Regensburg 2019 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 2: Membranes and vesicles I (joint session BP/CPP)

BP 2.9: Vortrag

Montag, 1. April 2019, 12:15–12:30, H10

Influenza A matrix protein (M1) multimerization is the main driving force for membrane bending and tubulation. — Ismail Dahmani, Kai Ludwig, and •Salvatore Chiantia — Cell Membrane Biophysics Group / Universität Potsdam Karl-Liebknecht-Str. 24-25, Haus 25, B/1.04 14476 Potsdam-Golm Deutschland

The matrix protein of the Influenza A virus (M1) forms a shell underlying the viral lipid envelope and controls the geometry of the virus capsid. In infected cells, M1 orchestrates the process of new virion formation by binding to the inner leaflet of the plasma membrane (PM), which finally results in bending of the lipid bilayer and virus release . The exact role of M1 polymerization in inducing membrane deformation and budding is not clear. Here, to model virus egress through the PM, we analyzed M1 binding to giant unilamellar vesicles (GUVs). Our results show that M1 and a construct consisting of its Nterminal domain (NM1) bind to negatively charged lipids causing unidirectional deformation by imposing an inward curvature and membrane tabulation . Detergent-mediated solubilization of the lipid bilayer after M1 binding leaves the three-dimensional organization of the protein intact, indicating that M1 forms a very stable network adjacent and independent from the lipid membrane. Our data also indicate that the C-terminal domain of M1 is not needed for the establishment of protein-protein interactions and membrane deformation. Finally in acidic conditions (pH=5) M1 irreversibly loses its ability to multimerize and induce curvature, thus confirming that M1 multimerization is the molecular mechanism responsible for membrane deformation.