scholarly journals Two Sides to Every Story: Herpes Simplex Type-1 Viral Glycoproteins gB, gD, gH/gL, gK, and Cellular Receptors Function as Key Players in Membrane Fusion

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1849
Author(s):  
Nithya Jambunathan ◽  
Carolyn M. Clark ◽  
Farhana Musarrat ◽  
Vladimir N. Chouljenko ◽  
Jared Rudd ◽  
...  
Keyword(s):  
Herpes Simplex ◽  
Membrane Fusion ◽  
Virus Entry ◽  
Viral Envelope ◽  
Critical Determinant ◽  
Cellular Receptors ◽  
Disease Spectrum ◽  
Viral Glycoproteins ◽  
Hsv 1

Herpes simplex virus type-1 (HSV-1) and type-2 (HSV-2) are prototypical alphaherpesviruses that are characterized by their unique properties to infect trigeminal and dorsal root ganglionic neurons, respectively, and establish life-long latent infections. These viruses initially infect mucosal epithelial tissues and subsequently spread to neurons. They are associated with a significant disease spectrum, including orofacial and ocular infections for HSV-1 and genital and neonatal infections for HSV-2. Viral glycoproteins within the virion envelope bind to specific cellular receptors to mediate virus entry into cells. This is achieved by the fusion of the viral envelope with the plasma membrane. Similarly, viral glycoproteins expressed on cell surfaces mediate cell-to-cell fusion and facilitate virus spread. An interactive complex of viral glycoproteins gB, gD/gH/gL, and gK and other proteins mediate these membrane fusion phenomena with glycoprotein B (gB), the principal membrane fusogen. The requirement for the virion to enter neuronal axons suggests that the heterodimeric protein complex of gK and membrane protein UL20, found only in alphaherpesviruses, constitute a critical determinant for neuronal entry. This hypothesis was substantiated by the observation that a small deletion in the amino terminus of gK prevents entry into neuronal axons while allowing entry into other cells via endocytosis. Cellular receptors and receptor-mediated signaling synergize with the viral membrane fusion machinery to facilitate virus entry and intercellular spread. Unraveling the underlying interactions among viral glycoproteins, envelope proteins, and cellular receptors will provide new innovative approaches for antiviral therapy against herpesviruses and other neurotropic viruses.

scholarly journals Comprehensive Characterization of Extracellular Herpes Simplex Virus Type 1 Virions

2008 ◽  
Vol 82 (17) ◽  
pp. 8605-8618 ◽  
Author(s):  
Sandra Loret ◽  
Ginette Guay ◽  
Roger Lippé
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Viral Envelope ◽  
Host Proteins ◽  
Viral Glycoproteins ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT The herpes simplex virus type 1 (HSV-1) genome is contained in a capsid wrapped by a complex tegument layer and an external envelope. The poorly defined tegument plays a critical role throughout the viral life cycle, including delivery of capsids to the nucleus, viral gene expression, capsid egress, and acquisition of the viral envelope. Current data suggest tegumentation is a dynamic and sequential process that starts in the nucleus and continues in the cytoplasm. Over two dozen proteins are assumed to be or are known to ultimately be added to virions as tegument, but its precise composition is currently unknown. Moreover, a comprehensive analysis of all proteins found in HSV-1 virions is still lacking. To better understand the implication of the tegument and host proteins incorporated into the virions, highly purified mature extracellular viruses were analyzed by mass spectrometry. The method proved accurate (95%) and sensitive and hinted at 8 different viral capsid proteins, 13 viral glycoproteins, and 23 potential viral teguments. Interestingly, four novel virion components were identified (UL7, UL23, UL50, and UL55), and two teguments were confirmed (ICP0 and ICP4). In contrast, UL4, UL24, the UL31/UL34 complex, and the viral UL15/UL28/UL33 terminase were undetected, as was most of the viral replication machinery, with the notable exception of UL23. Surprisingly, the viral glycoproteins gJ, gK, gN, and UL43 were absent. Analyses of virions produced by two unrelated cell lines suggest their protein compositions are largely cell type independent. Finally, but not least, up to 49 distinct host proteins were identified in the virions.

