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

项目总结。 蛋白质稳定性的下降是细胞衰老和与年龄相关的疾病的一个明显特征。最近的研究表明 表明每个细胞器中的蛋白质质量控制受到细胞器特定挑战的影响，但也 与其他细胞隔间中的蛋白质平衡相互关联。根据上下文的不同，这个细胞器 相互依赖已被提出用来维持或改变蛋白质质量控制。然而，调查显示， 由于缺乏合适的转基因记者来监测蛋白质，亚细胞蛋白稳定的研究受到了限制。 体内多个细胞室的质量控制。 阿尔茨海默病(AD)的定义是容易聚集的致病蛋白扰乱 蛋白质平衡。尽管局限于亚细胞定位，但这些致病蛋白会影响 细胞内有多个细胞器和隔室。然而，细胞器间串扰在AD中的作用 在很大程度上仍未被探索。具体地说，目前尚不清楚特定的蛋白质平衡是否存在扰动。 AD相关致病蛋白的细胞室对蛋白质质量控制的影响 车厢。 在我们的初步研究中，我们已经产生了转基因的针对间隔室的错误折叠倾向蛋白 根据实验设计，它可以被用作亚细胞蛋白平衡的传感器或作为工具 抵消蛋白抑制作用。通过使用这些新的探针，我们发现衰老对蛋白质平衡有不同的影响 细胞核、内质网、线粒体和细胞质。在此基础上，我们现在建议确定 AD致病蛋白如何影响不同亚细胞隔间的蛋白质质量控制，反之， 蛋白质平衡的间隔室限制性错乱如何影响AD。对于这些研究，我们将检查 与AD相关疾病发病相关的微管相关蛋白tau(MAPT)突变 (额颞性痴呆症)。具体地说，我们建议确定肌萎缩症是否调节 不同细胞间的蛋白稳定；衰老如何与AD相关的致病tau协同调节 亚细胞蛋白稳定；反之，蛋白质是否在不同的亚细胞隔间错误折叠 不同程度地影响直肠直肠痉挛。总而言之，这些研究有望提供关于如何 突变体tau交叉调节亚细胞蛋白平衡，这可能与理解细胞器和 阿尔茨海默病患者细胞功能紊乱。

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.