We report that Binder of Arl Two (BART) plays a role in inhibiting cell invasion 
by regulating the activity of the Rho small guanosine triphosphatase protein 
Rac1 in pancreatic cancer cells. BART was originally identified as a binding 
partner of ADP-ribosylation factor-like 2, a small G protein implicated as a 
regulator of microtubule dynamics and folding. BART interacts with active forms 
of Rac1, and the BART-Rac1 complex localizes at the leading edges of migrating 
cancer cells. Suppression of BART increases active Rac1, thereby increasing cell 
invasion. Treatment of pancreatic cancer cells in which BART is stably knocked 
down with a Rac1 inhibitor decreases invasiveness. Thus, BART-dependent 
inhibition of cell invasion is likely associated with decreased active Rac1. 
Suppression of BART induces membrane ruffling and lamellipodial protrusion and 
increases peripheral actin structures in membrane ruffles at the edges of 
lamellipodia. The Rac1 inhibitor inhibits the lamellipodia formation that is 
stimulated by suppression of BART. Our results imply that BART regulates 
actin-cytoskeleton rearrangements at membrane ruffles through modulation of the 
activity of Rac1, which, in turn, inhibits pancreatic cancer cell invasion.