Lipid raft-dependent targeting of the influenza A virus nucleoprotein to the apical plasma membrane
Lipid raft-dependent targeting of the influenza A virus nucleoprotein to the apical plasma membrane
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DOI：
10.1111/j.1600-0854.2004.00237.x
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发表时间：
2004-12-01
期刊：
影响因子：
4.5
通讯作者：
Digard, P
中科院分区：
文献类型：
--
作者：
Carrasco, M;Amorim, MJ;Digard, P
流感病毒通过从上皮细胞的顶端表面出芽获得含有脂筏的包膜。极化出芽涉及病毒膜蛋白的特异性分选，但对内部病毒体组分的运输知之甚少。我们发现，在病毒感染的后期阶段，流感核蛋白（NP）和聚合酶（基因组核糖核蛋白的蛋白质成分）定位于顶端，但不是侧膜或基底膜，即使在细胞类型的血凝素被发现在所有的外部膜。病毒粒子的其他胞质组分分布在整个细胞质中（NEP/NS 2），或者在所有细胞类型中并不仅局限于顶端质膜（M1）。NP即使单独表达也特异性地定位于顶端表面，表明内在靶向。相似比例的NP与来自病毒感染和质粒转染细胞的浮选测定中的膜组分相关。在4 degreesC耐洗涤剂浮选表明，这些膜脂筏微域。说明这一点，胆固醇消耗呈现NP洗涤剂可溶性，而且，导致其在整个细胞中的部分重新分布。我们得出结论，NP是独立的有针对性的顶端质膜通过涉及脂筏的机制，并提出这有助于确定流感病毒出芽的极性。
Influenza virus acquires a lipid raft-containing envelope by budding from the apical surface of epithelial cells. Polarised budding involves specific sorting of the viral membrane proteins, but little is known about trafficking of the internal virion components. We show that during the later stages of virus infection, influenza nucleoprotein (NP) and polymerase (the protein components of genomic ribonucleoproteins) localised to apical but not lateral or basolateral membranes, even in cell types where haemagglutinin was found on all external membranes. Other cytosolic components of the virion either distributed throughout the cytoplasm (NEP/NS2) or did not localise solely to the apical plasma membrane in all cell types (M1). NP localised specifically to the apical surface even when expressed alone, indicating intrinsic targeting. A similar proportion of NP associated with membrane fractions in flotation assays from virus-infected and plasmid-transfected cells. Detergent-resistant flotation at 4 degreesC suggested that these membranes were lipid raft microdomains. Confirming this, cholesterol depletion rendered NP detergent-soluble and furthermore, resulted in its partial redistribution throughout the cell. We conclude that NP is independently targeted to the apical plasma membrane through a mechanism involving lipid rafts and propose that this helps determine the polarity of influenza virus budding.