Figure 5.

NGF treatment of PC12/TrkA and squid giant synapse promotes phosphorylation of TrkA receptors that can be blocked by the protein kinase inhibitor K252a. Lysates of NGF-stimulated (+) or NGF-unstimulated (−) PC12 cells (A) or squid giant synapse (B) were immunoprecipitated with anti-Trk antibodies (IP: anti-Trk) and were immunoblotted with antiphosphotyrosine antibodies (anti-pTyr). PC12 cells (C) and synapses (D) were preincubated for 15 min with 200 nM K252a (+) or not preincubated with K252a (−) then stimulated with NGF (+) and submitted to the same protocol as in A and B. The migration of the TrkA-phosphorylated product is indicated by the arrows. In both cases, NGF concentration was 200 ng/ml and was performed for 15 min.