Advances in signalling by extracellular nucleotides: the role and transduction mechanisms of P2Y receptors

Nucleotides are ubiquitous intercellular messengers whose actions are mediated by specific receptors. Since the first clonings in 1993, it is known that nucleotide receptors belong to two families: the ionotropic P2X receptors and the metabotropic P2Y receptors. Five human P2Y receptor subtypes have been cloned so far and a sixth one must still be isolated. In this review we will show that they differ by their preference for adenine ver-sits uracil nucleotides and triphospho versus diphospho nucleotides, as well as by their transduction mechanisms and cell expression. (C) 2000 Elsevier Science Inc. All rights reserved.