Depletion-activated calcium current is inhibited by protein kinase in RBL-2H3 cells.
Whole-cell patch-clamp recordings and single-cell Ca2+ measurements were used to study the control of Ca2+ entry through the Ca2+ release-activated Ca2+ influx pathway (ICRAC) in rat basophilic leukemia cells. When intracellular inositol 1,4,5-trisphosphate (InsP3)-sensitive stores were depleted by dialyzing cells with high concentrations of InsP3, ICRAC inactivated only slightly in the absence of ATP. Inclusion of ATP accelerated inactivation 2-fold. The inactivation was increased further by the ATP analogue adenosine 5'-[gamma-thio]triphosphate, which is readily used by protein kinases, but not by 5'-adenylyl imidodiphosphate, another ATP analogue that is not used by kinases. Neither cyclic nucleotides nor inhibition of calmodulin or tyrosine kinase prevented the inactivation. Staurosporine and bisindolylmaleimide, protein kinase C inhibitors, reduced inactivation of ICRAC, whereas phorbol ester accelerated inactivation of the current. These results demonstrate that a protein kinase-mediated phosphorylation, probably through protein kinase C, inactivates ICRAC. Activation of the adenosine receptor (A3 type) in RBL cells did not evoke much Ca2+ influx or systematic activation of ICRAC. After protein kinase C was blocked, however, large ICRAC was observed in all cells and this was accompanied by large Ca2+ influx. The ability of a receptor to evoke Ca2+ entry is determined, at least in part, by protein kinase C. Antigen stimulation, which triggers secretion through a process that requires Ca2+ influx, activated ICRAC. The regulation of ICRAC by protein kinase will therefore have important consequences on cell functioning.
Parekh
A B
AB
Department of Membrane Biophysics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
Penner
R
R
D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology*; D019830:Adenosine-5'-(N-ethylcarboxamide); D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology*; D002460:Cell Line; D003956:Dialysis; D004533:Egtazic Acid / Q000494:pharmacology; D016257:Fura-2 / Q000031:analogs & derivatives; D006706:Homeostasis; D007211:Indoles / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology*; D007700:Kinetics; D015471:Leukemia, Basophilic, Acute; D008301:Maleimides / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats; D018047:Receptors, Purinergic P1 / Q000187:drug effects / Q000502:physiology; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D000470:Alkaloids; D015220:Calcium Channels; D007211:Indoles; D008301:Maleimides; D018047:Receptors, Purinergic P1; C049925:fura-2-am; C022571:adenosine 5'-O-(3-thiotriphosphate); D019830:Adenosine-5'-(N-ethylcarboxamide); D004533:Egtazic Acid; D015544:Inositol 1,4,5-Trisphosphate; D000255:Adenosine Triphosphate; D011494:Protein Kinases; D011493:Protein Kinase C; D019311:Staurosporine; D000241:Adenosine; C088060:bisindolylmaleimide; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium; D016257:Fura-2