REGULATION OF P55/HDLG INTERACTION WITH PROTEIN 4.1

P55是一种棕榈酰化的人红外周膜磷蛋白 血细胞。P55与蛋白质4.1和血糖蛋白C形成复合体。 这种蛋白质复合体在遗传异常的红细胞中缺失 形状发生改变，膜的稳定性明显降低。尽管 P55的确切生理作用尚不清楚，对此组件感兴趣 由于它与果蝇椎间盘--大肿瘤--的相似性而得到加强 抑制蛋白。P55和最近克隆的Hdlg(人B淋巴细胞 大果蝇的同源物)是一个不断增长的家族的成员 被认为在信号传递过程中发挥作用的称为MAGUK的蛋白质 膜-细胞骨架界面的转导。在这个项目中，我们 希望研究人p55和hdlg与细胞骨架的相互作用 蛋白4.1，并确定这些相互作用是否受 鸟嘌呤核苷酸和磷酸化。这些项目的长期目标是 研究的目的是检验MAGUK和MAGUK之间的相互作用 蛋白质4.1的同源物广泛存在，具有重要的生理意义。 使用这个项目中开发的蛋白质结合分析，我们将确定 如果其他MAGUK，如果蝇DLG，紧密连接Z0-1和线虫 LIN-2蛋白也与蛋白4.1结合。与Dr. Anderson，我们将测试P55和Hdlg的酪氨酸磷酸化 在哺乳动物细胞系统中发生在His 实验室。综上所述，MAGUK与蛋白质4.1之间的相互作用 可能成为信号转导的一般重要部位，并 膜-细胞骨架联动。

p55 is a palmitoylated peripheral membrane phosphoprotein of human red blood cells. p55 forms a complex with protein 4.1 and glycophorin C. This protein complex is missing in genetically abnormal red blood cells with altered shape and markedly reduced membrane stability. Although the precise physiological role of p55 is unknown, interest in this component has been heightened by its similarity to the Drosophila discs-large tumor suppressor protein. p55 and recently cloned Hdlg (human B lymphocyte homologue of the Drosophila discs-large) are members of a growing family of proteins called MAGUKs which are believed to play a role during signal transduction at the membrane-cytoskeleton interface. In this project, we wish to study the interaction of human p55 and Hdlg with cytoskeletal protein 4.1, and determine whether these interactions are regulated by guanine nucleotides and phosphorylation. The long-term goal of these studies is to test the hypothesis that interaction between MAGUKs and protein 4.1 homologues are widespread and physiologically important. Using protein binding assays developed in this project, we will determine if other MAGUKs such as Drosophila Dlg, tight junction Z0-1 and C. elegans LIN-2 proteins also bind to protein 4.1. In collaboration with Dr. Anderson, we will test whether tyrosine phosphorylation of p55 and Hdlg occurs in mammalian cell systems under the conditions developed in his laboratory. In summary, the interactions between MAGUKs and protein 4.1 may emerge as a generally important site for signal transduction and membrane-cytoskeleton linkage.