1
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Patel K, Smith NJ. Primary cilia, A-kinase anchoring proteins and constitutive activity at the orphan G protein-coupled receptor GPR161: A tale about a tail. Br J Pharmacol 2024; 181:2182-2196. [PMID: 36772847 DOI: 10.1111/bph.16053] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 12/22/2022] [Accepted: 02/04/2023] [Indexed: 02/12/2023] Open
Abstract
Primary cilia are non-motile antennae-like structures responsible for sensing environmental changes in most mammalian cells. Ciliary signalling is largely mediated by the Sonic Hedgehog (Shh) pathway, which acts as a master regulator of ciliary protein transit and is essential for normal embryonic development. One particularly important player in primary cilia is the orphan G protein-coupled receptor, GPR161. In this review, we introduce GPR161 in the context of Shh signalling and describe the unique features on its C-terminus such as PKA phosphorylation sites and an A-kinase anchoring protein motif, which may influence the function of the receptor, cAMP compartmentalisation and/or trafficking within primary cilia. We discuss the recent putative pairing of GPR161 and spexin-1, highlighting the additional steps needed before GPR161 could be considered 'deorphanised'. Finally, we speculate that the marked constitutive activity and unconventional regulation of GPR161 may indicate that the receptor may not require an endogenous ligand. LINKED ARTICLES: This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.
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Affiliation(s)
- Kinjal Patel
- Orphan Receptor Laboratory, School of Biomedical Sciences, Faculty of Medicine & Health, UNSW Sydney, Kensington, New South Wales, Australia
| | - Nicola J Smith
- Orphan Receptor Laboratory, School of Biomedical Sciences, Faculty of Medicine & Health, UNSW Sydney, Kensington, New South Wales, Australia
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2
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Gopalakrishnan J, Feistel K, Friedrich BM, Grapin‐Botton A, Jurisch‐Yaksi N, Mass E, Mick DU, Müller R, May‐Simera H, Schermer B, Schmidts M, Walentek P, Wachten D. Emerging principles of primary cilia dynamics in controlling tissue organization and function. EMBO J 2023; 42:e113891. [PMID: 37743763 PMCID: PMC10620770 DOI: 10.15252/embj.2023113891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 08/07/2023] [Accepted: 09/08/2023] [Indexed: 09/26/2023] Open
Abstract
Primary cilia project from the surface of most vertebrate cells and are key in sensing extracellular signals and locally transducing this information into a cellular response. Recent findings show that primary cilia are not merely static organelles with a distinct lipid and protein composition. Instead, the function of primary cilia relies on the dynamic composition of molecules within the cilium, the context-dependent sensing and processing of extracellular stimuli, and cycles of assembly and disassembly in a cell- and tissue-specific manner. Thereby, primary cilia dynamically integrate different cellular inputs and control cell fate and function during tissue development. Here, we review the recently emerging concept of primary cilia dynamics in tissue development, organization, remodeling, and function.
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Affiliation(s)
- Jay Gopalakrishnan
- Institute for Human Genetics, Heinrich‐Heine‐UniversitätUniversitätsklinikum DüsseldorfDüsseldorfGermany
| | - Kerstin Feistel
- Department of Zoology, Institute of BiologyUniversity of HohenheimStuttgartGermany
| | | | - Anne Grapin‐Botton
- Cluster of Excellence Physics of Life, TU DresdenDresdenGermany
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at The University Hospital Carl Gustav Carus and Faculty of Medicine of the TU DresdenDresdenGermany
| | - Nathalie Jurisch‐Yaksi
- Department of Clinical and Molecular MedicineNorwegian University of Science and TechnologyTrondheimNorway
| | - Elvira Mass
- Life and Medical Sciences Institute, Developmental Biology of the Immune SystemUniversity of BonnBonnGermany
| | - David U Mick
- Center for Molecular Signaling (PZMS), Center of Human and Molecular Biology (ZHMB)Saarland School of MedicineHomburgGermany
| | - Roman‐Ulrich Müller
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD), Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Helen May‐Simera
- Institute of Molecular PhysiologyJohannes Gutenberg‐UniversityMainzGermany
| | - Bernhard Schermer
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD), Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Miriam Schmidts
- Pediatric Genetics Division, Center for Pediatrics and Adolescent MedicineUniversity Hospital FreiburgFreiburgGermany
- CIBSS‐Centre for Integrative Biological Signalling StudiesUniversity of FreiburgFreiburgGermany
| | - Peter Walentek
- CIBSS‐Centre for Integrative Biological Signalling StudiesUniversity of FreiburgFreiburgGermany
- Renal Division, Internal Medicine IV, Medical CenterUniversity of FreiburgFreiburgGermany
| | - Dagmar Wachten
- Institute of Innate Immunity, Biophysical Imaging, Medical FacultyUniversity of BonnBonnGermany
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3
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Moulistanos A, Nikolaou T, Sismanoglou S, Gkagkavouzis K, Karaiskou N, Antonopoulou E, Triantafyllidis A, Papakostas S. Investigating the role of genetic variation in vgll3 and six6 in the domestication of gilthead seabream ( Sparus aurata Linnaeus) and European seabass ( Dicentrarchus labrax Linnaeus). Ecol Evol 2023; 13:e10727. [PMID: 38020694 PMCID: PMC10654472 DOI: 10.1002/ece3.10727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 10/27/2023] [Accepted: 10/27/2023] [Indexed: 12/01/2023] Open
Abstract
Gene function conservation is crucial in molecular ecology, especially for key traits like growth and maturation in teleost fish. The vgll3 and six6 genes are known to influence age-at-maturity in Atlantic salmon, but their impact on other fish species is poorly understood. Here, we investigated the association of vgll3 and six6 in the domestication of gilthead seabream and European seabass, both undergoing selective breeding for growth-related traits in the Mediterranean. We analysed two different sets of samples using two different genotyping approaches. The first dataset comprised farmed and wild populations from Greece, genotyped for SNPs within the two genes ('gene-level genotyping'). The second dataset examined 300-600 k SNPs located in the chromosomes of the two genes, derived from a meta-analysis of a Pool-Seq experiment involving farmed and wild populations distributed widely across the Mediterranean ('chromosome-level genotyping'). The gene-level analysis revealed a statistically significant allele frequency differences between farmed and wild populations on both genes in each species. This finding was partially supported by the chromosome-level analysis, identifying highly differentiated regions may be involved in the domestication process at varying distances from the candidate genes. Noteworthy genomic features were found, such as a CpG island in gilthead seabream and novel candidate genes in European seabass, warranting further investigation. These findings support a putative role of vgll3 and six6 in the maturation and growth of gilthead seabream and European seabass, emphasizing the need for further research on their conserved function.
