Localization of the Interaction Site of Herpes Simplex Virus Glycoprotein D (gD) on the Membrane Fusion Regulator, gH/gL
Localization of the Interaction Site of Herpes Simplex Virus Glycoprotein D (gD) on the Membrane Fusion Regulator, gH/gL
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DOI：
10.1128/jvi.00983-20
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发表时间：
2020-10-01
影响因子：
5.4
通讯作者：
Cohen, Gary H.
中科院分区：
文献类型：
--
作者：
Cairns, Tina M.;Atanasiu, Doina;Cohen, Gary H.
四种单纯疱疹病毒 (HSV) 糖蛋白（gD、gH/gL 和 gB）之间的一系列蛋白质-蛋白质相互作用驱动 HSV 包膜和宿主膜之间的融合，从而允许病毒进入和感染。具体来说，gD 与其受体之一的结合会诱导构象变化，使 gD 与调节复合物 gH/gL 结合，然后激活融合剂 gB，导致膜融合。使用表面等离振子共振和一组空间阻断相互作用的抗gD单克隆抗体（MAb），我们之前表明gH/gL在不同于gD受体结合位点的位点直接与gD结合。在这里，使用类似的策略，我们首先评估了一组未表征的抗 gH/gL MAb 阻断与 gD 结合和/或抑制融合的能力。我们发现四个 gD-gH/gL 阻断 MAb 的表位位于 gH N 末端和 gL C 末端的灵活区域内，而第五个表位位于 gL 残基 77 周围。总之，我们的数据将 gH/gL 上的 gD 结合区域定位到异二聚体膜远端区域的一组 gH 和 gL 残基。令人惊讶的是，第二组 MAb 并未阻断 gD-gH/gL 结合，而是通过改变动力学结合来稳定复合物。然而，尽管 gD-gH/gL 相互作用延长，但“稳定”MAb 也会抑制细胞与细胞的融合，这表明有一种独特的机制可以停止融合过程。我们的研究结果支持以 gD-gH/gL 相互作用为目标，以防止 HSV 治疗和疫苗策略中的融合。 重要性 开发人类 HSV 疫苗的关键是了解参与进入的病毒颗粒糖蛋白。 HSV 利用多种糖蛋白进行附着、受体相互作用和膜融合。确定这些蛋白质的功能部分是通过结构生物学结合免疫学和生物学证据来解决的。结合后，病毒体 gD 与受体相互作用，激活调节器 gH/gL 复合物，触发 gB 驱动融合。仍然存在多个问题，其中之一是每个糖蛋白相互作用位点的物理位置。使用具有已知表位的保护性抗体，我们记录了长期以来寻找的 gD 和 gH/gL 之间的相互作用，详细说明了 gD 上对于创建 gD-gH/gL 三链体重要的区域。现在，我们已经确定了 gH/gL 上相应的 gD 接触位点。同时，我们发现了一种新机制，gH/gL 抗体可以稳定复合物并抑制融合进程。我们的 gD-gH/gL 三链体模型为研究融合提供了一个新框架，该框架确定了疫苗开发的目标。
A cascade of protein-protein interactions between four herpes simplex virus (HSV) glycoproteins (gD, gH/gL, and gB) drive fusion between the HSV envelope and host membrane, thereby allowing for virus entry and infection. Specifically, binding of gD to one of its receptors induces a conformational change that allows gD to bind to the regulatory complex gH/gL, which then activates the fusogen gB, resulting in membrane fusion. Using surface plasmon resonance and a panel of anti-gD monoclonal antibodies (MAbs) that sterically blocked the interaction, we previously showed that gH/gL binds directly to gD at sites distinct from the gD receptor binding site. Here, using an analogous strategy, we first evaluated the ability of a panel of uncharacterized anti-gH/gL MAbs to block binding to gD and/or inhibit fusion. We found that the epitopes of four gD-gH/gL-blocking MAbs were located within flexible regions of the gH N terminus and the gL C terminus, while the fifth was placed around gL residue 77. Taken together, our data localized the gD binding region on gH/gL to a group of gH and gL residues at the membrane distal region of the heterodimer. Surprisingly, a second set of MAbs did not block gD-gH/gL binding but instead stabilized the complex by altering the kinetic binding. However, despite this prolonged gD-gH/gL interaction, "stabilizing" MAbs also inhibited cell-cell fusion, suggesting a unique mechanism by which the fusion process is halted. Our findings support targeting the gD-gH/gL interaction to prevent fusion in both therapeutic and vaccine strategies against HSV.IMPORTANCE Key to developing a human HSV vaccine is an understanding of the virion glycoproteins involved in entry. HSV employs multiple glycoproteins for attachment, receptor interaction, and membrane fusion. Determining how these proteins function was resolved, in part, by structural biology coupled with immunological and biologic evidence. After binding, virion gD interacts with a receptor to activate the regulator gH/gL complex, triggering gB to drive fusion. Multiple questions remain, one being the physical location of each glycoprotein interaction site. Using protective antibodies with known epitopes, we documented the long-sought interaction between gD and gH/gL, detailing the region on gD important to create the gD-gH/gL triplex. Now, we have identified the corresponding gD contact sites on gH/gL. Concurrently we discovered a novel mechanism whereby gH/gL antibod-ies stabilize the complex and inhibit fusion progression. Our model for the gD-gH/gL triplex provides a new framework for studying fusion, which identifies targets for vaccine development.