Migration behavior of individual ARPC3^+/+ and ARPC3^−/− fibroblast cells during wound closure. (A and B) Aggregated trajectories of ARPC3^+/+ (A) and ARPC3^−/− (B) fibroblast cells migrating for 10 h toward the wound center. (C) Visual demonstration of path length vs. displacement for speed and velocity calculations. (D) Cell speed, (E) velocity, and (F) straightness of wild-type and mutant cells. Notation is as in Fig. 3 G. (G) A plot of MSD vs. time shift and (H) α values from MSD curve fits indicating more directed motion for ARPC3^+/+ cells (solid line) than for ARPC3^−/− cells (dashed line). Dotted line represents the case for α = 1 indicating pure random motion.