Membrane shape transition control in cellular membrane trafficking phenomena

细胞膜转运现象中的膜形态转变控制 托拜厄斯·鲍姆加特，派 项目总结 膜的形状不仅是细胞和细胞器大小和结构的一个静态方面，而且 在许多过程中动态变化，如膜信号和运输。在血浆中 膜，在内吞作用和产生内分泌等过程中形成内排出物。 丝状伪足分别是膜曲率被调节的一些最重要的现象。 一类含有新月形支架的蛋白质的发现 (bin/两性蛋白/RVS)结构域蛋白，引起了人们对了解蛋白质如何结合的日益增长的兴趣 有膜的曲率。在许多与人类疾病有关的蛋白质中都发现了BAR结构域，并且 许多含有致病突变和/或在病理条件下表现出改变的表达水平。 与膜弯曲有关的其他外周蛋白包括固有的无序蛋白 如α-突触核蛋白，以及含有第10结构域蛋白质，如Eepsin，这两者都被认为是 卷入了膜贩运现象。 内吞作用是病原体进入细胞的主要机制。提高对……的认识 因此，这一过程的机制和调节是一个与生物医学相关的问题。然而， 尽管有90000多项研究成果仅研究了内吞作用，但 启动这一进程的机制尚不清楚。这在一定程度上是因为在细胞中 许多内吞机制并行运行，这是实验控制程度的关键 单元格中的参数是有限的。这个项目的目标是了解膜的形状转变是如何 在内吞作用等过程中被调节。为了实现这一目标，我们开发了一种实验性的 生物物理模型膜方法，使我们能够确定膜在什么条件下 经历形状转变。在这个工具的帮助下，它包括一个组合的微型 目前仅在我们实验室使用的操纵/荧光方法，我们将调查 许多参与内吞作用的蛋白质的作用机制，并分离关键的调节因子 膜的形状转变。我们已经开发了一个理论框架，将有助于 对我们的发现进行机械的解释。 而质膜在跨膜离子和脂质方面表现出显著的不对称性 在分布上，模型膜的研究主要集中在对称膜上。我们会克服这一点的 限制和确定膜不对称的程度，这将包括细胞骨架相互作用， 有助于外周蛋白在成膜过程中发挥作用。总体而言，该项目将提供远- 深入了解外周蛋白在健康和健康状态下变形细胞膜的机制 病理情况。

Membrane shape transition control in cellular membrane trafficking phenomena Tobias Baumgart, PI PROJECT SUMMARY Membrane shape is important not only as a static aspect of size and structure of cells and organelles, but dynamically changes in numerous processes such as membrane signaling and trafficking. At the plasma membrane, the formation of in- and exvaginations, in processes such as endocytosis and the generation of filopodia, respectively, are some of the most important phenomena where membrane curvature is modulated. The discovery of a class of proteins which contain crescent shaped scaffolds called BAR (Bin/amphiphysin/Rvs) domain proteins, has prompted a growing interest in understanding how proteins couple with membrane curvature. BAR domains are found in numerous proteins implicated in human disease, and many contain disease driving mutations and/or show altered expression levels under pathological conditions. Additional peripheral proteins that are related to membrane curvature include intrinsically disordered proteins such as α-synuclein, as well as ENTH domain-containing proteins such as epsin, both of which are believed to be involved in membrane trafficking phenomena. Endocytosis is the primary mechanism by which pathogens enter cells. To improve the understanding of the mechanism and regulation of this process therefore is a matter of primary biomedical relevance. However, despite the fact that more than 90000 research contributions have investigated endocytosis alone, the mechanisms for initiation of this process are not understood. This is due in part to the fact that in cells numerous endocytic mechanisms operate in parallel and that the degree for experimental control of key parameters in cells is limited. The goal of this project is to understand how membrane shape transitions are regulated in processes such as endocytosis. In order to achieve this goal, we have developed an experimental biophysical model membrane approach that allows us to determine the conditions under which membranes undergo shape transitions. With the help of this tool, which consists of a combined micro- manipulation/fluorescence approach that is presently used exclusively in our laboratory, we will investigate mechanisms of the function of the many proteins involved in endocytosis, and isolate key modulators of membrane shape transitions. We already have developed a theoretical framework that will facilitate mechanistic interpretation of our findings. While plasma membranes experience significant asymmetry with respect to transmembrane ion and lipid distributions, model membrane research has largely focused on symmetric membranes. We will overcome this limitation and determine to what extent membrane asymmetry, which will include cytoskeletal interactions, contributes to the function of peripheral proteins in shaping membranes. Overall this project will provide far- reaching insight into the mechanisms by which peripheral proteins deform membranes under healthy and pathological conditions.