State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, PR China.
Small. 2012 Apr 23;8(8):1243-50. doi: 10.1002/smll.201102183. Epub 2012 Feb 20.
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 100-300 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.
脂质筏是富含胆固醇、糖脂和蛋白质的膜微区。尽管它们被广泛认为在各种细胞功能中起着关键作用，但关于脂质筏的组成、功能，甚至存在，仍然存在激烈的争论。本文采用高分辨率和实时原子力显微镜原位技术直接证实了天然红细胞膜中脂质筏的存在。结果表明了脂质筏的一些重要方面：大多数脂质筏的大小在 100-300nm 之间，形状不规则；去污剂抗性膜由胆固醇微区组成，与脂质筏可能不同；胆固醇对蛋白质域的形成和稳定性有重要贡献；Band III 是红细胞膜内层脂质筏的重要蛋白质，表明脂质筏正是质膜的功能域。这项工作提供了存在、大小和主要组成蛋白的直接证据，分辨率达到几个纳米，这将为详细研究它们的结构和功能铺平道路。
