title: Multiphasic effects of cholesterol on influenza fusion kinetics reflect multiple mechanistic roles.
abstract: The envelope lipid composition of influenza virus differs from that of the cellular plasma membrane from which it buds. Viruses also appear to fuse preferentially to specific membrane compartments, suggesting that the lipid environment may influence permissiveness for fusion. Here, we investigated the influence of the membrane environment on fusion, focusing on cholesterol composition. Strikingly, manipulating cholesterol levels in the viral membrane had different effects on fusion kinetics compared with analogous changes to the target membrane. Increasing cholesterol content in target vesicles increased lipid- and contents-mixing rates. Moderate cholesterol depletion from the viral membrane sped fusion rates, whereas severe depletion slowed the process. The pleiotropic effects of cholesterol include alterations in both membrane-bending moduli and lateral organization. Because influenza virions have demonstrated cholesterol-dependent lateral organization, to separate these effects, we deliberately selected a target vesicle composition that does not support lateral heterogeneity. We therefore postulate that the monotonic response of fusion kinetics to target membrane cholesterol reflects bending and curvature effects, whereas the multiphasic response to viral cholesterol levels reflects the combined effects of lateral organization and material properties.
authors.affiliation: Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia; Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia.
authors.forename: Marta K
authors.initials: MK
authors.lastname: Domanska
authors.forename: Dominik
authors.initials: D
authors.lastname: Wrona
authors.forename: Peter M
authors.initials: PM
authors.lastname: Kasson
mesh_terms: D002784:Cholesterol / Q000378:metabolism*; D007700:Kinetics; D008081:Liposomes / Q000378:metabolism; D009975:Orthomyxoviridae / Q000502:physiology*; D053586:Virus Internalization
chemical_list: D008081:Liposomes; D002784:Cholesterol
references.citation: Nat Rev Mol Cell Biol. 2010 Oct;11(10):688-99
references.pmid: 20861879
references.citation: J Exp Med. 1942 Jan 1;75(1):49-64
references.pmid: 19871167
references.citation: J Cell Biol. 1995 Nov;131(3):679-91
references.pmid: 7593189
references.citation: J Virol. 2007 Jul;81(14):7548-58
references.pmid: 17494071
references.citation: Biophys J. 1997 Jul;73(1):267-76
references.pmid: 9199791
references.citation: Nat Biotechnol. 2008 Oct;26(10):1179-86
references.pmid: 18820684
references.citation: Nat Struct Mol Biol. 2008 Jul;15(7):675-83
references.pmid: 18596814
references.citation: J Gen Physiol. 2008 May;131(5):503-13
references.pmid: 18443361
references.citation: Mol Biol Cell. 1999 Aug;10(8):2759-69
references.pmid: 10436026
references.citation: Proc Natl Acad Sci U S A. 2007 Oct 30;104(44):17370-5
references.pmid: 17959773
references.citation: Biochemistry. 2001 Apr 10;40(14):4340-8
references.pmid: 11284690
references.citation: J Virol. 2003 Dec;77(23):12543-51
references.pmid: 14610177
references.citation: Can J Biochem Physiol. 1959 Aug;37(8):911-7
references.pmid: 13671378
references.citation: Chem Phys Lipids. 2002 Jun;116(1-2):39-55
references.pmid: 12093534
references.citation: Cell. 1994 Jan 28;76(2):383-91
references.pmid: 8293471
references.citation: Annu Rev Cell Dev Biol. 1996;12:627-61
references.pmid: 8970739
references.citation: Proc Natl Acad Sci U S A. 1993 Jun 1;90(11):5181-5
references.pmid: 8389472
references.citation: J Cell Biol. 2012 Jan 23;196(2):213-21
references.pmid: 22249292
references.citation: J Cell Sci. 2010 Feb 15;123(Pt 4):595-605
references.pmid: 20103534
references.citation: Nat Chem Biol. 2008 Apr;4(4):248-55
references.pmid: 18311130
references.citation: J Cell Biol. 1996 May;133(3):559-69
references.pmid: 8636231
references.citation: J Gen Virol. 2006 Feb;87(Pt 2):277-285
references.pmid: 16432012
references.citation: Biophys J. 2007 Apr 15;92(8):2819-30
references.pmid: 17259270
references.citation: Annu Rev Biochem. 2000;69:531-69
references.pmid: 10966468
references.citation: Science. 2010 Jan 1;327(5961):46-50
references.pmid: 20044567
references.citation: Biochim Biophys Acta. 2007 Jun;1768(6):1311-24
references.pmid: 17493580
references.citation: Biochim Biophys Acta. 2004 May 27;1663(1-2):188-200
references.pmid: 15157621
references.citation: Biophys J. 2002 Feb;82(2):882-95
references.pmid: 11806930
references.citation: Proc Natl Acad Sci U S A. 2003 Dec 9;100(25):14610-7
references.pmid: 14561897
references.citation: Commun Integr Biol. 2010 Jul;3(4):352-3
references.pmid: 20798824