NGF and other growth factors induce an association between ERK1 and the NGF receptor, gp140^prototrk

As detected by coimmunoprecipitation from PC12 cells, NGF induces rapid association between ERK1 (a growth factor-activated serine/threonine protein kinase) and gp140^prototrk NGF receptors. In contrast, no such association is found with the closely related ERK2. Anti-trk immunocomplexes generated from NGF-treated cells also contain protein kinase activity that shares many properties with soluble ERK1. The association of both ERK1 protein and ERK-like kinase activity with gp140^prototrk is maximal by 5 min of NGF treatment, persists for approximately 1 hr, and subsequently declines by 18 hr. Treatment with either basic fibroblast growth factor, epidermal growth factor, or orthovanadate also leads to association of ERK1 with gp140^prototrk without tyrosine phosphorylation of the latter. The interaction between ERK1 and gp140^prototrk may prove relevant to the NGF mechanism.