Protein Z Dependent Proteinase Inhibitor

描述(申请人提供)：蛋白Z(PZ)是一种依赖维生素K的血浆蛋白，其功能此前尚不清楚。我们的工作表明，PZ是一种辅因子，可以增强(1000倍)凝血因子Xa结合在磷脂表面的抑制作用，这种凝血因子Xa是一种以前未知的血浆蛋白，称为PZ依赖的蛋白酶抑制物(ZPI)。ZPI是SERPIN超家族中的一员，它不仅以PZ、钙和磷脂依赖的方式抑制凝血因子Xa，而且还直接抑制凝血因子Xa。这项建议的目的是通过使用人类临床材料(目标B)和小鼠模型(目标C)，仔细描述PZ和ZPI作用的生化机制(目标A)，并评估PZ和ZPI产生的凝血调节的生理学相关性。目标A下的实验将：1)确定ZPI抑制Xa因子和Xia因子的动力学；2)表征Xa、PZ和ZPI在磷脂表面的相互作用；3)表征PZ和ZPI之间的相互作用；4)确定PZ的伽马-羧基谷氨酸结构域中的结构和ZPI中可能影响这些功能特性的氨基末端延伸。在目标B中，将在不同的人群/患者组中测量PZ和ZPI，以确定年龄、性别、种族背景和激素治疗对其血浆水平的影响，并评估它们与血栓性疾病的潜在关系。在目标C中，PZ和ZPI基因缺失的小鼠和人类疾病的小鼠模型将被用来探索这些蛋白质的生理重要性。

DESCRIPTION (provided by applicant): Protein Z (PZ) is a vitamin K-dependent plasma protein whose function was previously unknown. Our work has shown that PZ serves as a cofactor to enhance (1000-fold) the inhibition of coagulation factor Xa bound at a phospholipid surface by a previously unidentified plasma protein called PZ-dependent protease inhibitor (ZPI). ZPI is a member of the SERPIN superfamily of protease inhibitors and not only inhibits factor Xa in a PZ-, Ca2+- and phospholipid-dependent manner, but also directly inhibits coagulation factor XIa. The aims of this proposal are to carefully characterize the biochemical mechanisms responsible for the actions of PZ and ZPI (Aim A) and to assess the physiologic relevance of the regulation of coagulation produced by PZ and ZPI through the use of human clinical materials (Aim B) and mouse models (Aim C). Experiments under Aim A will: 1) Define the kinetics of factor Xa and factor XIa inhibition by ZPI; 2) Characterize the interactions between factor Xa, PZ and ZPI at phospholipid surfaces; 3) Characterize the interaction between PZ and ZPI; and 4) Determine the structures within the gamma-carboxyglutamic acid domain of PZ and the amino-terminal extension in ZPI that may effect these functional properties. In Aim B, PZ and ZPI will be measured in a variety of populations/patient groups to determine the effect of age, gender, ethnic background, and hormonal therapy on their plasma levels and to evaluate their potential relationship to thrombotic disease. In Aim C, PZ and ZPI gene-deleted mice and mouse models of human disease will be used to explore the physiologic importance of these proteins.