Fig. 6.

Incubation at low pH results in a rapid and sustained phosphorylation of p38 MAP kinase, the downstream target MK2, and HSP27. Time kinetics for AGS cells were exposed to acid (pH 6.0) for the indicated time periods and phospho-p38, phosphr MK2 and phosphoHSP27 levels was measured by western blot. Total p38, MK2 and HSP27 was taken as loading control, and demonstrated that acid exposure did not change the amount of these proteins. The time kinetics experiment shows that even in the presence of stimuli the level of phosphorylated kinase comes down after 45 min. A short exposure of stimuli for 3 min did not have a long-lasting effect (3–3 min and 3–15 min). Level of increased phosphorylated kinase was down to the level of control after 15 min when stimulus was taken off after 3 min