Role of sterol structure in the thermotropic behavior of plasma membranes of Saccharomyces cerevisiae

Bottema, Cynthia D.K.; McLean-Bowen, Colleen A.; Parks, Leo W.

doi:10.1016/0005-2736(83)90121-9

Cited by 36 publications

(17 citation statements)

References 43 publications

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“…6b). In agreement with this, studies of phase transitions in isolated yeast plasma membranes are consistent with the existence of sterol-rich and sterol-poor phases (33). The high sterol and SL-to-PL ratio present in the plasma membrane of yeast is characteristic for specialized membranes that are exposed to the external environment and thus are under high stress, such as the apical membrane of epithelial cells (1).…”

Section: Discussionsupporting

confidence: 64%

Lipid rafts function in biosynthetic delivery of proteins to the cell surface in yeast

Bagnat

Keränen

Shevchenko

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

476

254

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Lipid rafts, formed by lateral association of sphingolipids and cholesterol, have been implicated in membrane traffic and cell signaling in mammalian cells. Sphingolipids also have been shown to play a role in protein sorting in yeast. Therefore, we wanted to investigate whether lipid rafts exist in yeast and whether these membrane microdomains have an analogous function to their mammalian counterparts. We first developed a protocol for isolating detergent-insoluble glycolipid-enriched complexes (DIGs) from yeast cells. Sequencing of the major protein components of the isolated DIGs by mass spectrometry allowed us to identify, among others, Gas1p, Pma1p, and Nce2p. Using lipid biosynthetic mutants we could demonstrate that conditions that impair the synthesis of sphingolipids and ergosterol also disrupt raft association of Gas1p and Pma1p but not the secretion of acid phosphatase. That endoplasmic reticulum (ER)-to-Golgi transport of Gas1p is blocked in the sphingolipid mutant lcb1-100 raised the question of whether proteins associate with lipid rafts in the ER or later as shown in mammalian cells. Using the sec18 -1 mutant we found that DIGs are present already in the ER. Taken together, our results suggest that lipid rafts are involved in the biosynthetic delivery of proteins to the yeast plasma membrane.

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Section: Discussionsupporting

confidence: 64%

Lipid rafts function in biosynthetic delivery of proteins to the cell surface in yeast

Bagnat

Keränen

Shevchenko

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

476

254

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“…Plasma membrane isolation. Plasma membranes were prepared and isolated by a modification of the procedure of Bottema et al (2). After a 5-min treatment with ,-mercaptoethanol buffer (0.5 M ,-mercaptoethanol, 0.1 M Tris, pH 9.3), cells were pelleted at 3,000 x g for 2 min.…”

Section: Methodsmentioning

confidence: 99%

Saccharomyces cerevisiae membrane sterol modifications in response to growth in the presence of ethanol

Walker-Caprioglio

Casey

Parks

1990

Appl Environ Microbiol

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Membranes isolated from yeasts grown in the presence of ethanol do not display the thermally induced transition in diphenylhexatriene anisotropy that is seen in control cells when they are exposed to ethanol in vitro. The total sterol content of the cells that were exposed to ethanol during growth is reduced, with no steryl esters being detected. A greater proportion of the total sterol pool is ergosterol in cells grown in the presence of alcohol. The activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase is reduced by ethanol in vitro. Ethanol-exposed cells take up more exogenous sterol under aerobic conditions than do control cells. The presence of ethanol during growth reduces the activity of the plasma membrane enzyme, chitin synthase, as well as increasing the thermosensitivity of this enzyme.

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“…These microdomains have been proposed to function in signaling (Kü bler et al, 1996); however, neither their lipid composition nor their role in internalization has been determined. Little evidence exists for sterol-rich and -poor regions in yeast plasma membranes (Bottema et al, 1983), nor is it known whether ergosterol can associate with sphingolipids to form lipid rafts (Leber et al, 1997). In animal cells, depletion of cholesterol prevents clustering of glycosylphosphatidylinositol-anchored proteins into lipid rafts and, thus, blocks their subsequent internalization (Chang et al, 1992;Rothberg et al, 1990;.…”

Section: Endocytosis Requires Specific Sterolsmentioning

confidence: 99%

Specific Sterols Required for the Internalization Step of Endocytosis in Yeast

Munn

Heese-Peck

Stevenson

et al. 1999

MBoC

155

186

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Sterols are major components of the plasma membrane, but their functions in this membrane are not well understood. We isolated a mutant defective in the internalization step of endocytosis in a gene (ERG2) encoding a C-8 sterol isomerase that acts in the late part of the ergosterol biosynthetic pathway. In the absence of Erg2p, yeast cells accumulate sterols structurally different from ergosterol, which is the major sterol in wild-type yeast. To investigate the structural requirements of ergosterol for endocytosis in more detail, several erg mutants (erg2Delta, erg6Delta, and erg2Deltaerg6Delta) were made. Analysis of fluid phase and receptor-mediated endocytosis indicates that changes in the sterol composition lead to a defect in the internalization step. Vesicle formation and fusion along the secretory pathway were not strongly affected in the ergDelta mutants. The severity of the endocytic defect correlates with changes in sterol structure and with the abundance of specific sterols in the ergDelta mutants. Desaturation of the B ring of the sterol molecules is important for the internalization step. A single desaturation at C-8,9 was not sufficient to support internalization at 37 degrees C whereas two double bonds, either at C-5,6 and C-7,8 or at C-5,6 and C-8,9, allowed internalization.

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Role of sterol structure in the thermotropic behavior of plasma membranes of Saccharomyces cerevisiae

Cited by 36 publications

References 43 publications

Lipid rafts function in biosynthetic delivery of proteins to the cell surface in yeast

Lipid rafts function in biosynthetic delivery of proteins to the cell surface in yeast

Saccharomyces cerevisiae membrane sterol modifications in response to growth in the presence of ethanol

Specific Sterols Required for the Internalization Step of Endocytosis in Yeast

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