Chemogenomic approaches for the exploration of GPCR space.

The potential areas of applications of chemogenomic approaches are very large. Thanks to the large amount of knowledge accumulated during years of research, it is now possible to consider the binding of a ligand to a protein in a much larger context. This knowledge combined with the augmentation of computing capabilities allows global approaches to investigate biological and pharmaceutical problems. Classification of proteins, focused libraries, selectivity profiles and elaboration of new ligands for orphan receptors can all be investigated using chemogenomic. G protein-coupled receptors (GPCRs) constitute a large protein family of significant interest in pharmaceutical research. Despite this interest, and excluding the more than 360 nonolfatory proteins, the endogenous ligands of about 100 GPCRs have still not been identified. The main limitation of GPCRs investigation is the lack of 3D structures. The goal of this review is to present different chemogenomic approaches that can be applied to GPCRs. Three types of such approaches are presented: ligand centered, protein centered and protein-ligand centered approaches. For each of them, current limitations and biases are mentioned.