Fig. 2.

PrP^C stimulation induces MEK-ERK1/2 phosphorylation. 1C11 precursor, 1C11^5-HT serotonergic and 1C11^NE noradrenergic cells, GT1-7 hypothalamic cells, and BW5147 and Thy1^-e lymphoid cell lines were stimulated for 5 min by using various PrP-targeted antibodies (10 μg·ml^-1) or PMA (1 μM), a potent activator of PKCs. (a) Stimulated 1C11 progenitor cells lysates were immunoblotted by using ERK1/2 [pTpY185/187] antibody. Control experiments (Ctrl) with unstimulated cells were also performed. (b) ERK1/2 phosphorylation profiles of 1C11^5-HT, 1C11^NE, and GT1-7 cells and of BW5147 and Thy1^-e lymphoid cell lines are compared. All cells were submitted to stimulation by the SAF61 antibody. Also shown are the control experiments without antibody addition. (c) Selective inhibition of MEK1/2 abrogates PrP^C-induced ERK activation. Before PrP^C–antibody stimulation, cells were preincubated for 45 min in the presence of PD98059, a selective inhibitor of MEK (5 μM with 1C11 precursor, 1C11^5-HT and 1C11^NE cells and with BW5147 T lymphocytes and 20 μM with GT1-7 cells). Cytosolic extracts were immunoblotted by using the ERK1/2 [pTpY185/187] antibody. In all sets of experiments, it was checked that the PD98059 concentration used did not impair cell viability according to trypan blue staining. Data shown are representative of a set of three independent experiments.