Fig. 5.

Activation of TrkA shifts the balance between MAP kinases and JNK. Control differentiated cultures infected with the control virus (p75⁺) and cultures infected with the TrkA virus (p75 +TrkA) were treated or left untreated with 100 ng/ml NGF for 5 min or 4 hr. Lysates were prepared and subjected to immunoprecipitation/kinase assays, using MBP as a substrate for MAP kinase activity and GST-jun as a substrate for JNK activity. The experiments were repeated three times with similar results.