Protein misfolding and aggregation

描述(申请人提供)：在神经退行性疾病中经常观察到蛋白质聚集，包括最常见的成人运动神经元病，肌萎缩侧索硬化症(ALS)。在家族性肌萎缩侧索硬化症(FALS)中，20%的患者遗传了二聚体酶铜锌超氧化物歧化酶(SOD1)的突变，这些突变与SOD1聚集体的形成增加有关，这些聚集体导致运动神经元细胞死亡和潜在的FALS的细胞毒性。我们的目标是了解SOD1聚集的机制。实现这一目标可能是开发新的FALS疗法的关键一步，并将影响我们对60多种其他聚集相关疾病的理解。我们的中心假设是SOD1聚集是由未折叠/错误折叠单体物种的增加形成和/或伴侣介导的复性缺陷引起的。具体地说，我们假设突变(在FAL的情况下)、细胞环境和表达水平的波动会增加SOD1二聚体的解离、锌的损失和/或聚集体的形成速度。因此，我们将确定FALS突变对SOD1聚集机制的影响。我们将在快速的计算机模拟中描述单个SOD1二聚体的大尺度动力学。我们将通过使用用于研究大规模蛋白质构象动力学的新的多尺度蛋白质模型来研究突变型和野生型SOD1分子的动力学，来评估FAL相关突变对SOD1聚集的影响。我们还将在对多个SOD1分子的计算机模拟中表征多个SOD1分子的大规模齐聚动力学，并跟踪它们的齐聚作用。我们将通过研究突变型和野生型SOD1分子的动力学来评估FAL相关突变对SOD1聚集的影响。对于聚合反应序列的每一步，我们将使用尺寸排除层析、表面等离子体共振、分析超速离心、动态光散射、电子显微镜和计算来实验确定速率和平衡常数。实验研究的结果将反馈给计算研究，以验证和完善计算模型。反过来，计算建模将指导实验工作。相关性：对SOD1聚集的机械性理解将为理解该疾病和其他神经退行性疾病的起源和开发治疗方法提供一个框架。

DESCRIPTION (provided by applicant): Protein aggregation is frequently observed in neurodegenerative diseases, including the most common adult motor neuron disease, Amyotrophic Lateral Sclerosis (ALS). In familial ALS (FALS), 20% of patients inherit mutations in the dimeric enzyme Cu, Zn superoxide dismutase (SOD1) associated with increased formation of SOD1 aggregates that contribute to the cytotoxicity responsible for motor neuron cell death and underlying FALS. Our goal is to understand the mechanism of SOD1 aggregation. Accomplishing this goal may be a key step for the development of new FALS therapies, and will impact our understanding of over 60 additional aggregation-associated diseases. Our central hypothesis is that SOD1 aggregation is caused by the increased formation of unfolded/misfolded monomeric species, and/or defects in chaperone-mediated refolding. Specifically, we postulate that mutations (in case of FALS), fluctuations in cell environment and expression levels increase SOD1 dimer dissociation, loss of zinc, and/or the rate of formation of aggregates. We will therefore determine effects of FALS mutations, metals, on the mechanism of SOD1 aggregation. We will characterize the large-scale dynamics of a single SOD1 dimer in rapid computer simulations. We will assess the impact of FALS-associated mutations on SOD1 aggregation by examining the dynamics of mutant and wild type SOD1 molecules using novel multi-scale protein models for studies of large-scale protein conformational dynamics. We will also characterize the large-scale oligomerization dynamics of multiple SOD1 molecules in computer simulations of multiple SOD1 molecules and follow their oligomerization. We will assess the impact of FALS-associated mutations on SOD1 aggregation by examining the dynamics of mutant and wild type SOD1 molecules. For each step of aggregation reaction sequence we will experimentally determine rate and equilibrium constants using size exclusion chromatography, surface plasmon resonance, analytical ultracentrifugation, dynamic light scattering, electron microscopy, and computation. Results from experimental studies will be fed back to computational studies for validating and refining computational models. In turn, computational modeling will guide experimental work. RELEVANCE: Mechanistic understanding of SOD1 agggregation will provide a framework for understanding the origin and for developing treatments for this and other neurodegenerative diseases.