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Characterization of the First Animal Toxin Acting as an Antagonist on AT1 Receptor. Int J Mol Sci 2023; 24:ijms24032330. [PMID: 36768653 PMCID: PMC9916866 DOI: 10.3390/ijms24032330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 01/26/2023] Open
Abstract
The renin-angiotensin system (RAS) is one of the main regulatory systems of cardiovascular homeostasis. It is mainly composed of angiotensin-converting enzyme (ACE) and angiotensin II receptors AT1 and AT2. ACE and AT1 are targets of choice for the treatment of hypertension, whereas the AT2 receptor is still not exploited due to the lack of knowledge of its physiological properties. Peptide toxins from venoms display multiple biological functions associated with varied chemical and structural properties. If Brazilian viper toxins have been described to inhibit ACE, no animal toxin is known to act on AT1/AT2 receptors. We screened a library of toxins on angiotensin II receptors with a radioligand competition binding assay. Functional characterization of the selected toxin was conducted by measuring second messenger production, G-protein activation and β-arrestin 2 recruitment using bioluminescence resonance energy transfer (BRET) based biosensors. We identified one original toxin, A-CTX-cMila, which is a 7-residues cyclic peptide from Conus miliaris with no homology sequence with known angiotensin peptides nor identified toxins, displaying a 100-fold selectivity for AT1 over AT2. This toxin shows a competitive antagonism mode of action on AT1, blocking Gαq, Gαi3, GαoA, β-arrestin 2 pathways and ERK1/2 activation. These results describe the first animal toxin active on angiotensin II receptors.
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Al‐Zaid B, Chacko S, Ezeamuzie CI, Bünemann M, Krasel C, Karimian T, Lanzerstorfer P, Al‐Sabah S. Differential effects of glucose-dependent insulinotropic polypeptide receptor/glucagon-like peptide-1 receptor heteromerization on cell signaling when expressed in HEK-293 cells. Pharmacol Res Perspect 2022; 10:e01013. [PMID: 36177761 PMCID: PMC9523454 DOI: 10.1002/prp2.1013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 09/12/2022] [Indexed: 12/15/2022] Open
Abstract
The incretin hormones: glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are important regulators of many aspects of metabolism including insulin secretion. Their receptors (GIPR and GLP-1R) are closely related members of the secretin class of G-protein-coupled receptors. As both receptors are expressed on pancreatic β-cells there is at least the hypothetical possibility that they may form heteromers. In the present study, we investigated GIPR/GLP-1R heteromerization and the impact of GIPR on GLP-1R-mediated signaling and vice versa in HEK-293 cells. Real-time fluorescence resonance energy transfer (FRET) and bioluminescence resonance energy transfer (BRET) saturation experiments confirm that GLP-1R and GIPR form heteromers. Stimulation with 1 μM GLP-1 caused an increase in both FRET and BRET ratio, whereas stimulation with 1 μM GIP caused a decrease. The only other ligand tested to cause a significant change in BRET signal was the GLP-1 metabolite, GLP-1 (9-36). GIPR expression had no significant effect on mini-Gs recruitment to GLP-1R but significantly inhibited GLP-1 stimulated mini-Gq and arrestin recruitment. In contrast, the presence of GLP-1R improved GIP stimulated mini-Gs and mini-Gq recruitment to GIPR. These data support the hypothesis that GIPR and GLP-1R form heteromers with differential consequences on cell signaling.
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Affiliation(s)
- Bashaier Al‐Zaid
- Department of Pharmacology and Toxicology, Faculty of MedicineKuwait UniversityKuwait CityKuwait
| | - Siby Chacko
- Department of Pharmacology and Toxicology, Faculty of MedicineKuwait UniversityKuwait CityKuwait
| | | | - Moritz Bünemann
- School of Pharmacy, Institute for Pharmacology and ToxicologyThe Philipps University of MarburgMarburgGermany
| | - Cornelius Krasel
- School of Pharmacy, Institute for Pharmacology and ToxicologyThe Philipps University of MarburgMarburgGermany
| | - Tina Karimian
- University of Applied Sciences Upper Austria, School of EngineeringWelsAustria
| | - Peter Lanzerstorfer
- University of Applied Sciences Upper Austria, School of EngineeringWelsAustria
| | - Suleiman Al‐Sabah
- Department of Pharmacology and Toxicology, Faculty of MedicineKuwait UniversityKuwait CityKuwait
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McGlone ER, Ansell TB, Dunsterville C, Song W, Carling D, Tomas A, Bloom SR, Sansom MSP, Tan T, Jones B. Hepatocyte cholesterol content modulates glucagon receptor signalling. Mol Metab 2022; 63:101530. [PMID: 35718339 PMCID: PMC9254120 DOI: 10.1016/j.molmet.2022.101530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 06/13/2022] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To determine whether glucagon receptor (GCGR) actions are modulated by cellular cholesterol levels. METHODS We determined the effects of experimental cholesterol depletion and loading on glucagon-mediated cAMP production, ligand internalisation and glucose production in human hepatoma cells, mouse and human hepatocytes. GCGR interactions with lipid bilayers were explored using coarse-grained molecular dynamic simulations. Glucagon responsiveness was measured in mice fed a high cholesterol diet with or without simvastatin to modulate hepatocyte cholesterol content. RESULTS GCGR cAMP signalling was reduced by higher cholesterol levels across different cellular models. Ex vivo glucagon-induced glucose output from mouse hepatocytes was enhanced by simvastatin treatment. Mice fed a high cholesterol diet had increased hepatic cholesterol and a blunted hyperglycaemic response to glucagon, both of which were partially reversed by simvastatin. Simulations identified likely membrane-exposed cholesterol binding sites on the GCGR, including a site where cholesterol is a putative negative allosteric modulator. CONCLUSIONS Our results indicate that cellular cholesterol content influences glucagon sensitivity and indicate a potential molecular basis for this phenomenon. This could be relevant to the pathogenesis of non-alcoholic fatty liver disease, which is associated with both hepatic cholesterol accumulation and glucagon resistance.
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Affiliation(s)
- Emma Rose McGlone
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom; Department of Surgery and Cancer, Imperial College London, London W12 0NN, United Kingdom.
| | - T Bertie Ansell
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
| | - Cecilia Dunsterville
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom.
| | - Wanling Song
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
| | - David Carling
- Cellular Stress Research Group, MRC London Institute of Medical Sciences, Imperial College London, London W12 0NN, United Kingdom.
| | - Alejandra Tomas
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom.
| | - Stephen R Bloom
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom.
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
| | - Tricia Tan
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom.
| | - Ben Jones
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom.
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Chen H, Zhang S, Zhang X, Liu H. QR code model: a new possibility for GPCR phosphorylation recognition. Cell Commun Signal 2022; 20:23. [PMID: 35236365 PMCID: PMC8889771 DOI: 10.1186/s12964-022-00832-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/23/2022] [Indexed: 12/13/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are the largest family of membrane proteins in the human body and are responsible for accurately transmitting extracellular information to cells. Arrestin is an important member of the GPCR signaling pathway. The main function of arrestin is to assist receptor desensitization, endocytosis and signal transduction. In these processes, the recognition and binding of arrestin to phosphorylated GPCRs is fundamental. However, the mechanism by which arrestin recognizes phosphorylated GPCRs is not fully understood. The GPCR phosphorylation recognition "bar code model" and "flute" model describe the basic process of receptor phosphorylation recognition in terms of receptor phosphorylation sites, arrestin structural changes and downstream signaling. These two models suggest that GPCR phosphorylation recognition is a process involving multiple factors. This process can be described by a "QR code" model in which ligands, GPCRs, G protein-coupled receptor kinase, arrestin, and phosphorylation sites work together to determine the biological functions of phosphorylated receptors. Video Abstract.
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Affiliation(s)
- Hao Chen
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, 10 Xitoutiao, You An Men Street, Beijing, 100069, People's Republic of China
| | - Suli Zhang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, 10 Xitoutiao, You An Men Street, Beijing, 100069, People's Republic of China.,Beijing Key Laboratory of Metabolic Disorders Related Cardiovascular Disease, Capital Medical University, Beijing, 100069, People's Republic of China
| | - Xi Zhang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, 10 Xitoutiao, You An Men Street, Beijing, 100069, People's Republic of China
| | - Huirong Liu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, 10 Xitoutiao, You An Men Street, Beijing, 100069, People's Republic of China. .,Beijing Key Laboratory of Metabolic Disorders Related Cardiovascular Disease, Capital Medical University, Beijing, 100069, People's Republic of China.
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Abstract
PURPOSE Our understanding of thyroid-associated ophthalmopathy (TAO, A.K.A Graves' orbitopathy, thyroid eye disease) has advanced substantially, since one of us (TJS) wrote the 2010 update on TAO, appearing in this journal. METHODS PubMed was searched for relevant articles. RESULTS Recent insights have resulted from important studies conducted by many different laboratory groups around the World. A clearer understanding of autoimmune diseases in general and TAO specifically emerged from the use of improved research methodologies. Several key concepts have matured over the past decade. Among them, those arising from the refinement of mouse models of TAO, early stage investigation into restoring immune tolerance in Graves' disease, and a hard-won acknowledgement that the insulin-like growth factor-I receptor (IGF-IR) might play a critical role in the development of TAO, stand out as important. The therapeutic inhibition of IGF-IR has blossomed into an effective and safe medical treatment. Teprotumumab, a β-arrestin biased agonist monoclonal antibody inhibitor of IGF-IR has been studied in two multicenter, double-masked, placebo-controlled clinical trials demonstrated both effectiveness and a promising safety profile in moderate-to-severe, active TAO. Those studies led to the approval by the US FDA of teprotumumab, currently marketed as Tepezza for TAO. We have also learned far more about the putative role that CD34+ fibrocytes and their derivatives, CD34+ orbital fibroblasts, play in TAO. CONCLUSION The past decade has been filled with substantial scientific advances that should provide the necessary springboard for continually accelerating discovery over the next 10 years and beyond.
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Affiliation(s)
- E J Neag
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, Brehm Tower, 1000 Wall Street, Ann Arbor, MI, 48105, USA
- Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI, 48105, USA
- Michigan State University College of Osteopathic Medicine, East Lansing, MI, USA
| | - T J Smith
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, Brehm Tower, 1000 Wall Street, Ann Arbor, MI, 48105, USA.
- Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI, 48105, USA.
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Zamolodchikova TS, Tolpygo SM, Kotov AV. From Agonist to Antagonist: Modulation of the Physiological Action of Angiotensins by Protein Conjugation-Hemodynamics and Behavior. Front Pharmacol 2021; 12:772217. [PMID: 34803713 PMCID: PMC8595096 DOI: 10.3389/fphar.2021.772217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 09/23/2021] [Indexed: 11/18/2022] Open
Affiliation(s)
- Tatyana S Zamolodchikova
- Physiology of Motivation Laboratory, P. K. Anokhin Institute of Normal Physiology, Moscow, Russia
| | - Svetlana M Tolpygo
- Physiology of Motivation Laboratory, P. K. Anokhin Institute of Normal Physiology, Moscow, Russia
| | - Alexander V Kotov
- Physiology of Motivation Laboratory, P. K. Anokhin Institute of Normal Physiology, Moscow, Russia
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McGlone ER, Manchanda Y, Jones B, Pickford P, Inoue A, Carling D, Bloom SR, Tan T, Tomas A. Receptor Activity-Modifying Protein 2 (RAMP2) alters glucagon receptor trafficking in hepatocytes with functional effects on receptor signalling. Mol Metab 2021; 53:101296. [PMID: 34271220 PMCID: PMC8363841 DOI: 10.1016/j.molmet.2021.101296] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 07/01/2021] [Accepted: 07/09/2021] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVES Receptor Activity-Modifying Protein 2 (RAMP2) is a chaperone protein which allosterically binds to and interacts with the glucagon receptor (GCGR). The aims of this study were to investigate the effects of RAMP2 on GCGR trafficking and signalling in the liver, where glucagon (GCG) is important for carbohydrate and lipid metabolism. METHODS Subcellular localisation of GCGR in the presence and absence of RAMP2 was investigated using confocal microscopy, trafficking and radioligand binding assays in human embryonic kidney (HEK293T) and human hepatoma (Huh7) cells. Mouse embryonic fibroblasts (MEFs) lacking the Wiskott-Aldrich Syndrome protein and scar homologue (WASH) complex and the trafficking inhibitor monensin were used to investigate the effect of halted recycling of internalised proteins on GCGR subcellular localisation and signalling in the absence of RAMP2. NanoBiT complementation and cyclic AMP assays were used to study the functional effect of RAMP2 on the recruitment and activation of GCGR signalling mediators. Response to hepatic RAMP2 upregulation in lean and obese adult mice using a bespoke adeno-associated viral vector was also studied. RESULTS GCGR is predominantly localised at the plasma membrane in the absence of RAMP2 and exhibits remarkably slow internalisation in response to agonist stimulation. Rapid intracellular accumulation of GCG-stimulated GCGR in cells lacking the WASH complex or in the presence of monensin indicates that activated GCGR undergoes continuous cycles of internalisation and recycling, despite apparent GCGR plasma membrane localisation up to 40 min post-stimulation. Co-expression of RAMP2 induces GCGR internalisation both basally and in response to agonist stimulation. The intracellular retention of GCGR in the presence of RAMP2 confers a bias away from β-arrestin-2 recruitment coupled with increased activation of Gαs proteins at endosomes. This is associated with increased short-term efficacy for glucagon-stimulated cAMP production, although long-term signalling is dampened by increased receptor lysosomal targeting for degradation. Despite these signalling effects, only a minor disturbance of carbohydrate metabolism was observed in mice with upregulated hepatic RAMP2. CONCLUSIONS By retaining GCGR intracellularly, RAMP2 alters the spatiotemporal pattern of GCGR signalling. Further exploration of the effects of RAMP2 on GCGR in vivo is warranted.
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Affiliation(s)
- Emma Rose McGlone
- Section of Endocrinology and Investigative Medicine, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Yusman Manchanda
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Ben Jones
- Section of Endocrinology and Investigative Medicine, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Phil Pickford
- Section of Endocrinology and Investigative Medicine, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - David Carling
- MRC London Institute of Medical Sciences, Imperial College London, London, UK
| | - Stephen R Bloom
- Section of Endocrinology and Investigative Medicine, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Tricia Tan
- Section of Endocrinology and Investigative Medicine, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK.
| | - Alejandra Tomas
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK.
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Abstract
Gonadotropins are glycoprotein sex hormones regulating development and reproduction and bind to specific G protein–coupled receptors expressed in the gonads. Their effects on multiple signaling cascades and intracellular events have recently been characterized using novel technological and scientific tools. The impact of allosteric modulators on gonadotropin signaling, the role of sugars linked to the hormone backbone, the detection of endosomal compartments supporting signaling modules, and the dissection of different effects mediated by these molecules are areas that have advanced significantly in the last decade. The classic view providing the exclusive activation of the cAMP/protein kinase A (PKA) and the steroidogenic pathway by these hormones has been expanded with the addition of novel signaling cascades as determined by high-resolution imaging techniques. These new findings provided new potential therapeutic applications. Despite these improvements, unanswered issues of gonadotropin physiology, such as the intrinsic pro-apoptotic potential to these hormones, the existence of receptors assembled as heteromers, and their expression in extragonadal tissues, remain to be studied. Elucidating these issues is a challenge for future research.
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Affiliation(s)
- Livio Casarini
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via G. Campi 287, 41125 Modena, Italy
- Center for Genomic Research, University of Modena and Reggio Emilia, Via G. Campi 287, 41125 Modena, Italy
| | - Manuela Simoni
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via G. Campi 287, 41125 Modena, Italy
- Center for Genomic Research, University of Modena and Reggio Emilia, Via G. Campi 287, 41125 Modena, Italy
- Unit of Endocrinology, Department of Medical Specialties, Azienda Ospedaliero-Universitaria di Modena, Via P. Giardini 1355, 41126 Modena, Italy
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Zariñán T, Mayorga J, Jardón-Valadez E, Gutiérrez-Sagal R, Maravillas-Montero JL, Mejía-Domínguez NR, Martínez-Luis I, Yacini-Torres OG, Cravioto MDC, Reiter E, Ulloa-Aguirre A. A Novel Mutation in the FSH Receptor (I423T) Affecting Receptor Activation and Leading to Primary Ovarian Failure. J Clin Endocrinol Metab 2021; 106:e534-e550. [PMID: 33119067 DOI: 10.1210/clinem/dgaa782] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Indexed: 12/13/2022]
Abstract
CONTEXT Follicle-stimulating hormone (FSH) plays an essential role in gonadal function. Loss-of-function mutations in the follicle-stimulating hormone receptor (FSHR) are an infrequent cause of primary ovarian failure. OBJECTIVE To analyze the molecular physiopathogenesis of a novel mutation in the FSHR identified in a woman with primary ovarian failure, employing in vitro and in silico approaches, and to compare the features of this dysfunctional receptor with those shown by the trafficking-defective D408Y FSHR mutant. METHODS Sanger sequencing of the FSHR cDNA was applied to identify the novel mutation. FSH-stimulated cyclic adenosine monophosphate (cAMP) production, ERK1/2 phosphorylation, and desensitization were tested in HEK293 cells. Receptor expression was analyzed by immunoblotting, receptor-binding assays, and flow cytometry. Molecular dynamics simulations were performed to determine the in silico behavior of the mutant FSHRs. RESULTS A novel missense mutation (I423T) in the second transmembrane domain of the FSHR was identified in a woman with normal pubertal development but primary amenorrhea. The I423T mutation slightly impaired plasma membrane expression of the mature form of the receptor and severely impacted on cAMP/protein kinase A signaling but much less on β-arrestin-dependent ERK1/2 phosphorylation. Meanwhile, the D408Y mutation severely affected membrane expression, with most of the FSH receptor located intracellularly, and both signal readouts tested. Molecular dynamics simulations revealed important functional disruptions in both mutant FSHRs, mainly the loss of interhelical connectivity in the D408Y FSHR. CONCLUSIONS Concurrently, these data indicate that conformational differences during the inactive and active states account for the distinct expression levels, differential signaling, and phenotypic expression of the I423T and D408Y mutant FSHRs.
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Affiliation(s)
- Teresa Zariñán
- Red de Apoyo a la Investigación, National University of Mexico-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Julio Mayorga
- Department of Reproductive Biology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Eduardo Jardón-Valadez
- Departamento de Recursos de la Tierra, Universidad Autónoma Metropolitana, Unidad Lerma, Lerma, Edo. de Mexico, Mexico
| | - Rubén Gutiérrez-Sagal
- Red de Apoyo a la Investigación, National University of Mexico-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - José Luis Maravillas-Montero
- Red de Apoyo a la Investigación, National University of Mexico-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Nancy R Mejía-Domínguez
- Red de Apoyo a la Investigación, National University of Mexico-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Iván Martínez-Luis
- Red de Apoyo a la Investigación, National University of Mexico-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Omar G Yacini-Torres
- Red de Apoyo a la Investigación, National University of Mexico-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Ma-Del-Carmen Cravioto
- Department of Reproductive Biology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Eric Reiter
- Physiologie de la Reproduction et des Comportements (PRC), Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Centre National de la Recherche Scientifique (CNRS), Université de Tours, Tours, France
| | - Alfredo Ulloa-Aguirre
- Red de Apoyo a la Investigación, National University of Mexico-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
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Dissecting the structural features of β-arrestins as multifunctional proteins. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2021; 1869:140603. [PMID: 33421644 DOI: 10.1016/j.bbapap.2021.140603] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/21/2020] [Accepted: 01/04/2021] [Indexed: 02/08/2023]
Abstract
β-arrestins bind active G protein-coupled receptors (GPCRs) and play a crucial role in receptor desensitization and internalization. The classical paradigm of arrestin function has been expanded with the identification of many non-receptor-binding partners, which indicated the multifunctional role of β-arrestins in cellular functions. To elucidate the molecular mechanism of β-arrestin-mediated signaling, the structural features of β-arrestins were investigated using X-ray crystallography and cryogenic electron microscopy (cryo-EM). However, the intrinsic conformational flexibility of β-arrestins hampers the elucidation of structural interactions between β-arrestins and their binding partners using conventional structure determination tools. Therefore, structural information obtained using complementary structure analysis techniques would be necessary in combination with X-ray crystallography and cryo-EM data. In this review, we describe how β-arrestins interact with their binding partners from a structural point of view, as elucidated by both traditional methods (X-ray crystallography and cryo-EM) and complementary structure analysis techniques.
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11
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Yang LK, Hou ZS, Tao YX. Biased signaling in naturally occurring mutations of G protein-coupled receptors associated with diverse human diseases. Biochim Biophys Acta Mol Basis Dis 2021; 1867:165973. [PMID: 32949766 PMCID: PMC7722056 DOI: 10.1016/j.bbadis.2020.165973] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/07/2020] [Accepted: 09/14/2020] [Indexed: 12/15/2022]
Abstract
G protein-coupled receptors (GPCRs) play critical roles in transmitting a variety of extracellular signals into the cells and regulate diverse physiological functions. Naturally occurring mutations that result in dysfunctions of GPCRs have been known as the causes of numerous diseases. Significant progresses have been made in elucidating the pathophysiology of diseases caused by mutations. The multiple intracellular signaling pathways, such as G protein-dependent and β-arrestin-dependent signaling, in conjunction with recent advances on biased agonism, have broadened the view on the molecular mechanism of disease pathogenesis. This review aims to briefly discuss biased agonism of GPCRs (biased ligands and biased receptors), summarize the naturally occurring GPCR mutations that cause biased signaling, and propose the potential pathophysiological relevance of biased mutant GPCRs associated with various endocrine diseases.
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Affiliation(s)
- Li-Kun Yang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Zhi-Shuai Hou
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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12
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Krause G, Eckstein A, Schülein R. Modulating TSH Receptor Signaling for Therapeutic Benefit. Eur Thyroid J 2020; 9:66-77. [PMID: 33511087 PMCID: PMC7802447 DOI: 10.1159/000511871] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 10/01/2020] [Indexed: 12/14/2022] Open
Abstract
Autoimmune thyroid-stimulating antibodies are activating the thyrotropin receptor (TSHR) in both the thyroid and the eye, but different molecular mechanisms are induced in both organs, leading to Graves' disease (GD) and Graves' orbitopathy (GO), respectively. Therapy with anti-thyroid drugs to reduce hyperthyroidism (GD) by suppressing the biosynthesis of thyroid hormones has only an indirect effect on GO, since it does not causally address pathogenic TSHR activation itself. GO is thus very difficult to treat. The activated TSHR but also the cross-interacting insulin-like growth factor 1 receptor (IGF-1R) contribute to this issue. The TSHR is a heptahelical G-protein-coupled receptor, whereas the IGF-1R is a receptor tyrosine kinase. Despite these fundamental structural differences, both receptors are phosphorylated by G-protein receptor kinases, which enables β-arrestin binding. Arrestins mediate receptor internalization and also activate the mitogen-activated protein kinase pathway. Moreover, emerging results suggest that arrestin plays a critical role in the cross-interaction of the TSHR and the IGF-1R either in their common signaling pathway and/or during an indirect or potential TSHR/IGF-1R interaction. In this review, novel pharmacological strategies with allosteric small-molecule modulators to treat GO and GD on the level of the TSHR and/or the TSHR/IGF-1R cross-interaction will be discussed. Moreover, monoclonal antibody approaches targeting the TSHR or the IGF-1R and thereby preventing activation of either receptor will be presented. Another chapter addresses the immunomodulation to treat GO using TSHR-derived peptides targeting the human leukocyte antigen DR isotope (HLA-DR), which is a feasible approach to tackle GO, since HLA-DR and TSHR are overexpressed in orbital tissues of GO patients.
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Affiliation(s)
- Gerd Krause
- Structural Biology, Leibniz-Forschungsinstitut für molekulare Pharmakologie (FMP), Berlin, Germany
- *Gerd Krause, Structural Biology, Leibniz-Forschungsinstitut für molekulare Pharmakologie (FMP), Robert Rössle Strasse 10, DE–13125 Berlin (Germany),
| | - Anja Eckstein
- Department of Ophthalmology, University Hospital Essen, Essen, Germany
| | - Ralf Schülein
- Protein Trafficking, Leibniz-Forschungsinstitut für molekulare Pharmakologie (FMP), Berlin, Germany
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Drd2 biased agonist prevents neurodegeneration against NLRP3 inflammasome in Parkinson's disease model via a β-arrestin2-biased mechanism. Brain Behav Immun 2020; 90:259-271. [PMID: 32861720 DOI: 10.1016/j.bbi.2020.08.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 08/20/2020] [Accepted: 08/21/2020] [Indexed: 01/14/2023] Open
Abstract
Activated astrocytes secrete inflammatory cytokines such as interleukin-1β (IL-1β) into the extracellular milieu, damaging surrounding neurons and involving in the pathogenesis of neurodegenerative diseases, such as Parkinson's disease (PD). Dopamine receptor D2 (Drd2) expresses both in neurons and astrocytes, and neuronal Drd2 is a significant target in therapy of PD. Our previous study reveals that astrocytic Drd2 exerts anti-inflammatory effect via non-classical β-arrestin2 signaling in PD model. Therefore, seeking new biased ligands of Drd2 with better efficacy and fewer side effects to treat PD is desirable and meaningful. In the present study, we evaluated the effects of UNC9995, a novel biased Drd2 agonist on astrocyte-derived neuroinflammation and dopaminergic (DA) neuron degenerationin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD. We showed that UNC9995 rescued the TH+ neurons loss and inhibited glial cells activation in mouse substantia nigra in a Drd2 dependent manner. Focusing on astrocytes, we found UNC9995 shows a relatively safe concentration range and significantly suppresses astrocytic NLRP3 inflammasome activation induced by lipopolysaccharide plus ATP. Further study revealed that the anti-inflammatory effect of UNC9995 is independent of Drd2 / Gαi protein pathway. It activates β-arrestin2 by recruiting it to cell membrane. Critically, UNC9995 enhances β-arrestin2 interacting with NLRP3 to interfere inflammasome assembly, which consequently reduces IL-1β production. On the other hand, UNC9995 inhibits IL-1β-induced inflammatory pathway activation in DA neurons and rescues subsequent apoptosis via β-arrestin2 interacting with protein kinases, such as JNK and suppressing their phosphorylation. Furthermore, β-arrestin2 knockout abolishes the anti-inflammatory and neuroprotective effects of UNC9995 in PD mouse model, supporting that UNC9995 is a β-arrestin2-biased Drd2 agonist and revealing its novel function in PD treatment. Collectively, this work illustrates that Drd2 agonist UNC9995 prevents DA neuron degeneration in PD and provides a new strategy for developing the β-arrestin2-biased ligands in the therapy of NDDs.
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14
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Casarini L, Riccetti L, Paradiso E, Benevelli R, Lazzaretti C, Sperduti S, Melli B, Tagliavini S, Varani M, Trenti T, Morini D, Falbo A, Villani MT, Jonas KC, Simoni M. Two human menopausal gonadotrophin (hMG) preparations display different early signaling in vitro. Mol Hum Reprod 2020; 26:894-905. [PMID: 33084890 DOI: 10.1093/molehr/gaaa070] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/28/2020] [Indexed: 02/07/2023] Open
Abstract
Commercial hMG drugs are marketed for the treatment of infertility and consist of highly purified hormones acting on receptors expressed in target gonadal cells. Menopur® and Meriofert® are combined preparation of FSH and hCG and are compared in vitro herein. To this purpose, the molecular composition of the two drugs was analyzed by immunoassay. The formation of FSH receptor and LH/hCG receptor (FSHR; LHCGR) heteromer, intracellular Ca2+ and cAMP activation, β-arrestin 2 recruitment and the synthesis of progesterone and estradiol were evaluated in transfected HEK293 and human primary granulosa lutein cells treated by drugs administered within the pg-mg/ml concentration range. Molecular characterization revealed that Meriofert® has a higher FSH:hCG ratio than Menopur® which, in turn, displays the presence of LH molecules. While both drugs induced similar FSHR-LHCGR heteromeric formations and intracellular Ca2+ increase, Meriofert® had a higher potency than Menopur® in inducing a cAMP increase. Moreover, Meriofert® revealed a higher potency than Menopur® in recruiting β-arrestin 2, likely due to different FSH content modulating the tridimensional structure of FSHR-LHCGR-β-arrestin 2 complexes, as evidenced by a decrease in bioluminescence resonance energy transfer signal. This drug-specific activation of intracellular signaling pathways is consistent with the molecular composition of these preparations and impacts downstream progesterone and estradiol production, with Menopur® more potent than Meriofert® in inducing the synthesis of both the steroids. These findings are suggestive of distinct in-vivo activities of these preparations, but require cautious interpretation and further validation from clinical studies.
