The Experts below are selected from a list of 1248 Experts worldwide ranked by ideXlab platform
Kristina Schoonjans - One of the best experts on this subject based on the ideXlab platform.
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Liver Receptor Homolog-1 is essential for pregnancy
2016Co-Authors: Cong Zhang, Kristina Schoonjans, Francesco J Demayo, Michael J. Large, Raj Duggavathi, John P, Ertug Kovanci, Bruce D. MurphyAbstract:Successful pregnancy requires coordination of an array of signals and factors from multiple tissues. One such element, the Liver Receptor Homolog-1 (Lrh-1, NR5A2), is an orphan nuclear Receptor that regulates metabolism and hormone synthesis1. It is strongly expressed in granulosa cells of ovarian follicles and in the corpus luteum of rodents2 and humans. Germline ablation of the Lrh-1 gene in mice is embryo-lethal at gastrulation3. Depletion of Lrh-1 in the ovarian follicle demonstrates that it regulates genes required for both steroid synthesis and ovulation4. To study the effects of Lrh-1 on mouse gestation, we disrupted its expression in the corpus luteum, resulting in luteal insufficiency. Hormone replacement permitted embryo implantation but was followed by gestational failure with impaired endometrial decidualization, compromised placental formation, fetal growth retardation, and fetal death. Lrh-1 is expressed in the mouse and human endometrium. In a human model of primary culture of endometrial stromal cells, depletion of Lrh-1 by siRNA abrogated decidualization. These findings demonstrate that Lrh-1 is necessary for maintenance of the corpus luteum, for promotion of decidualization and for placental formation. It therefore plays multiple, indispensible roles in establishing and sustaining pregnancy
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Hepatic glucose sensing and integrative pathways in the Liver
Cellular and Molecular Life Sciences, 2014Co-Authors: Maaike H Oosterveer, Kristina SchoonjansAbstract:The hepatic glucose-sensing system is a functional network of enzymes and transcription factors that is critical for the maintenance of energy homeostasis and systemic glycemia. Here we review the recent literature on its components and metabolic actions. Glucokinase (GCK) is generally considered as the initial postprandial glucose-sensing component, which acts as the gatekeeper for hepatic glucose metabolism and provides metabolites that activate the transcription factor carbohydrate response element binding protein (ChREBP). Recently, Liver Receptor homolog 1 (LRH-1) has emerged as an upstream regulator of the central GCK–ChREBP axis, with a critical role in the integration of hepatic intermediary metabolism in response to glucose. Evidence is also accumulating that O -linked β- N -acetylglucosaminylation ( O -GlcNAcylation) and acetylation can act as glucose-sensitive modifications that may contribute to hepatic glucose sensing by targeting regulatory proteins and the epigenome. Further elucidation of the components and functional roles of the hepatic glucose-sensing system may contribute to the future treatment of Liver diseases associated with deregulated glucose sensors.
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the orphan nuclear Receptor nr5a2 is essential for luteinization in the female mouse ovary
Endocrinology, 2014Co-Authors: Kalyne Bertolin, Kristina Schoonjans, Jan Gossen, Bruce D. MurphyAbstract:In the ovary, the follicular granulosa cells express the nuclear Receptor Nr5a2 (nuclear Receptor subfamily 5 group A member 2), also known as Liver Receptor Homolog-1, and after ovulation, Nr5a2 expression persists in the corpus luteum. Previous studies demonstrated that Nr5a2 is required for both ovulation and luteal steroid synthesis. Our objectives were to analyze the temporal sequence in the regulatory effects of Nr5a2 in the ovary, with focus on its contribution to luteal function. We developed a female mouse model of granulosa-specific targeted disruption from the formation of the antral follicles forward (genotype Nr5a2(Cyp19-/-)). Mice lacking Nr5a2 in granulosa cells of antral follicles are infertile. Although their cumulus cells undergo expansion after gonadotropin stimulation, ovulation is disrupted in those mice, at least in part, due to the down-regulation of the progesterone Receptor (Pgr) gene. The depletion of Nr5a2 in antral follicles permits formation of luteal-like structures but not functional corpora lutea, as evidenced by reduced progesterone levels and failure to support pseudopregnancy. Progesterone synthesis is affected by depletion of Nr5a2 due to, among others, defects in the transport of cholesterol, evidenced by down-regulation of Scarb1, Ldlr, and Star. Comparison of this mouse line with the models in which Nr5a2 is depleted from the primary follicle forward (genotype Nr5a2(Amhr2-/-)) and after the ovulatory signal (genotype Nr5a2(Pgr-/-)) demonstrates that Nr5a2 differentially regulates female fertility across the trajectory of follicular development.
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The small heterodimer partner is a gonadal gatekeeper of sexual maturation in male mice.
Genes and Development, 2007Co-Authors: David H Volle, Kristina Schoonjans, Benjamin C Magnier, Sander M Houten, Carolyn L Cummins, Raj Duggavathi, Jean-marc A. Lobaccaro, Guido Verhoeven, Johan AuwerxAbstract:The small heterodimer partner (SHP) is an atypical nuclear Receptor known mainly for its role in bile acid homeostasis in the enterohepatic tract. We explore here the role of SHP in the testis. SHP is expressed in the interstitial compartment of the adult testes, which contain the Leydig cells. SHP there inhibits the expression of steroidogenic genes, on the one hand by inhibiting the expression of the nuclear Receptors steroidogenic factor-1 and Liver Receptor Homolog-1 (lrh-1), and on the other hand by directly repressing the transcriptional activity of LRH-1. Consequently, in SHP knockout mice, testicular testosterone synthesis is increased independently of the hypothalamus-pituitary axis. Independent of its action on androgen synthesis, SHP also determines the timing of germ cell differentiation by controlling testicular retinoic acid metabolism. Through the inhibition of the transcriptional activity of retinoic acid Receptors, SHP controls the expression of stimulated by retinoic acid gene 8 (stra8) - a gene that is indispensable for germ cell meiosis and differentiation. Together, our data demonstrate new roles for SHP in testicular androgen and retinoic acid metabolism, making SHP a testicular gatekeeper of the timing of male sexual maturation.
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lrh 1 an orphan nuclear Receptor involved in development metabolism and steroidogenesis
Trends in Cell Biology, 2004Co-Authors: Elisabeth Fayard, Johan Auwerx, Kristina SchoonjansAbstract:Abstract The Liver Receptor Homolog-1 (LRH-1; NR5A2) and steroidogenic factor-1 (SF-1; NR5A1) are two orphan members of the Ftz-F1 subfamily of nuclear Receptors. LRH-1 is expressed in tissues derived from endoderm, including intestine, Liver and exocrine pancreas, as well as in the ovary. In these tissues, LRH-1 plays a predominant role in development, reverse cholesterol transport, bile-acid homeostasis and steroidogenesis. SF-1 expression is confined to steroidogenic tissues and the hypothalamo–pituitary–adrenal axis, where it is involved in the control of development, differentiation, steroidogenesis and sexual determination. In this article, we will review data concerning the structure, regulation and function of LRH-1. These data highlight structural similarities between LRH-1 and other Ftz-F1 members but also underscore important functional differences, assigning to LRH-1 a unique position among nuclear Receptors.
Bruce D. Murphy - One of the best experts on this subject based on the ideXlab platform.
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A role for orphan nuclear Receptor Liver Receptor Homolog-1 (LRH-1, NR5A2) in primordial follicle activation
Scientific Reports, 2021Co-Authors: Marie-charlotte Meinsohn, Camilla H. K. Hughes, Anthony Estienne, Hatice D. Saatcioglu, David Pépin, Raj Duggavathi, Bruce D. MurphyAbstract:Liver Receptor Homolog-1 (NR5A2) is expressed specifically in granulosa cells of developing ovarian follicles where it regulates the late stages of follicle development and ovulation. To establish its effects earlier in the trajectory of follicular development, NR5A2 was depleted from granulosa cells of murine primordial and primary follicles. Follicle populations were enumerated in neonates at postnatal day 4 (PND4) coinciding with the end of the formation of the primordial follicle pool. The frequency of primordial follicles in PND4 conditional knockout (cKO) ovaries was greater and primary follicles were substantially fewer relative to control (CON) counterparts. Ten-day in vitro culture of PND4 ovaries recapitulated in vivo findings and indicated that CON mice developed primary follicles in the ovarian medulla to a greater extent than did cKO animals. Two subsets of primordial follicles were observed in wildtype ovaries: one that expressed NR5A2 and the second in which the transcript was absent. Neither expressed the mitotic marker. KI-67, indicating their developmental quiescence. RNA sequencing on PND4 demonstrated that loss of NR5A2 induced changes in 432 transcripts, including quiescence markers, inhibitors of follicle activation, and regulators of cellular migration and epithelial-to-mesenchymal transition. These experiments suggest that NR5A2 expression poises primordial follicles for entry into the developing pool.
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the orphan nuclear Receptors steroidogenic factor 1 and Liver Receptor homolog 1 structure regulation and essential roles in mammalian reproduction
Physical Review, 2019Co-Authors: Marie-charlotte Meinsohn, Olivia Smith, Kalyne Bertolin, Bruce D. MurphyAbstract:Nuclear Receptors are intracellular proteins that act as transcription factors. Proteins with classic nuclear Receptor domain structure lacking identified signaling ligands are designated orphan nu...
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Liver Receptor Homolog-1 is essential for pregnancy
2016Co-Authors: Cong Zhang, Kristina Schoonjans, Francesco J Demayo, Michael J. Large, Raj Duggavathi, John P, Ertug Kovanci, Bruce D. MurphyAbstract:Successful pregnancy requires coordination of an array of signals and factors from multiple tissues. One such element, the Liver Receptor Homolog-1 (Lrh-1, NR5A2), is an orphan nuclear Receptor that regulates metabolism and hormone synthesis1. It is strongly expressed in granulosa cells of ovarian follicles and in the corpus luteum of rodents2 and humans. Germline ablation of the Lrh-1 gene in mice is embryo-lethal at gastrulation3. Depletion of Lrh-1 in the ovarian follicle demonstrates that it regulates genes required for both steroid synthesis and ovulation4. To study the effects of Lrh-1 on mouse gestation, we disrupted its expression in the corpus luteum, resulting in luteal insufficiency. Hormone replacement permitted embryo implantation but was followed by gestational failure with impaired endometrial decidualization, compromised placental formation, fetal growth retardation, and fetal death. Lrh-1 is expressed in the mouse and human endometrium. In a human model of primary culture of endometrial stromal cells, depletion of Lrh-1 by siRNA abrogated decidualization. These findings demonstrate that Lrh-1 is necessary for maintenance of the corpus luteum, for promotion of decidualization and for placental formation. It therefore plays multiple, indispensible roles in establishing and sustaining pregnancy
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the orphan nuclear Receptor nr5a2 is essential for luteinization in the female mouse ovary
Endocrinology, 2014Co-Authors: Kalyne Bertolin, Kristina Schoonjans, Jan Gossen, Bruce D. MurphyAbstract:In the ovary, the follicular granulosa cells express the nuclear Receptor Nr5a2 (nuclear Receptor subfamily 5 group A member 2), also known as Liver Receptor Homolog-1, and after ovulation, Nr5a2 expression persists in the corpus luteum. Previous studies demonstrated that Nr5a2 is required for both ovulation and luteal steroid synthesis. Our objectives were to analyze the temporal sequence in the regulatory effects of Nr5a2 in the ovary, with focus on its contribution to luteal function. We developed a female mouse model of granulosa-specific targeted disruption from the formation of the antral follicles forward (genotype Nr5a2(Cyp19-/-)). Mice lacking Nr5a2 in granulosa cells of antral follicles are infertile. Although their cumulus cells undergo expansion after gonadotropin stimulation, ovulation is disrupted in those mice, at least in part, due to the down-regulation of the progesterone Receptor (Pgr) gene. The depletion of Nr5a2 in antral follicles permits formation of luteal-like structures but not functional corpora lutea, as evidenced by reduced progesterone levels and failure to support pseudopregnancy. Progesterone synthesis is affected by depletion of Nr5a2 due to, among others, defects in the transport of cholesterol, evidenced by down-regulation of Scarb1, Ldlr, and Star. Comparison of this mouse line with the models in which Nr5a2 is depleted from the primary follicle forward (genotype Nr5a2(Amhr2-/-)) and after the ovulatory signal (genotype Nr5a2(Pgr-/-)) demonstrates that Nr5a2 differentially regulates female fertility across the trajectory of follicular development.
