scholarly journals Glucose-induced inactivation of mitochondrial enzymes in the yeast Saccharomyces cerevisiae

1981 ◽  
Vol 198 (2) ◽  
pp. 281-287 ◽  
Author(s):  
M Takeda
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Malate Dehydrogenase ◽  
Mitochondrial Enzymes ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cytoplasmic Proteins ◽  
Fructose 1,6 Bisphosphatase ◽  
Specific Activities

1. Addition of glucose induced an inactivation of mitochondrial enzymes in the yeast Saccharomyces cerevisiae containing normal mitochondrial particles. 2. The glucose-induced inactivation of mitochondrial enzymes was inhibited by the presence of cycloheximide. 3. Pepstatin also inhibited the inactivation, but phenylmethanesulphonyl fluoride accelerated the inactivation. 4. The specific activities of fructose 1,6-bisphosphatase and cytoplasmic malate dehydrogenase were decreased on the exposure to glucose, as well as those of the mitochondrial enzymes. However, the glucose-induced inactivation of cytoplasmic enzymes was not inhibited by the presence of pepstatin. 5. The specific activities of hexokinase and phosphofructokinase, which are cytoplasmic enzymes were increased by the addition of glucose, and this effect was not affected by pepstatin. 6. Addition of glucose resulted in an increase in the synthesis of proteins of the mitochondria and the cytosol, and simultaneously in degradation of these mitochondrial and cytoplasmic proteins.

EFFECT OF PREGNANCY ON CYTOPLASMIC AND MITOCHONDRIAL ENZYMES IN HUMAN AND ANIMAL MYOMETRIUM

1974 ◽  
Vol 77 (2) ◽  
pp. 368-379 ◽  
Author(s):  
Helmut Geyer ◽  
Michael Riebschläger
Keyword(s):  
Lactate Dehydrogenase ◽  
Enzymatic Activity ◽  
Malate Dehydrogenase ◽  
Human Tissue ◽  
Human Myometrium ◽  
Mitochondrial Enzymes ◽  
Cellular Compartment ◽  
Cellular Localisation ◽  
Specific Activities ◽  
Mitochondrial Malate Dehydrogenase

ABSTRACT An investigation was made on the influence of pregnancy on the specific activities of cytoplasmic (lactate dehydrogenase2), cytoplasmic malate dehydrogenase) and mitochondrial enzymes (glutamate dehydrogenase, mitochondrial malate dehydrogenase, cytochrome-c-oxidase) in the human and animal myometrium. The activities were related to DNA. The specific activities of all the investigated enzymes increased. This rise in activity depended on the cellular localisation of the enzyme. The activity of all enzymes in one cellular compartment changed to the same extent. This change varied according to species. With regard to the human tissue, the increase of the cytoplasmic enzymes was larger than that of the mitochondrial enzymes. In the rat, however, a significantly larger increase of the mitochondrial enzymes was found. The increase in the specific activities of the cytoplasmic enzymes in the human and rat was proportional to the protein-content and to the hypertrophy of the cells. It was concluded that the number of mitochondria or their enzymatic activity increased in both species during pregnancy – in each species, however, to a different extent. The pattern of the LDH-isoenzymes in the myometrium changed in the same manner in the human myometrium as in the rat. The percentage of M subunits of LDH compared to H subunits rose in both cases during pregnancy.

scholarly journals Modulation of the voltage-dependent anion-selective channel by cytoplasmic proteins from wild type and the channel depleted cells of Saccharomyces cerevisiae.

2003 ◽  
Vol 50 (2) ◽  
pp. 415-424 ◽  
Author(s):  
Hanna Kmita ◽  
Małgorzata Budzińska ◽  
Olgierd Stobienia
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein S ◽  
Mitochondrial Outer Membrane ◽  
Cell Physiology ◽  
Intermembrane Space ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cytoplasmic Proteins ◽  
Voltage Dependent ◽  
Selective Channel

It is well known that effective exchange of metabolites between mitochondria and the cytoplasm is essential for cell physiology. The key step of the exchange is transport across the mitochondrial outer membrane, which is supported by the voltage-dependent anion-selective channel (VDAC). Therefore, it is clear that the permeability of VDAC must be regulated to adjust its activity to the actual cell needs. VDAC-modulating activities, often referred to as the VDAC modulator, were identified in the intermembrane space of different organism mitochondria but the responsible protein(s) has not been identified as yet. Because the VDAC modulator was reported to act on VDAC of intact mitochondria when added to the cytoplasmic side it has been speculated that a similar modulating activity might be present in the cytoplasm. To check the speculation we used mitochondria of the yeast Saccharomyces cerevisiae as they constitute a perfect model to study VDAC modulation. The mitochondria contain only a single isoform of VDAC and it is possible to obtain viable mutants devoid of the channel (Deltapor1). Moreover, we have recently characterised a VDAC-modulating activity located in the intermembrane space of wild type and Deltapor1 S. cerevisiae mitochondria. Here, we report that the cytoplasm of wild type and Deltapor1 cells of S. cerevisiae contains a VDAC-modulating activity as measured in a reconstituted system and with intact mitochondria. Since quantitative differences were observed between the modulating fractions isolated from wild type and Deltapor1 cells when they were studied with intact wild type mitochondria as well as by protein electrophoresis it might be concluded that VDAC may influence the properties of the involved cytoplasmic proteins. Moreover, the VDAC-modulating activity in the cytoplasm differs distinctly from that reported for the mitochondrial intermembrane space. Nevertheless, both these activities may contribute efficiently to VDAC regulation. Thus, the identification of the proteins is very important.

scholarly journals Seg1 controls eisosome assembly and shape

2012 ◽  
Vol 198 (3) ◽  
pp. 405-420 ◽  
Author(s):  
Karen E. Moreira ◽  
Sebastian Schuck ◽  
Bianca Schrul ◽  
Florian Fröhlich ◽  
James B. Moseley ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Plasma Membrane ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Budding Yeast ◽  
Yeast Saccharomyces Cerevisiae ◽  
Normal Plasma ◽  
Cytoplasmic Proteins ◽  
Stable Domains

Eisosomes are stable domains at the plasma membrane of the budding yeast Saccharomyces cerevisiae and have been proposed to function in endocytosis. Eisosomes are composed of two main cytoplasmic proteins, Pil1 and Lsp1, that form a scaffold around furrow-like plasma membrane invaginations. We show here that the poorly characterized eisosome protein Seg1/Ymr086w is important for eisosome biogenesis and architecture. Seg1 was required for efficient incorporation of Pil1 into eisosomes and the generation of normal plasma membrane furrows. Seg1 preceded Pil1 during eisosome formation and established a platform for the assembly of other eisosome components. This platform was further shaped and stabilized upon the arrival of Pil1 and Lsp1. Moreover, Seg1 abundance controlled the shape of eisosomes by determining their length. Similarly, the Schizosaccharomyces pombe Seg1-like protein Sle1 was necessary to generate the filamentous eisosomes present in fission yeast. The function of Seg1 in the stepwise biogenesis of eisosomes reveals striking architectural similarities between eisosomes in yeast and caveolae in mammals.

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