title: Restored mutant receptor:Corticoid binding in chaperone complexes by trimethylamine N-oxide.
abstract: Without a glucocorticoid (GC) ligand, the transcription factor glucocorticoid receptor (GR) is largely cytoplasmic, with its GC-binding domain held in high affinity conformation by a cluster of chaperones. Binding a GC causes serial dis- and re-associations with chaperones, translocation of the GR to the nucleus, where it binds to DNA sites and associates with coregulatory proteins and basic transcription complexes. Herein, we describe the effects of a potent protective osmolyte, trimethylamine N-oxide (TMAO), on a conditions-dependent "activation-labile" mutant GR (GRact/l), which under GR-activating conditions cannot bind GCs in cells or in cell cytosols. In both cells and cytosols, TMAO restores binding to GRact/l by stabilizing it in complex with chaperones. Cells bathed in much lower concentrations of TMAO than those required in vitro show restoration of GC binding, presumably due to intracellular molecular crowding effects.
authors.affiliation: Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors.forename: Aaron L
authors.initials: AL
authors.lastname: Miller
authors.affiliation: Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors.forename: W Austin
authors.initials: WA
authors.lastname: Elam
authors.affiliation: Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors.forename: Betty H
authors.initials: BH
authors.lastname: Johnson
authors.affiliation: Department of Basic Sciences, Geisinger Commonwealth School of Medicine, Scranton, Pennsylvania, United States of America.
authors.forename: Shagufta H
authors.initials: SH
authors.lastname: Khan
authors.affiliation: Department of Basic Sciences, Geisinger Commonwealth School of Medicine, Scranton, Pennsylvania, United States of America.
authors.forename: Raj
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors.forename: E Brad
authors.initials: EB
authors.lastname: Thompson
mesh_terms: D000305:Adrenal Cortex Hormones / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D006801:Humans; D008744:Methylamines / Q000378:metabolism*; D018832:Molecular Chaperones / Q000378:metabolism*; D011485:Protein Binding; D011965:Receptors, Glucocorticoid / Q000235:genetics / Q000378:metabolism*
chemical_list: D000305:Adrenal Cortex Hormones; D008744:Methylamines; D018832:Molecular Chaperones; D011965:Receptors, Glucocorticoid; C005855:trimethyloxamine