Vav2 is an oncoprotein member of the Dbl family of proteins that serves as a guanine nucleotide exchange factor (GEF) for the Rho family of Ras-related GTPases (1). Vav2 possesses a C-terminal pleckstrin homology (PH) domain and a tandem Dbl homology (DH) domain which interacts with Rho family GTPases to catalyze GDP release (1-2). The PH domain serves as a negative regulator of DH domain GEF activity, which is promoted by phosphatidylinositol 4, 5-phosphate (PIP2) and is antagonized by the PI3K product, phosphatidylinositol3, 4, 5-phosphate (PIP3) (3). Hence, PI3K may facilitate the activation of Vav. Vav2 also contains a cysteine-rich domain (CRD) that is a positive modulator for DH domain function (4). Vav2 is widely expressed in human tissues (5-6). The SH2 domain of Vav2 associates with the receptor tyrosine kinases EGFr (7-9) and PDGFr (8), binding preferentially to the phosphorylated residues pTyr-992 and pTyr-1148 of EGFr (10) and directly to multiple autophosphorylation sites of PDGFr (8). Overexpression of Vav2 has been shown to be sufficient to activate its oncogenic potential (6). In ovarian tumor cells, the binding of hyaluronan to its receptor (CD44v3) and the recruitment of Grb2 and p185HER2 to the CD44v3-Vav2 complex activates Vav2-mediated Rac1 and Ras signaling, leading to ovarian tumor cell migration and growth. Domain Information: Calponin homology domain, PH domain, Phorbol esters/diacylglycerol binding domain (C1 domain), RhoGEF domain, Src homology 2 domains, Src homology 3 domains Gene Ontology Terms: guanyl-nucleotide exchange factor activity, intracellular signaling cascade, diacylglycerol binding Application(s): Peptide ELISA: antibody detection limit dilution >1:32,000. Western Blot: Approx 100kD band observed in 293 lysate (predicted MW of 100kD according to NP_003362). Recommended for use at 1-1.5ug/ml. Staining (1.5ug/ml) of 293 lysate (RIPA buffer, 30ug total protein per lane). Primary incubated for 1 hour. Detected by western blot using chemiluminescence. Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20C. Aliquots are stable for 12 months after receipt. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Peptide Blocking: Corresponding peptide is available for Peptide Blocking studies. See V2121-11A-P. Antibody is typically 0.5mg/ml and peptide is supplied as a 100ul pellet. When peptide is reconstituted in 200ul water, the concentration would also be 0.5mg/ml. To start, the best ratio would be 1:1 (molar excess of peptide relative to antibody when identical volumes are mixed). Mix equal volumes of peptide and antibody at the required dilution and leave at ambient temperature. It is best is to have two identical blots to be incubated with equal amount of antibody, but one with the antibody pre-adsorbed to the peptide for 20min. Then incubate and develop the two blots in parallel.
