Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA.
Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA.
Nat Struct Mol Biol. 2021 Feb;28(2):181-189. doi: 10.1038/s41594-020-00548-4. Epub 2021 Jan 18.
Cholesterol serves critical roles in enveloped virus fusion by modulating membrane properties. The glycoprotein (GP) of Ebola virus (EBOV) promotes fusion in the endosome, a process that requires the endosomal cholesterol transporter NPC1. However, the role of cholesterol in EBOV fusion is unclear. Here we show that cholesterol in GP-containing membranes enhances fusion and the membrane-proximal external region and transmembrane (MPER/TM) domain of GP interacts with cholesterol via several glycine residues in the GP2 TM domain, notably G660. Compared to wild-type (WT) counterparts, a G660L mutation caused a more open angle between MPER and TM domains in an MPER/TM construct, higher probability of stalling at hemifusion for GP2 proteoliposomes and lower cell entry of virus-like particles (VLPs). VLPs with depleted cholesterol show reduced cell entry, and VLPs produced under cholesterol-lowering statin conditions show less frequent entry than respective controls. We propose that cholesterol-TM interactions affect structural features of GP2, thereby facilitating fusion and cell entry.
胆固醇通过调节膜性质在包膜病毒融合中发挥关键作用。埃博拉病毒(EBOV)的糖蛋白(GP)在内涵体中促进融合,这是一个需要内涵体胆固醇转运蛋白 NPC1 的过程。然而,胆固醇在 EBOV 融合中的作用尚不清楚。在这里,我们表明含有 GP 的膜中的胆固醇增强了融合,并且 GP 的膜近端外部区域和跨膜(MPER/TM)结构域通过 GP2 TM 结构域中的几个甘氨酸残基与胆固醇相互作用,特别是 G660。与野生型(WT)相比,G660L 突变导致 MPER 和 TM 结构域之间的夹角更大,GP2 脂蛋白体在半融合时停顿的概率更高,病毒样颗粒(VLPs)进入细胞的效率更低。胆固醇耗尽的 VLPs 显示出降低的细胞进入,并且在降低胆固醇的他汀类药物条件下产生的 VLPs 比各自的对照进入的频率更低。我们提出胆固醇-TM 相互作用影响 GP2 的结构特征,从而促进融合和细胞进入。