uPAR expression drives p130Cas SD phosphorylation and formation of the p130Cas–CrkII complex. (A) p130Cas SD tyrosine phosphorylation in uPAR- or vector-transfected (Vec) HEK 293T cells. Left, representative immunoblots; right, quantitation of SD phosphorylation (mean + SEM; n = 3). (B) p130Cas–Crk complex formation in uPAR- or empty vector–transfected HEK 293T cells. Left, representative immunoblots; right, immunoblot showing expression of p130Cas, uPAR, and GAPDH. (C) p130Cas SD tyrosine phosphorylation in siRNA-transfected cells. Top left, representative immunoblots (BE); top right, uPAR immunoblotting; bottom, quantitation. Closed bars, BE; open bars, MDA-MB-231; shaded bars, SNB19 cells (mean + SEM; n = 4). *, P < 0.05; **, P < 0.01; unpaired Student's t test. (D) Analysis of p130Cas–Crk complex formation. Left, representative immunoblots (BE); right, quantitation. Closed bars, BE cells; open bars, MDA-MB-231 cells; shaded bars, SNB19 cells (mean + SEM; n ≥ 4). *, P < 0.05; **, P < 0.01; unpaired Student's t test.