A cationic, C-terminal patch and structural rearrangements in Ebola virus matrix VP40 protein control its interactions with phosphatidylserine
A cationic, C-terminal patch and structural rearrangements in Ebola virus matrix VP40 protein control its interactions with phosphatidylserine
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DOI：
10.1074/jbc.m117.816280
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发表时间：
2018-03-02
影响因子：
4.8
通讯作者：
Stahelin, Robert V.
中科院分区：
文献类型：
--
作者：
Del Vecchio, Kathryn;Frick, Cary T.;Stahelin, Robert V.
埃博拉病毒（EBOV）是一种丝状脂质包膜病毒，可引起出血热，死亡率高。病毒蛋白40 （VP40）是EBOV的主要基质蛋白，调控病毒从质膜出芽。VP40是一种变压器/ morphein，它可以在结构上将其天然的同型二聚体重新排列成促进病毒出芽的六聚体丝或调节病毒转录的rna结合八聚体环。VP40与磷脂酰丝氨酸（PS）等质膜脂结合，这种结合对宿主细胞出芽至关重要。然而，不同的VP40结构如何与PS相互作用，哪些必要残基参与这种关联，以及VP40是否在不同的甘油磷脂头基中对PS具有真正的选择性，这些都知之甚少。在这项研究中，我们使用脂质结合实验、MD模拟和细胞成像来研究VP40- ps相互作用的分子基础，并确定不同的VP40结构（即单体、二聚体和八聚体）是否可以与含有ps的膜相互作用。定量分析结果表明，VP40通过c端结构域的阳离子贴片（Lys（224, 225）和Lys(274, 275)）与PS囊泡结合。用丙氨酸取代这些残基使ps -囊泡结合减少了40倍，并取消了VP40在质膜上的定位。二聚体VP40对含ps膜的亲和力比单体高2倍，而VP40的八聚环的结合降低了近10倍。综上所述，这些结果表明，已知在病毒生命周期中形成的不同VP40结构对含有ps的膜具有不同的亲和力。
Ebola virus (EBOV) is a filamentous lipid-enveloped virus that causes hemorrhagic fever with a high fatality rate. Viral protein 40 (VP40) is the major EBOV matrix protein and regulates viral budding from the plasma membrane. VP40 is a transformer/morpheein that can structurally rearrange its native homodimer into either a hexameric filament that facilitates viral budding or an RNA-binding octameric ring that regulates viral transcription. VP40 associates with plasma-membrane lipids such as phosphatidylserine (PS), and this association is critical to budding from the host cell. However, it is poorly understood how different VP40 structures interact with PS, what essential residues are involved in this association, and whether VP40 has true selectivity for PS among different glycerophospholipid head-groups. In this study, we used lipid-binding assays, MD simulations, and cellular imaging to investigate the molecular basis of VP40-PS interactions and to determine whether different VP40 structures (i.e. monomer, dimer, and octamer) can interact with PS-containing membranes. Results from quantitative analysis indicated that VP40 associates with PS vesicles via a cationic patch in the C-terminal domain (Lys(224, 225) and Lys(274, 275)). Substitutions of these residues with alanine reduced PS-vesicle binding by >40-fold and abrogated VP40 localization to the plasma membrane. Dimeric VP40 had 2-fold greater affinity for PS-containing membranes than the monomer, whereas binding of the VP40 octameric ring was reduced by nearly 10-fold. Taken together, these results suggest the different VP40 structures known to form in the viral life cycle harbor different affinities for PS-containing membranes.