Alternative folding of soluble proteins induced by Aβ42 and Tau in aged cells

摘要 阿尔茨海默病(AD)研究的主要目标之一是了解衰老和聚集的 β和/或过度磷酸化的Tau破坏蛋白平衡，导致神经元进行性死亡。海流 AD的研究范式主要集中在Aβ/Tau的淀粉样蛋白聚集以及由此隔离的蛋白质 集合体。蛋白质平衡的一个关键未触及的问题是可溶性蛋白质的折叠和构象， 它们占蛋白质组的99%，在衰老和阿尔茨海默病中也会发生变化。AS蛋白质构象 确定特定细胞功能的特定蛋白质(S)，蛋白质折叠和构象的变化 会破坏原有的蛋白质功能或允许某些多肽获得年龄/AD特有的功能。 新生的多肽在从头折叠过程中采取动力学和热力学上的有利路线。这个 决定蛋白质折叠路径和最终天然构象的能量格局由 新生多肽周围的物理化学环境。利用酿酒酵母(芽殖酵母) 作为一种模式生物和一种新的蛋白质组学-结构管道，我们的初步研究表明，变化 细胞折叠环境诱导许多蛋白质的选择性折叠。随着蛋白质组的变化 细胞折叠环境的两个关键成分--组成和代谢谱是保守的 作为衰老和阿尔茨海默病的标志，本提案的目的是了解衰老和阿尔茨海默病如何影响折叠和 可溶性蛋白质的构象。我们建议在这个试验项目中使用发芽酵母，因为这是一种常见的 用于研究衰老的细胞和分子机制的模式生物。酵母具有众多的生物特性 与动物的过程和发展与年龄相关的细胞功能障碍，类似于人类的衰老。此外， AD的酵母模型已被建立以揭示淀粉样蛋白聚集的保守机制和细胞 β和Tau的毒性。衰老是AD和其他与年龄相关的痴呆的主要危险因素。但是，以前的 研究着眼于表达人Aβ/Tau蛋白的年轻酵母细胞。在这个提议的项目中，我们希望 结合酵母菌老化强度和AD研究寻找Aβ42/Tau诱导的替代蛋白质折叠 在老化的细胞中。我们打算通过1)确定蛋白质替代折叠的普及率来实现我们的目标 2)分析Aβ42/Tau对衰老细胞蛋白质折叠的影响。来自我们的热门歌曲 该项目将为该领域的研究人员提供资源，以确定相关蛋白质功能的获得或丧失 通过这些蛋白质的选择性折叠。这项工作有望揭示受影响的蛋白质组的第一个3D视图 按年龄和Aβ42/Tau。

ABSTRACT One of the major goals of Alzheimer’s disease (AD) research is to understand how aging and the aggregation of Aβ and/or hyperphosphorylated Tau disrupt the proteostasis and cause progressive neuronal death. The current paradigm of AD research focuses on the amyloid aggregation of Aβ/Tau and the proteins sequestrated by these aggregates. A key untouched question of proteostasis is whether the folding and conformation of soluble proteins, which represent >99% of the proteome, are also changed during aging and AD. As protein conformation determines the specific cellular function(s) of a given protein, the changes in protein folding and conformation will disrupt the original protein functions or allow some polypeptides to acquire age-/AD-specific functions. Nascent polypeptides take kinetically and thermodynamically favorable routes during de novo folding. The energy landscape that determines the folding paths and final native conformations of a protein is shaped by the physiochemical environment surrounding the nascent peptide. Using Saccharomyces cerevisiae (budding yeast) as a model organism and a novel proteomics-structure pipeline, our preliminary studies revealed that changing the cellular folding environment induces the alternative folding of many proteins. As changes in the proteome composition and metabolic profile, two key components of the cellular folding environment, are conserved hallmarks of aging and AD, the goal of this proposal is to understand how aging and AD affect the folding and conformation of the soluble proteins. We propose to use budding yeast for this pilot project as it is a common model organism used to study cellular and molecular mechanisms of aging. Yeast shares numerous biological processes with animals and develops age-related cellular dysfunctions similar to human aging. In addition, the yeast model of AD has been developed to reveal conserved mechanisms of amyloid aggregation and the cellular toxicity of Aβ and Tau. Aging is the major risk factor of AD and other age-related dementias. However, previous studies looked at the young yeast cells expressing human Aβ/Tau proteins. In this proposed project, we want to combine the strength of aging and AD research in yeast to find alternative protein folding induced by Aβ42/Tau in aged cells. We intend to accomplish our goal by 1) determining the prevalence of protein alternative folding induced by aging, and 2) dissecting the effect of Aβ42/Tau on protein folding in aged cells. The hits from our project will be a resource for researchers in the field to determine the gain or loss of protein functions associated with these alternative folding of proteins. This work is expected to reveal the first 3D view of the proteome affected by aging and Aβ42/Tau.