Fig. 2.

Model schematic. A pair of interacting cells, i and i+1, is shown; longer cell arrays are simulated by adding similar modular cells to the array. The inductive signal I_i activates MPK-1 in each cell i with rate constant . Constitutive phosphatases Ph deactivate MPK-1^* with rate constant . The inductive signal up-regulates the lateral signal in the neighboring cell with rate constant k_x3 and down-regulates it in the same cell with rate constant k_x2. In turn, the lateral signal in each cell deactivates MPK-1^* with rate constant k_x1.