ATTENTION : jour et salle inhabituels / unusual room and day

Much of the cell mechanics, morphology and motility is determined by the dynamical properties of an actin network moving under the action of molecular motors and by a continuous process of polymerization depolymerization called treadmilling. The actin network constitutes a physical gel the cross-links of which are both temporary and mobile. It is more complex than a physical gel in that it has a macroscopic polarity due to the microscopic polarity of actin filaments and in that the cross-links are dynamically redistributed by molecular motors. This requires an energy input, which implies that this system is intrinsically out of equilibrium. I will show how one can write down a set of phenomenological equations, which can describe this situation. I will illustrate the usefulness of the equations by considering several characteristic cases including the simple one-dimensional case, the mode structure and the behaviour of topological defects. I will illustrate how such developments provide a useful paradigm for understanding cell motility and cell dynamics.


(Séminaire de la Fédération de Physique Statistique Paris-Sud)

ESPCI and Curie Institute