Contribution of Are1p and Are2p to steryl ester synthesis in the yeast <i>Saccharomyces cerevisiae</i>

Zweytick, Dagmar; Leitner, Erich; Kohlwein, Sepp D.; Yu, Chunjiang; Rothblatt, Jonathan; Daum, GÃ1⁄4nther

doi:10.1046/j.1432-1327.2000.01103.x

Cited by 167 publications

(186 citation statements)

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“…The question, however, remained whether terbinafine sensitivity was because of the total block of STE synthesis, the decreased level of Erg1p in the quadruple mutant, or the lack of TAG and/or lipid particles in the quadruple mutant. Slightly increased sensitivity of the are1are2 double mutant against terbinafine has been reported before by Zweytick et al (4), although only at a drug concentration of 30 g/ml. Thus, it appears that hypersensitivity of dga1lro1are1are2 against terbinafine results from a combination of the low amount of Erg1p present in this mutant and the loss of TAG and/or lipid particles.…”

Section: Formation Of Lipid Particles Can Be Restored In a Dga1lro1arsupporting

confidence: 57%

A Yeast Strain Lacking Lipid Particles Bears a Defect in Ergosterol Formation

Sorger

Athenstaedt

Hrastnik

et al. 2004

Journal of Biological Chemistry

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115

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Lipid particles of the yeast Saccharomyces cerevisiae are storage compartments for triacylglycerols (TAG) and steryl esters (STE). Four gene products, namely the TAG synthases Dga1p and Lro1p, and the STE synthases Are1p and Are2p contribute to storage lipid synthesis. A yeast strain lacking the four respective genes is devoid of lipid particles thus providing a valuable tool to study the physiological role of storage lipids and lipid particles. Using a dga1lro1are1are2 quadruple mutant transformed with plasmids bearing inducible DGA1, LRO1, or ARE2 we demonstrate that TAG synthesis contributes more efficiently to lipid particle proliferation than synthesis of STE. Moreover, we show that proteins typically located to lipid particles in wild type such as Erg1p, Erg6p, Erg7p, and Ayr1p are refined to microsomal fractions of the dga1lro1are1are2 quadruple mutant. This result confirms the close relationship between lipid particles and endoplasmic reticulum. Most interestingly, the amount of the squalene epoxidase Erg1p, which is dually located in lipid particles and endoplasmic reticulum of wild type, is decreased in the quadruple mutant, whereas amounts of other lipid particle proteins tested were not reduced. This decrease is not caused by downregulation of ERG1 transcription but by the low stability of Erg1p in the quadruple mutant. Because a similar effect was also observed in are1are2 mutants this finding can be mainly attributed to the lack of STE. The quadruple mutant, however, was more sensitive to terbinafine, an inhibitor of Erg1p, than the are1are2 strain suggesting that the presence of TAG and/or intact lipid particles has an additional protective effect. In a strain lacking the two STE synthases, Are1p and Are2p, incorporation of ergosterol into the plasma membrane was reduced, although the total cellular amount of free ergosterol was higher in the mutant than in wild type. Thus, an esterification/deacylation mechanism appears to contribute to the supply of ergosterol to the plasma membrane.Triacylglycerols (TAG) 1 and steryl esters (STE) are the most important storage lipids in eukaryotic cells. TAG provides an energy source on one hand and a source of fatty acids for membrane phospholipid formation on the other hand. Mobilization of STE sets sterols free, which are also required for membrane proliferation, especially of the plasma membrane. In the yeast Saccharomyces cerevisiae as in other eukaryotic cells TAG and STE form the core of so called lipid particles (1), which are surrounded by a phospholipid monolayer with a small amount and a limited number of proteins embedded. Thus, formation of lipid particles is tightly linked to the synthesis of TAG and STE.In the yeast, ARE1 and ARE2 encode two enzymes with overlapping acyl-CoA:sterol acyltransferase activities (2, 3). Zweytick et al. (4) demonstrated that both proteins are located to the same subcellular compartment, namely the endoplasmic reticulum, but exhibit different specificities for sterol substrates in vivo. Both enzymes share 16 -17% amino...

