The structural basis of herpesvirus entry

Abstract

Herpesviruses are ubiquitous, double-stranded DNA, enveloped viruses that establish lifelong infections and cause a range of diseases. Entry into host cells requires binding of the virus to specific receptors, followed by the coordinated action of multiple viral entry glycoproteins to trigger membrane fusion. Although the core fusion machinery is conserved for all herpesviruses, each species uses distinct receptors and receptor-binding glycoproteins. Structural studies of the prototypical herpesviruses herpes simplex virus 1 (HSV-1), HSV-2, human cytomegalovirus (HCMV) and Epstein–Barr virus (EBV) entry glycoproteins have defined the interaction sites for glycoprotein complexes and receptors, and have revealed conformational changes that occur on receptor binding. Recent crystallography and electron microscopy studies have refined our model of herpesvirus entry into cells, clarifying both the conserved features and the unique features. In this Review, we discuss recent insights into herpesvirus entry by analysing the structures of entry glycoproteins, including the diverse receptor-binding glycoproteins (HSV-1 glycoprotein D (gD), EBV glycoprotein 42 (gp42) and HCMV gH–gL–gO trimer and gH–gL–UL128–UL130–UL131A pentamer), as well gH–gL and the fusion protein gB, which are conserved in all herpesviruses.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Fig. 1: Model of the herpesvirus entry mechanism.
Fig. 2: Herpes simplex virus 1 glycoprotein D crystal structures.
Fig. 3: Epstein–Barr virus glycoprotein 42 structures.
Fig. 4: Structures of human cytomegalovirus glycoprotein H–glycoprotein L complexes.
Fig. 5: Crystal structures of the glycoprotein H–glycoprotein L complex.
Fig. 6: Glycoprotein B structures.

References

  1. 1.

    Vallbracht, M., Backovic, M., Klupp, B. G., Rey, F. A. & Mettenleiter, T. C. Common characteristics and unique features: a comparison of the fusion machinery of the alphaherpesviruses Pseudorabies virus and Herpes simplex virus. Adv. Virus Res. 104, 225–281 (2019).

    CAS  PubMed  Article  Google Scholar 

  2. 2.

    Mohl, B. S., Chen, J. & Longnecker, R. Gammaherpesvirus entry and fusion: a tale how two human pathogenic viruses enter their host cells. Adv. Virus Res. 104, 313–343 (2019).

    PubMed  Article  CAS  Google Scholar 

  3. 3.

    Nishimura, M. & Mori, Y. Entry of betaherpesviruses. Adv. Virus Res. 104, 283–312 (2019).

    CAS  PubMed  Article  Google Scholar 

  4. 4.

    Atanasiu, D., Saw, W. T., Cohen, G. H. & Eisenberg, R. J. Cascade of events governing cell-cell fusion induced by herpes simplex virus glycoproteins gD, gH/gL, and gB. J. Virol. 84, 12292–12299 (2010).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  5. 5.

    Nicola, A. V. Herpesvirus entry into host cells mediated by endosomal low pH. Traffic 17, 965–975 (2016).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  6. 6.

    Gerna, G., Baldanti, F. & Revello, M. G. Pathogenesis of human cytomegalovirus infection and cellular targets. Hum. Immunol. 65, 381–386 (2004).

    CAS  PubMed  Article  Google Scholar 

  7. 7.

    Ryckman, B. J., Jarvis, M. A., Drummond, D. D., Nelson, J. A. & Johnson, D. C. Human cytomegalovirus entry into epithelial and endothelial cells depends on genes UL128 to UL150 and occurs by endocytosis and low-pH fusion. J. Virol. 80, 710–722 (2006).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  8. 8.

    Compton, T., Nepomuceno, R. R. & Nowlin, D. M. Human cytomegalovirus penetrates host cells by pH-independent fusion at the cell surface. Virology 191, 387–395 (1992).

    CAS  PubMed  Article  Google Scholar 

  9. 9.

    Hutt-Fletcher, L. M. Epstein-Barr virus entry. J. Virol. 81, 7825–7832 (2007).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  10. 10.

    Miller, N. & Hutt-Fletcher, L. M. Epstein-Barr virus enters B cells and epithelial cells by different routes. J. Virol. 66, 3409–3414 (1992).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  11. 11.

    Di Giovine, P. et al. Structure of herpes simplex virus glycoprotein D bound to the human receptor nectin-1. PLoS Pathog. 7, e1002277 (2011).

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  12. 12.

    Krummenacher, C. et al. Structure of unliganded HSV gD reveals a mechanism for receptor-mediated activation of virus entry. EMBO J. 24, 4144–4153 (2005). Compares the crystal structure of unbound HSV-1 gD with that of the previously determined gD–HVEM complex, revealing a conformational change that occurs on receptor-binding.

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  13. 13.

    Carfi, A. et al. Herpes simplex virus glycoprotein D bound to the human receptor HveA. Mol. Cell 8, 169–179 (2001).

    CAS  PubMed  Article  Google Scholar 

  14. 14.

    Mullen, M. M., Haan, K. M., Longnecker, R. & Jardetzky, T. S. Structure of the Epstein-Barr virus gp42 protein bound to the MHC class II receptor HLA-DR1. Mol. Cell 9, 375–385 (2002).

