CeNS Colloquium

Prof. Pierre Sens
Laboratoire de Physico-Chimie Théorique, ESPCI, Paris

Biological cells are able to cope with mechanical perturbations from the outside world, such as osmotic shocks. Cells are also able to generate mechanical stress that allows for shape changes and motility. Many of the mechanisms allowing this versatile behaviour occur at the cell interface, and involve physical interactions between the cell membrane and the underlying cytoskeleton, the meshwork of biopolymer and molecular motors able to convert chemical energy into mechanical forces. In this talk, I will describe our theoretical and experimental efforts to understand membrane cytoskeleton interaction from the study of cellular blebs. Blebs are micron-size spherical membrane blisters transiently appearing at the plasma membrane following membrane detachment from the cytoskeleton, and retracting after cytoskeleton rejuvenation. Blebs are actively generated by some cells and can be harnessed for motility. I will describe a combination of theoretical modeling and experimental observations that illustrate the dynamical nature of membrane-cytoskeleton interactions. We will observe the motion of Entamoeba histolytic cells, which exhibits motility through membrane blebbing, in the constrained environment of a micropipette. We will see that the variety of cellular response to this controlled mechanical perturbation, including remarkable spontaneous oscillations, can be explained using physical modeling.