Epitopes described in "A novel receptor-induced activation site in the Nipah virus attachment glycoprotein (G) involved in triggering the fusion glycoprotein (F)."

Article Authors:Hector C Aguilar; Zeynep Akyol Ataman; Vanessa Aspericueta; Angela Q Fang; Matthew Stroud; Oscar A Negrete; Richard A Kammerer; Benhur Lee
Article Title:A novel receptor-induced activation site in the Nipah virus attachment glycoprotein (G) involved in triggering the fusion glycoprotein (F).
Reference Detail
Reference ID:1014020
Abstract:Cellular entry of paramyxoviruses requires the coordinated action of both the attachment (G/H/HN) and fusion (F) glycoproteins, but how receptor binding activates G to trigger F-mediated fusion during viral entry is not known. Here, we identify a receptor (ephrinB2)-induced allosteric activation site in Nipah virus (NiV) G involved in triggering F-mediated fusion. We first generated a conformational monoclonal antibody (monoclonal antibody 45 (Mab45)) whose binding to NiV-G was enhanced upon NiV-G-ephrinB2 binding. However, Mab45 also inhibited viral entry, and its receptor binding-enhanced (RBE) epitope was temperature-dependent, suggesting that the Mab45 RBE epitope on G may be involved in triggering F. The Mab45 RBE epitope was mapped to the base of the globular domain (beta6S4/beta1H1). Alanine scan mutants within this region that did not exhibit this RBE epitope were also non-fusogenic despite their ability to bind ephrinB2, oligomerize, and associate with F at wild-type (WT) levels. Although circular dichroism revealed conformational changes in the soluble ectodomain of WT NiV-G upon ephrinB2 addition, no such changes were detected with soluble RBE epitope mutants or short-stalk G mutants. Additionally, WT G, but not a RBE epitope mutant, could dissociate from F upon ephrinB2 engagement. Finally, using a biotinylated HR2 peptide to detect pre-hairpin intermediate formation, a cardinal feature of F-triggering, we showed that ephrinB2 binding to WT G, but not the RBE-epitope mutants, could trigger F. In sum, we implicate the coordinated interaction between the base of NiV-G globular head domain and the stalk domain in mediating receptor-induced F triggering during viral entry.
Affiliations:Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA. haguilar@ucla.edu.
Reference Type:Literature
PubMed ID:19019819
Journal:J Biol Chem
Journal Volume:284
Article Pages:1628-35
Journal ISSN:0021-9258
Article Chemical List:Antibodies, Monoclonal;Ephrin-B2;Epitopes;F protein, Nipah virus;Viral Envelope Proteins
Article MeSH List:Animals; Antibodies, Monoclonal(pharmacology); CHO Cells; Cercopithecus aethiops; Cricetinae; Cricetulus; Ephrin-B2(genetics; metabolism); Epitopes(metabolism); Humans; Mutation; Nipah Virus(genetics; metabolism); Peptide Mapping(methods); Protein Structure, Tertiary(physiology); Vero Cells; Viral Envelope Proteins(antagonists & inhibitors; genetics; metabolism); Virus Internalization(drug effects)
Curation Last Updated:2015-06-05 01:33:12