The ligand binding domain of Retinoid-related orphan receptors, of the nuclear receptor superfamily
The ligand binding domain (LBD) of Retinoid-related orphan receptors (RORs): Retinoid-related orphan receptors (RORs) are transcription factors belonging to the nuclear receptor superfamily. RORs are key regulators of many physiological processes during embryonic development. RORs bind as monomers to specific ROR response elements (ROREs) consisting of the consensus core motif AGGTCA preceded by a 5-bp A/T-rich sequence. Transcription regulation by RORs is mediated through certain corepressors, as well as coactivators. There are three subtypes of retinoid-related orphan receptors (RORs), alpha, beta, and gamma that differ only in N-terminal sequence and are distributed in distinct tissues. RORalpha plays a key role in the development of the cerebellum, particularly in the regulation of the maturation and survival of Purkinje cells. RORbeta expression is largely restricted to several regions of the brain, the retina, and pineal gland. RORgamma is essential for lymph node organogenesis. Recently, it has been su ggested that cholesterol or a cholesterol derivative is the natural ligand of RORalpha. Like other members of the nuclear receptor (NR) superfamily of ligand-activated transcription factors, retinoid-related orphan receptors have a central well conserved DNA binding domain (DBD), a variable N-terminal domain, a non-conserved hinge and a C-terminal ligand binding domain (LBD).