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Affiliation(s)
- Aristotelis Moulistanos
- Department of Genetics, Development & Molecular Biology, School of Biology, Faculty of ScienceAristotle University of ThessalonikiThessalonikiGreece
- Genomics and Epigenomics Translational Research (GENeTres)Center for Interdisciplinary Research and Innovation (CIRI‐AUTH), Balkan CenterThessalonikiGreece
| | - Theopisti Nikolaou
- Department of Genetics, Development & Molecular Biology, School of Biology, Faculty of ScienceAristotle University of ThessalonikiThessalonikiGreece
| | - Smaragda Sismanoglou
- Department of Genetics, Development & Molecular Biology, School of Biology, Faculty of ScienceAristotle University of ThessalonikiThessalonikiGreece
| | - Konstantinos Gkagkavouzis
- Department of Genetics, Development & Molecular Biology, School of Biology, Faculty of ScienceAristotle University of ThessalonikiThessalonikiGreece
- Genomics and Epigenomics Translational Research (GENeTres)Center for Interdisciplinary Research and Innovation (CIRI‐AUTH), Balkan CenterThessalonikiGreece
| | - Nikoleta Karaiskou
- Department of Genetics, Development & Molecular Biology, School of Biology, Faculty of ScienceAristotle University of ThessalonikiThessalonikiGreece
- Genomics and Epigenomics Translational Research (GENeTres)Center for Interdisciplinary Research and Innovation (CIRI‐AUTH), Balkan CenterThessalonikiGreece
| | - Efthimia Antonopoulou
- Department of Zoology, School of BiologyAristotle University of ThessalonikiThessalonikiGreece
| | - Alexandros Triantafyllidis
- Department of Genetics, Development & Molecular Biology, School of Biology, Faculty of ScienceAristotle University of ThessalonikiThessalonikiGreece
- Genomics and Epigenomics Translational Research (GENeTres)Center for Interdisciplinary Research and Innovation (CIRI‐AUTH), Balkan CenterThessalonikiGreece
| | - Spiros Papakostas
- Department of Science and TechnologyInternational Hellenic UniversityThessalonikiGreece
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4
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Tschaikner PM, Regele D, Röck R, Salvenmoser W, Meyer D, Bouvier M, Geley S, Stefan E, Aanstad P. Feedback control of the Gpr161-G αs-PKA axis contributes to basal Hedgehog repression in zebrafish. Development 2021; 148:dev.192443. [PMID: 33531430 DOI: 10.1242/dev.192443] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 01/14/2021] [Indexed: 01/26/2023]
Abstract
Hedgehog (Hh) ligands act as morphogens to direct patterning and proliferation during embryonic development. Protein kinase A (PKA) is a central negative regulator of Hh signalling, and in the absence of Hh ligands, PKA activity prevents inappropriate expression of Hh target genes. The orphan G-protein-coupled receptor Gpr161 contributes to the basal Hh repression machinery by activating PKA. Gpr161 acts as an A-kinase-anchoring protein, and is itself phosphorylated by PKA, but the functional significance of PKA phosphorylation of Gpr161 in the context of Hh signalling remains unknown. Here, we show that loss of Gpr161 in zebrafish leads to constitutive activation of medium and low, but not maximal, levels of Hh target gene expression. Furthermore, we find that PKA phosphorylation-deficient forms of Gpr161, which we show directly couple to Gαs, display an increased sensitivity to Shh, resulting in excess high-level Hh signalling. Our results suggest that PKA feedback-mediated phosphorylation of Gpr161 may provide a mechanism for fine-tuning Gpr161 ciliary localisation and PKA activity.
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Affiliation(s)
- Philipp M Tschaikner
- Institute of Molecular Biology and Center for Molecular Biosciences, University of Innsbruck, Innsbruck 6020, Austria.,Institute of Biochemistry and Center for Molecular Biosciences, University of Innsbruck, Innsbruck 6020, Austria
| | - Dominik Regele
- Institute of Molecular Biology and Center for Molecular Biosciences, University of Innsbruck, Innsbruck 6020, Austria
| | - Ruth Röck
- Institute of Biochemistry and Center for Molecular Biosciences, University of Innsbruck, Innsbruck 6020, Austria
| | - Willi Salvenmoser
- Institute of Zoology and Center of Molecular Bioscience Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Dirk Meyer
- Institute of Molecular Biology and Center for Molecular Biosciences, University of Innsbruck, Innsbruck 6020, Austria
| | - Michel Bouvier
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Stephan Geley
- Division of Molecular Pathophysiology, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Eduard Stefan
- Institute of Biochemistry and Center for Molecular Biosciences, University of Innsbruck, Innsbruck 6020, Austria
| | - Pia Aanstad
- Institute of Molecular Biology and Center for Molecular Biosciences, University of Innsbruck, Innsbruck 6020, Austria
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5
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Methods for Studying Endocytotic Pathways of Herpesvirus Encoded G Protein-Coupled Receptors. Molecules 2020; 25:molecules25235710. [PMID: 33287269 PMCID: PMC7730005 DOI: 10.3390/molecules25235710] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 11/20/2020] [Accepted: 12/01/2020] [Indexed: 12/20/2022] Open
Abstract
Endocytosis is a fundamental process involved in trafficking of various extracellular and transmembrane molecules from the cell surface to its interior. This enables cells to communicate and respond to external environments, maintain cellular homeostasis, and transduce signals. G protein-coupled receptors (GPCRs) constitute a family of receptors with seven transmembrane alpha-helical domains (7TM receptors) expressed at the cell surface, where they regulate physiological and pathological cellular processes. Several herpesviruses encode receptors (vGPCRs) which benefits the virus by avoiding host immune surveillance, supporting viral dissemination, and thereby establishing widespread and lifelong infection, processes where receptor signaling and/or endocytosis seem central. vGPCRs are rising as potential drug targets as exemplified by the cytomegalovirus-encoded receptor US28, where its constitutive internalization has been exploited for selective drug delivery in virus infected cells. Therefore, studying GPCR trafficking is of great importance. This review provides an overview of the current knowledge of endocytic and cell localization properties of vGPCRs and methodological approaches used for studying receptor internalization. Using such novel approaches, we show constitutive internalization of the BILF1 receptor from human and porcine γ-1 herpesviruses and present motifs from the eukaryotic linear motif (ELM) resources with importance for vGPCR endocytosis.
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6
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Carta R, Del Baldo G, Miele E, Po A, Besharat ZM, Nazio F, Colafati GS, Piccirilli E, Agolini E, Rinelli M, Lodi M, Cacchione A, Carai A, Boccuto L, Ferretti E, Locatelli F, Mastronuzzi A. Cancer Predisposition Syndromes and Medulloblastoma in the Molecular Era. Front Oncol 2020; 10:566822. [PMID: 33194646 PMCID: PMC7658916 DOI: 10.3389/fonc.2020.566822] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 09/30/2020] [Indexed: 12/14/2022] Open
Abstract
Medulloblastoma is the most common malignant brain tumor in children. In addition to sporadic cases, medulloblastoma may occur in association with cancer predisposition syndromes. This review aims to provide a complete description of inherited cancer syndromes associated with medulloblastoma. We examine their epidemiological, clinical, genetic, and diagnostic features and therapeutic approaches, including their correlation with medulloblastoma. Furthermore, according to the most recent molecular advances, we describe the association between the various molecular subgroups of medulloblastoma and each cancer predisposition syndrome. Knowledge of the aforementioned conditions can guide pediatric oncologists in performing adequate cancer surveillance. This will allow clinicians to promptly diagnose and treat medulloblastoma in syndromic children, forming a team with all specialists necessary for the correct management of the other various manifestations/symptoms related to the inherited cancer syndromes.
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Affiliation(s)
- Roberto Carta
- Department of Hematology/Oncology, Cell and Gene Therapy, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Giada Del Baldo
- Department of Hematology/Oncology, Cell and Gene Therapy, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Evelina Miele
- Department of Hematology/Oncology, Cell and Gene Therapy, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Agnese Po
- Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | | | - Francesca Nazio
- Department of Hematology/Oncology, Cell and Gene Therapy, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Giovanna Stefania Colafati
- Oncological Neuroradiology Unit, Imaging Department, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Eleonora Piccirilli
- Department of Neuroscience, Imaging and Clinical Science, University "G.d'Annunzio" of Chieti, Chieti, Italy
| | - Emanuele Agolini
- Laboratory of Medical Genetics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Martina Rinelli
- Laboratory of Medical Genetics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Mariachiara Lodi
- Department of Hematology/Oncology, Cell and Gene Therapy, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Antonella Cacchione
- Department of Hematology/Oncology, Cell and Gene Therapy, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Andrea Carai
- Neurosurgery Unit, Department of Neurological and Psychiatric Sciences, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - Luigi Boccuto
- JC Self Research Institute, Greenwood Genetic Center, Greenwood, SC, United States.,School of Nursing, College of Behavioral, Social and Health Science, Clemson University, Clemson, SC, United States
| | - Elisabetta Ferretti
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Franco Locatelli
- Department of Hematology/Oncology, Cell and Gene Therapy, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.,Department of Maternal, Infantile, and Urological Sciences, University of Rome La Sapienza, Rome, Italy
| | - Angela Mastronuzzi
- Department of Hematology/Oncology, Cell and Gene Therapy, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
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7
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Wang M, Li P, Wang H, Dong L, Wu C, Zhao Z. Identification and spatiotemporal expression of gpr161 genes in zebrafish. Gene 2020; 730:144303. [PMID: 31884103 DOI: 10.1016/j.gene.2019.144303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/26/2019] [Accepted: 12/18/2019] [Indexed: 11/16/2022]
Abstract
G protein coupled Receptor 161 (GPR161) is a ciliary orphan GPCR. It is reported to play critical roles in regulating vertebrate Hedgehog (Hh) signaling pathway, that is conserved in metazoan and functions in earlier embryogenesis and homeostasis of adult metabolism. However, to date, all GPR161 functional studies were performed only in mouse. Knock out gpr161 in NIH3T3 cell lines, the common material for Hh mechanism research, failed to give any obvious Hh pathway defects, raising the question that whether GPR161 functions in Hh pathway is conserved in vertebrate system. Here, we described the characterization and spatiotemporal expression of two zebrafish gpr161 homologs, gpr161a and gpr161b. gpr161a was renamed of the gpr161 previously identified, while gpr161b was novel identified. The whole-mount in situ hybridization and quantitative PCR results showed that gpr161a is initially expressed in maternal manner while gpr161b is not. Although these two gpr161 showed ubiquitously expressed at early embryonic stages, each of them had tissue specific accumulation. gpr161a is abundant in the central nervous system (CNS) and adaxial cells, where are rich of Hh responding cells. Together gpr161a was highly expressed in muscle and intestine in adult fishes. These results strongly suggest the regulating roles of Gpr161 a in zebrafish Hh signal transduction. gpr161b was also accumulated in the CNS but mainly at the midline in the neural tube, similar pattern as wnt5b expression in such area, suggesting its potential function correlated with WNT signaling pathway. Interestingly, we also found the specific accumulation of gpr161 in posterior blood island (PBI) at 24 hours post fertilization (hpf), indicating the gpr161 may play roles in early hematopoiesis in zebrafish. Our work provides a starting point to unveil the divergent functions of gpr161 in vertebrate and will shed light on the studies of mechanism of Hh and WNT pathways, as well as early hematopoiesis.
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Affiliation(s)
- Min Wang
- Institutes of Biomedical Sciences, 1331 Local Bio-Resources and Health Industry Collaborative Innovation Center of Shanxi Province, Shanxi University, Taiyuan, 030006, China; Chemical Biology and Molecular Engineering Key Laboratory of Ministry of Education, Institute of biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Ping Li
- Institutes of Biomedical Sciences, 1331 Local Bio-Resources and Health Industry Collaborative Innovation Center of Shanxi Province, Shanxi University, Taiyuan, 030006, China
| | - Hao Wang
- Institutes of Biomedical Sciences, 1331 Local Bio-Resources and Health Industry Collaborative Innovation Center of Shanxi Province, Shanxi University, Taiyuan, 030006, China
| | - Lina Dong
- Central Laboratory, Shanxi Provincial People's Hospital, Affiliate of Shanxi Medical University, Taiyuan, Shanxi, 030012, China
| | - Changxin Wu
- Institutes of Biomedical Sciences, 1331 Local Bio-Resources and Health Industry Collaborative Innovation Center of Shanxi Province, Shanxi University, Taiyuan, 030006, China.
| | - Zhonghua Zhao
- Institutes of Biomedical Sciences, 1331 Local Bio-Resources and Health Industry Collaborative Innovation Center of Shanxi Province, Shanxi University, Taiyuan, 030006, China.
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8
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Begemann M, Waszak SM, Robinson GW, Jäger N, Sharma T, Knopp C, Kraft F, Moser O, Mynarek M, Guerrini-Rousseau L, Brugieres L, Varlet P, Pietsch T, Bowers DC, Chintagumpala M, Sahm F, Korbel JO, Rutkowski S, Eggermann T, Gajjar A, Northcott P, Elbracht M, Pfister SM, Kontny U, Kurth I. Germline GPR161 Mutations Predispose to Pediatric Medulloblastoma. J Clin Oncol 2019; 38:43-50. [PMID: 31609649 PMCID: PMC6943973 DOI: 10.1200/jco.19.00577] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
PURPOSE The identification of a heritable tumor predisposition often leads to changes in management and increased surveillance of individuals who are at risk; however, for many rare entities, our knowledge of heritable predisposition is incomplete. METHODS Families with childhood medulloblastoma, one of the most prevalent childhood malignant brain tumors, were investigated to identify predisposing germline mutations. Initial findings were extended to genomes and epigenomes of 1,044 medulloblastoma cases from international multicenter cohorts, including retrospective and prospective clinical studies and patient series. RESULTS We identified heterozygous germline mutations in the G protein-coupled receptor 161 (GPR161) gene in six patients with infant-onset medulloblastoma (median age, 1.5 years). GPR161 mutations were exclusively associated with the sonic hedgehog medulloblastoma (MBSHH) subgroup and accounted for 5% of infant MBSHH cases in our cohorts. Molecular tumor profiling revealed a loss of heterozygosity at GPR161 in all affected MBSHH tumors, atypical somatic copy number landscapes, and no additional somatic driver events. Analysis of 226 MBSHH tumors revealed somatic copy-neutral loss of heterozygosity of chromosome 1q as the hallmark characteristic of GPR161 deficiency and the primary mechanism for biallelic inactivation of GPR161 in affected MBSHH tumors. CONCLUSION Here, we describe a novel brain tumor predisposition syndrome that is caused by germline GPR161 mutations and characterized by MBSHH in infants. Additional studies are needed to identify a potential broader tumor spectrum associated with germline GPR161 mutations.
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Affiliation(s)
| | | | | | - Natalie Jäger
- Hopp Children's Cancer Center Heidelberg, Heidelberg, Germany.,German Cancer Research Centre, Heidelberg, Germany
| | - Tanvi Sharma
- Hopp Children's Cancer Center Heidelberg, Heidelberg, Germany.,German Cancer Research Centre, Heidelberg, Germany
| | | | | | | | - Martin Mynarek
- University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | | | | | | | | | | | - Felix Sahm
- German Cancer Research Centre, Heidelberg, Germany.,University Hospital Heidelberg, Heidelberg, Germany
| | - Jan O Korbel
- European Molecular Biology Laboratory, Heidelberg, Germany
| | | | | | - Amar Gajjar
- St Jude Children's Research Hospital, Memphis, TN
| | | | | | - Stefan M Pfister
- Hopp Children's Cancer Center Heidelberg, Heidelberg, Germany.,German Cancer Research Centre, Heidelberg, Germany.,University Hospital Heidelberg, Heidelberg, Germany
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9
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Trivellin G, Hernández-Ramírez LC, Swan J, Stratakis CA. An orphan G-protein-coupled receptor causes human gigantism and/or acromegaly: Molecular biology and clinical correlations. Best Pract Res Clin Endocrinol Metab 2018; 32:125-140. [PMID: 29678281 DOI: 10.1016/j.beem.2018.02.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
X-linked acrogigantism (X-LAG) is a recently described form of familial or sporadic pituitary gigantism characterized by very early onset GH and IGF-1 excess, accelerated growth velocity, gigantism and/or acromegaloid features. Germline or somatic microduplications of the Xq26.3 chromosomal region, invariably involving the GPR101 gene, constitute the genetic defect leading to X-LAG. GPR101 encodes a class A G protein-coupled receptor that activates the 3',5'-cyclic adenosine monophosphate signaling pathway. Highly expressed in the central nervous system, the main physiological function and ligand of GPR101 remain unknown, but it seems to play a role in the normal development of the GHRH-GH axis. Early recognition of X-LAG cases is imperative because these patients require clinical management that differs from that of other patients with acromegaly or gigantism. Medical treatment with pegvisomant seems to be the best approach, since X-LAG tumors are resistant to the treatment with somatostatin analogues and dopamine agonists; surgical cure requires near-total hypophysectomy. Currently, the efforts of our research focus on the identification of GPR101 ligands; in addition, the long-term follow-up of X-LAG patients is of extreme interest as this is expected to lead to better understanding of GPR101 effects on human pathophysiology.
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Affiliation(s)
- Giampaolo Trivellin
- Section on Endocrinology and Genetics (SEGEN), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, 20892-1862, USA
| | - Laura C Hernández-Ramírez
- Section on Endocrinology and Genetics (SEGEN), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, 20892-1862, USA
| | - Jeremy Swan
- Computer Support Services Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, 20892-1862, USA
| | - Constantine A Stratakis
- Section on Endocrinology and Genetics (SEGEN), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, 20892-1862, USA.
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10
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Cilia have high cAMP levels that are inhibited by Sonic Hedgehog-regulated calcium dynamics. Proc Natl Acad Sci U S A 2016; 113:13069-13074. [PMID: 27799542 DOI: 10.1073/pnas.1602393113] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Protein kinase A (PKA) phosphorylates Gli proteins, acting as a negative regulator of the Hedgehog pathway. PKA was recently detected within the cilium, and PKA activity specifically in cilia regulates Gli processing. Using a cilia-targeted genetically encoded sensor, we found significant basal PKA activity. Using another targeted sensor, we measured basal ciliary cAMP that is fivefold higher than whole-cell cAMP. The elevated basal ciliary cAMP level is a result of adenylyl cyclase 5 and 6 activity that depends on ciliary phosphatidylinositol (3,4,5)-trisphosphate (PIP3), not stimulatory G protein (Gαs), signaling. Sonic Hedgehog (SHH) reduces ciliary cAMP levels, inhibits ciliary PKA activity, and increases Gli1. Remarkably, SHH regulation of ciliary cAMP and downstream signals is not dependent on inhibitory G protein (Gαi/o) signaling but rather Ca2+ entry through a Gd3+-sensitive channel. Therefore, PIP3 sustains high basal cAMP that maintains PKA activity in cilia and Gli repression. SHH activates Gli by inhibiting cAMP through a G protein-independent mechanism that requires extracellular Ca2+ entry.
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11
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Casar Tena T, Burkhalter MD, Philipp M. Left-right asymmetry in the light of TOR: An update on what we know so far. Biol Cell 2015; 107:306-18. [PMID: 25943139 PMCID: PMC4744706 DOI: 10.1111/boc.201400094] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 04/29/2015] [Indexed: 01/06/2023]
Abstract
The internal left‐right (LR) asymmetry is a characteristic that exists throughout the animal kingdom from roundworms over flies and fish to mammals. Cilia, which are antenna‐like structures protruding into the extracellular space, are involved in establishing LR asymmetry during early development. Humans who suffer from dysfunctional cilia often develop conditions such as heterotaxy, where internal organs appear to be placed randomly. As a consequence to this failure in asymmetry development, serious complications such as congenital heart defects (CHD) occur. The mammalian (or mechanistic) target of rapamycin (mTOR) pathway has recently emerged as an important regulator regarding symmetry breaking. The mTOR pathway governs fundamental processes such as protein translation or metabolism. Its activity can be transduced by two complexes, which are called TORC1 and TORC2, respectively. So far, only TORC1 has been implicated with asymmetry development and appears to require very precise regulation. A number of recent papers provided evidence that dysregulated TORC1 results in alterations of motile cilia and asymmetry defects. In here, we give an update on what we know so far of mTORC1 in LR asymmetry development.
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Affiliation(s)
- Teresa Casar Tena
- Institute for Biochemistry and Molecular Biology, Ulm University, Ulm, 89081, Germany
| | - Martin D Burkhalter
- Leibniz Institute for Age Research Fritz Lippmann Institute, Jena, 07745, Germany
| | - Melanie Philipp
- Institute for Biochemistry and Molecular Biology, Ulm University, Ulm, 89081, Germany
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12
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Stockert JA, Devi LA. Advancements in therapeutically targeting orphan GPCRs. Front Pharmacol 2015; 6:100. [PMID: 26005419 PMCID: PMC4424851 DOI: 10.3389/fphar.2015.00100] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 04/21/2015] [Indexed: 11/23/2022] Open
Abstract
G-protein coupled receptors (GPCRs) are popular biological targets for drug discovery and development. To date there are more than 140 orphan GPCRs, i.e., receptors whose endogenous ligands are unknown. Traditionally orphan GPCRs have been difficult to study and the development of therapeutic compounds targeting these receptors has been extremely slow although these GPCRs are considered important targets based on their distribution and behavioral phenotype as revealed by animals lacking the receptor. Recent advances in several methods used to study orphan receptors, including protein crystallography and homology modeling are likely to be useful in the identification of therapeutics targeting these receptors. In the past 13 years, over a dozen different Class A GPCRs have been crystallized; this trend is exciting, since homology modeling of GPCRs has previously been limited by the availability of solved structures. As the number of solved GPCR structures continues to grow so does the number of templates that can be used to generate increasingly accurate models of phylogenetically related orphan GPCRs. The availability of solved structures along with the advances in using multiple templates to build models (in combination with molecular dynamics simulations that reveal structural information not provided by crystallographic data and methods for modeling hard-to-predict flexible loop regions) have improved the quality of GPCR homology models. This, in turn, has improved the success rates of virtual ligand screens that use homology models to identify potential receptor binding compounds. Experimental testing of the predicted hits and validation using traditional GPCR pharmacological approaches can be used to drive ligand-based efforts to probe orphan receptor biology as well as to define the chemotypes and chemical scaffolds important for binding. As a result of these advances, orphan GPCRs are emerging from relative obscurity as a new class of drug targets.
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Affiliation(s)
- Jennifer A Stockert
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY USA
| | - Lakshmi A Devi
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY USA
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13
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Li BI, Matteson PG, Ababon MF, Nato AQ, Lin Y, Nanda V, Matise TC, Millonig JH. The orphan GPCR, Gpr161, regulates the retinoic acid and canonical Wnt pathways during neurulation. Dev Biol 2015; 402:17-31. [PMID: 25753732 DOI: 10.1016/j.ydbio.2015.02.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 02/03/2015] [Accepted: 02/11/2015] [Indexed: 10/23/2022]
Abstract
The vacuolated lens (vl) mouse mutation arose on the C3H/HeSnJ background and results in lethality, neural tube defects (NTDs) and cataracts. The vl phenotypes are due to a deletion/frameshift mutation in the orphan GPCR, Gpr161. A recent study using a null allele demonstrated that Gpr161 functions in primary cilia and represses the Shh pathway. We show the hypomorphic Gpr161(vl) allele does not severely affect the Shh pathway. To identify additional pathways regulated by Gpr161 during neurulation, we took advantage of naturally occurring genetic variation in the mouse. Previously Gpr161(vl-C3H) was crossed to different inbred backgrounds including MOLF/EiJ and the Gpr161(vl) mutant phenotypes were rescued. Five modifiers were mapped (Modvl: Modifier of vl) including Modvl5(MOLF). In this study we demonstrate the Modvl5(MOLF) congenic rescues the Gpr161(vl)-associated lethality and NTDs but not cataracts. Bioinformatics determined the transcription factor, Cdx1, is the only annotated gene within the Modvl5 95% CI co-expressed with Gpr161 during neurulation and not expressed in the eye. Using Cdx1 as an entry point, we identified the retinoid acid (RA) and canonical Wnt pathways as downstream targets of Gpr161. QRT-PCR, ISH and IHC determined that expression of RA and Wnt genes are down-regulated in Gpr161(vl/vl) but rescued by the Modvl5(MOLF) congenic during neurulation. Intraperitoneal RA injection restores expression of canonical Wnt markers and rescues Gpr161(vl/vl) NTDs. These results establish the RA and canonical Wnt as pathways downstream of Gpr161 during neurulation, and suggest that Modvl5(MOLF) bypasses the Gpr161(vl) mutation by restoring the activity of these pathways.
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Affiliation(s)
- Bo I Li
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, United States; Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States.
| | - Paul G Matteson
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, United States; Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Myka F Ababon
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, United States; Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Alejandro Q Nato
- Department of Genetics; Rutgers University, Piscataway, NJ, United States
| | - Yong Lin
- Division of Biometrics, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, United States
| | - Vikas Nanda
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, United States; Department of Biochemistry, Rutgers University, Piscataway, NJ, United States; Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Tara C Matise
- Department of Genetics; Rutgers University, Piscataway, NJ, United States
| | - James H Millonig
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, United States; Department of Neuroscience and Cell Biology, Rutgers University, Piscataway, NJ, United States; Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States; Department of Genetics; Rutgers University, Piscataway, NJ, United States.
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14
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Foster SR, Roura E, Molenaar P, Thomas WG. G protein-coupled receptors in cardiac biology: old and new receptors. Biophys Rev 2015; 7:77-89. [PMID: 28509979 DOI: 10.1007/s12551-014-0154-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 11/25/2014] [Indexed: 12/21/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are seven-transmembrane-spanning proteins that mediate cellular and physiological responses. They are critical for cardiovascular function and are targeted for the treatment of hypertension and heart failure. Nevertheless, current therapies only target a small fraction of the cardiac GPCR repertoire, indicating that there are many opportunities to investigate unappreciated aspects of heart biology. Here, we offer an update on the contemporary view of GPCRs and the complexities of their signalling, and review the roles of the 'classical' GPCRs in cardiovascular physiology and disease. We then provide insights into other GPCRs that have been less extensively studied in the heart, including orphan, odorant and taste receptors. We contend that these novel cardiac GPCRs contribute to heart function in health and disease and thereby offer exciting opportunities to therapeutically modulate heart function.
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Affiliation(s)
- Simon R Foster
- School of Biomedical Sciences, University of Queensland, St Lucia Campus, 4072, Brisbane, Australia
| | - Eugeni Roura
- School of Biomedical Sciences, University of Queensland, St Lucia Campus, 4072, Brisbane, Australia.,Centre for Nutrition & Food Sciences, Queensland Alliance for Agriculture and Food Innovation, University of Queensland, St Lucia Campus, Brisbane, Australia
| | - Peter Molenaar
- Faculty of Health, School of Biomedical Sciences, Queensland University of Technology, St Lucia Campus, Brisbane, Australia.,School of Medicine, University of Queensland, St Lucia Campus, Brisbane, Australia
| | - Walter G Thomas
- School of Biomedical Sciences, University of Queensland, St Lucia Campus, 4072, Brisbane, Australia.
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15
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Karaca E, Buyukkaya R, Pehlivan D, Charng WL, Yaykasli KO, Bayram Y, Gambin T, Withers M, Atik MM, Arslanoglu I, Bolu S, Erdin S, Buyukkaya A, Yaykasli E, Jhangiani SN, Muzny DM, Gibbs RA, Lupski JR. Whole-exome sequencing identifies homozygous GPR161 mutation in a family with pituitary stalk interruption syndrome. J Clin Endocrinol Metab 2015; 100:E140-7. [PMID: 25322266 PMCID: PMC4283017 DOI: 10.1210/jc.2014-1984] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
CONTEXT Pituitary stalk interruption syndrome (PSIS) is a rare, congenital anomaly of the pituitary gland characterized by pituitary gland insufficiency, thin or discontinuous pituitary stalk, anterior pituitary hypoplasia, and ectopic positioning of the posterior pituitary gland (neurohypophysis). The clinical presentation of patients with PSIS varies from isolated growth hormone (GH) deficiency to combined pituitary insufficiency and accompanying extrapituitary findings. Mutations in HESX1, LHX4, OTX2, SOX3, and PROKR2 have been associated with PSIS in less than 5% of cases; thus, the underlying genetic etiology for the vast majority of cases remains to be determined. OBJECTIVE We applied whole-exome sequencing (WES) to a consanguineous family with two affected siblings who have pituitary gland insufficiency and radiographic findings of hypoplastic (thin) pituitary gland, empty sella, ectopic neurohypophysis, and interrupted pitiutary stalk-characteristic clinical diagnostic findings of PSIS. DESIGN AND PARTICIPANTS WES was applied to two affected and one unaffected siblings. RESULTS WES of two affected and one unaffected sibling revealed a unique homozygous missense mutation in GPR161, which encodes the orphan G protein-coupled receptor 161, a protein responsible for transducing extracellular signals across the plasma membrane into the cell. CONCLUSION Mutations of GPR161 may be implicated as a potential novel cause of PSIS.
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Affiliation(s)
- Ender Karaca
- Department of Molecular and Human Genetics (E.K., D.P., W.-L.C., Y.B., T.G., M.W., M.M.A., R.A.G., J.R.L.), Baylor College of Medicine, Houston, Texas 77030; Department of Radiology (R.B.), Duzce University Medical School, 81620 Duzce, Turkey; Department of Medical Biology (K.O.Y.), Kahramanmaras Sutcu Imam University, Medical School, 46100 Kahramanmaras, Turkey; Department of Pediatric Endocrinology (I.A., S.B.), Duzce University Medical School, 81620 Duzce, Turkey; Center for Human Genetic Research (S.E.), Massachussetts General Hospital, Boston, Massachussetts 02114; Department of Radiology (A.B.), Duzce Ataturk Community Hospital, 81620 Duzce, Turkey; Department of Medical Biology and Genetics (E.Y.), Duzce University Institute of Health Science, 81620 Duzce, Turkey; Human Genome Sequencing Center (S.N.J., D.M.M., R.A.G.), Baylor College of Medicine, Houston Texas 77030; Department of Pediatrics (J.R.L.), Baylor College of Medicine, Houston, Texas 77030; and Texas Children's Hospital (J.R.L.), Houston, Texas 77030
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16
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Ahmad R, Wojciech S, Jockers R. Hunting for the function of orphan GPCRs - beyond the search for the endogenous ligand. Br J Pharmacol 2014; 172:3212-28. [PMID: 25231237 DOI: 10.1111/bph.12942] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 09/04/2014] [Accepted: 09/09/2014] [Indexed: 12/13/2022] Open
Abstract
Seven transmembrane-spanning proteins (7TM), also called GPCRs, are among the most versatile and evolutionary successful protein families. Out of the 400 non-odourant members identified in the human genome, approximately 100 remain orphans that have not been matched with an endogenous ligand. Apart from the classical deorphanization strategies, several alternative strategies provided recent new insights into the function of these proteins, which hold promise for high therapeutic potential. These alternative strategies consist of the phenotypical characterization of organisms silenced or overexpressing orphan 7TM proteins, the search for constitutive receptor activity and formation of protein complexes including 7TM proteins as well as the development of synthetic, surrogate ligands. Taken together, a variety of ligand-independent functions can be attributed to orphan 7TM proteins that range from constitutive activity to complex formation with other proteins and include 'true' orphans for which no ligand exist and 'conditional' orphans that behave like orphans in the absence of ligand and as non-orphans in the presence of ligand.
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Affiliation(s)
- Raise Ahmad
- Institut Cochin, INSERM, Paris, France.,CNRS UMR 8104, Paris, France.,Paris Descartes University, Paris, France
| | - Stefanie Wojciech
- Institut Cochin, INSERM, Paris, France.,CNRS UMR 8104, Paris, France.,Paris Descartes University, Paris, France
| | - Ralf Jockers
- Institut Cochin, INSERM, Paris, France.,CNRS UMR 8104, Paris, France.,Paris Descartes University, Paris, France
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17
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Hwang SH, Mukhopadhyay S. G-protein-coupled receptors and localized signaling in the primary cilium during ventral neural tube patterning. ACTA ACUST UNITED AC 2014; 103:12-9. [PMID: 24917297 DOI: 10.1002/bdra.23267] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Revised: 05/06/2014] [Accepted: 05/19/2014] [Indexed: 01/04/2023]
Abstract
The primary cilium is critical in sonic hedgehog (Shh)-dependent ventral patterning of the vertebrate neural tube. Most mutants that cause disruption of the cilium result in decreased Shh signaling in the neural tube. In contrast, mutations in the intraflagellar complex A (IFT-A) and the tubby family protein, Tulp3, result in increased Shh signaling in the neural tube. Proteomic analysis of Tulp3-binding proteins first pointed to the role of the IFT-A complex in trafficking Tulp3 into the cilia. Tulp3 directs trafficking of rhodopsin family G-protein-coupled receptors (GPCRs) to the cilia, suggesting the role of a GPCR in mediating the paradoxical effects of the Tulp3/IFT-A complex in causing increased Shh signaling. Gpr161 has recently been identified as a Tulp3/IFT-A-regulated GPCR that localizes to the primary cilium. A null knock-out mouse model of Gpr161 phenocopies Tulp3 and IFT-A mutants, and causes increased Shh signaling throughout the neural tube. In the absence of Shh, the bifunctional Gli transcription factors are proteolytically processed into repressor forms in a protein kinase A (PKA) -dependent and cilium-dependent manner. Gpr161 activity results in increased cAMP levels in a Gαs -coupled manner, and determines processing of Gli3. Shh signaling also results in removal of Gpr161 from the cilia, suggesting that Gpr161 functions in a positive feedback loop in the Shh pathway. As PKA-null and Gαs mutant embryos also exhibit increased Shh signaling in the neural tube, Gpr161 is a strong candidate for a GPCR that regulates ciliary cAMP levels, and activates PKA in close proximity to the cilia.
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Affiliation(s)
- Sun-Hee Hwang
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas
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18
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deCarvalho TN, Subedi A, Rock J, Harfe BD, Thisse C, Thisse B, Halpern ME, Hong E. Neurotransmitter map of the asymmetric dorsal habenular nuclei of zebrafish. Genesis 2014; 52:636-55. [PMID: 24753112 DOI: 10.1002/dvg.22785] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 04/16/2014] [Accepted: 04/18/2014] [Indexed: 12/11/2022]
Abstract
The role of the habenular nuclei in modulating fear and reward pathways has sparked a renewed interest in this conserved forebrain region. The bilaterally paired habenular nuclei, each consisting of a medial/dorsal and lateral/ventral nucleus, can be further divided into discrete subdomains whose neuronal populations, precise connectivity, and specific functions are not well understood. An added complexity is that the left and right habenulae show pronounced morphological differences in many non-mammalian species. Notably, the dorsal habenulae of larval zebrafish provide a vertebrate genetic model to probe the development and functional significance of brain asymmetry. Previous reports have described a number of genes that are expressed in the zebrafish habenulae, either in bilaterally symmetric patterns or more extensively on one side of the brain than the other. The goal of our study was to generate a comprehensive map of the zebrafish dorsal habenular nuclei, by delineating the relationship between gene expression domains, comparing the extent of left-right asymmetry at larval and adult stages, and identifying potentially functional subnuclear regions as defined by neurotransmitter phenotype. Although many aspects of habenular organization appear conserved with rodents, the zebrafish habenulae also possess unique properties that may underlie lateralization of their functions.
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Affiliation(s)
- Tagide N deCarvalho
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland
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19
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G-protein-coupled receptor GPR161 is overexpressed in breast cancer and is a promoter of cell proliferation and invasion. Proc Natl Acad Sci U S A 2014; 111:4191-6. [PMID: 24599592 DOI: 10.1073/pnas.1320239111] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Triple-negative breast cancer (TNBC) accounts for 20% of breast cancer in women and lacks an effective targeted therapy. Therefore, finding common vulnerabilities in these tumors represents an opportunity for more effective treatment. Despite the growing appreciation of G-protein-coupled receptor (GPCR)-mediated signaling in cancer pathogenesis, very little is known about the role GPCRs play in TNBC. Using genomic information of human breast cancer, we have discovered that the orphan GPCR, G-protein-coupled receptor 161 (GPR161) is overexpressed specifically in TNBC and correlates with poor prognosis. Knockdown of GPR161 impairs proliferation of human basal breast cancer cell lines. Overexpression of GPR161 in human mammary epithelial cells increases cell proliferation, migration, intracellular accumulation of E-cadherin, and formation of multiacinar structures in 3D culture. GPR161 forms a signaling complex with the scaffold proteins β-arrestin 2 and Ile Gln motif containing GTPase Activating Protein 1, a regulator of mammalian target of rapamycin complex 1 and E-cadherin. Consistently, GPR161 amplified breast tumors and cells overexpressing GPR161 activate mammalian target of rapamycin signaling and decrease Ile Gln motif containing GTPase Activating Protein 1 phosphorylation. Thus, we identify the orphan GPCR, GPR161, as an important regulator and a potential drug target for TNBC.