    CAS  PubMed  Article  Google Scholar 

  15. 15.

    Kirschner, A. N., Sorem, J., Longnecker, R. & Jardetzky, T. S. Structure of Epstein-Barr virus glycoprotein 42 suggests a mechanism for triggering receptor-activated virus entry. Structure 17, 223–233 (2009).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  16. 16.

    Sathiyamoorthy, K. et al. Structural basis for Epstein-Barr virus host cell tropism mediated by gp42 and gHgL entry glycoproteins. Nat. Commun. 7, 13557 (2016). Reports the crystal structure of the EBV gp42–gH–gL complex, demonstrating that the N terminus of gp42 spans the length of gH.

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  17. 17.

    Chandramouli, S. et al. Structural basis for potent antibody-mediated neutralization of human cytomegalovirus. Sci. Immunol. https://doi.org/10.1126/sciimmunol.aan1457 (2017). Reports the crystal structure of the HCMV pentamer, demonstrating that HCMV gH–gL folds similarly to EBV gH–gL and UL128–UL130–UL131A binds to an extension in gL.

    Article  PubMed  Google Scholar 

  18. 18.

    Ciferri, C. et al. Structural and biochemical studies of HCMV gH/gL/gO and Pentamer reveal mutually exclusive cell entry complexes. Proc. Natl Acad. Sci. USA 112, 1767–1772 (2015). EM reconstructions of the HCMV trimer and pentamer complexes demonstrate that both gO and UL128–UL130–UL131A dock at the tip of gH–gL.

    CAS  PubMed  Article  Google Scholar 

  19. 19.

    Martinez-Martin, N. et al. An unbiased screen for human cytomegalovirus identifies neuropilin-2 as a central viral receptor. Cell 174, 1158–1171 e1119 (2018). Identifies NRP2 as an HCMV receptor and shows that this receptor binds to the distal end of the pentamer by EM reconstruction.

    CAS  PubMed  Article  Google Scholar 

  20. 20.

    Kabanova, A. et al. Platelet-derived growth factor-alpha receptor is the cellular receptor for human cytomegalovirus gHgLgO trimer. Nat. Microbiol. 1, 16082 (2016). Identifies PDGFRα as an HCMV receptor and shows that this receptor binds to the distal end of the trimer by EM.

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  21. 21.

    Szakonyi, G. et al. Structure of the Epstein-Barr virus major envelope glycoprotein. Nat. Struct. Mol. Biol. 13, 996–1001 (2006).

    CAS  PubMed  Article  Google Scholar 

  22. 22.

    Oliver, S. L., Yang, E. & Arvin, A. M. Varicella-zoster virus glycoproteins: entry, replication, and pathogenesis. Curr. Clin. Microbiol. Rep. 3, 204–215 (2016).

    PubMed  PubMed Central  Article  Google Scholar 

  23. 23.

    Geraghty, R. J., Krummenacher, C., Cohen, G. H., Eisenberg, R. J. & Spear, P. G. Entry of alphaherpesviruses mediated by poliovirus receptor-related protein 1 and poliovirus receptor. Science 280, 1618–1620 (1998).

    CAS  PubMed  Article  Google Scholar 

  24. 24.

    Krummenacher, C. et al. Comparative usage of herpesvirus entry mediator A and nectin-1 by laboratory strains and clinical isolates of herpes simplex virus. Virology 322, 286–299 (2004).

    CAS  PubMed  Article  Google Scholar 

  25. 25.

    Warner, M. S. et al. A cell surface protein with herpesvirus entry activity (HveB) confers susceptibility to infection by mutants of herpes simplex virus type 1, herpes simplex virus type 2, and pseudorabies virus. Virology 246, 179–189 (1998).

    CAS  PubMed  Article  Google Scholar 

  26. 26.

    Montgomery, R. I., Warner, M. S., Lum, B. J. & Spear, P. G. Herpes simplex virus-1 entry into cells mediated by a novel member of the TNF/NGF receptor family. Cell 87, 427–436 (1996).

    CAS  PubMed  Article  Google Scholar 

  27. 27.

    Shukla, D. et al. A novel role for 3-O-sulfated heparan sulfate in herpes simplex virus 1 entry. Cell 99, 13–22 (1999).

    CAS  PubMed  Article  Google Scholar 

  28. 28.

    Lee, C. C. et al. Structural basis for the antibody neutralization of herpes simplex virus. Acta Crystallogr. D Biol. Crystallogr. 69, 1935–1945 (2013).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  29. 29.

    Li, A. et al. Structural basis of nectin-1 recognition by pseudorabies virus glycoprotein D. PLoS Pathog. 13, e1006314 (2017).

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  30. 30.

    Lu, G. et al. Crystal structure of herpes simplex virus 2 gD bound to nectin-1 reveals a conserved mode of receptor recognition. J. Virol. 88, 13678–13688 (2014).

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  31. 31.

    Connolly, S. A. et al. Glycoprotein D homologs in herpes simplex virus type 1, pseudorabies virus, and bovine herpes virus type 1 bind directly to human HveC (nectin-1) with different affinities. Virology 280, 7–18 (2001).

    CAS  PubMed  Article  Google Scholar 

  32. 32.

