<prompt> Thyroid hormone receptors bind to DNA as a heterodimer withProlactin receptorGrowth hormone receptorRetinoid X receptorInsulin receptor  <response>: Thyroid hormone receptors most commonly bind to DNA as a heterodimer with Retinoid X receptor RXR. Mechanism of action of Thyroid Receptors: Thyroid hormone acts by binding to a specific Nuclear Thyroid Receptor TR Nuclear Thyroid Receptor TR in-turn forms a heterodimer with Retinoid X receptor RXR another nuclear receptor Thyroid receptors function primarily by Heterodimerization with Retinoid X receptor RXR The TRRXR Heterodimer then binds to DNA at specific sequences called Thyroid Hormone Response Elements Note that: Thyroid receptors TR may bind to DNA as monomers, homodimers, and heterodimers, but TR binding to DNA is greatly enhanced in response to thyroid hormones when the receptor is in the form of this heterodimer. Retinoid X receptor RXR stays silent and does not bind its natural liagands when it is complexed with Thyroid Receptors The TRRXR heterodimer doesnot bind to 9-cis retinoic acid, the usual ligand for RXR Ref: Ganong 24th edition pgno: 348 