Role of DAF in the Complement Cascade

DAF 在补体级联中的作用

• 批准号: 7051957
• 负责人: MELVIN EDWARD MEDOF
• 金额: $ 42.58万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-09-30 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7051957
• 关键词: autoimmune disorder; complement pathway; complement pathway regulation; decay accelerating factor; experimental allergic encephalomyelitis; gene expression; gene mutation; genetic transcription; genetically modified animals; laboratory mouse; pathologic process; protein structure function; recombinant proteins; tissue /cell culture

DESCRIPTION (provided by applicant): Decay accelerating factor (DAF) is a 70 kDa intrinsic membrane regulator that protects self cells from autologous complement-mediated injury. It functions by decaying the C3 central convertases (C4b2a and C3bBb), a process which determines whether complement activation aborts or proceeds. Through previous mutagenesis studies and NMR structural analyses, we have provisionally mapped DAF's active site(s). In other work, we have prepared Daf knockout mice and have begun to characterize DAF's physiological importance in different autoimmune/inflammatory states. Our proposed research is designed to provide insights into several unresolved questions concerning DAF's function. Aim 1 focuses on precisely characterizing DAF's interface with the C3 convertases and defining its molecular mechanism of action. This should provide a basis not only for understanding DAF's function but for unraveling the actions of other C3 convertase regulators. Aim 2 focuses on further clarifying DAF's overall physiological function in vivo. This should shed important insights into the pathogeneses of a number of disorders as well as new information on immune regulation and immune effector function. Aim 3 focuses on a) characterizing the transcriptional mechanisms controlling expression levels of DAF and other intrinsic regulators and b) targeting exogenous recombinant DAF derivatives to specific sites in vivo. This latter work is relevant not only to autoimmune/inflammatory disorders but potentially also to neoplasia. New findings concerning pharmacological manipulation of the proteins' expression levels via transcriptional mechanisms could open the way to new approaches to therapy.

描述（由申请人提供）：衰变加速因子（DAF）是一种 70 kDa 的内在膜调节剂，可保护自身细胞免受自体补体介导的损伤。它通过衰减 C3 中央转化酶（C4b2a 和 C3bBb）发挥作用，这一过程决定补体激活是否中止或继续。通过之前的诱变研究和核磁共振结构分析，我们已经初步绘制了 DAF 的活性位点图谱。在其他工作中，我们制备了 Daf 基因敲除小鼠，并开始表征 DAF 在不同自身免疫/炎症状态下的生理重要性。 我们提出的研究旨在深入了解有关 DAF 功能的几个未解决的问题。目标 1 侧重于精确表征 DAF 与 C3 转化酶的界面并定义其作用分子机制。这不仅为理解 DAF 的功能，而且为阐明其他 C3 转化酶调节剂的作用提供了基础。目标2侧重于进一步阐明DAF在体内的整体生理功能。这将为许多疾病的发病机制提供重要的见解，并提供有关免疫调节和免疫效应器功能的新信息。目标 3 侧重于 a) 表征控制 DAF 和其他内在调节因子表达水平的转录机制，以及 b) 将外源重组 DAF 衍生物靶向体内特定位点。后一项工作不仅与自身免疫/炎症性疾病相关，而且还可能与肿瘤相关。关于通过转录机制对蛋白质表达水平进行药理学操作的新发现可能为新的治疗方法开辟道路。