Our group studies the role of membranes in essential cellfunctions such as intracellular transport, cell infection oraction potential propagation. Our experiments are based on reconstituted membrane systems (Giant Unilamellar Vesicles (GUV), membrane nanotubes) and purified proteins. We study the shaping effect of proteins involved in intracellular trafficking. We closely collaborate with cell biology groups and currently with Labex members on: role of caveolin in sphingomyelin sorting (C. Lamaze), role of myosins and actin in membrane trafficking (E. Coudrier, B.Goud), sorting and fission of the endosome membrane by the retromer complex (L.Johannes). In addition, we study fission by ESCRT-III complexes (W. Weissenhorn, Grenoble), closure of trans-cellular macroapertures (E. Lemichez, Nice), mechanics of cell filopodia (G. Tran van Nhieu, Collège de France) and the role of membrane physical properties in protein diffusion (A.Renner, ENS, Paris). Eventually, we work on the in vitro reconstitution of an action potential. Our experiments are confronted to physical models in collaboration with theory groups of the Labex (J. Prost, J.F. Joanny (I. Curie), D. Lacoste, P. Sens (ESPCI)).