MEMBRANE DYNAMICS IN NORMAL AND ABNORMAL RED BLOOD CELLS

人体红细胞膜是一个动态结构， 以确保细胞持续存活。 红细胞膜下细胞骨架在确定 红细胞稳定性、变形性和形状、性质，反过来， 影响红细胞和红细胞之间的相互作用 网状内皮系统 该提案侧重于一套动态的 细胞骨架控制的膜现象： 主要跨膜蛋白的分布和横向移动性 人类红细胞带3和血型糖蛋白。 这些现象将 在已用共价荧光标记的膜上进行检查 特异于条带3和/或血型糖蛋白的试剂，使用以下技术： 荧光显微术，荧光光漂白恢复，和 荧光能量转移 分子间的相互作用 3、血型糖蛋白和细胞骨架成分将被探测， 在各种动态控制机制中，例如空间位阻、特定的 结合和复合物形成。 固定化的机理 细胞内钙离子的升高导致细胞膜中的血型糖蛋白的升高， 其中钙调蛋白的可能作用也将被研究。 详细 正常和异常红细胞跨膜蛋白动力学研究 膜--例如来自遗传性球形红细胞增多症患者的膜， 遗传性椭圆形红细胞增多症、遗传性焦斑红细胞增多症和镰状细胞 贫血--有望提供有关结构的新信息， 红细胞膜在健康和疾病中的功能。 的改变 跨膜蛋白动力学可能例如不利地影响 红细胞和网状内皮系统细胞之间的相互作用， 导致异常粘附、隔离或溶血。 的目标 这项研究是从分子角度理解细胞骨架， 力的分布和横向迁移的跨膜 人红细胞膜中的蛋白质，以及 这些控制机制和疾病病理生理学的紊乱 各种异常的红细胞膜状态

The human red blood cell membrane is a dynamic structure which must respond to changes in its environment in order to assure continued cell viability. The submenbranous erythrocyte cytoskeleton plays a crucial role in defining red cell stability, deformability, and shape, properties which, in turn, influence interactions between the red cell and cells of the reticuloendothelial system. This proposal focuses on a set of dynamic membrane phenomena which are controlled by the cytoskeleton: the distribution and lateral mobility of the major transmembrane proteins of the human red blood cell -- band 3 and glycophorin. These phenomena will be examined on membranes which have been labeled with covalent fluorescent reagents specific for band 3 and/or glycophorin, using the techniques of fluorescence microscopy, fluorescence phtobleaching recovery, and fluorescence energy transfer. The intermolecular interactions among band 3, glycophorin, and cytoskeletal components will be probed, differentiating among various dynamic control mechanisms such as steric hindrance, specific binding, and complex formation. The mechanism of immobilization of glycophorin in the membrane by elevated intracellular calcium, and the possible role of calmodulin therein, will also be investigated. Detailed study of transmembrane protein dynamics in normal and abnormal erythrocyte membranes -- such as those from patients with hereditary spherocytosis, hereditary elliptocytosis, hereditary pyropoikilocytosis and sickle cell anemia -- is expected to provide new information about the structure and function of the red cell membrane in health and disease. Alterations in transmembrane protein dynamics may, for example, adversely affect interactions between red cells and cells of the reticuloendothelial system, leading to abnormal adherence, sequenstration, or hemolysis. The goal of this research is the understanding, in molecular terms, of the cytoskeletal forces controlllng the distribution and lateral mobility of transmembrane proteins in the human erythrocyte membrane, and of the relationship between derangements in these control mechanisms and the pathophysiology of disease in various abnormal red cell membrane states.