The retinoid X receptor (RXR)[1] is a type of nuclear receptor that is activated by 9-cis retinoic acid, which is discussed controversially to be of endogenous relevance,[2][3] and 9-cis-13,14-dihydroretinoic acid, which may be an endogenous mammalian RXR-selective agonist.
[5] There are three retinoic X receptors (RXR): RXR-alpha, RXR-beta, and RXR-gamma, encoded by the RXRA, RXRB, RXRG genes, respectively.
RXR heterodimerizes with multiple nuclear receptors including CAR, FXR, LXR, PPAR,[6] PXR, RAR, TR, ER and VDR.
RXRs are permissive co-receptors as only one of six alleles is needed for normal development and health.
As with other type II nuclear receptors, the RXR heterodimer in the absence of ligand is bound to hormone response elements complexed with corepressor protein.