Single-vesicle imaging reveals lipid-selective and stepwise membrane disruption by monomeric α-synuclein
Single-vesicle imaging reveals lipid-selective and stepwise membrane disruption by monomeric α-synuclein
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DOI：
10.1073/pnas.1914670117
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发表时间：
2020-06-23
影响因子：
11.1
通讯作者：
Hook, Fredrik
中科院分区：
文献类型：
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作者：
Hannestad, Jonas K.;Rocha, Sandra;Hook, Fredrik
神经元蛋白 α-突触核蛋白与脂质膜的相互作用在帕金森病的背景下似乎至关重要，但潜在的机制细节，包括不同脂质在致病蛋白聚集和膜破坏中的作用，仍然难以捉摸。在这里，我们使用单囊泡分辨率荧光和无标记散射显微镜来研究单体 α-突触核蛋白与由不同带负电荷的脂质组成的表面束缚囊泡的相互作用动力学。在解释表面束缚脂质囊泡散射特性结构变化的理论模型的支持下，数据表明，当蛋白质浓度低至 10 nM（类似于每个囊泡 100 个蛋白质）时，α-突触核蛋白与磷脂酰甘油囊泡结合时，会出现逐步囊泡破坏和不对称膜变形。相比之下，磷脂酰丝氨酸囊泡仅受到轻微影响。这些对 α-突触核蛋白与脂质囊泡相互作用的结构后果的见解突出了不同阴离子脂质的对比作用，这可能与正常蛋白质功能（例如突触囊泡结合）和功能障碍（例如线粒体膜相互作用）具有机制相关性。
The interaction of the neuronal protein alpha-synuclein with lipid membranes appears crucial in the context of Parkinson's disease, but the underlying mechanistic details, including the roles of different lipids in pathogenic protein aggregation and membrane disruption, remain elusive. Here, we used single-vesicle resolution fluorescence and label-free scattering microscopy to investigate the interaction kinetics of monomeric alpha-synuclein with surface-tethered vesicles composed of different negatively charged lipids. Supported by a theoretical model to account for structural changes in scattering properties of surface-tethered lipid vesicles, the data demonstrate stepwise vesicle disruption and asymmetric membrane deformation upon alpha-synuclein binding to phosphatidylglycerol vesicles at protein concentrations down to 10 nM (similar to 100 proteins per vesicle). In contrast, phosphatidylserine vesicles were only marginally affected. These insights into structural consequences of alpha-synuclein interaction with lipid vesicles highlight the contrasting roles of different anionic lipids, which may be of mechanistic relevance for both normal protein function (e.g., synaptic vesicle binding) and dysfunction (e.g., mitochondrial membrane interaction).