STRUCTURE & MOLECULAR BIOLOGY OF THE PROTEIN S GENE

S蛋白是调节止血作用的关键成分。蛋白质S 作为活化蛋白C的辅因子，C是一种负责 凝血途径中两种蛋白质成分的降解。 因此，S蛋白通过蛋白C的作用下调 血液凝结过程。缺乏功能蛋白的个体 S，无论是因为遗传还是环境获得性原因，都在 患血栓性疾病的风险更高。常见症状 与S蛋白缺乏症相关的有血栓性静脉炎、深静脉 血栓形成和肺血栓。在目前，遗传基础 S蛋白缺乏症及其与血栓形成的关系尚不清楚。 拟议研究的长期目标是了解 S蛋白缺乏与血栓形成的遗传基础。这将是 部分是通过拟议的研究完成的，旨在提供 进一步了解S基因的正常和异常蛋白以及 对S蛋白制品的功能性质进行研究。具体目标和 实现这些目标的方法包括：a)确定以下方面的差距 用聚合酶链式反应扩增S表达蛋白(PS-α)的A、C和I内含子 通过基因组Southern杂交进行扩增和验证； 利用DNA测序和Southern定位进行克隆和鉴定 遗传蛋白S缺陷者的PS-α基因；c) 定点突变和哺乳动物细胞表达研究 处理与角色(S)相关的结构/职能关系 蛋白质S的N-糖基化与脱糖基化的比较研究 血浆衍生蛋白S也将接受手术；以及d)分离和 血浆常规生化方法的表征 减少蛋白质S与C4b结合的相互作用的成分 蛋白。这些研究的结果将导致更好的 了解蛋白质S的结构和功能；并可能 最终改进患者的诊断和治疗方法 患有S蛋白缺乏症和由此导致的血栓性疾病。

Protein S is a key component for the regulation of hemostasis. Protein S serves as a cofactor for activated Protein C, an enzyme responsible for the degradation of two protein elements of the blood coagulation pathway. Consequently, Protein S through the action of Protein C down-regulates the blood clotting process. Individuals deficient in functional Protein S, either because of genetic or environmentally-acquired reasons, are at a higher risk of experiencing thrombotic disorders. Symptoms commonly associated with Protein S deficiency include thrombophlebitis, deep vein thrombosis, and pulmonary emboli. At the present time the genetic basis of Protein S deficiency and its relationship to thrombosis are unknown. The long-term objective of the proposed research is to understand the genetic basis of Protein S deficiency and thrombosis. This will be accomplished, in part, through the proposed studies, designed to provide a better understanding of the normal and abnormal Protein S genes and the functional properties of the Protein S products. Specific aims and methods for achieving these goals include: a) characterization of gaps in introns A, C and I of the expressed Protein S gene (PS-alpha), using PCR amplification and confirmation by genomic Southern hybridization; b.) cloning and characterization by DNA sequencing and Southern mapping of the PS-alpha gene from genetically Protein S deficient individuals; c) site-directed mutagenesis and mammalian cell expression studies to address structure/function relationships relating to the role(s) of N-glycosylation for Protein S. Comparative studies with deglycosylated plasma-derived Protein S will also be performed; and d) isolation and characterization with conventional biochemical methods of a plasma component that reduces the interaction between Protein S and C4b-binding protein. The results of these studies will lead to a better understanding of the structure and function of Protein S; and may eventually lead to improved methods of diagnosis and therapy for patients having Protein S deficiency and resulting thrombotic disorders.