Tyrosine phosphorylation of protein kinase C-delta in response to its activation.
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.
Li
W
W
Laboratory of Cellular and Molecular Biology, National Cancer Institute, Bethesda, Maryland 20892.
Mischak
H
H
Yu
J C
JC
Wang
L M
LM
Mushinski
J F
JF
Heidaran
M A
MA
Pierce
J H
JH
D016475:3T3 Cells; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D016391:Genes, src; D007377:Interleukin-3 / Q000494:pharmacology; D007527:Isoenzymes / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010748:Phosphopeptides / Q000737:chemistry / Q000302:isolation & purification; D010750:Phosphoproteins / Q000302:isolation & purification / Q000378:metabolism*; D010766:Phosphorylation; D019000:Phosphotyrosine; D011493:Protein Kinase C / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D013379:Substrate Specificity; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000032:analysis
D007377:Interleukin-3; D007527:Isoenzymes; D010748:Phosphopeptides; D010750:Phosphoproteins; D011994:Recombinant Proteins; D019000:Phosphotyrosine; D014443:Tyrosine; D000255:Adenosine Triphosphate; D020794:Receptor Protein-Tyrosine Kinases; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate