WB (peptide competition) analysis of Cos7 cells over-expressing murine Vav3 were serum starved and left treated (Lane 1) or treated (Lane 2-5) with EGF using GTX24764 VAV3 (phospho Tyr173) antibody prior incubated with the non-phospho immunogen (Lane 3), a generic (pY) peptide (Lane 4), or, the phosphopeptide immunogen (Lane 5) control. The data show that only the immunogen phosphopeptide blocks the signal, demonstrating the specificity of the antibody.