Fig. 7. (A) Scrape wounding increases phosphorylation of p38 and ATF2. HKs were grown to confluence and multiple scrape wounds were generated in the monolayer. Triton-soluble extracts were collected in non-wound HKs (Quiescent), or in wounded HKs at the time of wounding, (0 hour), and 30 minutes, 1 hour, 2 hours and 3 hours post wounding. Levels of p38 remained constant but P-p38 increased by 0.5 hours after wounding and P-ATF2 increased immediately after wounding. (B) p38 kinase activity is elevated in suspended or wounded HKs. Confluent quiescent HKs (Quiescent) were assayed for p38 kinase after suspension for 3 hours (Suspended) or scrape wounding for 6 hours (Wounded). In vitro assay of p38 kinase activity was performed as described (see Materials and Methods) using ATF2 as substrate and immunoblotting for P-ATF2. Aliquots of the cell extracts were also immunoblotted (Immunoblot) for P-p38 to confirm that levels of P-p38 correlated with p38 kinase activity.