Structures and biological activity of alpha-synuclein aggregation

摘要 联核病是一组与折叠错误有关的神经退行性疾病 大脑中的淀粉样蛋白α-突触核蛋白。错误折叠的α-突触核蛋白可以聚集成多态的纤维， 表现出不同的生物学活动，对疾病有不同的贡献。然而，潜在的 机制仍不清楚。为了解决这一问题，我们将整合结构性和功能性方法，以 研究重组野生型、疾病相关突变体和脑源性α-突触核蛋白纤维。首先，我们将使用 低温电子显微镜(Cryo-EM)，与其他结构方法相结合，实现近原子 野生型和疾病突变体α-突变体的重组全长纤维的结构(目标1-2)。我们会 然后超越结构测定，利用种子和毒性的细胞测试来探索 野生型和疾病突变型α-突变体的生物学活性。通过比较两种结构的 这些原纤维，我们将确定负责其生物活性的结构元素，并将其关联 对种子和毒性的结构差异以更好地了解它们的构效关系 (目标2)。最后，我们将确定来自患者的体内α-突触核蛋白纤维的冷冻-EM结构 联体核病的大脑。因此，我们可以评估所确定的重组人的病理相关性 α-突触核蛋白原纤维中观察到的纤维结构及其与不同疾病状态相关的结构特征(目标3)。 不同形态α-突触核蛋白原纤维的整合方法、连接结构和生物活性 来源，将揭示原子对潜在机制的理解并提供治疗靶点 适用于未来的药物开发，精确地针对α-突触核蛋白聚集来阻止突触核病。

Summary Synucleinopathies are a group of neurodegenerative disorders that have been associated to the misfolded amyloid protein α-synuclein in brain. The misfolded α-synuclein can aggregate into polymorphic fibrils, displaying distinct biological activities and contributing differently to the diseases. However, the underlying mechanisms remain unclear. To address this, we will integrate both structural and functional approaches to study recombinant wild type, disease-related mutants, and brain-derived α-synuclein fibrils. First, we will use cryo-Electron Microscopy (cryo-EM), combined with other structural methods, to achieve near-atomic structures of recombinant full-length fibrils of wild type and disease mutant α-synuclein (Aims 1-2). We will then go beyond structure determination and utilize cellular assays of seeding and toxicity to explore the biological activities of both wild type and disease mutant α-synuclein fibrils. By comparing the structures of these fibrils, we will determine structure elements responsible for their biological activity, and correlate structural differences to seeding and toxicity for a better understanding of their structure-activity relationship (Aim 2). Finally, we will determine cryo-EM structures of in vivo α-synuclein fibrils derived from the patient brains of synucleinopathies. Thus we can assess the pathological relevance of the determined recombinant fibril structures and relate structural features observed in α-synuclein fibrils to different disease states (Aim 3). Our integrated approach, connecting structure and biological activity of α-synuclein fibrils of different forms or sources, will reveal atomic understanding of the underlying mechanisms and provide therapeutic targets suitable for future drug development that precisely targets α-synuclein aggregation to stop synucleinopathies.