Dataset Information

Structural basis for heme-dependent NCoR binding to the transcriptional repressor REV-ERBβ

ABSTRACT: Heme is the endogenous ligand for the constitutively repressive REV-ERB nuclear receptors, REV-ERBα (NR1D1) and REV-ERBβ (NR1D2), but how heme regulates REV-ERB activity remains unclear. While cellular studies indicate heme is required for the REV-ERBs to bind the corepressor NCoR and repress transcription, fluorescence-based biochemical assays and crystal structures suggest that heme displaces NCoR. Here, we found that heme artifactually influences detection of NCoR interaction in fluorescence-based assays. Using fluorescence-independent methods, including isothermal titration calorimetry, NMR spectroscopy, and XL-MS, we determined that heme remodels the thermodynamic profile of NCoR binding to REV-ERBβ ligand-binding domain (LBD) and directly increases LBD binding affinity for an NCoR interaction motif. We further report two crystal structures of REV-ERBβ LBD cobound to heme and NCoR peptides, which reveal the heme-dependent NCoR binding mode. By resolving previous contradictory biochemical, structural, and cellular studies, our findings should facilitate renewed progress toward understanding heme-dependent REV-ERB activity.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Mus Musculus (mouse)

SUBMITTER: Timothy Strutzenberg

LAB HEAD: Patrick Robert Griffin

PROVIDER: PXD021761 | Pride | 2021-02-24

REPOSITORIES: Pride

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Publications

Structural basis for heme-dependent NCoR binding to the transcriptional repressor REV-ERBβ.

Mosure Sarah A SA Strutzenberg Timothy S TS Shang Jinsai J Munoz-Tello Paola P Solt Laura A LA Griffin Patrick R PR Kojetin Douglas J DJ

Science advances 20210127 5

Heme is the endogenous ligand for the constitutively repressive REV-ERB nuclear receptors, REV-ERBα (NR1D1) and REV-ERBβ (NR1D2), but how heme regulates REV-ERB activity remains unclear. Cellular studies indicate that heme is required for the REV-ERBs to bind the corepressor NCoR and repress transcription. However, fluorescence-based biochemical assays suggest that heme displaces NCoR; here, we show that this is due to a heme-dependent artifact. Using ITC and NMR spectroscopy, we show that heme ...[more]

PMID: 33571111

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Project description:Sample preparation: P-AMPK+AMP, P-AMPK+ATPγS, and AMPK+ATPγS protein samples were crosslinked in HBST buffer (25 mM HEPES pH 7.5 at room temperature, 200 mM NaCL, and 1 mM TCEP). Non-crosslinked negative controls were generated using the same procedure without the addition of DSSO. Reactions were initiated by spiking 1 uL of 75 mM DSSO (Thermo-Fisher) in DMSO into a 50 uL solution containing 10 uM protein and mixing. The final molar ratio of crosslinker:protein was 150:1. The reactions were incubated at 25°C for 45 minutes prior to being quenched by the addition of Tris pH 8.0 to a final concentration of 50 mM. Each crosslink reaction was done in triplicate and the reaction replicates were pooled after quenching. 10 μL samples of the pooled samples were loaded for SDS-PAGE analysis with Coomassie staining to confirm the presence of crosslinked protein. The remaining 140 μL of crosslinked and non-crosslinked samples were then acetone precipitated at -20°C overnight and the protein was pelleted by centrifugation at 16,000 rcf for 5 minutes at 4°C. After decanting, the pellets were dried for 15 minutes at room temperature before being resuspended in 12.5 uL of resuspension buffer (50 mM ammonium bicarbonate, 8M urea, pH 8.0). ProteaseMAX (Promega) was added to 0.02% and the solutions were mixed on an orbital shaker operating at 400 RPM for 5 minutes. After resuspension, 87.5 uL of digestion buffer (50 mM ammonium bicarbonate, pH 8.0) was added. Cysteines in the protein samples were reduced and akylated as follows. DTT was added to 5 mM final concentration and the protein solutions were incubated at 56°C in an orbital shaker operating at 400 RPM and for 20 minutes. After reduction, 2.7 uL of 550 mM iodoacetamide was added and the solutions were incubated in the dark at room temperature for 15 minutes. Reduced and alkylated protein solutions were digested using trypsin at a ratio of 1:200 (w/w trypsin:protein) and incubating at 37°C. After overnight incubation at 37°C, the samples were acidified by the addition of trifluoroacetic acid (TFA, Thermo-Fischer) to 1%. Samples were then frozen and stored at -20°C until analysis.

Dataset Information

Structural basis for heme-dependent NCoR binding to the transcriptional repressor REV-ERBβ

Publications

Structural basis for heme-dependent NCoR binding to the transcriptional repressor REV-ERBβ.

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