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20
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Mukhopadhyay S, Wen X, Ratti N, Loktev A, Rangell L, Scales SJ, Jackson PK. The ciliary G-protein-coupled receptor Gpr161 negatively regulates the Sonic hedgehog pathway via cAMP signaling. Cell 2013; 152:210-23. [PMID: 23332756 DOI: 10.1016/j.cell.2012.12.026] [Citation(s) in RCA: 341] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 10/23/2012] [Accepted: 12/18/2012] [Indexed: 11/25/2022]
Abstract
The primary cilium is required for Sonic hedgehog (Shh) signaling in vertebrates. In contrast to mutants affecting ciliary assembly, mutations in the intraflagellar transport complex A (IFT-A) paradoxically cause increased Shh signaling. We previously showed that the IFT-A complex, in addition to its canonical role in retrograde IFT, binds to the tubby-like protein, Tulp3, and recruits it to cilia. Here, we describe a conserved vertebrate G-protein-coupled receptor, Gpr161, which localizes to primary cilia in a Tulp3/IFT-A-dependent manner. Complete loss of Gpr161 in mouse causes midgestation lethality and increased Shh signaling in the neural tube, phenocopying Tulp3/IFT-A mutants. Constitutive Gpr161 activity increases cAMP levels and represses Shh signaling by determining the processing of Gli3 to its repressor form. Conversely, Shh signaling directs Gpr161 to be internalized from cilia, preventing its activity. Thus, Gpr161 defines a morphogenetic pathway coupling protein kinase A activation to Shh signaling during neural tube development.
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Affiliation(s)
- Saikat Mukhopadhyay
- Department of Research Oncology, Genentech Inc., South San Francisco, CA 94080, USA.
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21
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Xavier-Neto J, Trueba SS, Stolfi A, Souza HM, Sobreira TJP, Schubert M, Castillo HA. An unauthorized biography of the second heart field and a pioneer/scaffold model for cardiac development. Curr Top Dev Biol 2012; 100:67-105. [PMID: 22449841 DOI: 10.1016/b978-0-12-387786-4.00003-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
The identification of subpharyngeal cardiac precursors has had a strong influence on the way we think about early cardiac development. From this discovery was born the concept of multiple heart fields. Early support for the concept came from gene expression, genetic retrospective fate mapping, and gene targeting studies, which collectively suggested the existence of a second heart field (SHF) on the basis of specific Islet-1 (Isl-1) expression, presence of two cardiac ancestral lineages, and compatible cardiac knockout phenotypes, respectively. A decade after the original studies, support for the SHF concept is dwindling. This is because in all bilaterian models studied, Isl expression in heart progenitors is not SHF-specific, because lineage data are best explained by alternative models including an older, truly ancestral, lineage of cardiac pioneers with unrestricted contribution to all cardiac segments and, finally, because the inflow-to-outflow segmental nature of the early vertebrate peristaltic heart has been reaffirmed with novel, less invasive, methodologies. Altogether, the paradigms derived from the discovery of subpharyngeal cardiac progenitors helped us shift from relatively simple models, which rely predominantly either on patterning, gene expression patterns or lineages, to a much more sophisticated body of knowledge in which all these parameters must be accounted. Thus, it is well possible that due consideration of the key elements contained in the inflow/outflow, pioneer/scaffold, ballooning, and SHF hypotheses may provide us with a unified framework of the early stages of cardiac development. Here, we advance into this direction by suggesting an intuitive model of early heart development based on the concept of an inflow/outflow scaffold erected by cardiac pioneers, one that is required to assemble all the subsequent cell contribution that emigrates from cardiac progenitor areas.
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Affiliation(s)
- José Xavier-Neto
- Brazilian National Laboratory for Biosciences, Brazilian Association for Synchrotron Light Technology, Rua Giuseppe Máximo Scolfaro, Campinas, São Paulo, Brazil
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22
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Identification and developmental expression of leucine-rich repeat-containing G protein-coupled receptor 6 (lgr6) in the medaka fish, Oryzias latipes. Dev Genes Evol 2012; 222:217-27. [PMID: 22576653 DOI: 10.1007/s00427-012-0403-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 04/25/2012] [Indexed: 10/28/2022]
Abstract
G protein-coupled receptors are critical regulators of diverse developmental processes such as oocyte maturation, fertilization, gastrulation, and organogenesis. To further study the molecular mechanisms underlying these processes, we cloned and characterized the orphan leucine-rich repeat-containing G protein-coupled receptor 6 (LGR6), a stem cell marker in mammalian hair follicles, in medaka fish, Oryzias latipes. To examine the expression pattern of lgr6, we performed whole-mount in situ hybridization (WISH) during embryogenesis. The expression of lgr6 was first detected as a band in the anterior part of the posterior brain vesicle in 0.5-1 day post fertilization (dpf) embryos. This band disappeared by 2 dpf, but new signals appeared in the otic vesicles bordering the original band and also detected in the nasal placode and posterior lateral line primordia. At later stages (3-5 dpf), lgr6 was widely expressed in the brain, otic vesicle, neuromasts, root of the pectoral fin, cranial cartilage, and gut. Then, we conducted more detailed expression analysis of lgr6 in adult gut using WISH and immunohistochemical staining. Lgr6-positive cells were detected in the crypt-like proliferative zone and in parts of the villus. We also performed RT-PCR of mRNAs from different tissues. The lgr6 mRNA was found highest in the kidney and gill. The transcript was also present in the brain, heart, liver, spleen, intestine, skeletal muscle, testis, and ovary, similar to that of mammalian LGR6. These results suggest that medaka lgr6 plays an important role in organ development during embryogenesis and serves as a good molecular marker for future studies of postembryonic organ-specific development in mammals.
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23
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24
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Orphan 7TM receptors. Br J Pharmacol 2009. [DOI: 10.1111/j.1476-5381.2009.00501_2.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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25
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Bakkers J, Verhoeven MC, Abdelilah-Seyfried S. Shaping the zebrafish heart: from left-right axis specification to epithelial tissue morphogenesis. Dev Biol 2009; 330:213-20. [PMID: 19371733 DOI: 10.1016/j.ydbio.2009.04.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 04/07/2009] [Accepted: 04/07/2009] [Indexed: 11/18/2022]
Abstract
Although vertebrates appear bilaterally symmetric on the outside, various internal organs, including the heart, are asymmetric with respect to their position and/or their orientation based on the left/right (L/R) axis. The L/R axis is determined during embryo development. Determination of the L/R axis is fundamentally different from the determination of the anterior-posterior or the dorsal-ventral axis. In all vertebrates a ciliated organ has been described that induces a left-sided gene expression program, which includes Nodal expression in the left lateral plate mesoderm. To have a better understanding of organ laterality it is important to understand how L/R patterning induces cellular responses during organogenesis. In this review, we discuss the current understanding of the mechanisms of L/R patterning during zebrafish development and focus on how this affects cardiac morphogenesis. Several recent studies have provided unprecedented insights into the intimate link between L/R signaling and the cellular responses that drive morphogenesis of this organ.
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Affiliation(s)
- Jeroen Bakkers
- Hubrecht Institute and University Medical Centre Utrecht, 3584 CT, Utrecht, The Netherlands.
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