T0070907, a Selective Ligand for Peroxisome Proliferator-activated Receptor γ, Functions as an Antagonist of Biochemical and Cellular Activities
The nuclear hormone receptor peroxisome proliferator-activated receptor γ (PPARγ (NR1C3)) plays a central role in adipogenesis and is the molecular target for the thiazolidinedione (TZD) class of antidiabetic drugs. In a search for novel non-TZD ligands for PPARγ, T0070907 was identified as a potent and selective PPARγ antagonist. With an apparent binding affinity (concentration at 50% inhibition of [3H]rosiglitazone binding or IC50) of 1 nm, T0070907 covalently modifies PPARγ on cysteine 313 in helix 3 of human PPARγ2. T0070907 blocked PPARγ function in both cell-based reporter gene and adipocyte differentiation assays. Consistent with its role as an antagonist of PPARγ, T0070907 blocked agonist-induced recruitment of coactivator-derived peptides to PPARγ in a homogeneous time-resolved fluorescence-based assay and promoted recruitment of the transcriptional corepressor NCoR to PPARγ in both glutathione S-transferase pull-down assays and a PPARγ/retinoid X receptor (RXR) α-dependent gel shift assay. Studies with mutant receptors suggest that T0070907 modulates the interaction of PPARγ with these cofactor proteins by affecting the conformation of helix 12 of the PPARγ ligand-binding domain. Interestingly, whereas the T0070907-induced NCoR recruitment to PPARγ/RXRα heterodimer can be almost completely reversed by the simultaneous treatment with RXRα agonist LGD1069, T0070907 treatment has only modest effects on LGD1069-induced coactivator recruitment to the PPARγ/RXRα heterodimer. These results suggest that the activity of PPARγ antagonists can be modulated by the availability and concentration of RXR agonists. T0070907 is a novel tool for the study of PPARγ/RXRα heterodimer function. The nuclear hormone receptor peroxisome proliferator-activated receptor γ (PPARγ (NR1C3)) plays a central role in adipogenesis and is the molecular target for the thiazolidinedione (TZD) class of antidiabetic drugs. In a search for novel non-TZD ligands for PPARγ, T0070907 was identified as a potent and selective PPARγ antagonist. With an apparent binding affinity (concentration at 50% inhibition of [3H]rosiglitazone binding or IC50) of 1 nm, T0070907 covalently modifies PPARγ on cysteine 313 in helix 3 of human PPARγ2. T0070907 blocked PPARγ function in both cell-based reporter gene and adipocyte differentiation assays. Consistent with its role as an antagonist of PPARγ, T0070907 blocked agonist-induced recruitment of coactivator-derived peptides to PPARγ in a homogeneous time-resolved fluorescence-based assay and promoted recruitment of the transcriptional corepressor NCoR to PPARγ in both glutathione S-transferase pull-down assays and a PPARγ/retinoid X receptor (RXR) α-dependent gel shift assay. Studies with mutant receptors suggest that T0070907 modulates the interaction of PPARγ with these cofactor proteins by affecting the conformation of helix 12 of the PPARγ ligand-binding domain. Interestingly, whereas the T0070907-induced NCoR recruitment to PPARγ/RXRα heterodimer can be almost completely reversed by the simultaneous treatment with RXRα agonist LGD1069, T0070907 treatment has only modest effects on LGD1069-induced coactivator recruitment to the PPARγ/RXRα heterodimer. These results suggest that the activity of PPARγ antagonists can be modulated by the availability and concentration of RXR agonists. T0070907 is a novel tool for the study of PPARγ/RXRα heterodimer function. Peroxisome proliferator-activated receptor γ (PPARγ 1The abbreviations used are: PPARγperoxisome proliferator-activated receptor γRXRretinoid X receptorTZDthiazolidinedioneNHRnuclear