HORMONE BINDING TO THE THYROID HORMONE RECEPTOR. R. Fletterick, R., Wagner, J. Baxter, A. Shiau, J. Apriletti. University of California, San Francisco, Dept. of Biochemistry/Biophysics, 513 Parnassus Avenue, San Francisco, CA 94143-0448, USA

This receptor is a central metabolic regulator and is a member of the family of nuclear receptors that regulate transcription of responsive genes. The structures of two isoforms [[alpha]] and [[beta]] were determined to understand the mechanism of recognition of hormone and the changing relationship of the receptor to its receptor, repressor and activator partners. The ligand binding domain (LBD) of the receptor comprises 12 helices and employs the hormone as a component of the hydrophobic core of the domain. The structures of the LBD with hormone and hormone analogs suggest means for precise recognition. The LBD can form dimers with homologs of the receptor or homodimers. The structures of two different homodimers have been determined to learn whether the means of association is used in transcriptional control.