Robert J Fletterick - One of the best experts on this subject based on the ideXlab platform.
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Disulfide-Trapping Identifies a New, Effective Chemical Probe for Activating the Nuclear Receptor Human LRH-1 (NR5A2)
2016Co-Authors: Felipe De Jesus Cortez, Elena P Sablin, Holly A Ingraham, Robert J Fletterick, Miyuki Suzawa, Sam Irvy, John M. Bruning, Matthew P. Jacobson, Pamela M. EnglandAbstract:Conventional efforts relying on high-throughput physical and virtual screening of large compound libraries have failed to yield high-efficiency chemical probes for many of the 48 human nuclear Receptors. Here, we investigated whether disulfide-trapping, an approach new to nuclear Receptors, would provide effective lead compounds targeting human Liver Receptor homolog 1 (hLRH-1, NR5A2). Despite the fact that hLRH-1 contains a large ligand binding pocket and binds phospholipids with high affinity, existing synthetic hLRH-1 ligands are of limited utility due to poor solubility, low efficacy or significant off-target effects. Using disulfide-trapping, we identified a lead compound that conjugates with remarkably high-efficiency to a native cysteine residue (Cys346) lining the hydrophobic cavity in the ligand binding domain of hLRH-1. Guided by computational modeling and cellular assays, the lead compound was elaborated into ligands PME8 and PME9 that bind hLRH-1 reversibly (no cysteine reactivity) and increase hLRH-1 activity in cells. When compared with the existing hLRH-1 synthetic agonist RJW100, both PME8 and PME9 showed comparable induction of the LRH-1 dependent target gene CYP24A1 in human HepG2 cells, beginning as early as 3 h after drug treatment. The induction is specific as siRNA-mediated knock-down of hLRH-1 renders both PME8 and PME9 ineffective. These data show that PME8 and PME9 are potent activators of hLRH-1 and suggest that with further development this lead series may yield useful chemical probes for manipulating LRH-1 activity in vivo.
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structure of Liver Receptor homolog 1 nr5a2 with pip3 hormone bound in the ligand binding pocket
Journal of Structural Biology, 2015Co-Authors: Elena P Sablin, Raymond D Blind, Rubatharshini Uthayaruban, Hsiuju Chiu, Ashley M Deacon, Debanu Das, Holly A Ingraham, Robert J FletterickAbstract:The nuclear Receptor LRH-1 (Liver Receptor Homolog-1, NR5A2) is a transcription factor that regulates gene expression programs critical for many aspects of metabolism and reproduction. Although LRH-1 is able to bind phospholipids, it is still considered an orphan nuclear Receptor (NR) with an unknown regulatory hormone. Our prior cellular and structural studies demonstrated that the signaling phosphatidylinositols PI(4,5)P2 (PIP2) and PI(3,4,5)P3 (PIP3) bind and regulate SF-1 (Steroidogenic Factor-1, NR5A1), a close homolog of LRH-1. Here, we describe the crystal structure of human LRH-1 ligand binding domain (LBD) bound by PIP3 - the first phospholipid with a head group endogenous to mammals. We show that the phospholipid hormone binds LRH-1 with high affinity, stabilizing the Receptor LBD. While the hydrophobic PIP3 tails (C16/C16) are buried inside the LRH-1 ligand binding pocket, the negatively charged PIP3 head group is presented on the Receptor surface, similar to the phosphatidylinositol binding mode observed in the PIP3-SF-1 structure. Thus, data presented in this work reinforce our earlier findings demonstrating that signaling phosphatidylinositols regulate the NR5A Receptors LRH-1 and SF-1.
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structural basis of coactivation of Liver Receptor homolog 1 by β catenin
Proceedings of the National Academy of Sciences of the United States of America, 2012Co-Authors: Fumiaki Yumoto, Elena P Sablin, Phuong H Nguyen, John D Baxter, Paul Webb, Robert J FletterickAbstract:We report the three-dimensional structure of a β-catenin armadillo repeat in complex with the Liver Receptor Homolog-1 (LRH-1) ligand binding domain at 2.8 Å resolution as the first structure of β-catenin in complex with any nuclear Receptor. The surface of β-catenin that binds LRH-1 partly overlaps defined contact sites for peptide segments of β-catenin partners, including T-cell factor-4. The surface of LRH-1 that engages β-catenin is comprised of helices 1, 9, and 10 and is distinct from known interaction surfaces of LRH-1, including corepressor and coactivator binding sites. Targeted mutagenesis of amino acids forming both sides of the LRH-1/β-catenin interface reveals that they are essential for stable interactions between these proteins in solution. The LRH-1 binding site in β-catenin is also required for association with androgen Receptor, providing evidence that the observed LRH-1/β-catenin interaction may be prototypic.
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the structure of corepressor dax 1 bound to its target nuclear Receptor lrh 1
Proceedings of the National Academy of Sciences of the United States of America, 2008Co-Authors: Elena P Sablin, Holly A Ingraham, April Woods, Irina N Krylova, Peter H Hwang, Robert J FletterickAbstract:The Dax-1 protein is an enigmatic nuclear Receptor that lacks an expected DNA binding domain, yet functions as a potent corepressor of nuclear Receptors. Here we report the structure of Dax-1 bound to one of its targets, Liver Receptor homolog 1 (LRH-1). Unexpectedly, Dax-1 binds to LRH-1 using a new module, a repressor helix built from a family conserved sequence motif, PCFXXLP. Mutations in this repressor helix that are linked with human endocrine disorders dissociate the complex and attenuate Dax-1 function. The structure of the Dax-1:LRH-1 complex provides the molecular mechanism for the function of Dax-1 as a potent transcriptional repressor.
Suzanne G Mays - One of the best experts on this subject based on the ideXlab platform.
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development of a new class of Liver Receptor homolog 1 lrh 1 agonists by photoredox conjugate addition
Bioorganic & Medicinal Chemistry Letters, 2020Co-Authors: J L Cornelison, Suzanne G Mays, Eric A Ortlund, Michael L Cato, Alyssa M Johnson, Emma H Dagostino, Diana Melchers, Anamika Patel, Rene Houtman, Nathan T JuiAbstract:Abstract LRH-1 is a nuclear Receptor that regulates lipid metabolism and homeostasis, making it an attractive target for the treatment of diabetes and non-alcoholic fatty Liver disease. Building on recent structural information about ligand binding from our labs, we have designed a series of new LRH-1 agonists that further engage LRH-1 through added polar interactions. While the current synthetic approach to this scaffold has, in large part, allowed for decoration of the agonist core, significant variation of the bridgehead substituent is mechanistically precluded. We have developed a new synthetic approach to overcome this limitation, identified that bridgehead substitution is necessary for LRH-1 activation, and described an alternative class of bridgehead substituents for effective LRH-1 agonist development. We determined the crystal structure of LRH-1 bound to a bridgehead-modified compound, revealing a promising opportunity to target novel regions of the ligand binding pocket to alter LRH-1 target gene expression.
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development of the first low nanomolar Liver Receptor homolog 1 agonist through structure guided design
Journal of Medicinal Chemistry, 2019Co-Authors: Suzanne G Mays, Autumn R Flynn, J L Cornelison, C D Okafor, Hongxia Wang, Gueyshin Wang, X Huang, H N Donaldson, E J Millings, R PolavarapuAbstract:As a key regulator of metabolism and inflammation, the orphan nuclear hormone Receptor, Liver Receptor Homolog-1 (LRH-1), has potential as a therapeutic target for diabetes, nonalcoholic fatty Liver disease, and inflammatory bowel diseases (IBD). Discovery of LRH-1 modulators has been difficult, in part due to the tendency for synthetic compounds to bind unpredictably within the lipophilic binding pocket. Using a structure-guided approach, we exploited a newly discovered polar interaction to lock agonists in a consistent orientation. This enabled the discovery of the first low nanomolar LRH-1 agonist, one hundred times more potent than the best previous modulator. We elucidate a novel mechanism of action that relies upon specific polar interactions deep in the LRH-1 binding pocket. In an organoid model of IBD, the new agonist increases expression of LRH-1-controlled steroidogenic genes and promotes anti-inflammatory gene expression changes. These studies constitute major progress in developing LRH-1 modul...
