Fig. 5. Treatment of cells with uPAR ligand causes enhanced localization of caveolin PY14 to areas of cell-matrix contact. (A) Fibroblasts were seeded onto glass coverslips coated with 10 µg/ml fibronectin for 2 hours. Cells were then treated with 50 µM P25 or the control peptide, S25, for 1 hour. Cells were fixed, permeabilized and immunostained for caveolin PY14 and the β1 integrin. (B) Confluent monolayers of A1-F cells were incubated with 50 µM S25 or P25 for 1 hour. SAM was isolated by removing cells from the substrate with EGTA and was solubilized in sample buffer under reducing conditions. SAMs were electrophoresed and western blotted. Blots were cut and stained for caveolin PY14, EGFR and paxillin.