CYTOSKELETON-MEMBRANE INTERACTIONS

对形态发生、伤口愈合、 病毒式转变取决于对基本知识的理解 细胞运动、细胞形状的维持和改变等细胞过程， 细胞-细胞和细胞-底物附着。在我们无知的核心 关于这些基本的生命过程是缺乏关于分子的知识 细胞骨架与细胞之间跨膜相互作用的细节 浮出水面。细胞粘菌的阿米巴阶段，Dictyostelius 盘状藻很容易大量生长，活动能力强，而且可以展示。 细胞-细胞以及细胞-底物的附着。利用盘藻作为一种 模型，我正在研究细胞之间的相互作用 这种细胞的质膜及其胞质细胞骨架蛋白。在……里面 在过去的三年里，我们将细胞-细胞接触区域从 聚合阿米巴，并开发了两种新的低速沉积 结合试验，以监测肌动蛋白和膜之间的联系。我们 发现整体蛋白调节特定的、可饱和的血浆结合 膜连接到肌动蛋白细丝的侧面，质膜可以 在膜表面甚至在肌动蛋白处催化肌动蛋白的聚合 浓度远低于正常的临界浓度 聚合反应。利用洗涤剂增溶和F-肌动蛋白亲和力 通过层析，我们已经鉴定出一个完整的肌动蛋白结合蛋白 表观分子量为17,000道尔顿。眼前的目标是 用化学方法鉴定和重组17kd的蛋白质 用交联法鉴定缺失的洗涤剂敏感肌动蛋白结合蛋白 用F-肌动蛋白亲和层析法制备单特异性抗体 抗变形体膜的主要整体膜组分 细胞骨架，以探索跨膜的结构和调节 在这个系统中的联系，并确定结构上是否相似 在其他物种中也发现了联系。最有价值的是分子 运动性以及细胞-细胞和细胞-底物相互作用的基础。

A complete understanding of phenomena such as morphogenesis, wound healing, and viral transformation is contingent upon an understanding of fundamental cell processes such as motility, the maintenance and change of cell shape, and cell-cell and cell-substrate attachment. At the core of our ignorance about these basic life processes is a lack of knowledge about the molecular details of transmembrane interactions between the cytoskeleton and the cell surface. The ameboid stage of the cellular slime mold, Dictyostelium discoideum is easily grown in large quantities, is motile, and exhibits cell-cell as well as cell-substrate attachment. Using D. discoideum as a model for cells in general, I am investigating the interactions between this cell's plasma membrane and its cytoplasmic cytoskeletal proteins. In the past three years we have isolated cell-cell contact regions from aggregated amebae, and have developed two new low-speed sedimentation binding assays to monitor associations between actin and membranes. We find that integral proteins mediate a specific, saturable binding of plasma membranes to the sides of actin filaments and that plasma membranes can catalyze the polymerization of actin at the membrane surface even at actin concentrations well below the normal critical concentration for polymerization. Using detergent solubilization and F-actin affinity chromatography, we have identified an integral actin-binding protein with an apparent molecular weight of 17,000 daltons. The immediate goals are to characterize and reconstitute the 17kd protein, to use chemical crosslinking to identify detergent-sensitive actin-binding proteins missed by F-actin affinity chromatography, to prepare monospecific antibodies against the major integral membrane components of an ameboid membrane cytoskeleton, to explore the structure and regulation of the transmembrane linkages in this system, and to determine whether structurally similar linkages are found in other species. Of ultimate interest is the molecular basis for motility and cell-cell and cell-substrate interactions.