G-PROTEIN-COUPLED-RECEPTOR CROSS-TALK - THE FINE-TUNING OF MULTIPLE RECEPTOR-SIGNALING PATHWAYS

Signalling via the large family of G protein-coupled receptors (GPCRs) can lead to many cellular responses, ranging from regulation of intra cellular levels of cAMP to stimulation of gene transcription. Members of this receptor family have been grouped into different categories de pendent on the particular G protein subtypes that they predominantly i nteract with. Thus, receptors that couple to G(S) proteins will stimul ate adenylate cyclase in many cells, while G(q/1)-coupled receptors ca n mobilize intracellular Ca2+ via activation of phospholipase C. There is accumulating evidence, however, that activation of one particular signalling pathway by a GPCR can amplify intracellular signalling with in a parallel but separate pathway. In this article Lisa Selbie and St ephen Hill review some of the evidence for these synergistic interacti ons and suggest that they may have an important role in fine-tuning si gnals from multiple receptor signalling pathways.