Fig. 5. p38 MAPK is transiently phosphorylated at the leading edge. Suspended SMC were plated on fibronectin-coated coverslips for 3 hours in the presence or absence of PDGF (10 ng/ml). (A) Fixed SMC were double-labeled for F-actin and p38 MAPK. Bar, 10 µm. (B) Fixed SMC were double-labeled for F-actin and p38 MAPK or p38MAPK-P. Bar, 5 µm. These results are representative of three independent experiments.