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development of the first low nanomolar Liver Receptor homolog 1 agonist through structure guided design
bioRxiv, 2019Co-Authors: Suzanne G Mays, Autumn R Flynn, J L Cornelison, C D Okafor, Hongxia Wang, Gueyshin Wang, X Huang, H N Donaldson, E J Millings, R PolavarapuAbstract:As a key regulator of metabolism and inflammation, the orphan nuclear hormone Receptor, Liver Receptor Homolog-1 (LRH-1), has potential as a therapeutic target for diabetes, nonalcoholic fatty live disease, and inflammatory bowel diseases. Discovery of LRH-1 modulators has been difficult, in part due to the tendency for synthetic compounds to bind unpredictably within the lipophilic binding pocket. Using a structure-guided approach, we exploited a newly-discovered polar interaction to lock agonists in a consistent orientation. This enabled the discovery of the first low nanomolar LRH-1 agonist, one hundred times more potent than the best previous modulator. We elucidate a novel mechanism of action that relies upon specific polar interactions deep in the LRH-1 binding pocket. In an organoid model of inflammatory bowel disease, the new agonist increases expression ofLRH-1-conrolled steroidogenic genes and promotes anti-inflammatory gene expression changes. These studies constitute major progress in developing LRH-1 modulators with potential clinical utility.
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structure and dynamics of the Liver Receptor homolog 1 pgc1α complex
Molecular Pharmacology, 2017Co-Authors: Suzanne G Mays, Richard J Whitby, Denise C Okafor, Micheal L Tuntland, Venkatasubramanian Dharmarajan, Jozef Stec, Patrick R Griffin, Eric A OrtlundAbstract:Peroxisome proliferator-activated gamma coactivator 1-α (PGC1α) regulates energy metabolism by directly interacting with transcription factors to modulate gene expression. Among the PGC1α binding partners is Liver Receptor homolog 1 (LRH-1; NR5A2), an orphan nuclear hormone Receptor that controls lipid and glucose homeostasis. Although PGC1α is known to bind and activate LRH-1, mechanisms through which PGC1α changes LRH-1 conformation to drive transcription are unknown. Here, we used biochemical and structural methods to interrogate the LRH-1-PGC1α complex. Purified, full-length LRH-1, as well as isolated ligand binding domain, bound to PGC1α with higher affinity than to the coactivator, nuclear Receptor coactivator-2 (Tif2), in coregulator peptide recruitment assays. We present the first crystal structure of the LRH-1-PGC1α complex, which depicts several hydrophobic contacts and a strong charge clamp at the interface between these partners. In molecular dynamics simulations, PGC1α induced correlated atomic motion throughout the entire LRH-1 activation function surface, which was dependent on charge-clamp formation. In contrast, Tif2 induced weaker signaling at the activation function surface than PGC1α but promoted allosteric signaling from the helix 6/β-sheet region of LRH-1 to the activation function surface. These studies are the first to probe mechanisms underlying the LRH-1-PGC1α interaction and may illuminate strategies for selective therapeutic targeting of PGC1α-dependent LRH-1 signaling pathways.
Eric A Ortlund - One of the best experts on this subject based on the ideXlab platform.
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development of a new class of Liver Receptor homolog 1 lrh 1 agonists by photoredox conjugate addition
Bioorganic & Medicinal Chemistry Letters, 2020Co-Authors: J L Cornelison, Suzanne G Mays, Eric A Ortlund, Michael L Cato, Alyssa M Johnson, Emma H Dagostino, Diana Melchers, Anamika Patel, Rene Houtman, Nathan T JuiAbstract:Abstract LRH-1 is a nuclear Receptor that regulates lipid metabolism and homeostasis, making it an attractive target for the treatment of diabetes and non-alcoholic fatty Liver disease. Building on recent structural information about ligand binding from our labs, we have designed a series of new LRH-1 agonists that further engage LRH-1 through added polar interactions. While the current synthetic approach to this scaffold has, in large part, allowed for decoration of the agonist core, significant variation of the bridgehead substituent is mechanistically precluded. We have developed a new synthetic approach to overcome this limitation, identified that bridgehead substitution is necessary for LRH-1 activation, and described an alternative class of bridgehead substituents for effective LRH-1 agonist development. We determined the crystal structure of LRH-1 bound to a bridgehead-modified compound, revealing a promising opportunity to target novel regions of the ligand binding pocket to alter LRH-1 target gene expression.
