RT Journal Article
SR Electronic
T1 A Molecularly Identified P2Y Receptor Simultaneously Activates Phospholipase C and Inhibits Adenylyl Cyclase and Is Nonselectively Activated by All Nucleoside Triphosphates
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 805
OP 810
DO 10.1124/mol.57.4.805
VO 57
IS 4
A1 José L. Boyer
A1 Suzanne M. Delaney
A1 Demetrio Villanueva
A1 T. Kendall Harden
YR 2000
UL http://molpharm.aspetjournals.org/content/57/4/805.abstract
AB We recently cloned and expressed a novel P2Y receptor (tp2y receptor) from a turkey cDNA library. Expression of this receptor in 1321N1 human astrocytoma cells confers nucleotide-dependent stimulation of phospholipase C activity; however, as we demonstrate here, it also confers nucleotide-dependent inhibition of adenylyl cyclase. Both the phospholipase C and adenylyl cyclase responses were promoted by receptor agonists over a similar range of concentrations. Moreover, not only did UTP and ATP activate the avian receptor but ITP, GTP, xanthosine 5′-triphosphate, and CTP were also agonists, with EC50 values ranging between 0.1 and 1 μM. Similar potencies, rank-order, and selectivity of nucleotide agonists were also demonstrated for intracellular Ca2+ mobilization measured during a 30-s stimulation under constant superfusion conditions. This observation indicates that receptor activation by nucleoside 5′-triphosphates is not produced by interconversion of these nucleotides into ATP or UTP. Pretreatment of cells with pertussis toxin completely abolished the inhibitory effect of nucleotide agonists on adenylyl cyclase, whereas the activation of phospholipase C was only partially inhibited. These results demonstrate that the avian P2Y receptor is a nucleoside triphosphate receptor of broad agonist selectivity that interacts with both pertussis toxin-insensitive and -sensitive G proteins to activate phospholipase C and to inhibit adenylyl cyclase. This is the first cloned P2Y receptor that is clearly Gi/adenylyl cyclase-linked.