NF-YC functions as a corepressor of agonist-bound mineralocorticoid receptor.
The role of aldosterone has been implicated in the metabolic syndrome and cardiovascular diseases. The biological actions of aldosterone are mediated through mineralocorticoid receptor (MR). Nuclear receptor-mediated gene expression is regulated by dynamic and coordinated recruitment of coactivators and corepressors. To identify new coregulators of the MR, full-length MR was used as bait in yeast two-hybrid screening. We isolated NF-YC, one of the subunits of heterotrimeric transcription factor NF-Y. Specific interaction between MR and NF-YC was confirmed by yeast two-hybrid, mammalian two-hybrid, coimmunoprecipitation assays, and fluorescence subcellular imaging. Transient transfection experiments in COS-7 cells demonstrated that NF-YC repressed MR transactivation in a hormone-sensitive manner. Moreover, reduction of NF-YC protein levels by small interfering RNA potentiated hormonal activation of endogenous target genes in stably MR-expressing cells, indicating that NF-YC functions as an agonist-dependent MR corepressor. The corepressor function of NF-YC is selective for MR, because overexpression of NF-YC did not affect transcriptional activity mediated by androgen, progesterone, or glucocorticoid receptors. Chromatin immunoprecipitation experiments showed that endogenous MR and steroid receptor coactivator-1 were recruited to an endogenous ENaC gene promoter in a largely aldosterone-dependent manner, and endogenous NF-YC was sequentially recruited to the same element. Immunohistochemistry showed that endogenous MR and NF-YC were colocalized within the mouse kidney. Although aldosterone induces interaction of the N and C termini of MR, NF-YC inhibited the N/C interaction. These findings indicate that NF-YC functions as a new corepressor of agonist-bound MR via alteration of aldosterone-induced MR conformation.
Murai-Takeda
Ayano
A
Department of Internal Medicine, School of Medicine, Keio University, Tokyo 160-8582, Japan.
Shibata
Hirotaka
H
Kurihara
Isao
I
Kobayashi
Sakiko
S
Yokota
Kenichi
K
Suda
Noriko
N
Mitsuishi
Yuko
Y
Jo
Rie
R
Kitagawa
Hirochika
H
Kato
Shigeaki
S
Saruta
Takao
T
Itoh
Hiroshi
H
D000450:Aldosterone / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D023081:CCAAT-Binding Factor / Q000378:metabolism*; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D004305:Dose-Response Relationship, Drug; D053503:Epithelial Sodium Channels / Q000378:metabolism; D006655:Histone Deacetylases / Q000378:metabolism; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism* / Q000494:pharmacology; D007150:Immunohistochemistry; D007685:Kidney Tubules, Collecting / Q000166:cytology / Q000378:metabolism*; D008297:Male; D051379:Mice; D011401:Promoter Regions, Genetic / Q000502:physiology; D017434:Protein Structure, Tertiary; D011944:Receptors, Androgen / Q000378:metabolism; D011965:Receptors, Glucocorticoid / Q000378:metabolism; D018161:Receptors, Mineralocorticoid / Q000819:agonists / Q000737:chemistry / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism; D020798:Two-Hybrid System Techniques
D023081:CCAAT-Binding Factor; D053503:Epithelial Sodium Channels; C469358:NFYC protein, human; D011944:Receptors, Androgen; D011965:Receptors, Glucocorticoid; D018161:Receptors, Mineralocorticoid; D011980:Receptors, Progesterone; D000450:Aldosterone; D006655:Histone Deacetylases; D006854:Hydrocortisone