Berlin 2015 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 18: Membranes and vesicles I (joint BP/CPP)
BP 18.1: Hauptvortrag
Dienstag, 17. März 2015, 09:30–10:00, H 1028
Multifaceted BAR-domain proteins to shape cell membranes — Coline Prévost1, Mijo Simunovic1,2, Henri-François Renard1, Emma Evergren3, Harvey McMahon3, Ludger Johannes1, Jacques Prost1, Andrew Callan-Jones4, and •Patricia Bassereau1 — 1Institut Curie, Paris, France — 2University of Chicago, USA — 3MRC, Cambridge, UK — 4University Paris-Diderot, France
Cell plasma membranes are highly deformable and are strongly curved upon membrane trafficking or during cell motility. BAR-domain proteins with their intrinsically curved shape and their interaction with the actin cytoskeleton are involved in many of these processes.We have used in vitro experiments to study the interaction of BAR-domain proteins with curved membranes for understanding how inverted-BAR domain proteins such as IRSp53 are involved in the generation of filopodia and how the BAR-domain protein endophilin A2 can scission tubules induced by Shiga toxin internalization. We have pulled membrane nanotubes of controlled curvature from Giant Unilamellar Vesicles (GUVs) using optical tweezers and micropipette aspiration. With this approach coupled to theoretical modeling, we have evidenced for IRSp53 a protein phase separation along the nanotube occurring at low protein density for weakly curved membranes. It can explain the in vivo local clustering of the protein, a primary step in filopodia generation that precedes the recruitment of other partners. We have also shown that endophilin A2 scaffolds and stabilizes tubes in static conditions but induces scission when the tube is dynamically extended.