Skip to main content
NCBI home page
Journal of Virology logoLink to Journal of Virology
. 1996 Dec;70(12):8391–8401. doi: 10.1128/jvi.70.12.8391-8401.1996

Effect of M1 protein and low pH on nuclear transport of influenza virus ribonucleoproteins.

M Bui 1, G Whittaker 1, A Helenius 1
PMCID: PMC190928  PMID: 8970960

Abstract

Influenza virus enters its host cell by receptor-mediated endocytosis followed by acid-activated membrane fusion in endosomes. The viral ribonucleoprotein particles (vRNPs) delivered into the cytosol then dissociate from the matrix protein, M1, and from each other, after which they are individually imported into the nucleus via the nuclear pores. For some time, it has been believed that the low pH in endosomes may, in some way, trigger the capsid disassembly events necessary for nuclear transport. This report provides direct evidence that the association of M1 with vRNPs is sensitive to mildly acidic pH within the infected cell. Recombinant M1, expressed in cultured cells, was found to associate with vRNPs and inhibit their nuclear import. Brief acidification of the cytosolic compartment eliminated the interfering activity and allowed the incoming vRNPs to enter the nucleus. Newly assembled progeny M1-vRNP complexes in the cytosol of infected cells were also dissociated by brief acidification. Acidic pH was thus found to serve as a switch that allowed M1 to carry out its multiple functions in the uncoating, nuclear transport, and assembly of vRNPs.

Full Text

The Full Text of this article is available as a PDF (1.3 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Boron W. F. Intracellular pH transients in giant barnacle muscle fibers. Am J Physiol. 1977 Sep;233(3):C61–C73. doi: 10.1152/ajpcell.1977.233.3.C61. [DOI] [PubMed] [Google Scholar]
  2. Bukrinskaya A. G., Vorkunova N. K., Kornilayeva G. V., Narmanbetova R. A., Vorkunova G. K. Influenza virus uncoating in infected cells and effect of rimantadine. J Gen Virol. 1982 May;60(Pt 1):49–59. doi: 10.1099/0022-1317-60-1-49. [DOI] [PubMed] [Google Scholar]
  3. Compans R. W., Content J., Duesberg P. H. Structure of the ribonucleoprotein of influenza virus. J Virol. 1972 Oct;10(4):795–800. doi: 10.1128/jvi.10.4.795-800.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Davey J., Dimmock N. J., Colman A. Identification of the sequence responsible for the nuclear accumulation of the influenza virus nucleoprotein in Xenopus oocytes. Cell. 1985 Mar;40(3):667–675. doi: 10.1016/0092-8674(85)90215-6. [DOI] [PubMed] [Google Scholar]
  5. Davidson R. L., Gerald P. S. Improved techniques for the induction of mammalian cell hybridization by polyethylene glycol. Somatic Cell Genet. 1976 Mar;2(2):165–176. doi: 10.1007/BF01542629. [DOI] [PubMed] [Google Scholar]
  6. Duesberg P. H. Distinct subunits of the ribonucleoprotein of influenza virus. J Mol Biol. 1969 Jun 28;42(3):485–499. doi: 10.1016/0022-2836(69)90237-x. [DOI] [PubMed] [Google Scholar]
  7. Elster C., Fourest E., Baudin F., Larsen K., Cusack S., Ruigrok R. W. A small percentage of influenza virus M1 protein contains zinc but zinc does not influence in vitro M1-RNA interaction. J Gen Virol. 1994 Jan;75(Pt 1):37–42. doi: 10.1099/0022-1317-75-1-37. [DOI] [PubMed] [Google Scholar]
  8. Guinea R., Carrasco L. Requirement for vacuolar proton-ATPase activity during entry of influenza virus into cells. J Virol. 1995 Apr;69(4):2306–2312. doi: 10.1128/jvi.69.4.2306-2312.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Hay A. J., Wolstenholme A. J., Skehel J. J., Smith M. H. The molecular basis of the specific anti-influenza action of amantadine. EMBO J. 1985 Nov;4(11):3021–3024. doi: 10.1002/j.1460-2075.1985.tb04038.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Helenius A. Unpacking the incoming influenza virus. Cell. 1992 May 15;69(4):577–578. doi: 10.1016/0092-8674(92)90219-3. [DOI] [PubMed] [Google Scholar]
  11. Heuser J. Effects of cytoplasmic acidification on clathrin lattice morphology. J Cell Biol. 1989 Feb;108(2):401–411. doi: 10.1083/jcb.108.2.401. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Jennings P. A., Finch J. T., Winter G., Robertson J. S. Does the higher order structure of the influenza virus ribonucleoprotein guide sequence rearrangements in influenza viral RNA? Cell. 1983 Sep;34(2):619–627. doi: 10.1016/0092-8674(83)90394-x. [DOI] [PubMed] [Google Scholar]
  13. Kann M., Lu X., Gerlich W. H. Recent studies on replication of hepatitis B virus. J Hepatol. 1995;22(1 Suppl):9–13. [PubMed] [Google Scholar]
  14. Kato N., Eggers H. J. Inhibition of uncoating of fowl plague virus by l-adamantanamine hydrochloride. Virology. 1969 Apr;37(4):632–641. doi: 10.1016/0042-6822(69)90281-5. [DOI] [PubMed] [Google Scholar]
  15. Kemler I., Whittaker G., Helenius A. Nuclear import of microinjected influenza virus ribonucleoproteins. Virology. 1994 Aug 1;202(2):1028–1033. doi: 10.1006/viro.1994.1432. [DOI] [PubMed] [Google Scholar]
  16. Koff W. C., Knight V. Inhibition of influenza virus uncoating by rimantadine hydrochloride. J Virol. 1979 Jul;31(1):261–263. doi: 10.1128/jvi.31.1.261-263.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Lamb R. A., Zebedee S. L., Richardson C. D. Influenza virus M2 protein is an integral membrane protein expressed on the infected-cell surface. Cell. 1985 Mar;40(3):627–633. doi: 10.1016/0092-8674(85)90211-9. [DOI] [PubMed] [Google Scholar]
  18. Li R. A., Palese P., Krystal M. Complementation and analysis of an NP mutant of influenza virus. Virus Res. 1989 Feb;12(2):97–111. doi: 10.1016/0168-1702(89)90057-9. [DOI] [PubMed] [Google Scholar]
  19. Li R. H., Thomas J. O. Identification of a human protein that interacts with nuclear localization signals. J Cell Biol. 1989 Dec;109(6 Pt 1):2623–2632. doi: 10.1083/jcb.109.6.2623. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Maeda T., Kawasaki K., Ohnishi S. Interaction of influenza virus hemagglutinin with target membrane lipids is a key step in virus-induced hemolysis and fusion at pH 5.2. Proc Natl Acad Sci U S A. 1981 Jul;78(7):4133–4137. doi: 10.1073/pnas.78.7.4133. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Marsh M., Helenius A. Virus entry into animal cells. Adv Virus Res. 1989;36:107–151. doi: 10.1016/S0065-3527(08)60583-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Martin K., Helenius A. Nuclear transport of influenza virus ribonucleoproteins: the viral matrix protein (M1) promotes export and inhibits import. Cell. 1991 Oct 4;67(1):117–130. doi: 10.1016/0092-8674(91)90576-k. [DOI] [PubMed] [Google Scholar]
  23. Martin K., Helenius A. Transport of incoming influenza virus nucleocapsids into the nucleus. J Virol. 1991 Jan;65(1):232–244. doi: 10.1128/jvi.65.1.232-244.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Matlin K. S., Reggio H., Helenius A., Simons K. Infectious entry pathway of influenza virus in a canine kidney cell line. J Cell Biol. 1981 Dec;91(3 Pt 1):601–613. doi: 10.1083/jcb.91.3.601. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Murti K. G., Bean W. J., Jr, Webster R. G. Helical ribonucleoproteins of influenza virus: an electron microscopic analysis. Virology. 1980 Jul 15;104(1):224–229. doi: 10.1016/0042-6822(80)90380-3. [DOI] [PubMed] [Google Scholar]
  26. Nassal M., Schaller H. Hepatitis B virus replication. Trends Microbiol. 1993 Sep;1(6):221–228. doi: 10.1016/0966-842x(93)90136-f. [DOI] [PubMed] [Google Scholar]
  27. O'Neill R. E., Jaskunas R., Blobel G., Palese P., Moroianu J. Nuclear import of influenza virus RNA can be mediated by viral nucleoprotein and transport factors required for protein import. J Biol Chem. 1995 Sep 29;270(39):22701–22704. doi: 10.1074/jbc.270.39.22701. [DOI] [PubMed] [Google Scholar]
  28. O'Neill R. E., Palese P. NPI-1, the human homolog of SRP-1, interacts with influenza virus nucleoprotein. Virology. 1995 Jan 10;206(1):116–125. doi: 10.1016/s0042-6822(95)80026-3. [DOI] [PubMed] [Google Scholar]
  29. Ohkuma S., Poole B. Fluorescence probe measurement of the intralysosomal pH in living cells and the perturbation of pH by various agents. Proc Natl Acad Sci U S A. 1978 Jul;75(7):3327–3331. doi: 10.1073/pnas.75.7.3327. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Patterson S., Gross J., Oxford J. S. The intracellular distribution of influenza virus matrix protein and nucleoprotein in infected cells and their relationship to haemagglutinin in the plasma membrane. J Gen Virol. 1988 Aug;69(Pt 8):1859–1872. doi: 10.1099/0022-1317-69-8-1859. [DOI] [PubMed] [Google Scholar]
  31. Pinto L. H., Holsinger L. J., Lamb R. A. Influenza virus M2 protein has ion channel activity. Cell. 1992 May 1;69(3):517–528. doi: 10.1016/0092-8674(92)90452-i. [DOI] [PubMed] [Google Scholar]
  32. Plotch S. J., Bouloy M., Ulmanen I., Krug R. M. A unique cap(m7GpppXm)-dependent influenza virion endonuclease cleaves capped RNAs to generate the primers that initiate viral RNA transcription. Cell. 1981 Mar;23(3):847–858. doi: 10.1016/0092-8674(81)90449-9. [DOI] [PubMed] [Google Scholar]
  33. Rees P. J., Dimmock N. J. Electrophoretic separation of influenza virus ribonucleoproteins. J Gen Virol. 1981 Mar;53(Pt 1):125–132. doi: 10.1099/0022-1317-53-1-125. [DOI] [PubMed] [Google Scholar]
  34. Rink T. J., Tsien R. Y., Pozzan T. Cytoplasmic pH and free Mg2+ in lymphocytes. J Cell Biol. 1982 Oct;95(1):189–196. doi: 10.1083/jcb.95.1.189. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. Rochovansky O. M. RNA synthesis by ribonucleoprotein-polymerase complexes isolated from influenza virus. Virology. 1976 Sep;73(2):327–338. doi: 10.1016/0042-6822(76)90394-9. [DOI] [PubMed] [Google Scholar]
  36. Sandvig K., Olsnes S., Petersen O. W., van Deurs B. Acidification of the cytosol inhibits endocytosis from coated pits. J Cell Biol. 1987 Aug;105(2):679–689. doi: 10.1083/jcb.105.2.679. [DOI] [PMC free article] [PubMed] [Google Scholar]
  37. Schroeder C., Ford C. M., Wharton S. A., Hay A. J. Functional reconstitution in lipid vesicles of influenza virus M2 protein expressed by baculovirus: evidence for proton transfer activity. J Gen Virol. 1994 Dec;75(Pt 12):3477–3484. doi: 10.1099/0022-1317-75-12-3477. [DOI] [PubMed] [Google Scholar]
  38. Schulze I. T. The structure of influenza virus. I. The polypeptides of the virion. Virology. 1970 Dec;42(4):890–904. doi: 10.1016/0042-6822(70)90338-7. [DOI] [PubMed] [Google Scholar]
  39. Shimbo K., Brassard D. L., Lamb R. A., Pinto L. H. Ion selectivity and activation of the M2 ion channel of influenza virus. Biophys J. 1996 Mar;70(3):1335–1346. doi: 10.1016/S0006-3495(96)79690-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
  40. Singh I., Helenius A. Role of ribosomes in Semliki Forest virus nucleocapsid uncoating. J Virol. 1992 Dec;66(12):7049–7058. doi: 10.1128/jvi.66.12.7049-7058.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Skehel J. J. Influenza virus. Amantadine blocks the channel. Nature. 1992 Jul 9;358(6382):110–111. doi: 10.1038/358110b0. [DOI] [PubMed] [Google Scholar]
  42. Sugrue R. J., Bahadur G., Zambon M. C., Hall-Smith M., Douglas A. R., Hay A. J. Specific structural alteration of the influenza haemagglutinin by amantadine. EMBO J. 1990 Nov;9(11):3469–3476. doi: 10.1002/j.1460-2075.1990.tb07555.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  43. Sugrue R. J., Hay A. J. Structural characteristics of the M2 protein of influenza A viruses: evidence that it forms a tetrameric channel. Virology. 1991 Feb;180(2):617–624. doi: 10.1016/0042-6822(91)90075-M. [DOI] [PMC free article] [PubMed] [Google Scholar]
  44. Wakefield L., Brownlee G. G. RNA-binding properties of influenza A virus matrix protein M1. Nucleic Acids Res. 1989 Nov 11;17(21):8569–8580. doi: 10.1093/nar/17.21.8569. [DOI] [PMC free article] [PubMed] [Google Scholar]
  45. Wang C., Lamb R. A., Pinto L. H. Direct measurement of the influenza A virus M2 protein ion channel activity in mammalian cells. Virology. 1994 Nov 15;205(1):133–140. doi: 10.1006/viro.1994.1628. [DOI] [PubMed] [Google Scholar]
  46. Wang C., Takeuchi K., Pinto L. H., Lamb R. A. Ion channel activity of influenza A virus M2 protein: characterization of the amantadine block. J Virol. 1993 Sep;67(9):5585–5594. doi: 10.1128/jvi.67.9.5585-5594.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
  47. White J., Kartenbeck J., Helenius A. Membrane fusion activity of influenza virus. EMBO J. 1982;1(2):217–222. doi: 10.1002/j.1460-2075.1982.tb01150.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  48. Whittaker G., Bui M., Helenius A. Nuclear trafficking of influenza virus ribonuleoproteins in heterokaryons. J Virol. 1996 May;70(5):2743–2756. doi: 10.1128/jvi.70.5.2743-2756.1996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  49. Whittaker G., Bui M., Helenius A. The role of nuclear import and export in influenza virus infection. Trends Cell Biol. 1996 Feb;6(2):67–71. doi: 10.1016/0962-8924(96)81017-8. [DOI] [PubMed] [Google Scholar]
  50. Wu X. J., Beachy R. N., Wilson T. M., Shaw J. G. Inhibition of uncoating of tobacco mosaic virus particles in protoplasts from transgenic tobacco plants that express the viral coat protein gene. Virology. 1990 Dec;179(2):893–895. doi: 10.1016/0042-6822(90)90163-l. [DOI] [PubMed] [Google Scholar]
  51. Ye Z. P., Pal R., Fox J. W., Wagner R. R. Functional and antigenic domains of the matrix (M1) protein of influenza A virus. J Virol. 1987 Feb;61(2):239–246. doi: 10.1128/jvi.61.2.239-246.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  52. Zhirnov O. P. Isolation of matrix protein M1 from influenza viruses by acid-dependent extraction with nonionic detergent. Virology. 1992 Jan;186(1):324–330. doi: 10.1016/0042-6822(92)90090-c. [DOI] [PubMed] [Google Scholar]
  53. Zhirnov O. P. Solubilization of matrix protein M1/M from virions occurs at different pH for orthomyxo- and paramyxoviruses. Virology. 1990 May;176(1):274–279. doi: 10.1016/0042-6822(90)90253-n. [DOI] [PubMed] [Google Scholar]
  54. Zvonarjev A. Y., Ghendon Y. Z. Influence of membrane (M) protein on influenza A virus virion transcriptase activity in vitro and its susceptibility to rimantadine. J Virol. 1980 Feb;33(2):583–586. doi: 10.1128/jvi.33.2.583-586.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Journal of Virology are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES