糖心TV

Mechano-sensing through self assembly at the cell membrane: the example of caveolae

Professor Pierre Sens, Institute Curie

Abstract: Mechano-sensing at the cell membrane often involves change of conformation of proteins under stress, such as the opening of mechanically-gated channels or the unfolding adhesion proteins. Another class of mechano-sensing systems relies the assembly and disassembly of multi-protein complexes. In this talk, I will discuss the case of caveoale, small invaginated nanodomains at the plasma membrane of many cell types, that have been classically involved in membrane trafficking and signalling. After presenting experimental evidence - obtained by collaborators - of the role of caveolae mechanics in the control of different signalling pathway, I will describe a thermodynamic model of caveolae stability under tension based on the phase separation of membrane-associated proteins into invaginated, multi-component membrane domains. I will in particular discuss the importance of the multi-component nature of caveolae, enriched in the curvature-generating membrane protein caveolin, and stabilised by the curvature-dependent binding of cytosolic proteins, including cavin which can form a rigid coat over the caveolin domains, and the ATPase EHD2 which can form ring-like oligomers at the caveolae neck. If time permits, I will discuss the consequence of caveolae mechano-signalling on cell polarity and directional migration.

Biography: Pierre Sens is research director at CNRS and group leader at Institut Curie, in Paris. Pierre received his PhD from the University of Strasbourg (France) in the field of soft condensed matter and complex fluids. He then moved to U.C. Santa Barbara for a couple of years, then to Institut Weizmann in Israel for a year, before coming back to France with the CNRS. Pierre is a theoretical physicist applying physical concepts to the study of biological systems, in particular to living cells. He investigates the active mechanics of cells, with a focus on cell motility and mechano-sensation. Pierre also work on the physical basis of cellular homeostasis such as cell volume and density regulation. Pierre also studies the physical principles of intracellular organisation, in particular the generation and maintenance of cellular organelles, and the physics of cellular membranes, particularly membrane shaping by proteins and the cytoskeleton.