Lipid rafts are enriched in arachidonic acid and plasmenylethanolamine and their composition is independent of caveolin-1 expression: A quantitative electrospray ionization/mass spectrometric analysis
Lipid rafts are enriched in arachidonic acid and plasmenylethanolamine and their composition is independent of caveolin-1 expression: A quantitative electrospray ionization/mass spectrometric analysis
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DOI：
10.1021/bi0156557
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发表时间：
2002-02-12
期刊：
影响因子：
2.9
通讯作者：
Gross, RW
中科院分区：
文献类型：
--
作者：
Pike, LJ;Han, XL;Gross, RW
脂筏是一种特殊的富含胆固醇的膜结构域，参与细胞信号传递过程。小窝是由于结构蛋白小窝-1的存在而内陷的相关区域。在本文中，我们使用电喷雾电离质谱仪(ESI/MS)对表达和不表达小窝蛋白-1的细胞的质膜和非去污脂筏中的磷脂进行了定量比较。与质膜部分相比，脂筏富含胆固醇和鞘磷脂。小窝蛋白-1的表达增加了脂筏部分中回收的胆固醇的量，但不影响各种磷脂类别的相对比例。令人惊讶的是，ESI/MS表明，脂筏中富含血浆乙醇胺，特别是那些含有花生四烯酸的物质。而阴离子磷脂在质膜和非去污剂脂筏中的总含量相似，后者高度富含磷脂酰丝氨酸，而相对贫乏磷脂酰肌醇。由相同细胞制成的耐洗涤剂膜显示出比非洗涤剂脂筏更高的胆固醇含量，但阴离子磷脂被耗尽。此外，这些耐洗涤剂的膜没有富含花生四烯酸的乙醇胺血浆原。这些数据提供了对脂筏结构的洞察，并确定了这些结构域在信号转导中的潜在新角色。
Lipid rafts are specialized cholesterol-enriched membrane domains that participate in cellular signaling processes. Caveolae are related domains that become invaginated due to the presence of the structural protein, caveolin-1. In this paper, we use electrospray ionization mass spectrometry (ESI/MS) to quantitatively compare the phospholipids present in plasma membranes and nondetergent lipid rafts from caveolin-1-expressing and nonexpressing cells. Lipid rafts are enriched in cholesterol and sphingomyelin as compared to the plasma membrane fraction. Expression of caveolin-1 increases the amount of cholesterol recovered in the lipid raft fraction but does not affect the relative proportions of the various phospholipid classes. Surprisingly, ESI/MS demonstrated that lipid rafts are enriched in plasmenylethanolamines, particularly those containing arachidonic acid. While the total content of anionic phospholipids was similar in plasma membranes and nondetergent lipid rafts, the latter were highly enriched in phosphatidylserine but relatively depleted in phosphatidylinositol. Detergent-resistant membranes made from the same cells showed a higher cholesterol content than nondetergent lipid rafts but were depleted in anionic phospholipids. In addition, these detergent-resistant membranes were not enriched in arachidonic acid-containing ethanolamine plasmalogens. These data provide insight into the structure of lipid rafts and identify potential new roles for these domains in signal transduction.