Table 3. Values of chemical rates and feedback parameters obtained after optimising the two-tier two-branch channel with inter-branch feedback on the internalisation rate ${\kappa }_I$ of the non-signalling branch, keeping the receptor profiles spatially uniform, with and without uncorrelated noise.

The optimised values of the chemical rates quoted below are scaled by the unbinding rate r_u, ${\kappa }_u$ taken to be 1.

Parameter (Symbol)	Optimised value
	uniform receptor profiles	uniform receptor profiles with uncorrelated noise
Chemical rates
Signalling branch
Binding rate ($r_b,{\text{nM}}^{-1}$)	0.0922	0.0782
Degradation rate in tier 1 ($r_d^{(1)}$)	0.0089	0.0041
Degradation rate in tier 2 ($r_d^{(2)}$)	0.0092	0.0095
Internalisation rate ($r_I$)	0.0225	0.0611
Recycling rate ($r_R$)	0.0403	0.0971
Non-signalling branch
Binding rate (${\kappa }_b,{\text{nM}}^{-1}$)	0.0464	0.0265
Degradation rate in tier 1 (${\kappa }_d^{(1)}$)	0.0035	0.0045
Degradation rate in tier 2 (${\kappa }_d^{(2)}$)	0.0071	0.0068
Internalisation rate (${\kappa }_I$)	0.02	0.0513
Recycling rate (${\kappa }_R$)	0.0989	0.0770
Conjugation rate (${\kappa }_C,{\text{nM}}^{-1}$)	0.7605	0.7579
Splitting rate (${\kappa }_S$)	0.7038	0.3036
Feedback control
Amplification ($\alpha$)	-	-
Feedback Sensitivity ($\gamma$)	0.0939	0.1946
Feedback strength ($n$)	4.6310	0.6202
Tier-wise weights
weight of tier 1 (w1)	0.0046	0.2875
weight of tier 2 (w2)	0.9954	0.7125