Protein kinase C activation selectively increases mRNA levels for one of the regulatory subunits (RI alpha) of cAMP-dependent protein kinases in HT-29 cells.
We have examined the effect of the protein kinase C activator, TPA, on mRNA levels for subunits of cAMP-dependent protein kinases in the human colonic cancer cell line HT-29, subline m2. Messenger RNA for the regulatory subunit, RI alpha, of cAMP-dependent protein kinases was shown to be present and regulated by TPA. Other mRNAs for subunits of cAMP-dependent protein kinases (RI beta, RII alpha, RII beta, C alpha, C beta) were also present in these cells, but revealed no or only minor changes upon TPA stimulation. When HT-29 cells were cultured in the presence of 10 nM TPA for various time periods, a biphasic response was observed in RI alpha mRNA levels with a maximal increase (approximately 4 fold) after 24 hours. TPA stimulated RI alpha mRNA increased in a concentration-dependent manner and maximal response (4-8 fold) was seen at 3-10 nM. The TPA-induced increase in RI alpha mRNA was not obtained when cells were incubated with TPA together with the protein kinase C inhibitors, staurosporine or H7. The cAMP-analog 8-CPTcAMP alone induced RI alpha mRNA levels 50% more than TPA. Combined treatment with TPA (10 nM) and 8-CPTcAMP (0.1 mM) gave an increase in RI alpha mRNA similar to TPA. These results demonstrate an interaction between the protein kinase C pathway and mRNA levels for the RI alpha subunit of cAMP-dependent protein kinases in HT-29 cells.
Taskén
K
K
Institute of Pathology, Rikshospitalet, Oslo, Norway.
Kvale
D
D
Hansson
V
V
Jahnsen
T
T
D015152:Blotting, Northern; D002460:Cell Line; D003110:Colonic Neoplasms; D015342:DNA Probes; D004789:Enzyme Activation; D006801:Humans; D046911:Macromolecular Substances; D011493:Protein Kinase C / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics*; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D015342:DNA Probes; D046911:Macromolecular Substances; D012333:RNA, Messenger; D011494:Protein Kinases; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate