Activation of distinct protein kinase C isozymes by phorbol esters: correlation with induction of interleukin 1 beta gene expression.
Treatment of human promyelocytic leukemia cells U937 with phorbol 12-myristate 13-acetate (TPA) induces them to differentiate into monocytic cells [Harris, P., & Ralph, P. (1985) J. Leukocyte Biol. 37, 407-422]. Here we investigated the effects of TPA on interleukin 1 gene expression and the possible role of protein kinase C (PKC) in this process. Addition of TPA to serum-starved U937 cells induced the expression of the interleukin 1 beta (IL-1 beta) gene. This effect was apparent as early as 2 h and peaked at 24 h in the presence of 5 X 10(-8) M TPA. Higher concentrations of TPA, which partially or totally depleted protein kinase C levels in the cells (10(-9)-2 X 10(-5) M), had an inhibitory effect on IL-1 beta mRNA expression. Cell-permeable 1,2-dioctanoyl-sn-glycerol (diC8), a diacylglycerol that activates PKC in intact cells and cell-free systems, did not mimic the effect of TPA on the IL-1 beta mRNA induction. To determine the protein kinase C isozymes present in the control and TPA- (5 X 10(-8) M) treated U937 cells, we prepared antipeptide antibodies that specifically recognize the alpha, beta, and gamma isoforms of protein kinase C in rat brain cytosol and U937 cell extracts. In "control" U937 cells, 30% of PKC alpha was particulate, and PKC beta was cytosolic, while there was no detectable PKC gamma.(ABSTRACT TRUNCATED AT 250 WORDS)
Strulovici
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B
Cancer and Developmental Biology, Syntex Research, Palo Alto, California 94304.
Daniel-Issakani
S
S
Oto
E
E
Nestor
J
J
Chan
H
H
Tsou
A P
AP
D000918:Antibody Specificity; D004789:Enzyme Activation / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics*; D007527:Isoenzymes / Q000276:immunology / Q000378:metabolism*; D010455:Peptides / Q000276:immunology; D010703:Phorbol Esters / Q000494:pharmacology*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000276:immunology / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
D007375:Interleukin-1; D007527:Isoenzymes; D010455:Peptides; D010703:Phorbol Esters; D012333:RNA, Messenger; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate