Table 1. Parameters associated with rates, feedback and receptor profiles along with their range of values.

The chemical rate values used in numerical analysis are scaled by the unbinding rate $r_u,{\kappa }_u$ taken to be 1. The corresponding experimental values have been taken from Lauffenburger and Linderman, 1996 where available.

Parameter	Symbol	Numerical values	Experimental values
Chemical rates
Signalling branch
Unbinding rate	r u	1	0.34 ${\text{min}}^{-1}$
Binding rate	r b	0.1–1 ${\text{nM}}^{-1}$	0.072 ${\text{nM}}^{-1}{\text{min}}^{-1}$
Degradation rate	r d	0.001–0.01	0.0022 ${\text{min}}^{-1}$
Internalisation rate	$r_I$	0.1–1	0.03–0.3 ${\text{min}}^{-1}$
Recycling rate	$r_R$	0.1–1	0.058 ${\text{min}}^{-1}$
Non-signalling branch
Unbinding rate	${\kappa }_u$	1	-
Binding rate	${\kappa }_b$	0.1–1 ${\text{nM}}^{-1}$	-
Degradation rate	${\kappa }_d$	0.001–0.01	-
Internalisation rate	${\kappa }_I$	0.1–1	-
Recycling rate	${\kappa }_R$	0.1–1	-
Conjugation rate	${\kappa }_C$	0.1–1 ${\text{nM}}^{-1}$	-
Splitting rate	${\kappa }_S$	0.1–1	-
Feedback control
Amplification	$\alpha$	$0.1-10$	-
Feedback Sensitivity	$\gamma$	$0-1$  ${\text{nM}}^{-1}$	-
Feedback strength	n	$0-5$	-
Receptor control
Signalling receptors
Hill coefficient	$a$	$0-5$	-
Minimum concentration	A 0	$50-250$ nM	-
Maximum concentration	$A_0+A_1$	$50-500$ nM	-
Position of half-maximum	A 2	$0.01-1$	-
Non-signalling receptors
Hill coefficient	$b$	$0-5$
Minimum concentration	B 0	$50-250$ nM	-
Maximum concentration	$B_0+B_1$	$50-500$ nM	-
Position of half-maximum	B 2	$0.01-1$	-
Ligand input
Maximum concentration	$A$	30 nM	-
Decay length	$\lambda$	$0.2-0.5$	-
Number of cells along $x$-direction	n x	101	-
Number of cells along $y$-direction	n y	101	-