Initiation and Regulation of Blood Coagulation

凝血级联反应是通过凝血因子VII（a）（FVIIa）与 其细胞表面受体，组织因子（TF）。TF的异常表达是其主要原因 用于与各种疾病相关的血栓性疾病。TF表达的适当调节是 对于维持止血平衡和一般健康至关重要。的广泛和 本提案的长期目标是了解控制 TF依赖性凝血的启动和调节。大部分TF位于细胞表面 存在于一个神秘的（凝血剂不活跃）状态。多种细胞变化可以改变 但目前还不清楚，甚至如何凝血活性TF 不同于TF的加密形式或解密所涉及的机制。研究 目标1中提出的方法将研究已经提出来解释的冲突机制， TF解密并获得新的数据，以便更好地了解该过程 TF激活。除了TF加密外，TF的内吞和胞吐也可以起到一定的作用。 在调节TF活性的细胞表面的作用，但很少有人知道的分子 管制TF贩运的程序。目标2中描述的研究将确定和描述 这是负责TF内吞和运输的机制。因此， 建议的研究是（1）描绘TF激活的分子基础，特别是在 参考硫醇氧化和磷脂在外膜的变化，和（2）定义 调节TF内吞和运输的机制。拟议的研究将采用 各种生物化学、分子和细胞生物学技术，包括最先进的共聚焦显微镜， 显微镜从拟议的研究中获得的数据将提供新的见解， 了解TF活性如何在细胞表面调节，并将解决最近的 关于TF激活的争议。总体而言，从拟议研究中获得的知识将 有助于理解血栓性疾病的发病机制， 出血性和血栓性疾病的更好治疗策略 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.