Chapter 3 Molecular biology of P2Y receptors expressed in the nervous system

Abstract

Since the cloning of the first two members of the P2Y receptor family—the P2Y 1 and P2Y 2 receptors—a number of related sequences have been isolated from species ranging from Xenopus laevis to Homo sapiens . On the basis of sequence analysis alone 12 subtypes of P2Y receptor have been proposed across these species boundaries. This family of receptors can be divided into four subtypes: the adenine nucleotide specific receptors, P2Y 1 and P2Y 11 ; the uridine nucleotide preferring receptors, P2Y 3 and P2Y 6 ; those at which both UTP and ATP are highly active, P2Y 2 and P2Y 4; and finally those which are activated by all triphosphate nucleotides, xlp2y and tp2y. At least two further subtypes of P2Y receptor have yet to be identified at the molecular level. The first of these has long been known as the “P2T receptor,” most extensively characterized on platelets. The second is the “P2D” receptor activated by diadenosine polyphosphates.