Abstract
The M2 proteins of influenza A and B virus, AM2 and BM2, respectively, are transmembrane proteins that oligomerize in the viral membrane to form proton-selective channels. Proton conductance of the M2 proteins is required for viral replication; it is believed to equilibrate pH across the viral membrane during cell entry and across the trans-Golgi membrane of infected cells during viral maturation. In addition to the role of M2 in proton conductance, recent mutagenesis and structural studies suggest that the cytoplasmic domains of the M2 proteins also play a role in recruiting the matrix proteins to the cell surface during virus budding. As viral ion channels of minimalist architecture, the membrane-embedded channel domain of M2 has been a model system for investigating the mechanism of proton conduction. Moreover, as a proven drug target for the treatment of influenza A infection, M2 has been the subject of intense research for developing new anti-flu therapeutics. AM2 is the target of two anti-influenza A drugs, amantadine and rimantadine, both belonging to the adamantane class of compounds. However, resistance of influenza A to adamantane is now widespread due to mutations in the channel domain of AM2. This review summarizes the structure and function of both AM2 and BM2 channels, the mechanism of drug inhibition and drug resistance of AM2, as well as the development of new M2 inhibitors as potential anti-flu drugs.
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Aldrich, P.E., Hermann, E.C., Meier, W.E., Paulshock, M., Prichard, W.W., Snyder, J.A., and Watts, J.C. (1971). Antiviral agents. 2. Structure-activity relationships of compounds related to 1-adamantanamine. J Med Chem 14, 535–543.
Ali, A., Avalos, R.T., Ponimaskin, E., and Nayak, D.P. (2000). Influenza virus assembly: effect of influenza virus glycoproteins on the membrane association of M1 protein. J Virol 74, 8709–8719.
Bright, R.A., Shay, D.K., Shu, B., Cox, N.J., and Klimov, A.I. (2006). Adamantane resistance among influenza A viruses isolated early during the 2005-2006 influenza season in the United States. Jama 295, 891–894.
Cady, S.D., Mishanina, T.V., and Hong, M. (2009). Structure of amantadine-bound M2 transmembrane peptide of influenza A in lipid bilayers from magic-angle-spinning solid-state NMR: the role of Ser31 in amantadine binding. J Mol Biol 385, 1127–1141.
Chen, B.J., Leser, G.P., Jackson, D., and Lamb, R.A. (2008). The influenza virus M2 protein cytoplasmic tail interacts with the M1 protein and influences virus assembly at the site of virus budding. J Virol 82, 10059–10070.
Davies, W.L., Grunert, R.R., Haff, R.F., McGahen, J.W., Neumayer, E. M., Paulshock, M., Watts, J.C., Wood, T.R., Hermann, E.C., and Hoffmann, C.E. (1964). Antiviral Activity of 1-Adamantanamine (Amantadine). Science 144, 862–863.
Du, Q.S., Huang, R.B., Wang, C.H., Li, X.M., and Chou, K.C. (2009). Energetic analysis of the two controversial drug binding sites of the M2 proton channel in influenza A virus. J Theor Biol 259, 159–164.
Duff, K.C., Gilchrist, P.J., Saxena, A.M., and Bradshaw, J.P. (1994). Neutron diffraction reveals the site of amantadine blockade in the influenza A M2 ion channel. Virology 202, 287–293.
Felder, C., Prilusky, J., Silman, I., and Sussman, J. (2007). A server and database for dipole moments of proteins. Nucleic Acids Research 35, special Web Servers Issue.
Gandhi, C.S., Shuck, K., Lear, J.D., Dieckmann, G.R., DeGrado, W. F., Lamb, R.A., and Pinto, L.H. (1999). Cu(II) inhibition of the proton translocation machinery of the influenza A virus M2 protein. J Biol Chem 274, 5474–5482.
Harbury, P.B., Zhang, T., Kim, P.S., and Alber, T. (1993). A switch between two-, three-, and four-stranded coiled coils in GCN4 leucine zipper mutants. Science 262, 1401–1407.
Hay, A.J., Wolstenholme, A.J., Skehel, J.J., and Smith, M.H. (1985). The molecular basis of the specific anti-influenza action of amantadine. EMBO J 4, 3021–3024.
Helenius, A. (1992). Unpacking the incoming influenza virus. Cell 69, 577–578.
Holsinger, L.J., and Lamb, R.A. (1991). Influenza virus M2 integral membrane protein is a homotetramer stabilized by formation of disulfide bonds. Virology 183, 32–43.
