A conserved basic loop in hepatitis C virus p7 protein is required for amantadine-sensitive ion channel activity in mammalian cells but is dispensable for localization to mitochondria.
We previously identified the function of the hepatitis C virus (HCV) p7 protein as an ion channel in artificial lipid bilayers and demonstrated that this in vitro activity is inhibited by amantadine. Here we show that the ion channel activity of HCV p7 expressed in mammalian cells can substitute for that of influenza virus M2 in a cell-based assay. This was also the case for the p7 from the related virus, bovine viral diarrhoea virus (BVDV). Moreover, amantadine was shown to abrogate HCV p7 function in this assay at a concentration that specifically inhibits M2. Mutation of a conserved basic loop located between the two predicted trans-membrane alpha helices rendered HCV p7 non-functional as an ion channel. The intracellular localization of p7 was unaffected by this mutation and was found to overlap significantly with membranes associated with mitochondria. Demonstration of p7 ion channel activity in cellular membranes and its inhibition by amantadine affirm the protein as a target for future anti-viral chemotherapy.
Griffin
Stephen D C
SDC
Astbury Centre of Molecular Biology, School of Biochemistry and Microbiology, University of Leeds, Leeds LS2 9JT, UK.
Harvey
Ruth
R
Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
Clarke
Dean S
DS
Astbury Centre of Molecular Biology, School of Biochemistry and Microbiology, University of Leeds, Leeds LS2 9JT, UK.
Barclay
Wendy S
WS
School of Animal and Microbial Sciences, University of Reading, Whiteknights, PO Box 228, Reading, Berkshire RG6 6AJ, UK.
Harris
Mark
M
Astbury Centre of Molecular Biology, School of Biochemistry and Microbiology, University of Leeds, Leeds LS2 9JT, UK.
Rowlands
David J
DJ
Astbury Centre of Molecular Biology, School of Biochemistry and Microbiology, University of Leeds, Leeds LS2 9JT, UK.
D000547:Amantadine / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology; D002460:Cell Line; D016174:Hepacivirus / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007473:Ion Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008322:Mammals; D008928:Mitochondria / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D014763:Viral Matrix Proteins / Q000378:metabolism; D014764:Viral Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000086082:Viroporin Proteins
D000547:Amantadine; D000998:Antiviral Agents; D007473:Ion Channels; D014763:Viral Matrix Proteins; D014764:Viral Proteins; C031540:M-protein, influenza virus; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins; C088369:p7 protein, Hepatitis C virus