CELL SURFACE CONTROL OF LYMPHOCYTE PHYSIOLOGY

这项研究的目的是了解肌动蛋白如何与血浆相互作用。 薄膜。目前正在研究肌动蛋白-膜连接的三个例子。 (1)我们正在测定肌动蛋白对膜的分子组成 肠道微绒毛中的交叉丝。A)我们建议将 微绒毛110K蛋白，是交叉丝的候选蛋白，并 确定它是否以及如何与肌动蛋白和微绒毛相互作用 体外成膜。B)我们将测试微绒毛的拟议作用 核心蛋白(纤毛蛋白、绒毛蛋白、110K、肌动蛋白和钙调蛋白) 肌动蛋白细丝核心束的结构和膜结合 这些蛋白的免疫结构定位在原位，使用50 与50埃复合的单抗Fab‘片段 金粒。C)我们将筛选微绒毛蛋白 利用~3H-肌动蛋白的重构结合实验将肌动蛋白与膜结合， 微绒毛膜和分离的微绒毛蛋白。(2)我们是 纽蛋白样蛋白与血浆的相关性分析 薄膜。我们在平滑肌中发现了两种新的蛋白质，150K 偏纽蛋白和300K纽蛋白样多肽(300K-VLP)分别为 与130K纽蛋白有抗原性相关，但与纽蛋白不同，它有 两亲性膜蛋白的溶解性和可直接 连接肌动蛋白细丝和细胞膜。我们建议分析 抗原相似性和溶解性差异的分子基础 通过肽图谱、电荷转移电泳法 生物合成标记和脉冲追逐实验，分离原生生物 Metavinculin和300K-VLP及其与蛋白质相互作用的研究 肌动蛋白、质膜和脂质体的体外实验。(3)我们定义了一个单元格 免疫荧光法检测某些小鼠淋巴细胞表面肌动蛋白(CsA) 流式细胞术。A)我们建议用双色免疫荧光法测定 如果CsA是新的小鼠和人类淋巴细胞的标志，则进行流式细胞术 T细胞和B细胞已知亚群中的亚群。B)我们会 CsA与细胞内肌动蛋白生化差异的测定 确定CsA是否是糖蛋白以及它是否具有疏水结构域。 C)我们计划测试CsA在调节黏附过程中的可能功能 淋巴细胞对纤维连接蛋白和淋巴网内皮细胞的影响 系统，以及CsA作为细胞表面一部分的可能功能 生长控制复合体。

The objective of this research is to learn how actin interacts with plasma membrane. Three examples of actin-membrane linkages are being studied. (1) We are determining the molecular composition of the actin to membrane cross filament in intestinal microvilli. a) We propose to isolate the microvillar 110K protein, a candidate for the cross filament, and to determine whether and how it interacts with actin and the microvillar membrane in vitro. b) We will test the proposed roles of the microvillar core proteins (fimbrin, villin, 110K, actin, and calmodulin) in the structure and membrane association of the core bundle of actin filaments by immunoultrastructural localization of these proteins in situ, using 50 angstroms Fab' fragments of monoclonal antibodies complexed to 50 angstroms gold particles. c) We will screen for microvillar proteins which link actin to membrane by a reconstitution binding assay employing 3H-actin, microvillar membranes, and fractionated microvillar proteins. (2) We are analyzing the association of vinculin-like proteins with the plasma membrane. We have discovered two new proteins in smooth muscle, 150K meta-vinculin, and 300K vinculin-like polypeptide (300K-VLP) that are antigenically related to 130K vinculin, but which unlike vinculin, have solubility properties of amphiphilic membrane proteins and could be direct links between actin filaments and the cell membrane. We propose to analyze the molecular basis for the antigenic similarity and solubility difference between these proteins by peptide mapping, charge shift electrophoresis, biosynthetic labelling and pulse-chase experiments, isolation of native metavinculin and 300K-VLP and characterization of their interaction with actin, plasma membrane and liposomes in vitro. (3) We have defined a cell surface actin (CSA) on some murine lymphocytes by immunofluorescence and flow cytometry. a) We propose to determine by two-color immunofluorescence and flow cytometry if CSA is a marker for new murine and human lymphocyte subpopulations within the known subdivisions of T and B-cells. b) We will assay for biochemical differences between CSA and intracellular actin by determining if CSA is a glycoprotein and if it has a hydrophobic domain. c) We plan to test for the possible function of CSA in mediating adherence of lymphocytes to fibronectin and to cells of the lymphoreticuloendothelial system, and for the possible function of CSA as part of a cell surface growth control complex.