Vav1 serves as a GEF for Cdc42-GTPase. It interacts with and activates Cdc42. The activated Cdc42 in turn transmits its signals through the downstream target, the PAK1 kinase.
Van Aelst, L
guanyl-nucleotide exchange factor activity of p-Y142,160,174-VAV1:PIP3:CD28:GRB2 [plasma membrane]