Figure 2.
Direct visualization of erbB1 dimerization is captured by two-color SPT. (a) Sample time series showing dimer formation (white) between QD585-EGF-erbB1 (green) and QD655-EGF-erbB1 (magenta). (b) Cartoon of tracking condition (top), 3D trajectories (middle), and distance between receptors (bottom) as a function of time are shown for the indicated receptors in (a). (c) Sample time series for QD655-EGF-erbB1 and QD585-VHH-erbB1 shows interactions for a 1:2 EGF:erbB1 dimer. (d) Cartoon of tracking condition (top), 3D trajectories (middle), and distance between receptors (bottom) as a function of time are shown for the receptors in (c). Scale bar, 0.5 μm for (a) and (c). (e-h) Ensemble correlated motion plots summarize all two-color data for EGF, EGF+PD, and VHH conditions. A decrease in uncorrelated jump distance (blue) at short separations indicates that receptors are moving together. A concurrent drop in jump magnitude (red) demonstrates decreased diffusion.
