MODULATION OF VON WILLEBRAND FACTOR BINDING FACTOR VIII

所提出的研究目标是首先，确定其影响的特征 血浆第八因子与血管性血友病因子(VWF)的结合 鉴定一种可抑制因子VIII结合的vWF结合蛋白。各方面 如第八因子相互作用的亲和力和化学计量 我们将研究纯vWF和vWF在等离子体中重组的情况。会的 还可以确定可能的血浆vWF结合蛋白 降低第VIII因子与vWF的关联率或增加 从vWF解离的速率。这些发现的重要性与 为了更好地了解血浆凝血因子VIII水平的调节 妊娠、炎症和DDAVP治疗以及次要因素 八、虚弱。到目前为止，对次要因子VIII的解释 缺陷仅限于第VIII因子与vWF的“结合减少”。 针对血管性血友病因子因子结合区的特异性突变。 理解另一种蛋白质与其他蛋白质结合的结合动力学 VWF有助于更好地表征继发性第VIII因子缺乏症。 这项提案的第二个目标是确定 影响与因子VIII相互作用的VWF。要实现这一点 目的，我们将专注于研究，以表征内部和外部的作用 因子VIII上的亚基内vWF二硫键结合。我们将进行 平衡和动力学研究将比较因子VIII的结合 多聚体vWF和不能形成多聚体的突变体vWF。在……里面 此外，我们将基于在一个 继发性因子VIII缺乏症患者(R91Q和C268S)，以及 研究vWF Cys 268在凝血因子VIII结合中的作用。VWF 调节因子的水平，这已被证明可以增加其 深静脉血栓形成(DVT)患者的血浆水平。我们的结果可能会改变 对深静脉血栓形成机制的认识。

The goals of the research proposed are first, to characterize the effect of plasma on factor VIII binding to von Willebrand factor (vWF) and identify a vWF-binding protein that inhibits factor VIII binding. Aspects such as affinity and stoichiometry for the interaction of factor VIII with pure vWF vs. vWF reconstituted in plasma will be studied. It will also be determined whether the putative plasma vWF-binding protein decreases the rate of factor VIII association with vWF or increases the rate of dissociation from vWF. The importance of these findings relates to a better understanding of modulation of factor VIII levels in pregnancy, inflammation and DDAVP therapy, as well as secondary factor VIII deficiency. Until now, the explanation of secondary factor VIII deficiency is limited to a "decreased binding" of factor VIII to vWF due to specific mutations in the factor VIII binding region of vWF. Understanding binding kinetics of the association of another protein with vWF will help to better characterize secondary factor VIII deficiency. The second goal of this proposal is to identify structural features of vWF that influence the interaction with factor VIII. To accomplish this aim, we will focus on studies to characterize the role of inter and intrasubunit vWF disulfide bonds on factor VIII binding. We will conduct equilibrium and kinetics studies that will compare binding of factor VIII to multimeric vWF and mutant vWF incapable of multimer formation. In addition, we will construct vWF mutants based on mutations found in a patient with secondary factor VIII deficiency (R9lQ and C268S), and investigate what is the role of vWF Cys 268 on factor VIII binding. vWF regulates the levels of factor VIII, which has been shown to increase its plasma levels in deep venous thrombosis (DVT). Our results may alter the understanding of pathogenesis of DVT.