Miroslava Opekarova - Academia.edu (original) (raw)
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Papers by Miroslava Opekarova
FEBS Letters, Feb 22, 2000
Biochimica Et Biophysica Acta - Biomembranes, May 1, 1981
The high pH-maintaining capacity of yeast suspension after glucose-induced acidification, measure... more The high pH-maintaining capacity of yeast suspension after glucose-induced acidification, measured as its ability to neutralize added alkali, was found to be due mainly to actively extruded acidity (H÷). The buffering action of passively excreted metabolites (CO2, organic acids) and cell surface polyelectrolytes contributed only 15--40% to the overall pH-maintaining capacity which was 10 mmol NaOH/1 per pH unit between pH 3 and 4 and 3.5 mmol NaOH/1 per pH unit between pH 4 and 7. The buffering capacity of yeast cell-free extract was still higher (up to 4.5-times) than that of glucose-supplied cell suspension; addition of glucose to the extract thus produced considerable titratable acidity but negligible net acidity. The glucose-induced acidification of yeast suspension was stimulated by univalent cations in the sequence K* :> Rb ÷ ~ Li ÷ -~ Cs ÷ -~ Na ÷. The processes participating in the acidification and probably also in the creation of extracellular buffering capacity include excretion of CO2 and organic acids, net extrusion of H ÷ and K ÷ (in K÷-free media; in K*~ontaining media this is preceded by an initial rapid K ÷ uptake), and movements of some anions (phosphate, chlorides). The overall process appears to be electrically silent.
European Journal of Cell Biology, Sep 1, 2017
Biochimica Et Biophysica Acta - Biomembranes, Feb 1, 2003
Plant Biology, Jun 7, 2010
Examples from yeast and plant cells are described that show that their plasma membrane is lateral... more Examples from yeast and plant cells are described that show that their plasma membrane is laterally compartmented. Distinct lateral domains encompassing both specific lipids and integral proteins coexist within the plane of the plasma membrane. The compartments are either spatially stable and include distinct sets of proteins, or they are transiently formed to accomplish diverse functions. They are not related to lipid rafts or their clusters, as defined for mammalian cells. This review summarises only well‐documented compartments of plasma membranes from plants and fungi, which have been recognised using microscopic approaches. In several cases, physiological functions of the membrane compartmentation are revealed.
Biochimica Et Biophysica Acta - Biomembranes, Aug 1, 2002
DOAJ (DOAJ: Directory of Open Access Journals), 2014
European journal of cell biology, Jan 3, 2017
We describe a novel mechanism of mRNA decay regulation, which takes place under the conditions of... more We describe a novel mechanism of mRNA decay regulation, which takes place under the conditions of glucose deprivation in the yeast Saccharomyces cerevisiae. The regulation is based on temporally stable sequestration of the main 5'-3' mRNA exoribonuclease Xrn1 at the eisosome, a plasma membrane-associated protein complex organizing a specialized membrane microdomain. As documented by monitoring the decay of a specific mRNA substrate in time, Xrn1-mediated mRNA degradation ceases during the accumulation of Xrn1 at eisosome, but the eisosome-associated Xrn1 retains its functionality and can be re-activated when released to cytoplasm following the addition of glucose. In cells lacking the eisosome organizer Pil1, Xrn1 does not associate with the plasma membrane and its activity is preserved till the stationary phase. Thus, properly assembled eisosome is necessary for this kind of Xrn1 regulation, which occurs in a liquid culture as well as in a differentiated colony.
International Review of Cell and Molecular Biology, 2016
The organization of biological membranes into structurally and functionally distinct lateral micr... more The organization of biological membranes into structurally and functionally distinct lateral microdomains is generally accepted. From bacteria to mammals, laterally compartmentalized membranes seem to be a vital attribute of life. The crucial fraction of our current knowledge about the membrane microdomains has been gained from studies on fungi. In this review we summarize the evidence of the microdomain organization of membranes from fungal cells, with accent on their enormous diversity in composition, temporal dynamics, modes of formation, and recognized engagement in the cell physiology. A special emphasis is laid on the fact that in addition to their other biological functions, membrane microdomains also mediate the communication among different membranes within a eukaryotic cell and coordinate their functions. Involvement of fungal membrane microdomains in stress sensing, regulation of lipid homeostasis, and cell differentiation is discussed more in detail.
