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.
Thorsen, Michael K., et al. "Highly Basic Clusters in the Herpes Simplex Virus 1 Nuclear Egress Complex Drive Membrane Budding by Inducing Lipid Ordering." mBio (Online), vol. 12, no. 4, Aug. 2021. https://doi.org/10.1128/mbio.01548-21
Thorsen, Michael K., Lai, Alex, Lee, Michelle W., Hoogerheide, David P., Wong, Gerard L., Freed, Jack H., & Heldwein, Ekaterina E. (2021). Highly Basic Clusters in the Herpes Simplex Virus 1 Nuclear Egress Complex Drive Membrane Budding by Inducing Lipid Ordering. mBio (Online), 12(4). https://doi.org/10.1128/mbio.01548-21
@article{osti_1903984,
author = {Thorsen, Michael K. and Lai, Alex and Lee, Michelle W. and Hoogerheide, David P. and Wong, Gerard L. and Freed, Jack H. and Heldwein, Ekaterina E.},
title = {Highly Basic Clusters in the Herpes Simplex Virus 1 Nuclear Egress Complex Drive Membrane Budding by Inducing Lipid Ordering},
annote = {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.},
doi = {10.1128/mbio.01548-21},
url = {https://www.osti.gov/biblio/1903984},
journal = {mBio (Online)},
issn = {ISSN 2150-7511},
number = {4},
volume = {12},
place = {United States},
publisher = {American Society for Microbiology (ASM)},
year = {2021},
month = {08}}
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Tufts University, Medford, MA (United States)
Sponsoring Organization:
Howard Hughes Medical Institute; National Institutes of Health (NIH); National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES)
Nystrom, Nicholas A.; Levine, Michael J.; Roskies, Ralph Z.
Proceedings of the 2015 XSEDE Conference on Scientific Advancements Enabled by Enhanced Cyberinfrastructure - XSEDE '15https://doi.org/10.1145/2792745.2792775