Fig. 3. Average migration speed in response to inhibition of stretch-activated Ca²⁺ entry and Ca²⁺ depletion. NIH3T3 cells incubated globally in gadolinium ion showed a marked decrease in average migration speed compared with control cells. Cell migration speed also decreased sharply upon application of Gd³⁺ to the leading edge, but not when applied to the trailing edge. Global application of EGTA similarly caused a sharp decrease in average migration speed. The rate measured in 5 mM EGTA included some component of nuclear displacement as a result of limited cell retraction. Error bars indicate standard error of the mean.