Fig. 5.

Temporally distinct ERK1/2 activation by apical and basolateral PAR₂. A and B: polarized Caco2-BBe monolayers were treated with 2fAP at either the apical (A) or the basolateral (B) surface for 0–60 min. Representative Western blot analyses performed with anti-phospho-ERK1/2 (pERK, top) and anti-total ERK2 (tERK, bottom) and imaged using the LICOR-Odyssey 2 color Infrared Imaging system are shown. Integrated intensities of each band were determined, pERK levels were normalized to tERK, and fold changes in normalized pERK in treated versus untreated samples were determined. C: bar graph depicting mean ± SE fold increase over baseline in normalized pERK. Baseline is defined as normalized pERK from untreated cells. Statistically significant increases in ERK1/2 activation were determined by ANOVA and differences between experimental groups were determined by two-tailed t-tests: *P < 0.04, **P < 0.005, n = 4.