P-2-PURINERGIC RECEPTORS - SUBTYPE-ASSOCIATED SIGNALING RESPONSES ANDSTRUCTURE

Extracellular adenine nucleotides interact with Pz-purinergic receptor s to regulate a broad range of physiological processes. These receptor s include the P-2Y-, P-2U-, P-2T, P-2X-, and P-2Z-purinergic receptor subtypes. This review focuses on the first three of these receptor sub types, which couple to G proteins and regulate the inositol lipid, cyc lic AMP, and other second-messenger signaling cascades. Both pharmacol ogical data and the occurrence of selectivity of coupling to second-me ssenger pathways indicate the existence of multiple members in several of the classes of P-2-purinergic receptor subtypes. Complementary DNA s cloned for P-2Y- and P-2U-purinergic receptors predict proteins with seven transmembrane-spanning motifs, typical of that of other G prote in-linked receptors.