Fig. 6. The effects of Ser/Thr phosphatase inhibitors on the cytochalasin-D-induced loss of p115HEF1. (A-C) A1-F cells were plated onto FN-coated dishes, serum-starved overnight and then incubated for 4 hours with DMEM containing 0.1% heat-inactivated BSA and 2.5 ng/ml TGF-ß1 (Contr). After incubation of cells with indicated concentration of calyculin A for 0.5 hour (A), or okadaic acid for 2 hours (B), or tautomycin for 14 hours (C), the cells were treated with 2 µM cytochalasin D for 2 hours in the presence of the inhibitors. Aliquots of cell extracts containing equal amount of protein were analyzed by western blotting with anti-HEF1 pAb. Nitrocellulose membranes were stripped and reprobed with anti-actin pAb to ensure equal loading.