Spherical cells can support gradients along the source/sink axis.A) Schematic of a spherical cell of radius rswith oppositely localized kinase and phosphatase spread over a spherical cap. B) 3D mathematical modeling of the distribution of [R ∼ P] in a spherical cell with radius rs = 0.4 μm. C) [R ∼ P] line scan through the cell middle showing average volume-weighted density along the cell length (along the dashed line in A) for different radii rs. D) Schematic of 1D distributions of kinase and phosphatase activities that produce profiles mimicking those in (C) for rs> 0.5 μm, with background kinase and phosphatase activities localized from the middle of the cell to the phosphatase pole and kinase pole, respectively, and overlapping by L/20.
Tropini et al. BMC Biophysics 2012 5:17 doi:10.1186/2046-1682-5-17