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ABSTRACT: A rapid and eco-friendly synthesis of a sulfonamide library under flow conditions is described. The study illustrates an efficient, safe and easily scalable preparation of sulfonamides by use of a mesoreactor apparatus, thus demonstrating the impact of flow technologies within drug discovery. Waste minimization, employment of green media and non toxic reactants are achieved by the optimization of the flow set up and experimental protocol designed to sequentially synthesize primary, secondary and tertiary sulfonamides. Isolation of the products involves only extraction and precipitation affording pure compounds in good to high yields without further purification for biological evaluation.
ACS combinatorial science. 03/2013;
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Orlaith B Kelly,
Magdalena S Mroz,
Joseph B Ward,
Carolina Colliva,
Michael Scharl, Roberto Pellicciari,
John F Gilmer,
Padraic G Fallon,
Alan F Hofmann,
Aldo Roda,
Frank E Murray,
Stephen J Keely
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ABSTRACT: Dihydroxy bile acids, such as chenodeoxycholic acid (CDCA), are well-known to promote colonic fluid and electrolyte secretion, thereby causing diarrhoea associated with bile acid malabsorption. However, CDCA is rapidly metabolised by colonic bacteria to ursodeoxycholic acid (UDCA), the effects of which on epithelial transport are poorly characterised. Here, we investigated the role of UDCA in regulation of colonic epithelial secretion. Cl- secretion was measured across voltage-clamped monolayers of T84 cells and muscle-stripped sections of mouse or human colon. Cell surface biotinylation was used to assess abundance/surface expression of transport proteins. Acute (15 min) treatment of T84 cells with bilateral UDCA attenuated Cl- secretory responses to the Ca2+ and cAMP-dependent secretagogues, carbachol (CCh) and forskolin (FSK) to 14.0 ± 3.8% and 40.2 ± 7.4% of controls, respectively (n = 18; p < 0.001). An investigation of molecular targets involved revealed that UDCA acts by inhibiting Na+/K+-ATPase activity and basolateral K+ channel currents, without altering their cell surface expression. In contrast, intraperitoneal administration of UDCA (25 mg/kg) to mice enhanced agonist-induced colonic secretory responses, an effect we hypothesised to be due to bacterial metabolism of UDCA to lithocholic acid (LCA). Accordingly, LCA (50200 M) enhanced agonist-induced secretory responses in vitro and a metabolically stable UDCA analogue, 6-methyl-UDCA (6-MUDCA), exerted antisecretory actions in vitro and in vivo. In conclusion, UDCA exerts direct antisecretory actions on colonic epithelial cells and metabolically stable derivatives of the bile acid may offer a new approach for treating intestinal diseases associated with diarrhoea.
The Journal of Physiology 03/2013; · 4.72 Impact Factor
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ABSTRACT: Introduction: The G protein-coupled receptor TGR5 is a key player of the bile acid signaling network, and its activation has been proved to increase the glycemic control, to enhance energy expenditure and to exert anti-inflammatory actions. Accordingly, TGR5 ligands have emerged in drug discovery and preclinical appraisals as promising agents for the treatment of liver diseases, metabolic syndrome and related disorders. Areas covered: Recent advances in the field of TGR5 modulators are reviewed, with a particular attention on patent applications and peer-reviewed publications in the past 6 years. Expert opinion: Activation of TGR5 showed to protect mice from diabesity and insulin resistance, to improve liver functions, as well as to attenuate the development of atherosclerosis. However, although the efficacy of TGR5 agonists in mice is encouraging, further studies are needed to determine their potential in humans and to evaluate carefully the balance between the therapeutic benefits and adverse effects associated with the target. The development of new TGR5 selective ligands to support studies in animal models will surely facilitate the understanding of the complexity of TGR5 signaling network.
Expert Opinion on Therapeutic Patents 10/2012; · 3.57 Impact Factor
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Maura Marinozzi,
Andrea Carotti,
Emanuele Sansone,
Antonio Macchiarulo,
Emiliano Rosatelli,
Roccaldo Sardella,
Benedetto Natalini,
Giovanni Rizzo,
Luciano Adorini,
Daniela Passeri,
Francesca De Franco,
Mark Pruzanski, Roberto Pellicciari
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ABSTRACT: A virtual screening procedure was applied to the discovery of structurally diverse non-steroidal Farnesoid X Receptor (FXR) agonists. From 117 compounds selected by virtual screening, a total of 47 compounds were found to be FXR agonists, with 34 of them showing activity below a concentration of 20 μM. 1H-Pyrazole[3,4-e][1,4]thiazepin-7-one-based hit compound 7 was chosen for hit-to-lead optimization. A large number of 1H-pyrazole[3,4-e][1,4]thiazepin-7-one derivatives was designed, synthesized, and evaluated by a cell-based luciferase transactivation assay for their agonistic activity against FXR. Most of them exhibited low micromolar range of potency and very high efficacy.
Bioorganic & medicinal chemistry 04/2012; 20(11):3429-45. · 2.82 Impact Factor
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ABSTRACT: A multi-gram scale protocol for the N-acyl amidation of bile acids with glycine and taurine has been successfully developed under continuous flow processing conditions. Selecting ursodeoxycholic acid (UDCA) as the model compound and N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) as the condensing agent, a modular mesoreactor assisted flow set-up was employed to significantly speed up the optimization of the reaction conditions and the flow scale-up synthesis. The results in terms of yield, in line purification, analysis, and implemented flow set-up for the reaction optimization and large scale production are reported and discussed.
Organic & Biomolecular Chemistry 04/2012; 10(20):4109-15. · 3.70 Impact Factor
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Roberto Pellicciari,
Antimo Gioiello,
Paola Sabbatini,
Francesco Venturoni,
Roberto Nuti,
Carolina Colliva,
Giovanni Rizzo,
Luciano Adorini,
Mark Pruzanski,
Aldo Roda,
and Antonio Macchiarulo
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ABSTRACT: Grounding on our former 3D QSAR studies, a knowledge-based screen of natural bile acids from diverse animal species has led to the identification of avicholic acid as a selective but weak TGR5 agonist. Chemical modifications of this compound resulted in the disclosure of 6α-ethyl-16-epi-avicholic acid that shows enhanced potency at TGR5 and FXR receptors. The synthesis, biological appraisals, and structure–activity relationships of this series of compounds are herein described. Moreover, a thorough physicochemical characterization of 6α-ethyl-16-epi-avicholic acid as compared to naturally occurring bile acids is reported and discussed.
ACS Medicinal Chemistry Letters 02/2012; 3:273. · 3.36 Impact Factor
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Thijs W H Pols,
Mitsunori Nomura,
Taoufiq Harach,
Giuseppe Lo Sasso,
Maaike H Oosterveer,
Charles Thomas,
Giovanni Rizzo,
Antimo Gioiello,
Luciano Adorini, Roberto Pellicciari,
Johan Auwerx,
Kristina Schoonjans
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ABSTRACT: The G protein-coupled receptor TGR5 has been identified as an important component of the bile acid signaling network, and its activation has been linked to enhanced energy expenditure and improved glycemic control. Here, we demonstrate that activation of TGR5 in macrophages by 6α-ethyl-23(S)-methylcholic acid (6-EMCA, INT-777), a semisynthetic BA, inhibits proinflammatory cytokine production, an effect mediated by TGR5-induced cAMP signaling and subsequent NF-κB inhibition. TGR5 activation attenuated atherosclerosis in Ldlr(-/-)Tgr5(+/+) mice but not in Ldlr(-/-)Tgr5(-/-) double-knockout mice. The inhibition of lesion formation was associated with decreased intraplaque inflammation and less plaque macrophage content. Furthermore, Ldlr(-/-) animals transplanted with Tgr5(-/-) bone marrow did not show an inhibition of atherosclerosis by INT-777, further establishing an important role of leukocytes in INT-777-mediated inhibition of vascular lesion formation. Taken together, these data attribute a significant immune modulating function to TGR5 activation in the prevention of atherosclerosis, an important facet of the metabolic syndrome.
Cell metabolism 12/2011; 14(6):747-57. · 17.35 Impact Factor
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ABSTRACT: A new stereoselective synthesis of E-guggulsterone is described starting from androsten-3,17-dione. Protection of the ring A enonic system, followed by regioselective Wittig reaction and C-16 oxidation, affords E-guggulsterone in good yields and high stereoselectivity, making this approach easily accessible and scalable. Moreover, an original normal-phase HPLC method enabling the fast quantitation of the guggulsterone isomeric purity, combined with the suitability for sampling procedures, is detailed. The relying upon the cellulose-based Chiralpak IB column and the chloroform as the "non-standard" component of the eluent mixture, allows to get profitably high chromatographic performances.
Steroids 12/2011; 77(3):250-4. · 2.83 Impact Factor
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ABSTRACT: Ethyl diazo(3-hydroxy-2-oxo-2,3-dihydro-1H-indol-3-yl)acetate was prepared by aldol-type condensation of ethyl diazoacetate with isatin. A systematic and mechanistic study on the Lewis acid induced decomposition reaction of this valuable diazo precursor was carried out with the aim to gain new insights into the mechanistic aspects of the reaction as well as to further understand the factors and experimental conditions which affect the relative product distribution. The reaction, which may proceed via cationic and noncationic mechanisms, was found to be significantly influenced by the reaction environment determined by the characteristics of the Lewis acid employed, by the ability of the Lewis acid to form a complex with the alcohol functionality of the α-diazo-β-hydroxy ester, and by the polarity and nucleophilicity of the solvent used.
The Journal of Organic Chemistry 08/2011; 76(18):7431-7. · 4.45 Impact Factor
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ABSTRACT: Kynurenic acid (KYNA), an astrocyte-derived metabolite, antagonizes the α7 nicotinic acetylcholine receptor (α7nAChR) and, possibly, the glycine co-agonist site of the NMDA receptor at endogenous brain concentrations. As both receptors are involved in cognitive processes, KYNA elevations may aggravate, whereas reductions may improve, cognitive functions. We tested this hypothesis in rats by examining the effects of acute up- or downregulation of endogenous KYNA on extracellular glutamate in the hippocampus and on performance in the Morris water maze (MWM). Applied directly by reverse dialysis, KYNA (30-300 nM) reduced, whereas the specific kynurenine aminotransferase-II inhibitor (S)-4-(ethylsulfonyl)benzoylalanine (ESBA; 0.3-3 mM) raised, extracellular glutamate levels in the hippocampus. Co-application of KYNA (100 nM) with ESBA (1 mM) prevented the ESBA-induced glutamate increase. Comparable effects on hippocampal glutamate levels were seen after intra-cerebroventricular (i.c.v.) application of the KYNA precursor kynurenine (1 mM, 10 μl) or ESBA (10 mM, 10 μl), respectively. In separate animals, i.c.v. treatment with kynurenine impaired, whereas i.c.v. ESBA improved, performance in the MWM. I.c.v. co-application of KYNA (10 μM) eliminated the pro-cognitive effects of ESBA. Collectively, these studies show that KYNA serves as an endogenous modulator of extracellular glutamate in the hippocampus and regulates hippocampus-related cognitive function. Our results suggest that pharmacological interventions leading to acute reductions in hippocampal KYNA constitute an effective strategy for cognitive improvement. This approach might be especially useful in the treatment of cognitive deficits in neurological and psychiatric diseases that are associated with increased brain KYNA levels.
Neuropsychopharmacology: official publication of the American College of Neuropsychopharmacology 07/2011; 36(11):2357-67. · 6.99 Impact Factor
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ABSTRACT: In a line of research focused on the design, synthesis and development of new bile acid-based compounds, the physico-chemical profile of the molecules must be thoroughly explored and analyzed. In this scenario, a fast and reliable information on the critical micellar concentration (CMC) of specific compounds through a profitable chromatographic parameter can be of aid to rationally direct the synthesis of new molecular entities, mainly during the early stages of the drug-discovery process. The derived 'chromatographic hydrophobicity index' (CHI), usually employed for a fast access to the log P/log D value of physico-chemically diverse compounds and obtained via RP-gradient elution, was for the first time engaged in the bile acid field. Accordingly, 14 unconjugated bile acids harboured with a different number, position and orientation of hydroxy groups, as well as other substituents onto the steroidal backbone and side chain, were selected to build up a calibration curve. Such a collection of compounds was rationally assembled in order to manage an almost continuous range of CMC values (spanning the spectrophotometrically obtained CMCs between 5 and 25 mM). A high degree of correlation between CMC and CHI values was obtained (R(2) and cross-validated R(xv)(2) of the pCMC vs CHI plot equal to 0.975 and 0.966, respectively). A selected new subset of five confidential research bile acids with experimental CMCs in the range 6-19 mM was finally recruited to validate the proposed method. The high statistical quality of the established mathematical model turned out into a very appreciable predictive power.
Analytical and Bioanalytical Chemistry 05/2011; 401(1):267-74. · 3.78 Impact Factor
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ABSTRACT: Within our efforts in the discovery of novel potent and selective ligands for the FXR receptor, 23-N-(carbocinnamyloxy)-3α,7α-dihydroxy-6α-ethyl-24-nor-5β-cholan-23-amine was synthesized and evaluated for its ability to activate and modulate the biological response of the receptor. Alphascreen and RT-PCR revealed that the 6α-ethyl-24-norcholanyl-23-amine derivate behaves as full FXR agonist endowed with high binding affinity and efficacy, representing a promising lead candidate for further optimization. In addition, docking studies provide new insights into the molecular basis governing the partial and full agonist activity at FXR.
Bioorganic & medicinal chemistry 04/2011; 19(8):2650-8. · 2.82 Impact Factor
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ABSTRACT: Most researchers have sought to restore the activity of p53 by identifying small molecules able to block the interaction of p53 with mouse double minute 2 (MDM2). To the same end, some scientists are pursuing the development of compounds that can inhibit the ubiquitin-ligase (E3) activity of MDM2. In this article, we provide a perspective review on what is known about MDM2 E3 inhibitors and what major questions remain to be addressed to boost this line of research. Recent studies provide the proof of concept that the inhibition of MDM2 E3 activity represents a viable strategy for rescuing p53 activity from MDM2 inhibitory functions. It is likely that settling some open issues such as the site of action of these compounds and their specificity towards E3 ligase enzymes will open in the near feature new horizons in cancer therapy.
Expert Opinion on Therapeutic Patents 03/2011; 21(3):287-94. · 3.57 Impact Factor
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ABSTRACT: Alterations of p53 signalling pathway is the most frequent event in human cancers. About 50% of these, albeit showing wild-type p53, have flaws in the control mechanisms of p53 levels and activity. MDM2 and MDMX (MDM4) are the main negative regulators of p53. The relevance of MDM2 on the regulation of p53 levels and activity has fostered the development of strategies aimed at restoring p53 functions by blocking the physical interaction between MDM2 and p53. As a consequence, a number of different small molecules and peptidomimetics have been disclosed in the last decade as inhibitors of MDM2/p53 interaction. Recent studies, however, have thrust MDMX into the limelight as an additional chemotherapeutic target, suggesting the presence of a more complex relationship between MDM2, MDMX and p53. In this review article, we report key aspects of MDMX-mediated regulation of p53, recent advances in the structural characterization of the protein, and the progress made so far in the medicinal chemistry of MDMX ligands.
MedChemComm - Rapid communication of research in medicinal chemistry. 02/2011; 2(2040-25031):455-465.
