Fig. 3. PTP-PEST reintroduced into PTP-PEST^–/– cells inhibits spreading through paxillin. (A) Immunofluorescence staining of PTP-PEST^–/– cells transfected with GFP, GFP and PTP-PEST, PTP-PEST and paxillin, or PTP-PEST and paxillin C523S and plated on fibronectin-coated coverslips for 60 minutes. Cells were co-stained with rhodamine-phalloidin to visualize the actin cytoskeleton. Bar, 25 µm. (B) Inhibition of spreading was measured as the percentage of round GFP-positive cells observed in A. A minimum of 100 cells were counted per condition in three independent experiments. Results show the mean±s.d. **P<0.001, *P<0.05. (C) Western blots of transfected cells were probed for anti-paxillin and anti-PTP-PEST antibodies to demonstrate equal expression of constructs.