Effect of peptide D on RSMC migration into a wound. Single-cross wounds were made in confluent monolayers grown on glass coverslip. After a wash with PBS, monolayers were then allowed to recover for 24 hours in the absence or in the presence of 1 pmol/L peptide D. Peptide D contains the minimum chemotactic epitope of rat u-PAR, corresponding to the human peptide 1. One percent FCS was used as a positive control. Quantification of migration was performed by taking photographs at low magnification and counting cells that had migrated into the cell-free space (A). Two examples of actin cytoskeleton organization in migrating cells, visualized using rhodamine-conjugated phalloidin, are shown in (B) and (C).