Membrane Interactions of C2 Domains

蛋白质与细胞膜界面的可逆结合对调节细胞膜运输和细胞信号通路至关重要。这种结合激活酶，促进蛋白质之间的相互作用，驱动蛋白质组装的横向组织，并负责细胞膜的重塑。它还被证明可以调节细胞转化和癌症。膜结合通常是由响应特定细胞信号与膜界面相关的特殊蛋白质结构域介导的；然而，关于这些结构域的膜相互作用的信息很少。提出的工作将使用一种基于EPR的技术，称为位点定向自旋标记，以确定这些结构域的膜方向和位置。驱动膜附着的力也将被评估。synaptotagmin的C2结构域介导钙依赖性

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.