    Krummenacher, C. et al. Herpes simplex virus glycoprotein D can bind to poliovirus receptor-related protein 1 or herpesvirus entry mediator, two structurally unrelated mediators of virus entry. J. Virol. 72, 7064–7074 (1998).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  33. 33.

    Whitbeck, J. C. et al. The major neutralizing antigenic site on herpes simplex virus glycoprotein D overlaps a receptor-binding domain. J. Virol. 73, 9879–9890 (1999).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  34. 34.

    Yoon, M., Zago, A., Shukla, D. & Spear, P. G. Mutations in the N termini of herpes simplex virus type 1 and 2 gDs alter functional interactions with the entry/fusion receptors HVEM, nectin-2, and 3-O-sulfated heparan sulfate but not with nectin-1. J. Virol. 77, 9221–9231 (2003).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  35. 35.

    Willis, S. H. et al. Examination of the kinetics of herpes simplex virus glycoprotein D binding to the herpesvirus entry mediator, using surface plasmon resonance. J. Virol. 72, 5937–5947 (1998).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  36. 36.

    Krummenacher, C. et al. The first immunoglobulin-like domain of HveC is sufficient to bind herpes simplex virus gD with full affinity, while the third domain is involved in oligomerization of HveC. J. Virol. 73, 8127–8137 (1999).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  37. 37.

    Lazear, E. et al. Engineered disulfide bonds in herpes simplex virus type 1 gD separate receptor binding from fusion initiation and viral entry. J. Virol. 82, 700–709 (2008).

    CAS  PubMed  Article  Google Scholar 

  38. 38.

    Sathiyamoorthy, K. et al. Assembly and architecture of the EBV B cell entry triggering complex. PLoS Pathog. 10, e1004309 (2014). EM reconstructions of the gp42–HLA–gH–gL complex reveal open and closed conformations.

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  39. 39.

    Sorem, J., Jardetzky, T. S. & Longnecker, R. Cleavage and secretion of Epstein-Barr virus glycoprotein 42 promote membrane fusion with B lymphocytes. J. Virol. 83, 6664–6672 (2009).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  40. 40.

    Kirschner, A. N., Lowrey, A. S., Longnecker, R. & Jardetzky, T. S. Binding-site interactions between Epstein-Barr virus fusion proteins gp42 and gH/gL reveal a peptide that inhibits both epithelial and B-cell membrane fusion. J. Virol. 81, 9216–9229 (2007).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  41. 41.

    Silva, A. L., Omerovic, J., Jardetzky, T. S. & Longnecker, R. Mutational analyses of Epstein-Barr virus glycoprotein 42 reveal functional domains not involved in receptor binding but required for membrane fusion. J. Virol. 78, 5946–5956 (2004).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  42. 42.

    Zhou, M., Lanchy, J. M. & Ryckman, B. J. Human cytomegalovirus gH/gL/gO promotes the fusion step of entry into all cell types, whereas gH/gL/UL128–131 broadens virus tropism through a distinct mechanism. J. Virol. 89, 8999–9009 (2015).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  43. 43.

    Wang, D. & Shenk, T. Human cytomegalovirus UL131 open reading frame is required for epithelial cell tropism. J. Virol. 79, 10330–10338 (2005).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  44. 44.

    Zhou, M., Yu, Q., Wechsler, A. & Ryckman, B. J. Comparative analysis of gO isoforms reveals that strains of human cytomegalovirus differ in the ratio of gH/gL/gO and gH/gL/UL128–131 in the virion envelope. J. Virol. 87, 9680–9690 (2013).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  45. 45.

    Wu, Y. et al. Human cytomegalovirus glycoprotein complex gH/gL/gO uses PDGFR-alpha as a key for entry. PLoS Pathog. 13, e1006281 (2017).

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  46. 46.

    E, X. et al. OR14I1 is a receptor for the human cytomegalovirus pentameric complex and defines viral epithelial cell tropism. Proc. Natl Acad. Sci. USA 116, 7043–7052 (2019).

    PubMed  Article  CAS  Google Scholar 

  47. 47.

    Vanarsdall, A. L. et al. CD147 promotes entry of pentamer-expressing human cytomegalovirus into epithelial and endothelial cells. mBio https://doi.org/10.1128/mBio.00781-18 (2018).

    Article  PubMed  PubMed Central  Google Scholar 

  48. 48.

    Liu, J., Jardetzky, T. S., Chin, A. L., Johnson, D. C. & Vanarsdall, A. L. The human cytomegalovirus trimer and pentamer promote sequential steps in entry into epithelial and endothelial cells at cell surfaces and endosomes. J. Virol. https://doi.org/10.1128/JVI.01336-18 (2018).

    Article  PubMed  PubMed Central  Google Scholar 

  49. 49.

    Chen, J. et al. Ephrin receptor A2 is a functional entry receptor for Epstein-Barr virus. Nat. Microbiol. 3, 172–180 (2018).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  50. 50.

    TerBush, A. A., Hafkamp, F., Lee, H. J. & Coscoy, L. A Kaposi’s sarcoma-associated herpesvirus infection mechanism is independent of integrins alpha3beta1, alphaVbeta3, and alphaVbeta5. J. Virol. https://doi.org/10.1128/JVI.00803-18 (2018).

