Figure 1.

The MEK/ERK System and Modeling of the MEK/ERK Module

The binding of a growth factor to its receptor activates a succession of reactions that lead to the phosphorylation of MEK; active MEK, in turn, phosphorylates ERK. In this study, we focus on the MEK/ERK module (circled in red). The impact of the stimulus and the upstream reactions on the evolution of the concentration of active MEK are modeled using a time-dependent function, which depends on three parameters (k₁, k₁₀, and T). In addition, active MEK is degraded with rate k₂. The detailed mechanism of phosphorylation and dephosphorylation of ERK is represented in the bottom-right part of the figure. Pt denotes the cognate ERK phosphatase. The reaction rates are shown next to their associated reactions.