Nuclear receptors are ligand-dependent transcription factors.
Reference: Burris_2012_Chem Biol;
In contrast to extracellular receptors such as the insulin receptor, intracellular receptors directely bind endocrine hormones and dietary lipids. Nuclear receptors interact directly with lipophilic ligands and bind to specific DNA response elements to regulate expression of target genes. They include receptors for steroid hormones, thyroid hormone, various lipids and oxysterols. Nuclear receptors are promising drug targets for diseases such as inflammation, cancer, and metabolic disorders. All nuclear receptor members have a similar canonical domain structure that includes an N-terminal activation domain and conserved DNA and ligand-binding domains. Well known members of the nuclear-receptor superfamily include the three different ligand-activated peroxisome proliverator activated receptor (PPAR) subtypes, PPAR-α, PPAR-β/δ, and PPAR-γ or the retinoid X receptor (RXR).