Dynamic organization of Herpesvirus glycoproteins on the viral envelope revealed by super-resolution microscopy

PLoS Pathog. 2019 Dec 2;15(12):e1008209. doi: 10.1371/journal.ppat.1008209. eCollection 2019 Dec.

Abstract

The processes of cell attachment and membrane fusion of Herpes Simplex Virus 1 involve many different envelope glycoproteins. Viral proteins gC and gD bind to cellular receptors. Upon binding, gD activates the gH/gL complex which in turn activates gB to trigger membrane fusion. Thus, these proteins must be located at the point of contact between cellular and viral envelopes to interact and allow fusion. Using super-resolution microscopy, we show that gB, gH/gL and most of gC are distributed evenly round purified virions. In contrast, gD localizes essentially as clusters which are distinct from gB and gH/gL. Upon cell binding, we observe that all glycoproteins, including gD, have a similar ring-like pattern, but the diameter of these rings was significantly smaller than those observed on cell-free viruses. We also observe that contrary to cell-free particles, gD mostly colocalizes with other glycoproteins on cell-bound particles. The differing patterns of localization of gD between cell-free and cell-bound viruses indicates that gD can be reorganized on the viral envelope following either a possible maturation of the viral particle or its adsorption to the cell. This redistribution of glycoproteins upon cell attachment could contribute to initiate the cascade of activations leading to membrane fusion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Glycoproteins / metabolism
  • Glycoproteins / ultrastructure
  • Herpesvirus 1, Human / metabolism*
  • Herpesvirus 1, Human / ultrastructure
  • Humans
  • Microscopy / methods
  • Viral Envelope Proteins / metabolism*
  • Viral Envelope Proteins / ultrastructure
  • Virion / metabolism*
  • Virion / ultrastructure
  • Virus Attachment
  • Virus Internalization

Substances

  • Glycoproteins
  • Viral Envelope Proteins

Grants and funding

This work was funded by the Agence Nationale pour la Recherche (ANR) under grant number ANR-14-CE14-0022. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.