Retinoid X receptor alpha, Retinoid X receptor beta, Retinoid X receptor gamma (RXRα, RXRβ, RXRγ)

Retinoid X receptors (RXRα, RXRβ, and RXRγ) are ligand-activated nuclear receptors encoded by three distinct genes, regulating gene transcription by binding DNA in response to specific ligands such as 9-cis retinoic acid. These receptors function either as homodimers or as heterodimeric partners for various other nuclear receptors—including PPAR, RAR, VDR, and more—playing crucial roles in hepatic metabolism, neurobiology, and immune regulation. RXR-targeting drugs such as bexarotene and 9-cis retinoic acid modify gene transcription and are in clinical use or investigation for cancer, metabolic, and neurodegenerative diseases, though adverse effects (like hypothyroidism and metabolic disruption) present challenges for therapy. RXRs remain important and pharmacologically tractable targets within human biological and disease pathways.

Other names

RXR-alphaRXR-betaRXR-gammaRXRARXRBRXRGRetinoid X receptor9-cis retinoic acid receptor

RXR agonists (e.g., bexarotene, 9-cis retinoic acid) bind the ligand-binding domain to induce conformational change, leading to dissociation of corepressors, recruitment of coactivators, and activation of target gene transcription. RXR antagonists (e.g., β-apo-13-carotenone) prevent RXR activation or drive inactive conformations. Heterodimerization with other nuclear receptors modifies ligand selectivity and gene regulation specificity.