hormone receptorPPREPPAR-response elementHTRFhomogeneous time-resolved fluorescenceLBDligand-binding domainGSTglutathione S-transferaseMALDI-TOFmatrix-assisted laser desorption ionization time-of-flightMSmass spectroscopyGMSAgel mobility shift assayCHAPS3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate]Gal4-UASGal4 upstream activating sequencewtwild typehPPARγ1full-length human PPARγ1hhumanESIelectrospray ionizationSPAscintillation proximity assayWCEwhole-cell extract1The abbreviations used are: PPARγperoxisome proliferator-activated receptor γRXRretinoid X receptorTZDthiazolidinedioneNHRnuclear hormone receptorPPREPPAR-response elementHTRFhomogeneous time-resolved fluorescenceLBDligand-binding domainGSTglutathione S-transferaseMALDI-TOFmatrix-assisted laser desorption ionization time-of-flightMSmass spectroscopyGMSAgel mobility shift assayCHAPS3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate]Gal4-UASGal4 upstream activating sequencewtwild typehPPARγ1full-length human PPARγ1hhumanESIelectrospray ionizationSPAscintillation proximity assayWCEwhole-cell extract (NR1C3)) is a member of the nuclear hormone receptor (NHR) superfamily of ligand-activated transcription factors (1Rosen E.D. Spiegelman B.M. J. Biol. Chem. 2001; 276: 37731-37734Abstract Full Text Full Text PDF PubMed Scopus (1063) Google Scholar, 2Nuclear Receptors Nomenclature Committee, Cell 97, 1999, 161–163Google Scholar). At least two PPARγ isoforms exist, γ1 and γ2, resulting from transcription from two different promoters upstream of the PPAR gene (3Fajas L. Auboeuf D. Raspe E. Schoonjans K. Lefebvre A.M. Saladin R. Najib J. Laville M. Fruchart J.C. Deeb S. Vidal-Puig A. Flier J. Briggs M.R. Staels B. Vidal H. Auwerx J. J. Biol. Chem. 1997; 272: 18779-18789Abstract Full Text Full Text PDF PubMed Scopus (1072) Google Scholar, 4Fajas L. Fruchart J.C. Auwerx J. FEBS Lett. 1998; 438: 55-60Crossref PubMed Scopus (307) Google Scholar). PPARγ2 possesses 30 additional amino acids at its amino terminus. PPARγ1 is expressed broadly in many tissues, whereas PPARγ2 is expressed predominantly in adipose tissue. Both “gain of function” and “loss of function” studies strongly support a critical role for PPARγ in adipocyte gene expression and differentiation (5Lowell B.B. Cell. 1999; 99: 239-242Abstract Full Text Full Text PDF PubMed Scopus (337) Google Scholar). peroxisome proliferator-activated receptor γ retinoid X receptor thiazolidinedione nuclear hormone receptor PPAR-response element homogeneous time-resolved fluorescence ligand-binding domain glutathione S-transferase matrix-assisted laser desorption ionization time-of-flight mass spectroscopy gel mobility shift assay 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate] Gal4 upstream activating sequence wild type full-length human PPARγ1 human electrospray ionization scintillation proximity assay whole-cell extract peroxisome proliferator-activated receptor γ retinoid X receptor thiazolidinedione nuclear hormone receptor PPAR-response element homogeneous time-resolved fluorescence ligand-binding domain glutathione S-transferase matrix-assisted laser desorption ionization time-of-flight mass spectroscopy gel mobility shift assay 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate] Gal4 upstream activating sequence wild type full-length human PPARγ1 human electrospray ionization scintillation proximity assay whole-cell extract Like other members of the NHR superfamily, PPARγ binds to a DNA-response element (PPAR-response element or PPRE) upstream of the coding regions of target genes and forms a heterodimeric complex with one of the three retinoid X receptor (RXR) proteins (1Rosen E.D. Spiegelman B.M. J. Biol. Chem. 2001; 276: 37731-37734Abstract Full Text Full Text PDF PubMed Scopus (1063) Google Scholar). Binding of ligands to PPARγ causes conformational changes in the receptor, in particular to α-helix 12 (H12), which is located at the carboxyl-terminal end of the protein and forms part of the transcriptional activation function (AF-2). When agonists bind to PPARγ, H12 along with H3, H4, and H5 form a charge clamp and a hydrophobic pocket that allows the recruitment of coactivator protein complexes that are essential for transcriptional activation of PPARγ target genes (6Nolte R.T. Wisely G.B. Westin S. Cobb J.E. Lambert M.H. Kurokawa R. Rosenfeld M.G. Willson T.M. Glass C.K. Milburn M.V. Nature. 1998; 395: 137-143Crossref PubMed Scopus (1645) Google Scholar). Although PPARγ, in isolation, is capable of binding to transcriptional corepressor proteins NCoR and SMRT in the absence of ligand, PPARγ does not interact with these corepressors in the context of the RXR heterodimer nor does the PPARγ/RXR heterodimer repress transcription of PPARγ target genes, unlike heterodimers of RXR with thyroid hormone receptor or retinoic acid receptor (7Zamir I. Zhang J. Lazar M.A. Genes Dev. 1997; 11: 835-846Crossref PubMed Scopus (200) Google Scholar). Two explanations for the difference in PPARγ/corepressor interaction on and off DNA have been offered. The orientation of PPARγ and RXR on a PPRE could simply inhibit the binding of corepressor (8DiRenzo J. Soderstrom M. Kurokawa R. Ogliastro M.H. Ricote M. Ingrey S. Horlein A. Rosenfeld M.G. Glass C.K. Mol. Cell. Biol. 1997; 17: 2166-2176Crossref PubMed Scopus (250) Google Scholar). Alternatively, PPARγ may be unable to stabilize a conformation of RXR that is permissive for corepressor interaction; unlike TR and retinoic acid receptor, PPARγ is unable to interact with H12 from RXR (9Zhang J., Hu, X. Lazar M.A. Mol. Cell. Biol. 1999; 19: 6448-6457Crossref PubMed Scopus (91) Google Scholar). Because other NHR antagonists stabilize the interaction of corepressors with their cognate receptors, PPARγ antagonists or inverse agonists would be useful tools to study PPARγ/corepressor interaction. One way to test these hypotheses is to study the effects of a PPARγ antagonist or inverse agonist on corepressor binding. This avenue has not yet been explored. Both natural and synthetic ligands have been reported for PPARγ (reviewed in Ref. 10Willson T.M. Lambert M.H. Kliewer S.A. Annu. Rev. Biochem. 2001; 70: 341-367Crossref PubMed Scopus (536) Google Scholar). Naturally occurring compounds that have been reported to bind PPARγ include a number of fatty acids and eicosanoid derivatives such as 9- or 13-hydroxyoctadienoic acid and prostaglandin derivative 15-deoxy-Δ13,14-prostaglandin J2. The most widely used synthetic agonists of PPARγ are members of a class of antidiabetic agents known as thiazolidinediones (TZDs), including rosiglitazone, troglitazone, and pioglitazone. More recently, a series of tyrosine-based PPARγ agonists exemplified by GI262570 have been shown to be among the highest affinity PPARγ ligands described thus far. Synthetic partial agonists identified include GW0072 (11Oberfield J.L. Collins J.L. Holmes C.P. Goreham D.M. Cooper J.P. Cobb J.E. Lenhard J.M. Hull-Ryde E.A. Mohr C.P. Blanchard S.G. Parks D.J. Moore L.B. Lehmann J.M. Plunket K. Miller A.B. Milburn M.V. Kliewer S.A. Willson T.M. Proc. Natl. Acad. Sci. U. S. A. 1999; 96: 6102-6106Crossref PubMed Scopus (312) Google Scholar), L-764406 (12Elbrecht A. Chen Y. Adams A. Berger J. Griffin P. Klatt T. Zhang B. Menke J. Zhou G. Smith R.G. Moller D.E. J. Biol. Chem. 1999; 274: 7913-7922Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar), 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (13Wang Y. Porter W.W. Suh N. Honda T. Gribble G.W. Leesnitzer L.M. Plunket K.D. Mangelsdorf D.J. Blanchard S.G. Willson T.M. Sporn M.B. Mol. Endocrinol. 