pH modulating activity of ion channels of influenza A, B, and C viruses.
The BM2 and NB proteins of Influenza B virus (the B virus) and the CM2 protein of Influenza C virus (the C virus) are structural homologs of the M2 protein of Influenza A virus (the A virus). It was shown recently that CM2 in vitro forms a voltage-activated ion channel permeable to chloride ion (Hongo et al., Arch. Virol. 149, 35-50, 2004). To demonstrate a possible pH modulating activity of BM2, NB and CM2, the latters were co-expressed with a pH-sensitive hemagglutinin (HA) of the A virus. BM2 was able to replace functionally M2 and prevented the A virus HA from adopting its low-pH conformation during transport to the cell surface. In contrast, NB had a negative effect on the quality of the co-expressed HA and was unable to modulate the pH in the trans-Golgi network (TGN) and to protect HA. A pH modulating activity was also demonstrated for CM2, but it was much lower than that of M2.
Betáková
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Institute of Virology, Slovak Academy of Sciences, Dúbravská cesta 9, 845 05 Bratislava, Slovak Republic. virubeta@savba.sk
Kollerová
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D000818:Animals; D002460:Cell Line; D015967:Gene Expression Regulation, Viral; D006367:HeLa Cells; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009980:Influenza A virus / Q000378:metabolism*; D009981:Influenza B virus / Q000378:metabolism*; D009982:Gammainfluenzavirus / Q000378:metabolism*; D007473:Ion Channels / Q000378:metabolism / Q000502:physiology*; D014763:Viral Matrix Proteins / Q000378:metabolism; D014764:Viral Proteins / Q000378:metabolism; D000086082:Viroporin Proteins
D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007473:Ion Channels; D014763:Viral Matrix Proteins; D014764:Viral Proteins; C064964:BM2 polypeptide, influenza B virus; C090877:CM2 protein, Influenza C virus; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins; C051094:NB glycoprotein, Influenza B virus