γ-Glutamyl transpeptidase in the yeast Saccharomyces cerevisiae and its role in the vacuolar transport and metabolism of glutathione

2001 ◽  
Vol 359 (3) ◽  
pp. 631-637 ◽  
Author(s):  
Karim MEHDI ◽  
Jacques THIERIE ◽  
Michel J. PENNINCKX
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nitrogen Starvation ◽  
Coupled System ◽  
Vacuolar Membrane ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mutant Strains ◽  
Gsh Metabolism ◽  
Glutamyl Transpeptidase ◽  
Hydrolysis Of ◽  
Wild Type Yeast

In the yeast Saccharomyces cerevisiae, the enzyme γ-glutamyl transpeptidase (γ-GT; EC 2.3.2.2) is a glycoprotein that is bound to the vacuolar membrane. The kinetic parameters of GSH transport into isolated vacuoles were measured using intact vacuoles isolated from the wild-type yeast strain Σ1278b, under conditions of γ-GT synthesis (nitrogen starvation) and repression (growth in the presence of ammonium ions). Vacuoles devoid of γ-GT displayed a Km (app) of 18±2mM and a Vmax (app) of 48.5±5nmol of GSH/min per mg of protein. Vacuoles containing γ-GT displayed practically the same Km, but a higher Vmax (app) (150±12nmol of GSH/min per mg of protein). Vacuoles prepared from a disruptant lacking γ-GT showed no increase in Vmax (app) with nitrogen starvation. From a comparison of the transport data obtained for vacuoles isolated from various reference and mutant strains, it appears that the yeast cadmium factor 1 (YCF1) transport system accounts for approx. 70% of the GSH transport capacity of the vacuoles, the remaining 30% being due to a vacuolar (H+) ATPase-coupled system. The Vmax (app)-increasing effect of γ-GT concerns only the YCF1 system. γ-GT in the vacuolar membrane activates the Ycf1p transporter, either directly or indirectly. Moreover, GSH accumulating in the vacuolar space may exert a feedback effect on its own entry. Excretion of glutamate from radiolabelled GSH in isolated vacuoles containing γ-GT was also measured. It is proposed that γ-GT and a l-Cys-Gly dipeptidase catalyse the complete hydrolysis of GSH stored in the central vacuole of the yeast cell, prior to release of its constitutive amino acids l-glutamate, l-cysteine and glycine into the cytoplasm. Yeast appears to be a useful model for studying γ-GT physiology and GSH metabolism.

Evolution of ethylene by Saccharomyces cerevisiae as influenced by the carbon source for growth and the presence of air

1978 ◽  
Vol 24 (6) ◽  
pp. 637-642 ◽  
Author(s):  
K. C. Thomas ◽  
Mary Spencer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Ethylene Production ◽  
Atp Synthesis ◽  
Yeast Cells ◽  
Yeast Culture ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Absolute Requirement ◽  
Wild Type Yeast

Effects of the carbon source and oxygen on ethylene production by the yeast Saccharomyces cerevisiae have been studied. The amounts of ethylene evolved by the yeast culture were less than those detected in the blank (an equal volume of uninoculated medium), suggesting a net absorption of ethylene by the yeast cells. Addition of glucose to the lactate-grown yeast culture induced ethylene production. This glucose-induced stimulation of ethylene production was inhibited to a great extent by cycloheximide. Results suggested that the yeast cells in the presence of glucose synthesized an ethylene precursor and passed it into the medium. The conversion of this precursor to ethylene might be stimulated by oxygen. The fact that ethylene was produced by the yeast growing anaerobically and also by respiration-deficient mutants isolated from the wild-type yeast suggested that mitochondrial ATP synthesis was not an absolute requirement for ethylene biogenesis.

scholarly journals The essential DNA polymerases delta and epsilon are involved in repair of UV-damaged DNA in the yeast Saccharomyces cerevisiae.

1999 ◽  
Vol 46 (2) ◽  
pp. 289-298 ◽  
Author(s):  
A Hałas ◽  
Z Policińska ◽  
H Baranowska ◽  
W J Jachymczyk
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Repair ◽  
Uv Irradiation ◽  
Dna Polymerases ◽  
Relative Molecular Mass ◽  
Yeast Saccharomyces Cerevisiae ◽  
Strand Breaks ◽  
Single Strand Breaks ◽  
Mutant Strains ◽  
Cellular Dna

We have studied the ability of yeast DNA polymerases to carry out repair of lesions caused by UV irradiation in Saccharomyces cerevisiae. By the analysis of postirradiation relative molecular mass changes in cellular DNA of different DNA polymerases mutant strains, it was established that mutations in DNA polymerases delta and epsilon showed accumulation of single-strand breaks indicating defective repair. Mutations in other DNA polymerase genes exhibited no defects in DNA repair. Thus, the data obtained suggest that DNA polymerases delta and epsilon are both necessary for DNA replication and for repair of lesions caused by UV irradiation. The results are discussed in the light of current concepts concerning the specificity of DNA polymerases in DNA repair.

Direction of chromosome rearrangements in Saccharomyces cerevisiae by use of his3 recombinational substrates

1988 ◽  
Vol 8 (10) ◽  
pp. 4370-4380
Author(s):  
M T Fasullo ◽  
R W Davis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Chromosomal Dna ◽  
Yeast Saccharomyces Cerevisiae ◽  
Coding Sequences ◽  
Mutant Strains ◽  
Genetic Techniques ◽  
Orthogonal Field ◽  
His3 Gene ◽  
Tandem Duplications

We used the his3 recombinational substrates (his3 fragments) to direct large interchromosomal (translocations) and intrachromosomal (deletions and tandem duplications) rearrangements in the yeast Saccharomyces cerevisiae. In strains completely deleted for the wild-type HIS3 gene, his3 fragments, one containing a deletion of 5' amino acid coding sequences and the other containing a deletion of 3' amino acid coding sequences, were first placed at preselected sites by homologous recombination. His+ revertants that arose via spontaneous mitotic recombination between the two his3 fragments were selected. This strategy was used to direct rearrangements in both RAD52+ and rad52 mutant strains. Translocations occurred in the RAD52+ genetic background and were characterized by orthogonal field alternating gel electrophoresis of yeast chromosomal DNA and by standard genetic techniques. An unexpected translocation was also identified in which HIS3 sequences were amplified. Two types of tandem duplications of the GAL(7, 10, 1) locus were also directed, and one type was not observed in rad52 mutants. Recombination mechanisms are discussed to account for these differences.

scholarly journals Purification of profilin from Saccharomyces cerevisiae and analysis of profilin-deficient cells.

1990 ◽  
Vol 110 (1) ◽  
pp. 105-114 ◽  
Author(s):  
B K Haarer ◽  
S H Lillie ◽  
A E Adams ◽  
V Magdolen ◽  
W Bandlow ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Actin Polymerization ◽  
Yeast Cells ◽  
Predicted Amino Acid Sequence ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Ellipsoidal Shape ◽  
Hydrolysis Of

We have isolated profilin from yeast (Saccharomyces cerevisiae) and have microsequenced a portion of the protein to confirm its identity; the region microsequenced agrees with the predicted amino acid sequence from a profilin gene recently isolated from S. cerevisiae (Magdolen, V., U. Oechsner, G. Müller, and W. Bandlow. 1988. Mol. Cell. Biol. 8:5108-5115). Yeast profilin resembles profilins from other organisms in molecular mass and in the ability to bind to polyproline, retard the rate of actin polymerization, and inhibit hydrolysis of ATP by monomeric actin. Using strains that carry disruptions or deletions of the profilin gene, we have found that, under appropriate conditions, cells can survive without detectable profilin. Such cells grow slowly, are temperature sensitive, lose the normal ellipsoidal shape of yeast cells, often become multinucleate, and generally grow much larger than wild-type cells. In addition, these cells exhibit delocalized deposition of cell wall chitin and have dramatically altered actin distributions.

scholarly journals Vacuolar protein Tag1 and Atg1–Atg13 regulate autophagy termination during persistent starvation in S. cerevisiae

2021 ◽  
Vol 134 (4) ◽  
pp. jcs253682
Author(s):  
Shintaro Kira ◽  
Masafumi Noguchi ◽  
Yasuhiro Araki ◽  
Yu Oikawa ◽  
Tamotsu Yoshimori ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Membrane Protein ◽  
Nitrogen Starvation ◽  
Genetic Screen ◽  
Vacuolar Membrane ◽  
Phagophore Assembly Site ◽  
Vacuolar Protein ◽  
Assembly Site ◽  
Starvation Conditions

ABSTRACTUnder starvation conditions, cells degrade their own components via autophagy in order to provide sufficient nutrients to ensure their survival. However, even if starvation persists, the cell is not completely degraded through autophagy, implying the existence of some kind of termination mechanism. In the yeast Saccharomyces cerevisiae, autophagy is terminated after 10–12 h of nitrogen starvation. In this study, we found that termination is mediated by re-phosphorylation of Atg13 by the Atg1 protein kinase, which is also affected by PP2C phosphatases, and the eventual dispersion of the pre-autophagosomal structure, also known as the phagophore assembly site (PAS). In a genetic screen, we identified an uncharacterized vacuolar membrane protein, Tag1, as a factor responsible for the termination of autophagy. Re-phosphorylation of Atg13 and eventual PAS dispersal were defective in the Δtag1 mutant. The vacuolar luminal domain of Tag1 and autophagic progression are important for the behaviors of Tag1. Together, our findings reveal the mechanism and factors responsible for termination of autophagy in yeast.

scholarly journals Ubiquinone is not required for proton conductance by uncoupling protein 1 in yeast mitochondria

2004 ◽  
Vol 379 (2) ◽  
pp. 309-315 ◽  
Author(s):  
Telma C. ESTEVES ◽  
Karim S. ECHTAY ◽  
Tanya JONASSEN ◽  
Catherine F. CLARKE ◽  
Martin D. BRAND
Keyword(s):  
Proton Transport ◽  
Uncoupling Protein ◽  
Coenzyme Q ◽  
Yeast Mitochondria ◽  
Proton Conductance ◽  
Wild Type ◽  
Uncoupling Protein 1 ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mutant Strains ◽  
Wild Type Yeast

Q (coenzyme Q or ubiquinone) is reported to be a cofactor obligatory for proton transport by UCPs (uncoupling proteins) in liposomes [Echtay, Winkler and Klingenberg (2000) Nature (London) 408, 609–613] and for increasing the binding of the activator retinoic acid to UCP1 [Tomás, Ledesma and Rial (2002) FEBS Lett. 526, 63–65]. In the present study, yeast (Saccharomyces cerevisiae) mutant strains lacking Q and expressing UCP1 were used to determine whether Q was required for UCP function in mitochondria. Wild-type yeast strain and two mutant strains (CENΔCOQ3 and CENΔCOQ2), both not capable of synthesizing Q, were transformed with the mouse UCP1 gene. UCP1 activity was measured as fatty acid-dependent, GDP-sensitive proton conductance in mitochondria isolated from the cells. The activity of UCP1 was similar in both Q-containing and -deficient yeast mitochondria. We conclude that Q is neither an obligatory cofactor nor an activator of proton transport by UCP1 when it is expressed in yeast mitochondria.

Use of sugarcane molasses “B” as an alternative for ethanol production with wild-type yeast Saccharomyces cerevisiae ITV-01 at high sugar concentrations

2011 ◽  
Vol 35 (4) ◽  
pp. 605-614 ◽  
Author(s):  
C. L. Fernández-López ◽  
B. Torrestiana-Sánchez ◽  
M. A. Salgado-Cervantes ◽  
P. G. Mendoza García ◽  
M. G. Aguilar-Uscanga
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Sugarcane Molasses ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
High Sugar ◽  
Wild Type Yeast
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