Fig. 8.
Phosphorylation motifs. Sixteen phosphorylation motifs modified by different kinases that are represented at the top of the figure were analyzed for the regulated phosphopeptides by determining their enrichment in each population. The upper panel represents the enrichment factor (see text for definition) of each motif in the up (dark gray bars) and down- (light gray bars) regulated phosphopeptides upon stimulation of PTR. The lower panel shows the same analysis on up-regulated phosphopeptides upon stimulation of PTR (dark gray bars) and EGFR in Hela cells (9) (white bars).