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Nat Struct Mol Biol. 2007 Dec;14(12):1207-13. Epub 2007 Nov 25.

Identification of heme as the ligand for the orphan nuclear receptors REV-ERBalpha and REV-ERBbeta.

Author information

1
Department of Pharmacology and Center for Molecular Design, University of Virginia Health System, 1300 Jefferson Park Avenue, Charlottesville, Virginia 22908-0733, USA.

Abstract

The nuclear receptors REV-ERBalpha (encoded by NR1D1) and REV-ERBbeta (NR1D2) have remained orphans owing to the lack of identified physiological ligands. Here we show that heme is a physiological ligand of both receptors. Heme associates with the ligand-binding domains of the REV-ERB receptors with a 1:1 stoichiometry and enhances the thermal stability of the proteins. Results from experiments of heme depletion in mammalian cells indicate that heme binding to REV-ERB causes the recruitment of the co-repressor NCoR, leading to repression of target genes including BMAL1 (official symbol ARNTL), an essential component of the circadian oscillator. Heme extends the known types of ligands used by the human nuclear receptor family beyond the endocrine hormones and dietary lipids described so far. Our results further indicate that heme regulation of REV-ERBs may link the control of metabolism and the mammalian clock.

PMID:
18037887
PMCID:
PMC2743565
DOI:
10.1038/nsmb1344
[Indexed for MEDLINE]
Free PMC Article

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