Direct Evidence of Lipid Rafts by in situ Atomic Force Microscopy
Direct Evidence of Lipid Rafts by in situ Atomic Force Microscopy
复制标题
原位原子力显微镜观察脂筏的直接证据
DOI：
10.1002/smll.201102183
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发表时间：
2012-04-23
期刊：
影响因子：
13.3
通讯作者：
Wang, Hongda
中科院分区：
文献类型：
--
作者：
Cai, Mingjun;Zhao, Weidong;Wang, Hongda
脂筏是富含胆固醇、鞘糖脂和蛋白质的膜微区。尽管人们普遍认为脂筏在细胞的各种功能中起着关键作用，但关于脂筏的组成、功能甚至是否存在仍存在激烈的争论。在这里，高分辨率和延时原位原子力显微镜被用来直接确认天然红细胞膜中脂筏的存在。结果表明，脂筏的一些重要特征是：脂筏大多数大小在100300 nm之间，形状不规则，抗洗涤剂膜由胆固醇微区组成，与脂筏不太一样，胆固醇对蛋白质微区的形成和稳定有重要作用，胆固醇的存在对脂筏的稳定性有重要影响。而Band Ⅲ是红细胞膜内叶脂筏的重要蛋白，说明脂筏正是红细胞膜的功能域。这项工作提供了直接证据的存在，大小和主要组成蛋白的脂筏在几个纳米的分辨率，这将铺平道路，详细研究其结构和功能。
Lipid rafts are membrane microdomains enriched with cholesterol, glycosphingolipids, and proteins. Although they are broadly presumed to play a pivotal role in various cellular functions, there are still fierce debates about the composition, functions, and even existence of lipid rafts. Here high-resolution and time-lapse in situ atomic force microscopy is used to directly confirm the existence of lipid rafts in native erythrocyte membranes. The results indicate some important aspects of lipid rafts: most of the lipid rafts are in the size range of 100300 nm and have irregular shape; the detergent-resistant membranes consist of cholesterol microdomains and are not likely the same as the lipid rafts; cholesterol contributes significantly to the formation and stability of the protein domains; and Band III is an important protein of lipid rafts in the inner leaflet of erythrocyte membranes, indicating that lipid rafts are exactly the functional domains in plasma membrane. This work provides direct evidence of the presence, size, and main constitutive protein of lipid rafts at a resolution of a few nanometers, which will pave the way for studying their structure and functions in detail.