The Journal of cell biology, Jan 15, 2008
In this study, we investigate whether the stable segregation of proteins and lipids within the ye... more In this study, we investigate whether the stable segregation of proteins and lipids within the yeast plasma membrane serves a particular biological function. We show that 21 proteins cluster within or associate with the ergosterol-rich membrane compartment of Can1 (MCC). However, proteins of the endocytic machinery are excluded from MCC. In a screen, we identified 28 genes affecting MCC appearance and found that genes involved in lipid biosynthesis and vesicle transport are significantly overrepresented. Deletion of Pil1, a component of eisosomes, or of Nce102, an integral membrane protein of MCC, results in the dissipation of all MCC markers. These deletion mutants also show accelerated endocytosis of MCC-resident permeases Can1 and Fur4. Our data suggest that release from MCC makes these proteins accessible to the endocytic machinery. Addition of arginine to wild-type cells leads to a similar redistribution and increased turnover of Can1. Thus, MCC represents a protective area wit...
Cellular and molecular biology, 1985
Plant Biology, 2010
Examples from yeast and plant cells are described that show that their plasma membrane is lateral... more Examples from yeast and plant cells are described that show that their plasma membrane is laterally compartmented. Distinct lateral domains encompassing both specific lipids and integral proteins coexist within the plane of the plasma membrane. The compartments are either spatially stable and include distinct sets of proteins, or they are transiently formed to accomplish diverse functions. They are not related to lipid rafts or their clusters, as defined for mammalian cells. This review summarises only well‐documented compartments of plasma membranes from plants and fungi, which have been recognised using microscopic approaches. In several cases, physiological functions of the membrane compartmentation are revealed.
Yeast, 2010
The plasma membrane of Saccharomyces cerevisiae contains large microdomains enriched in ergostero... more The plasma membrane of Saccharomyces cerevisiae contains large microdomains enriched in ergosterol, which house at least nine integral proteins, including proton symporters. The domains adopt a characteristic structure of furrow‐like invaginations typically seen in freeze‐fracture pictures of fungal cells. Being stable for the time comparable with the cell cycle duration, they might be considered as fixed islands (rafts) in an otherwise fluid yeast plasma membrane. Rapidly moving endocytic marker proteins avoid the microdomains; the domain‐accumulated proton symporters consequently show a reduced rate of substrate‐induced endocytosis and turnover. Copyright © 2010 John Wiley & Sons, Ltd.
Eukaryotic Cell, 2010
The plasma membrane of the yeast Saccharomyces cerevisiae contains stably distributed lateral dom... more The plasma membrane of the yeast Saccharomyces cerevisiae contains stably distributed lateral domains of specific composition and structure, termed MCC ( m embrane c ompartment of arginine permease C an1). Accumulation of Can1 and other specific proton symporters within MCC is known to regulate the turnover of these transporters and is controlled by the presence of another MCC protein, Nce102. We show that in an NCE102 deletion strain the function of Nce102 in directing the specific permeases into MCC can be complemented by overexpression of the NCE102 close homolog FHN1 (the previously uncharacterized YGR131W ) as well as by distant Schizosaccharomyces pombe homolog fhn1 ( SPBC1685.13 ). We conclude that this mechanism of plasma membrane organization is conserved through the phylum Ascomycota . We used a hemagglutinin (HA)/Suc2/His4C reporter to determine the membrane topology of Nce102. In contrast to predictions, its N and C termini are oriented toward the cytosol. Deletion of th...