    Article  PubMed  PubMed Central  Google Scholar 

  51. 51.

    Chen, J., Zhang, X., Schaller, S., Jardetzky, T. S. & Longnecker, R. Ephrin receptor A4 is a new Kaposi’s sarcoma-associated herpesvirus virus entry receptor. mBio https://doi.org/10.1128/mBio.02892-18 (2019).

    Article  PubMed  PubMed Central  Google Scholar 

  52. 52.

    Hahn, A. S. et al. The ephrin receptor tyrosine kinase A2 is a cellular receptor for Kaposi’s sarcoma-associated herpesvirus. Nat. Med. 18, 961–966 (2012).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  53. 53.

    Chesnokova, L. S. & Hutt-Fletcher, L. M. Fusion of Epstein-Barr virus with epithelial cells can be triggered by alphavbeta5 in addition to alphavbeta6 and alphavbeta8, and integrin binding triggers a conformational change in glycoproteins gHgL. J. Virol. 85, 13214–13223 (2011).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  54. 54.

    Li, Q., Turk, S. M. & Hutt-Fletcher, L. M. The Epstein-Barr virus (EBV) BZLF2 gene product associates with the gH and gL homologs of EBV and carries an epitope critical to infection of B cells but not of epithelial cells. J. Virol. 69, 3987–3994 (1995).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  55. 55.

    Yang, E., Arvin, A. M. & Oliver, S. L. Role for the alphaV integrin subunit in varicella-zoster virus-mediated fusion and infection. J. Virol. 90, 7567–7578 (2016).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  56. 56.

    Parry, C., Bell, S., Minson, T. & Browne, H. Herpes simplex virus type 1 glycoprotein H binds to alphavbeta3 integrins. J. Gen. Virol. 86, 7–10 (2005).

    CAS  PubMed  Article  Google Scholar 

  57. 57.

    Gianni, T., Salvioli, S., Chesnokova, L. S., Hutt-Fletcher, L. M. & Campadelli-Fiume, G. alphavbeta6- and alphavbeta8-integrins serve as interchangeable receptors for HSV gH/gL to promote endocytosis and activation of membrane fusion. PLoS Pathog. 9, e1003806 (2013).

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  58. 58.

    Chowdary, T. K. et al. Crystal structure of the conserved herpesvirus fusion regulator complex gH-gL. Nat. Strut Mol. Biol. 17, 882–888 (2010). Reports the crystal structure of HSV-2 gH–gL, exhibiting extensive interactions between gL and the N-terminal domain of gH.

    CAS  Article  Google Scholar 

  59. 59.

    Xing, Y. et al. A site of varicella-zoster virus vulnerability identified by structural studies of neutralizing antibodies bound to the glycoprotein complex gHgL. Proc. Natl Acad. Sci. USA 112, 6056–6061 (2015).

    CAS  PubMed  Article  Google Scholar 

  60. 60.

    Backovic, M. et al. Structure of a core fragment of glycoprotein H from pseudorabies virus in complex with antibody. Proc. Natl Acad. Sci. USA 107, 22635–22640 (2010).

    CAS  PubMed  Article  Google Scholar 

  61. 61.

    Matsuura, H., Kirschner, A. N., Longnecker, R. & Jardetzky, T. S. Crystal structure of the Epstein-Barr virus (EBV) glycoprotein H/glycoprotein L (gH/gL) complex. Proc. Natl Acad. Sci. USA 107, 22641–22646 (2010).

    CAS  PubMed  Article  Google Scholar 

  62. 62.

    Connolly, S. A., Jackson, J. O., Jardetzky, T. S. & Longnecker, R. Fusing structure and function: a structural view of the herpesvirus entry machinery. Nat. Rev. Microbiol. 9, 369–381 (2011).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  63. 63.

    Gompels, U. A. et al. Characterization and sequence analyses of antibody-selected antigenic variants of herpes simplex virus show a conformationally complex epitope on glycoprotein H. J. Virol. 65, 2393–2401 (1991).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  64. 64.

    Ciferri, C. et al. Antigenic characterization of the HCMV gH/gL/gO and pentamer cell entry complexes reveals binding sites for potently neutralizing human antibodies. PLoS Pathog. 11, e1005230 (2015).

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  65. 65.

    Sathiyamoorthy, K. et al. Inhibition of EBV-mediated membrane fusion by anti-gHgL antibodies. Proc. Natl Acad. Sci. USA https://doi.org/10.1073/pnas.1704661114 (2017).

    Article  PubMed  Google Scholar 

  66. 66.

    Snijder, J. et al. An antibody targeting the fusion machinery neutralizes dual-tropic infection and defines a site of vulnerability on Epstein-Barr virus. Immunity 48, 799–811 e799 (2018).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  67. 67.

    Wilson, D. W., Davis-Poynter, N. & Minson, A. C. Mutations in the cytoplasmic tail of herpes simplex virus glycoprotein H suppress cell fusion by a syncytial strain. J. Virol. 68, 6985–6993 (1994).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  68. 68.

