BIOLOGICAL-ACTIVITY OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 VIF REQUIRES MEMBRANE TARGETING BY C-TERMINAL BASIC DOMAINS
BIOLOGICAL-ACTIVITY OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 VIF REQUIRES MEMBRANE TARGETING BY C-TERMINAL BASIC DOMAINS
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DOI：
10.1128/jvi.69.11.7196-7204.1995
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发表时间：
1995-11-01
影响因子：
5.4
通讯作者：
GABUZDA, D
中科院分区：
文献类型：
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作者：
GONCALVES, J;SHI, B;GABUZDA, D
人类免疫缺陷病毒1型(HIV-1)编码一种对病毒复制和传染性至关重要的Vif蛋白。VIF是一种细胞质蛋白，以膜结合和可溶性两种形式存在。膜相关形式是一种外源性膜蛋白，与细胞膜的胞质侧密切相关。我们已经分析了Vif的膜靶向机制及其在HIV-1复制中的作用，突变研究表明，膜结合需要C末端的碱性结构域。破坏膜结合的VIF突变也抑制了HIV-1的复制，表明VIF的膜定位可能是其体内生物活性所必需的。膜的胰酶处理几乎完全取消了Vif的膜结合，这些结果表明Vif的膜定位需要C端的基本结构域并与膜相关蛋白(S)相互作用，这种相互作用可能有助于将Vif定位到特定的细胞位置。由于免疫荧光染色和质膜分级研究表明，Vif主要定位于内部细胞质隔室而不是质膜，Vif的膜靶向机制在某些方面不同于其他外源膜蛋白，如Ras、Src和Marcks，后者利用碱性结构域和脂质修饰来进行膜靶向。Vif的膜靶向可能在HIV-1复制中发挥重要作用，因此可能成为治疗的靶点。
Human immunodeficiency virus type 1 (HIV-1) encodes a Vif protein which is important for virus replication and infectivity. Vif is a cytoplasmic protein which exists in both membrane-associated and soluble forms. The membrane-associated form is an extrinsic membrane protein which is tightly associated with the cytoplasmic side of membranes. We have analyzed the mechanism of membrane targeting of Vif and its role in HIV-1 replication, Mutagenesis studies demonstrate that C-terminal basic domains are required for membrane association. Vif mutations which disrupt membrane association also inhibit HIV-1 replication, indicating that membrane localization of Vif is likely to be required for its biological activity in vivo. Membrane binding of Vif is almost completely abolished by trypsin treatment of membranes, These results demonstrate that membrane localization of Vif requires C-terminal basic domains and interaction with a membrane-associated protein(s), This interaction may serve to direct Vif to a specific cellular site, since immunofluorescence staining and plasma membrane fractionation studies show that Vif is localized predominantly to an internal cytoplasmic compartment rather than to the plasma membrane, The mechanism of membrane targeting of Vif is different in some respects from that of other extrinsic membrane proteins, such as Ras, Src, and MARCKS, which utilize a basic domain together with a lipid modification for membrane targeting. Membrane targeting of Vif is likely to play an important role in HIV-1 replication and thus may be a therapeutic target.