Activation of cyclic adenosine 3':5'-monophosphate-dependent protein kinase in H35 hepatoma and Chinese hamster ovary cells by a phorbol ester tumor promoter.
The ability of the phorbol ester tumor promoter 12-O-tetradecanoylphorbol- 13-acetate (TPA) to lead to the activation of cyclic adenosine 3':5'-monophosphate (cAMP)-dependent protein kinase was investigated in three cell lines. In the Reuber H35 hepatoma cells, TPA (1.6 microM) led to an increase in the protein kinase activity ratio from a value of 0.13 in control cultures to 0.40 in the stimulated cells within 30 min of addition. A specific fluorescent cytochemical procedure was further utilized to study the intracellular localization of the free catalytic subunit following activation of the holoenzyme by TPA. A marked increase in cytoplasmic and nucleolar fluorescence indicative of the appearance of the free catalytic subunit (activation of cAMP-dependent protein kinase) in these cellular compartments was observed in both Reuber H35 hepatoma and Chinese hamster ovary 10001 cells incubated with TPA (1.6 microM) for 30 min. In the H35 cells monitored with the cytochemical probe for the catalytic subunit, protein kinase was activated within 5 min of the addition of TPA (1.6 microM) with 0.16 microM TPA in the culture medium resulting in the maximal degree of activation. No increase in intracellular fluorescence throughout a 40-min period was observed in a cAMP-dependent protein kinase-deficient mutant strain Chinese hamster ovary 10260 cells incubated with TPA. These studies indicate that, while TPA does lead to the marked activation of cAMP-dependent protein kinase in at least two cell types shown to be responsive to TPA, this activation may be only one of several rapid events which mediate the many specific effects of the phorbol esters.
D000818:Animals; D001711:Biotransformation; D002352:Carrier Proteins / Q000032:analysis; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D000242:Cyclic AMP / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D047908:Intracellular Signaling Peptides and Proteins; D008114:Liver Neoplasms, Experimental / Q000378:metabolism*; D009154:Mutation; D010053:Ovary; D010703:Phorbol Esters / Q000494:pharmacology*; D010704:Phorbols / Q000494:pharmacology*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D010703:Phorbol Esters; D010704:Phorbols; C015482:protein kinase modulator; D000242:Cyclic AMP; D011494:Protein Kinases