Two Key Residues in EphrinB3 Are Critical for Its Use as an Alternative Receptor for Nipah Virus

PLoS Pathogens

Wei Wang¹  Benhur Lee²  Stephen V Su²  Hector C Aguilar²  Oscar A Negrete²  Mike C Wolf²  Andrea Bertolotti-Ciarlet³  Elke Mühlberger⁴  Ramon Flick⁵  Sven Enterlein⁵ 

[1] Department of Medicine-Infectious Diseases, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America;Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America;Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America;Institute for Virology, Philipps-University Marburg, Marburg, Germany;University of Texas Medical Branch, Galveston, Texas, United States of America

关键词: Cell binding;    CHO cells;    Endothelial cells;    Viral entry;    Spinal cord;    Vesicular stomatitis virus;    Neurons;    Nipah virus;   

DOI  :  10.1371/journal.ppat.0020007

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

EphrinB2 was recently discovered as a functional receptor for Nipah virus (NiV), a lethal emerging paramyxovirus. Ephrins constitute a class of homologous ligands for the Eph class of receptor tyrosine kinases and exhibit overlapping expression patterns. Thus, we examined whether other ephrins might serve as alternative receptors for NiV. Here, we show that of all known ephrins (ephrinA1–A5 and ephrinB1–B3), only the soluble Fc-fusion proteins of ephrinB3, in addition to ephrinB2, bound to soluble NiV attachment protein G (NiV-G). Soluble NiV-G bound to cell surface ephrinB3 and B2 with subnanomolar affinities (Kd = 0.58 nM and 0.06 nM for ephrinB3 and B2, respectively). Surface plasmon resonance analysis indicated that the relatively lower affinity of NiV-G for ephrinB3 was largely due to a faster off-rate (Koff = 1.94 × 10−3 s−1 versus 1.06 × 10−4 s−1 for ephrinB3 and B2, respectively). EphrinB3 was sufficient to allow for viral entry of both pseudotype and live NiV. Soluble ephrinB2 and B3 were able to compete for NiV-envelope-mediated viral entry on both ephrinB2- and B3-expressing cells, suggesting that NiV-G interacts with both ephrinB2 and B3 via an overlapping site. Mutational analysis indicated that the Leu–Trp residues in the solvent exposed G–H loop of ephrinB2 and B3 were critical determinants of NiV binding and entry. Indeed, replacement of the Tyr–Met residues in the homologous positions in ephrinB1 with Leu–Trp conferred NiV receptor activity to ephrinB1. Thus, ephrinB3 is a bona fide alternate receptor for NiV entry, and two residues in the G–H loop of the ephrin B-class ligands are critical determinants of NiV receptor activity.

【 授权许可】

CC BY