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structure and dynamics of the Liver Receptor homolog 1 pgc1α complex
Molecular Pharmacology, 2017Co-Authors: Suzanne G Mays, Richard J Whitby, Denise C Okafor, Micheal L Tuntland, Venkatasubramanian Dharmarajan, Jozef Stec, Patrick R Griffin, Eric A OrtlundAbstract:Peroxisome proliferator-activated gamma coactivator 1-α (PGC1α) regulates energy metabolism by directly interacting with transcription factors to modulate gene expression. Among the PGC1α binding partners is Liver Receptor homolog 1 (LRH-1; NR5A2), an orphan nuclear hormone Receptor that controls lipid and glucose homeostasis. Although PGC1α is known to bind and activate LRH-1, mechanisms through which PGC1α changes LRH-1 conformation to drive transcription are unknown. Here, we used biochemical and structural methods to interrogate the LRH-1-PGC1α complex. Purified, full-length LRH-1, as well as isolated ligand binding domain, bound to PGC1α with higher affinity than to the coactivator, nuclear Receptor coactivator-2 (Tif2), in coregulator peptide recruitment assays. We present the first crystal structure of the LRH-1-PGC1α complex, which depicts several hydrophobic contacts and a strong charge clamp at the interface between these partners. In molecular dynamics simulations, PGC1α induced correlated atomic motion throughout the entire LRH-1 activation function surface, which was dependent on charge-clamp formation. In contrast, Tif2 induced weaker signaling at the activation function surface than PGC1α but promoted allosteric signaling from the helix 6/β-sheet region of LRH-1 to the activation function surface. These studies are the first to probe mechanisms underlying the LRH-1-PGC1α interaction and may illuminate strategies for selective therapeutic targeting of PGC1α-dependent LRH-1 signaling pathways.
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modulation of human nuclear Receptor lrh 1 activity by phospholipids and shp
Nature Structural & Molecular Biology, 2005Co-Authors: Eric A Ortlund, Isaac H Solomon, Janet M Hager, Rachid Safi, Yunhee Choi, Ziqiang Guan, Ashutosh Tripathy, Christian R H Raetz, Donald P Mcdonnell, David D MooreAbstract:The human nuclear Receptor Liver Receptor homolog 1 (hLRH-1) plays an important role in the development of breast carcinomas. This orphan Receptor is efficiently downregulated by the unusual co-repressor SHP and has been thought to be ligand-independent. We present the crystal structure at a resolution of 1.9 A of the ligand-binding domain of hLRH-1 in complex with the NR box 1 motif of human SHP, which we find contacts the AF-2 region of hLRH-1 using selective structural motifs. Electron density indicates phospholipid bound within the ligand-binding pocket, which we confirm using mass spectrometry of solvent-extracted samples. We further show that pocket mutations reduce phospholipid binding and Receptor activity in vivo. Our results indicate that hLRH-1's control of gene expression is mediated by phospholipid binding, and establish hLRH-1 as a novel target for compounds designed to slow breast cancer development.
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modulation of human nuclear Receptor lrh 1 activity by phospholipids and shp
Nature Structural & Molecular Biology, 2005Co-Authors: Eric A Ortlund, Yoon-kwang Lee, Isaac H Solomon, Janet M Hager, Rachid Safi, Yunhee Choi, Ziqiang Guan, Ashutosh Tripathy, Christian R H Raetz, Donald P McdonnellAbstract:The human nuclear Receptor Liver Receptor homolog 1 (hLRH-1) plays an important role in the development of breast carcinomas. This orphan Receptor is efficiently downregulated by the unusual co-repressor SHP and has been thought to be ligand-independent. We present the crystal structure at a resolution of 1.9 A of the ligand-binding domain of hLRH-1 in complex with the NR box 1 motif of human SHP, which we find contacts the AF-2 region of hLRH-1 using selective structural motifs. Electron density indicates phospholipid bound within the ligand-binding pocket, which we confirm using mass spectrometry of solvent-extracted samples. We further show that pocket mutations reduce phospholipid binding and Receptor activity in vivo. Our results indicate that hLRH-1's control of gene expression is mediated by phospholipid binding, and establish hLRH-1 as a novel target for compounds designed to slow breast cancer development.