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Roberto Pellicciari,
Emidio Camaioni,
Adam M. Gilbert,
Antonio Macchiarulo,
Jack A. Bikker,
Falgun Shah,
Joel Bard,
Gabriele Costantino,
Antimo Gioiello,
Graeme M. Robertson, [......],
Francesco Venturoni,
Paride Liscio,
Andrea Carotti,
Daniele Bellocchi,
Andrea Cozzi,
Andrew Wood,
Cathleen Gonzales,
Margaret M. Zaleska,
John W. Ellingboe,
Flavio Moroni
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ABSTRACT: Activation of poly(ADP-ribose) polymerase (PARP) is an important factor in controlling cell survival or death. As a consequence, therapeutic interventions with PARP-1 inhibitors are sought in different pathological conditions such as cancer, cardiovascular and inflammatory diseases, as well as brain ischemia. In the first part of this work, as a continuation of our efforts in the field, we report the design, synthesis and biological appraisal of novel potent PARP-1 inhibitors. A crystallization experiment is carried out to ascertain the mode of binding to PARP-1 of the most potent compound, namely 2-((dimethylamino)methyl)-9-hydroxythieno[2,3-c]isoquinolin-5(4H)-one (HYDAMTIQ), whilst molecular modeling studies are performed to infer the role of water molecules in ligand binding. In the second part of the work, we discuss the results of HYDAMTIQ in models of brain ischemia as well as its preliminary physicochemical and pharmacokinetic characterization. Collectively, the data obtained qualify HYDAMTIQ a
MedChemComm. 01/2011; 2:559-565.
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ABSTRACT: Owing to the exceptional sophistication of chiral ligand-exchange chromatography (CLEC) systems operating in the presence of chiral mobile phase (CMP) additives, only few studies dealing with mechanistic investigations have been presented so far. Nevertheless, dedicated computational protocols applied to simplified models, can furnish valuable information on the factors that mainly affect the overall enantiorecognition event. Accordingly, the extraordinary accordance observed between quantum mechanical (QM) calculations and crystallographic data led us to use optimized ternary complexes carrying the chiral selector O-benzyl-(S)-serine [(S)-OBS], as starting structures to build up a computational model enabling to explain the enantiomer elution order of amino acids with this enantioresolving agent. As a result of the calculation of 113 three-dimensional descriptors on the mixed complexes, and the generation of a decision tree, the delta-Energy of solvation (delta-E(sol)) was found to correctly classify all the compounds of the training set (20 species) according to the relative chromatographic behaviour. Thus, as a rule of thumb, the diastereomeric couples having a delta-E(sol) value lower than 5.321 kcal/mol (splitting node) experienced a "canonical" enantiomer elution order while an opposite situation occurred for all the others (reversed elution profile). The profitable predictive power of the developed model was assessed on the selected test set (5 species).
Journal of chromatography. A 10/2010; 1217(48):7523-7. · 4.19 Impact Factor
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ABSTRACT: The Small Heterodimer Partner (SHP) is an orphan nuclear receptor and an atypical member of the nuclear receptor superfamily Since its discovery, a growing body of evidences have pointed out a pivotal role for SHP in the transcriptional regulation of a variety of target genes involved in diverse metabolic pathways. While we have previously developed a homology model of the structure of SHP that was instrumental to identify a putative ligand binding pocket and suggest the possibility of the development of synthetic modulators, others reported that some atypical retinoids may represent the first synthetic ligands for this receptor. In this work, we report a combined computational approach aimed at shedding further lights on the binding mode and mechanism of action of some atypical retinoids as ligands of SHP. The results have been instrumental to design mutagenesis experiments whose preliminary data suggest the presence of a functional site in SHP as defined by residues Phe96, Arg138 and Arg238. While further experimental studies are ongoing, these findings constitute the basis for the design and identification of novel synthetic modulators of SHP functions.
