Lateral membrane compartments: Formation, functional relevance and genomics

越来越多的证据表明，流体镶嵌膜的辛格/尼科尔森模型可能需要修改。膜，尤其是质膜，似乎是横向亚区室。在酿酒酵母中，通过共聚焦激光扫描显微镜已经区分了两个隔室：一个是富含几个质子/底物共转运体以及麦角固醇，另一个容纳质膜H+-ATP酶。最近，我们已经证明，膜电位的影响这些蛋白质的区室化模式。- 计划在未来两年进行以下研究：A）应通过应用EM/免疫金检测来寻找蛋白质聚类。B）将研究不同结构域中的蛋白质迁移率。C）将筛选酵母缺失集合的突变体，其中GFP融合蛋白的分布-通常形成不同的模式-将被扰乱。D.功能调查：a）将均匀存在于膜中的共转运体（来自突变体筛选）的转运动力学与野生型细胞进行比较，其中它们形成典型的斑片状模式。B）将测试同向转运体区室与所谓的“异质体”的关系（Walther等，2006），以了解膜区室化是否与胞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.