scholarly journals Characterization of Vesicular Stomatitis Virus Pseudotypes Bearing Essential Entry Glycoproteins gB, gD, gH, and gL of Herpes Simplex Virus 1

2016 ◽  
Vol 90 (22) ◽  
pp. 10321-10328 ◽  
Author(s):  
Henry B. Rogalin ◽  
Ekaterina E. Heldwein
Keyword(s):  
Herpes Simplex ◽  
Membrane Fusion ◽  
Viral Envelope ◽  
Herpes Simplex Virus 1 ◽  
Herpes Simplex Viruses ◽  
Systematic Exploration ◽  
Vesicular Stomatitis ◽  
Simplex Virus ◽  
First Time ◽  
Hsv 1

ABSTRACTHerpes simplex viruses (HSVs) are unusual in that unlike most enveloped viruses, they require at least four entry glycoproteins, gB, gD, gH, and gL, for entry into target cells in addition to a cellular receptor for gD. The dissection of the herpes simplex virus 1 (HSV-1) entry mechanism is complicated by the presence of more than a dozen proteins on the viral envelope. To investigate HSV-1 entry requirements in a simplified system, we generated vesicular stomatitis virus (VSV) virions pseudotyped with HSV-1 essential entry glycoproteins gB, gD, gH, and gL but lacking the native VSV fusogen G. These virions, referred to here as VSVΔG-BHLD virions, infected a cell line expressing a gD receptor, demonstrating for the first time that the four essential entry glycoproteins of HSV-1 are not only required but also sufficient for cell entry. To our knowledge, this is the first time the VSV pseudotyping system has been successfully extended beyond two proteins. Entry of pseudotyped virions required a gD receptor and was inhibited by HSV-1 specific anti-gB or anti-gH/gL neutralizing antibodies, which suggests that membrane fusion during the entry of the pseudotyped virions shares common requirements with the membrane fusion involved in HSV-1 entry and HSV-1-mediated syncytium formation. The HSV pseudotyping system established in this study presents a novel tool for systematic exploration of the HSV entry and membrane fusion mechanisms.IMPORTANCEHerpes simplex viruses (HSVs) are human pathogens that can cause cold sores, genital herpes, and blindness. No vaccines or preventatives are available. HSV entry into cells—a prerequisite for a successful infection—is a complex process that involves multiple viral and host proteins and occurs by different routes. Detailed mechanistic knowledge of the HSV entry is important for understanding its pathogenesis and would benefit antiviral and vaccine development, yet the presence of more than a dozen proteins on the viral envelope complicates the dissection of the HSV entry mechanisms. In this study, we generated heterologous virions displaying the four essential entry proteins of HSV-1 and showed that they are capable of cell entry and, like HSV-1, require all four entry glycoproteins along with a gD receptor. This HSV pseudotyping system pioneered in this work opens doors for future systematic exploration of the herpesvirus entry mechanisms.

scholarly journals The Ig-Like V-Type Domain of Paired Ig-Like Type 2 Receptor Alpha Is Critical for Herpes Simplex Virus Type 1-Mediated Membrane Fusion

2010 ◽  
Vol 84 (17) ◽  
pp. 8664-8672 ◽  
Author(s):  
Qing Fan ◽  
Richard Longnecker
Keyword(s):  
Amino Acid ◽  
Herpes Simplex ◽  
Membrane Fusion ◽  
Fusion Activity ◽  
Acid Protein ◽  
Simplex Virus ◽  
Amino Acid Protein ◽  
Hsv 1

