Molecular origins for the dominant negative function of human glucocorticoid receptor beta.
This study molecularly elucidates the basis for the dominant negative mechanism of the glucocorticoid receptor (GR) isoform hGRbeta, whose overexpression is associated with human glucocorticoid resistance. Using a series of truncated hGRalpha mutants and sequential mutagenesis to generate a series of hGRalpha/beta hybrids, we find that the absence of helix 12 is neither necessary nor sufficient for the GR dominant negative phenotype. Moreover, we have localized the dominant negative activity of hGRbeta to two residues and found that nuclear localization, in addition to heterodimerization, is a critical feature of the dominant negative activity. Molecular modeling of wild-type and mutant hGRalpha and hGRbeta provides structural insight and a potential physical explanation for the lack of hormone binding and the dominant negative actions of hGRbeta.
Yudt
Matthew R
MR
Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
Jewell
Christine M
CM
Bienstock
Rachelle J
RJ
Cidlowski
John A
JA
D000465:Algorithms; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D019556:COS Cells; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D015500:Chloramphenicol O-Acetyltransferase / Q000378:metabolism; D018360:Crystallography, X-Ray; D004247:DNA / Q000378:metabolism; D019281:Dimerization; D004351:Drug Resistance; D005799:Genes, Dominant; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D011965:Receptors, Glucocorticoid / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D015533:Transcriptional Activation; D014162:Transfection
D008024:Ligands; D020033:Protein Isoforms; D011965:Receptors, Glucocorticoid; C411470:glucocorticoid receptor alpha; C121943:glucocorticoid receptor beta; D004247:DNA; D015500:Chloramphenicol O-Acetyltransferase; D005982:Glutathione Transferase