Actin filaments differentially regulate EphA4 activation at the plasma membrane. (A) Representative images of ECFP/FRET emission ratios for the KRas-EphA4 biosensor and the Lyn-EphA4 biosensor in cytochalasin D (cytoD) pretreated MEF cells before and after ephrinA3 stimulation (100× objective lens, scale bar, 10 μm). (B) Time courses of normalized ECFP/FRET emission ratios (mean ± SEM) for the KRas-EphA4 biosensor (green line, n = 10, N = 3) and the Lyn-EphA4 biosensor (red line, n = 6, N = 3) before and after ephrinA3 stimulation in CytoD pretreated MEF cells. “n” means the total cell number. “N” means the number of individual experiment repeats.