Simulation results from Ras and B-Raf mutation models: (A) Ras and B-Raf Mutations: The red and blue lines represent the simulated levels of active ERK over 60 minutes with a B-Raf and Ras mutation, respectively; as both lines are so similar, the red line obscures the blue line from view for the most part. As can be seen, both Ras and B-Raf mutations result in the constitutive activation of ERK to very high levels, as expected. (B) Raf Plots: Both the lines on this graph come from the Ras mutation model. The red and blue lines represent the simulated levels of active Raf-1 and B-Raf, respectively. As can be seen, the Ras mutation results in the sustained activation of B-Raf to very high levels, but the activation of Raf-1 is more transient and begins to decline due to the Ras/PI3K/Akt feed-forward loop.