2000; 14: 1550-1556Crossref PubMed Google Scholar), and Fmoc (N-(9-fluorenyl)methoxycarbonyl)-l-leucine (14Rocchi S. Picard F. Vamecq J. Gelman L. Potier N. Zeyer D. Dubuquoy L. Bac P. Champy M.F. Plunket K.D. Leesnitzer L.M. Blanchard S.G. Desreumaux P. Moras D. Renaud J.P. Auwerx J. Mol. Cell. 2001; 8: 737-747Abstract Full Text Full Text PDF PubMed Scopus (263) Google Scholar). Several synthetic antagonists have also been described, these include bisphenol A diglycidyl ether (15Wright H.M. Clish C.B. Mikami T. Hauser S. Yanagi K. Hiramatsu R. Serhan C.N. Spiegelman B.M. J. Biol. Chem. 2000; 275: 1873-1877Abstract Full Text Full Text PDF PubMed Scopus (331) Google Scholar), GW9662 (10Willson T.M. Lambert M.H. Kliewer S.A. Annu. Rev. Biochem. 2001; 70: 341-367Crossref PubMed Scopus (536) Google Scholar), and PD068235 (16Camp H.S. Chaudhry A. Leff T. Endocrinology. 2001; 142: 3207-3213Crossref PubMed Scopus (77) Google Scholar). However, relatively little is known about how these compounds affect PPARγ/RXR heterodimer function. Here, we describe a novel, potent, and selective PPARγ ligand, T0070907. By using a variety of biochemical and cell-based assays, we demonstrate that T0070907 is a PPARγ antagonist. Our studies suggest that T0070907 modulates the interaction of PPARγ with cofactor proteins by affecting the conformation of helix 12 of the PPARγ ligand-binding domain (LBD). Finally, our studies reveal a functional asymmetry between the effects of PPARγ and RXR ligands on the activity of the permissive PPARγ/RXRα heterodimer. PPARγ and RXRα proteins by in and used in gel mobility shift assay expressed from and PPARγ, the full-length human acids of full-length human acids of The used to human NCoR protein from the expression was by DNA amino acids the and of the was by DNA amino acids the of at the is amino acid with for at in 1 was on an The gel PPARγ was with at for 12 and in using an of of binding of T0070907 to PPARγ was with a and an The was by acid in in and at a of of the was and on a with 3 of acid and with The was in with The mass was using and A. Chem. PubMed Scopus Google Scholar). The was and to by The with of a 50% acid and to with a additional of a acid was and a was a with for the with acid of 50% acid was used to the a the of the mass the mass was only on M. G. M. Chem. PubMed Scopus Google Scholar). assays as described G. Y. S. A. J.M. Smith R.G. Moller D.E. Mol. Endocrinol. 1998; PubMed Scopus Google with the as a 1 1 with and of in as in the and for 1 at with the and the was for an additional 1 at in and fluorescence was on an expressed as the of the at and by a of protein was with of in binding in binding for at with 1 of binding the protein was with of in protein and the concentration in a of at for with binding as the protein was with of at on a and by the binding affinity of T0070907 to the scintillation proximity assay was as described (12Elbrecht A. Chen Y. Adams A. Berger J. Griffin P. Klatt T. Zhang B. Menke J. Zhou G. Smith R.G. Moller D.E. J. Biol. Chem. 1999; 274: 7913-7922Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar, S.A. Wisely G.B. Kliewer S.A. Mangelsdorf D.J. Proc. Natl. Acad. Sci. U. S. A. 1999; 96: PubMed Scopus Google with the A 1 of of and of T0070907 in for 1 at of in and the was for 1 in was used for PPARγ, and A.M. L. Parks D.J. Blanchard S.G. Kliewer S.A. Lehmann J.M. Willson T.M. Chem. Biol. 1997; Full Text PDF PubMed Scopus Google was used for and Our to studies S.A. K. D.J. Nature. PubMed Scopus Google Scholar, Mol. Cell. Biol. 2000; PubMed Scopus Google with the The sequence of the DNA used in the was from the PPRE of the gene PPARγ and RXRα in 1 and with or NCoR for 30 at on a gel in and in by at to reporter assays of using to the and to as described A. J. Biol. Chem. Full Text PDF PubMed Google with the to in with and to with and 1 was with with 1 In a search for novel non-TZD ligands for PPARγ, T0070907 was identified to bind PPARγ with capable of [3H]rosiglitazone with an apparent of 1 as shown in T0070907 among PPAR with a for PPARγ and In with the and A.M. L. Parks D.J. Blanchard S.G. Kliewer S.A. Lehmann J.M. Willson T.M. Chem. Biol. 1997; Full Text PDF PubMed Scopus Google Scholar), T0070907 has an apparent of to and to The of T0070907 on the transcriptional activity of PPARγ in a cell-based reporter gene assay was with an expression that the PPARγ to the binding with a reporter gene the transcriptional of the Gal4 upstream activating sequence shown in transcription to whereas T0070907 has a on In T0070907 is a potent in the of PPARγ in the of This inhibition is not to as the concentration to 50% of is not The of T0070907 was also in cell-based reporter gene assays. with a reporter and expression the of the X receptor, the X receptor the X receptor or X receptor to the binding domain. shown in T0070907 at 1 has on the transcriptional activity of other receptor These results demonstrate that T0070907 is a antagonist. T0070907 could the of adipogenesis by of the shown in the treatment of and promoted in In in these was completely with both 1 T0070907 and the differentiation effects of T0070907 adipogenesis was by treatment with the PPARγ not the by which T0070907 PPARγ its binding was unable to T0070907 to PPARγ that the binding of T0070907 was not the of the interaction between T0070907 and PPARγ, and to the of we studies mass The binding of T0070907 of to PPARγ would in a mass of the by By the of PPARγ with and T0070907 a the T0070907 acids was identified on its mass shift to not The binding on was with mass The and of are shown at the of with the in the mass The mass difference between the and identified as the of by T0070907. In and also the of in T0070907 binding to PPARγ, a mutant PPARγ was in which to a and the protein was expressed and was with wild type PPARγ or the mutant as described, and the by shown in was only to the wild type protein of wild type and mutant PPARγ to is for the binding of T0070907 to The of the was in a whole-cell extract from protein was with the and and on an shown in the PPARγ was by the of many other proteins in the By using the homogeneous time-resolved fluorescence we an assay to study the effects of PPARγ ligands on the interaction of PPARγ with of coactivator or corepressor peptides of amino acids in from from coactivator and corepressor proteins D. Mol. Endocrinol. 2000; 14: PubMed Scopus Google Scholar, M.G. Glass C.K. J. Biol. Chem. 2001; 276: Full Text Full Text PDF PubMed Scopus Google Scholar). The effects of ligands on PPARγ binding to of peptides are shown in The that from have to between different functional of PPARγ known PPARγ agonists such as rosiglitazone, troglitazone, and the GI262570 T.M. J. Chem. 2000; PubMed Scopus Google and troglitazone, which both to the to other to tyrosine-based GI262570 additional peptides and that PPARγ a different conformation to with the conformation by the receptor to the In the novel PPARγ T0070907 a recruitment of peptides from corepressor proteins NCoR and and with the T0070907 to the between PPARγ and coactivator-derived of amino acid and of peptides used in the is in are on the with in a The is in are on the with In to these and with two peptides from a coactivator and a corepressor 1 and shown in and promoted the recruitment of from coactivator to PPARγ, the interaction between PPARγ and a from corepressor In T0070907 the interaction between PPARγ and the coactivator-derived in the absence of ligand, the recruitment of the to T0070907 also the effects of in a these by using an the effects of T0070907 on using a pull-down assay. shown in the interaction between the and NCoR in a with an with its binding affinity to the other T0070907 promoted a in NCoR binding to with the results in the assay. By shown that T0070907 strongly recruitment of NCoR to the PPARγ in both and pull-down assays, we used a to could also in the context of the PPARγ/RXRα heterodimer. shown in in PPARγ and RXRα can bind to a DNA from the of gene This shift in mobility is on the of both PPARγ and RXRα not the of a functional PPARγ/RXRα heterodimer these NCoR could not bind to the PPARγ/RXRα heterodimer in the absence of and and to Ref. J., Hu, X. Lazar M.A. Mol. Cell. Biol. 1999; 19: 6448-6457Crossref PubMed Scopus (91) Google Scholar), T0070907 was to a in the recruitment of NCoR to the heterodimeric complex 3 and that NCoR recruitment was the of T0070907 binding to PPARγ and to the of the PPARγ conformational changes with T0070907 we the effects of H12 from both receptors on the binding of NCoR to the heterodimer. The of PPARγ H12 (PPARγ the interaction of NCoR with the T0070907 not of binding In the PPARγ heterodimer to T0070907 and almost PPARγ heterodimer could be to form the complex in the of the antagonist H12 in both PPARγ and RXRα with NCoR in the absence of ligand, as in the of the PPARγ T0070907 almost on NCoR recruitment The effects between PPARγ and RXRα by the effects of simultaneous of RXRα agonist and PPARγ antagonist on the recruitment of coactivator and corepressor proteins to the heterodimer. Because the RXRα heterodimers strongly with NCoR the wild heterodimers we the effects of an RXRα M.F. Zhang L. D.E. Berger E. J. Chem. PubMed Scopus Google Scholar), on T0070907-induced NCoR recruitment to PPARγ and PPARγ the of NCoR binding to both of heterodimer complexes and was not to inhibit completely corepressor binding to the PPARγ complex as was in the PPARγ that the of on NCoR recruitment was not to T0070907 from binding to the PPARγ/RXRα which PPARγ was with T0070907 for an to the of other of the and to binding on difference on the recruitment of NCoR to the PPARγ/RXRα heterodimer was with or with T0070907 not The effects of T0070907 binding to PPARγ on the of RXRα to interact with also In the of the RXRα agonist LGD1069, the coactivator protein can be to the PPARγ/RXRα as by the complex in This complex was not in the of or in an RXR H12 mutant Mol. Cell. Biol. 2000; PubMed Scopus Google that was to the RXRα When to the with LGD1069, T0070907 to have a modest on of the complex by and have identified a affinity PPARγ that PPARγ activity in both biochemical and cell-based assays. T0070907 is selective for PPARγ other and proteins in an that T0070907 modifies PPARγ on in helix 3 of the a that is in three PPAR This that other in the binding pocket the binding of T0070907 to Interestingly, is also the of by a PPARγ partial agonist that was described (12Elbrecht A. Chen Y. Adams A. Berger J. Griffin P. Klatt T. Zhang B. Menke J. Zhou G. Smith R.G. Moller D.E. J. Biol. Chem. 1999; 274: 7913-7922Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar). T0070907 as a PPARγ antagonist in cell-based assays. blocked by the as as adipogenesis in with a differentiation these results support the role for PPARγ in The antagonist of T0070907 also in a variety of in biochemical assays using the PPARγ T0070907 agonist-induced between the PPARγ and coactivator-derived peptides and promoted recruitment of in assays The of T0070907 on of corepressor complex was also in the pull-down assay studies L.M. Kurokawa R. A. Lambert M.H. Milburn M.V. Glass C.K. Rosenfeld M.G. Genes Dev. 1999; PubMed Scopus Google Scholar, L. E. K. Genes Dev. 1999; PubMed Scopus Google Scholar, X. Lazar M.A. Nature. 1999; PubMed Scopus Google have that corepressors bind to a hydrophobic on NHR by H3, and This binding with that by NHR agonists the interaction between NHR and and is that the conformation of H12 by agonists the corepressor binding In the H12 of NHR is to in including the Consistent with H12 is for NCoR binding to most and of H12 from PPARγ or RXRα the recruitment of NCoR to the PPARγ/RXRα heterodimer (9Zhang J., Hu, X. Lazar M.A. Mol. Cell. Biol. 1999; 19: 6448-6457Crossref PubMed Scopus (91) Google M. J.M. M. Adams M. Lazar M.A. J. Biol. Chem. 2000; 275: Full Text Full Text PDF PubMed Scopus Google T0070907 can also NCoR recruitment to PPARγ/RXRα T0070907 can only recruitment of NCoR to complexes PPARγ not to complexes PPARγ These results suggest that the of T0070907 on the heterodimer is PPARγ and that T0070907 NCoR recruitment T0070907 treatment or the of H12 stabilize NCoR recruitment to that T0070907 most on PPARγ by H12 from the The of RXRα H12 domain has a with T0070907 treatment or PPARγ on the recruitment of NCoR to PPARγ/RXRα heterodimer Two are on NCoR protein L.M. Kurokawa R. A. Lambert M.H. Milburn M.V. Glass C.K. Rosenfeld M.G. Genes Dev. 1999; PubMed Scopus Google Scholar, L. E. K. Genes Dev. 1999; PubMed Scopus Google Scholar, X. Lazar M.A. Nature. 1999; PubMed Scopus Google Scholar), the of H12 from RXRα with T0070907 treatment or the of H12 from PPARγ allows the binding of both to PPARγ/RXRα heterodimer. In to the of the PPARγ and RXRα to NCoR recruitment to the the effects of simultaneous treatment with T0070907 and the in NCoR recruitment to the PPARγ and PPARγ heterodimers in a studies of the the and a PPARγ/RXRα heterodimer to suggest molecular for these The RXR heterodimer which is of from and of both receptors In a between the acid of from PPARγ H12 and from RXRα the of H12 from PPARγ in the conformation Lambert M.H. Miller A.B. Milburn M.V. Kliewer S.A. Willson T.M. Mol. Cell. 2000; Full Text Full Text PDF PubMed Scopus Google Scholar). In of the and reveal that ligand-binding conformational which the binding pocket in the of the binding pocket and by its binding of and to form an almost helix A. N. M. P. Moras D. J. 2000; 19: PubMed Google Scholar). Although the of a heterodimer has not yet been described, these results suggest that binding could to in the PPARγ/RXRα heterodimer that is located the of the conformational changes and RXR agonists could also the of the and the of PPARγ we suggest that binding binding of NCoR to the wild type heterodimer or by PPARγ and RXRα such that binding of NCoR is and by PPARγ H12 in the Consistent with the of on T0070907-induced recruitment of NCoR is potent on the PPARγ heterodimer on PPARγ heterodimer. In a of NCoR on PPARγ heterodimer at the highest and was also in NCoR binding to PPARγ heterodimer complexes not The of T0070907 on LGD1069-induced recruitment of coactivator was also the T0070907-induced NCoR recruitment to PPARγ/RXRα heterodimer can be almost completely reversed by the simultaneous treatment with RXRα agonist LGD1069, the effects of T0070907 on LGD1069-induced coactivator recruitment to the PPARγ/RXRα heterodimer are modest by These results suggest that RXRα agonists may have a on the conformation of the PPARγ/RXRα heterodimer PPARγ and PPARγ antagonist activity could be modulated by the availability and concentration of RXRα The in of these effects is the of our and and for support and of also and for and for