5Z12 image
Entry Detail
PDB ID:
5Z12
Keywords:
Title:
A structure of FXR/RXR
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2017-12-23
Release Date:
2018-07-04
Method Details:
Experimental Method:
Resolution:
2.75 Å
R-Value Free:
0.29
R-Value Work:
0.22
R-Value Observed:
0.23
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Bile acid receptor
Mutations:C480Q
Chain IDs:A, E (auth: D)
Chain Length:228
Number of Molecules:2
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:Retinoic acid receptor RXR-alpha
Chain IDs:B (auth: C), G (auth: B)
Chain Length:231
Number of Molecules:2
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:Peptide from Nuclear receptor coactivator 2
Chain IDs:C (auth: F), H (auth: I)
Chain Length:9
Number of Molecules:2
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:Peptide from Nuclear receptor coactivator 2
Chain IDs:D (auth: J), F (auth: H)
Chain Length:6
Number of Molecules:2
Biological Source:Homo sapiens
Primary Citation
Structural insights into the heterodimeric complex of the nuclear receptors FXR and RXR
J. Biol. Chem. 293 12535 12541 (2018)
PMID: 29934308 DOI: 10.1074/jbc.RA118.004188

Abstact

Farnesoid X receptor (FXR) is a member of the family of ligand-activated nuclear receptors. FXR plays critical roles in maintaining many metabolic pathways, including bile acid regulation and glucose and lipid homeostasis, and forms a heterodimeric complex with the retinoid X receptor (RXR). Despite the important roles of the FXR/RXR heterodimerization in human physiology, the molecular basis underlying the FXR/RXR interaction is still uncertain in the absence of a complex structure. Here, we report the heterodimeric structure of FXR and RXR in the presence of an FXR agonist (WAY-362450), RXR agonist (9-cis-retinoic acid), and a peptide derived from a steroid receptor coactivator (SRC2), revealing both unique and conserved modes for FXR heterodimerization. We found that the dimerization with RXR induced allosteric conformational changes on the coactivator-binding site of FXR. These changes enhanced the transcriptional activity of FXR by promoting the coactivator binding, thus suggesting a structural basis for the functional permissiveness of the FXR/RXR heterodimer complex. Furthermore, sequence analyses together with functional mutagenesis studies indicated that the helix H10 largely responsible for the dimerization is highly conserved and also critical for the FXR transcriptional activity. Our findings highlight the important roles of RXR heterodimerization in the nuclear receptor signaling, providing a potential framework to develop pharmaceutical agents in treating FXR/RXR-related diseases.

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