Specific Association of Glycoprotein B with Lipid Rafts during Herpes Simplex Virus Entry

Abstract

Herpes simplex virus (HSV) entry requires the interaction of glycoprotein D (gD) with a cellular receptor such as herpesvirus entry mediator (HVEM or HveA) or nectin-1 (HveC). However, the fusion mechanism is still not understood. Since cholesterol-enriched cell membrane lipid rafts are involved in the entry of other enveloped viruses such as human immunodeficiency virus and Ebola virus, we tested whether HSV entry proceeds similarly. Vero cells and cells expressing either HVEM or nectin-1 were treated with cholesterolsequestering drugs such as methyl-␤-cyclodextrin or nystatin and then exposed to virus. In all cases, virus entry was inhibited in a dose-dependent manner, and the inhibitory effect was fully reversible by replenishment of cholesterol. To examine the association of HVEM and nectin-1 with lipid rafts, we analyzed whether they partitioned into nonionic detergent-insoluble glycolipid-enriched membranes (DIG). There was no constitutive association of either receptor with DIG. Binding of soluble gD or virus to cells did not result in association of nectin-1 with the raft-containing fractions. However, during infection, a fraction of gB but not gC, gD, or gH associated with DIG. Similarly, when cells were incubated with truncated soluble glycoproteins, soluble gB but not gC was found associated with DIG. Together, these data favor a model in which HSV uses gB to rapidly mobilize lipid rafts that may serve as a platform for entry and cell signaling. It also suggests that gB may interact with a cellular molecule associated with lipid rafts.

Copatching and Lipid Raft Association of Different Viral Glycoproteins Expressed on the Surfaces of Pseudorabies Virus-Infected Cells

“…By using detergent solubilization experiments, HSV gB (but not gC, gD, or gH) has been shown to localize to raft fractions during virus entry (2). These findings seem to be consistent with our present findings which suggest that PRV gB shows a strong, detergent-resistant raft association whereas gC and gD show a weak, detergent-sensitive raft association in infected cells.…”

“…These findings seem to be consistent with our present findings which suggest that PRV gB shows a strong, detergent-resistant raft association whereas gC and gD show a weak, detergent-sensitive raft association in infected cells. Interestingly, those researchers suggest that the ectodomain of gB is responsible for the gB association with rafts, suggesting that gB may interact, via its ectodomain, with a raft-residing protein (2). The HSV type 1 vhs tegument protein and, to a lesser extent, gH glycoprotein have also been shown to be associated with rafts in infected cells (26).…”

“…Lipid rafts are enriched in glycosyl-phosphatidylinositol-linked proteins, specific transmembrane proteins, signal transduction molecules, and the ganglioside GM1. Recently it has been shown that the HSV gB glycoprotein, as well as two HSV tegument-membrane proteins (vhs and UL56), are lipid raft associated in infected cells or become lipid raft associated during virus entry (2,24,26).…”

A serum-free Vero production platform for a chimeric virus vaccine candidate

“…The underlying mechanisms for these observed process improvements are not known. However, accumulated evidence indicates that several viruses, including RSV, utilize plasma membrane microdomains-called lipid rafts-for virus assembly and budding (Bender et al 2003; Brown …”

Role of Membrane Rafts in Viral Infection

“…In addition to its role in entry of non enveloped the role of membrane rafts in entry of enveloped viruses has been investigated in studies using influenza virus (Orthomyxoviridae) [57][58][59][60][61], human immunodeficiency virus type 1 (HIV-1; Retroviridae) [62][63][64][65][66][67], human T lymphotropic virus 1 (HTLV-1; Retroviridae) [68,69], Ebola virus (Filoviridae) [70], Marburg virus (Filoviridae) [70,71], Epstein-Barr virus (EBV; herpesviridae) [72,73], herpes simplex virus-1 (HSV-1; herpesviridae) [74] including porcine herpesvirus-1 pseudorabies virus [75], human herpesvirus-6 (HHV-6; Herpesviridae) [76], human herpesvirus-8 (HHV-8; Herpesviridae) [77], vaccinia virus (Poxviridae) [78], coronavirus including severe acute respiratory syndrome coronavirus (SARS-CoV; Coronaviridae) [79][80][81][82][83][84][85], West Nile virus (WNV; Flaviviridae) [86], dengue virus (DEN; Flaviviridae) [87][88][89], Japanese encephalitis virus (JEV; Flaviviridae) [89], human hepatitis C virus (HCV; Flaviviridae) [90,91], Semliki Forest virus (Togaviridae) [92][93][94][95], Sindbis virus (Togaviridae) …”