β3 integrin is required for p130Cas SD tyrosine phosphorylation and formation of the p130Cas–CrkII complex. (A) p130Cas SD tyrosine phosphorylation in siRNA-transfected cells. Left, representative immunoblot (BE); right, quantitation (mean + SEM; n = 5). *, P < 0.05; **, P < 0.01; unpaired Student's t test. Closed bars, BE; open bars, MDA-MB-231; shaded bars, SNB19. Irrelevant lanes were removed (represented by vertical black lines). (B) Analysis of p130Cas–Crk complexes. Left, representative immunoblots (BE); right, quantitation (mean + SEM; n = 4). *, P < 0.05; unpaired Student's t test. Closed bars, BE; open bars, MDA-MB-231; shaded bars, SNB19. (C) Analysis of p130Cas SD tyrosine phosphorylation in HEK 293T cells transfected with siRNAs and uPAR or empty vector was performed as described in Fig. 3 (mean + SEM; n = 4). *, P < 0.05; unpaired Student's t test. Immunoblots showing knockdown are in Fig. S2 E.
