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. 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. This protein, known as Vav, Vav1 or p95Vav, contains an N-terminal helix-loop-helix domain and a leucine zipper motif similar to that of Myc family proteins that, if deleted, causes oncogenic activation. Expression of Vav is limited exclusively to cells of hematopoietic origin, including those of the erythroid, lymphoid and myeloid lineages.
