Regulation of casein kinase II by growth factors: a reevaluation.
Many of the effects of growth factors or hormones are mediated through the activation of protein kinase cascades. In this regard, it is well established that the activity of several protein kinases can be dramatically increased when cells are treated with a variety of stimuli. Since 1987, there have been several reports demonstrating that the activity of casein kinase II (CKII) can be acutely increased by hormones or growth factors. However, these are a number of discrepancies regarding the activation of CKII. In this study, we have examined CKII activities in extracts prepared from cells following treatment with stimuli that had been previously shown to elicit dramatic increases in CKII activity. Human WI.38 diploid lung fibroblasts were stimulated with serum or a variety of other stimuli including insulin, platelet-derived growth factor, fibroblast growth factor, epidermal growth factor, or phorbol myristate acetate. Human A431 epidermal carcinoma cells were similarly treated with epidermal growth factor. No reproducible increases in CKII activity were observed in response to any of these treatments. By comparison, a dramatic increase in kinase activity towards a synthetic peptide based on phosphorylation sites within the ribosomal S6 protein was consistently measured. Our observations indicate that CKII is not regulated in a similar manner by growth factors as are the protein kinases of the MAP kinase cascade, e.g., MAP kinase itself or ribosomal protein S6 kinase.
Litchfield
D W
DW
Manitoba Institute of Cell Biology, Manitoba Cancer Treatment and Research Foundation, Winnipeg, Canada.
Dobrowolska
G
G
Krebs
E G
EG
D000595:Amino Acid Sequence; D000818:Animals; D001839:Bombesin / Q000494:pharmacology; D002294:Carcinoma, Squamous Cell / Q000473:pathology; D047390:Casein Kinase II; D002417:Cattle; D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D004789:Enzyme Activation / Q000187:drug effects; D004790:Enzyme Induction / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005312:Fetal Blood; D005346:Fibroblast Growth Factors / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology; D006133:Growth Substances / Q000494:pharmacology*; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D015759:Ionomycin / Q000494:pharmacology; D008168:Lung; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000378:metabolism; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000494:pharmacology*; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism* / Q000502:physiology; D038601:Ribosomal Protein S6; D019893:Ribosomal Protein S6 Kinases; D012269:Ribosomal Proteins / Q000737:chemistry / Q000378:metabolism; D015398:Signal Transduction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D006133:Growth Substances; D007328:Insulin; D009363:Neoplasm Proteins; D010446:Peptide Fragments; D010982:Platelet-Derived Growth Factor; D038601:Ribosomal Protein S6; D012269:Ribosomal Proteins; D015759:Ionomycin; D005346:Fibroblast Growth Factors; D004815:Epidermal Growth Factor; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases; D019893:Ribosomal Protein S6 Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D013755:Tetradecanoylphorbol Acetate; D001839:Bombesin