Mechanism of the nuclear receptor molecular switch.

Nuclear receptors are central to the regulation of development, endocrine signalling and metabolism. The transcriptional activity of many receptors is controlled through the binding of small, fat-soluble molecules to the ligand-binding domain. In most cases, ligand binding turns the receptors into potent activators of transcription. This switch involves the exchange of co-regulator proteins that mediate transcriptional regulation. Structural and biochemical studies have together revealed the mechanism of action of this ligand-induced molecular switch, in which changes in the dynamic behaviour of the receptor play a key role. This remarkable dynamic mechanism has facilitated the evolution of a family of nuclear receptors with highly diverse ligand recognition and signalling properties.