Integrins are transmembrane receptors for cell adhesion to the extracellular matrix. In cell migration, integrins are endocytosed from the plasma membrane or the cell surface, transported in vesicles and exocytosed actively at the cell front. In the present study, we examined the roles of VAMP3, a SNARE protein that mediates exocytosis, in cell migration and integrin trafficking. Small interfering RNA (siRNA)induced silencing of VAMP3 inhibited chemotactic cell migration by more than 60% without affecting cell proliferation. VAMP3 silencing reduced the levels of beta 1 integrin at the cell surface but had no effect on total cellular beta 1 integrin, indicating that VAMP3 is required for trafficking of beta 1 integrin to the plasma membrane. Furthermore, VAMP3 silencing diminished cell adhesion to laminin but not to fibronectin OF collagen. Taken together, these data suggest that VAMP3-dependent integrin trafficking is crucial in cell migration and cell adhesion to laminin. (C) 2009 Elsevier Inc. All rights reserved.