Mapping tauopathy-induced changes in subcellular proteostasis with compartment-targeted sensors

项目摘要。 蛋白质稳态的下降是细胞衰老和与年龄相关的疾病的一个决定性特征。最近的研究 表明每个细胞器中的蛋白质质量控制受到细胞器特异性挑战的影响， 与其他细胞区室中的蛋白质稳态相互关联。根据环境，这个细胞器 已经提出了相互依赖性以保持或扰乱蛋白质质量控制。但调查 由于缺乏合适的转基因报告基因来监测蛋白质， 体内多个细胞区室的质量控制。 阿尔茨海默氏病（AD）是由易聚集致病蛋白的作用所定义的，所述易聚集致病蛋白扰乱了 蛋白质稳态尽管局限于亚细胞定位，但这些致病蛋白质影响细胞的功能。 细胞内的多个细胞器和隔室。然而，细胞器间串扰在AD中的作用 大部分尚未开发。具体来说，目前尚不清楚特定细胞中的蛋白质稳态是否受到干扰 AD连锁致病蛋白对其他细胞中蛋白质质量控制的影响 隔间 在我们的初步研究中，我们已经产生了转基因隔室靶向的错误折叠倾向蛋白 这取决于实验设计，可以用作亚细胞蛋白质稳态的传感器或作为工具， 抵消蛋白质稳态。通过使用这些新的探针，我们发现，老化差异影响蛋白质稳态， 细胞核、内质网、线粒体和细胞质。在此基础上，我们现建议确定 AD致病蛋白如何影响不同亚细胞区室中的蛋白质质量控制，反之， 区室限制性蛋白质稳态紊乱如何影响AD。对于这些研究，我们将检查 微管相关蛋白tau（MAPT）突变体与AD相关疾病的发病有关 （额颞叶痴呆）。具体来说，我们建议确定tau蛋白病是否调节 不同细胞隔室中的蛋白质稳态;衰老如何与AD相关的致病性tau蛋白协同调节 亚细胞蛋白质稳态;以及是否相反，蛋白质错误折叠在不同的亚细胞区室 不同地影响tau蛋白病。总之，这些研究承诺提供基本的理解， 突变的tau蛋白交叉调节亚细胞蛋白质稳态，这可能与理解细胞器和 细胞功能紊乱。

PROJECT SUMMARY. Decline in proteostasis is a defining feature of cellular aging and of age-related diseases. Recent studies have shown that protein quality control in each organelle is impacted by organelle-specific challenges but also interconnected with proteostasis in other cell compartments. Depending on the context, this organelle interdependence has been proposed to preserve or derange protein quality control. However, the investigation of subcellular proteostasis has been limited by the lack of suitable transgenic reporters for monitoring protein quality control in multiple cell compartments in vivo. Alzheimer’s disease (AD) is defined by the action of aggregation-prone pathogenic proteins that perturb proteostasis. Despite a confined subcellular localization, these pathogenic proteins impact the function of multiple organelles and compartments across the cell. However, the role of inter-organelle crosstalk in AD remains largely unexplored. Specifically, it remains unknown whether perturbation of proteostasis in a specific cell compartment by an AD-linked pathogenic protein reverberates on protein quality control in other compartments. In our preliminary studies, we have generated transgenic compartment-targeted misfolding-prone proteins that, depending on the experimental design, can be used as sensors of subcellular proteostasis or as tools to offset proteostasis. By using these novel probes, we have found that aging differentially affects proteostasis in the nucleus, endoplasmic reticulum, mitochondria, and cytoplasm. On this basis, we now propose to determine how AD pathogenic proteins affect protein quality control in distinct subcellular compartments and, conversely, how compartment-restricted derangement of proteostasis impacts AD. For these studies, we will examine microtubule-associated protein tau (MAPT) mutants that have been linked to the onset of an AD-related condition (frontotemporal dementia) in humans. Specifically, we propose to determine whether tauopathy modulates proteostasis in distinct cell compartments; how aging synergizes with AD-related pathogenic tau in regulating subcellular proteostasis; and whether, conversely, protein misfolding in distinct subcellular compartments differentially impacts tauopathy. Altogether, these studies promise to provide fundamental understanding on how mutant tau cross-regulates subcellular proteostasis, which may be relevant for understanding how organelle and cell function are deranged in AD.