Identification of Glucose-Regulated Protein 78 (GRP78) as a Receptor in BHK-21 Cells for Duck Tembusu Virus Infection.

Dongmin Zhao,Qingtao Liu,Keran Bi,Kaikai Han,Na Liu,Jing Yang,Huili Wang,Yin Li,Yuzhuo Liu,Yujie Tian

doi:10.3389/fmicb.2018.00694

Dongmin Zhao, Qingtao Liu + Show 8 more

Open Access

https://doi.org/10.3389/fmicb.2018.00694

Copy DOI

Abstract

Since 2010, outbreak and spread of tembusu virus (TMUV) caused huge losses to the breeding industry of waterfowl in several provinces of China. In this study, we identify the glucose-regulated protein 78 (GRP78) as a receptor in BHK-21 cells for duck TMUV infection. Using cell membrane from BHK-21 cells, a TMUV-binding protein of approximately 70 kDa was observed by viral overlay protein binding assay (VOPBA). LC-MS/MS analysis and co-immunoprecipitation identified GRP78 as a protein interacting with TMUV. Antibody against GRP78 inhibited the binding of TMUV to the cell surface of BHK-21 cells. Indirect immunofluorescence studies showed the colocalization of GRP78 with TMUV in virus-infected BHK-21 cells. We found that GRP78 over-expression increased TMUV infection, whereas GRP78 knockdown by using a specific small interfering RNA inhibited TMUV infection in BHK-21 cells. Taken together, our results indicate that GRP78 is a novel host factor involved in TMUV entry.

Highlights

Tembusu virus (TMUV) caused severe disease in ducks and spread rapidly in many duckproducing provinces of China since 2010
Viral overlay protein binding assay was used to preliminarily identify the molecules in BHK-21 cells involved in tembusu virus (TMUV) binding
glucose-regulated protein 78 (GRP78) has been traditionally regarded as endoplasmic reticulum lumenal protein, many studies provide the evidence that GRP78 can be detected on cell surface and exerts functions beyond the endoplasmic reticulum (Tsai et al, 2015)

Summary

Introduction

Tembusu virus (TMUV) caused severe disease in ducks and spread rapidly in many duckproducing provinces of China since 2010. Family Flaviviridae, genus Flavivirus, is made up of three structural proteins (envelope [E], capsid [C], and membrane [M]) and seven non-structural proteins (NS1, NS2a, NS2b, NS3, NS4a, NS4b, and NS5). Among these viral proteins, E protein is the main structural protein, which has three separate domains and form head-to-tail homodimers on the surface of the virion (Oliphant et al, 2006).

Methods

Results

Conclusion