NF90 is a novel influenza A virus NS1‐interacting protein that antagonizes the inhibitory role of NS1 on PKR phosphorylation

• Published in: FEBS letters 2016-08, Vol.590 (16), p.2797-2810
• Main Authors: Li, Ting, Li, Xi, Zhu, WenFei, Wang, HuiYu, Mei, Lin, Wu, ShaoQiang, Lin, XiangMei, Han, XueQing
• Format: Article
• Language: English
• Subjects: eIF-2 Kinase - chemistry; eIF-2 Kinase - metabolism; HEK293 Cells - virology; Humans; influenza A virus; Influenza A virus - genetics; Influenza A virus - metabolism; Influenza A virus - pathogenicity; Influenza, Human - genetics; Influenza, Human - metabolism; Influenza, Human - virology; NF90; nonstructural protein 1; Nuclear Factor 90 Proteins - genetics; Nuclear Factor 90 Proteins - metabolism; Phosphorylation - genetics; protein kinase R phosphorylation; RNA-Binding Proteins - chemistry; RNA-Binding Proteins - metabolism; stress granules; Viral Nonstructural Proteins - chemistry; Viral Nonstructural Proteins - metabolism; Virus Replication - genetics
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1002/1873-3468.12311

NF90 is a novel host antiviral factor that regulates PKR activation and stress granule formation in influenza A virus (IAV)‐infected cells, but the precise mechanisms by which it operates remain unclear. We identified NF90 as a novel interacting protein of IAV nonstructural protein 1 (NS1). The interaction was dependent on the RNA‐binding properties of NS1. NS1 associated with NF90 and PKR simultaneously; however, the interaction between NF90 and PKR was restricted by NS1. Knockdown of NF90 promoted inhibition of PKR phosphorylation induced by NS1, while coexpression of NF90 impeded reduction of PKR phosphorylation and stress granule formation triggered by NS1. In summary, NF90 exerts its antiviral activity by antagonizing the inhibitory role of NS1 on PKR phosphorylation.