Avian and Human Homologues of the P2Y₁ Receptor: Pharmacological, Signaling, and Molecular Properties

[Table: see text] The P2Y receptor on turkey erythrocyte membranes was the first P2 receptor to be shown to activate phospholipase C (PLC) in a strictly guanine nucleotide-dependent manner and remains the only G protein-coupled P2 receptor for which G protein-coupling kinetics have been defined. This membrane receptor has provided a model system for detailed pharmacological analyses of a series of chain-extended 2-thioether derivatives of adenine nucleotides that exhibit remarkable selectivity and potency for P2Y receptors. This model system also has led recently to identification of a novel series of P2 receptor antagonists. The turkey erythrocyte receptor is the species homologue of the chick P2Y₁ receptor originally cloned by Webb and coworkers [Webb et al., 1993]. We also have cloned the human homologue of the P2Y₁ receptor, which exhibits identical pharmacological and second messenger signaling properties to that of the avian P2Y₁ receptor.