PHYSIOLOGICAL MECHANISMS OF INTEGRIN AFFINITY MODULATION

描述(改编自调查人员摘要)：血细胞，如 血小板、淋巴细胞和中性粒细胞发挥其生理功能。 通过与细胞外基质或与其他 细胞。整合素是一类跨膜型α、β异源二聚体 它们介导了许多这些细胞类型的黏附，值得注意的是 他们的动态调节。作为对外界刺激的反应，整合素 上调配体结合亲和力，改变细胞粘附性。 初步数据显示整合素“激活”或亲和力 调制涉及通过整合素的细胞特异性信号传递 胞质结构域。在这项提案中，私人投资局将澄清这一点。 生理途径。首先，他将确定阿尔法和贝塔亚基 涉及的细胞质残留物。使用细胞外AlphaIIb， 作为报告基团，他将产生不同的细胞质结构域， 将这些构建物导入异种细胞，并分析它们的 结合抗体或蛋白质配体的能力。第二，他将审查 整合素胞质结构域过表达对血管内皮细胞生长的影响 生理激活机制。嵌合体由 IL-2受体的胞外区和跨膜区连接到 获得了特异的整合素胞质结构域。这些 构建的载体将与具有构成活性的整合素共转染。 并分析了其对结合的抑制作用。最后，他会尝试 确定与整合素相互作用的假想胞浆因子 胞质结构域。新的因素将被分离和鉴定 利用上述抑制嵌合体进行的交联化研究， 或者通过在双杂交系统中再生GAL4转录因子。 确定亲和力调节的机制对于 了解整合素在血管紧张素转换酶生理学和病理学中的作用 血细胞。

DESCRIPTION (Adapted from investigator's abstract): Blood cells such as platelets, lymphocytes and neutrophils exert their physiological function through adhesive interactions with the extracellular matrix or with other cells. The integrins, a family of transmembrane alpha, beta heterodimers which mediate the adhesion of many of these cell types, are notable for their dynamic regulation. In response to external stimuli, integrins upregulate ligand binding affinity and alter cellular adhesiveness. Preliminary data suggest that integrin "activation" or affinity modulation involves cell- specific signalling through integrin cytoplasmic domains. In this proposal, the PI will elucidate this physiological pathway. First, he will identify alpha and beta subunit cytoplasmic residues which are involved. Using extracellular alphaIIb, beta3 as a reporter group, he will generate variant cytoplasmic domains, transfect these constructs into heterologous cells and analyze their ability to bind antibody or protein ligands. Second, he will examine the effect of overexpression of integrin cytoplasmic domains on physiological activation mechanisms. Chimera consisting of the extracellular and transmembrane regions of the IL-2 receptor joined to specific integrin cytoplasmic domains have been obtained. These constructs will be co-transfected with constitutively active integrins and the inhibitory effect on binding analyzed. Finally, he will attempt to identify hypothetical cytosolic factors which interact with integrin cytoplasmic domains. Novel factors will be isolated and identified in crosslinking studies utilizing the inhibitory chimera identified above, or by regenerating the GAL4 transcription factor in a two hybrid system. Defining the mechanisms of affinity modulation is crucial to understanding the role of integrins in the physiology and pathology of blood cells.