Dual regulation of the n type K+ channel in Jurkat T lymphocytes by protein kinases A and C.
We have measured the activity of the n type K+ channel present in human (Jurkat) T lymphocytes using the patch clamp technique in the whole-cell configuration. We report that protein kinase A (PKA) and protein kinase C (PKC) modulate, in a dual manner, the K+ conductance in these cells. Activation of PKA decreases the amplitude of the current, as previously reported (Bastin, B., Payet, M. D., and Dupuis, G. (1990) Cell. Immunol. 128, 385-399), and this is also the case for 12-O-tetradecanoylphorbol-13-acetate-dependent activation of PKC. In contrast, inhibitors of PKC (H7, staurosporine, polymixin B, and anti-PKC antibody) increase the current amplitude. Of importance, down-regulation of PKC or its inhibition prevented the PKA-dependent inhibition of the K+ channels. Addition of alkaline phosphatase via the patch pipette increased the K+ conductance under basal conditions and reversed the inhibition produced by PKA. The dual modulation of K+ channels in Jurkat T cells is in agreement with the presence of consensus sequences in the primary structure of the n type K+ channel.
Payet
M D
MD
Department of Physiology and Biophysics, Faculty of Medicine, University of Sherbrooke, Quebec, Canada.
Dupuis
G
G
D000469:Alkaline Phosphatase / Q000378:metabolism; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D015536:Down-Regulation; D004789:Enzyme Activation; D008564:Membrane Potentials; D010766:Phosphorylation; D015221:Potassium Channels / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D013601:T-Lymphocytes / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D015221:Potassium Channels; D000242:Cyclic AMP; D011494:Protein Kinases; D011493:Protein Kinase C; D000469:Alkaline Phosphatase; D013755:Tetradecanoylphorbol Acetate