Fig. 4

Total PSMAD time-course for different TGF-β concentrations. The TGF-β signalling and hence the PSMAD time-course is proportional to the TGF-β concentration. As the TGF-β input signal increases, the peak of the total PSMAD concentration is shifted to the left, is stronger and lasts longer. In the case of approximately zero TGF-β input (TGF-β=0.001), the signalling does not occur. Despite the short-term changes in the total PSMAD concentration (< 3 hours) with respect to TGF-β, its steady-state level remains the same (0.3). We have parametrize our RF- model based on its consistency with the experimental data, i.e. TGF-β=5, where the peak in the total PSMAD concentration 50-60 min after the stimulation corresponds to the short-term (transient) response and the constant level at 0.3 represents the long-term (steady-state) response of the system. Note that all concentrations are represented with arbitrary units