Structure and Function of Alpha-Synuclein

描述（由申请人提供）：α-突触核蛋白（aS）的聚集在帕金森病（PD）的发病机制中起着重要但仍知之甚少的作用。aS的正常功能仍然未知，但该蛋白质结合到磷脂膜上，并被认为调节突触囊泡池大小、囊泡回收、神经递质运输和释放以及突触可塑性。自从发现aS和PD之间的联系以来，人们对鉴定影响蛋白质的致病或正常作用的aS相互作用伙伴产生了极大的兴趣。在过去的几年中，越来越多的蛋白质，聚合物和小分子已被报道与aS结合并改变其聚集动力学和/或其脂质相关功能。其中有两个突触核蛋白家族的其他成员，B-突触核蛋白（BS）和γ-突触核蛋白（yS）。共价修饰也影响aS聚集和功能。然而，这些各种绑定相互作用和修改影响aS行为的机制还没有很好地理解。我们已经表明，在游离的aS的残留结构可能发挥重要作用，在介导的分子间的相互作用，淀粉样纤维形成之前，这种蛋白质。我们假设，在共价修饰或伴侣相互作用后，aS发生构象变化，这是对蛋白质聚集或正常功能产生影响的基础。因此，我们建议以高分辨率表征在aS中发生的结构变化，作为其修饰及其与不同合作伙伴的相互作用的函数，最初关注（BS，yS，组蛋白，HSP 70，PLD 2，铜和其他金属和聚阳离子。我们还建议详细阐明β-BS和γ-S在其自由和脂质结合状态下的结构，以澄清为什么aS表现出与这些近亲不同的自组装行为。最后，我们计划通过协作将合理设计的突变体引入到aS毒性和功能的酵母和苍蝇模型中，来测试我们关于结构变化在aS中的作用的结论。拟议的研究重点是提高我们对PD潜在分子机制的理解，并可能为开发新的PD治疗方法提供建议。这一结果可能对理解和治疗其他淀粉样蛋白疾病，包括阿尔茨海默病和朊病毒疾病具有更广泛的意义。

DESCRIPTION (provided by applicant): Aggregation of a-synuclein (aS) plays an important but still poorly understood role in the pathogenesis of Parkinson's disease (PD). The normal function of aS remains unknown, but the protein binds to phospholipid membranes and is believed to regulate synaptic vesicle pool size, vesicle recycling, neurotransmitter transport and release, and synaptic plasticity. Since the discovery of the link between aS and PD, there has been great interest in identifying aS interaction partners that influence either the pathogenic or normal roles of the protein. In the past few years, a growing number of proteins, polymers, and small molecules have been reported to bind to aS and alter its aggregation kinetics and/or its lipid-associated functions. Among these are two other members of the synuclein family, B-synuclein (BS) and y-synuclein (yS). Covalent modifications also affect aS aggregation and function. However, the mechanisms by which these various binding interactions and modifications influence aS behavior are not well understood. We have shown that residual structure in free aS may play an important role in mediating the intermolecular interactions that precede amyloid fibril formation by this protein. We hypothesize that upon covalent modification or partner interactions, aS undergoes conformational changes that underlie the consequent effects on the aggregation or normal functions of the protein. We therefore propose to characterize, at high resolution, the structural changes that occur in aS as a function of its modifications and its interactions with different partners, with an initial focus on (BS, yS, histones, HSP70, PLD2, copper and other metals and polycations. We also propose to elucidate in detail the structure of (BS and yS in their free and lipid-bound states to clarify why aS exhibits different self-assembly behavior from these close relatives. Finally, we plan to test our conclusions regarding the role of structural changes in aS by introducing rationally designed mutants, collaboratively, into yeast and fly models of aS toxicity and function. The proposed studies are focused on improving our understanding of the molecular mechanisms underlying PD and may suggest strategies for developing new PD therapeutics. The results may have broader implications for understanding and treating other amyloid diseases, including Alzheimer's disease and the prion diseases.