Differential regulation of P2Y(11) receptor-mediated signalling to phospholipase C and adenylyl cyclase by protein kinase C in HL-60 promyelocytes

• Published in: British journal of pharmacology Vol. 131; no. 3; p. 489
• Main Authors: Suh, B C, Kim, T D, Lee, I S, Kim, K T
• Format: Journal Article
• Language: English
• Published: England 01.10.2000
• Subjects: Adenylyl Cyclases - metabolism; Biological Transport; Calcium - metabolism; Cyclic AMP - metabolism; Enzyme Activation; HL-60 Cells; Humans; Inositol 1,4,5-Trisphosphate - metabolism; Nucleotides - metabolism; Protein Kinase C - metabolism; Receptors, Purinergic P2 - metabolism; Signal Transduction; Tetradecanoylphorbol Acetate - pharmacology; Type C Phospholipases - metabolism
• ISSN: 0007-1188
• DOI: 10.1038/sj.bjp.0703581

The regulatory mode of the P2Y(11) purinoceptor-mediated signalling cascades towards phospholipase C and adenylyl cyclase was studied in HL-60 promyelocytes. Treatment with the potent P2Y(11) receptor activator dATP evoked an elevated intracellular Ca(2+) concentration ([Ca(2+)](i)) and inositol 1,4,5-trisphosphate (IP(3)) production that was sustained for longer than 30 min. However, the dATP-induced responses were significantly inhibited by the activation of protein kinase C after a short exposure to phorbol 12-myristate 13-acetate (PMA). dATP also potently stimulated cyclic AMP production with half maximum effect seen at 23+/-7 microM dATP. In addition, a 5-min pretreatment with PMA enhanced the dATP-stimulated cyclic AMP accumulation. PMA potentiated the cyclic AMP production when adenylyl cyclase was activated directly by forskolin or indirectly by G protein activation after cholera toxin treatment. dATP also enhanced the forskolin-mediated cyclic AMP generation. Treatment of the cells with 10 microM U-73122, which almost completely blocked the dATP-stimulated IP(3) production and [Ca(2+)](i) rise, had no effect on cyclic AMP accumulation, while 10 microM 9-(tetrahydro-2-furyl)adenine (SQ 22536), which inhibited the adenylyl cyclase activation, did not effect the dATP-stimulated phosphoinositide turnover. Taken together, the results indicate that P2Y(11) receptor-mediated activation of phospholipase C and adenylyl cyclase occurs through independent pathways and is differentially regulated by protein kinase C in HL-60 cells.