Highly Basic Clusters in the Herpes Simplex Virus 1 Nuclear Egress Complex Drive Membrane Budding by Inducing Lipid Ordering.
Highly Basic Clusters in the Herpes Simplex Virus 1 Nuclear Egress Complex Drive Membrane Budding by Inducing Lipid Ordering.
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DOI：
10.1128/mbio.01548-21
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发表时间：
2021-08-31
期刊：
影响因子：
6.4
通讯作者：
Heldwein EE
中科院分区：
文献类型：
--
作者：
Thorsen MK;Lai A;Lee MW;Hoogerheide DP;Wong GCL;Freed JH;Heldwein EE
在疱疹病毒的复制过程中，衣壳通过在核膜内出芽而从核逃逸到细胞质中。这个不寻常的过程是由病毒核出口复合物（NEC）介导的，该复合物通过寡聚成六边形的膜结合支架使衣壳周围的膜变形。在这里，我们发现NEC的高碱性近膜区（MPR）通过插入脂质头基来改变脂质顺序并促进负高斯曲率。我们还发现，MPRs和膜之间的静电相互作用是必不可少的膜变形。其中一个MPR在感染期间被病毒激酶磷酸化，并且相应的磷酸模拟突变阻断衣壳核出口。我们发现，相同的磷酸模拟突变破坏NEC膜的相互作用，并抑制NEC介导的体外出芽，提供了一个生物物理解释体内的现象。我们的数据表明，NEC产生负膜曲率的脂质排序和蛋白质支架和磷酸化作为一个关闭开关，抑制NEC的膜出芽活动，以防止capture-less出芽。
During replication of herpesviruses, capsids escape from the nucleus into the cytoplasm by budding at the inner nuclear membrane. This unusual process is mediated by the viral nuclear egress complex (NEC) that deforms the membrane around the capsid by oligomerizing into a hexagonal, membrane-bound scaffold. Here, we found that highly basic membrane-proximal regions (MPRs) of the NEC alter lipid order by inserting into the lipid headgroups and promote negative Gaussian curvature. We also find that the electrostatic interactions between the MPRs and the membranes are essential for membrane deformation. One of the MPRs is phosphorylated by a viral kinase during infection, and the corresponding phosphomimicking mutations block capsid nuclear egress. We show that the same phosphomimicking mutations disrupt the NEC-membrane interactions and inhibit NEC-mediated budding in vitro, providing a biophysical explanation for the in vivo phenomenon. Our data suggest that the NEC generates negative membrane curvature by both lipid ordering and protein scaffolding and that phosphorylation acts as an off switch that inhibits the membrane-budding activity of the NEC to prevent capsid-less budding.