    Browne, H. M., Bruun, B. C. & Minson, A. C. Characterization of herpes simplex virus type 1 recombinants with mutations in the cytoplasmic tail of glycoprotein H. J. Gen. Virol. 77, 2569–2573 (1996).

    CAS  PubMed  Article  Google Scholar 

  69. 69.

    Jackson, J. O., Lin, E., Spear, P. G. & Longnecker, R. Insertion mutations in herpes simplex virus 1 glycoprotein H reduce cell surface expression, slow the rate of cell fusion, or abrogate functions in cell fusion and viral entry. J. Virol. 84, 2038–2046 (2010).

    CAS  PubMed  Article  Google Scholar 

  70. 70.

    Silverman, J. L. & Heldwein, E. E. Mutations in the cytoplasmic tail of herpes simplex virus 1 gH reduce the fusogenicity of gB in transfected cells. J. Virol. 87, 10139–10147 (2013).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  71. 71.

    Rogalin, H. B. & Heldwein, E. E. Interplay between the herpes simplex virus 1 gB cytodomain and the gH cytotail during cell-cell fusion. J. Virol. 89, 12262–12272 (2015).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  72. 72.

    Yang, E., Arvin, A. M. & Oliver, S. L. The cytoplasmic domain of varicella-zoster virus glycoprotein H regulates syncytia formation and skin pathogenesis. PLoS Pathog. 10, e1004173 (2014).

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  73. 73.

    Vallbracht, M., Fuchs, W., Klupp, B. G. & Mettenleiter, T. C. Functional relevance of the transmembrane domain and cytoplasmic tail of the pseudorabies virus glycoprotein H for membrane fusion. J. Virol. 92, e00376–18 (2018).

    CAS  PubMed  PubMed Central  Google Scholar 

  74. 74.

    Chen, J., Jardetzky, T. S. & Longnecker, R. The cytoplasmic tail domain of Epstein-Barr virus gH regulates membrane fusion activity through altering gH binding to gp42 and epithelial cell attachment. mBio https://doi.org/10.1128/mBio.01871-16 (2016).

    Article  PubMed  PubMed Central  Google Scholar 

  75. 75.

    Rowe, C. L., Connolly, S. A., Chen, J., Jardetzky, T. S. & Longnecker, R. A soluble form of Epstein-Barr virus gH/gL inhibits EBV-induced membrane fusion and does not function in fusion. Virology 436, 118–126 (2013).

    CAS  PubMed  Article  Google Scholar 

  76. 76.

    Jones, N. A. & Geraghty, R. J. Fusion activity of lipid-anchored envelope glycoproteins of herpes simplex virus type 1. Virology 324, 213–228 (2004).

    CAS  PubMed  Article  Google Scholar 

  77. 77.

    Cooper, R. S., Georgieva, E. R., Borbat, P. P., Freed, J. H. & Heldwein, E. E. Structural basis for membrane anchoring and fusion regulation of the herpes simplex virus fusogen gB. Nat. Struct. Mol. Biol. 25, 416–424 (2018). Reports the crystal structure of full-length HSV-1 gB, including the membrane-proximal, transmembrane, and cytoplasmic tail domains.

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  78. 78.

    White, J. M., Delos, S. E., Brecher, M. & Schornberg, K. Structures and mechanisms of viral membrane fusion proteins: multiple variations on a common theme. Crit. Rev. Biochem. Mol. Bio 43, 189–219 (2008).

    CAS  Article  Google Scholar 

  79. 79.

    Heldwein, E. E. et al. Crystal structure of glycoprotein B from herpes simplex virus 1. Science 313, 217–220 (2006).

    CAS  PubMed  Article  Google Scholar 

  80. 80.

    Vallbracht, M. et al. Structure-function dissection of the Pseudorabies virus glycoprotein B fusion loops. J. Virol. 92, e01203–01201 (2017).

    PubMed  PubMed Central  Article  Google Scholar 

  81. 81.

    Li, X. et al. Two classes of protective antibodies against Pseudorabies virus variant glycoprotein B: implications for vaccine design. PLoS Pathog. 13, e1006777 (2017).

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  82. 82.

    Oliver, S. L. et al. A glycoprotein B-neutralizing antibody structure at 2.8 Å uncovers a critical domain for herpesvirus fusion initiation. Nat. Commun. 11, 1–15 (2020).

    Google Scholar 

  83. 83.

    Chandramouli, S. et al. Structure of HCMV glycoprotein B in the postfusion conformation bound to a neutralizing human antibody. Nat. Commun. 6, 8176 (2015). Reports the crystal structure of the postfusion conformation of HCMV gB bound to a nAb.

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  84. 84.

    Burke, H. G. & Heldwein, E. E. Crystal structure of the human cytomegalovirus glycoprotein B. PLoS Pathog. 11, e1005227 (2015). Reports the crystal structure of the postfusion conformation of HCMV gB.

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  85. 85.

    Backovic, M., Longnecker, R. & Jardetzky, T. S. Structure of a trimeric variant of the Epstein-Barr virus glycoprotein B. Proc. Natl Acad. Sci. USA 106, 2880–2885 (2009).

    CAS  PubMed  Article  Google Scholar 

  86. 86.

    Roche, S., Bressanelli, S., Rey, F. A. & Gaudin, Y. Crystal structure of the low-pH form of the vesicular stomatitis virus glycoprotein G. Science 313, 187–191 (2006).

