(a) Simplified cartoon model of IL-27/HypIL-6 signal propagation layers and coverage of the mathematical modeling approach. (b) Model selection results showing the relative probabilities of each hypothesis, for different values of the distance threshold, , in RPE1 cells. (c) Pointwise median and 95% credible intervals of the predictions from the mathematical model, calibrated with the experimental data, using the posterior distributions for the parameters from the ABC-SMC. For the experimental data, phosphorylation kinetics of pSTAT1 and pSTAT3 were followed in RPE1 IL-27Rα after stimulation with saturating concentrations of IL-27 (2 nM) and HypIL-6 (10 nM). (d) Kernel density estimates of the posterior distributions for the parameters in the mathematical models where and . A '+' in the parameter notation indicates that this is a forward rate constant (binding) and a '–' in the notation indicates that this is a reverse rate constant (dissociation). In the first row, a '6' in the notation indicates that this is a reaction rate in the HypIL-6 system and a '27' indicates that this is a reaction rate in the IL-27 system.