VAV2 is a ubiquitously expressed structural homolog of the VAV protooncogene that is expressed preferentially in hematopoetic cells. Both proteins are comprised of a Dbl homology (DH) domain with guanosine nucleotide exchange (GEF) activity exclusively directed towards Rho/Rac GTPases, a pleckstrin homology (PH) domain, a calponin-homology (CH) region, an acidic domain (AD) a zinc finger butterfly motif, two SH3 regions and one SH2 domain. GEF activity of RhoA family G proteins is induced by tyrosine phosphorylation in wild type VAV2, and is constitutively activated in N terminus deleted oncogene forms. Constitutive expression of a VAV2 oncoprotein may result in morphological alterations including highly enlarged cells in which karyokinesis and cytokinesis frequently are uncoupled.
