽  
Mutant Cells ◽  
Type Strains

ABSTRACT Mating in Candida albicans and Saccharomyces cerevisiae is regulated by the secretion of peptide pheromones that initiate the mating process. An important regulator of pheromone activity in S. cerevisiae is barrier activity, involving an extracellular aspartyl protease encoded by the BAR1 gene that degrades the alpha pheromone. We have characterized an equivalent barrier activity in C. albicans and demonstrate that the loss of C. albicans BAR1 activity results in opaque a cells exhibiting hypersensitivity to alpha pheromone. Hypersensitivity to pheromone is clearly seen in halo assays; in response to alpha pheromone, a lawn of C. albicans Δbar1 mutant cells produces a marked zone in which cell growth is inhibited, whereas wild-type strains fail to show halo formation. C. albicans mutants lacking BAR1 also exhibit a striking mating defect in a cells, but not in α cells, due to overstimulation of the response to alpha pheromone. The block to mating occurs prior to cell fusion, as very few mating zygotes were observed in mixes of Δbar1 a and α cells. Finally, in a barrier assay using a highly pheromone-sensitive strain, we were able to demonstrate that barrier activity in C. albicans is dependent on Bar1p. These studies reveal that a barrier activity to alpha pheromone exists in C. albicans and that the activity is analogous to that caused by Bar1p in S. cerevisiae.

scholarly journals Posttranslational Modifications of Proteins in the Pathobiology of Medically Relevant Fungi

2011 ◽  
Vol 11 (2) ◽  
pp. 98-108 ◽  
Author(s):  
Michelle D. Leach ◽  
Alistair J. P. Brown
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Cell Growth ◽  
Aspergillus Fumigatus ◽  
Posttranslational Modifications ◽  
Fungal Pathogens ◽  
Content Type ◽  
Cellular Processes ◽  
Peptide Modifications ◽  
Fungal Kingdom

ABSTRACTPosttranslational modifications of proteins drive a wide variety of cellular processes in eukaryotes, regulating cell growth and division as well as adaptive and developmental processes. With regard to the fungal kingdom, most information about posttranslational modifications has been generated through studies of the model yeastsSaccharomyces cerevisiaeandSchizosaccharomyces pombe, where, for example, the roles of protein phosphorylation, glycosylation, acetylation, ubiquitination, sumoylation, and neddylation have been dissected. More recently, information has begun to emerge for the medically important fungal pathogensCandida albicans,Aspergillus fumigatus, andCryptococcus neoformans, highlighting the relevance of posttranslational modifications for virulence. We review the available literature on protein modifications in fungal pathogens, focusing in particular upon the reversible peptide modifications sumoylation, ubiquitination, and neddylation.

scholarly journals The rye Mutants Identify a Role for Ssn/Srb Proteins of the RNA Polymerase II Holoenzyme During Stationary Phase Entry in Saccharomyces cerevisiae

Genetics ◽  
2001 ◽  
Vol 157 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Ya-Wen Chang ◽  
Susie C Howard ◽  
Yelena V Budovskaya ◽  
Jasper Rine ◽  
Paul K Herman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Growth ◽  
Rna Polymerase ◽  
Stationary Phase ◽  
Yeast Cell ◽  
Rna Polymerase Ii ◽  
Transcriptional Response ◽  
Nutrient Deprivation ◽  
Ras Signaling ◽  
Rna Polymerase Ii Holoenzyme

Abstract Saccharomyces cerevisiae cells enter into a distinct resting state, known as stationary phase, in response to specific types of nutrient deprivation. We have identified a collection of mutants that exhibited a defective transcriptional response to nutrient limitation and failed to enter into a normal stationary phase. These rye mutants were isolated on the basis of defects in the regulation of YGP1 expression. In wild-type cells, YGP1 levels increased during the growth arrest caused by nutrient deprivation or inactivation of the Ras signaling pathway. In contrast, the levels of YGP1 and related genes were significantly elevated in the rye mutants during log phase growth. The rye defects were not specific to this YGP1 response as these mutants also exhibited multiple defects in stationary phase properties, including an inability to survive periods of prolonged starvation. These data indicated that the RYE genes might encode important regulators of yeast cell growth. Interestingly, three of the RYE genes encoded the Ssn/Srb proteins, Srb9p, Srb10p, and Srb11p, which are associated with the RNA polymerase II holoenzyme. Thus, the RNA polymerase II holoenzyme may be a target of the signaling pathways responsible for coordinating yeast cell growth with nutrient availability.

scholarly journals Divergent Subunit Interactions among Fungal mRNA 5′-Capping Machineries

2002 ◽  
Vol 1 (3) ◽  
pp. 448-457 ◽  
Author(s):  
Toshimitsu Takagi ◽  
Eun-Jung Cho ◽  
Rozmin T. K. Janoo ◽  
Vladimir Polodny ◽  
Yasutaka Takase ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Rna Polymerase Ii ◽  
Subunit Interactions ◽  
Pol Ii ◽  
Mrna Capping ◽  
Capping Enzyme ◽  
Enzyme Subunits ◽  
Carboxyl Terminal

ABSTRACT The Saccharomyces cerevisiae mRNA capping enzyme consists of two subunits: an RNA 5′-triphosphatase (RTPase) and GTP::mRNA guanylyltransferase (GTase). The GTase subunit (Ceg1) binds to the phosphorylated carboxyl-terminal domain of the largest subunit (CTD-P) of RNA polymerase II (pol II), coupling capping with transcription. Ceg1 bound to the CTD-P is inactive unless allosterically activated by interaction with the RTPase subunit (Cet1). For purposes of comparison, we characterize here the related GTases and RTPases from the yeasts Schizosaccharomyces pombe and Candida albicans. Surprisingly, the S. pombe capping enzyme subunits do not interact with each other. Both can independently interact with CTD-P of pol II, and the GTase is not repressed by CTD-P binding. The S. pombe RTPase gene (pct1 +) is essential for viability. Pct1 can replace the S. cerevisiae RTPase when GTase activity is supplied by the S. pombe or mouse enzymes but not by the S. cerevisiae GTase. The C. albicans capping enzyme subunits do interact with each other. However, this interaction is not essential in vivo. Our results reveal an unexpected diversity among the fungal capping machineries.

scholarly journals Overexpression of Candida albicans secretory aspartyl proteinase 2 and its expression in Saccharomyces cerevisiae do not augment virulence in mice

Microbiology ◽  
1998 ◽  
Vol 144 (8) ◽  
pp. 2299-2310 ◽  
Author(s):  
N. Dubois ◽  
A. R. Colina ◽  
F. Aumont ◽  
P. Belhumeur ◽  
L. de Repentigny
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans

scholarly journals A Ste6p/P-glycoprotein homologue from the asexual yeast Candida albicans transports the a-factor mating pheromone in Saccharomyces cerevisiae

1998 ◽  
Vol 27 (3) ◽  
pp. 587-598 ◽  
Author(s):  
Martine Raymond ◽  
Daniel Dignard ◽  
Anne-Marie Alarco ◽  
Norman Mainville ◽  
Beatrice B. Magee ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Mating Pheromone ◽  
P Glycoprotein

scholarly journals The Ras/PKA Signaling Pathway May Control RNA Polymerase II Elongation via the Spt4p/Spt5p Complex in Saccharomyces cerevisiae

Genetics ◽  
2003 ◽  
Vol 165 (3) ◽  
pp. 1059-1070
Author(s):  
Susie C Howard ◽  
Arelis Hester ◽  
Paul K Herman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Growth ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Signaling Pathway ◽  
Elongation Factor ◽  
Ras Signaling ◽  
Elongation Step ◽  
Rna Polymerase Ii Transcription

Abstract The Ras signaling pathway in Saccharomyces cerevisiae controls cell growth via the cAMP-dependent protein kinase, PKA. Recent work has indicated that these effects on growth are due, in part, to the regulation of activities associated with the C-terminal domain (CTD) of the largest subunit of RNA polymerase II. However, the precise target of these Ras effects has remained unknown. This study suggests that Ras/PKA activity regulates the elongation step of the RNA polymerase II transcription process. Several lines of evidence indicate that Spt5p in the Spt4p/Spt5p elongation factor is the likely target of this control. First, the growth of spt4 and spt5 mutants was found to be very sensitive to changes in Ras/PKA signaling activity. Second, mutants with elevated levels of Ras activity shared a number of specific phenotypes with spt5 mutants and vice versa. Finally, Spt5p was efficiently phosphorylated by PKA in vitro. Altogether, the data suggest that the Ras/PKA pathway might be directly targeting a component of the elongating polymerase complex and that this regulation is important for the normal control of yeast cell growth. These data point out the interesting possibility that signal transduction pathways might directly influence the elongation step of RNA polymerase II transcription.

scholarly journals DNA damage and heat shock dually regulate genes in Saccharomyces cerevisiae.

1986 ◽  
Vol 6 (1) ◽  
pp. 90-96 ◽  
Author(s):  
T McClanahan ◽  
K McEntee
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Damage ◽  
Heat Shock ◽  
Shock Treatment ◽  
Northern Hybridization ◽  
Heat Shock Treatment ◽  
Base Pairs ◽  
S1 Nuclease ◽  
Hsp70 Family ◽  
Transcriptional Start Sites

Two Saccharomyces cerevisiae genes isolated in a differential hybridization screening for DNA damage regulation (DDR genes) were also transcriptionally regulated by heat shock treatment. A 0.45-kilobase transcript homologous to the DDRA2 gene and a 1.25-kilobase transcript homologous to the DDR48 gene accumulated after exposure of cells to 4-nitroquinoline-1-oxide (NQO; 1 to 1.5 microgram/ml) or brief heat shock (20 min at 37 degrees C). The DDRA2 transcript, which was undetectable in untreated cells, was induced to high levels by these treatments, and the DDR48 transcript increased more than 10-fold as demonstrated by Northern hybridization analysis. Two findings argue that dual regulation of stress-responsive genes is not common in S. cerevisiae. First, two members of the heat shock-inducible hsp70 family of S. cerevisiae, YG100 and YG102, were not induced by exposure to NQO. Second, at least one other DNA-damage-inducible gene, DIN1, was not regulated by heat shock treatment. We examined the structure of the induced RNA homologous to DDRA2 after heat shock and NQO treatments by S1 nuclease protection experiments. Our results demonstrated that the DDRA2 transcript initiates equally frequently at two sites separated by 5 base pairs. Both transcriptional start sites were utilized when cells were exposed to either NQO or heat shock treatment. These results indicate that DDRA2 and DDR48 are members of a unique dually regulated stress-responsive family of genes in S. cerevisiae.

scholarly journals CaNdt80 Is Involved in Drug Resistance in Candida albicans by Regulating CDR1

2004 ◽  
Vol 48 (12) ◽  
pp. 4505-4512 ◽  
Author(s):  
Chia-Geun Chen ◽  
Yun-Liang Yang ◽  
Hsin-I Shih ◽  
Chia-Li Su ◽  
Hsiu-Jung Lo
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Drug Resistance ◽  
Candida Albicans ◽  
Type Strain ◽  
Antifungal Agents ◽  
Wild Type Strain ◽  
Efflux Pump ◽  
Antifungal Drugs ◽  
Galactosidase Activity ◽  
Wild Type

ABSTRACT Overexpression of CDR1, an efflux pump, is one of the major mechanisms contributing to drug resistance in Candida albicans. CDR1 p-lacZ was constructed and transformed into a Saccharomyces cerevisiae strain so that the lacZ gene could be used as the reporter to monitor the activity of the CDR1 promoter. Overexpression of CaNDT80, the C. albicans homolog of S. cerevisiae NDT80, increases the β-galactosidase activity of the CDR1 p-lacZ construct in S. cerevisiae. Furthermore, mutations in CaNDT80 abolish the induction of CDR1 expression by antifungal agents in C. albicans. Consistently, the Candt80/Candt80 mutant is also more susceptible to antifungal drugs than the wild-type strain. Thus, the gene for CaNdt80 may be the first gene among the regulatory factors involved in drug resistance in C. albicans whose function has been identified.

scholarly journals Prohibitins Regulate Membrane Protein Degradation by the m-AAA Protease in Mitochondria

1999 ◽  
Vol 19 (5) ◽  
pp. 3435-3442 ◽  
Author(s):  
Gregor Steglich ◽  
Walter Neupert ◽  
Thomas Langer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Growth ◽  
Membrane Proteins ◽  
Eukaryotic Cells ◽  
Mitochondrial Morphology ◽  
Regulatory Effect ◽  
Inner Membrane ◽  
Functional Activities ◽  
Native Molecular Mass ◽  
Affect Cell Growth

ABSTRACT Prohibitins comprise a protein family in eukaryotic cells with potential roles in senescence and tumor suppression. Phb1p and Phb2p, members of the prohibitin family in Saccharomyces cerevisiae, have been implicated in the regulation of the replicative life span of the cells and in the maintenance of mitochondrial morphology. The functional activities of these proteins, however, have not been elucidated. We demonstrate here that prohibitins regulate the turnover of membrane proteins by the m-AAA protease, a conserved ATP-dependent protease in the inner membrane of mitochondria. The m-AAA protease is composed of the homologous subunits Yta10p (Afg3p) and Yta12p (Rca1p). Deletion ofPHB1 or PHB2 impairs growth of Δyta10 or Δyta12 cells but does not affect cell growth in the presence of the m-AAA protease. A prohibitin complex with a native molecular mass of approximately 2 MDa containing Phb1p and Phb2p forms a supercomplex with them-AAA protease. Proteolysis of nonassembled inner membrane proteins by the m-AAA protease is accelerated in mitochondria lacking Phb1p or Phb2p, indicating a negative regulatory effect of prohibitins on m-AAA protease activity. These results functionally link members of two conserved protein families in eukaryotes to the degradation of membrane proteins in mitochondria.

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