c-src gene product in developing rat brain is enriched in nerve growth cone membranes.
Differentiating rat neurons express high levels of the protooncogene product pp60c-src, a 60-kDa tyrosine kinase of unknown function encoded by c-src. pp60c-src was found to be concentrated at least 9-fold in membranes from a subcellular fraction of nerve growth cones, the motile tips of outgrowing neuronal processes. Indirect immunofluorescence staining of cultured chick retinal explants showed pp60c-src in neuronal growth cones and processes, with the antigen particularly concentrated in growth cones of long neurites. pp60c-src in growth cone membranes was an active tyrosine-specific protein kinase with elevated tyrosine-specific protein kinase activity and reduced electrophoretic mobility characteristic of the form of pp60c-src in central nervous system neurons. pp60c-src was present at lower levels in subcellular fractions from mature rat brain but synaptosomal membranes were not enriched. Preferential localization of an active form of pp60c-src in nerve growth cone membranes and persistence of pp60c-src in mature neurons suggest that this tyrosine kinase is important in growth cone-mediated neurite extension and synaptic plasticity.
Maness
P F
PF
Department of Biochemistry, University of North Carolina School of Medicine, Chapel Hill 27514.
Aubry
M
M
Shores
C G
CG
Frame
L
L
Pfenninger
K H
KH
D000818:Animals; D001369:Axons / Q000032:analysis*; D001921:Brain / Q000196:embryology* / Q000378:metabolism / Q000648:ultrastructure; D002458:Cell Fractionation; D002462:Cell Membrane / Q000032:analysis; D002499:Centrifugation, Density Gradient; D002642:Chick Embryo; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D007118:Immunoassay; D009474:Neurons / Q000032:analysis; D011494:Protein Kinases; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000032:analysis* / Q000378:metabolism; D016392:Proto-Oncogene Proteins pp60(c-src); D051381:Rats; D012160:Retina / Q000032:analysis / Q000196:embryology; D013574:Synaptosomes / Q000032:analysis
D011518:Proto-Oncogene Proteins; D011494:Protein Kinases; D011505:Protein-Tyrosine Kinases; D016392:Proto-Oncogene Proteins pp60(c-src)