Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Viruses. 2012 May;4(5):800-32. doi: 10.3390/v4050800. Epub 2012 May 10.
Herpesviridae comprise a large family of enveloped DNA viruses all of whom employ orthologs of the same three glycoproteins, gB, gH and gL. Additionally, herpesviruses often employ accessory proteins to bind receptors and/or bind the heterodimer gH/gL or even to determine cell tropism. Sorting out how these proteins function has been resolved to a large extent by structural biology coupled with supporting biochemical and biologic evidence. Together with the G protein of vesicular stomatitis virus, gB is a charter member of the Class III fusion proteins. Unlike VSV G, gB only functions when partnered with gH/gL. However, gH/gL does not resemble any known viral fusion protein and there is evidence that its function is to upregulate the fusogenic activity of gB. In the case of herpes simplex virus, gH/gL itself is upregulated into an active state by the conformational change that occurs when gD, the receptor binding protein, binds one of its receptors. In this review we focus primarily on prototypes of the three subfamilies of herpesviruses. We will present our model for how herpes simplex virus (HSV) regulates fusion in series of highly regulated steps. Our model highlights what is known and also provides a framework to address mechanistic questions about fusion by HSV and herpesviruses in general.
疱疹病毒科包含一大类包膜 DNA 病毒，它们都使用相同的三种糖蛋白（gB、gH 和 gL）的同源物。此外，疱疹病毒通常使用辅助蛋白来结合受体和/或结合异源二聚体 gH/gL，甚至决定细胞嗜性。通过结构生物学结合支持的生化和生物学证据，在很大程度上已经解决了这些蛋白的功能。与水疱性口炎病毒的 G 蛋白一样，gB 是 III 类融合蛋白的创始成员。与 VSV G 不同，gB 仅在与 gH/gL 配对时起作用。然而，gH/gL 并不像任何已知的病毒融合蛋白，并且有证据表明它的功能是上调 gB 的融合活性。在单纯疱疹病毒的情况下，gH/gL 本身通过其受体结合蛋白 gD 结合其受体之一时发生的构象变化而被上调到活性状态。在这篇综述中，我们主要关注疱疹病毒的三个亚科的原型。我们将提出我们的模型，说明单纯疱疹病毒 (HSV) 如何通过一系列高度调节的步骤来调节融合。我们的模型突出了已知的内容，并为解决 HSV 和一般疱疹病毒的融合的机制问题提供了一个框架。
