Machupo virus glycoprotein determinants for human transferrin receptor 1 binding and cell entry.

Sheli R Radoshitzky,Lian Dong,Jeremiah C Clester,Lindsay E Longobardi,John Carra,Jens H Kuhn,Cary Retterer,Sina Bavari,Krishna Kota

doi:10.1371/journal.pone.0021398

Abstract

Machupo virus (MACV) is a highly pathogenic New World arenavirus that causes hemorrhagic fever in humans. MACV, as well as other pathogenic New World arenaviruses, enter cells after their GP1 attachment glycoprotein binds to their cellular receptor, transferrin receptor 1 (TfR1). TfR1 residues essential for this interaction have been described, and a co-crystal of MACV GP1 bound to TfR1 suggests GP1 residues important for this association. We created MACV GP1 variants and tested their effect on TfR1 binding and virus entry to evaluate the functional significance of some of these and additional residues in human and simian cells. We found residues R111, D123, Y122, and F226 to be essential, D155, and P160 important, and D114, S116, D140, and K169 expendable for the GP1-TfR1 interaction and MACV entry. Several MACV GP1 residues that are critical for the interaction with TfR1 are conserved among other New World arenaviruses, indicating a common basis of receptor interaction. Our findings also open avenues for the rational development of viral entry inhibitors.

Highlights

Arenaviruses have single-stranded, bisegmented ambisense RNA genomes and form enveloped virions [1]
We followed a strategy previously employed for virus receptor identification to evaluate the importance for transferrin receptor 1 (TfR1) binding of these conserved residues, as well as GP1 residues recently indicated in the published Machupo virus (MACV) GP1:TfR1 crystal structure [17,26]
Our results demonstrate that GP1 residues R111, D123, Y122, and F226 are important for human TfR1 (hTfR1) binding and cellentry of MACV (Figs. 2 and 3)

Summary

Introduction

Arenaviruses have single-stranded, bisegmented ambisense RNA genomes and form enveloped virions [1]. Exceptions were Y122, S116A and D114A/S116A (motif 2), which bound the cell-surface of Vero cells as or almost as efficiently as wt MACV GP1D, yet exhibited lower hTfR1 levels in the co-IP assays. The K167A mutant exhibited an opposite trend, as it bound less efficiently to the cell-surface than wt MACV GP1D whereas it immunoprecipitated hTfR1 as effectively.

Results

Conclusion