Mimicking Influenza Virus Fusion Using Supported Lipid Bilayers

Abstract

Influenza virus infection is a serious public health problem in the world, and understanding the molecular mechanisms involved in viral replication is crucial. In this paper, we used a minimalist approach based on a lipid bilayer supported on mica, which we imaged by atomic force microscopy (AFM) in a physiological buffer, to analyze the different steps of influenza fusion, from the interaction of intact viruses with the supported bilayer to their complete fusion. Our results show that sialic acid recognition and priming upon acidification are sufficient for a complete fusion with the host cell membrane. After fusion, a flat and continuous membrane was observed. Because of the fragility of the viral membrane that was removed by the tip, most probably due to the disorganization of the matrix layer at acidic pH, fine structural details of ribonucleoproteins (RNP) were obtained. In addition, AFM topography of intact virus in interaction with the supported lipid bilayer confirms that hemeagglutinin and neuraminidase can form isolated clusters within the viral membrane.

Observation of Liquid–Liquid-Phase Separation and Vesicle Spreading during Supported Bilayer Formation via Liquid-Phase Transmission Electron Microscopy

“…Supported bilayers (SBs) are materials made of amphiphilic molecules such as lipids and block copolymers, held together by noncovalent interactions with a substrate. − SBs display diverse physical and chemical properties and have been used to study membrane properties such as ligand–receptor interactions, , viral attacks, and cellular signaling . Furthermore, SBs enable surface-sensitive measurements, such as acoustic, optical, plasmonic, and chemical sensing .…”

Cholesterol of lipid rafts is a key determinant for entry and post-entry control of porcine rotavirus infection

“…Recent reports have demonstrated the involvement of lipids in a variety of cellular functions such as apical cell-sorting of proteins, signal transduction, caveolae mediated endocytosis, and viral release, assembly and budding in the cell membrane. These have been well documented in human immunodeficiency virus (HIV) [ 9 ], measles virus [ 10 ], influenza virus [ 11 – 13 ] and rotavirus [ 7 , 14 ]. Lipids have also been deemed important in intracellular trafficking of viral proteins [ 15 – 18 ] (e.g.…”

Microcavity array supported lipid bilayer models of ganglioside – influenza hemagglutinin1 binding

“…HA 1 receptor. 13,14 However, the role of the host cell membrane composition as well its fluidity in promoting or inhibiting influenza virus HA -glycan association has not been fully elucidated. [15][16][17] It has been shown, in liposomes, for example, that the transmembrane domain of HA partitions selectively to liquid ordered (L o ) domains, and in turn manifests clustering and budding of virus,a pathway for viral replication mediated potentially, by lipid rafts.…”