Department of Environmental and Life Sciences, Toyohashi University of Technology, Toyohashi, Aichi, 441-8580, Japan.
Electronics-Inspired Interdisciplinary Research Institute, Toyohashi University of Technology, Toyohashi, Aichi, 441-8580, Japan.
Sci Rep. 2017 Dec 20;7(1):17905. doi: 10.1038/s41598-017-18242-9.
The lipid bilayer environment around membrane proteins strongly affects their structure and functions. Here, we aimed to study the fusion of proteoliposomes (PLs) derived from cultured cells with an artificial lipid bilayer membrane and the distribution of the PL components after the fusion. PLs, which were extracted as a crude membrane fraction from Chinese hamster ovary (CHO) cells, formed isolated domains in a supported lipid bilayer (SLB), comprising phosphatidylcholine (PC), phosphatidylethanolamine (PE), and cholesterol (Chol), after the fusion. Observation with a fluorescence microscope and an atomic force microscope showed that the membrane fusion occurred selectively at microdomains in the PC + PE + Chol-SLB, and that almost all the components of the PL were retained in the domain. PLs derived from human embryonic kidney 293 (HEK) cells also formed isolated domains in the PC + PE + Chol-SLB, but their fusion kinetics was different from that of the CHO-PLs. We attempted to explain the mechanism of the PL-SLB fusion and the difference between CHO- and HEK-PLs, based on a kinetic model. The domains that contained the whole cell membrane components provided environments similar to that of natural cell membranes, and were thus effective for studying membrane proteins using artificial lipid bilayer membranes.
脂质双层环境强烈影响膜蛋白的结构和功能。在这里，我们旨在研究来源于培养细胞的蛋白脂质体（PL）与人工脂质双层膜的融合，以及融合后 PL 成分的分布。PL 是从中国仓鼠卵巢（CHO）细胞粗膜部分提取的，在融合后，在含有卵磷脂（PC）、磷脂酰乙醇胺（PE）和胆固醇（Chol）的支持脂质双层（SLB）中形成独立的域。荧光显微镜和原子力显微镜的观察表明，膜融合选择性地发生在 PC+PE+Chol-SLB 的微域中，并且 PL 的几乎所有成分都保留在该域中。来源于人胚肾 293 细胞（HEK）的 PL 也在 PC+PE+Chol-SLB 中形成独立的域，但它们的融合动力学与 CHO-PLs 不同。我们试图根据动力学模型解释 PL-SLB 融合的机制以及 CHO 和 HEK-PLs 之间的差异。包含整个细胞膜成分的域提供了类似于天然细胞膜的环境，因此对于使用人工脂质双层膜研究膜蛋白非常有效。
