The fusion peptide of semliki forest virus associates with sterol-rich membrane domains
The fusion peptide of semliki forest virus associates with sterol-rich membrane domains
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DOI：
10.1128/jvi.76.7.3267-3275.2002
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发表时间：
2002-04-01
影响因子：
5.4
通讯作者：
Kielian, M
中科院分区：
文献类型：
--
作者：
Ahn, A;Gibbons, DL;Kielian, M
塞姆利基森林病毒（SFV）是一种包膜甲病毒，其膜融合由低pH触发，并由靶膜中的胆固醇和鞘脂促进。融合由E1介导，E1是一种含有推定融合肽的病毒膜蛋白。病毒突变体研究表明，SFV的胆固醇依赖性是由融合肽外的E1区域控制的。E1和E1*（E1的可溶性胞外域形式）在依赖于低pH、胆固醇和鞘脂的反应中与膜相互作用，并形成高度稳定的同源三聚体。在这里，我们已经使用洗涤剂提取和梯度浮选实验证明，E1* 选择性地与耐洗涤剂的膜域（DRM或筏）。相反，重组全长E1蛋白或流感病毒融合肽与DRM无关。甲基β-环糊精定量提取胆固醇和E1* 从膜在没有洗涤剂，这表明一个强大的协会E1* 与甾醇。单克隆抗体的研究表明，筏协会介导的建议E1融合肽。因此，尽管E1的其他区域涉及病毒胆固醇依赖性的控制，但一旦SFV融合肽插入靶膜中，它对富含胆固醇和鞘脂的膜结构域具有高亲和力。
Semliki Forest virus (SFV) is an enveloped alphavirus whose membrane fusion is triggered by low pH and promoted by cholesterol and sphingolipid in the target membrane. Fusion is mediated by E1, a viral membrane protein containing the putative fusion peptide. Virus mutant studies indicate that SFV's cholesterol dependence is controlled by regions of E1 outside of the fusion peptide. Both E1 and E1*, a soluble ectodomain form of E1, interact with membranes in a reaction dependent on low pH, cholesterol, and sphingolipid and form highly stable homotrimers. Here we have used detergent extraction and gradient floatation experiments to demonstrate that E1* associated selectively with detergent-resistant membrane domains (DRMs or rafts). In contrast, reconstituted full-length E1 protein or influenza virus fusion peptide was not associated with DRMs. Methyl beta-cyclodextrin quantitatively extracted both cholesterol and E1* from membranes in the absence of detergent, suggesting a strong association of E1* with sterol. Monoclonal antibody studies demonstrated that raft association was mediated by the proposed E1 fusion peptide. Thus, although other regions of E1 are implicated in the control of virus cholesterol dependence, once the SFV fusion peptide inserts in the target membrane it has a high affinity for membrane domains enriched in cholesterol and sphingolipid.