Enhances the transcriptional activities of several nuclear receptors. Involved in the coactivation of different nuclear receptors, such as ESR1, THRB, PPARG and RARA (By similarity). Interacts with ESR1, ESR2A, ESR2B, THRB, PPARG and RARA in a ligand-inducible manner. Interacts with the heterodimer AHR-ARNT (By similarity). Highly expressed in brain and kidney. Weakly expressed in mammary gland, lung and testis. In brain, expression is found in neurons of cerebral cortex, thalamus, hypothalamus, hippocampus, cerebellum, striatum and choroid plexus. Belongs to the OXR1 family.