Mumps Virus SH Protein Inhibits NF-kappaB Activation by Interacting with Tumor Necrosis Factor Receptor 1, Interleukin-1 Receptor 1, and Toll-Like Receptor 3 Complexes.
Article Details
- CitationCopy to clipboard
Franz S, Rennert P, Woznik M, Grutzke J, Ludde A, Arriero Pais EM, Finsterbusch T, Geyer H, Mankertz A, Friedrich N
Mumps Virus SH Protein Inhibits NF-kappaB Activation by Interacting with Tumor Necrosis Factor Receptor 1, Interleukin-1 Receptor 1, and Toll-Like Receptor 3 Complexes.
J Virol. 2017 Aug 24;91(18). pii: JVI.01037-17. doi: 10.1128/JVI.01037-17. Print 2017 Sep 15.
- PubMed ID
- 28659487 [ View in PubMed]
- Abstract
The mumps virus (MuV) small hydrophobic protein (SH) is a type I membrane protein expressed in infected cells. SH has been reported to interfere with innate immunity by inhibiting tumor necrosis factor alpha (TNF-alpha)-mediated apoptosis and NF-kappaB activation. To elucidate the underlying mechanism, we generated recombinant MuVs (rMuVs) expressing the SH protein with an N-terminal FLAG epitope or lacking SH expression due to the insertion of three stop codons into the SH gene. Using these viruses, we were able to show that SH reduces the phosphorylation of IKKbeta, IkappaBalpha, and p65 as well as the translocation of p65 into the nucleus of infected A549 cells. Reporter gene assays revealed that SH interferes not only with TNF-alpha-mediated NF-kappaB activation but also with IL-1beta- and poly(I.C)-mediated NF-kappaB activation, and that this inhibition occurs upstream of the NF-kappaB pathway components TRAF2, TRAF6, and TAK1. Since SH coimmunoprecipitated with tumor necrosis factor receptor 1 (TNFR1), RIP1, and IRAK1, we hypothesize that SH exerts its inhibitory function by interacting with TNFR1, interleukin-1 receptor type 1 (IL-1R1), and TLR3 complexes in the plasma membrane of infected cells.IMPORTANCE The MuV SH has been shown to impede TNF-alpha-mediated NF-kappaB activation and is therefore thought to contribute to viral immune evasion. However, the mechanisms by which SH mediates NF-kappaB inhibition remained largely unknown. In this study, we show that SH interacts with TNFR1, IL-1R1, and TLR3 complexes in infected cells. We thereby not only shed light on the mechanisms of SH-mediated NF-kappaB inhibition but also reveal that SH interferes with NF-kappaB activation induced by interleukin-1beta (IL-1beta) and double-stranded RNA.