Cell density effects are propagated to downstream signal proteins. (A-B,E-F) Time-course (A,E) and dose-response analysis (B,F) for PLC-γ and Akt phosphorylation was done by treating cells as described in Figure 2. (C,G) Dose-response analysis of PLC-γ and Akt activation as a function of pY1054-VEGFR-2. Symbols and solid lines represent experimental data (symbols) and model (equations 18 and 34 in supplemental Sections 1.3 and 1.4). The receptor phosphorylation values in the x-axis are those used in Figure 2E. (D,H) Dose-response analysis of PLC-γ and Akt phosphorylation as a function of VEGF concentration. Symbols and solid lines represent experimental data and model (equations 19 and 35 in supplemental Sections 1.3 and 1.4). In all graphs, experimental values of phosphorylated PLC-γ (pPLC-γ) and phosphorylated Akt (pAkt) were obtained using vinculin and tubulin signals as normalizers, respectively. Values are the mean ± SD of 3 experiments.