STRUCTURE AND FUNCTION OF THE INTEGRIN ALPHA 1 BETA 1

我们的研究集中在整合素的结构和功能上，整合素的结构和功能 是许多细胞外的跨膜异二聚体受体 基质分子。这些受体由α和β亚基组成。 最初，我们使用人整合素α1beta1作为模型系统 为了回答关于结构-功能关系的主要问题， 阿尔法域和贝塔域。我们最近发现，细胞质中的 这些受体的结构域可能控制着细胞内的整合素 功能。这项提议的目标是确定两国关系 整合素受体的结构与其功能之间的关系。我们有 在这个项目中有两个主要的广泛目标。首先，我们将描述 整合素中发生配基后结合事件的机制，以及 分离调节这些事件的基因。第二，我们将确定配基 结合结构域，然后分离参与调控的基因 配体结合的亲和力。我们最近的结构-功能实验已经 研究表明，α细胞质结构域在细胞周期中起着调节作用 整合素β细胞质功能的调节。它通过以下方式实现这一点 这两个领域之间的联系，我们正在逐一研究- 两个结构域的定向突变。我们将使用一个强有力的支配者 负性结构作为鉴定β细胞质的探针 结构域结合蛋白，通过一种策略，涉及拯救 显性负性表型。我们识别配基结合的实验 Alpha1中的主题仍在继续，我们将确定 IV型胶原蛋白结合。最后，我们将研究整合素的激活。 血小板整合素IIb/IIIa，然后在CHO细胞中表达。 使用一种新开发的渗透方案，我们将能够 确定由内向外激活所需的物质。这些实验 将帮助我们了解粘附力的调节，这是 动脉粥样硬化中的迁移。此外，这些实验也将有助于 我们对整合素自内而外激活机制的理解 信号传递，这在迁移和血小板黏附中是关键的。

Our research is focused on the structure and function of integrins, which are transmembrane heterodimeric receptors for a number of extracellular matrix molecules. These receptors are composed of alpha and beta subunits. Initially, we have used the human integrin alpha1beta1 as a model system in order to answer major questions of the structure-function relationships in alpha and beta domains. We have recently shown that both cytoplasmic domains of these receptors may be controlling integrin intracellular function. The goal of this proposal is to determine the relationship between the structure of integrin receptors and their functions. We have two primary broad goals in this project. One, we will characterize the mechanism by which post-ligand binding events in integrins occur, and isolate genes which mediate those events. Two, we will identify ligand binding domains, and then isolate genes involved in the modulation of the affinity of ligand binding. Our recent structure-function experiments have shown that the alpha cytoplasmic domain plays a regulatory role in the modulation of integrin beta cytoplasmic function. It accomplishes this via an association between these two domains, which we are studying by site- directed mutagenesis of both domains. We will use a potent dominant negative construct as a probe for the identification of beta cytoplasmic domain binding proteins, through a strategy which involves rescue of the dominant negative phenotype. Our experiments identifying ligand binding motifs within alpha1 continue, and we will pinpoint regions necessary for collagen IV binding. Lastly, we will study activation of integrins using the platelet integrin IIb/IIIa, which is then expressed in CHO cells. Using a newly developed permeabilization scheme, we will be able to identify substances required for inside out activation. These experiments will help us understand regulation of adhesion, which is central to migration in atherosclerosis. Furthermore, these experiments will also aid our understanding of the mechanism of integrin activation via inside-out signalling, which is critical in migration and in platelet adhesion.