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Influence of squalene on lipid particle/droplet and membrane organization in the yeast Saccharomyces cerevisiae

In a previous study (Spanova et al., 2010, J. Biol. Chem., 285, 6127–6133) we demonstrated that squalene, an intermediate of sterol biosynthesis, accumulates in yeast strains bearing a deletion of the HEM1 gene. In such strains, the vast majority of squalene is stored in lipid particles/droplets tog...

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Autores principales: Spanova, Miroslava, Zweytick, Dagmar, Lohner, Karl, Klug, Lisa, Leitner, Erich, Hermetter, Albin, Daum, Günther
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Elsevier Pub. Co 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3790963/
https://www.ncbi.nlm.nih.gov/pubmed/22342273
http://dx.doi.org/10.1016/j.bbalip.2012.01.015
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author Spanova, Miroslava
Zweytick, Dagmar
Lohner, Karl
Klug, Lisa
Leitner, Erich
Hermetter, Albin
Daum, Günther
author_facet Spanova, Miroslava
Zweytick, Dagmar
Lohner, Karl
Klug, Lisa
Leitner, Erich
Hermetter, Albin
Daum, Günther
author_sort Spanova, Miroslava
collection PubMed
description In a previous study (Spanova et al., 2010, J. Biol. Chem., 285, 6127–6133) we demonstrated that squalene, an intermediate of sterol biosynthesis, accumulates in yeast strains bearing a deletion of the HEM1 gene. In such strains, the vast majority of squalene is stored in lipid particles/droplets together with triacylglycerols and steryl esters. In mutants lacking the ability to form lipid particles, however, substantial amounts of squalene accumulate in organelle membranes. In the present study, we investigated the effect of squalene on biophysical properties of lipid particles and biological membranes and compared these results to artificial membranes. Our experiments showed that squalene together with triacylglycerols forms the fluid core of lipid particles surrounded by only a few steryl ester shells which transform into a fluid phase below growth temperature. In the hem1∆ deletion mutant a slight disordering effect on steryl esters was observed indicated by loss of the high temperature transition. Also in biological membranes from the hem1∆ mutant strain the effect of squalene per se is difficult to pinpoint because multiple effects such as levels of sterols and unsaturated fatty acids contribute to physical membrane properties. Fluorescence spectroscopic studies using endoplasmic reticulum, plasma membrane and artificial membranes revealed that it is not the absolute squalene level in membranes but rather the squalene to sterol ratio which mainly affects membrane fluidity/rigidity. In a fluid membrane environment squalene induces rigidity of the membrane, whereas in rigid membranes there is almost no additive effect of squalene. In summary, our results demonstrate that squalene (i) can be well accommodated in yeast lipid particles and organelle membranes without causing deleterious effects; and (ii) although not being a typical membrane lipid may be regarded as a mild modulator of biophysical membrane properties.
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spelling pubmed-37909632013-10-07 Influence of squalene on lipid particle/droplet and membrane organization in the yeast Saccharomyces cerevisiae Spanova, Miroslava Zweytick, Dagmar Lohner, Karl Klug, Lisa Leitner, Erich Hermetter, Albin Daum, Günther Biochim Biophys Acta Article In a previous study (Spanova et al., 2010, J. Biol. Chem., 285, 6127–6133) we demonstrated that squalene, an intermediate of sterol biosynthesis, accumulates in yeast strains bearing a deletion of the HEM1 gene. In such strains, the vast majority of squalene is stored in lipid particles/droplets together with triacylglycerols and steryl esters. In mutants lacking the ability to form lipid particles, however, substantial amounts of squalene accumulate in organelle membranes. In the present study, we investigated the effect of squalene on biophysical properties of lipid particles and biological membranes and compared these results to artificial membranes. Our experiments showed that squalene together with triacylglycerols forms the fluid core of lipid particles surrounded by only a few steryl ester shells which transform into a fluid phase below growth temperature. In the hem1∆ deletion mutant a slight disordering effect on steryl esters was observed indicated by loss of the high temperature transition. Also in biological membranes from the hem1∆ mutant strain the effect of squalene per se is difficult to pinpoint because multiple effects such as levels of sterols and unsaturated fatty acids contribute to physical membrane properties. Fluorescence spectroscopic studies using endoplasmic reticulum, plasma membrane and artificial membranes revealed that it is not the absolute squalene level in membranes but rather the squalene to sterol ratio which mainly affects membrane fluidity/rigidity. In a fluid membrane environment squalene induces rigidity of the membrane, whereas in rigid membranes there is almost no additive effect of squalene. In summary, our results demonstrate that squalene (i) can be well accommodated in yeast lipid particles and organelle membranes without causing deleterious effects; and (ii) although not being a typical membrane lipid may be regarded as a mild modulator of biophysical membrane properties. Elsevier Pub. Co 2012-04 /pmc/articles/PMC3790963/ /pubmed/22342273 http://dx.doi.org/10.1016/j.bbalip.2012.01.015 Text en © 2012 Elsevier B.V. https://creativecommons.org/licenses/by-nc-nd/3.0/ Open Access under CC BY-NC-ND 3.0 (https://creativecommons.org/licenses/by-nc-nd/3.0/) license
spellingShingle Article
Spanova, Miroslava
Zweytick, Dagmar
Lohner, Karl
Klug, Lisa
Leitner, Erich
Hermetter, Albin
Daum, Günther
Influence of squalene on lipid particle/droplet and membrane organization in the yeast Saccharomyces cerevisiae
title Influence of squalene on lipid particle/droplet and membrane organization in the yeast Saccharomyces cerevisiae
title_full Influence of squalene on lipid particle/droplet and membrane organization in the yeast Saccharomyces cerevisiae
title_fullStr Influence of squalene on lipid particle/droplet and membrane organization in the yeast Saccharomyces cerevisiae
title_full_unstemmed Influence of squalene on lipid particle/droplet and membrane organization in the yeast Saccharomyces cerevisiae
title_short Influence of squalene on lipid particle/droplet and membrane organization in the yeast Saccharomyces cerevisiae
title_sort influence of squalene on lipid particle/droplet and membrane organization in the yeast saccharomyces cerevisiae
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3790963/
https://www.ncbi.nlm.nih.gov/pubmed/22342273
http://dx.doi.org/10.1016/j.bbalip.2012.01.015
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