ABSTRACT Paired immunoglobulin (Ig)-like type 2 receptor alpha (PILRα) and PILRβ are paired receptors that are highly homologous to each other. When engaged by ligand, PILRα is inhibitory whereas PILRβ is activating. PILRα is a newly identified herpes simplex virus type 1 (HSV-1) glycoprotein B (gB) receptor and is associated with membrane fusion and entry activity of HSV-1. PILRα is a 303-amino-acid protein with an Ig-like V (variable)-type domain from amino acid 31 to 150, whereas PILRβ is a 217-amino-acid protein with an Ig-like V-type domain from amino acid 21 to 143. We report that PILRβ is not a receptor for HSV-1 and HSV-2. Domain swaps between PILRα and PILRβ reveal that the Ig-like V-type domain of PILRα, but not PILRβ, plays a critical role in cell membrane fusion activity and the binding of PILRα to gB. Individual replacement of 13 amino acids in PILRα showed that most of these mutations had no effect on cell fusion activity. However, mutation of the tryptophan residue at amino acid 139 significantly impaired cell fusion activity for HSV-1 and eliminated binding to gB.

scholarly journals Coiled-Coil Domains in Glycoproteins B and H Are Involved in Human Cytomegalovirus Membrane Fusion

2004 ◽  
Vol 78 (15) ◽  
pp. 8333-8341 ◽  
Author(s):  
Matthew Lopper ◽  
Teresa Compton
Keyword(s):  
Membrane Fusion ◽  
Human Cytomegalovirus ◽  
Virus Entry ◽  
Coiled Coil ◽  
Coiled Coils ◽  
Viral Envelope ◽  
Heptad Repeat ◽  
Repeat Sequences ◽  
Human Cmv ◽  
Hsv 1

ABSTRACT Human cytomegalovirus (CMV) utilizes a complex route of entry into cells that involves multiple interactions between viral envelope proteins and cellular receptors. Three conserved viral glycoproteins, gB, gH, and gL, are required for CMV-mediated membrane fusion, but little is known of how these proteins cooperate during entry (E. R. Kinzler and T. Compton, submitted for publication). The goal of this study was to begin defining the molecular mechanisms that underlie membrane fusion mediated by herpesviruses. We identified heptad repeat sequences predicted to form alpha-helical coiled coils in two glycoproteins required for fusion, gB and gH. Peptides derived from gB and gH containing the heptad repeat sequences inhibited virus entry when introduced coincident with virus inoculation onto cells or when mixed with virus prior to inoculation. Neither peptide affected binding of CMV to fibroblasts, suggesting that the peptides inhibit membrane fusion. Both gB and gH coiled-coil peptides blocked entry of several laboratory-adapted and clinical strains of human CMV, but neither peptide affected entry of murine CMV or herpes simplex virus type 1 (HSV-1). Although murine CMV and HSV-1 gB and gH have heptad repeat regions, the ability of human CMV gB and gH peptides to inhibit virus entry correlates with the specific residues that comprise the heptad repeat region. The ability of gB and gH coiled-coil peptides to inhibit virus entry independently of cell contact suggests that the coiled-coil regions of gB and gH function differently from those of class I, single-component fusion proteins. Taken together, these data support a critical role for alpha-helical coiled coils in gB and gH in the entry pathway of CMV.

scholarly journals Harringtonine Inhibits Herpes Simplex Virus Type 1 Infection by Reducing Herpes Virus Entry Mediator Expression

2021 ◽  
Vol 12 ◽  
Author(s):  
Ye Liu ◽  
Qiao You ◽  
Fang Zhang ◽  
Deyan Chen ◽  
Zhenping Huang ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Virus Entry ◽  
Resistant Strains ◽  
Herpès Virus ◽  
Simplex Virus ◽  
Hsv 1

