Figure 4.

Impact of kinetic parameters on the type of the TGF-β response. (A, C) A strong negative feedback, fast nuclear shuttling of Smads and a rapid dissociation of the dimers favour a transient (green) over a sustained response (red). (B, D) Fast production and degradation of the I-Smad mRNA and I-Smad protein is required for oscillations to appear, and a low TGF-β receptor on-rate enhances oscillatory (blue and magenta in the scatter plot, and black to blue in the contour plot) relative to a transient (green in the scatter plot, and green to yellow in the contour plot) response.