Interferon-gamma and interleukin-1 alpha induce transient translocation of protein kinase C activity to membranes in a B lymphoid cell line. Evidence for a protein kinase C-independent pathway in lymphokine-induced cytoplasmic alkalinization.
We have previously shown that recombinant murine interferon-gamma, rIFN-gamma, and recombinant human interleukin-1 alpha, rIL-1 alpha, induce differentiation of murine pre-B-like cell line 70Z/3, a finding associated with stimulation of Na+/H+ exchange across the plasma membrane. The present study was designed to test whether the enhanced Na+/H+ exchange is mediated by Ca2+/phospholipid-dependent protein kinase C. The results show that two structurally different peptides, rIFN-gamma and rIL-1 alpha, induce identical patterns of transient translocation of protein kinase C from the cytosol to the membranes. The increase in membrane-associated protein kinase C activity was first detected 20 min after exposure to the lymphokines. This activity peaked at 30 min and was back to baseline by 2 h. At each time point, the increase in membrane-associated protein kinase C activity corresponded to a decrease in the activity of protein kinase C in the cytoplasmic fraction. The total cellular activity (cytosol + membrane) remained the same. Two series of experiments were carried out to test the role of protein kinase C in mediating the lymphokine-stimulated Na+/H+ exchange. In the first, the effects of rIFN-gamma and rIL-1 alpha on cytoplasmic pH were measured in the presence of a protein kinase C inhibitor 1-(5-isoquinolinesulfonyl)-2-methylpiperazine, H-7. In the second, rIFN-gamma- and rIL-1 alpha-induced cytoplasmic alkalinization was determined in cells containing decreased protein kinase C activity. Under both experimental conditions, lymphokine-induced cytoplasmic alkalinization was not attenuated. These results indicate that, although both rIFN-gamma and rIL-1 alpha cause association of protein kinase C with membranes, activation of protein kinase C is not required for rIFN-gamma or rIL-1 alpha to stimulate Na+/H+ exchange across the plasma membrane.
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000818:Animals; D001402:B-Lymphocytes / Q000201:enzymology*; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D003593:Cytoplasm / Q000378:metabolism*; D003600:Cytosol / Q000201:enzymology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007371:Interferon-gamma / Q000494:pharmacology*; D007375:Interleukin-1 / Q000494:pharmacology*; D007546:Isoquinolines / Q000494:pharmacology; D051379:Mice; D010879:Piperazines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007375:Interleukin-1; D007546:Isoquinolines; D010879:Piperazines; D007371:Interferon-gamma; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate