Fig. 5.
Predictions from the RECI model and parameter sensitivity analysis. (A) Calculated concentrations of Smad species in the nucleus and cytoplasm during TGF-β stimulation. Concentrations given refer to the sum of Smad2 and EGFP-Smad2. (B) As an input function, receptor activity was changed according to a double step function (blue line). The effect on the nuclear concentration of Smad2/Smad4 complexes (red line) was calculated. (C) As in B, except receptor activity is represented by a step function with added rapid fluctuations. (D) Sensitivity analysis. Scaled sensitivity coefficients for the plateau concentration of nuclear Smad2/Smad4 complexes to variations in the individual reaction rates are given. CIF, complex import factor for the respective complex (defined as import rate of Smad complexes over the import rate of monomeric Smads, see SI Text).