title: Structural basis for antagonist-mediated recruitment of nuclear co-repressors by PPARalpha.
abstract: Repression of gene transcription by nuclear receptors is mediated by interactions with co-repressor proteins such as SMRT and N-CoR, which in turn recruit histone deacetylases to the chromatin. Aberrant interactions between nuclear receptors and co-repressors contribute towards acute promyelocytic leukaemia and thyroid hormone resistance syndrome. The binding of co-repressors to nuclear receptors occurs in the unliganded state, and can be stabilized by antagonists. Here we report the crystal structure of a ternary complex containing the peroxisome proliferator-activated receptor-alpha ligand-binding domain bound to the antagonist GW6471 and a SMRT co-repressor motif. In this structure, the co-repressor motif adopts a three-turn alpha-helix that prevents the carboxy-terminal activation helix (AF-2) of the receptor from assuming the active conformation. Binding of the co-repressor motif is further reinforced by the antagonist, which blocks the AF-2 helix from adopting the active position. Biochemical analyses and structure-based mutagenesis indicate that this mode of co-repressor binding is highly conserved across nuclear receptors.
authors.affiliation: Nuclear Receptor Discovery Research, GlaxoSmithKline, Research Triangle Park, NC 27709, USA. ex11957@gsk.com
authors.forename: H Eric
authors.initials: HE
authors.lastname: Xu
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Stanley
authors.forename: Valerie G
authors.initials: VG
authors.lastname: Montana
authors.forename: Millard H
authors.initials: MH
authors.lastname: Lambert
authors.forename: Barry G
authors.initials: BG
authors.lastname: Shearer
authors.forename: Jeffery E
authors.initials: JE
authors.lastname: Cobb
authors.forename: David D
authors.initials: DD
authors.lastname: McKee
authors.forename: Cristin M
authors.initials: CM
authors.lastname: Galardi
authors.forename: Kelli D
authors.initials: KD
authors.lastname: Plunket
authors.forename: Robert T
authors.initials: RT
authors.lastname: Nolte
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Parks
authors.forename: John T
authors.initials: JT
authors.lastname: Moore
authors.forename: Steven A
authors.initials: SA
authors.lastname: Kliewer
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Willson
authors.forename: Julie B
authors.initials: JB
authors.lastname: Stimmel
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D020128:Inhibitory Concentration 50; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D056985:Nuclear Receptor Co-Repressor 2; D010080:Oxazoles / Q000378:metabolism / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000819:agonists / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry* / Q000378:metabolism*; D016415:Sequence Alignment; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000819:agonists / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D004268:DNA-Binding Proteins; C442829:GW 409544; C449302:GW 6471; D008024:Ligands; C539130:NCOR2 protein, human; D056985:Nuclear Receptor Co-Repressor 2; D010080:Oxazoles; D018160:Receptors, Cytoplasmic and Nuclear; D012097:Repressor Proteins; D014157:Transcription Factors; D014443:Tyrosine