(A) BT549 cells were transfected with plasmids encoding WT GFP-BCAR3, R171V GFP-BCAR3, L744E/R748E GFP-BCAR3 or R171V/L744E/R748E GFP-BCAR3. Cells were incubated for 24 hours prior to plating on 10μg/ml fibronectin-coated coverslips for 4 hours. Cells were fixed, stained with polyclonal Cas antibodies (panels b, e, h, k), and subjected to TIRF microscopy to visualize adhesions. Merged images are shown in the right panels and insets show higher magnifications of the designated areas. (B) BT549 cells were transfected with plasmids encoding GFP, WT GFP-BCAR3, R171V GFP-BCAR3, L744E/R748E GFP-BCAR3 or R171V/L744E/R748E GFP-BCAR3 and lysed in a non-denaturing buffer 24 hours post-transfection. Total cell protein and Cas immune complexes (generated from 50X more protein than the lysates) were immunoblotted with antibodies to detect the indicated proteins. Left and right panels are identical exposures from the same film.