Figure 4
The circuit response to input signals from Grb2 and Gab1.
(a) Two-parameter bifurcation phase diagram. Two input signals Grb2 (x-axis) and Gab1 (y-axis) are selected as the two control parameters. As explained in the text, each phase corresponds to a different combination of coexisting phenotypes (Phase plane diagrams for each phase are shown in Supplementary Fig. S5). For example, the orange area is the phase {M, A/M}, which means that cells in this phase can belong to either the M or the A/M phenotype. The colors used for different phases are explained by the legend in Fig. 3. (b) One-parameter bifurcation diagram for the circuit driven by Gab1 when the Grb2 level is fixed to be 8 × 105 molecules. The corresponding trajectory in the two-parameter bifurcation phase diagram (Fig. 4a) is shown by a purple line. The transitions between the M and A/M phenotypes are illustrated by the dashed upward and downward arrows. (c) One-parameter bifurcation diagram for the circuit driven by Grb2 when the Gab1 level is fixed to be 2.5 × 105 molecules. The corresponding trajectory in the two-parameter bifurcation phase diagram (Fig. 4a) is shown as a brown line. The transitions between the A and A/M phenotypes are illustrated by the upward and downward arrows.
