Reduced Rac activation (bottom) leads to more persistent migration.
The small GTPases Rac and Rho modulate migration speed and chemotaxis, with increased expression of Rac in lamellipodia correlating with increased velocity. In the current study, Pankov et al. found that reducing the total amount of Rac1 in a cell by 30% to 50% induced persistent movement and limited random walking. The reduction in Rac reduced the number of lamellae, leaving such structures only at the cell ends. By contrast, knocking down RhoA reduced the rate of migration but did not alter migration style.
Unlike chemotaxis, which also induces persistent movement, the newly identified Rac function did not require phosphatidylinositol 3′ kinase activity, indicating that the two methods of migration control...