    CAS  PubMed  Article  Google Scholar 

  87. 87.

    Yang, F. et al. Structural analysis of rabies virus glycoprotein reveals pH-dependent conformational changes and interactions with a neutralizing antibody. Cell Host Microbe (2020).

  88. 88.

    Kadlec, J., Loureiro, S., Abrescia, N. G., Stuart, D. I. & Jones, I. M. The postfusion structure of baculovirus gp64 supports a unified view of viral fusion machines. Nat. Struct. Mol. Biol. 15, 1024–1030 (2008).

    CAS  PubMed  Article  Google Scholar 

  89. 89.

    Peng, R. et al. Structures of human-infecting Thogotovirus fusogens support a common ancestor with insect baculovirus. Proc. Natl Acad. Sci. USA 114, E8905–E8912 (2017).

    CAS  PubMed  Article  Google Scholar 

  90. 90.

    Backovic, M. & Jardetzky, T. S. Class III viral membrane fusion proteins. Curr. Opin. Struc Biol. 19, 189–196 (2009).

    CAS  Article  Google Scholar 

  91. 91.

    Bender, F. C. et al. Antigenic and mutational analyses of herpes simplex virus glycoprotein B reveal four functional regions. J. Virol. 81, 3827–3841 (2007).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  92. 92.

    Bootz, A. et al. Protective capacity of neutralizing and non-neutralizing antibodies against glycoprotein B of cytomegalovirus. PLoS Pathog. 13, e1006601 (2017).

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  93. 93.

    Cairns, T. M. et al. Mechanism of neutralization of herpes simplex virus by antibodies directed at the fusion domain of glycoprotein B. J. Virol. 88, 2677–2689 (2014).

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  94. 94.

    Lin, E. & Spear, P. G. Random linker-insertion mutagenesis to identify functional domains of herpes simplex virus type 1 glycoprotein B. Proc. Natl Acad. Sci. USA 104, 13140–13145 (2007).

    CAS  PubMed  Article  Google Scholar 

  95. 95.

    Reimer, J. J., Backovic, M., Deshpande, C. G., Jardetzky, T. & Longnecker, R. Analysis of Epstein-Barr virus glycoprotein B functional domains via linker insertion mutagenesis. J. Virol. 83, 734–747 (2009).

    CAS  PubMed  Article  Google Scholar 

  96. 96.

    Maurer, U. E. et al. The structure of herpesvirus fusion glycoprotein B-bilayer complex reveals the protein-membrane and lateral protein-protein interaction. Structure 21, 1396–1405 (2013).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  97. 97.

    Satoh, T. et al. PILRalpha is a herpes simplex virus-1 entry coreceptor that associates with glycoprotein B. Cell 132, 935–944 (2008).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  98. 98.

    Suenaga, T. et al. Myelin-associated glycoprotein mediates membrane fusion and entry of neurotropic herpesviruses. Proc. Natl Acad. Sci. USA 107, 866–871 (2010).

    CAS  PubMed  Article  Google Scholar 

  99. 99.

    Arii, J. et al. Non-muscle myosin IIA is a functional entry receptor for herpes simplex virus-1. Nature 467, 859–862 (2010).

    CAS  PubMed  Article  Google Scholar 

  100. 100.

    Roche, S., Rey, F. A., Gaudin, Y. & Bressanelli, S. Structure of the prefusion form of the vesicular stomatitis virus glycoprotein G. Science 315, 843–848 (2007).

    CAS  PubMed  Article  Google Scholar 

  101. 101.

    Silverman, J. L., Sharma, S., Cairns, T. M. & Heldwein, E. E. Fusion-deficient insertion mutants of herpes simplex virus 1 glycoprotein B adopt the trimeric postfusion conformation. J. Virol. 84, 2001–2012 (2010).

    CAS  PubMed  Article  Google Scholar 

  102. 102.

    Vitu, E., Sharma, S., Stampfer, S. D. & Heldwein, E. E. Extensive mutagenesis of the HSV-1 gB ectodomain reveals remarkable stability of its postfusion form. J. Mol. Biol. 425, 2056–2071 (2013).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  103. 103.

    Vollmer, B. et al. The pre-fusion structure of herpes simplex virus glycoprotein B. Sci. Adv. 6, eabc1726 (2020). EM reconstructions of a membrane-anchored HSV-1 gB mutant designed to trap the prefusion form reveal a compact structure at an overall resolution of 9 Å.

    PubMed  PubMed Central  Article  Google Scholar 

  104. 104.

    Falanga, A. et al. Biophysical characterization and membrane interaction of the two fusion loops of glycoprotein B from herpes simplex type I virus. PLoS ONE 7, e32186 (2012).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  105. 105.

    Oliver, S. L. et al. Mutagenesis of varicella-zoster virus glycoprotein B: putative fusion loop residues are essential for viral replication, and the furin cleavage motif contributes to pathogenesis in skin tissue in vivo. J. Virol. 83, 7495–7506 (2009).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  106. 106.

    Backovic, M., Jardetzky, T. S. & Longnecker, R. Hydrophobic residues that form putative fusion loops of Epstein-Barr virus glycoprotein B are critical for fusion activity. J. Virol. 81, 9596–9600 (2007).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  107. 107.

