Orphan Nuclear Receptors: From Gene to Function*

Abstract

I. Introduction II. Nuclear Receptors: General Concepts A. Anatomyof nuclear receptors B. Mechanisms of action III. Orphan NuclearReceptors A. Definition B. Nomenclature C. Structural and functionaldiversity IV. Novel Hormone Response Systems: RXR and Its HeterodimericPartners A. RXR: rexinoids B. PPAR: multiple ligands, multiple functionsC. PXR: pregnanes, xenobiotic compounds, and benzoate derivativesD. CAR (constitutive androstane receptor): androstanes and phenobarbitalE. LXR: control of cholesterol metabolism by oxysterols F. FXR: bileacids receptor V. Orphans in Search of a Home A. HNF4: diabetes andpossible regulation by acyl-coenzyme A (CoA) thioesters B. FTZ-F1:steroidogenesis and sexual development C. Rev-Erb: singular membersof the superfamily D. ROR: neuron development and T cell selectionE. TR2: the testis receptors F. TLX: forebrain development G. COUP-TF:neurogenesis, angiogenesis, and heart development H. ERR: placentadevelopment and control of lipid metabolism I. NGFI-B: hypothalamus-pituitaryaxis (HPA), T cells, and dopaminergic neurons J. GCNF: one of a kindK. DAX-1: adrenal development and sex determination L. SHP: a promiscuousand inhibitory heterodimeric partner VI. Concluding Remarks