Fig. 4.

MLK3 activity is increased after NGF withdrawal in PC12 cells and in SCG neurons. MLK3 kinase assays were performed in differentiated PC12 cells (A, B) and in SCG neurons (5 DIV; C) that had been maintained in the presence of NGF or withdrawn from NGF for 3, 5, and 7 hr, as described in Materials and Methods. Fold activation of MLK3 activity was obtained by scanning the gels on a STORM PhosphorImager. A representative autoradiograph of a MLK3 kinase assay in PC12 cells is shown inA. The level of MLK3 activity at time 0was set at 1. The results are the mean of three independent experiments ± SEM.