Three-Dimensional Cytoplasmic Calcium Propagation With Boundaries

Ca2+ plays an important role in cell signal transduction. Its intracellular propagation is the most basic process of Ca2+ signaling, such as calcium wave and double messenger system. In this work, with both numerical simulation and mean field ansatz, the three-dimensional probability distribution of Ca2+, which is read out by phosphorylation, is studied in two scenarios with boundaries. The coverage of distribution of Ca2+ is found at an order of magnitude of mu m, which is consistent with experimental observed calcium spike and wave. Our results suggest that the double messenger system may occur in the ER-PM junction to acquire great efficiency. The buffer effect of kinase is also discussed by calculating the average position of phosphorylations and free Ca2+. The results are helpful to understand the mechanism of Ca2+ signaling.