Fig. 5.

CNTF activates MAP kinase in the neuroepithelial stem cells. NP-40 extracts of cells treated with FGF (lanes 1–5) or CNTF (lanes 6–9) for the mentioned time points were resolved on 12.5% SDS-PAGE, proteins were blotted on nitrocellulose, and filters were probed with an anti-pan-ERK antibody. After incubation with the appropriate horseradish peroxidase, coupled secondary antibody protein bands were visualized with ECL. The major protein seen is the p44 MAP kinase, the phosphorylated form moving as the heavier band at time points in which activation is elicited. Activation of MAP kinase is slightly prolonged after FGF treatment when compared with CNTF treatment. Activation of MAP kinase is completely back to control levels (Mock, lane 6) at 4 hr after CNTF treatment (lane 9).