Biochimica et Biophysica Acta (BBA) - Biomembranes, 2005
FEBS Letters, Feb 22, 2000
Biochimica Et Biophysica Acta - Biomembranes, May 1, 1981
The high pH-maintaining capacity of yeast suspension after glucose-induced acidification, measure... more The high pH-maintaining capacity of yeast suspension after glucose-induced acidification, measured as its ability to neutralize added alkali, was found to be due mainly to actively extruded acidity (H÷). The buffering action of passively excreted metabolites (CO2, organic acids) and cell surface polyelectrolytes contributed only 15--40% to the overall pH-maintaining capacity which was 10 mmol NaOH/1 per pH unit between pH 3 and 4 and 3.5 mmol NaOH/1 per pH unit between pH 4 and 7. The buffering capacity of yeast cell-free extract was still higher (up to 4.5-times) than that of glucose-supplied cell suspension; addition of glucose to the extract thus produced considerable titratable acidity but negligible net acidity. The glucose-induced acidification of yeast suspension was stimulated by univalent cations in the sequence K* :> Rb ÷ ~ Li ÷ -~ Cs ÷ -~ Na ÷. The processes participating in the acidification and probably also in the creation of extracellular buffering capacity include excretion of CO2 and organic acids, net extrusion of H ÷ and K ÷ (in K÷-free media; in K*~ontaining media this is preceded by an initial rapid K ÷ uptake), and movements of some anions (phosphate, chlorides). The overall process appears to be electrically silent.
European Journal of Cell Biology, Sep 1, 2017
Biochimica Et Biophysica Acta - Biomembranes, Feb 1, 2003
Plant Biology, Jun 7, 2010
Examples from yeast and plant cells are described that show that their plasma membrane is lateral... more Examples from yeast and plant cells are described that show that their plasma membrane is laterally compartmented. Distinct lateral domains encompassing both specific lipids and integral proteins coexist within the plane of the plasma membrane. The compartments are either spatially stable and include distinct sets of proteins, or they are transiently formed to accomplish diverse functions. They are not related to lipid rafts or their clusters, as defined for mammalian cells. This review summarises only well‐documented compartments of plasma membranes from plants and fungi, which have been recognised using microscopic approaches. In several cases, physiological functions of the membrane compartmentation are revealed.
Biochimica Et Biophysica Acta - Biomembranes, Aug 1, 2002
DOAJ (DOAJ: Directory of Open Access Journals), 2014
European journal of cell biology, Jan 3, 2017
We describe a novel mechanism of mRNA decay regulation, which takes place under the conditions of... more We describe a novel mechanism of mRNA decay regulation, which takes place under the conditions of glucose deprivation in the yeast Saccharomyces cerevisiae. The regulation is based on temporally stable sequestration of the main 5'-3' mRNA exoribonuclease Xrn1 at the eisosome, a plasma membrane-associated protein complex organizing a specialized membrane microdomain. As documented by monitoring the decay of a specific mRNA substrate in time, Xrn1-mediated mRNA degradation ceases during the accumulation of Xrn1 at eisosome, but the eisosome-associated Xrn1 retains its functionality and can be re-activated when released to cytoplasm following the addition of glucose. In cells lacking the eisosome organizer Pil1, Xrn1 does not associate with the plasma membrane and its activity is preserved till the stationary phase. Thus, properly assembled eisosome is necessary for this kind of Xrn1 regulation, which occurs in a liquid culture as well as in a differentiated colony.
International Review of Cell and Molecular Biology, 2016
The organization of biological membranes into structurally and functionally distinct lateral micr... more The organization of biological membranes into structurally and functionally distinct lateral microdomains is generally accepted. From bacteria to mammals, laterally compartmentalized membranes seem to be a vital attribute of life. The crucial fraction of our current knowledge about the membrane microdomains has been gained from studies on fungi. In this review we summarize the evidence of the microdomain organization of membranes from fungal cells, with accent on their enormous diversity in composition, temporal dynamics, modes of formation, and recognized engagement in the cell physiology. A special emphasis is laid on the fact that in addition to their other biological functions, membrane microdomains also mediate the communication among different membranes within a eukaryotic cell and coordinate their functions. Involvement of fungal membrane microdomains in stress sensing, regulation of lipid homeostasis, and cell differentiation is discussed more in detail.
