title: A Natural Mutation in Helix 5 of the Ligand Binding Domain of Glucocorticoid Receptor Enhances Receptor-Ligand Interaction.
abstract: The glucocorticoid receptor (GR) is a central player in the neuroendocrine stress response; it mediates feedback regulation of the hypothalamus-pituitary-adrenal (HPA) axis and physiological actions of glucocorticoids in the periphery. Despite intensive investigations of GR in the context of receptor-ligand interaction, only recently the first naturally occurring gain-of-function substitution, Ala610Val, of the ligand binding domain was identified in mammals. We showed that this mutation underlies a major quantitative trait locus for HPA axis activity in pigs, reducing cortisol production by about 40-50 percent. To unravel the molecular mechanisms behind this gain of function, receptor-ligand interactions were evaluated in silico, in vitro and in vivo. In accordance with previously observed phenotypic effects, the mutant Val610 GR showed significantly increased activation in response to glucocorticoid and non-glucocorticoid steroids, and, as revealed by GR-binding studies in vitro and in pituitary glands, enhanced ligand binding. Concordantly, the protein structure prediction depicted reduced binding distances between the receptor and ligand, and altered interactions in the ligand binding pocket. Consequently, the Ala610Val substitution opens up new structural information for the design of potent GR ligands and to examine effects of the enhanced GR responsiveness to glucocorticoids on the entire organism.
authors.affiliation: Institute for Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany.
authors.forename: Henry
authors.initials: H
authors.lastname: Reyer
authors.affiliation: Institute for Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany.
authors.forename: Siriluck
authors.initials: S
authors.lastname: Ponsuksili
authors.affiliation: Institute of Behavioural Physiology, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany.
authors.forename: Ellen
authors.initials: E
authors.lastname: Kanitz
authors.affiliation: Institute of Reproductive Biology, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Pöhland
authors.affiliation: Institute for Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Wimmers
authors.affiliation: Institute for Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany.
authors.forename: Eduard
authors.initials: E
authors.lastname: Murani
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D002522:Chlorocebus aethiops; D003907:Dexamethasone / Q000494:pharmacology; D006854:Hydrocortisone / Q000378:metabolism*; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism*; D008024:Ligands; D008958:Models, Molecular; D009154:Mutation; D010913:Pituitary-Adrenal System / Q000378:metabolism*; D011485:Protein Binding; D017433:Protein Structure, Secondary; D011965:Receptors, Glucocorticoid / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013552:Swine
chemical_list: D008024:Ligands; D011965:Receptors, Glucocorticoid; D003907:Dexamethasone; D006854:Hydrocortisone