Jennifer Young, University of North Carolina


The Physics of Bleb Formation: A fluid-structure interaction model

Abstract: Eukaryotic cells are composed of organelles, cytoplasm, a cytoskeleton and an encasing plasma membrane. These structures interact to produce movement and shape change in the cell. A "bleb" is a balloon-like protrusion of the plasma membrane that forms when the membrane separates from the underlying cytoskeletal network of actin filaments, and is pushed outward by flowing cytoplasm. Blebs are one of a number of cell motility mechanisms and they also play a key role in the break-up of a cell during apoptosis (cell death). The physics behind bleb formation is not yet clearly understood. Here we propose a mathematical model to support the theory that once the membrane and cytoskeleton have separated, the creation of blebs is driven by pressure gradients in flowing cytoplasm. The model includes the motion of the actin filaments, the plasma membrane and the cytoplasm. This system of PDEÕs is solved using a wave propagation method and a finite volume scheme, both implemented with a software package known as BEARCLAW.

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