Abstract
Our results show that the mechanism by which influenza virus fuses with target membranes involves sequential complex changes in the hemagglutinin (HA, the viral fusion protein) and in the contact site between virus and target membrane. To render individual steps amenable to study, we worked at 0 degree C which decreased the rate of fusion and increased the efficiency. The mechanism of fusion at 0 degree C and 37 degrees C was similar. The process began with a conformational change in HA which exposed the fusion peptides but did not lead to dissociation of the tops of the ectodomain of the trimer. The change in the protein led to immediate hydrophobic attachment of the virus to the target liposomes. Attachment was followed by a lag period (4-8 min at 0 degree C, 0.6-2 s at 37 degrees C) during which rearrangements occurred in the site of membrane contact between the virus and liposome. After a further series of changes the final bilayer merger took place. This final fusion event was not pH dependent. At 0 degree C efficient fusion occurred without dissociation of the top domains of the HA trimer, suggesting that a transient conformation of HA is responsible for fusion at physiological temperatures. The observations lead to a revised model for HA mediated fusion.
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- Brunner J. Testing topological models for the membrane penetration of the fusion peptide of influenza virus hemagglutinin. FEBS Lett. 1989 Nov 6;257(2):369–372. doi: 10.1016/0014-5793(89)81574-1. [DOI] [PubMed] [Google Scholar]
- Burger K. N., Knoll G., Verkleij A. J. Influenza virus-model membrane interaction. A morphological approach using modern cryotechniques. Biochim Biophys Acta. 1988 Mar 22;939(1):89–101. doi: 10.1016/0005-2736(88)90050-8. [DOI] [PubMed] [Google Scholar]
- Clague M. J., Schoch C., Zech L., Blumenthal R. Gating kinetics of pH-activated membrane fusion of vesicular stomatitis virus with cells: stopped-flow measurements by dequenching of octadecylrhodamine fluorescence. Biochemistry. 1990 Feb 6;29(5):1303–1308. doi: 10.1021/bi00457a028. [DOI] [PubMed] [Google Scholar]
- Copeland C. S., Doms R. W., Bolzau E. M., Webster R. G., Helenius A. Assembly of influenza hemagglutinin trimers and its role in intracellular transport. J Cell Biol. 1986 Oct;103(4):1179–1191. doi: 10.1083/jcb.103.4.1179. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Daniels R. S., Douglas A. R., Skehel J. J., Wiley D. C. Analyses of the antigenicity of influenza haemagglutinin at the pH optimum for virus-mediated membrane fusion. J Gen Virol. 1983 Aug;64(Pt 8):1657–1662. doi: 10.1099/0022-1317-64-8-1657. [DOI] [PubMed] [Google Scholar]
- Doms R. W., Gething M. J., Henneberry J., White J., Helenius A. Variant influenza virus hemagglutinin that induces fusion at elevated pH. J Virol. 1986 Feb;57(2):603–613. doi: 10.1128/jvi.57.2.603-613.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Doms R. W., Helenius A. Quaternary structure of influenza virus hemagglutinin after acid treatment. J Virol. 1986 Dec;60(3):833–839. doi: 10.1128/jvi.60.3.833-839.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ellens H., Bentz J., Mason D., Zhang F., White J. M. Fusion of influenza hemagglutinin-expressing fibroblasts with glycophorin-bearing liposomes: role of hemagglutinin surface density. Biochemistry. 1990 Oct 16;29(41):9697–9707. doi: 10.1021/bi00493a027. [DOI] [PubMed] [Google Scholar]
- FOLCH J., LEES M., SLOANE STANLEY G. H. A simple method for the isolation and purification of total lipides from animal tissues. J Biol Chem. 1957 May;226(1):497–509. [PubMed] [Google Scholar]
- Goud B., Salminen A., Walworth N. C., Novick P. J. A GTP-binding protein required for secretion rapidly associates with secretory vesicles and the plasma membrane in yeast. Cell. 1988 Jun 3;53(5):753–768. doi: 10.1016/0092-8674(88)90093-1. [DOI] [PubMed] [Google Scholar]
- Green N., Alexander H., Olson A., Alexander S., Shinnick T. M., Sutcliffe J. G., Lerner R. A. Immunogenic structure of the influenza virus hemagglutinin. Cell. 1982 Mar;28(3):477–487. doi: 10.1016/0092-8674(82)90202-1. [DOI] [PubMed] [Google Scholar]
- Harter C., James P., Bächi T., Semenza G., Brunner J. Hydrophobic binding of the ectodomain of influenza hemagglutinin to membranes occurs through the "fusion peptide". J Biol Chem. 1989 Apr 15;264(11):6459–6464. [PubMed] [Google Scholar]
- Hoekstra D., de Boer T., Klappe K., Wilschut J. Fluorescence method for measuring the kinetics of fusion between biological membranes. Biochemistry. 1984 Nov 20;23(24):5675–5681. doi: 10.1021/bi00319a002. [DOI] [PubMed] [Google Scholar]
- Junankar P. R., Cherry R. J. Temperature and pH dependence of the haemolytic activity of influenza virus and of the rotational mobility of the spike glycoproteins. Biochim Biophys Acta. 1986 Jan 29;854(2):198–206. doi: 10.1016/0005-2736(86)90111-2. [DOI] [PubMed] [Google Scholar]
- Malhotra V., Orci L., Glick B. S., Block M. R., Rothman J. E. Role of an N-ethylmaleimide-sensitive transport component in promoting fusion of transport vesicles with cisternae of the Golgi stack. Cell. 1988 Jul 15;54(2):221–227. doi: 10.1016/0092-8674(88)90554-5. [DOI] [PubMed] [Google Scholar]
- 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]
- Mayer L. D., Hope M. J., Cullis P. R. Vesicles of variable sizes produced by a rapid extrusion procedure. Biochim Biophys Acta. 1986 Jun 13;858(1):161–168. doi: 10.1016/0005-2736(86)90302-0. [DOI] [PubMed] [Google Scholar]
- Morris S. J., Sarkar D. P., White J. M., Blumenthal R. Kinetics of pH-dependent fusion between 3T3 fibroblasts expressing influenza hemagglutinin and red blood cells. Measurement by dequenching of fluorescence. J Biol Chem. 1989 Mar 5;264(7):3972–3978. [PubMed] [Google Scholar]
- Sarkar D. P., Morris S. J., Eidelman O., Zimmerberg J., Blumenthal R. Initial stages of influenza hemagglutinin-induced cell fusion monitored simultaneously by two fluorescent events: cytoplasmic continuity and lipid mixing. J Cell Biol. 1989 Jul;109(1):113–122. doi: 10.1083/jcb.109.1.113. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sato S. B., Kawasaki K., Ohnishi S. Hemolytic activity of influenza virus hemagglutinin glycoproteins activated in mildly acidic environments. Proc Natl Acad Sci U S A. 1983 Jun;80(11):3153–3157. doi: 10.1073/pnas.80.11.3153. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Scholtissek C. Stability of infectious influenza A viruses at low pH and at elevated temperature. Vaccine. 1985 Sep;3(3 Suppl):215–218. doi: 10.1016/0264-410x(85)90109-4. [DOI] [PubMed] [Google Scholar]
- Skehel J. J., Bayley P. M., Brown E. B., Martin S. R., Waterfield M. D., White J. M., Wilson I. A., Wiley D. C. Changes in the conformation of influenza virus hemagglutinin at the pH optimum of virus-mediated membrane fusion. Proc Natl Acad Sci U S A. 1982 Feb;79(4):968–972. doi: 10.1073/pnas.79.4.968. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Spruce A. E., Iwata A., White J. M., Almers W. Patch clamp studies of single cell-fusion events mediated by a viral fusion protein. Nature. 1989 Nov 30;342(6249):555–558. doi: 10.1038/342555a0. [DOI] [PubMed] [Google Scholar]
- Steck T. L., Kant J. A. Preparation of impermeable ghosts and inside-out vesicles from human erythrocyte membranes. Methods Enzymol. 1974;31:172–180. doi: 10.1016/0076-6879(74)31019-1. [DOI] [PubMed] [Google Scholar]
- Stegmann T., Booy F. P., Wilschut J. Effects of low pH on influenza virus. Activation and inactivation of the membrane fusion capacity of the hemagglutinin. J Biol Chem. 1987 Dec 25;262(36):17744–17749. [PubMed] [Google Scholar]
- Stegmann T., Doms R. W., Helenius A. Protein-mediated membrane fusion. Annu Rev Biophys Biophys Chem. 1989;18:187–211. doi: 10.1146/annurev.bb.18.060189.001155. [DOI] [PubMed] [Google Scholar]
- Stegmann T., Hoekstra D., Scherphof G., Wilschut J. Fusion activity of influenza virus. A comparison between biological and artificial target membrane vesicles. J Biol Chem. 1986 Aug 25;261(24):10966–10969. [PubMed] [Google Scholar]
- Stegmann T., Hoekstra D., Scherphof G., Wilschut J. Kinetics of pH-dependent fusion between influenza virus and liposomes. Biochemistry. 1985 Jun 18;24(13):3107–3113. doi: 10.1021/bi00334a006. [DOI] [PubMed] [Google Scholar]
- Stegmann T., Nir S., Wilschut J. Membrane fusion activity of influenza virus. Effects of gangliosides and negatively charged phospholipids in target liposomes. Biochemistry. 1989 Feb 21;28(4):1698–1704. doi: 10.1021/bi00430a041. [DOI] [PubMed] [Google Scholar]
- Struck D. K., Hoekstra D., Pagano R. E. Use of resonance energy transfer to monitor membrane fusion. Biochemistry. 1981 Jul 7;20(14):4093–4099. doi: 10.1021/bi00517a023. [DOI] [PubMed] [Google Scholar]
- Webster R. G., Brown L. E., Jackson D. C. Changes in the antigenicity of the hemagglutinin molecule of H3 influenza virus at acidic pH. Virology. 1983 Apr 30;126(2):587–599. doi: 10.1016/s0042-6822(83)80015-4. [DOI] [PubMed] [Google Scholar]
- Wharton S. A., Skehel J. J., Wiley D. C. Studies of influenza haemagglutinin-mediated membrane fusion. Virology. 1986 Feb;149(1):27–35. doi: 10.1016/0042-6822(86)90083-8. [DOI] [PubMed] [Google Scholar]
- White J. M. Viral and cellular membrane fusion proteins. Annu Rev Physiol. 1990;52:675–697. doi: 10.1146/annurev.ph.52.030190.003331. [DOI] [PubMed] [Google Scholar]
- White J. M., Wilson I. A. Anti-peptide antibodies detect steps in a protein conformational change: low-pH activation of the influenza virus hemagglutinin. J Cell Biol. 1987 Dec;105(6 Pt 2):2887–2896. doi: 10.1083/jcb.105.6.2887. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 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]
- Wiley D. C., Skehel J. J. The structure and function of the hemagglutinin membrane glycoprotein of influenza virus. Annu Rev Biochem. 1987;56:365–394. doi: 10.1146/annurev.bi.56.070187.002053. [DOI] [PubMed] [Google Scholar]
- Wiley D. C., Wilson I. A., Skehel J. J. Structural identification of the antibody-binding sites of Hong Kong influenza haemagglutinin and their involvement in antigenic variation. Nature. 1981 Jan 29;289(5796):373–378. doi: 10.1038/289373a0. [DOI] [PubMed] [Google Scholar]
- Wilson I. A., Niman H. L., Houghten R. A., Cherenson A. R., Connolly M. L., Lerner R. A. The structure of an antigenic determinant in a protein. Cell. 1984 Jul;37(3):767–778. doi: 10.1016/0092-8674(84)90412-4. [DOI] [PubMed] [Google Scholar]
- Wilson I. A., Skehel J. J., Wiley D. C. Structure of the haemagglutinin membrane glycoprotein of influenza virus at 3 A resolution. Nature. 1981 Jan 29;289(5796):366–373. doi: 10.1038/289366a0. [DOI] [PubMed] [Google Scholar]