Before revision:  Many existing mathematical models of cell polarization are formulated in  one or two spatial dimensions and hence cannot accurately capture the effect of cell shape, as well as the response of the cell to signals from different directions in a three-dimensional environment. To study those effects , we introduce a three-dimensional reaction-diffusion model of a cell.
After revision:  Many existing mathematical models of cell polarization are formulated in one or two spatial dimensions . In this paper , we introduce a three-dimensional reaction-diffusion model of a cell.