Coordinate alteration of pp60c-src abundance and c-src RNA expression in human neuroblastoma variants.
We examined the expression, abundance, and protein kinase activity of pp60c-src in two different pairs of genetically indistinguishable cloned human neuroblastoma cell variants which display altered phenotypes as the result of conversion from a neuronal to a non-neuronal phenotype. The results demonstrate that cells which exhibit the neuroblastic (N-type) phenotype possess high levels of pp60c-src protein and that one of the two N-type cell lines is capable of expressing the neuronal-specific isoenzyme of pp60c-src. In contrast, cells which display the substrate-adherent (S-type) phenotype have low levels of pp60c-src protein and express exclusively the non-neuronal isoenzyme of pp60c-src. In all cells examined the abundance of pp60c-src was found to be proportional to the steady-state level of c-src RNA. In each case the protein kinase activity of pp60c-src was found to be proportional to the abundance of the protein and independent of the ratio of neuronal to non-neuronal species of pp60c-src.
Veillette
A
A
Laboratory of Tumor Virus Biology, National Cancer Institute, Bethesda, Maryland 20892.
O'Shaughnessy
J
J
Horak
I D
ID
Israel
M A
MA
Yee
D
D
Rosen
N
N
Fujita
D J
DJ
Kung
H J
HJ
Biedler
J L
JL
Bolen
J B
JB
D006801:Humans; D009447:Neuroblastoma / Q000032:analysis / Q000235:genetics*; D010641:Phenotype; D011494:Protein Kinases / Q000032:analysis; D011518:Proto-Oncogene Proteins / Q000032:analysis*; D016392:Proto-Oncogene Proteins pp60(c-src); D011519:Proto-Oncogenes; D012334:RNA, Neoplasm / Q000032:analysis*; D014407:Tumor Cells, Cultured
D011518:Proto-Oncogene Proteins; D012334:RNA, Neoplasm; D011494:Protein Kinases; D016392:Proto-Oncogene Proteins pp60(c-src)