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Affiliation(s)
- Livio Casarini
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy.,Center for Genomic Research, University of Modena and Reggio Emilia, Modena 41125, Italy
| | - Laura Riccetti
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Elia Paradiso
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy.,International PhD School in Clinical and Experimental Medicine (CEM), University of Modena and Reggio Emilia, Modena 41125, Italy
| | - Riccardo Benevelli
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Clara Lazzaretti
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy.,International PhD School in Clinical and Experimental Medicine (CEM), University of Modena and Reggio Emilia, Modena 41125, Italy
| | - Samantha Sperduti
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy.,Center for Genomic Research, University of Modena and Reggio Emilia, Modena 41125, Italy
| | - Beatrice Melli
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Simonetta Tagliavini
- Department of Laboratory Medicine and Pathological Anatomy, Azienda USL. NOCSAE, Modena 41126, Italy
| | - Manuela Varani
- Department of Laboratory Medicine and Pathological Anatomy, Azienda USL. NOCSAE, Modena 41126, Italy
| | - Tommaso Trenti
- Department of Laboratory Medicine and Pathological Anatomy, Azienda USL. NOCSAE, Modena 41126, Italy
| | - Daria Morini
- Azienda Unità Sanitaria Locale-IRCCS di Reggio Emilia, Department of Obstetrics and Gynaecology, Fertility Center, ASMN, Reggio Emilia, Italy
| | - Angela Falbo
- Azienda Unità Sanitaria Locale-IRCCS di Reggio Emilia, Department of Obstetrics and Gynaecology, Fertility Center, ASMN, Reggio Emilia, Italy
| | - Maria Teresa Villani
- Azienda Unità Sanitaria Locale-IRCCS di Reggio Emilia, Department of Obstetrics and Gynaecology, Fertility Center, ASMN, Reggio Emilia, Italy
| | - Kim C Jonas
- Department of Women and Children's Health, School of Life course Sciences, King's College London, London SE1 1UL, UK
| | - Manuela Simoni
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy.,International PhD School in Clinical and Experimental Medicine (CEM), University of Modena and Reggio Emilia, Modena 41125, Italy.,Unit of Endocrinology, Department of Medical Specialties, Azienda Ospedaliero-Universitaria, 41126 Modena, Italy.,PRC, INRA, CNRS, IFCE, Université de Tours, 37380 Nouzilly, France
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15
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Al-Sabah S, Adi L, Bünemann M, Krasel C. The Effect of Cell Surface Expression and Linker Sequence on the Recruitment of Arrestin to the GIP Receptor. Front Pharmacol 2020; 11:1271. [PMID: 32903502 PMCID: PMC7438548 DOI: 10.3389/fphar.2020.01271] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 07/31/2020] [Indexed: 01/28/2023] Open
Abstract
The glucose-dependent insulinotropic polypeptide (GIP) and the glucagon-like peptide-1 (GLP-1) receptor are important targets in the treatment of both type 2 diabetes mellitus (T2DM) and obesity. Originally identified for their role in desensitization, internalization and recycling of G protein-coupled receptors (GPCRs), arrestins have since been shown to act as scaffolding proteins that allow GPCRs to signal in a G protein-independent manner. While GLP-1R has been reported to interact with arrestins, this aspect of cell signaling remains controversial for GIPR. Using a (FRET)-based assay we have previously shown that yellow fluorescent protein (YFP)-labeled GIPR does not recruit arrestin. This GIPR-YFP construct contained a 10 amino acid linker between the receptor and a XbaI restriction site upstream of the YFP. This linker was not present in the modified GIPR-SYFP2 used in subsequent FRET and bioluminescence resonance energy transfer (BRET) assays. However, its removal results in the introduction of a serine residue adjacent to the end of GIPR’s C-terminal tail which could potentially be a phosphorylation site. The resulting receptor was indeed able to recruit arrestin. To find out whether the serine/arginine (SR) coded by the XbaI site was indeed the source of the problem, it was substituted with glycine/glycine (GG) by site-directed mutagenesis. This substitution abolished arrestin recruitment in the BRET assay but only significantly reduced it in the FRET assay. In addition, we show that the presence of a N-terminal FLAG epitope and influenza hemagglutinin signal peptide were also required to detect arrestin recruitment to the GIPR, most likely by increasing receptor cell surface expression. These results demonstrate how arrestin recruitment assay configuration can dramatically alter the result. This becomes relevant when drug discovery programs aim to identify ligands with “biased agonist” properties.
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Affiliation(s)
- Suleiman Al-Sabah
- Department of Pharmacology and Toxicology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Lobna Adi
- Department of Pharmacology and Toxicology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Moritz Bünemann
- School of Pharmacy, Institute for Pharmacology and Toxicology, The Philipps University of Marburg, Marburg, Germany
| | - Cornelius Krasel
- School of Pharmacy, Institute for Pharmacology and Toxicology, The Philipps University of Marburg, Marburg, Germany
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16
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Zariñán T, Butnev VY, Gutiérrez-Sagal R, Maravillas-Montero JL, Martínez-Luis I, Mejía-Domínguez NR, Juárez-Vega G, Bousfield GR, Ulloa-Aguirre A. In Vitro Impact of FSH Glycosylation Variants on FSH Receptor-stimulated Signal Transduction and Functional Selectivity. J Endocr Soc 2020; 4:bvaa019. [PMID: 32342021 PMCID: PMC7175721 DOI: 10.1210/jendso/bvaa019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/14/2020] [Indexed: 12/21/2022] Open
Abstract
FSH exists as different glycoforms that differ in glycosylation of the hormone-specific β-subunit. Tetra-glycosylated FSH (FSH24) and hypo-glycosylated FSH (FSH18/21) are the most abundant glycoforms found in humans. Employing distinct readouts in HEK293 cells expressing the FSH receptor, we compared signaling triggered by human pituitary FSH preparations (FSH18/21 and FSH24) as well as by equine FSH (eFSH), and human recombinant FSH (recFSH), each exhibiting distinct glycosylation patterns. The potency in eliciting cAMP production was greater for eFSH than for FSH18/21, FSH24, and recFSH, whereas in the ERK1/2 activation readout, potency was highest for FSH18/21 followed by eFSH, recFSH, and FSH24. In β-arrestin1/2 CRISPR/Cas9 HEK293-KO cells, FSH18/21 exhibited a preference toward β-arrestin-mediated ERK1/2 activation as revealed by a drastic decrease in pERK during the first 15-minute exposure to this glycoform. Exposure of β-arrestin1/2 KO cells to H89 additionally decreased pERK1/2, albeit to a significantly lower extent in response to FSH18/21. Concurrent silencing of β-arrestin and PKA signaling, incompletely suppressed pERK response to FSH glycoforms, suggesting that pathways other than those dependent on Gs-protein and β-arrestins also contribute to FSH-stimulated pERK1/2. All FSH glycoforms stimulated intracellular Ca2+ (iCa2+) accumulation through both influx from Ca2+ channels and release from intracellular stores; however, iCa2+ in response to FSH18/21 depended more on the latter, suggesting differences in mechanisms through which glycoforms promote iCa2+ accumulation. These data indicate that FSH glycosylation plays an important role in defining not only the intensity but also the functional selectivity for the mechanisms leading to activation of distinct signaling cascades.
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Affiliation(s)
- Teresa Zariñán
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México (UNAM)-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Viktor Y Butnev
- Department of Biological Sciences, Wichita State University, Wichita, Kansas, USA
| | - Rubén Gutiérrez-Sagal
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México (UNAM)-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - José Luis Maravillas-Montero
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México (UNAM)-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Iván Martínez-Luis
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México (UNAM)-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Nancy R Mejía-Domínguez
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México (UNAM)-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Guillermo Juárez-Vega
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México (UNAM)-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - George R Bousfield
- Department of Biological Sciences, Wichita State University, Wichita, Kansas, USA
| | - Alfredo Ulloa-Aguirre
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México (UNAM)-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
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17
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Pharmacological characterization of mono-, dual- and tri-peptidic agonists at GIP and GLP-1 receptors. Biochem Pharmacol 2020; 177:114001. [PMID: 32360365 DOI: 10.1016/j.bcp.2020.114001] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 04/24/2020] [Indexed: 12/13/2022]
Abstract
Glucose-dependent insulinotropic peptide (GIP) is an incretin hormone with physiological roles in adipose tissue, the central nervous system and bone metabolism. While selective ligands for GIP receptor (GIPR) have not been advanced for disease treatment, dual and triple agonists of GIPR, in conjunction with that of glucagon-like peptide-1 (GLP-1) and glucagon receptors, are currently in clinical trials, with an expectation of enhanced efficacy beyond that of GLP-1 receptor (GLP-1R) agonist monotherapy for diabetic patients. Consequently, it is important to understand the pharmacological behavior of such drugs. In this study, we have explored signaling pathway specificity and the potential for biased agonism of mono-, dual- and tri-agonists of GIPR using human embryonic kidney 293 (HEK293) cells recombinantly expressing human GIPR or GLP-1R. Compared to GIP(1-42), the GIPR mono-agonists Pro3GIP and Lys3GIP are biased towards ERK1/2 phosphorylation (pERK1/2) relative to cAMP accumulation at GIPR, whereas the triple agonist at GLP-1R/GCGR/GIPR is biased towards pERK1/2 relative to β-arrestin2 recruitment. Moreover, the dual GIPR/GLP-1R agonist, LY3298176, is biased towards pERK1/2 relative to cAMP accumulation at both GIPR and GLP-1R compared to their respective endogenous ligands. These data reveal novel pharmacological properties of potential therapeutic agents that may impact on diversity in clinical responses.
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18
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Khalid E, Chang JP. β-Arrestin-dependent signaling in GnRH control of hormone secretion from goldfish gonadotrophs and somatotrophs. Gen Comp Endocrinol 2020; 287:113340. [PMID: 31778712 DOI: 10.1016/j.ygcen.2019.113340] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/20/2019] [Accepted: 11/22/2019] [Indexed: 12/17/2022]
Abstract
In goldfish, two native isoforms of gonadotropin-releasing hormone (GnRH2 and GnRH3) stimulate luteinizing hormone (LH) and growth hormone (GH) release from pituitary cells through activation of cell-surface GnRH-receptors (GnRHRs) on gonadotrophs and somatotrophs. Interestingly, GnRH2 and GnRH3 induce LH and GH release via non-identical post-receptor signal transduction pathways in a ligand- and cell-type-selective manner. In this study, we examined the involvement of β-arrestins in the control of GnRH-induced LH and GH secretion from dispersed goldfish pituitary cells. Treatment with Barbadin, which interferes with β-arrestin and β2-adaptin subunit interaction, reduced LH responses to GnRH2 and GnRH3, as well as GH responses to GnRH2; but enhanced GnRH3-induced GH secretion. Barbadin also had positive influences on basal hormone release, and basal GH release in particular, as well as basal activity of extracellular signal-regulated kinase (ERK) and GnRH-induced ERK activation. These findings indicate that β-arrestins play permissive roles in the control of GnRH-stimulated LH release. However, in somatotrophs, β-arrestins, perhaps by mediating agonist-selective endosomal trafficking of engaged GnRHRs, participate in GnRH-isoform-specific GH release responses (stimulatory and inhibitory for GnRH2-GnRHR and GnRH3-GnRHR activation, respectively). The correlative stimulatory influences of Barbadin on basal hormone release and ERK activation suggest that β-arrestins may negatively regulate basal secretion through modulation of basal ERK activity. These results provide the first direct evidence of a role for β-arrestins in hormone secretion from an untransformed primary pituitary cell model, and establish these proteins as important receptor-proximal players in mediating functional selectivity downstream of goldfish GnRHRs.
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Affiliation(s)
- Enezi Khalid
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G2E9, Canada
| | - John P Chang
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G2E9, Canada.
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19
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Tyurin-Kuzmin PA, Kalinina NI, Kulebyakin KY, Balatskiy AV, Sysoeva VY, Tkachuk VA. Angiotensin receptor subtypes regulate adipose tissue renewal and remodelling. FEBS J 2020; 287:1076-1087. [PMID: 31899581 DOI: 10.1111/febs.15200] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 12/14/2019] [Accepted: 01/02/2020] [Indexed: 12/20/2022]
Abstract
Obesity is often associated with high systemic and local renin-angiotensin system (RAS) activity in adipose tissue. Adipose-derived mesenchymal stem/stromal cells (ADSCs), responsible for adipose tissue growth upon high-fat diet, express multiple angiotensin II receptor isoforms, including angiotensin II type 1 receptor (AT1 R), angiotensin II type 2 receptor (AT2 R), Mas and Mas-related G protein-coupled receptor D. Although AT1 R is expressed on most ADSCs, other angiotensin receptors are co-expressed on a small subpopulation of the cells, a phenomenon that results in a complex response pattern. Following AT1 R activation, the effects are transient due to rapid receptor internalisation. This short-lived effect can be prevented by heteromerisation with AT2 R, a particularly important strategy for the regulation of ADSC differentiation and secretory activity. Heteromeric AT2 R might be especially important for the generation of thermogenic beige adipocytes. This review summarises current data regarding the regulation of adipose tissue renewal and particularly ADSC adipogenic differentiation and secretory activity by RAS, with an emphasis on AT2 R and its effects. We reveal a new scheme that implicates AT2 R into the regulation of ADSC hormonal sensitivity.
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Affiliation(s)
- Pyotr A Tyurin-Kuzmin
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Lomonosov Moscow State University, Russia
| | - Natalia I Kalinina
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Lomonosov Moscow State University, Russia
| | - Konstantin Y Kulebyakin
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Lomonosov Moscow State University, Russia
| | - Alexander V Balatskiy
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Lomonosov Moscow State University, Russia.,Department of Clinical Diagnostics, Medical Centre, Lomonosov Moscow State University, Russia.,National Medical Research Centre in Cardiology, Russia
| | - Veronika Y Sysoeva
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Lomonosov Moscow State University, Russia
| | - Vsevolod A Tkachuk
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Lomonosov Moscow State University, Russia.,National Medical Research Centre in Cardiology, Russia
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20
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Smith TJ, Janssen JAMJL. Insulin-like Growth Factor-I Receptor and Thyroid-Associated Ophthalmopathy. Endocr Rev 2019; 40:236-267. [PMID: 30215690 PMCID: PMC6338478 DOI: 10.1210/er.2018-00066] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 06/21/2018] [Indexed: 12/15/2022]
Abstract
Thyroid-associated ophthalmopathy (TAO) is a complex disease process presumed to emerge from autoimmunity occurring in the thyroid gland, most frequently in Graves disease (GD). It is disfiguring and potentially blinding, culminating in orbital tissue remodeling and disruption of function of structures adjacent to the eye. There are currently no medical therapies proven capable of altering the clinical outcome of TAO in randomized, placebo-controlled multicenter trials. The orbital fibroblast represents the central target for immune reactivity. Recent identification of fibroblasts that putatively originate in the bone marrow as monocyte progenitors provides a plausible explanation for why antigens, the expressions of which were once considered restricted to the thyroid, are detected in the TAO orbit. These cells, known as fibrocytes, express relatively high levels of functional TSH receptor (TSHR) through which they can be activated by TSH and the GD-specific pathogenic antibodies that underpin thyroid overactivity. Fibrocytes also express insulin-like growth factor I receptor (IGF-IR) with which TSHR forms a physical and functional signaling complex. Notably, inhibition of IGF-IR activity results in the attenuation of signaling initiated at either receptor. Some studies suggest that IGF-IR-activating antibodies are generated in GD, whereas others refute this concept. These observations served as the rationale for implementing a recently completed therapeutic trial of teprotumumab, a monoclonal inhibitory antibody targeting IGF-IR in TAO. Results of that trial in active, moderate to severe disease revealed dramatic and rapid reductions in disease activity and severity. The targeting of IGF-IR with specific biologic agents may represent a paradigm shift in the therapy of TAO.
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Affiliation(s)
- Terry J Smith
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, and Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan
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21
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Landomiel F, De Pascali F, Raynaud P, Jean-Alphonse F, Yvinec R, Pellissier LP, Bozon V, Bruneau G, Crépieux P, Poupon A, Reiter E. Biased Signaling and Allosteric Modulation at the FSHR. Front Endocrinol (Lausanne) 2019; 10:148. [PMID: 30930853 PMCID: PMC6425863 DOI: 10.3389/fendo.2019.00148] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 02/19/2019] [Indexed: 12/12/2022] Open
Abstract
Knowledge on G protein-coupled receptor (GPCRs) structure and mechanism of activation has profoundly evolved over the past years. The way drugs targeting this family of receptors are discovered and used has also changed. Ligands appear to bind a growing number of GPCRs in a competitive or allosteric manner to elicit balanced signaling or biased signaling (i.e., differential efficacy in activating or inhibiting selective signaling pathway(s) compared to the reference ligand). These novel concepts and developments transform our understanding of the follicle-stimulating hormone (FSH) receptor (FSHR) biology and the way it could be pharmacologically modulated in the future. The FSHR is expressed in somatic cells of the gonads and plays a major role in reproduction. When compared to classical GPCRs, the FSHR exhibits intrinsic peculiarities, such as a very large NH2-terminal extracellular domain that binds a naturally heterogeneous, large heterodimeric glycoprotein, namely FSH. Once activated, the FSHR couples to Gαs and, in some instances, to other Gα subunits. G protein-coupled receptor kinases and β-arrestins are also recruited to this receptor and account for its desensitization, trafficking, and intracellular signaling. Different classes of pharmacological tools capable of biasing FSHR signaling have been reported and open promising prospects both in basic research and for therapeutic applications. Here we provide an updated review of the most salient peculiarities of FSHR signaling and its selective modulation.
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22
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Yvinec R, Ayoub MA, De Pascali F, Crépieux P, Reiter E, Poupon A. Workflow Description to Dynamically Model β-Arrestin Signaling Networks. Methods Mol Biol 2019; 1957:195-215. [PMID: 30919356 DOI: 10.1007/978-1-4939-9158-7_13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Dynamic models of signaling networks allow the formulation of hypotheses on the topology and kinetic rate laws characterizing a given molecular network, in-depth exploration, and confrontation with kinetic biological data. Despite its standardization, dynamic modeling of signaling networks still requires successive technical steps that need to be carefully performed. Here, we detail these steps by going through the mathematical and statistical framework. We explain how it can be applied to the understanding of β-arrestin-dependent signaling networks. We illustrate our methodology through the modeling of β-arrestin recruitment kinetics at the follicle-stimulating hormone (FSH) receptor supported by in-house bioluminescence resonance energy transfer (BRET) data.
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Affiliation(s)
- Romain Yvinec
- PRC, INRA, CNRS, IFCE, Université de Tours, 37380 Nouzilly, France.
| | - Mohammed Akli Ayoub
- PRC, INRA, CNRS, IFCE, Université de Tours, 37380 Nouzilly, France.,Biology Department, College of Science, United Arab Emirates University, PO BOX 15551, Al Ain, United Arab Emirates
| | | | - Pascale Crépieux
- PRC, INRA, CNRS, IFCE, Université de Tours, 37380 Nouzilly, France
| | - Eric Reiter
- PRC, INRA, CNRS, IFCE, Université de Tours, 37380 Nouzilly, France
| | - Anne Poupon
- PRC, INRA, CNRS, IFCE, Université de Tours, 37380 Nouzilly, France
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23
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GPCR drug discovery: integrating solution NMR data with crystal and cryo-EM structures. Nat Rev Drug Discov 2018; 18:59-82. [PMID: 30410121 DOI: 10.1038/nrd.2018.180] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The 826 G protein-coupled receptors (GPCRs) in the human proteome regulate key physiological processes and thus have long been attractive drug targets. With the crystal structures of more than 50 different human GPCRs determined over the past decade, an initial platform for structure-based rational design has been established for drugs that target GPCRs, which is currently being augmented with cryo-electron microscopy (cryo-EM) structures of higher-order GPCR complexes. Nuclear magnetic resonance (NMR) spectroscopy in solution is one of the key approaches for expanding this platform with dynamic features, which can be accessed at physiological temperature and with minimal modification of the wild-type GPCR covalent structures. Here, we review strategies for the use of advanced biochemistry and NMR techniques with GPCRs, survey projects in which crystal or cryo-EM structures have been complemented with NMR investigations and discuss the impact of this integrative approach on GPCR biology and drug discovery.
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Yvinec R, Crépieux P, Reiter E, Poupon A, Clément F. Advances in computational modeling approaches of pituitary gonadotropin signaling. Expert Opin Drug Discov 2018; 13:799-813. [DOI: 10.1080/17460441.2018.1501025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Romain Yvinec
- PRC, INRA, CNRS, IFCE, Université de Tours, Nouzilly, France
| | | | - Eric Reiter
- PRC, INRA, CNRS, IFCE, Université de Tours, Nouzilly, France
| | - Anne Poupon
- PRC, INRA, CNRS, IFCE, Université de Tours, Nouzilly, France
| | - Frédérique Clément
- Inria, Université Paris-Saclay, Palaiseau, France
- LMS, Ecole Polytechnique, CNRS, Université Paris-Saclay, Palaiseau, France
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Ulloa-Aguirre A, Reiter E, Crépieux P. FSH Receptor Signaling: Complexity of Interactions and Signal Diversity. Endocrinology 2018; 159:3020-3035. [PMID: 29982321 DOI: 10.1210/en.2018-00452] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 06/27/2018] [Indexed: 12/20/2022]
Abstract
FSH is synthesized in the pituitary by gonadotrope cells. By binding to and interacting with its cognate receptor [FSH receptor (FSHR)] in the gonads, this gonadotropin plays a key role in the control of gonadal function and reproduction. Upon activation, the FSHR undergoes conformational changes leading to transduction of intracellular signals, including dissociation of G protein complexes into components and activation of several associated interacting partners, which concertedly regulate downstream effectors. The canonical Gs/cAMP/protein kinase A pathway, considered for a long time as the sole effector of FSHR-mediated signaling, is now viewed as one of several mechanisms employed by this receptor to transduce intracellular signals in response to the FSH stimulus. This complex network of signaling pathways allows for a fine-tuning regulation of the gonadotropic stimulus, where activation/inhibition of its multiple components vary depending on the cell context, cell developmental stage, and concentration of associated receptors and corresponding ligands. Activation of these multiple signaling modules eventually converge to the hormone-integrated biological response, including survival, proliferation and differentiation of target cells, synthesis and secretion of paracrine/autocrine regulators, and, at the molecular level, functional selectivity and differential gene expression. In this mini-review, we discuss the complexity of FSHR-mediated intracellular signals activated in response to ligand stimulation. A better understanding of the signaling pathways involved in FSH action might potentially influence the development of new therapeutic strategies for reproductive disorders.
