Structural and biochemical mechanisms for the specificity of hormone binding and coactivator assembly by mineralocorticoid receptor.
Mineralocorticoid receptor (MR) controls sodium homeostasis and blood pressure through hormone binding and coactivator recruitment. Here, we report a 1.95 A crystal structure of the MR ligand binding domain containing a single C808S mutation bound to corticosterone and the fourth LXXLL motif of steroid receptor coactivator-1 (SRC1-4). Through a combination of biochemical and structural analyses, we demonstrate that SRC1-4 is the most potent MR binding motif and mutations that disrupt the MR/SRC1-4 interactions abolish the ability of the full-length SRC1 to coactivate MR. The structure also reveals a compact steroid binding pocket with a unique topology that is primarily defined by key residues of helices 6 and 7. Mutations swapping a single residue at position 848 from helix H7 between MR and glucocorticoid receptor (GR) switch their hormone specificity. Together, these findings provide critical insights into the molecular basis of hormone binding and coactivator recognition by MR and related steroid receptors.
Li
Yong
Y
Laboratory of Structural Sciences, Van Andel Research Institute, 333 Bostwick Avenue, Grand Rapids, Michigan 49503, USA.
Suino
Kelly
K
Daugherty
Jennifer
J
Xu
H Eric
HE
D000450:Aldosterone / Q000378:metabolism; D020816:Amino Acid Motifs / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D019556:COS Cells; D002522:Chlorocebus aethiops; D003345:Corticosterone / Q000378:metabolism; D018360:Crystallography, X-Ray; D017930:Genes, Reporter / Q000235:genetics; D051548:Histone Acetyltransferases; D006728:Hormones / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009154:Mutation; D056920:Nuclear Receptor Coactivator 1; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D018161:Receptors, Mineralocorticoid / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011987:Receptors, Steroid / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000235:genetics; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics; D014162:Transfection; D020798:Two-Hybrid System Techniques
D006728:Hormones; D010446:Peptide Fragments; D018161:Receptors, Mineralocorticoid; D011987:Receptors, Steroid; D011994:Recombinant Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D000450:Aldosterone; D051548:Histone Acetyltransferases; C538859:NCOA1 protein, human; D056920:Nuclear Receptor Coactivator 1; D003345:Corticosterone