Effects of PKCι pseudosubstrate inhibitor peptide on cell motility. A. U87MG cells were treated with 20 or 50 μM atypical PKC pseudosubstrate peptide inhibitor (PSI) for 2 h. Whole cell lysates were then analyzed for levels of phosphorylated PKCι and total PKCι by Western blotting. B. Migration distance per minute (um/min) was quantitated using Ziess LSM image browser software. Bar graphs show the mean +/- SD from three independent videomicroscopy experiments each for control and PS-I treated U87MG cells (mean of 10 cells quantified per experiment). C. Quantitation of leading edge formation from videomicroscopy. Cells from three independent movies were analyzed for the formation of a single dominant leading edge. Bar graphs show the mean +/- SD. D. Representative examples comparing cell motility in control cells and cells treated with 20 μM PS-I. Still images from videomicroscopy are shown, with times indicated on the left. A representative full video is shown in Supplementary video S3.