ITP South Building 6520

In this talk, I will discuss membrane deformations powered by a point force under the condition of high pressure and low tension, which is rarely studied but directly relevant for endocytosis in yeast cells with a cell wall. I will show that the force-height relationship of membrane deformations under this condition is drastically different from that under conditions of high tension and low pressure. In addition, the boundary conditions at the attachment points of the membrane with the cell wall have dramatic effects on the force-height relationship. In particular, if the membrane is allowed to freely rotate at the attachment points, proteins that induced membrane curvature can lift the membrane off the cell wall without any external forces. This result is in sharp contrast with the conclusion of a previous study which adopted boundary conditions that fix the angle between the membrane and the cell wall at the attachment points. I will also discuss possible ways to pull the membrane off the cell wall against the high osmotic pressure with a small amount of force that can be provided by actin polymerization.