Effects of a peptide analogue of the amphiphilic domain of the common neurotrophin receptor on nerve growth factor-mediated motility of human neuroblastoma cells.

Exposure of human neuroblastoma cells (IMR-32) to a peptide mimic of the cytoplasmic amphiphilic domain of the common neurotrophin receptor (p75NTR 367-379) resulted in enhanced nerve growth factor (NGF)-mediated inhibition of cell invasion in vitro. The peptide also enhanced NGF-mediated neurite extension and GAP-43 gene expression but had no effect on NGF-mediated cell survival. These latter functional effects mimicked influences on NGF-mediated neurite growth in other trkA-positive cells as reported previously. NGF-dependent trkA phosphorylation was significantly enhanced by the presence of the peptide, whereas high-affinity binding of 125I-NGF, both NGF receptors mRNA and protein expression, and trkA dimer/monomer ratios were not influenced. The studies suggest that ligand-mediated trkA activation has differential effects on cell motility phenomena and that the amphiphilic domain of p75NTR has a role in this differential signaling.