TABLE 1.

Velocity and persistence of migrating NRK cells^a

Transfection	Velocity (mean ± SD)	Velocity difference versus Luc	Persistence (mean ± SD)	Persistence difference versus Luc
siLuc	0.854 ± 0.168		0.687 ± 0.106
siRalA	0.792 ± 0.175	− (P = 0.32)	0.686 ± 0.090	− (P = 0.97)
siRalB	0.588 ± 0.155	+++ (P < 0.0001)	0.667 ± 0.121	− (P = 0.59)

^aMonolayers of control cells (transfected with a siRNA against luciferase [siLuc]) or cells depleted of RalA or RalB by siRNA (siRalA or siRalB) were wounded and filmed during 24 h, starting 1 h after the wound. Cells were tracked on films using MetaMorph and analyzed for speed and persistence; persistence was calculated as the distance between a starting point and an arrival point divided by the length of the path followed between these two points. The calculation in the table results from data collected by tracking at least 25 cells in each case. The only and extremely (P < 0.0001) significant difference observed was the decrease in velocity of cells depleted of RalB. This difference was reproduced in two other filmed experiments. Velocity is given in micrometers per minute.