Targeting of Murine Leukemia Virus Gag to the Plasma Membrane Is Mediated by PI(4,5)P2/PS and a Polybasic Region in the Matrix
Targeting of Murine Leukemia Virus Gag to the Plasma Membrane Is Mediated by PI(4,5)P2/PS and a Polybasic Region in the Matrix
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DOI：
10.1128/jvi.01134-09
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发表时间：
2010-01-01
影响因子：
5.4
通讯作者：
Muriaux, D.
中科院分区：
文献类型：
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作者：
Hamard-Peron, E.;Juillard, F.;Muriaux, D.
人类免疫缺陷病毒Gag蛋白的膜靶向性依赖于位于质膜上的磷脂酰肌醇-(4，5)-二磷酸[PI(4，5)P-2]。为了确定进化上遥远的逆转录病毒Gag蛋白是否以类似的机制为靶点，我们构建了小鼠白血病病毒(MuLV)Gag的基质(MA)结构域突变株，体外检测了它们与膜模型的结合，并在细胞培养中分析了它们的表型。在体外，我们发现MA以显著的亲和力结合所有的磷脂酰肌醇磷酸酯，但只有当磷脂酰丝氨酸增强时，MA才对PI(4，5)P-2显示出很强的特异性。MA中多碱区域的突变极大地降低了这种亲和力。在细胞中，在5ptaseIV过表达的条件下，PI(4，5)P-2的缺失强烈地抑制了病毒的产生，并且MA多碱区的突变改变了Gag的定位、膜结合和病毒粒子的产生。我们的结果表明，MA的N-端多碱簇对于GAG靶向质膜是必不可少的。尽管MuLV-MA结构域在结构上不同于人类免疫缺陷病毒1型和2型，并且缺乏易于识别的PI(4，5)P-2结合裂隙，但MA结构域与PI(4，5)P-2的结合似乎是逆转录病毒中的一个保守特征。
Membrane targeting of the human immunodeficiency virus Gag proteins is dependent on phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P-2] located in the plasma membrane. In order to determine if evolutionarily distant retroviral Gag proteins are targeted by a similar mechanism, we generated mutants of the matrix (MA) domain of murine leukemia virus (MuLV) Gag, examined their binding to membrane models in vitro, and analyzed their phenotypes in cell culture. In vitro, we showed that MA bound all the phosphatidylinositol phosphates with significant affinity but displayed a strong specificity for PI(4,5)P-2 only if enhanced by phosphatidylserine. Mutations in the polybasic region in MA dramatically reduced this affinity. In cells, virus production was strongly impaired by PI(4,5)P-2 depletion under conditions of 5ptaseIV overexpression, and mutations in the MA polybasic region altered Gag localization, membrane binding, and virion production. Our results suggest that the N-terminal polybasic cluster of MA is essential for Gag targeting to the plasma membrane. The binding of the MA domain to PI(4,5)P-2 appears to be a conserved feature among retroviruses despite the fact that the MuLV-MA domain is structurally different from that of human immunodeficiency virus types 1 and 2 and lacks a readily identifiable PI(4,5)P-2 binding cleft.