CYTOSKELTON-MEMBRANE INTERACTIONS

对形态发生，伤口愈合， 而病毒的转化取决于对基本原理的理解， 细胞过程如运动性，细胞形状的维持和改变， 以及细胞-细胞和细胞-基质附着。 在我们无知的核心 是缺乏对这些基本生命过程的分子 细胞骨架和细胞之间跨膜相互作用的细节 面 细胞黏菌的变形虫阶段， 盘状体易于大量生长，具有运动性， 细胞-细胞以及细胞-基质附着。 利用D.盘状突作为 一般的细胞模型，我正在研究 这种细胞的质膜和细胞质的细胞骨架蛋白。 在 在过去的三年里，我们已经分离出了细胞与细胞之间的接触区域， 聚集型无定形砂，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关联。 我们 发现整合蛋白介导血浆的特异性、可饱和结合 细胞膜的两侧肌动蛋白丝和质膜可以 在膜表面催化肌动蛋白的聚合，甚至在肌动蛋白 浓度远低于正常临界浓度， 聚合法 使用去污剂溶解和F-肌动蛋白亲和力 层析，我们已经确定了一个完整的肌动蛋白结合蛋白， 表观分子量为17，000道尔顿。 近期目标是 表征和重组17 kd蛋白，使用化学 交联以鉴定遗漏的洗涤剂敏感性肌动蛋白结合蛋白 通过F-肌动蛋白亲和层析，制备单特异性抗体 抵靠阿米巴膜的主要整体膜部件 细胞骨架，探讨跨膜的结构和调控 该系统中的链接，并确定结构是否相似 在其他物种中也发现了这种联系。 最重要的是 运动性和细胞-细胞和细胞-基质相互作用的基础。

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.