Membrane Interactions of C2 Domains

蛋白质与细胞内膜界面的可逆结合对于调节细胞内蛋白质的表达是至关重要的。 膜运输和细胞信号传导途径。这种结合激活了酶，促进了蛋白质- 蛋白质相互作用，驱动蛋白质组装体的横向组织，并负责蛋白质的相互作用。 重塑细胞膜。它也被证明可以调节细胞转化和癌症。 膜结合通常由与膜相关的专门蛋白质结构域介导 界面响应特定的细胞信号;然而，关于膜的信息很少 这些领域的互动。拟议的工作将使用EPR为基础的技术称为网站- 定向自旋标记以确定这些结构域的膜取向和位置。的力量 还将评价驱动膜附着。突触结合蛋白的C2结构域介导钙离子- 依赖的神经元胞吐，以及它们在膜界面上的位置， 将测定磷脂酰肌醇-4，5-二磷酸（一种重要的信号脂质）。静电力 可能驱动信号复合物的组装，并且假设高正电荷蛋白质 将测试片段作为支架以螯合双层表面上的蛋白质。膜 两个磷酸肌醇结合结构域的位置也将被表征， 确定所评价的膜表面上的蛋白质取向和深度。 我们预计，更好地了解这些蛋白质膜相互作用将导致更好的 膜运输和细胞信号事件的理解。更好地了解这些事件 也可能导致控制细胞生长和癌症的新方法的发展。

The reversible binding of proteins to intracellular membrane interfaces is critical to the regulation of membrane trafficking and cell-signaling pathways. This association activates enzymes, facilitates protein- protein interactions, drives the lateral organization of protein assemblies and is responsible for the remodeling of cell membranes. It has also been shown to regulate cell-transformation and cancer. Membrane binding is often mediated by specialized protein domains that associate with the membrane interface in response to specific cellular signals; however, there is little information about the membrane interactions made by these domains. The proposed work will use an EPR based technique termed site- directed spin labeling to determine the membrane orientation and position of these domains. The forces that drive membrane attachment will also be evaluated. The C2 domains of synaptotagmin mediate calcium- dependent neuronal exocytosis, and their positions on the membrane interface in the presence of phosphatidylinositol-4,5-bisphosphate (an important signaling lipid) will be determined. Electrostatic forces may drive the assembly of signaling complexes, and the hypothesis that highly positively charged protein segments act as a scaffold to sequester proteins on the bilayer surface will be tested. The membrane position of two phosphoinositide binding domains will also be characterized and new approaches to determine protein orientation and depth on membrane surfaces evaluated. We anticipate that a better understanding of these protein-membrane interactions will lead to a better understanding of membrane trafficking and cell-signaling events. A better understanding of these events may also lead to the development of new approaches to control cell growth and cancer.