Nuclear receptors

 Nuclear receptors are intracellular receptors, found in either in the cytosol or in the nucleus, bind ligands such as steroid hormones, thyroid hormones and fat-soluble vitamin A and vitamin D .

Binding of the ligand causes a conformational change in the receptor resulting in the dissociation of chaperone proteins from the receptor to reveal sequence specific binding sites. This increases its affinity of the nuclear-receptor complex for the specific chromosome binding site. Contrastingly, ligand binding can also act as a transcription repressor. Thus, nuclear receptors, along with their ligands work to regulate transcription and gene expression.