Models for NGF-induced Erk1/2 signalling with two subpopulations which have different TrkA levels.

<p>(A) Schematic of model for NGF-induced Erk1/2 signalling. Arrows represent conversion reactions and regulatory interactions. The frequency of an object is used to illustrate its abundance. (B) Mean and standard deviation of measured pErk levels (kinetic: , 18797 cells; dose response: , 12205 cells) as well as simulated mean for the models and . (C) Histograms of the measured pErk levels (data of biological replica are pooled) and corresponding distributions computed using model and . Simulation results for and are very similar leading to significant overplotting. pErk levels in (B) and (C) are in arbitrary units of intensity (UI). (D) Maximum likelihood estimates of parameters and confidence intervals for the parameters of and . Vertical lines mark the maximum likelihood estimates and the horizontal bars represent the confidence intervals corresponding to different confidence levels (80%, 90%, 95% and 99%) computed using profile likelihoods.