Journal of Computer-Aided Molecular Design 09/2010; 24(11):943-56. · 3.39 Impact Factor
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ABSTRACT: The design and optimization of small molecule inhibitors of the murine double minute clone 2-p53 (p53-MDM2) interaction has attracted a great deal of interest as a way to novel anticancer therapies. Herein we report 3D-QSAR studies of 41 small molecule inhibitors based on the use of molecular interaction fields and docking experiments as part of an approach to generating predictive models of MDM2 affinity and shedding further light on the structural elements of the ligand-target interaction. These studies have yielded predictive models explaining much of the variance of the 41 compound training set and satisfactorily predicting with 75% success an external test set of 36 compounds. Not surprisingly, and in full agreement with previous data, inspection of the 3D-QSAR coefficients reveals that the major driving force for potent inhibition is given by the hydrophobic interaction between the inhibitors and the p53 binding cleft of MDM2. More surprisingly, and challenging previous suggestions, the projection of the 3D-QSAR coefficients back onto the experimental structures of MDM2 provides an intriguing hypothesis concerning an active role played by the N-terminal region of MDM2 in ligand binding.
Journal of Chemical Information and Modeling 08/2010; 50(8):1451-65. · 4.68 Impact Factor
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ABSTRACT: We identified three heterozygous nonsynonymous single nucleotide polymorphisms in the small heterodimer partner (SHP, NROB2) gene in normal subjects and CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy)-like patients, including two novel missense mutations (p.R38H, p.K170N) and one of the previously reported polymorphism (p.G171A). Four novel heterozygous mutations were also identified in the intron ((Intron)1265T-->A), 3'-untranslated region ((3'-UTR)101C-->G, (3'-UTR)186T-->C), and promoter ((Pro)-423C-->T) of the SHP gene. The exonic R38H and K170N mutants exhibited impaired nuclear translocation. K170N made SHP more susceptible to ubiquitination mediated degradation and blocked SHP acetylation, which displayed lost repressive activity on its interacting partners ERRgamma and HNF4alpha but not LRH-1. In contrast, G171A increased SHP mRNA and protein expression and maintained normal function. In general, the interaction of SHP mutants with LRH-1 and EID1 was enhanced. K170N also markedly impaired the recruitment of SHP, HNF4alpha, HDAC1, and HDAC3 to the apoCIII promoter. Molecular dynamics simulations of SHP showed that G171A stabilized the nuclear receptor boxes, whereas K170N promoted the conformational destabilization of all the structural elements of the receptor. This study suggests that genetic variations in SHP are common among human subjects and the Lys-170 residue plays a key role in controlling SHP ubiquitination and acetylation associated with SHP protein stability and repressive function.
Journal of Biological Chemistry 08/2010; 285(32):24871-81. · 4.77 Impact Factor
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ABSTRACT: We identified three heterozygous nonsynonymous single nucleotide polymorphisms in the small heterodimer partner (SHP, NROB2) gene in normal subjects and CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy)-like
patients, including two novel missense mutations (p.R38H, p.K170N) and one of the previously reported polymorphism (p.G171A).
Four novel heterozygous mutations were also identified in the intron (Intron1265T→A), 3′-untranslated region (3′-UTR101C→G, 3′-UTR186T→C), and promoter (Pro-423C→T) of the SHP gene. The exonic R38H and K170N mutants exhibited impaired nuclear translocation. K170N made SHP more
susceptible to ubiquitination mediated degradation and blocked SHP acetylation, which displayed lost repressive activity on
its interacting partners ERRγ and HNF4α but not LRH-1. In contrast, G171A increased SHP mRNA and protein expression and maintained
normal function. In general, the interaction of SHP mutants with LRH-1 and EID1 was enhanced. K170N also markedly impaired
the recruitment of SHP, HNF4α, HDAC1, and HDAC3 to the apoCIII promoter. Molecular dynamics simulations of SHP showed that
G171A stabilized the nuclear receptor boxes, whereas K170N promoted the conformational destabilization of all the structural
elements of the receptor. This study suggests that genetic variations in SHP are common among human subjects and the Lys-170
residue plays a key role in controlling SHP ubiquitination and acetylation associated with SHP protein stability and repressive
function.
Journal of Biological Chemistry 08/2010; 285(32):24871-24881. · 4.77 Impact Factor