Imai, M., Kawasaki, K., and Odagiri, T. (2008). Cytoplasmic domain of influenza B virus BM2 protein plays critical roles in production of infectious virus. J Virol 82, 728–739.
Imai, M., Watanabe, S., Ninomiya, A., Obuchi, M., and Odagiri, T. (2004). Influenza B virus BM2 protein is a crucial component for incorporation of viral ribonucleoprotein complex into virions during virus assembly. J Virol 78, 11007–11015.
Ito, T., Gorman, O.T., Kawaoka, Y., Bean, W.J., and Webster, R.G. (1991). Evolutionary analysis of the influenza A virus M gene with comparison of the M1 and M2 proteins. J Virol 65, 5491–5498.
Jing, X., Ma, C., Ohigashi, Y., Oliveira, F.A., Jardetzky, T.S., Pinto, L. H., and Lamb, R.A. (2008). Functional studies indicate amantadine binds to the pore of the influenza A virus M2 proton-selective ion channel. Proc Natl Acad Sci U S A 105, 10967–10972.
Kovacs, F.A., Denny, J.K., Song, Z., Quine, J.R., and Cross, T.A. (2000). Helix tilt of the M2 transmembrane peptide from influenza A virus: an intrinsic property. J Mol Biol 295, 117–125.
Kukol, A., Adams, P.D., Rice, L.M., Brunger, A.T., and Arkin, T.I. (1999). Experimentally based orientational refinement of membrane protein models: A structure for the Influenza A M2 H + channel. J Mol Biol 286, 951–962.
Lamb, R.A., Zebedee, S.L., and Richardson, C.D. (1985). Influenza virus M2 protein is an integral membrane protein expressed on the infected-cell surface. Cell 40, 627–633.
Li, C., Qin, H., Gao, F.P., and Cross, T.A. (2007). Solid-state NMR characterization of conformational plasticity within the transmembrane domain of the influenza A M2 proton channel. Biochim Biophys Acta 1768, 3162–3170.
Lin, T.I., and Schroeder, C. (2001). Definitive assignment of proton selectivity and attoampere unitary current to the M2 ion channel protein of influenza A virus. J Virol 75, 3647–3656.
Loria, J.P., Rance, M., and Palmer, A.G., 3rd (1999). A relaxation-compensated carr-purcell-meiboom-gill sequence for characterizing chemical exchange by NMR spectroscopy. J Am Chem Soc 121, 2331–2332.
Ma, C., Polishchuk, A.L., Ohigashi, Y., Stouffer, A.L., Schon, A., Magavern, E., Jing, X., Lear, J.D., Freire, E., Lamb, R.A., et al. (2009). Identification of the functional core of the influenza A virus A/M2 proton-selective ion channel. Proc Natl Acad Sci U S A 106, 12283–12288.
Martin, K., and Helenius, A. (1991). Nuclear transport of influenza virus ribonucleoproteins: the viral matrix protein (M1) promotes export and inhibits import. Cell 67, 117–130.
McCown, M.F., and Pekosz, A. (2006). Distinct domains of the influenza a virus M2 protein cytoplasmic tail mediate binding to the M1 protein and facilitate infectious virus production. J Virol 80, 8178–8189.
Moffat, J.C., Vijayvergiya, V., Gao, P.F., Cross, T.A., Woodbury, D.J., and Busath, D.D. (2008). Proton transport through influenza A virus M2 protein reconstituted in vesicles. Biophys J 94, 434–445.
Mould, J.A., Paterson, R.G., Takeda, M., Ohigashi, Y., Venkataraman, P., Lamb, R.A., and Pinto, L.H. (2003). Influenza B virus BM2 protein has ion channel activity that conducts protons across membranes. Dev Cell 5, 175–184.
Ohigashi, Y., Ma, C., Jing, X., Balannick, V., Pinto, L.H., and Lamb, R. A. (2009). An amantadine-sensitive chimeric BM2 ion channel of influenza B virus has implications for the mechanism of drug inhibition. Proc Natl Acad Sci U S A 106, 18775–18779.
Otomo, K., Toyama, A., Miura, T., and Takeuchi, H. (2009). Interactions between histidine and tryptophan residues in the BM2 proton channel from influenza B virus. J Biochem 145, 543–554.
Oxenoid, K., and Chou, J.J. (2005). The structure of phospholamban pentamer reveals a channel-like architecture in membranes. Proc Natl Acad Sci U S A 102, 10870–10875.
