Pregnane X receptor (PXR) is a Nuclear receptor which senses the presence of toxic substances and regulates the expression of proteins which are involved in detoxificaton. PXR is activated by a large range of steroids, antibiotics, bile acids and many herbal compounds. Thus it is a generalized sensor of hydrophobic toxins. When activated, PXR binds to the retinoid X receptor (RXR) and the formed heterodimer binds to hormone response elements on the DNA. PXR, similar to other nuclear receptors contains a ligand-binding domain (LBD) and DNA-binding domain (DBD).
