Biophysical Society Thematic Meeting - October 13-15, 2015

Biophysics of Proteins at Surfaces: Assembly, Activation, Signaling

Thursday Speaker Abstracts

Membrane Curvature Induces Scaffolding by BAR-Domain Proteins Mijo Simunovic 1,2 , Henri-François Renard 1 , Jean-Baptiste Manneville 1 , Emma Evergren 3 , Harvey McMahon 3 , Ludger Johannes 1 , Gregory Voth 2 , Jacques Prost 1 , Andrew Callan- Jones 4 , Patricia Bassereau 1 . 1 Institut Curie, Paris, France, 2 University of Chicago, Chicago, IL, USA, 3 MRC, Cambridge, United Kingdom, 4 Université Paris Diderot, Paris, 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 the BAR-domain protein endophilin A2 can scission tubules, which are formed for instance upon 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 shown that endophilin A2 scaffolds and stabilizes tubes in static conditions but induces scission when the tube is dynamically extended. We have also shown that, with our tube assay, scission is independent of the presence of N-terminal amphipathic helices on their BAR domain, in contrast with previous studies on small vesicles.

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