Initiation and Regulation of Blood Coagulation

凝血级联是通过凝血因子VII(A)(FVIIa)与 其细胞表面受体组织因子(Tf)。Tf的异常表达是主要原因 用于与各种疾病相关的血栓性疾病。对转铁蛋白表达的适当调节是 对维持止血平衡和总体健康至关重要。博大精深 本提案的长期目标是了解控制 依赖于转铁蛋白的凝血的启动和调节。细胞表面的大部分转铁蛋白 以一种隐秘(凝固剂不活跃)状态存在。各种细胞变化可能会改变 隐形转铁蛋白能凝聚活性转铁蛋白，但目前甚至还不清楚凝固剂活性转铁蛋白是如何发挥作用的 与解密TF所涉及的加密形式或机制不同。这些研究 目标1中提出的将审查已提议解释的相互冲突的机制 TF解密并获得新数据，以便更好地了解该过程 转铁蛋白的激活。除了转铁蛋白的加密外，转铁蛋白的内吞和胞吐也可以发挥作用 在调节细胞表面转铁蛋白活性中的作用，但对其分子知之甚少 管制贩毒活动的程序。目标2中描述的研究将确定和描述 负责转铁蛋白内吞和运输的机制。因此，它的具体目标是 建议的研究是：(1)描述转铁蛋白激活的分子基础，特别是在 参照外膜上的硫醇氧化和磷脂变化，以及(2)定义 调节转铁蛋白内吞和转运的机制。拟议的研究将采用 各种生化、分子和细胞生物学技术，包括最先进的共聚焦技术 显微镜。从拟议研究中获得的数据将提供新的见解 了解TF活性是如何在细胞表面调节的，并将解决最近的 关于转铁蛋白激活的争论。总体而言，从拟议研究中获得的知识将是 有助于理解血栓性疾病的发病机制，并有助于设计 更好地治疗出血性和血栓性疾病 3.

The coagulation cascade is initiated by binding of the coagulation factor VII(a) (FVIIa) to its cell surface receptor, tissue factor (TF). An aberrant expression of TF is the primary reason for thrombotic disorders associated with various diseases. Proper regulation of TF expression is critical for the maintenance of hemostatic balance and for health in general. The broad and long-term objective of the present proposal is to understand the mechanisms controlling the initiation and regulation of TF-dependent blood coagulation. The majority of TF on cell surfaces exists in a cryptic (coagulant inactive) state. A variety of cellular alterations could transform cryptic TF to coagulant active TF but at present it is unclear even how the coagulant active TF differs from the cryptic form or the mechanics involved in de-encryption of TF. The studies proposed in Aim 1 will examine the conflicting mechanisms that have been proposed to explain TF de-encryption and obtain new data that would provide a better understanding of the process of TF activation. In addition to TF encryption, TF endocytosis and exocytosis could also play a role in the regulation of TF activity at the cell surface but little is known about the molecular processes that regulate TF trafficking. Studies described in Aim 2 will identify and delineate mechanisms that are responsible for TF endocytosis and trafficking. Thus, the specific aims of the proposed studies are (1) delineate the molecular basis for TF activation, particularly in reference to thiol oxidation and phospholipid changes at the outer membrane, and (2) define mechanisms that regulate TF endocytosis and trafficking. The proposed studies will employ a variety of biochemical, molecular and cell biology techniques, including state-of-the art confocal microscopy. Data obtained from the proposed studies will provide new insights towards understanding how TF activity is regulated at cell surfaces and will resolve the recent controversy on TF activation. Overall, the knowledge gained from the proposed studies will be helpful in understanding the pathogenesis of thrombotic disorders and useful for designing better treatment strategies for both hemorrhagic and thrombotic disease 3.