2009-05-06
9:00 at HCI J 574

Out-of-Equilibrium phase separation in Biological Membrane

Pierre Sens

ESPCI Paris

Spatial heterogeneity is often crucial to the proper function of biological membranes. Phase separation of lipids and membrane protein is for instance thought to be needed for biochemical signaling across the plasma membrane, or for the formation of protein-coated vesicles involved in cellular transport. Experimental evidences suggest that these dynamical processes are regulated, possibly by flux of membrane material, or through the activity of energy-consuming proteins. I will present theoretical investigations of situations where phase separation is maintained out-of-equilibirum by active processes. I will discuss the formation of membrane domains under continuous recycling of membrane material, and the formation of coated vesicles when the lifetime of the coat components at the membrane is controlled by the activity of a GTPase. In both situations, the stationary state of the membrane is shown to be tightly controlled by the dynamics of recycling, giving rise to non-linear phenomena (dynamical switches) possibly relevant to the biological function of the membrane.