    Hannah, B. P. et al. Herpes simplex virus glycoprotein B associates with target membranes via its fusion loops. J. Virol. 83, 6825–6836 (2009).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  108. 108.

    Harrison, S. C. Viral membrane fusion. Virology 479–480, 498–507 (2015).

    PubMed  Article  CAS  Google Scholar 

  109. 109.

    Melikyan, G. B. et al. Evidence that the transition of HIV-1 gp41 into a six-helix bundle, not the bundle configuration, induces membrane fusion. J. Cell Biol. 151, 413–423 (2000).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  110. 110.

    Connolly, S. A. & Longnecker, R. Residues within the C-terminal arm of the herpes simplex virus 1 glycoprotein B ectodomain contribute to its refolding during the fusion step of virus entry. J. Virol. 86, 6386–6393 (2012).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  111. 111.

    Fan, Q., Kopp, S. J., Connolly, S. A. & Longnecker, R. Structure-based mutations in the herpes simplex virus 1 glycoprotein b ectodomain arm impart a slow-entry phenotype. mBio https://doi.org/10.1128/mBio.00614-17 (2017).

    Article  PubMed  PubMed Central  Google Scholar 

  112. 112.

    Waning, D. L., Russell, C. J., Jardetzky, T. S. & Lamb, R. A. Activation of a paramyxovirus fusion protein is modulated by inside-out signaling from the cytoplasmic tail. Proc. Natl Acad. Sci. USA 101, 9217–9222 (2004).

    CAS  PubMed  Article  Google Scholar 

  113. 113.

    Wyss, S. et al. Regulation of human immunodeficiency virus type 1 envelope glycoprotein fusion by a membrane-interactive domain on the gp41 cytoplasmic tail. J. Virol. 79, 12231–12241 (2005).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  114. 114.

    Garcia, N. J., Chen, J. & Longnecker, R. Modulation of Epstein-Barr virus glycoprotein B (gB) fusion activity by the gB cytoplasmic tail domain. mBio 4, e00571–12 (2013).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  115. 115.

    Nixdorf, R., Klupp, B. G., Karger, A. & Mettenleiter, T. C. Effects of truncation of the carboxy terminus of pseudorabies virus glycoprotein B on infectivity. J. Virol. 74, 7137–7145 (2000).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  116. 116.

    Fan, Z. et al. Truncation of herpes simplex virus type 2 glycoprotein B increases its cell surface expression and activity in cell-cell fusion, but these properties are unrelated. J. Virol. 76, 9271–9283 (2002).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  117. 117.

    Muggeridge, M. I., Grantham, M. L. & Johnson, F. B. Identification of syncytial mutations in a clinical isolate of herpes simplex virus 2. Virology 328, 244–253 (2004).

    CAS  PubMed  Article  Google Scholar 

  118. 118.

    Silverman, J. L., Greene, N. G., King, D. S. & Heldwein, E. E. Membrane requirement for folding of the herpes simplex virus 1 gB cytodomain suggests a unique mechanism of fusion regulation. J. Virol. 86, 8171–8184 (2012).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  119. 119.

    Oliver, S. L. et al. An immunoreceptor tyrosine-based inhibition motif in varicella-zoster virus glycoprotein B regulates cell fusion and skin pathogenesis. Proc. Natl Acad. Sci. USA 110, 1911–1916 (2013).

    CAS  PubMed  Article  Google Scholar 

  120. 120.

    Cooper, R. S. & Heldwein, E. E. Herpesvirus gB: a finely tuned fusion machine. Viruses 7, 6552–6569 (2015).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  121. 121.

    Gallagher, J. R. et al. Functional fluorescent protein insertions in herpes simplex virus gB report on gB conformation before and after execution of membrane fusion. PLoS Pathog. 10, e1004373 (2014).

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  122. 122.

    Zeev-Ben-Mordehai, T. et al. Two distinct trimeric conformations of natively membrane-anchored full-length herpes simplex virus 1 glycoprotein B. Proc. Natl Acad. Sci. USA 113, 4176–4181 (2016).

    CAS  PubMed  Article  Google Scholar 

  123. 123.

    Fontana, J. et al. The fusion loops of the initial prefusion conformation of herpes simplex virus 1 fusion protein point toward the membrane. mBio https://doi.org/10.1128/mBio.01268-17 (2017).

    Article  PubMed  PubMed Central  Google Scholar 

  124. 124.

    Si, Z. et al. Different functional states of fusion protein gB revealed on human cytomegalovirus by cryo electron tomography with Volta phase plate. PLoS Pathog. 14, e1007452 (2018).

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  125. 125.

    Handler, C. G., Cohen, G. H. & Eisenberg, R. J. Cross-linking of glycoprotein oligomers during herpes simplex virus type 1 entry. J. Virol. 70, 6076–6082 (1996).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  126. 126.

    Gianni, T., Amasio, M. & Campadelli-Fiume, G. Herpes simplex virus gD forms distinct complexes with fusion executors gB and gH/gL in part through the C-terminal profusion domain. J. Biol. Chem. 284, 17370–17382 (2009).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  127. 127.

