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Attenuation of signal flow from P2Y 6 receptor by protein kinase C‐α in SK‐N‐BE(2)C human neuroblastoma cells
Author(s) -
Lee Hyun,
Choi BoHwa,
Suh ByungChang,
Lee SunKyong,
Kim KyongTai
Publication year - 2003
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2003.01761.x
Subject(s) - p2y receptor , receptor , pertussis toxin , inositol phosphate , microbiology and biotechnology , biology , protein kinase c , extracellular , stimulation , g protein , kinase , inositol , endocrinology , purinergic receptor , biochemistry
Extracellular nucleotides exert a variety of biological actions through several kinds of P2 receptors in many tissues and cell types. We found that treatment with nucleotides increases intracellular Ca 2+ concentration ([Ca 2+ ] i ) in SK‐N‐BE(2)C human neuroblastoma cells with a following order of potency: UDP > UTP > ADP >> ATP. Reverse transcription‐polymerase chain reaction (RT‐PCR) analysis showed that specific mRNAs coding for human P2Y 1 , P2Y 4 , and P2Y 6 receptors were expressed in the cells, but Northern blot analysis revealed that P2Y 6 receptors were the predominant type. Activation of protein kinase C‐α by treatment with 1 µ m phorbol 12‐myristate 13‐acetate dramatically inhibited both the UDP‐induced [Ca 2+ ] i rise and inositol 1,4,5‐trisphosphate (IP 3 ) generation, whereas incubation with pertussis toxin had little effect on the responses. The UDP‐induced [Ca 2+ ] i rise and IP 3 production were maintained up to 30 min after stimulation, while bradykinin‐induced responses rapidly decreased to the basal level within 5 min of stimulation. Pretreatment of cells with the maximal effective concentration of UDP reduced the subsequent carbachol‐ or bradykinin‐induced [Ca 2+ ] i rise without inhibition of IP 3 generation. Neuronal differentiation of the cells by treatment with retinoic acid for 7 days did not change the expression level of P2Y 6 receptors. Taken together, the data indicate that P2Y 6 receptors highly responsive to diphosphonucleotide UDP are endogenously expressed in the human neuroblastoma SK‐N‐BE(2)C cells and that they are involved in the modulation of other phospholipase C‐coupled receptor‐mediated Ca 2+ mobilization by depleting the IP 3 ‐sensitive Ca 2+ stores.