Ligand-induced stabilization of PPARgamma monitored by NMR spectroscopy: implications for nuclear receptor activation.
J Mol Biol
; 298(2): 187-94, 2000 Apr 28.
Article
en En
| MEDLINE
| ID: mdl-10764590
ABSTRACT
Nuclear receptors are ligand-dependent transcription factors that are mediators of the action of lipophilic hormones and other endogenous ligands and are the targets of drugs useful in a variety of therapeutic areas. Peroxisome proliferator-activated receptor (PPAR)gamma is a nuclear receptor that, acting as a heterodimer with RXR, mediates a variety of cellular effects including adipocyte-differentiation. Due to its role in modulating insulin sensitivity, it is the target of therapeutically active anti-diabetic agents such as rosiglitazone. We have assigned the chemical shifts of the backbone atoms of the 32 kDa ligand-binding domain of PPARgamma in the presence of bound rosiglitazone. Three-dimensional HNCO spectra of the apo ligand-binding domain (LBD) have less than half the expected number of cross-peaks. The missing cross-peaks are restored upon binding strong agonists such as rosiglitazone. The NMR results indicate that the apo-LBD of PPARgamma is in a conformationally mobile state, and that agonist binding is associated with a marked stabilization of the conformation. Mapping the missing peaks to the 3D X-ray crystallographic structure indicates the region of mobility is extensive and includes the ligand-binding region and the cofactor-binding site. This leads to the conclusion that activation of this nuclear receptor is a result of a population shift of a dynamic ensemble of conformations, rather than a two-state switch from an inactive to an active conformation. Our results have important implications for the mechanisms by which antagonists, partial agonists, and agonists of nuclear receptor function operate.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Factores de Transcripción
/
Receptores Citoplasmáticos y Nucleares
/
Resonancia Magnética Nuclear Biomolecular
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
J Mol Biol
Año:
2000
Tipo del documento:
Article
País de afiliación:
Estados Unidos