tetano
Editor, Senior Moderator
Langmuir. 2016 Jun 10. [Epub ahead of print]
[h=1]Influenza M2 Transmembrane Domain Senses Membrane Heterogeneity and Enhances Membrane Curvature.[/h] Ho CS, Khadka NK, She F, Cai J, Pan J.
[h=3]Abstract[/h] Targeting host cell membranes by M2 of influenza A virus is important for virus invasion and replication. We study the transmembrane domain of M2 (M2TM) interacting with mica supported planar bilayers and free-standing giant unilamellar vesicles (GUVs). Using solution atomic force microscopy (AFM), we show that the size of M2TM oligomers is dependent on lipid composition. Addition of M2TM to lipid bilayers containing liquid-ordered (Lo) and liquid-disordered (Ld) phases reveals that M2TM preferentially partitions into the Ld phase; phase dependent partitioning results in larger rigidity of the Ld phase. We next use fluorescence microscopy to study effects of M2TM on phase coexisting GUVs. In particular, M2TM is found to increase GUVs' miscibility transition temperature Tmix. The augmented thermodynamic stability can be accounted for by considering an enhanced energy barrier of lipid mixing between coexisting phases. Our GUV study also shows that M2TM can elicit an array of vesicle shapes mimicking virus budding. M2TM enhanced membrane curvature is consistent with our AFM data, which show altered membrane rigidity and consequently line tension at domain edges. Together, our results highlight that in addition to conducting proton, M2TM can actively regulate membrane heterogeneity and augment membrane curvature.
PMID: 27285399 [PubMed - as supplied by publisher]
[h=1]Influenza M2 Transmembrane Domain Senses Membrane Heterogeneity and Enhances Membrane Curvature.[/h] Ho CS, Khadka NK, She F, Cai J, Pan J.
[h=3]Abstract[/h] Targeting host cell membranes by M2 of influenza A virus is important for virus invasion and replication. We study the transmembrane domain of M2 (M2TM) interacting with mica supported planar bilayers and free-standing giant unilamellar vesicles (GUVs). Using solution atomic force microscopy (AFM), we show that the size of M2TM oligomers is dependent on lipid composition. Addition of M2TM to lipid bilayers containing liquid-ordered (Lo) and liquid-disordered (Ld) phases reveals that M2TM preferentially partitions into the Ld phase; phase dependent partitioning results in larger rigidity of the Ld phase. We next use fluorescence microscopy to study effects of M2TM on phase coexisting GUVs. In particular, M2TM is found to increase GUVs' miscibility transition temperature Tmix. The augmented thermodynamic stability can be accounted for by considering an enhanced energy barrier of lipid mixing between coexisting phases. Our GUV study also shows that M2TM can elicit an array of vesicle shapes mimicking virus budding. M2TM enhanced membrane curvature is consistent with our AFM data, which show altered membrane rigidity and consequently line tension at domain edges. Together, our results highlight that in addition to conducting proton, M2TM can actively regulate membrane heterogeneity and augment membrane curvature.
PMID: 27285399 [PubMed - as supplied by publisher]