Localization of pp60c-src in growth cone of PC12 cell.

By immunocytochemical and biochemical techniques, we observed the localization and expression of pp60c-src in nerve growth factor (NGF)-treated PC12 cells. Immunostaining of pp60c-src is detected in the neuronal soma and the tips of neurites (growth cones). Immunofluorescence in the neurites is less significant. High-resolution microscopy reveals that the location of pp60c-src in growth cone is in good agreement with the adhesive site of growth cone to the substratum. The pp60c-src kinase activity and the pp60c-src protein level increase 3.1- to 3.5-fold and 2.0-fold during differentiation of PC12 cells, respectively. The pp60c-src levels in the neurite fraction are also higher than those in the neuronal soma fraction. These results support the immunocytochemical finding that pp60c-src is localized in growth cones of differentiated PC12 cells. Furthermore, we discuss the possible role of pp60c-src in growth cone.