Nuclear-receptor ligands and ligand-binding domains

The determination of several structures of nuclear receptor ligand binding domains (LBD) has led to new insights into the mechanism of action of this very important class of receptors. This review describes and compares the d ifferent LED structures and their relationship to the function of the nucle ar receptors. The role of the ligand in the LED structures and the implicat ions of ligand structure on receptor activity are also discussed. Structura l information regarding interactions between the LED and coactivator protei ns and the potential role of these interactions in ligand agonism and antag onism is reviewed. Different pathways for nuclear receptor signaling and th e use of new ligands to investigate these pathways are also described.