Figure 5
From: The formation of acetylcholine receptor clusters visualized with quantum dots
AChR movement during the formation of bead-induced clusters. (a-c) Instantaneous velocity plots of single BBQs at or away from a bead-induced AChR cluster. (a) Movement of a receptor at bead-muscle contact and its trapping at the 60 sec. The red line shows the mean velocity before and after trapping. (a') Additional examples of BBQ trapping. Only mean velocities of individual BBQs are shown. Color solid lines: BBQs underneath beads; black dashed lines: BBQs at the rim of beads. (b) Example of a freely moving BBQ at bead-muscle contact. (c) A freely moving receptor outside bead contact. (d-f) Schematic representation of immobile (black dots) and mobile (white dots) BBQs at a single bead-induced AChR cluster at 2, 4 and 24 hr after bead addition, showing increasing number of immobile receptors. (g) Immobility of BBQs at a pre-patterned cluster, in contrast to mobile ones outside the cluster area (h). (i) Quantification of receptor mobility based on diffusion coefficient measurements. Receptors with D less than 10-11 cm2/s are designated immobile and those with D above this value are considered mobile. BBQs outside bead-muscle contact were also tracked 4 hr after bead addition ("outside 4 hr"). (j) Diffusion coefficients of mobile BBQs at various distance away from bead-muscle contacts (mean ± sem; number of tracks analyzed: 19, 11 and 21 from near to far).