Investigating the impact of p97 mutation in Amyotrophic Lateral Sclerosis

蛋白质稳态下降是肌萎缩侧索硬化症发展的重要因素 (ALS)和其他神经退行性疾病。随着人口老龄化的不断扩大， 这些毁灭性的疾病将在未来几十年给卫生保健带来巨大负担。 p97 AAA-ATP酶是一种泛素选择性解折叠酶，在蛋白质质量控制中起关键作用。 专门的衔接蛋白将p97靶向泛素化底物，从而赋予这种丰富的 酵素p97的突变导致家族性ALS，并据报道阻碍了p97与某些衔接子的关联 并损害ER和线粒体相关的质量控制，表明对这些细胞器的靶向不足。 然而，尚未研究p97突变对其相互作用组和遍在化底物的影响 系统地在疾病中受影响的细胞类型中，即运动神经元和骨骼肌。 在此，我们将建立一个基于诱导多能干细胞（iPSC）的运动神经元疾病模型， 不同的p97突变。我们将利用这个系统：（1）研究突变型p97如何重塑运动神经元 骨骼肌蛋白质组和生理学。p97的泛素化底物将使用定量方法鉴定。 每种细胞类型的蛋白质组学(2)检查p97突变对已知蛋白质质量控制途径的影响 在运动神经元骨骼肌细胞中。 我们的研究将提供第一个由p97突变引起的ALS模型，并将提供机制的见解 p97突变如何导致运动神经元和/或骨骼肌死亡。我们预期我们的细胞模型 未来可能用于小分子筛选，以识别用于治疗开发的先导分子。给定 p97突变流行率，我们预期这些研究将与其他研究有广泛的相关性， 神经退行性疾病

Protein homeostasis decline is a significant contributor to the development of Amyotrophic Lateral Sclerosis (ALS) and other neurodegenerative disorders. With an ever-expanding aging population and no reliable therapies, these devastating diseases will place a significant burden on health care in the coming decades. The p97 AAA-ATPase is a ubiquitin-selective unfoldase that has critical roles in protein quality control. Dedicated adaptor proteins target p97 to ubiquitylated substrates and thereby impart specificity to this abundant enzyme. Mutations in p97 cause familial ALS and are reported to impede p97 association with certain adaptors and impair ER and mitochondria associated quality control suggesting inadequate targeting to these organelles. However, the impact of p97 mutation on its interactome and ubiquitylated substrates has not been studied systematically in cell types impacted in disease, namely motor neurons and skeletal muscle. Here, we will establish an induced pluripotent stem cell (iPSC)-based model of motor neuron disease caused by distinct p97 mutations. We will use this system to: (1) Investigate how mutant p97 remodels the motor neuron and skeletal muscle proteome and physiology. Ubiquitylated substrates of p97 will be identified using quantitative proteomics in each cell type. (2) Examine the impact of p97 mutation on known protein quality control pathways in motor neurons skeletal muscle cells. Our studies will provide the first model of ALS caused by p97 mutation and will provide mechanistic insight into how p97 mutation causes motor neuron and/or skeletal muscle demise. We anticipate our cell-based model may be used in the future for small molecule screens to identify lead molecules for therapy development. Given the prevalence of p97 mutation, we anticipate these studies will have broad relevance to other in neurodegenerative diseases.