Abstract
The lecture presented a few more examples of the application of active gel theory to cellular phenomena, and in particular to the cortical actin layer. The cortical layer is a thin layer of cytoskeleton located beneath the cell membrane. Stresses in the direction tangential to the membrane due to molecular motors give the cell a cortical surface tension that can be calculated as a function of motor activity. If the activity of the molecular motors is not uniform along the membrane, gradients in activity (or polymerization kinetics) create cortical flows which play an important role in certain types of cell motility, and which are very similar to the Marangoni flows created by tension gradients in a membrane. The lecture also discussed the polarization of the cortical layer in a simple experiment where activity is increased locally at a point on the cell. The cell then deforms into a pear shape.
