Adaptation via negative feedback

Bhalla and Iyengar introduced a feedback loop in the MAPK module, where activated MAPK phosphorylates mono-phosphorylated MAPKKK (see Fig. 1), which is inactivated in the double phosphorylated form. This reaction is very slow in their model and when we increase the speed of this reaction, the cascade shows damped oscillations (see Fig. 5).

Figure 5: Damped oscillations after including a negative feedback loop. Increasing stimulus leeds to increasing amplitute. The system relaxes to a very low steady-state.