MRC Laboratory for Molecular Cell Biology, University College London, London, UK.
CoMPLEX, University College London, London, UK.
Nat Microbiol. 2019 Oct;4(10):1636-1644. doi: 10.1038/s41564-019-0488-4. Epub 2019 Jul 8.
To achieve efficient binding and subsequent fusion, most enveloped viruses encode between one and five proteins. For many viruses, the clustering of fusion proteins-and their distribution on virus particles-is crucial for fusion activity. Poxviruses, the most complex mammalian viruses, dedicate 15 proteins to binding and membrane fusion. However, the spatial organization of these proteins and how this influences fusion activity is unknown. Here, we show that the membrane of vaccinia virus is organized into distinct functional domains that are critical for the efficiency of membrane fusion. Using super-resolution microscopy and single-particle analysis, we found that the fusion machinery of vaccinia virus resides exclusively in clusters at virion tips. Repression of individual components of the fusion complex disrupts fusion-machinery polarization, consistent with the reported loss of fusion activity. Furthermore, we show that displacement of functional fusion complexes from virion tips disrupts the formation of fusion pores and infection kinetics. Our results demonstrate how the protein architecture of poxviruses directly contributes to the efficiency of membrane fusion, and suggest that nanoscale organization may be an intrinsic property of these viruses to assure successful infection.
为了实现有效的结合和随后的融合，大多数包膜病毒编码一到五个蛋白质。对于许多病毒来说，融合蛋白的聚集及其在病毒粒子上的分布对融合活性至关重要。痘病毒是最复杂的哺乳动物病毒，专门为结合和膜融合分配了 15 种蛋白质。然而，这些蛋白质的空间组织以及它们如何影响融合活性尚不清楚。在这里，我们表明，痘病毒的膜被组织成不同的功能域，这些功能域对于膜融合的效率至关重要。我们使用超分辨率显微镜和单颗粒分析发现，痘病毒的融合机制仅存在于病毒粒子尖端的簇中。融合复合物的单个成分的抑制破坏了融合机制的极化，这与报道的融合活性丧失一致。此外，我们还表明，从病毒粒子尖端置换功能融合复合物会破坏融合孔的形成和感染动力学。我们的结果表明，痘病毒的蛋白质结构如何直接有助于膜融合的效率，并表明纳米级组织可能是这些病毒确保成功感染的固有特性。
