Control of ERK activation by cell contact surfaces.

(A) Nuclear dpERK immunofluorescence (IF) signals in the a6.5, a6.6, a6.7 and a6.8 cell types as measured in IF experiments (left) and computed with the model (right, Erkf values). Each point represents a single cell and modeling results are computed using the measured values of S1. Means and standard deviations are shown in black. A = 1850 and B = 155.11 in Eq (14). (B) Nuclear dpERK IF signals in individual a-line cells are shown as a function of the relative area of cell surface contact with A-line cells in experiments and in the model. Experimental data are shown in grey (a6.8 cell type), green (a6.6 cell type), blue (a6.7 cell type), magenta (a6.5 cell type), predictions of the model in black. Hill coefficient obtained by fitting the model predictions with a Hill function: 2.41. A = 3000 and B = 324.52 in Eq (14). The area shaded in grey represents the uncertainty on the model prediction. (C) Injected/control ratios of nuclear dpERK signal in dnFGFR half-injected embryos (on the left) and in Eph3ΔC half-injected embryos (on the right). Left and right columns show experimental dpERK IF and computed Erkf ratios, respectively. Injection of dnFGFR and Eph3ΔC were modeled by considering RT = 100 and QT = 10, respectively. A = 1850 and B = 155.11 in Eq (14).