Fig. 2. PIE-FCCS investigation of the homomeric interactions of EGFR and EphA2.

(A) Self-assembly of EGFR was studied under various conditions. PIE-FCCS data were recorded, and the resulting f_c values are reported before treatment (white), after the addition of EGF (gray), after treatment with the PLC inhibitor U73122 (blue), and after treatment with the PLC activator 3M3FBS (green). (B) Diffusion coefficients for EGFR are shown for each treatment condition. (C) Epifluorescence images of EGFR expressing COS-7 cells without (top) and with (bottom) EGF ligand treatment. (D) Homomultimerization state of EphA2 was recorded under the same treatments except the ligand treatment was with EA1. (E) Diffusion coefficients are shown for EphA2 under each treatment condition. (F) Epifluorescence images of EphA2 expressing COS-7 cells are shown without (top) and with (bottom) EA1 ligand treatment. In the box-and-whiskers plots, the whiskers indicate the maximum and minimum values; the box indicates the 25th to 75th percentile, and the line is the median value (median value shown as text). We performed one-way analysis of variance (ANOVA) tests with uncorrected Fisher’s least significant difference (LSD) post hoc tests to obtain adjusted and individual P values (*P < 0.0367, **P < 0.0034, and ****P < 0.0001). Diffusion coefficient data are represented as mean values ± SEM. NS, not significant.