1osv | pdb_00001osv
STRUCTURAL BASIS FOR BILE ACID BINDING AND ACTIVATION OF THE NUCLEAR RECEPTOR FXR
Structural highlights
Function[NR1H4_RAT] Ligand-activated transcription factor. Receptor for bile acids such as chenodeoxycholic acid, lithocholic acid and deoxycholic acid. Represses the transcription of the cholesterol 7-alpha-hydroxylase gene (CYP7A1) and activates the intestinal bile acid-binding protein (IBABP). Activates the transcription of bile salt export pump ABCB11 by directly recruiting histone methyltransferase CARM1 within its gene locus (By similarity). [NCOA2_MOUSE] Transcriptional coactivator for steroid receptors and nuclear receptors. Coactivator of the steroid binding domain (AF-2) but not of the modulating N-terminal domain (AF-1). Required with NCOA1 to control energy balance between white and brown adipose tissues.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe nuclear receptor FXR is the sensor of physiological levels of enterohepatic bile acids, the end products of cholesterol catabolism. Here we report crystal structures of the FXR ligand binding domain in complex with coactivator peptide and two different bile acids. An unusual A/B ring juncture, a feature associated with bile acids and no other steroids, provides ligand discrimination and triggers a pi-cation switch that activates FXR. Helix 12, the activation function 2 of the receptor, adopts the agonist conformation and stabilizes coactivator peptide binding. FXR is able to interact simultaneously with two coactivator motifs, providing a mechanism for enhanced binding of coactivators through intermolecular contacts between their LXXLL sequences. These FXR complexes provide direct insights into the design of therapeutic bile acids for treatment of hyperlipidemia and cholestasis. Structural basis for bile acid binding and activation of the nuclear receptor FXR.,Mi LZ, Devarakonda S, Harp JM, Han Q, Pellicciari R, Willson TM, Khorasanizadeh S, Rastinejad F Mol Cell. 2003 Apr;11(4):1093-100. PMID:12718893[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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