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Affiliation(s)
- Alfredo Ulloa-Aguirre
- Red de Apoyo a la Investigación, Universidad Nacional Autónoma de México-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Eric Reiter
- Biology and Bioinformatics of Signaling Systems Group, Unité Mixtes de Recherche 85, Unité Physiologie de la Reproduction et des Comportements, Institut National de la Recherche Agronomique, Nouzilly, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7247, Nouzilly, France
- Université François Rabelais, Nouzilly, France
| | - Pascale Crépieux
- Biology and Bioinformatics of Signaling Systems Group, Unité Mixtes de Recherche 85, Unité Physiologie de la Reproduction et des Comportements, Institut National de la Recherche Agronomique, Nouzilly, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7247, Nouzilly, France
- Université François Rabelais, Nouzilly, France
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Smith TJ. Challenges in Orphan Drug Development: Identification of Effective Therapy for Thyroid-Associated Ophthalmopathy. Annu Rev Pharmacol Toxicol 2018; 59:129-148. [PMID: 30044728 DOI: 10.1146/annurev-pharmtox-010617-052509] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Thyroid-associated ophthalmopathy (TAO), the ocular manifestation of Graves' disease, is a process in which orbital connective tissues and extraocular muscles undergo inflammation and remodeling. The condition seems to result from autoimmune responses to antigens shared by the thyroid and orbit. The thyrotropin receptor (TSHR), expressed at low levels in orbital tissues, is a leading candidate antigen. Recent evidence suggests that another protein, the insulin-like growth factor-I receptor (IGF-IR), is overexpressed in TAO, and antibodies against IGF-IR have been detected in patients with the disease. Furthermore, TSHR and IGF-IR form a physical and functional complex, and signaling initiated at TSHR requires IGF-IR activity. Identification of therapy for this rare disease has proven challenging and currently relies on nonspecific and inadequate agents, thus representing an important unmet need. A recently completed therapeutic trial suggests that inhibiting IGF-IR activity with a monoclonal antibody may be an effective and safe treatment for active TAO.
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Affiliation(s)
- Terry J Smith
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, and Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48105, USA;
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27
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Sayers N, Hanyaloglu AC. Intracellular Follicle-Stimulating Hormone Receptor Trafficking and Signaling. Front Endocrinol (Lausanne) 2018; 9:653. [PMID: 30450081 PMCID: PMC6225286 DOI: 10.3389/fendo.2018.00653] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 10/17/2018] [Indexed: 12/18/2022] Open
Abstract
Models of G protein-coupled receptor (GPCR) signaling have dramatically altered over the past two decades. Indeed, GPCRs such as the follicle-stimulating hormone receptor (FSHR) have contributed to these new emerging models. We now understand that receptor signaling is highly organized at a spatial level, whereby signaling not only occurs from the plasma membrane but distinct intracellular compartments. Recent studies in the role of membrane trafficking and spatial organization of GPCR signaling in regulating gonadotropin hormone receptor activity has identified novel intracellular compartments, which are tightly linked with receptor signaling and reciprocally regulated by the cellular trafficking machinery. Understanding the impact of these cell biological mechanisms to physiology and pathophysiology is emerging for certain GPCRs. However, for FSHR, the potential impact in both health and disease and the therapeutic possibilities of these newly identified systems is currently unknown, but offers the potential to reassess prior strategies, or unveil novel opportunities, in targeting this receptor.
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Follicle-Stimulating Hormone Receptor: Advances and Remaining Challenges. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 338:1-58. [DOI: 10.1016/bs.ircmb.2018.02.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Affiliation(s)
- Aylin C Hanyaloglu
- Institute of Reproductive and Developmental Biology, Dept. Surgery and Cancer, Imperial College London, UK.
| | - Dimitris K Grammatopoulos
- Translational Medicine, Warwick Medical School & Clinical Biochemistry, Coventry and Warwickshire Pathology Service, UK.
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Ranjan R, Dwivedi H, Baidya M, Kumar M, Shukla AK. Novel Structural Insights into GPCR-β-Arrestin Interaction and Signaling. Trends Cell Biol 2017; 27:851-862. [PMID: 28651823 DOI: 10.1016/j.tcb.2017.05.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 05/25/2017] [Accepted: 05/31/2017] [Indexed: 12/21/2022]
Abstract
G protein-coupled receptors (GPCRs) are major signal recognition and transmission units in the plasma membrane. The interaction of activated and phosphorylated GPCRs with the multifunctional adaptor proteins β-arrestins (βarrs) is crucial for regulation of their signaling and functional outcomes. Over the past few years, a range of structural, biochemical, and cellular studies have revealed novel insights into GPCR-βarr interaction and signaling. Some of these findings have come as a surprise and therefore have the potential to significantly refine the conceptual framework of the GPCR-βarr system. Here we discuss these recent advances with particular emphasis on biphasic GPCR-βarr interaction, the formation of GPCR-G-protein-βarr supercomplexes, and receptor-specific conformational signatures in βarrs. We also underline the emerging research areas that are likely to be at the center stage of investigations in the coming years.
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Affiliation(s)
- Ravi Ranjan
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Hemlata Dwivedi
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Mithu Baidya
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Mohit Kumar
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Arun K Shukla
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India.
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Kuwasako K, Kitamura K, Nagata S, Sekiguchi T, Danfeng J, Murakami M, Hattori Y, Kato J. β-arrestins negatively control human adrenomedullin type 1-receptor internalization. Biochem Biophys Res Commun 2017; 487:438-443. [PMID: 28427767 DOI: 10.1016/j.bbrc.2017.04.083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 04/16/2017] [Indexed: 02/08/2023]
Abstract
Adrenomedullin (AM) is a potent hypotensive peptide that exerts a powerful variety of protective effects against multiorgan damage through the AM type 1 receptor (AM1 receptor), which consists of the calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 2 (RAMP2). Two β-arrestin (β-arr) isoforms, β-arr-1 and β-arr-2, play a central role in the agonist-induced internalization of many receptors for receptor resensitization. Notably, β-arr-biased agonists are now being tested in phase II clinical trials, targeting acute pain and acute heart failure. Here, we examined the effects of β-arr-1 and β-arr-2 on human AM1 receptor internalization. We constructed a V5-tagged chimera in which the cytoplasmic C-terminal tail (C-tail) of CLR was replaced with that of the β2-adrenergic receptor (β2-AR), and it was transiently transfected into HEK-293 cells that stably expressed RAMP2. The cell-surface expression and internalization of the wild-type or chimeric receptor were quantified by flow cytometric analysis. The [125I]AM binding and the AM-induced cAMP production of these receptors were also determined. Surprisingly, the coexpression of β-arr-1 or -2 resulted in significant decreases in AM1 receptor internalization without affecting AM binding and signaling prior to receptor internalization. Dominant-negative (DN) β-arr-1 or -2 also significantly decreased AM-induced AM1 receptor internalization. In contrast, the AM-induced internalization of the chimeric AM1 receptor was markedly augmented by the cotransfection of β-arr-1 or -2 and significantly reduced by the coexpression of DN-β-arr-1 or -2. These results were consistent with those seen for β2-AR. Thus, both β-arrs negatively control AM1 receptor internalization, which depends on the C-tail of CLR.
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Affiliation(s)
- Kenji Kuwasako
- Frontier Science Research Center, University of Miyazaki, Miyazaki 889-1692, Japan.
| | - Kazuo Kitamura
- Division of Circulation and Body Fluid Regulation, Faculty of Medicine, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Sayaka Nagata
- Division of Circulation and Body Fluid Regulation, Faculty of Medicine, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Toshio Sekiguchi
- Noto Marine Laboratory, Institute of Nature and Environmental Technology, Division of Marine Environmental Studies, Kanazawa University, Ishikawa 927-0553, Japan
| | - Jiang Danfeng
- Frontier Science Research Center, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Manabu Murakami
- Department of Pharmacology, Hirosaki University, Graduate School of Medicine, Hirosaki 036-8562, Japan
| | - Yuichi Hattori
- Department of Molecular and Medical Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan
| | - Johji Kato
- Frontier Science Research Center, University of Miyazaki, Miyazaki 889-1692, Japan
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