Acidic pH-Induced Conformations and LAMP1 Binding of the Lassa Virus Glycoprotein Spike.
Acidic pH-Induced Conformations and LAMP1 Binding of the Lassa Virus Glycoprotein Spike.
复制标题
LASSA病毒糖蛋白峰的酸性pH诱导的构象和LAMP1结合。
DOI：
10.1371/journal.ppat.1005418
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发表时间：
2016-02
期刊：
影响因子：
6.7
通讯作者：
Huiskonen JT
中科院分区：
文献类型：
--
作者：
Li S;Sun Z;Pryce R;Parsy ML;Fehling SK;Schlie K;Siebert CA;Garten W;Bowden TA;Strecker T;Huiskonen JT
拉沙病毒是一种有包膜的双节段RNA病毒，是所有旧大陆沙粒病毒中最流行和最致命的。病毒进入宿主细胞是由一个三重表面刺突复合物介导的，该复合物由两个病毒糖蛋白亚基GP 1和GP 2以及稳定的信号肽组成。其中，GP 1结合细胞受体，GP 2在胞吞作用期间催化病毒包膜和宿主细胞膜之间的融合。穗的分子结构和低pH值诱导的构象重排，融合前，仍然知之甚少。在这里，我们分析了三维超微结构的拉沙病毒使用电子冷冻断层扫描。亚断层图像平均产生了14-μ m分辨率的糖蛋白尖峰结构。刺突是三聚体的，覆盖病毒体包膜，并连接到底层基质。结构变化的尖峰，酸化后，支持依赖于结合溶酶体驻留受体LAMP 1和膜远端GP 1亚基的进一步解离的病毒进入机制。拉沙病毒是一种人畜共患的出血热病原体。由于该病毒可作为气溶胶传播，而且目前没有批准的疫苗或特定的抗病毒药物，因此它对人类健康造成重大影响，每年影响西非国家多达50万人。病毒进入受感染个体的细胞是阻止病毒的第一步。当我们试图确定病毒进入的分子机制时，有关病毒及其组分的结构信息可能非常有价值。然而，在拉沙病毒的情况下，这仍然知之甚少。在这里，我们使用高分辨率电子冷冻显微镜和断层扫描技术来成像化学灭活的拉沙病毒。计算机图像重建可以确定病毒的三维结构，并使我们能够定位蛋白质，脂质双层和RNA基因组成分。我们的分析非感染性病毒样颗粒在不同的pH值的存在下，在一个功能性的细胞受体，人的LAMP-1，揭示了特定的结构重排的表面蛋白钉，提供了一个分子水平的基本原理，这个重要阶段的宿主细胞进入。
Lassa virus is an enveloped, bi-segmented RNA virus and the most prevalent and fatal of all Old World arenaviruses. Virus entry into the host cell is mediated by a tripartite surface spike complex, which is composed of two viral glycoprotein subunits, GP1 and GP2, and the stable signal peptide. Of these, GP1 binds to cellular receptors and GP2 catalyzes fusion between the viral envelope and the host cell membrane during endocytosis. The molecular structure of the spike and conformational rearrangements induced by low pH, prior to fusion, remain poorly understood. Here, we analyzed the three-dimensional ultrastructure of Lassa virus using electron cryotomography. Sub-tomogram averaging yielded a structure of the glycoprotein spike at 14-Å resolution. The spikes are trimeric, cover the virion envelope, and connect to the underlying matrix. Structural changes to the spike, following acidification, support a viral entry mechanism dependent on binding to the lysosome-resident receptor LAMP1 and further dissociation of the membrane-distal GP1 subunits. Lassa virus is a zoonotic, hemorrhagic fever-causing pathogen. Because the virus can spread as an aerosol and there are no approved vaccines or specific antiviral drugs currently available, it poses a major impact on human health, affecting annually up to half a million people in West-African countries. Entry of the virus into the cells of the infected individual is the first step where the virus could be stopped. When we try to determine the molecular mechanism of virus entry, information on the structure of the virus and its components can be highly valuable. However, in the case of Lassa virus, this remains poorly understood. Here, we used high-resolution electron cryomicroscopy and tomography techniques to image chemically-inactivated Lassa virus. Computational image reconstruction allowed determination of the three-dimensional structure of the virus, and allowed us to localize the protein, lipid bilayer, and RNA genome components. Our analysis of non-infectious virus-like particles at different pH’s and in the presence of a functional cellular receptor, human LAMP-1, revealed specific structural rearrangements in the surface protein spike, providing a molecular-level rationale for this important stage of host cell entry.