Formation of lamellipodia is the first step during cell migration, and involves actin reassembly at the leading edge of migrating cells through the membrane transport of WAVE2. However the factors that, regulate WAVE2 transport to the cell periphery for initiating lamellipodia formation have not been elucidated. We report here that in human breast cancer MDA-MB-231 cells, the hepatocyte growth factor (HGF) induced the association between the constitutive complex of beta PIX and GIT1 with WAVE2 which, was concomitant with the induction of lamellipodia formation and WAVE2 transport. Although depletion of beta PIX by RNA interference abrogated the HGF-induced WAVE2 transport and lamellipodia formation, GIT1 depletion caused HGF-independent WAVE2 transport and lamellipodia formation. Collectively, we suggest that beta PIX releases cells from the GIT1-mediated suppression of HGF-independent responses and recruits GIT1 to WAVE2, thereby facilitating HGF-induced WAVE2 transport and lamellipodia formation. (C) 2009 Elsevier Inc. All rights reserved.