Abstract
Retroviral vectors containing five different protein kinase C (PKC) isoenzymes (alpha, delta, epsilon, eta, zeta) were expressed in 32D hematopoietic cells and NIH-3T3 fibroblasts. In an effort to investigate signaling events regulated by PKC activation, we analyzed whether tyrosine phosphorylation of cellular proteins would occur after 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment of the various transfectants. While no detectable tyrosine-specific phosphorylation was observed after treatment of the majority of the transfectants, pronounced TPA-dependent tyrosine phosphorylation of an 82-kDa protein was detected in the 32D/PKC-delta and NIH-3T3/PKC-delta lines. Interestingly, the 82-kDa substrate proved to be PKC-delta itself. Tyrosine phosphorylation of purified PKC-delta by src family or receptor tyrosine kinases in vitro enhanced PKC-delta activity, suggesting that tyrosine phosphorylation of PKC-delta may positively affect its function.
MeSH terms
-
3T3 Cells
-
Adenosine Triphosphate / metabolism
-
Amino Acid Sequence
-
Animals
-
Electrophoresis, Polyacrylamide Gel
-
Enzyme Activation
-
Genes, src
-
Interleukin-3 / pharmacology
-
Isoenzymes / biosynthesis
-
Isoenzymes / isolation & purification
-
Isoenzymes / metabolism*
-
Mice
-
Molecular Sequence Data
-
Molecular Weight
-
Phosphopeptides / chemistry
-
Phosphopeptides / isolation & purification
-
Phosphoproteins / isolation & purification
-
Phosphoproteins / metabolism*
-
Phosphorylation
-
Phosphotyrosine
-
Protein Kinase C / biosynthesis
-
Protein Kinase C / isolation & purification
-
Protein Kinase C / metabolism*
-
Receptor Protein-Tyrosine Kinases / metabolism
-
Recombinant Proteins / biosynthesis
-
Recombinant Proteins / isolation & purification
-
Recombinant Proteins / metabolism
-
Substrate Specificity
-
Tetradecanoylphorbol Acetate / pharmacology
-
Transfection
-
Tyrosine / analogs & derivatives*
-
Tyrosine / analysis
Substances
-
Interleukin-3
-
Isoenzymes
-
Phosphopeptides
-
Phosphoproteins
-
Recombinant Proteins
-
Phosphotyrosine
-
Tyrosine
-
Adenosine Triphosphate
-
Receptor Protein-Tyrosine Kinases
-
Protein Kinase C
-
Tetradecanoylphorbol Acetate