Towards the understanding of how chaperones function and prevent amyloidogenic diseases

项目总结/摘要 阿尔茨海默病（AD）是一种致命的神经退行性疾病，影响550万美国人。尽管 经过几十年的研究，仍然没有已知的治疗方法。AD是一种蛋白质错误折叠疾病， 阿尔茨海默氏症蛋白Aβ从无规卷曲实体聚集成高度组织化的原纤维 含有交叉β折叠结构的聚集体。然而，阿尔茨海默氏症中有毒物质的性质 疾病仍然未知。Aβ聚集的可能性越来越受到人们的关注 线粒体内，而不是细胞外沉积的Aβ，可能是负责发病和 疾病的进展。大自然已经开发出了防止疾病相关蛋白的机制 聚集，例如通过引入热休克蛋白（Hsp's），当细胞聚集时， 承受压力。线粒体中最重要的Hsp是Hsp 60和Hsp 70，而Hsp 60是线粒体中最重要的Hsp。 细菌、酵母和哺乳动物中唯一必需的伴侣蛋白。已知Hsp 60具有细胞保护作用， 细胞中有许多应激源，并被认为是直接预防AD的。然而，我们一无所知 这是如何实现的机制。 由于对线粒体Hsp 60系统（包括其辅助分子Hsp 10）几乎一无所知， 将使用本提案的目标1和2来探索在不存在底物蛋白的情况下的这种分子伴侣。我寻求 利用冷冻电子技术解决了蛋白质折叠过程中分子伴侣的不同状态结构 显微镜（cryo-EM）。此外，使用新的溶液状态NMR方法来研究稀疏布居的 国家，我将研究如何在反应周期的共同伴侣。这将提供重要的 Hsp 10在基质包封中的作用。此外，在我的独立阶段，我将 使用通过目标1和2获得的基础知识，继续目标3，在那里我将学习 热休克蛋白60与Aβ相互作用我不仅将阐明与Aβ结合的长寿命主要状态的结构， 用冷冻电镜观察基质包封后的Hsp 60，还研究了Aβ与Hsp 60的瞬时相互作用 在包封之前，在基底折叠循环的初始阶段期间，通过溶液状态NMR。这些 研究将提供关于Aβ种类（单体、寡聚体或原纤维）与Hsp 60相互作用的信息 并阐明其结构特征。目标1和目标2将深入探讨以下基本问题： 分子伴侣用于有效折叠蛋白质使其成为功能形式的机制。进一步的结果 将揭示Hsp 60如何抑制Aβ聚集和预防神经退行性变的细节。 疾病，并可能开辟新的治疗策略，对阿尔茨海默病。

Project Summary/Abstract Alzheimer's disease (AD) is a fatal neurodegenerative disease affecting 5.5 million Americans. Despite many decades of research there is still no known cure. AD is a protein misfolding disease, where the Alzheimer's protein, Aβ, aggregates from a random coil entity into fibrils, which are highly organized aggregates containing a cross-β sheet structure. However, the nature of the toxic species in Alzheimer's disease remains unknown. More and more attention has been given to the possibility that Aβ aggregates within mitochondria, rather than extracellular deposits of Aβ, may be responsible for the onset and progression of the disease. Nature has developed mechanisms to prevent disease-associated protein aggregation, e.g. by the introduction of heat shock proteins (Hsp's), which are overexpressed when cells undergo stress. The most important Hsp's in mitochondria are Hsp60 and Hsp70, whereas Hsp60 is the only essential chaperone in bacteria, yeast, and mammals. It is known that Hsp60 is cytoprotective against many stressors in cells and is proposed to be directly protective against AD. However nothing is known about the mechanism of how this is achieved. Since almost nothing is known about the mitochondrial Hsp60 system, including its co-chaperone Hsp10, I will use aims 1 and 2 of this proposal to explore this chaperone in absence of substrate protein. I seek to solve the structure of different states of the chaperone during its protein folding cycle by cryo-electron microscopy (cryo-EM). Further, using novel solution-state NMR methods to study sparsely-populated states, I will investigate how the co-chaperone is involved in the reaction cycle. This will provide important information on the role of Hsp10 in substrate encapsulation. Further, during my independent phase I will use the fundament knowledge obtained through aims 1 and 2 to move on to aim 3, where I will study the interaction of Hsp60 with Aβ. I will not only elucidate the structure of long-lived major states of Aβ bound to Hsp60 after substrate encapsulation by cryo-EM, but also study the transient interaction of Aβ with Hsp60 during the initial phase of the substrate folding cycle, prior to encapsulation, by solution-state NMR. These studies will provide information about which Aβ species (monomer, oligomer, or fibril) interact with Hsp60 and elucidate their structural features. Aims 1 and 2 will provide insights into fundamental questions about the mechanisms chaperones use to efficiently fold proteins into their functional forms. Further the results from aim 3 will unveil details about how Hsp60 inhibits Aβ aggregation and prevents neurodegenerative diseases, and may open up novel therapeutic strategies against Alzheimer's disease.