Variations of key parameters in the two-state protein model, with kinases and phosphatases as discrete mediators. Columns correspond to simulations using (A-D) parameter values of Figure 11; (E-H) k
3= 0.01. Rows correspond to single-cell time courses of (A, E) P and (C, G) P
; and the mean of a population of 50 cells of (B, F) P and (D, H) P
. Trajectories portray SSA simulations (blue), and input kinase signal (red).