Structures and dynamics of glycosphingolipid-containing lipid mixtures as raft models of plasma membrane
Structures and dynamics of glycosphingolipid-containing lipid mixtures as raft models of plasma membrane
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DOI：
10.1088/0953-8984/17/31/025
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发表时间：
2005-08-10
影响因子：
2.7
通讯作者：
Kasahara, K
中科院分区：
文献类型：
--
作者：
Hirai, M;Koizumi, M;Kasahara, K
哺乳动物质膜微结构域（筏）的结构和功能是细胞生物学的热门话题之一，因为这些结构域参与了重要的膜相关事件，特别是在生理和免疫学研究中经常看到的信号转导等事件。尽管积累了大量的证据，但关于膜的结构和动力学的物理性质，如完整细胞中的膜的物理性质的结果并不丰富。在本报告中，我们处理鞘脂（神经节苷脂）-胆固醇和鞘脂（神经节苷脂）-胆固醇-磷脂混合物的结构和动力学，用作筏和质膜模型。目前的结果清楚地表明，胆固醇与神经节苷脂聚集体的结合被限制在神经节苷脂与胆固醇的摩尔比的最大混溶范围内，范围从类似的1/1到1/3，形成直径约为250-300埃的小泡。这些摩尔比和大小与报道的组成比和筏的最小尺寸一致。在含有神经节苷脂、胆固醇和磷脂（PC、dsc、DOPC、POPC）的囊泡系统中，当[gang] / [chol] /[磷脂]的摩尔比= 0.1/0.1/1时，弯曲模量趋向于取最小值。目前的结果将有力地支持筏模型的功能物理特性：鞘脂和胆固醇聚集形成筏，在流体脂双分子层内移动。
The structure and function of mammalian plasma membrane microdomains, so-called rafts, are among the hot topics in cell biology, since it is suggested that these domains are involved in important membrane-associated events, especially ones such as signal transduction, which were frequently seen in physiological and immunological studies. In spite of the accumulation of large amounts of evidence, results on physical properties of the structure and dynamics of membranes such as those in intact cells are less abundant. In this report we treat the structure and dynamics of glycosphingolipid (ganglioside)-cholesterol and glycosphingolipid (ganglioside)-cholesterol-phospholipid mixtures used as models of rafts and plasma membranes. The present results clearly show that the incorporation of cholesterol with ganglioside aggregates is limited to a maximum miscibility of the molar ratio between the ganglioside and cholesterol ranging from similar to 1/1 to 1/3 and that small vesicles with diameters of about 250-300 angstrom form. These molar ratios and sizes agree well with the reported constituent ratio and minimum size for the rafts. In the vesicle systems containing ganglioside, cholesterol, and phospholipid (PC, DSPC, DOPC, POPC), the bending modulus tends to take the smallest value at the molar ratio of [gang] / [chol] / [phospholipid] = 0.1/0.1/1. The present results would strongly support a functional physical property of the raft model: sphingolipids and cholesterol clustering to form rafts that move within the fluid lipid bilayer.