Modeling of G protein-coupled receptors using crystal structures: from monomers to signaling complexes.

G protein-coupled receptors constitute a large and functionally diverse family of transmembrane proteins. They are fundamental in the transfer of extracellular stimuli to intracellular signaling pathways and are among the most targeted proteins in drug discovery. Recent advances in crystallization methods have permitted to resolve the molecular structure of several members of the family. This chapter focuses on the impact of these structures in the use of homology modeling techniques for building three-dimensional models of homologous G protein-coupled receptors, higher order oligomers, and their complexes with ligands and signaling proteins.