Serum-stimulated cell growth causes oscillations in casein kinase II activity.
We have tested the effects of serum-stimulated growth of quiescent WI38 human lung fibroblasts on cellular casein kinase II (CK-II) activity. Using the casein kinase II synthetic substrate RRREEETEEE we find a transient 6-fold elevation in CK-II activity in cell homogenates within 30 min following serum stimulation. Additional cycles of CK-II activation and inactivation are seen at 12 and 24 h after stimulation. The oscillations in CK-II activity are largely independent of de novo protein synthesis, and, thus, are likely to reflect cycles of post-translational activation and inhibition of the cellular kinase pool. In contrast to the activity profile of CK-II, we find that cyclic AMP-dependent protein kinase is rapidly inhibited upon serum-stimulation of WI38 cells. These results demonstrate that CK-II activity is subject to unique cellular regulation during proliferation and are consistent with the postulate that CK-II plays an important role in cell growth.
Carroll
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Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724.
Marshak
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DR
D000841:Anisomycin / Q000494:pharmacology; D047388:Casein Kinases; D002453:Cell Cycle; D002460:Cell Line; D003470:Culture Media; D004789:Enzyme Activation; D006133:Growth Substances / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D010507:Periodicity; D011494:Protein Kinases / Q000378:metabolism*
D003470:Culture Media; D006133:Growth Substances; D000841:Anisomycin; D011494:Protein Kinases; D047388:Casein Kinases