Herpes simplex virus type 1 (HSV-1) infection induces various clinical disorders, such as herpes simplex encephalitis (HSE), herpes simplex keratitis (HSK), and genital herpes. In clinical intervention, acyclovir (ACV) is the major therapeutic drug used to suppress HSV-1; however, ACV-resistant strains have gradually increased. In the present study, harringtonine (HT) significantly inhibited infection of HSV-1 as well as two ACV-resistant strains, including HSV-1 blue and HSV-1 153. Time-of-drug addition assay further revealed that HT mainly reduced the early stage of HSV-1 infection. We also demonstrated that HT mainly affected herpes virus entry mediator (HVEM) expression as shown by qPCR, Western Blot, and Immunofluorescence. Collectively, HT showed antiviral activity against HSV-1 and ACV-resistant strains by targeting HVEM and could be a promising therapeutic candidate for mitigating HSV-1-induced-pathogenesis.

scholarly journals Herpes Simplex Virus 1 Enters Human Keratinocytes by a Nectin-1-Dependent, Rapid Plasma Membrane Fusion Pathway That Functions at Low Temperature

2016 ◽  
Vol 90 (22) ◽  
pp. 10379-10389 ◽  
Author(s):  
Charlotte L. Sayers ◽  
Gillian Elliott
Keyword(s):  
Plasma Membrane ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Low Temperature ◽  
Membrane Fusion ◽  
Virus Entry ◽  
Herpes Simplex Virus 1 ◽  
Human Keratinocyte ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACTHerpes simplex virus 1 (HSV-1) infects humans through stratified epithelia that are composed primarily of keratinocytes. The route of HSV-1 entry into keratinocytes has been the subject of limited investigation, but it is proposed to involve pH-dependent endocytosis, requiring the gD-binding receptor nectin-1. Here, we have utilized the nTERT human keratinocyte cell line as a new model for dissecting the mechanism of HSV-1 entry into the host. Although immortalized, these cells nonetheless retain normal growth and differentiation properties of primary cells. Using short interfering RNA (siRNA) depletion studies, we confirm that, despite nTERT cells expressing high levels of the alternative gD receptor HVEM, HSV-1 requires nectin-1, not HVEM, to enter these cells. Strikingly, virus entry into nTERT cells occurred with unusual rapidity, such that maximum penetration was achieved within 5 min. Moreover, HSV-1 was able to enter keratinocytes but not other cell types at temperatures as low as 7°C, conditions where endocytosis was shown to be completely inhibited. Transmission electron microscopy of early entry events at both 37°C and 7°C identified numerous examples of naked virus capsids located immediately beneath the plasma membrane, with no evidence of virions in cytoplasmic vesicles. Taken together, these results imply that HSV-1 uses the nectin-1 receptor to enter human keratinocyte cells via a previously uncharacterized rapid plasma membrane fusion pathway that functions at low temperature. These studies have important implications for current understanding of the relationship between HSV-1 and its relevantin vivotarget cell.IMPORTANCEThe gold standard of antiviral treatment for any human virus infection is the prevention of virus entry into the host cell. In the case of HSV-1, primary infection in the human begins in the epidermis of the skin or the oral mucosa, where the virus infects keratinocytes, and it is therefore important to understand the molecular events involved in HSV-1 entry into this cell type. Nonetheless, few studies have looked specifically at entry into these relevant human cells. Our results reveal a new route for virus entry that is specific to keratinocytes, involves rapid entry, and functions at low temperatures. This may reflect the environmental conditions encountered by HSV-1 when entering its host through the skin and emphasizes the importance of studying virus-host interactions in physiologically relevant cells.

scholarly journals Syncytial Phenotype of C-Terminally Truncated Herpes Simplex Virus Type 1 gB Is Associated with Diminished Membrane Interactions

