VAV family members are cytoplasmic guanine nucleotide exchange factors (GEFs) for Rho-family GTPases (RAC, RHO and CDC42). VAV1 is found predominantly in hematopoietic cells, whereas VAV2 and VAV3 are more broadly expressed. VAV proteins link the cell surface receptors like FCGR to the intracellular Rho GTPases and the actin cytoskeleton during phagocytosis (Hall et al 2006). Experiments using two-hybrid system suggest that VAV1 with its SH2 domain directly binds to the phosphorylated Y342 of SYK (Deckert et al. 1996). VAV proteins are also recruited to membrane through their PH domain by binding PI(3,4,5)P3 produced by PI3K.