| Abstract: | G protein-coupled receptors (GPCRs) are by far the most successful drug targets yet known, due to their key role in cellular communication. Historically, these drugs bind to the same site at which the endogenous agonist interacts. However, as the details of cell signalling are clarified, it is becoming apparent that there are many other sites at which GPCR signalling can be modulated. Furthermore, the emerging ability to block protein-protein interactions with small molecules means that these sites are now also viable therapeutic targets. Potential points of therapeutic intervention of GPCR signalling are at the level of the G protein, where the activities of both a and βγ subunits could be controlled; at multiple effectors such as the adenylyl cyclases, phospholipases and phosphodiesterases; at regulatory proteins such as the regulators of G protein signalling (RGS) proteins or receptor kinases; or at the mitogenic pathways, which offer many sites for intervention. By targeting these sites, perhaps just one arm of the multiple pathways through which a receptor works can be modified, thus providing a greater degree of therapeutic selectivity and specificity than can be attained using receptor agonists or antagonists. |
