Fig. 5
From: Signaling pathways have an inherent need for noise to acquire information
Noise, output range and information in gene regulation. a Schematic representation of our model of gene regulation. ka and kd correspond to the association and dissociation rate, respectively of a TF with its DNA binding site; k1 and k2 correspond to the mRNA and protein synthesis rate, respectively; d1 and d2 correspond to the mRNA and protein degradation rates, respectively. b Information, output range, and noise observed in numerical simulations of the system at different TF-DNA affinities (Keq). Information, noise, and output range are normalized by their respective maximal values. The black dotted line denote the affinity at which mutual information between signal and output is maximal. System behavior at weak (Keq = 10–9; c, d), intermediate (Keq = 10–11; e, f), and strong (Keq = 10–13; g, h) affinities. Temporal protein dynamics at three different TF concentrations are shown in c, e and g. Response distribution of the number of protein molecules for the same simulations are shown in d, f and h. The blue dashed line in c–h marks the expected mean protein value for constitutive (unregulated, always-on) expression