Lateral membrane compartments: Formation, functional relevance and genomics

越来越多的证据表明，流体镶嵌膜的Singer/Nicholson模型可能需要修改。膜，尤其是质膜，似乎是侧向的亚室。在酿酒酵母中，激光共聚焦扫描显微镜观察到两个隔室：一个富含多种质子/底物共转运体和麦角甾醇，另一个富含质膜H+-ATPase。最近，我们已经证明了膜电位影响其中一些蛋白质的区隔模式。-计划在未来两年进行以下调查：a)应用EM/免疫金检测寻找蛋白质聚集性。B)研究蛋白质在不同结构域中的迁移率。C)将对酵母缺失集合进行筛选，以寻找突变体，其中GFP融合蛋白的分布将受到干扰--通常形成不同的模式。D)功能研究：a)(来自突变筛选的)均匀存在于细胞膜中的共转运子的运输动力学将与野生型细胞进行比较，在野生型细胞中形成典型的斑片状模式。B)将测试转运蛋白隔室与所谓的“嗜酸性小体”的关系(Walther等人，2006年)，以确定膜隔室是否与内吞作用和蛋白质周转有关。

Evidence is accumulating that the Singer/Nicholson model of fluid mosaic membranes may have to be modified. Membranes, especially the plasma membrane, seem to be laterally subcompartmented. In Saccharomyces cerevisiae two compartments have been distinguished by confocal laser scanning microscopy: one is enriched in several proton/substrate symporters as well as in ergosterol, the other one houses the plasma membrane H+-ATPase. Recently, we have demonstrated that the membrane potential influences the compartmentation pattern of some of these proteins. – The following investigations are planned for the next two years: A) Protein clustering shall be looked for by applying EM/immuno-gold detection. B) The protein mobility in the various domains will be studied. C) The yeast deletion collection will be screened for mutants, in which the distribution of GFP-fusion proteins – normally forming distinct patterns – will be disturbed. D) Functional investigations: a)Transport kinetics of symporters homogenously present in the membrane (from the mutant screen) will be compared with wild type cells, where they form the typical patchy pattern. b) The relation of the symporter compartment to the so-called “eisosomes” (Walther et al, 2006) will be tested to see, whether membrane compartmentation is related to endocytosis and protein turnover.