Figure 2. MAPK pathway signaling plasticity.
A. Upon upstream activation, RAS becomes activated, resulting in signal transduction through RAF, MEK and ERK. The MAPK pathway can turn itself off via negative feedback loops at multiple nodes to prevent hyperactivity. Inhibitory function shown as red arrows; activating functions are shown as black arrows. B. Characterized oncogenic mutations in the MAPK pathway are shown in yellow. C. A simplified schema of adaptive MAPK signaling following pathway inhibition.