Chemotaxis of ARPC3^+/+ and ARPC3^−/− fibroblast cells in response to an EGF gradient. The ARPC3^+/+ and ARPC3^−/− cells were plated on fibronectin-coated μ-Slide and analyzed for 12 h in the presence of EGF gradient (500 ng/ml at source). (A and B) Aggregated trajectories of individual ARPC3^+/+ (A) and ARPC3^−/− (B) cells in the presence of the EGF gradient. (C) Cell speed, (D) velocity, (E) straightness, and (F) MSD α values for wild-type and mutant cells presented as in Fig. 4. The data came from tracking of 43 (two experiments) ARPC3^+/+ and 115 (five experiments) ARPC3^−/− cells.