Figure 4

Dependence on initial values for steady-state. Plotted are steady-state values of ligand-bound receptor (R_EGF*) as a function of EGF-stimulation for different initial receptor levels R₀. For R₀ = 1.7 (orange), i.e. R₀ < CDE₀ + CIE₀, the system reaches steady-state class I independently of EGF-stimulation, as seen from R_EGF* = 0. If R₀ = 3 (green) or R₀ = 5 (black), i.e. CDE₀ + CIE₀ < R₀, the steady-state value of R_EGF becomes positive for EGF-stimulations higher than 2 (steady-state class II).