Vav proteins belong to the Dbl family of guanine nucleotide exchange factors (GEFs) for Rho/Rac small GTPases. The three identified mammalian VAV proteins (VAV1, VAV2 and VAV3) differ in their expression. Vav1 is expressed only in hematopoietic cells and is involved in the formation of the immune synapse. VAV2 and VAV3 are more ubiquitously expressed. VAV proteins contain the Dbl homology domain, which confers GEF activity, as well as protein interaction domains that allow them to function in pathways regulating actin cytoskeleton organization.