2010 ◽  
Vol 84 (10) ◽  
pp. 4923-4935 ◽  
Author(s):  
Tirumala Kumar Chowdary ◽  
Ekaterina E. Heldwein
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Membrane Fusion ◽  
Herpes Simplex Virus Type ◽  
Lipid Membranes ◽  
Helical Structure ◽  
Cytoplasmic Domain ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT The cytoplasmic domain of glycoprotein B (gB) from herpes simplex virus type 1 (HSV-1) is an important regulator of membrane fusion. C-terminal truncations of the cytoplasmic domain lead to either hyperfusion or fusion-null phenotypes. Currently, neither the structure of the cytoplasmic domain nor its mechanism of fusion regulation is known. Here we show, for the first time, that the full-length cytoplasmic domain of HSV-1 gB associates stably with lipid membranes, preferentially binding to membranes containing anionic head groups. This interaction involves a large increase in helical content. However, the truncated cytoplasmic domains associated with the hyperfusion phenotype show a small increase in helical structure and a diminished association with lipid membranes, whereas the one associated with the fusion-null phenotype shows no increase in helical structure and only a minimal association with lipid membranes. We hypothesize that stable binding to lipid membranes is an important part of the mechanism by which the cytoplasmic domain negatively regulates membrane fusion. Moreover, our experiments with truncated cytoplasmic domains point to two specific regions that are critical for membrane interactions. Taken together, our work provides several important new insights into the architecture of the cytoplasmic domain of HSV-1 gB and its interaction with lipid membranes.

Nucleotide sequences of herpes simplex virus type 1 (HSV-1) affecting virus entry, cell fusion, and production of glycoprotein gB (VP7)

Virology ◽  
1982 ◽  
Vol 122 (2) ◽  
pp. 411-423 ◽  
Author(s):  
Neal DeLuca ◽  
David J. Bzik ◽  
Vincent C. Bond ◽  
Stanley Person ◽  
Wallace Snipes
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Cell Fusion ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Virus Entry ◽  
Nucleotide Sequences ◽  
Simplex Virus ◽  
Hsv 1

scholarly journals Glycoproteins Required for Entry Are Not Necessary for Egress of Pseudorabies Virus

2008 ◽  
Vol 82 (13) ◽  
pp. 6299-6309 ◽  
Author(s):  
Barbara Klupp ◽  
Jan Altenschmidt ◽  
Harald Granzow ◽  
Walter Fuchs ◽  
Thomas C. Mettenleiter
Keyword(s):  
Nuclear Membrane ◽  
Pseudorabies Virus ◽  
Virus Entry ◽  
Viral Envelope ◽  
Detectable Effect ◽  
Nuclear Egress ◽  
Viral Glycoproteins ◽  
Simplex Virus

ABSTRACT In the current perception of the herpesvirus replication cycle, two fusion processes are thought to occur during entry and nuclear egress. For penetration, glycoproteins gB and gH/gL have been shown to be essential, whereas a possible role of these glycoproteins in nuclear egress remains unclear. Viral envelope glycoproteins have been detected by immunolabeling in the nuclear membrane as well as in primary enveloped particles in several herpesviruses, indicating that they might be involved in the fusion process. Moreover, a herpes simplex virus type 1 mutant simultaneously lacking gB and gH was described to be deficient in nuclear egress (A. Farnsworth, T. W. Wisner, M. Webb, R. Roller, G. Cohen, R. Eisenberg, and D. C. Johnson, Proc. Natl. Acad. Sci. USA 104:10187-10192, 2007). To analyze the situation in the related alphaherpesvirus pseudorabies virus (PrV), mutants carrying single and double deletions of glycoproteins gB, gD, gH, and gL were constructed and characterized. We show here that the simultaneous deletion of gB and gD, gB and gH, gD and gH, or gH and gL has no detectable effect on PrV egress, implying that none of these glycoproteins either singly or in the tested combinations is required for nuclear egress. In addition, immunolabeling studies using different mono- or polyclonal sera raised against various PrV glycoproteins did not reveal the presence of viral glycoproteins in the inner nuclear membrane or in primary virions. Thus, our data strongly suggest that different fusion mechanisms are active during virus entry and egress.

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