FIGURE 2.

Activation of the SFK subsystem. Three bifurcation diagrams indicating the relative enzyme activities at steady-state (continuous line, stable; dashed line, unstable). (A) Excitation of SFK activity. Dotted line represents a possible excitation trajectory. (B) Bifurcation curves for different values of k₂, representing allosteric effects of Ser/Thr-phosphorylation in the N-terminal SFK region. (C) Kinase activity required for overcoming Csk inhibition and triggering the SFK autophosphorylation reaction. Graphs are based on parameters in Table 2.