Structural Analysis of IAPP Fibril Formation and Membrane Interaction

描述（由申请人提供）：项目概述：IAPP（胰岛淀粉样多肽）的错误折叠被认为在II型糖尿病中起重要作用，并且类似于参与其他年龄相关淀粉样疾病（包括阿尔茨海默病和帕金森病）的其他蛋白质。 然而，这种错误折叠过程的结构细节一直难以获得。 最近的工作，主要是从我的小组，表明定点自旋标记（SDSL）是一个强大的方法来研究淀粉样蛋白的结构。 在这项拟议的研究中，我们将使用SDSL来提供有关IAPP错误折叠所涉及的定义构象状态的详细结构信息，我们将尝试确定小分子抑制剂如何阻止这些结构的形成。 Specific Aim 1设计用于生成IAPP淀粉样蛋白原纤维的三维模型。 淀粉样原纤维是淀粉样疾病的病理标志，代表逐步错误折叠过程的最终产物。 如果没有对纤维结构的详细了解，就不可能理解淀粉样蛋白错误折叠的分子机制。 在具体目标2中，我们建议对？-螺旋，膜结合的IAPP，以提供我们以前的发现，这种膜相互作用可以催化IAPP的错误折叠的机制的理解。 在具体目标3中，我们建议提供IAPP的非纤维状细胞毒性寡聚体的详细结构信息。 重要的是，这些定义明确的寡聚体已在体内被鉴定，并被认为在淀粉样蛋白疾病，包括II型糖尿病中发挥重要作用。 在具体目标4中，我们将利用我们的SDSL方法，结合具体目标1-3的结构信息，研究小分子抑制剂如何与IAPP相互作用并防止错误折叠。 相关性：从特定目的1-4获得的结构和机制信息应极大地促进用于治疗II型糖尿病和其他淀粉样疾病（包括阿尔茨海默病和帕金森病）的治疗剂的开发。此外，我们的研究应该有可能设计突变体，选择性地改变错误折叠。 这些突变体将为研究体内错误折叠淀粉样蛋白的细胞靶点和毒性机制提供强有力的工具。

DESCRIPTION (provided by applicant): Project Summary: The misfolding of IAPP (islet amyloid polypeptide) is thought to play an important role in type II diabetes and is analogous to that of other proteins involved in other age-related amyloid diseases, including Alzheimer and Parkinson disease. However, structural details of this misfolding process have been difficult to obtain. Recent work, largely from my group, demonstrates that site-directed spin labeling (SDSL) is a powerful approach for investigating the structures of amyloidogenic proteins. In this proposed study, we will use SDSL to provide detailed structural information on defined conformational states involved in IAPP misfolding, and we will try to determine how small molecule inhibitors can prevent those structures from forming. Specific Aim 1 is designed to generate a three-dimensional model of IAPP amyloid fibrils. Amyloid fibrils are the pathological hallmarks of amyloid diseases and represent the end product of a stepwise misfolding process. Understanding the molecular mechanism of amyloid protein misfolding will not be possible without detailed knowledge of the fibrillar structures. In Specific Aim 2, we propose to perform structural studies on ?-helical, membrane-bound IAPP in order to provide a mechanistic understanding of our previous finding that such membrane interactions can catalyze the misfolding of IAPP. In Specific Aim 3, we propose to provide detailed structural information on non-fibrillar, cytotoxic oligomers of IAPP. Importantly, these well-defined oligomers have been identified in vivo, and are thought to play an important role in amyloid diseases, including type II diabetes. In Specific Aim 4, we will utilize our SDSL approach, combined with the structural information from Specific Aims 1-3, to study how small molecule inhibitors interact with IAPP and prevent misfolding. Relevance: The structural and mechanistic information obtained from Specific Aims 1-4 should greatly facilitate the development of therapeutic agents for the treatment of type II diabetes and other amyloid diseases, including Alzheimer and Parkinson disease. In addition, our studies should make it possible to design mutants that selectively alter misfolding. Such mutants would provide powerful tools for studying the cellular targets and mechanisms of toxicity of misfolded amyloid proteins in vivo.