Paterson, R.G., Takeda, M., Ohigashi, Y., Pinto, L.H., and Lamb, R.A. (2003). Influenza B virus BM2 protein is an oligomeric integral membrane protein expressed at the cell surface. Virology 306, 7–17.
Pielak, R.M., Schnell, J.R., and Chou, J.J. (2009). Mechanism of drug inhibition and drug resistance of influenza A M2 channel. Proc Natl Acad Sci U S A 106, 7379–7384.
Pinto, L.H., Dieckmann, G.R., Gandhi, C.S., Papworth, C.G., Braman, J., Shaughnessy, M.A., Lear, J.D., Lamb, R.A., and DeGrado, W.F. (1997). A functionally defined model for the M2 proton channel of influenza A virus suggests a mechanism for its ion selectivity. Proc Natl Acad Sci U S A 94, 11301–11306.
Pinto, L.H., Holsinger, L.J., and Lamb, R.A. (1992). Influenza virus M2 protein has ion channel activity. Cell 69, 517–528.
Sansom, M.S., and Kerr, I.D. (1993). Influenza virus M2 protein: a molecular modelling study of the ion channel. Protein Eng 6, 65–74.
Schnell, J.R., and Chou, J.J. (2008). Structure and mechanism of the M2 proton channel of influenza A virus. Nature 451, 591–595.
Stouffer, A.L., Acharya, R., Salom, D., Levine, A.S., Di Costanzo, L., Soto, C.S., Tereshko, V., Nanda, V., Stayrook, S., and DeGrado, W. F. (2008). Structural basis for the function and inhibition of an influenza virus proton channel. Nature 451, 596–599.
Sugrue, R.J., and Hay, A.J. (1991). Structural characteristics of the M2 protein of influenza A viruses: evidence that it forms a tetrameric channel. Virology 180, 617–624.
Tang, Y., Zaitseva, F., Lamb, R.A., and Pinto, L.H. (2002). The gate of the influenza virus M2 proton channel is formed by a single tryptophan residue. J Biol Chem 277, 39880–39886.
Tarbouriech, N., Curran, J., Ruigrok, R.W., and Burmeister, W.P. (2000). Tetrameric coiled coil domain of Sendai virus phosphoprotein. Nat Struct Biol 7, 777–781.
Tian, C., Gao, P.F., Pinto, L.H., Lamb, R.A., and Cross, T.A. (2003). Initial structural and dynamic characterization of the M2 protein transmembrane and amphipathic helices in lipid bilayers. Protein Sci 12, 2597–2605.
Wang, C., Lamb, R.A., and Pinto, L.H. (1995). Activation of the M2 ion channel of influenza virus: a role for the transmembrane domain histidine residue. Biophys J 69, 1363–1371.
Wang, C., Takeuchi, K., Pinto, L.H., and Lamb, R.A. (1993). Ion channel activity of influenza A virus M2 protein: characterization of the amantadine block. J Virol 67, 5585–5594.
Wang, J., Kim, S., Kovacs, F., and Cross, T.A. (2001). Structure of the transmembrane region of the M2 protein H(+) channel. Protein Sci 10, 2241–2250.
Wang, J., Pielak, R.M., McClintock, M.A., and Chou, J.J. (2009). Solution structure and functional analysis of the influenza B proton channel. Nat Struct Mol Biol 16, 1267–1271.
Watanabe, S., Imai, M., Ohara, Y., and Odagiri, T. (2003). Influenza B virus BM2 protein is transported through the trans-Golgi network as an integral membrane protein. J Virol 77, 10630–10637.
Yi, M., Cross, T.A., and Zhou, H.X. (2008). A secondary gate as a mechanism for inhibition of the m2 proton channel by amantadine. J Phys Chem B 112, 7977–7979.
Yohannan, S., Hu, Y., and Zhou, Y. (2007). Crystallographic study of the tetrabutylammonium block to the KcsA K + channel. J Mol Biol 366, 806–814.
Zhou, M., Morais-Cabral, J.H., Mann, S., and MacKinnon, R. (2001). Potassium channel receptor site for the inactivation gate and quaternary amine inhibitors. Nature 411, 657–661.
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Pielak, R.M., Chou, J.J. Flu channel drug resistance: a tale of two sites. Protein Cell 1, 246–258 (2010). https://doi.org/10.1007/s13238-010-0025-y
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DOI: https://doi.org/10.1007/s13238-010-0025-y