Amino acid residues 68-71 contribute to influenza A virus PB1-F2 protein stability and functions

Yi Ying Cheng, Shih Rang Yang, Ying Ting Wang, Yu Hsin Lin, Chi Ju Chen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Influenza A virus PB1-F2, encoding a multi-functional protein, is regarded as a virulent gene. Variation in expression pattern and protein stability among PB1-F2 proteins derived from different strains may explain why PB1-F2 functions in a strain- and cell type-specific manner. Because the protein stability of PB1-F2 affects its biological functions, we looked for sequences important for this property. By comparing variants and chimeric of PB1-F2 proteins from A/Hong Kong/156/1997 (H5N1) and A/Puerto Rico/8/1934 (H1N1), we identified amino acid residues 68-71 affect its protein stability. PB1-F2 with T68, Q69, D70, and S71 has a shorter protein half-life than its I68, L69, V70, and F71 counterpart. This is likely to do with proteasome-mediated degradation. Swapping amino acids 68-71 between two proteins reversed not only the length of protein half-life and sensitivity to MG132, but also subcellular localization and interferon antagonization. Our data suggested that composition of amino acids 68-71, which regulates protein stability and therefore its functions, can be a major factor determining strain-specificity of PB1-F2.

Original languageEnglish
Article number692
JournalFrontiers in Microbiology
Issue numberAPR
StatePublished - 21 Apr 2017


  • Influenza A virus
  • Interferon antagonism
  • Mitochondrial localization
  • PB1-F2
  • Protein stability


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