Depletion-Activated Calcium Current is Inhibited by Protein Kinase in RBL-2H3 Cells

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 92; no. 17; pp. 7907 - 7911
• Main Authors: Parekh, Anant B., Penner, Reinhold
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 15-08-1995; National Acad Sciences; National Academy of Sciences
• Subjects: Adenosine - analogs & derivatives; Adenosine - pharmacology; Adenosine Triphosphate - analogs & derivatives; Adenosine Triphosphate - pharmacology; Adenosine-5'-(N-ethylcarboxamide); Agonists; Alkaloids - pharmacology; Anatomy & physiology; Animals; Antigens; Calcium; Calcium - metabolism; Calcium Channels - physiology; Cell Line; Cells; Dialysis; Egtazic Acid - pharmacology; Fura-2 - analogs & derivatives; Homeostasis; Indoles - pharmacology; Inositol 1,4,5-Trisphosphate - pharmacology; Kinetics; Leukemia; Leukemia, Basophilic, Acute; Maleimides - pharmacology; Mast cells; Patch-Clamp Techniques; Phosphorylation; Physiological regulation; Pipettes; Protein Kinase C - antagonists & inhibitors; Protein Kinases - metabolism; Proteins; Rats; Receptors; Receptors, Purinergic P1 - drug effects; Receptors, Purinergic P1 - physiology; Rodents; Secretion; Staurosporine; Tetradecanoylphorbol Acetate - pharmacology; Tumor Cells, Cultured
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.92.17.7907

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, ICRACinactivated 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'-[γ-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 (A3type) in RBL cells did not evoke much Ca2+influx or systematic activation of ICRAC. After protein kinase C was blocked, however, large ICRACwas 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 ICRACby protein kinase will therefore have important consequences on cell functioning.