Interaction of Nuclear Export Protein with G Protein Pathway Suppressor 2 (GPS2) Facilitates Influenza A Virus Replication by Weakening the Inhibition of GPS2 to RNA Synthesis and Ribonucleoprotein Assembly

Wenxiao Gong,Meilin Jin,Yufei Zhang,Xinglin He,Kun Huang,Zhong Zou,Ying Yang,Chengfei Li,Bryan R.G. Williams

doi:10.1128/jvi.00008-21

Wenxiao Gong, Meilin Jin + Show 7 more

Open Access

https://doi.org/10.1128/jvi.00008-21

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Journal: Journal of Virology	Publication Date: Apr 26, 2021
Citations: 6	License type: CC BY 4.0

Affiliation: Huazhong Agricultural University

Abstract

The nuclear export protein (NEP) serves multiple functions in the life cycle of influenza A virus (IAV). Identifying novel host proteins that interact with NEP and understanding their functions in IAV replication are of great interest. In this study, we screened and confirmed the direct interaction of G protein pathway suppressor 2 (GPS2) with NEP through a yeast two-hybrid screening assay and glutathione S-transferase-pulldown and co-immunoprecipitation assays. Knockdown or knockout of GPS2 enhanced IAV titers, whereas overexpression of GPS2 impaired IAV replication, demonstrating that GPS2 acted as a negative host factor in IAV replication. Meanwhile, GPS2 inhibited viral RNA synthesis by reducing the assembly of IAV polymerase. Interestingly, IAV NEP interacted with GPS2 and mediated its nuclear export, thereby activated the degradation of GPS2. Thus, NEP-GPS2 interaction weakened the inhibition of GPS2 to viral polymerase activity and benefited virus replication. Overall, this study identified the novel NEP-binding host partner GPS2 as a critical host factor to participate in IAV replication. These findings provided novel insights into the interactions between IAV and host cells, revealing a new function for GPS2 during IAV replication.Importance: NEP is proposed to play multiple biologically important roles in the life cycle of IAV, which largely relies on host factors by interaction. Our study demonstrated that GPS2 could reduce the interaction between PB1 and PB2 and interfere with vRNP assembly. Thus, GPS2 inhibited the RNA synthesis of IAV and negatively regulated its replication. Importantly, IAV NEP interacted with GPS2 and mediated the nuclear export of GPS2, thereby activated the degradation of GPS2. Thus, NEP-GPS2 interaction weakened the inhibition of GPS2 to viral polymerase activity and benefited virus replication.

Highlights

The nuclear export protein (NEP) serves multiple functions in the life cycle of influenza A virus (IAV)
We demonstrated that NEP-G protein pathway suppressor 2 (GPS2) interaction was a positive regulator of IAV by mediating the nuclear export of GPS2 and promoting the degradation of GPS2 to alleviate the inhibition to polymerase activity and viral ribonucleoprotein (vRNP) assembly
During the life cycle of IAV, new synthetic viral proteins such as PB2, NP, and polymerase basic 1 (PB1)-PA heterodimers are transported into the nucleus to form new viral RNA-dependent RNA polymerase (RdRp) [45]

Summary

Introduction

The nuclear export protein (NEP) serves multiple functions in the life cycle of influenza A virus (IAV). Identifying novel host proteins that interact with NEP and understanding their functions in IAV replication are of great interest. This study identified the novel NEP-binding host partner GPS2 as a critical host factor to participate in IAV replication. IMPORTANCE NEP is proposed to play multiple biologically important roles in the life cycle of IAV, which largely relies on host factors by interaction. The nuclear export protein (NEP) is derived from alternatively spliced RNAs that are transcribed from RNA segment 8 of the viral genome [10] and is proposed to play multiple biologically important roles during the life cycle of IAV [11].

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