Fig. 2.

EP4, PKA, and Rap are involved in PGE₂ activation of ERK1/2. NVMs were treated with PGE₂ for 5 min after pretreatment with either ONO or H89 for 1 h. Cells were lysed for the Western blot analysis of total and phosphorylated (p-)ERK1/2. A: EP4 dependence of p-ERK1/2 activation. p-ERK1/2 is expressed as a percentage of PGE₂ stimulation in n = 7 experiments. #P ≤ 0.01 vs. PGE₂. B: Involvement of Rap in the PGE₂ activation of ERK1/2. NVMs were transfected with either dominant negative (dn)Rap, dnRas, or a control plasmid (vector) for 24 h. Cells were then treated with PGE₂ for 5 min and lysed for protein extraction and Western blot analysis. p-ERK/2 is expressed as the fold increase versus the control vector in NVM without PGE₂ treatment. Data are means ± SE from 5 separate experiments. #P ≤ 0.01 vs. vector + PGE₂. C: involvement of PKA. p-ERK1/2 activation is expressed as the fold increase versus the control in n = 4 experiments. #P ≤ 0.01 vs. PGE₂.