Filamentous influenza virus enters cells via macropinocytosis

Influenza virus is pleiomorphic, producing both spherical (100-nm-diameter) and filamentous (100-nm by 20-μm) virions. While the spherical virions are known to enter host cells through exploitation of clathrin-mediated endocytosis, the entry pathway for filamentous virions has not been determined, t...

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Bibliographic Details
Published in:Journal of virology Vol. 86; no. 20; p. 10950
Main Authors: Rossman, Jeremy S, Leser, George P, Lamb, Robert A
Format: Journal Article
Language:English
Published: United States 01.10.2012
Subjects:
Animals
Cell Line
Dogs
Endocytosis
Endosomes - metabolism
Endosomes - virology
HEK293 Cells
Hepatitis A virus - physiology
Humans
Influenza A Virus, H1N1 Subtype - physiology
Microscopy, Electron
Pinocytosis
Protein Conformation
Viral Fusion Proteins
Viral Matrix Proteins - chemistry
Viral Matrix Proteins - metabolism
Virus Internalization
ISSN:1098-5514, 1098-5514
Online Access:Get more information
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Summary:Influenza virus is pleiomorphic, producing both spherical (100-nm-diameter) and filamentous (100-nm by 20-μm) virions. While the spherical virions are known to enter host cells through exploitation of clathrin-mediated endocytosis, the entry pathway for filamentous virions has not been determined, though the existence of an alternative, non-clathrin-, non-caveolin-mediated entry pathway for influenza virus has been known for many years. In this study, we confirm recent results showing that influenza virus utilizes macropinocytosis as an alternate entry pathway. Furthermore, we find that filamentous influenza viruses use macropinocytosis as the primary entry mechanism. Virions enter cells as intact filaments within macropinosomes and are trafficked to the acidic late-endosomal compartment. Low pH triggers a conformational change in the M2 ion channel protein, altering membrane curvature and leading to a fragmentation of the filamentous virions. This fragmentation may enable more-efficient fusion between the viral and endosomal membranes.
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ISSN:1098-5514
1098-5514
DOI:10.1128/jvi.05992-11