All-trans retinoic acid is a ligand for the orphan nuclear receptor ROR beta.

Retinoids regulate gene expression through binding to the nuclear retinoic acid receptors (RARs) and retinoid X receptors (RXRs). In contrast, no ligands for the retinoic acid receptor-related orphan receptors beta and gamma (ROR beta and gamma) have been identified, yet structural data and structure-function analyses indicate that ROR beta is a ligand-regulated nuclear receptor. Using nondenaturing mass spectrometry and scintillation proximity assays we found that all-trans retinoic acid (ATRA) and several retinoids bind to the ROR beta ligand-binding domain (LBD).