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Section: Formation Of Lipid Particles Can Be Restored In a Dga1lro1arsupporting

confidence: 57%

A Yeast Strain Lacking Lipid Particles Bears a Defect in Ergosterol Formation

Sorger

Athenstaedt

Hrastnik

et al. 2004

Journal of Biological Chemistry

Self Cite

115

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“…The MLDP forms a proteinaceous coat surrounding mature LDs. The characterization of LD proteins has been reported in terrestrial oil seed plants and in certain mammalian tissues (Zweytick et al, 2000;Murphy et al, 2001). Downregulation of MLDP through RNA interference affects LD size without any compromise in the TAG level or its metabolism in Chlamydomonas reinhardtii (Moellering and Benning, 2010).…”

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confidence: 99%

Major Lipid Body Protein: A Conserved Structural Component of Lipid Body Accumulated during Abiotic Stress in S. quadricauda CASA-CC202

et al. 2016

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Abiotic stress in oleaginous microalgae enhances lipid accumulation, which is stored in a specialized organelle called lipid droplets (LDs). Both the LDs or lipid body are enriched with major lipid droplet protein (MLDP). It serves as a major structural component and also plays a key role in recruiting other proteins and enzymes involved in lipid body maturation. In the present study, the presence of MLDP was detected in two abiotic stress condition namely nitrogen starvation and salt stress condition. Previous research reveals that nitrogen starvation enhances lipid accumulation. Therefore, the effect of salt on growth, biomass yield, and fatty acid profile is studied in detail. The specific growth rate of Scenedesmus quadricauda under the salt stress of 10mM concentration is about 0.174 μ and in control, the SGR is 0.241 μ. An increase in the doubling time of the cells shows that the rate of cell division decreases during salt stress (2.87-5.17). The dry biomass content also decreased drastically at 50mM salt-treated cells (129 mg/L) compared to control (236 mg/L) on the day 20. The analysis of fatty acid composition also revealed that there is a 20% decrease in the saturated fatty acid level and 19.9% increment in monounsaturated fatty acid level, which makes salt-mediated lipid accumulation as a suitable biodiesel precursor.

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“…SE of S. cerevisiae are synthesized by two acyl-CoA:sterol acyltransferases named Are1p and Are2p (17), two closely related enzymes located to the ER. Are1p and Are2p exhibit slight differences in their substrate specificities (18). The major SE synthase Are2p preferentially utilizes ergosterol as a substrate, whereas Are1p esterifies ergosterol precursors, mainly lanosterol, as well.…”

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confidence: 99%

Regulation of the Yeast Triacylglycerol Lipase Tgl3p by Formation of Nonpolar Lipids

Schmidt

Athenstaedt

Koch

et al. 2013

Journal of Biological Chemistry

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Background: Tgl3p from yeast serves as the major triacylglycerol lipase but also as lysophospholipid acyltransferase. Results: Formation of nonpolar lipids strongly affects subcellular localization and function of Tgl3p. Conclusion: Tgl3p activity is mainly regulated by the presence/absence of lipid droplets. Significance: The yeast lipase/acyltransferase Tgl3p is an important player in lipid homeostasis.

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Contribution of Are1p and Are2p to steryl ester synthesis in the yeast Saccharomyces cerevisiae

Cited by 167 publications

References 35 publications

A Yeast Strain Lacking Lipid Particles Bears a Defect in Ergosterol Formation

A Yeast Strain Lacking Lipid Particles Bears a Defect in Ergosterol Formation

Major Lipid Body Protein: A Conserved Structural Component of Lipid Body Accumulated during Abiotic Stress in S. quadricauda CASA-CC202

Regulation of the Yeast Triacylglycerol Lipase Tgl3p by Formation of Nonpolar Lipids

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