Roes Stefanie, Mumm Florian, Seydel Ulrich, Gutsmann Thomas
Research Center Borstel, Leibniz-Center for Medicine and Biological Sciences, Division of Biophysics, Parkallee 10, Borstel 23845, Germany.
J Biol Chem. 2006 Feb 3;281(5):2757-63. doi: 10.1074/jbc.M507634200. Epub 2005 Nov 21.
Lipopolysaccharides (LPS; endotoxin) activate immunocompetent cells of the host via a transmembrane signaling process. In this study, we investigated the function of the LPS-binding protein (LBP) in this process. The cytoplasmic membrane of the cells was mimicked by lipid liposomes adsorbed on mica, and the lateral organization of LBP in these membranes and its interaction with LPS aggregates were characterized by atomic force microscopy. Using cantilever tips functionalized with anti-LBP antibodies, single LBP molecules were localized in the membrane at low concentrations. At higher concentrations, LBP formed clusters of several molecules and caused cross-linking of lipid bilayers. The addition of LPS to LBP-containing liposomes led to the formation of LPS domains in the membranes, which could be inhibited by anti-LBP antibodies. Thus, LBP mediates the fusion of lipid membranes and LPS aggregates.
脂多糖（LPS；内毒素）通过跨膜信号传导过程激活宿主的免疫活性细胞。在本研究中，我们研究了LPS结合蛋白（LBP）在此过程中的功能。细胞的细胞质膜由吸附在云母上的脂质脂质体模拟，通过原子力显微镜表征了LBP在这些膜中的侧向组织及其与LPS聚集体的相互作用。使用用抗LBP抗体功能化的悬臂尖端，单个LBP分子在低浓度下定位在膜中。在较高浓度下，LBP形成几个分子的簇并导致脂质双层的交联。向含LBP的脂质体中添加LPS导致膜中形成LPS结构域，这可被抗LBP抗体抑制。因此，LBP介导脂质膜和LPS聚集体的融合。