The Journal of cell biology, Jan 15, 2008
In this study, we investigate whether the stable segregation of proteins and lipids within the ye... more In this study, we investigate whether the stable segregation of proteins and lipids within the yeast plasma membrane serves a particular biological function. We show that 21 proteins cluster within or associate with the ergosterol-rich membrane compartment of Can1 (MCC). However, proteins of the endocytic machinery are excluded from MCC. In a screen, we identified 28 genes affecting MCC appearance and found that genes involved in lipid biosynthesis and vesicle transport are significantly overrepresented. Deletion of Pil1, a component of eisosomes, or of Nce102, an integral membrane protein of MCC, results in the dissipation of all MCC markers. These deletion mutants also show accelerated endocytosis of MCC-resident permeases Can1 and Fur4. Our data suggest that release from MCC makes these proteins accessible to the endocytic machinery. Addition of arginine to wild-type cells leads to a similar redistribution and increased turnover of Can1. Thus, MCC represents a protective area wit...
Cellular and molecular biology, 1985
Plant Biology, 2010
Examples from yeast and plant cells are described that show that their plasma membrane is lateral... more Examples from yeast and plant cells are described that show that their plasma membrane is laterally compartmented. Distinct lateral domains encompassing both specific lipids and integral proteins coexist within the plane of the plasma membrane. The compartments are either spatially stable and include distinct sets of proteins, or they are transiently formed to accomplish diverse functions. They are not related to lipid rafts or their clusters, as defined for mammalian cells. This review summarises only well‐documented compartments of plasma membranes from plants and fungi, which have been recognised using microscopic approaches. In several cases, physiological functions of the membrane compartmentation are revealed.
Yeast, 2010
The plasma membrane of Saccharomyces cerevisiae contains large microdomains enriched in ergostero... more The plasma membrane of Saccharomyces cerevisiae contains large microdomains enriched in ergosterol, which house at least nine integral proteins, including proton symporters. The domains adopt a characteristic structure of furrow‐like invaginations typically seen in freeze‐fracture pictures of fungal cells. Being stable for the time comparable with the cell cycle duration, they might be considered as fixed islands (rafts) in an otherwise fluid yeast plasma membrane. Rapidly moving endocytic marker proteins avoid the microdomains; the domain‐accumulated proton symporters consequently show a reduced rate of substrate‐induced endocytosis and turnover. Copyright © 2010 John Wiley & Sons, Ltd.
Eukaryotic Cell, 2010
The plasma membrane of the yeast Saccharomyces cerevisiae contains stably distributed lateral dom... more The plasma membrane of the yeast Saccharomyces cerevisiae contains stably distributed lateral domains of specific composition and structure, termed MCC ( m embrane c ompartment of arginine permease C an1). Accumulation of Can1 and other specific proton symporters within MCC is known to regulate the turnover of these transporters and is controlled by the presence of another MCC protein, Nce102. We show that in an NCE102 deletion strain the function of Nce102 in directing the specific permeases into MCC can be complemented by overexpression of the NCE102 close homolog FHN1 (the previously uncharacterized YGR131W ) as well as by distant Schizosaccharomyces pombe homolog fhn1 ( SPBC1685.13 ). We conclude that this mechanism of plasma membrane organization is conserved through the phylum Ascomycota . We used a hemagglutinin (HA)/Suc2/His4C reporter to determine the membrane topology of Nce102. In contrast to predictions, its N and C termini are oriented toward the cytosol. Deletion of th...
Biochimica et Biophysica Acta (BBA) - Biomembranes, 2005