tailieunhanh - Báo cáo khoa học: Membrane compartments and purinergic signalling: the purinome, a complex interplay among ligands, degrading enzymes, receptors and transporters

Receptors should be properly analysed in view of the microenvironment in which they are embedded. Therefore, the concept of ‘receptosome’ was for-mulated to the complex interactions taking place between receptors and other proteins at the plasma membrane level, and to explain very heteroge-neous or divergent cellular responses to common epigenetic factors and modifications to the extracellular environment. | MINIREVIEW Membrane compartments and purinergic signalling the purinome a complex interplay among ligands degrading enzymes receptors and transporters Cinzia Volonté and Nadia D Ambrosi Santa Lucia Foundation CNR Rome Italy Keywords CNS ectonucleotide metabolizing enzymes ectonucleoside transporters extracellular nucleotides lung nucleotide release P1 receptors protein cooperation P2X receptors P2Y receptors Correspondence C. Volonte Santa Lucia Foundation CNR Via delFosso di Fiorano 65 00143 Rome Italy Fax 39 06 501 703321 Tel 39 06 501 703084 E-mail Received 15 July 2008 revised 9 October 2008 accepted 12 November 2008 doi Receptors should be properly analysed in view of the microenvironment in which they are embedded. Therefore the concept of receptosome was formulated to the complex interactions taking place between receptors and other proteins at the plasma membrane level and to explain very heterogeneous or divergent cellular responses to common epigenetic factors and modifications to the extracellular environment. The receptosome thus becomes a molecular network connecting transmitters hormones or growth factors to both their specific receptors and unique downstream effector proteins. As an example of receptosome we introduce here the purinome as molecular complex responsible for the biological effects of extracellular purine and pyrimidine ligands. In addition to a vast heterogeneity of puri-nergic ligands the purinome thus consists of ectonucleotide-metabolizing enzymes hydrolysing nucleoside phosphates purinergic receptors classified as P1 for adenosine AMP and P2 for nucleosides tri- diphosphates nucleoside transporters with both equilibrative and concentrative properties and finally nucleotide channels and transporters. Notably these purinergic elements are not independent but they play tightly concerted actions under physiological conditions. As a whole and not singularly they trigger maintain