Dynamic stabilization of nuclear receptor ligand binding domains by hormone or corepressor binding.
We have developed a novel assembly assay to examine structural changes in the ligand binding domain (LBD) of the thyroid hormone receptor (TR). Fragments including the first helix of the TR LBD interact only weakly with the remainder of the LBD in the absence of hormone, but this interaction is strongly enhanced by the addition of either hormone or the corepressor NCoR. Since neither the ligand nor the corepressor shows direct interaction with this helix, we propose that both exert their effects by stabilizing the overall structure of the LBD. Current models of activation of nuclear hormone receptors focus on a ligand-induced allosteric shift in the position of the C-terminal helix 12 that generates the coactivator binding site. Our results suggest that ligand binding also has more global effects that dynamically alter the structure of the receptor LBD.
Pissios
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Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
Tzameli
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Kushner
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Moore
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D000595:Amino Acid Sequence; D001665:Binding Sites; D002460:Cell Line; D047628:Estrogen Receptor alpha; D006801:Humans; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D056971:Nuclear Receptor Co-Repressor 1; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary; D011960:Receptors, Estrogen / Q000737:chemistry* / Q000378:metabolism; D018168:Receptors, Retinoic Acid / Q000737:chemistry* / Q000378:metabolism; D011988:Receptors, Thyroid Hormone / Q000737:chemistry* / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D000072482:Retinoic Acid Receptor alpha; D047488:Retinoid X Receptors; D017384:Sequence Deletion; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism; D014162:Transfection
D047628:Estrogen Receptor alpha; D008024:Ligands; C539127:NCOR1 protein, human; D009687:Nuclear Proteins; D056971:Nuclear Receptor Co-Repressor 1; D010446:Peptide Fragments; C000607071:RARA protein, human; D011960:Receptors, Estrogen; D018168:Receptors, Retinoic Acid; D011988:Receptors, Thyroid Hormone; D011994:Recombinant Proteins; D012097:Repressor Proteins; D000072482:Retinoic Acid Receptor alpha; D047488:Retinoid X Receptors; D014157:Transcription Factors