Probing the roles of membrane and cholesterol on Aβ biogenesis and prion protein interactions

项目摘要 已知序列的蛋白质聚集与多种神经退行性变有关 精神错乱。淀粉样前体蛋白(APP)的家族突变，淀粉样蛋白β源于APP (β)蛋白是一种衍生蛋白，与阿尔茨海默病(AD)的早期发病有关。之后 十五年的基础研究，使用计算机模拟，在实验的指导下 确定决定Aβ体外聚集的因素，该阶段现在开始解决 与AD最相关的问题。它们产生的背景是多么的异质 膜环境、胆固醇和下游与辅因子的相互作用会影响 APP的切割，Aβ的产生，以及Aβ寡聚体和 介导其毒性效应的受体。我们独一无二地准备使用计算模型 回答这些问题，推动AD研究的关键领域取得进展。 在这一计算和理论研究提案中，通过协同实验来增强 研究合作，我们解决基本的生物物理问题 在三个具体目标中阐明了实际影响。(1)发展量化的 了解膜脂组成和结构异质性如何影响 在Genesis Aβ中对APP和对APP处理至关重要的分泌物的划分。(2) 阐明胆固醇在决定淀粉样变性程度中的关键作用 APP差异加工中的裂解。(3)在分子水平上表征 β单体与DNA结合过程中的构象转变和相互作用 寡聚体与细胞内的普鲁恩蛋白(PrPC)有关，与Aβ细胞毒性的可能机制有关。 拟议的协调研究将导致在分子水平上对 对β蛋白的生物发生及其作用至关重要的相互作用网络 AD中的致病因素。通过开发新的计算模型和 确定新的概念，预期的结果可能会改变景观的使用 不仅在AD领域，而且在膜的一般研究中的模拟和理论- 蛋白质的相互作用。！

Project Summary Aggregation of proteins of known sequence is linked to a variety of neurodegenerative disorders. Familial mutations in the Amyloid Precursor Protein (APP), from which the amyloid β (Aβ) protein is derived, have been linked with the early onset of Alzheimer's disease (AD). After fifteen years of fundamental research using computer simulations guided by experiments to identify the factors that determine in vitro aggregation of Aβ, the stage is now set to address questions of utmost relevance to AD. They arise in the context of how heterogeneous membrane environments, cholesterol, and downstream interactions with cofactors affect the cleavage of APP, the production of Aβ, and subsequent interactions of Aβ oligomers and receptors mediating their toxic effects. We are uniquely poised to use computational models to answer these questions and drive advances in critical areas of AD research. In this computational and theoretical research proposal, augmented by synergistic experimental research collaborations, we address fundamental biophysical questions with substantial practical implications articulated in three specific aims. (1) Developing a quantitative understanding of how membrane lipid composition and structural heterogeneity impacts the partitioning of APP and secretases critical to the processing of APP in the genesis Aβ. (2) Elucidating the crucial role cholesterol plays in determining the extent of amyloidogenic cleavage in the differential processing of APP. (3) Characterizing at the molecular-level the conformational transitions and interactions involved in the binding of Aβ monomer and oligomers to cellular prion protein (PrPC), implicated in a plausible mechanism of Aβ cytotoxicity. The proposed coordinated studies will lead to a fundamental molecular-level understanding of the network of interactions that are essential to the biogenesis of Aβ protein and its role as a pathogenic agent in AD. Through the development of novel computational models and identification of new concepts, the expected outcomes could change the landscape for the use of simulations and theory not only in the AD field but also in the general study of membrane- protein interactions.!