Characterization of the mobility states of EGFR.
(A) Classified tracks of Cy3-SNAP-EGFR. The track segments are color-coded according to their mobility state (blue: free; green: confined; red: immobile). Shown is a 5×5 μm region of interest in an MCF-7 cell after 10 minutes of stimulation with 16 nM EGF (see also S4 Fig). (B) MSD analysis by state, after 10 minutes of stimulation with 16 nM EGF. The linear curves (blue symbols) are typical for Brownian motion, indicating free diffusion on this time-scale. The green symbols show a flattening of the curve due to confinement of the particles within a limited area. The red symbols show only minor displacement on this time-scale, indicating that the particles are immobile. Lines: linear fits to the beginning of each curve. Legend: fitted diffusion coefficients (D, μm2s-1). Error bars denote SEM.
