CELL MEDIATED HEMOSTASIS

凝血蛋白之间复杂的相互作用最初是由 被描述为级联。 该模型经过改进， 将凝血因子组织成复合物， 蛋白酶及其底物酶原蛋白都结合到膜上， 相关蛋白辅因子。 蛋白质之间的相互作用 复合物提供了一种水平的凝血调节。 我们建议 在血液凝固中存在至少两个其它水平的调节。 一个水平涉及凝血之间的活化蛋白质的交通 配合物 第二个层次涉及细胞的积极参与， 调节凝血所需的关键因子的量。 这项建议 检查止血中涉及的重要细胞相互作用。 血小板 和单核细胞将被用作表面，以组装三个凝血因子， 复合物：组织因子-因子VIIa（TF-VIIa）、因子VIIIa-因子IXa （Xase）和因子Va-因子Xa（IIase）。 Plasma快速本地化， 并提供主要塞子以及用于 组装纤维蛋白塞。 将检查单核细胞，因为它们是 模型TF含有细胞，并且它们也具有TF独立的机制， 活化因子X Ee假设细胞之间的相互作用 血小板和TF-承载细胞介导凝血之间的相互作用， 在这些细胞上组装的复合物。 我们认为，这一切的全部 一种促凝系统的作用大于其各部分的总和， 只研究个别部分不会导致一个适当的模型， 体内止血 因此，这项赠款的总体目标是检查 TF-VIIa、Xase和liase对分离的 血小板和单核细胞。 一个 理解这个相对简单的三个蛋白质复合物的系统 在两种不同的细胞类型上， 相互作用是重要的凝聚，努力扩大我们的 体内止血的概念和我们对血栓形成的理解， 出血

The complex interactions among blood coagulation proteins was initially described as a cascade. That model has been refined to take into account the organization of coagulation factors into complexes that consist of a protease and its substrate zymogen protein both bound to a membrane- associated protein cofactor. The interactions between proteins within the complex provide one level of regulation for coagulation. We suggest that there are at least two other levels of regulation in blood coagulation. One level involves the traffic of activated proteins between coagulation complexes. A second level involves the active participation of cells to regulate the amounts of key factors needed for coagulation. This proposal examines important cellular interactions involved in hemostasis. Platelets and monocytes will be used as surfaces to assemble three coagulation complexes: tissue factor-factor Vlla (TF-VIIa), factor VIIIa-factor IXa (Xase), and factor Va-factor Xa (llase). Platelets quickly localize at the site of an injury and provide a primary plug as well as a surface for assembling a fibrin plug. Monocytes will be examined because they are a model TF-containing cell, and they also have a TF independent mechanism for activating factor X. Ee hypothesize that cellular interactions between platelets and TF-bearing cells mediate interactions between the coagulation complexes assembled on these cells. We believe that the totality of this type of procoagulant system is more than the sum of its parts, and that a study of only the individual parts will not lead to an adequate model of in vivo hemostasis. So the overall goal of this grant is to examine the concerted and interrelated activity of TF-Vlla, Xase, and liase on isolated platelets and monocytes by kinetic analysis and immunochemical methods. An understanding of this relatively simple system of three protein complexes on two different cell types should allow us to model other cell-protein interactions that are important in coagulation in an effort to expand our concept of in vivo hemostasis and our understanding of thrombosis and hemorrhage.