    Perez-Romero, P., Perez, A., Capul, A., Montgomery, R. & Fuller, A. O. Herpes simplex virus entry mediator associates in infected cells in a complex with viral proteins gD and at least gH. J. Virol. 79, 4540–4544 (2005).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  128. 128.

    Avitabile, E., Forghieri, C. & Campadelli-Fiume, G. Complexes between herpes simplex virus glycoproteins gD, gB, and gH detected in cells by complementation of split enhanced green fluorescent protein. J. Virol. 81, 11532–11537 (2007).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  129. 129.

    Atanasiu, D. et al. Bimolecular complementation reveals that glycoproteins gB and gH/gL of herpes simplex virus interact with each other during cell fusion. Proc. Natl Acad. Sci. USA 104, 18718–18723 (2007).

    CAS  PubMed  Article  Google Scholar 

  130. 130.

    Fan, Q., Longnecker, R. & Connolly, S. A. Substitution of herpes simplex virus 1 entry glycoproteins with those of saimiriine herpesvirus 1 reveals a gD-gH/gL functional interaction and a region within the gD profusion domain that is critical for fusion. J. Virol. 88, 6470–6482 (2014).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  131. 131.

    Fan, Q., Longnecker, R. & Connolly, S. A. A functional interaction between herpes simplex virus 1 glycoprotein gH/gL domains I and II and gD is defined by using alphaherpesvirus gH and gL chimeras. J. Virol. 89, 7159–7169 (2015).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  132. 132.

    Atanasiu, D. et al. Regulation of herpes simplex virus gB-induced cell-cell fusion by mutant forms of gH/gL in the absence of gD and cellular receptors. mBio https://doi.org/10.1128/mBio.00046-13 (2013).

    Article  PubMed  PubMed Central  Google Scholar 

  133. 133.

    Cairns, T. M. et al. Surface plasmon resonance reveals direct binding of herpes simplex virus glycoproteins gH/gL to gD and Locates a gH/gL binding site on gD. J. Virol. https://doi.org/10.1128/JVI.00289-19 (2019). Demonstrates direct interaction between purified forms of the HSV-2 gD and gH–gL ectodomains.

    Article  PubMed  PubMed Central  Google Scholar 

  134. 134.

    Atanasiu, D. et al. Bimolecular complementation defines functional regions of Herpes simplex virus gB that are involved with gH/gL as a necessary step leading to cell fusion. J. Virol. 84, 3825–3834 (2010).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  135. 135.

    Vanarsdall, A. L., Ryckman, B. J., Chase, M. C. & Johnson, D. C. Human cytomegalovirus glycoproteins gB and gH/gL mediate epithelial cell-cell fusion when expressed in cis or in trans. J. Virol. 82, 11837–11850 (2008).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  136. 136.

    Oxman, M. N. et al. A vaccine to prevent herpes zoster and postherpetic neuralgia in older adults. N. Engl. J. Med. 352, 2271–2284 (2005).

    CAS  PubMed  Article  Google Scholar 

  137. 137.

    Cunningham, A. L. et al. Efficacy of the herpes zoster subunit vaccine in adults 70 years of age or older. N. Engl. J. Med. 375, 1019–1032 (2016).

    CAS  PubMed  Article  Google Scholar 

Download references

Acknowledgements

This work was supported by grants AI-137267 and AI-148478 from the US National Institute of Allergy and Infectious Diseases of the National Institutes of Health. All crystal structures in this Review were rendered with MacPyMOL.

Author information

Affiliations

Authors

Contributions

The authors contributed equally to all aspects of the article.

Corresponding authors

Correspondence to Sarah A. Connolly or Richard Longnecker.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information

Nature Reviews Microbiology thanks A. Carfi, K. Grünewald, A. Nicola, L. Perez, B. Vollmer and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Related links

EMDataResource: http://www.emdataresource.org/

RCSB Protein Data Bank: https://www.rcsb.org/

Glossary

Enveloped viruses

Viruses with an outer layer consisting of a lipid bilayer, in which the viral glycoproteins responsible for mediating virus entry into cells are embedded.

Conformational changes

Changes in protein structure made possible by the intrinsic flexibility of the protein that can be triggered by environmental factors, such as binding to a receptor or another glycoprotein.

Entry receptors

Molecules present in host cells that bind directly to viruses and mediate virus entry into the cell.

Cell tropism

The specific cell types that support the replication of different viruses.

Crystal structures

Structural models based on X-ray diffraction of a crystal that often permit atomic resolution for protein structures.

Neutralizing monoclonal antibodies

(nAbs). Antibodies that bind to a virus particle and prevent infection, typically by preventing virus entry into the cell.

Fusion loops

Short stretches of hydrophobic residues within a fusion protein that insert themselves into the host cell membrane during the fusion event.

Cryo-electron tomography

(cryo-ET). Method to produce high-resolution 3D models of molecules held at cryogenic temperature by reconstructing a series of 2D electron microscopy images taken from multiple angles.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Connolly, S.A., Jardetzky, T.S. & Longnecker, R. The structural basis of herpesvirus entry. Nat Rev Microbiol (2020). https://doi.org/10.1038/s41579-020-00448-w

Download citation

Search

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing