Single-particle kinetics of influenza virus membrane fusion

Authors

Daniel L. Floyd, Harvard Medical School
Justin R. Ragains, Harvard Medical School
John J. Skehel, MRC National Institute of Medical Research
Stephen C. Harrison, Harvard Medical School
Antoine M. van Oijen, Harvard Medical SchoolFollow

RIS ID

94071

Publication Details

Floyd, D. L., Ragains, J. R., Skehel, J. J., Harrison, S. C. & van Oijen, A. M. (2008). Single-particle kinetics of influenza virus membrane fusion. Proceedings of the National Academy of Sciences of USA, 105 (40), 15382-15387.

Abstract

Membrane fusion is an essential step during entry of enveloped viruses into cells. Conventional fusion assays are generally limited to observation of ensembles of multiple fusion events, confounding more detailed analysis of the sequence of the molecular steps involved. We have developed an in vitro, two-color fluorescence assay to monitor kinetics of single virus particles fusing with a target bilayer on an essentially fluid support. Analysis of lipid- and content-mixing trajectories on a particle-by-particle basis provides evidence for multiple, long-lived kinetic intermediates leading to hemifusion, followed by a single, rate-limiting step to pore formation. We interpret the series of intermediates preceding hemifusion as a result of the requirement that multiple copies of the trimeric hemagglutinin fusion protein be activated to initiate the fusion process.