ATP-induced MEK-ERK1/2 signalling contributes to NFAT activation. A, Effect of FK506 and PD98059 on ATP-induced NFAT activity. Cells were treated with ATP and the inhibitors as indicated. B and C, Activation of ERK1/2 by extracellular ATP. PC12 cells were stimulated with varying concentrations of ATP as indicated for 10 min before cells were lysed (B). Activation of ERK1 and ERK2 was detected by Western blot analysis with antibodies specific for the phosphorylated forms of ERK1 and ERK2 (P-ERK) and total ERK1/2 (panERK). In C and D, cells were pretreated for 30 min with either PPADS (10 μM), PD98059 (10 μM) or solvent (DMSO) or were not pretreated (Ø) before stimulation with ATP, or were kept under Ca2+-free conditions. P-ERK band intensities were quantified and normalised to the corresponding panERK signal. The graph in panel D presents the results of three independent experiments (means ± SD). Treatment with Ca2+-free medium was performed only twice, and here the mean of the two values is shown. Statistical significance of the results in A and D is indicated for differences vs. the control cells treated only with 300 μM ATP (*, p < 0.05; **, p < 0.01. ***, p < 0.001).
Prasai et al. BMC Neuroscience 2011 12:90 doi:10.1186/1471-2202-12-90