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

项目摘要 已知序列的蛋白质的聚集与多种神经退行性疾病有关。 紊乱淀粉样前体蛋白（APP）的家族性突变， （Aβ）蛋白是其衍生物，已被认为与阿尔茨海默病（AD）的早期发病有关。后 十五年的基础研究，使用计算机模拟实验指导， 确定决定Aβ体外聚集的因素，现阶段将解决 与AD最相关的问题。它们是在这样一个背景下产生的： 膜环境、胆固醇和下游与辅因子的相互作用影响着细胞的生长。 APP的裂解，Aβ的产生，以及随后Aβ寡聚体和 受体介导其毒性作用。我们正准备利用计算模型 回答这些问题并推动AD研究关键领域的进步。 在这个计算和理论研究的建议，增强协同实验 研究合作，我们解决基本的生物物理问题， 三个具体目标中阐述的实际影响。(1)开发定量 了解膜脂组成和结构异质性如何影响 在Aβ发生中APP和对APP加工至关重要的分泌酶的分配。（二） 阐明胆固醇在决定淀粉样蛋白生成程度中的关键作用 （3）在分子水平上表征了APP差异加工过程中的裂解过程， 参与Aβ单体结合的构象转变和相互作用， 与细胞朊病毒蛋白（PrPC）的寡聚体，涉及Aβ细胞毒性的合理机制。 拟议的协调研究将导致对以下问题的基本分子水平的理解： Aβ蛋白的生物发生所必需的相互作用网络及其作为一种蛋白质的作用。 AD的病原体。通过开发新的计算模型， 新概念的确定，预期成果可能会改变使用的景观 不仅在AD领域，而且在膜的一般研究中， 蛋白质相互作用

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.!