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Choi SH, Byambaragchaa M, Kim DJ, Lee JH, Kang MH, Min KS. Specific Signal Transduction of Constitutively Activating (D576G) and Inactivating (R476H) Mutants of Agonist-Stimulated Luteinizing Hormone Receptor in Eel. Int J Mol Sci 2023; 24:ijms24119133. [PMID: 37298083 DOI: 10.3390/ijms24119133] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/02/2023] [Accepted: 05/20/2023] [Indexed: 06/12/2023] Open
Abstract
We investigated the mechanism of signal transduction using inactivating (R476H) and activating (D576G) mutants of luteinizing hormone receptor (LHR) of eel at the conserved regions of intracellular loops II and III, respectively, naturally occurring in mammalian LHR. The expression of D576G and R476H mutants was approximately 58% and 59%, respectively, on the cell surface compared to those of eel LHR-wild type (wt). In eel LHR-wt, cAMP production increased upon agonist stimulation. Cells expressing eel LHR-D576G, a highly conserved aspartic acid residue, exhibited a 5.8-fold increase in basal cAMP response; however, the maximal cAMP response by high-agonist stimulation was approximately 0.62-fold. Mutation of a highly conserved arginine residue in the second intracellular loop of eel LHR (LHR-R476H) completely impaired the cAMP response. The rate of loss in cell-surface expression of eel LHR-wt and D576G mutant was similar to the agonist recombinant (rec)-eel LH after 30 min. However, the mutants presented rates of loss higher than eel LHR-wt did upon rec-eCG treatment. Therefore, the activating mutant constitutively induced cAMP signaling. The inactivating mutation resulted in the loss of LHR expression on the cell surface and no cAMP signaling. These data provide valuable information regarding the structure-function relationship of LHR-LH complexes.
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Affiliation(s)
- Seung-Hee Choi
- Animal BioScience, School of Animal Life Convergence, Hankyong National University, Ansung 17579, Republic of Korea
| | - Munkhzaya Byambaragchaa
- Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Republic of Korea
| | - Dae-Jung Kim
- Aquaculture Industry Division, South Sea Fisheries Research Institute, National Institute of Fisheries Science (NIFS), Yeosu 59780, Republic of Korea
| | - Jong-Hyuk Lee
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Myung-Hwa Kang
- Department of Food Science and Nutrition, Hoseo University, Asan 31499, Republic of Korea
| | - Kwan-Sik Min
- Animal BioScience, School of Animal Life Convergence, Hankyong National University, Ansung 17579, Republic of Korea
- Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Republic of Korea
- Carbon-Neutral Resources Research Center, Hankyong National University, Ansung 17579, Republic of Korea
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The N-Linked Glycosylation Site N191 Is Necessary for PKA Signal Transduction in Eel Follicle-Stimulating Hormone Receptor. Int J Mol Sci 2022; 23:ijms232112792. [PMID: 36361582 PMCID: PMC9655291 DOI: 10.3390/ijms232112792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 10/20/2022] [Accepted: 10/21/2022] [Indexed: 11/24/2022] Open
Abstract
The follicle-stimulating hormone receptor (FSHR) contains several N-linked glycosylation sites in its extracellular region. We conducted the present study to determine whether conserved glycosylated sites in eel FSHR are necessary for cyclic adenosine monophosphate (cAMP) signal transduction. We used site-directed mutagenesis to induce four mutations (N120Q, N191Q, N272Q, and N288Q) in the N-linked glycosylation sites of eel FSHR. In the eel FSHR wild-type (wt), the cAMP response was gradually increased in a dose-dependent manner (0.01–1500 ng/mL), displaying a high response (approximately 57.5 nM/104 cells) at the Rmax level. Three mutants (N120Q, N272Q, and N288Q) showed a considerably decreased signal transduction as a result of high-ligand treatment, whereas one mutant (N191Q) exhibited a completely impaired signal transduction. The expression level of the N191Q mutant was only 9.2% relative to that of the eel FSHR-wt, indicating a negligible expression level. The expression levels of the N120Q and N272Q mutants were approximately 35.9% and 24% of the FSHG-wt, respectively. The N288Q mutant had an expression level similar to that of the eel FSHR-wt, despite the mostly impaired cAMP responsiveness. The loss of the cell surface agonist-receptor complexes was very rapid in the cells expressing eel FSHR-wt and FSHR-N288Q mutants. Specifically, the N191Q mutant was completely impaired by the loss of cell surface receptors, despite treatment with a high concentration of the agonist. Therefore, we suggest that the N191 site is necessary for cAMP signal transduction. This finding implies that the cAMP response, mediated by G proteins, is directly related to the loss of cell surface receptors as a result of high-agonist treatment.
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Goolam MA, Brown AP, Edwards KT, Gregory KJ, Leach K, Conigrave AD. Cell Surface Calcium-Sensing Receptor Heterodimers: Mutant Gene Dosage Affects Ca 2+ Sensing but Not G Protein Interaction. J Bone Miner Res 2022; 37:1787-1807. [PMID: 35848051 PMCID: PMC9545990 DOI: 10.1002/jbmr.4651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 06/20/2022] [Accepted: 07/14/2022] [Indexed: 11/20/2022]
Abstract
The calcium-sensing receptor is a homodimeric class C G protein-coupled receptor (GPCR) that senses extracellular Ca2+ (Ca2+ o ) via a dimeric extracellular Venus flytrap (VFT) unit that activates G protein-dependent signaling via twin Cysteine-rich domains linked to transmembrane heptahelical (HH) bundles. It plays a key role in the regulation of human calcium and thus mineral metabolism. However, the nature of interactions between VFT units and HH bundles, and the impacts of heterozygous or homozygous inactivating mutations, which have implications for disorders of calcium metabolism are not yet clearly defined. Herein we generated CaSR-GABAB1 and CaSR-GABAB2 chimeras subject to GABAB -dependent endoplasmic reticulum sorting to traffic mutant heterodimers to the cell surface. Transfected HEK-293 cells were assessed for Ca2+ o -stimulated Ca2+ i mobilization using mutations in either the VFT domains and/or HH bundle intraloop-2 or intraloop-3. When the same mutation was present in both VFT domains of receptor dimers, analogous to homozygous neonatal severe hyperparathyroidism (NSHPT), receptor function was markedly impaired. Mutant heterodimers containing one wild-type (WT) and one mutant VFT domain, however, corresponding to heterozygous familial hypocalciuric hypercalcemia type-1 (FHH-1), supported maximal signaling with reduced Ca2+ o potency. Thus two WT VFT domains were required for normal Ca2+ o potency and there was a pronounced gene-dosage effect. In contrast, a single WT HH bundle was insufficient for maximal signaling and there was no functional difference between heterodimers in which the mutation was present in one or both intraloops; ie, no gene-dosage effect. Finally, we observed that the Ca2+ o -stimulated CaSR operated exclusively via signaling in-trans and not via combined in-trans and in-cis signaling. We consider how receptor asymmetry may support the underlying mechanisms. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Mahvash A Goolam
- School of Life and Environmental Sciences, Charles Perkins Centre (D17), University of Sydney, NSW, Australia
| | - Alice P Brown
- School of Life and Environmental Sciences, Charles Perkins Centre (D17), University of Sydney, NSW, Australia
| | - Kimberly T Edwards
- School of Life and Environmental Sciences, Charles Perkins Centre (D17), University of Sydney, NSW, Australia
| | - Karen J Gregory
- Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia
| | - Katie Leach
- Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia
| | - Arthur D Conigrave
- School of Life and Environmental Sciences, Charles Perkins Centre (D17), University of Sydney, NSW, Australia
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Bakshi T, Pham D, Kaur R, Sun B. Hidden Relationships between N-Glycosylation and Disulfide Bonds in Individual Proteins. Int J Mol Sci 2022; 23:ijms23073742. [PMID: 35409101 PMCID: PMC8998389 DOI: 10.3390/ijms23073742] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 03/25/2022] [Accepted: 03/28/2022] [Indexed: 02/04/2023] Open
Abstract
N-Glycosylation (NG) and disulfide bonds (DBs) are two prevalent co/post-translational modifications (PTMs) that are often conserved and coexist in membrane and secreted proteins involved in a large number of diseases. Both in the past and in recent times, the enzymes and chaperones regulating these PTMs have been constantly discovered to directly interact with each other or colocalize in the ER. However, beyond a few model proteins, how such cooperation affects N-glycan modification and disulfide bonding at selective sites in individual proteins is largely unknown. Here, we reviewed the literature to discover the current status in understanding the relationships between NG and DBs in individual proteins. Our results showed that more than 2700 human proteins carry both PTMs, and fewer than 2% of them have been investigated in the associations between NG and DBs. We summarized both these proteins with the reported relationships in the two PTMs and the tools used to discover the relationships. We hope that, by exposing this largely understudied field, more investigations can be encouraged to unveil the hidden relationships of NG and DBs in the majority of membranes and secreted proteins for pathophysiological understanding and biotherapeutic development.
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Affiliation(s)
- Tania Bakshi
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada;
| | - David Pham
- Department of Computing Science, Simon Fraser University, Burnaby, BC V5A 1S6, Canada;
| | - Raminderjeet Kaur
- Faculty of Health Science, Simon Fraser University, Burnaby, BC V5A 1S6, Canada;
| | - Bingyun Sun
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada;
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
- Correspondence:
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Shi M, Wang W, Zhang J, Li B, Lv D, Wang D, Wang S, Cheng D, Ma T. Identification of RET fusions in a Chinese multicancer retrospective analysis by next-generation sequencing. Cancer Sci 2021; 113:308-318. [PMID: 34710947 PMCID: PMC8748217 DOI: 10.1111/cas.15181] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 09/22/2021] [Accepted: 10/24/2021] [Indexed: 12/19/2022] Open
Abstract
Fusion of RET with different partner genes has been detected in papillary thyroid, lung, colorectal, pancreatic, and breast cancer. Approval of selpercatinib for treatment of lung and thyroid cancer with RET gene mutations or fusions calls for studies to explore RET fusion partners and their eligibility for RET‐based targeted therapy. In this study, RET fusion patterns in a large group of Chinese cancer patients covering several cancer types were identified using next‑generation sequencing. A total of 44 fusion patterns were identified in the study cohort with KIF5B, CCDC6, and ERC1 being the most common RET fusion partners. Notably, 17 novel fusions were first reported in this study. Prevalence of functional RET fusions was 1.05% in lung cancer, 6.03% in thyroid cancer, 0.39% in colorectal cancer, and less than 0.1% in gastric cancer and hepatocellular carcinoma. Analysis showed a preference for fusion partners in different tumor types, with KIF5B being the common type in lung cancer, CCDC6 in thyroid cancer, and NCOA4 in colorectal cancer. Co‐occurrence of EGFR mutations and RET fusions with rare partner genes (rather than KIF5B) in lung cancer patients was correlated with epidermal growth factor receptor‐tyrosine kinase inhibitor resistance and could predict response to targeted therapies. Findings from this study provide a guide to clinicians in determining tumors with specific fusion patterns as candidates for RET targeted therapies.
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Affiliation(s)
- Minke Shi
- Department of Thoracic and Cardiovascular Surgery, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China
| | - Weiran Wang
- Department of Translational Medicine, Genetron Health (Beijing) Technology, Co. Ltd., Beijing, China
| | - Jinku Zhang
- Department of Pathology, Key Laboratory of Molecular Pathology and Early Diagnosis of Tumor in Hebei Province, The First Centre Hospital of Baoding, Baoding, China
| | - Bobo Li
- Department of Thoracic Surgery, Shandong Cancer Hospital Affiliated to Shandong University, Jinan, China
| | - Dongxiao Lv
- Tumor Research and Therapy Center, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Danhua Wang
- Department of Translational Medicine, Genetron Health (Beijing) Technology, Co. Ltd., Beijing, China
| | - Sizhen Wang
- Genetron Health (Beijing) Technology, Co. Ltd., Beijing, China
| | - Dezhi Cheng
- Department of Thoracic Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Tonghui Ma
- Department of Translational Medicine, Genetron Health (Beijing) Technology, Co. Ltd., Beijing, China
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Byambaragchaa M, Seong HK, Choi SH, Kim DJ, Kang MH, Min KS. Constitutively Activating Mutants of Equine LH/CGR Constitutively Induce Signal Transduction and Inactivating Mutations Impair Biological Activity and Cell-Surface Receptor Loss In Vitro. Int J Mol Sci 2021; 22:ijms221910723. [PMID: 34639064 PMCID: PMC8509413 DOI: 10.3390/ijms221910723] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 12/26/2022] Open
Abstract
The signal transduction of the equine lutropin/choriogonadotropin receptor (eLH/CGR) is unclear in naturally occurring activating/inactivating mutants of this receptor, which plays an important role in reproductive physiology. We undertook the present study to determine whether conserved structurally related mutations in eLH/CGR exhibit similar mechanisms of signal transduction. We constructed four constitutively activating mutants (M398T, L457R, D564G, and D578Y) and three inactivating mutants (D405N, R464H, and Y546F); measured cyclic adenosine monophosphate (cAMP) accumulation via homogeneous time-resolved fluorescence assays in Chinese hamster ovary cells; and investigated cell-surface receptor loss using an enzyme-linked immunosorbent assay in human embryonic kidney 293 cells. The eLH/CGR-L457R-, -D564G-, and -D578Y-expressing cells exhibited 16.9-, 16.4-, and 11.2-fold increases in basal cAMP response, respectively. The eLH/CGR-D405N- and R464H-expressing cells presented a completely impaired signal transduction, whereas the Y546F-expressing cells exhibited a small increase in cAMP response. The cell-surface receptor loss was 1.4- to 2.4-fold greater in the activating-mutant-expressing cells than in wild-type eLH/CGR-expressing cells, but was completely impaired in the D405N- and Y546F-expressing cells, despite treatment with a high concentration of agonist. In summary, the state of activation of eLH/CGR influenced agonist-induced cell-surface receptor loss, which was directly related to the signal transduction of constitutively activating mutants.
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Affiliation(s)
- Munkhzaya Byambaragchaa
- Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea; (M.B.); (H.-K.S.)
| | - Hoon-Ki Seong
- Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea; (M.B.); (H.-K.S.)
| | - Seung-Hee Choi
- Animal Biotechnology, Graduate School of Future Convergence Technology, Hankyong National University, Ansung 17579, Korea;
| | - Dae-Jung Kim
- Jeju Fisheries Research Institute, National Institute of Fisheries Science (NIFS), Jeju 63610, Korea;
| | - Myung-Hwa Kang
- Department of Food Science and Nutrition, Hoseo University, Asan 31499, Korea;
| | - Kwan-Sik Min
- Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea; (M.B.); (H.-K.S.)
- Animal Biotechnology, Graduate School of Future Convergence Technology, Hankyong National University, Ansung 17579, Korea;
- Correspondence: ; Tel.: +82-31-670-5421; Fax: +82-31-670-5417
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Okamoto Y, Shikano S. Tyrosine sulfation and O-glycosylation of chemoattractant receptor GPR15 differentially regulate interaction with GPR15L. J Cell Sci 2021; 134:237784. [PMID: 33758080 DOI: 10.1242/jcs.247833] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 03/15/2021] [Indexed: 12/23/2022] Open
Abstract
GPR15 is a G-protein-coupled receptor (GPCR) that directs lymphocyte homing to the colon and skin. Recent studies have identified a chemokine-like protein GPR15L (also known as C10orf99) as a functional ligand of GPR15. In this study, we examined the structural elements that regulate the GPR15-GPR15L interaction with primary focus on post-translational modifications (PTMs) of receptor N-terminus and on the C-terminus of the ligand. Our findings reveal that the GPR15 receptor is sulfated on the N-terminal tyrosine residue(s) and disruption of tyrosine sulfation inhibits binding of GPR15L. In contrast, the disruption of O-glycosylation on the N-terminal threonine or serine residues, or the removal of α2,3-linked sialic acids from O-glycans, enhances the GPR15L binding. Thus, GPR15 represents a unique chemoattractant receptor in which different N-terminal PTMs regulate its ligand binding in a contrasting manner. We further demonstrate that, unlike canonical chemokines, GPR15L activity critically requires its extreme C-terminal residue and that its hydrophobicity may be a key attribute that facilitates an optimal interaction with the receptor. Our results reveal novel insights into chemoattractant receptor-ligand interaction and provide a valid footing for potential intervention targeting the GPR15-GPR15L axis.
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Affiliation(s)
- Yukari Okamoto
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607-7170, USA
| | - Sojin Shikano
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607-7170, USA
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Ellaithy A, Gonzalez-Maeso J, Logothetis DA, Levitz J. Structural and Biophysical Mechanisms of Class C G Protein-Coupled Receptor Function. Trends Biochem Sci 2020; 45:1049-1064. [PMID: 32861513 PMCID: PMC7642020 DOI: 10.1016/j.tibs.2020.07.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/22/2020] [Accepted: 07/30/2020] [Indexed: 02/07/2023]
Abstract
Groundbreaking structural and spectroscopic studies of class A G protein-coupled receptors (GPCRs), such as rhodopsin and the β2 adrenergic receptor, have provided a picture of how structural rearrangements between transmembrane helices control ligand binding, receptor activation, and effector coupling. However, the activation mechanism of other GPCR classes remains more elusive, in large part due to complexity in their domain assembly and quaternary structure. In this review, we focus on the class C GPCRs, which include metabotropic glutamate receptors (mGluRs) and gamma-aminobutyric acid B (GABAB) receptors (GABABRs) most prominently. We discuss the unique biophysical questions raised by the presence of large extracellular ligand-binding domains (LBDs) and constitutive homo/heterodimerization. Furthermore, we discuss how recent studies have begun to unravel how these fundamental class C GPCR features impact the processes of ligand binding, receptor activation, signal transduction, regulation by accessory proteins, and crosstalk with other GPCRs.
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Affiliation(s)
- Amr Ellaithy
- Department of Neurology, University of Iowa, Iowa City, IA 52242, USA; Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Javier Gonzalez-Maeso
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
| | - Diomedes A Logothetis
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, USA; Department of Chemistry and Chemical Biology, College of Science and Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA
| | - Joshua Levitz
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA.
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Møller TC, Pedersen MF, van Senten JR, Seiersen SD, Mathiesen JM, Bouvier M, Bräuner-Osborne H. Dissecting the roles of GRK2 and GRK3 in μ-opioid receptor internalization and β-arrestin2 recruitment using CRISPR/Cas9-edited HEK293 cells. Sci Rep 2020; 10:17395. [PMID: 33060647 PMCID: PMC7567791 DOI: 10.1038/s41598-020-73674-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 09/18/2020] [Indexed: 01/14/2023] Open
Abstract
Most G protein-coupled receptors (GPCRs) recruit β-arrestins and internalize upon agonist stimulation. For the μ-opioid receptor (μ-OR), this process has been linked to development of opioid tolerance. GPCR kinases (GRKs), particularly GRK2 and GRK3, have been shown to be important for μ-OR recruitment of β-arrestin and internalization. However, the contribution of GRK2 and GRK3 to β-arrestin recruitment and receptor internalization, remain to be determined in their complete absence. Using CRISPR/Cas9-mediated genome editing we established HEK293 cells with knockout of GRK2, GRK3 or both to dissect their individual contributions in β-arrestin2 recruitment and μ-OR internalization upon stimulation with four different agonists. We showed that GRK2/3 removal reduced agonist-induced μ-OR internalization and β-arrestin2 recruitment substantially and we found GRK2 to be more important for these processes than GRK3. Furthermore, we observed a sustained and GRK2/3 independent component of β-arrestin2 recruitment to the plasma membrane upon μ-OR activation. Rescue expression experiments restored GRK2/3 functions. Inhibition of GRK2/3 using the small molecule inhibitor CMPD101 showed a high similarity between the genetic and pharmacological approaches, cross-validating the specificity of both. However, off-target effects were observed at high CMPD101 concentrations. These GRK2/3 KO cell lines should prove useful for a wide range of studies on GPCR function.
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Affiliation(s)
- Thor C Møller
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100, Copenhagen, Denmark.
| | - Mie F Pedersen
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Jeffrey R van Senten
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Sofie D Seiersen
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Jesper M Mathiesen
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Michel Bouvier
- Department of Biochemistry and Molecular Medicine, Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC, Canada
| | - Hans Bräuner-Osborne
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100, Copenhagen, Denmark.
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Constitutive Activation and Inactivation of Mutations Inducing Cell Surface Loss of Receptor and Impairing of Signal Transduction of Agonist-Stimulated Eel Follicle-Stimulating Hormone Receptor. Int J Mol Sci 2020; 21:ijms21197075. [PMID: 32992880 PMCID: PMC7583038 DOI: 10.3390/ijms21197075] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 09/23/2020] [Accepted: 09/23/2020] [Indexed: 12/17/2022] Open
Abstract
In the present study, we investigated the signal transduction of mutants of the eel follicle-stimulating hormone receptor (eelFSHR). Specifically, we examined the constitutively activating mutant D540G in the third intracellular loop, and four inactivating mutants (A193V, N195I, R546C, and A548V). To directly assess functional effects, we conducted site-directed mutagenesis to generate mutant receptors. We measured cyclic adenosine monophosphate (cAMP) accumulation via homogeneous time-resolved fluorescence assays in Chinese hamster ovary (CHO-K1) cells and investigated cell surface receptor loss using an enzyme-linked immunosorbent assay in human embryonic kidney (HEK) 293 cells. The cells expressing eelFSHR-D540G exhibited a 23-fold increase in the basal cAMP response without agonist treatment. The cells expressing A193V, N195I, and A548V mutants had completely impaired signal transduction, whereas those expressing the R546C mutant exhibited little increase in cAMP responsiveness and a small increase in signal transduction. Cell surface receptor loss in the cells expressing inactivating mutants A193V, R546C, and A548V was clearly slower than in the cell expressing the wild-type eelFSHR. However, cell surface receptor loss in the cells expressing inactivating mutant N195I decreased in a similar manner to that of the cells expressing the wild-type eelFSHR or the activating mutant D540G, despite the completely impaired cAMP response. These results provide important information regarding the structure–function relationships of G protein-coupled receptors during signal transduction.
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Boisen IM, Mos I, Lerche-Black EM, Juul A, Bräuner-Osborne H, Blomberg Jensen M. Heterozygous Mutation (Q459R) in the Calcium-Sensing Receptor Gene Causes Familial Hypocalciuric Hypercalcemia 1 (FHH1). J Clin Endocrinol Metab 2020; 105:5628138. [PMID: 32160303 DOI: 10.1210/clinem/dgz205] [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: 09/10/2019] [Accepted: 11/14/2019] [Indexed: 01/08/2023]
Abstract
CONTEXT Several heterozygous loss-of-function mutations in the calcium-sensing receptor gene (CASR) leading to elevated ionized serum calcium and familial hypocalciuric hypercalcemia 1 (FHH1) have been characterized. Few mutations are not pathogenic, and previous studies suggested that the Q459R mutation does not result in an FHH1 phenotype. OBJECTIVE We identified a family with a heterozygous CASR Q459R mutation and characterized their calcium homeostasis and the pathophysiological mechanisms of a homozygous and heterozygous Q459R mutation in vitro. DESIGN The index patient and her family had clinical, biochemical, and genetic analyses performed. In vitro functional characterization of homozygous and heterozygous (Q459R) mutations was conducted by determining CaSR cell-surface expression and inositol monophosphate (IP1) signaling in transiently transfected human embryonic kidney 293A (HEK293A) cells. RESULTS All 3 heterozygous carriers had mild asymptomatic hypercalcemia, hypocalciuria, and 2 had elevated serum parathyroid hormone (PTH). In vitro characterization in HEK293A cells revealed that CASR Q459R is a loss-of-function mutation with no impact on cell-surface expression. Cells with the homozygous Q459R genotype had significantly reduced calcium potency of IP1 signaling compared to wild type, whereas the heterozygous Q459R also had lower calcium potency albeit not significantly different from wild type. CONCLUSION A loss-of-function Q459R mutation in CASR in a family caused FHH1 characterized by elevated ionized calcium and PTH and low calcium excretion. The marked presence of CaSR at the membrane and inhibition of IP1 signaling in vitro suggest that calcimimetics may be functional in patients with this mutation, which seems to be a mild loss-of-function mutation associated with autosomal dominant transmission of FHH1.
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Affiliation(s)
- Ida Marie Boisen
- Group of Skeletal, Mineral, and Gonadal Endocrinology, Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Iris Mos
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Anders Juul
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Hans Bräuner-Osborne
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Martin Blomberg Jensen
- Group of Skeletal, Mineral, and Gonadal Endocrinology, Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Division of Bone and Mineral Research, Harvard School of Dental Medicine/Harvard Medical School, Harvard University, Boston, MA, US
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Jørgensen CV, Bräuner‐Osborne H. Pharmacology and physiological function of the orphan GPRC6A receptor. Basic Clin Pharmacol Toxicol 2020; 126 Suppl 6:77-87. [DOI: 10.1111/bcpt.13397] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 02/11/2020] [Accepted: 02/11/2020] [Indexed: 12/17/2022]
Affiliation(s)
- Christinna V. Jørgensen
- Department of Drug Design and Pharmacology Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Hans Bräuner‐Osborne
- Department of Drug Design and Pharmacology Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
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13
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Quantification of aminobutyric acids and their clinical applications as biomarkers for osteoporosis. Commun Biol 2020; 3:39. [PMID: 31969651 PMCID: PMC6976694 DOI: 10.1038/s42003-020-0766-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 01/08/2020] [Indexed: 02/07/2023] Open
Abstract
Osteoporosis is a highly prevalent chronic aging-related disease that frequently is only detected after fracture. We hypothesized that aminobutyric acids could serve as biomarkers for osteoporosis. We developed a quick, accurate, and sensitive screening method for aminobutyric acid isomers and enantiomers yielding correlations with bone mineral density (BMD) and osteoporotic fracture. In serum, γ-aminobutyric acid (GABA) and (R)-3-aminoisobutyric acid (D-BAIBA) have positive associations with physical activity in young lean women. D-BAIBA positively associated with hip BMD in older individuals without osteoporosis/osteopenia. Lower levels of GABA were observed in 60–80 year old women with osteoporotic fractures. Single nucleotide polymorphisms in seven genes related to these metabolites associated with BMD and osteoporosis. In peripheral blood monocytes, dihydropyrimidine dehydrogenase, an enzyme essential to D-BAIBA generation, exhibited positive association with physical activity and hip BMD. Along with their signaling roles, BAIBA and GABA might serve as biomarkers for diagnosis and treatments of osteoporosis. Wang et al. develop an LC/MS based screening method to separate and quantify aminobutyric acids isoforms. Applying it to osteoporosis clinical studies, their method yields important correlations with bone mineral density and osteoporotic fracture and highlight the role of γ-aminobutyric acid and β-aminoisobutyric acid as biomarkers for osteoporosis.
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14
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Mos I, Jacobsen SE, Foster SR, Bräuner-Osborne H. Calcium-Sensing Receptor Internalization Isβ-Arrestin–Dependent and Modulated by Allosteric Ligands. Mol Pharmacol 2019; 96:463-474. [DOI: 10.1124/mol.119.116772] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 07/30/2019] [Indexed: 12/18/2022] Open
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15
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Ye R, Pi M, Nooh MM, Bahout SW, Quarles LD. Human GPRC6A Mediates Testosterone-Induced Mitogen-Activated Protein Kinases and mTORC1 Signaling in Prostate Cancer Cells. Mol Pharmacol 2019; 95:563-572. [PMID: 30894404 DOI: 10.1124/mol.118.115014] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 03/06/2019] [Indexed: 12/15/2022] Open
Abstract
G protein-coupled receptor family C group 6 member A (GPRC6A) is activated by testosterone and modulates prostate cancer progression. Most humans have a GPRC6A variant that contains a recently evolved KGKY insertion/deletion in the third intracellular loop (ICL3) (designated as GPRC6AICL3_KGKY) that replaces the ancestral KGRKLP sequence (GPRC6AICL3_RKLP) present in all other species. In vitro assays purport that human GPRC6AICL3_KGKY is retained intracellularly and lacks function. These findings contrast with ligand-dependent activation and coupling to mammalian target of rapamycin complex 1 (mTORC1) signaling of endogenous human GPRC6AICL3_KGKY in PC-3 cells. To understand these discrepant results, we expressed mouse (mGPRC6AICL3_KGRKLP), human (hGPRC6AICL3_KGKY), and humanized mouse (mGPRC6AICL3_KGKY) GPRC6A into human embryonic kidney 293 cells. Our results demonstrate that mGPRC6AICL3_KGRKLP acts as a classic G protein-coupled receptor, which is expressed at the cell membrane and internalizes in response to ligand activation by testosterone. In contrast, hGPRC6AICL3_KGKY and humanized mouse mGPRC6AICL3_KGKY are retained intracellularly in ligand naive cells, yet exhibit β-arrestin-dependent signaling responses, mitogen-activated protein kinase [i.e., extracellular signal-regulated kinase (ERK)], and p70S6 kinase phosphorylation in response to testosterone, indicating that hGPRC6AICL3_KGKY is functional. Indeed, testosterone stimulates time- and dose-dependent activation of ERK, protein kinase B, and mTORC1 signaling in wild-type PC-3 cells that express endogenous GPRC6AICL3_KGKY In addition, testosterone stimulates GPRC6A-dependent cell proliferation in wild-type PC-3 cells and inhibits autophagy by activating mTORC1 effectors eukaryotic translation initiation factor 4E binding protein 1 and Unc-51 like autophagy activating kinase 1. Testosterone activation of GPRC6A has the obligate requirement for calcium in the incubation media. In contrast, in GPRC6A-deficient cells, the effect of testosterone to activate downstream signaling is abolished, indicating that human GPRC6A is required for mediating the effects of testosterone on cell proliferation and autophagy.
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Affiliation(s)
- Ruisong Ye
- Departments of Medicine (R.Y., M.P., L.D.Q.) and Pharmacology (S.W.B.), University of Tennessee Health Science Center, Memphis, Tennessee; and Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt (M.M.N.)
| | - Min Pi
- Departments of Medicine (R.Y., M.P., L.D.Q.) and Pharmacology (S.W.B.), University of Tennessee Health Science Center, Memphis, Tennessee; and Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt (M.M.N.)
| | - Mohammed M Nooh
- Departments of Medicine (R.Y., M.P., L.D.Q.) and Pharmacology (S.W.B.), University of Tennessee Health Science Center, Memphis, Tennessee; and Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt (M.M.N.)
| | - Suleiman W Bahout
- Departments of Medicine (R.Y., M.P., L.D.Q.) and Pharmacology (S.W.B.), University of Tennessee Health Science Center, Memphis, Tennessee; and Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt (M.M.N.)
| | - L Darryl Quarles
- Departments of Medicine (R.Y., M.P., L.D.Q.) and Pharmacology (S.W.B.), University of Tennessee Health Science Center, Memphis, Tennessee; and Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt (M.M.N.)
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16
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Park J, Selvam B, Sanematsu K, Shigemura N, Shukla D, Procko E. Structural architecture of a dimeric class C GPCR based on co-trafficking of sweet taste receptor subunits. J Biol Chem 2019; 294:4759-4774. [PMID: 30723160 DOI: 10.1074/jbc.ra118.006173] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 01/24/2019] [Indexed: 01/06/2023] Open
Abstract
Class C G protein-coupled receptors (GPCRs) are obligatory dimers that are particularly important for neuronal responses to endogenous and environmental stimuli. Ligand recognition through large extracellular domains leads to the reorganization of transmembrane regions to activate G protein signaling. Although structures of individual domains are known, the complete architecture of a class C GPCR and the mechanism of interdomain coupling during receptor activation are unclear. By screening a mutagenesis library of the human class C sweet taste receptor subunit T1R2, we enhanced surface expression and identified a dibasic intracellular retention motif that modulates surface expression and co-trafficking with its heterodimeric partner T1R3. Using a highly expressed T1R2 variant, dimerization sites along the entire subunit within all the structural domains were identified by a comprehensive mutational scan for co-trafficking with T1R3 in human cells. The data further reveal that the C terminus of the extracellular cysteine-rich domain needs to be properly folded for T1R3 dimerization and co-trafficking, but not for surface expression of T1R2 alone. These results guided the modeling of the T1R2-T1R3 dimer in living cells, which predicts a twisted arrangement of domains around the central axis, and a continuous folded structure between transmembrane domain loops and the cysteine-rich domains. These insights have implications for how conformational changes between domains are coupled within class C GPCRs.
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Affiliation(s)
- Jihye Park
- From the Departments of Biochemistry and
| | - Balaji Selvam
- Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 and
| | - Keisuke Sanematsu
- the Section of Oral Neuroscience, Graduate School of Dental Science, and.,the Division of Sensory Physiology-Medical Application Sensing, Research and Development Center for Five-Sense Devices, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Noriatsu Shigemura
- the Section of Oral Neuroscience, Graduate School of Dental Science, and.,the Division of Sensory Physiology-Medical Application Sensing, Research and Development Center for Five-Sense Devices, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Diwakar Shukla
- Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 and
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17
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Kalyvianaki K, Panagiotopoulos AA, Malamos P, Moustou E, Tzardi M, Stathopoulos EN, Ioannidis GS, Marias K, Notas G, Theodoropoulos PA, Castanas E, Kampa M. Membrane androgen receptors (OXER1, GPRC6A AND ZIP9) in prostate and breast cancer: A comparative study of their expression. Steroids 2019; 142:100-108. [PMID: 30707908 DOI: 10.1016/j.steroids.2019.01.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 01/24/2019] [Indexed: 12/31/2022]
Abstract
Accumulating evidence during the last decades revealed that androgens exert membrane-initiated actions leading to the modulation of significant cellular processes, important for cancer cell growth and metastasis (including prostate and breast), that involve signaling via specific kinases. Collectively, many nonclassical, cell surface-initiated androgen actions are mediated by novel membrane androgen receptors (mARs), unrelated to nuclear androgen receptors. Recently, our group identified the G protein coupled oxo-eicosanoid receptor 1 (OXER1) (a receptor of the arachidonic acid metabolite, 5-oxoeicosatetraenoic acid, 5-oxoETE) as a novel mAR involved in the rapid effects of androgens. However, two other membrane proteins, G protein-coupled receptor family C group 6 member A (GPRC6A) and zinc transporter member 9 (ZIP9) have also been portrayed as mARs, related to the extranuclear action of androgens. In the present work, we present a comparative study of in silico pharmacology, gene expression and immunocytochemical data of the three receptors in various prostate and breast cancer cell lines. Furthermore, we analyzed the immunohistochemical expression of these receptors in human tumor and non-tumoral specimens and provide a pattern of expression and intracellular distribution.
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Affiliation(s)
- Konstantina Kalyvianaki
- Laboratory of Experimental Endocrinology, University of Crete, School of Medicine, Heraklion 71013, Greece
| | | | - Panagiotis Malamos
- Laboratory of Experimental Endocrinology, University of Crete, School of Medicine, Heraklion 71013, Greece
| | - Eleni Moustou
- Laboratory of Pathology, University of Crete, School of Medicine, Heraklion 71013, Greece
| | - Maria Tzardi
- Laboratory of Pathology, University of Crete, School of Medicine, Heraklion 71013, Greece
| | | | - Georgios S Ioannidis
- Foundation for Research and Technology - Hellas (FORTH), Institute of Computer Science (ICS), Computational Bio-Medicine Laboratory (CBML), Heraklion, Greece
| | - Kostas Marias
- Foundation for Research and Technology - Hellas (FORTH), Institute of Computer Science (ICS), Computational Bio-Medicine Laboratory (CBML), Heraklion, Greece; Technological Educational Institute of Crete, Department of Informatics Engineering, Heraklion, Greece
| | - George Notas
- Laboratory of Experimental Endocrinology, University of Crete, School of Medicine, Heraklion 71013, Greece
| | | | - Elias Castanas
- Laboratory of Experimental Endocrinology, University of Crete, School of Medicine, Heraklion 71013, Greece.
| | - Marilena Kampa
- Laboratory of Experimental Endocrinology, University of Crete, School of Medicine, Heraklion 71013, Greece.
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18
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Feng L, Wang J, Ma X. Exogenous SERP1 attenuates restenosis by restoring GLP-1 receptor activity in diabetic rats following vascular injury. Biomed Pharmacother 2018; 103:290-300. [PMID: 29656185 DOI: 10.1016/j.biopha.2018.04.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/05/2018] [Accepted: 04/05/2018] [Indexed: 10/17/2022] Open
Abstract
The activity of glucagon-like peptide 1 (GLP-1R) is essential for preventing restenosis following vascular injury; however, the mechanism of dysfunctional GLP-1R glycosylation and ways to enhance the activity of GLP-1R on vascular surfaces in diabetic patients are poorly understood. In the present study, we investigated the N-glycosylation level and role of stress-associated endoplasmic reticulum protein 1 (SERP1) in preventing restenosis following carotid injury in diabetic rats. Our results showed that N-glycosylation levels in both rat aortic endothelial cells (RAOECs) and rat vascular smooth muscle cells (VSMCs) decreased gradually following glucose treatment in a concentration dependant manner. Furthermore, co-immunoprecipitation (Co-IP) analyses indicated that SERP1 could interact with GLP-1R in RAOECs and VSMCs. Moreover, SERP1 enhanced GLP-1R N-glycosylation and increased the production of phosphorylated endothelial nitric oxide synthase (eNOS) as well as proliferation of RAOECs. SERP1 also increased phosphorylated adenosine monophosphate activated protein kinase (AMPK) and decreased the migration of VSMCs. Importantly, intima media thickness (IMT) and neointimal hyperplasia were alleviated in the carotid artery of diabetic rats injected with SERP1 following balloon injury. We also found an increase in re-endothelialization and a decrease in VSMC proliferation in the carotid artery of diabetic rats injected with SERP1. In summary, the remarkable effects of SERP1 on reducing restenosis following vascular injury may contribute to future advancements in the treatment of diabetic vascular complications.
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Affiliation(s)
- Lishuai Feng
- Department of Interventional Radiology, The Sixth People's Hospital Affiliated to Shanghai Jiaotong University, No 600 Yishan road, Xuhui District, Shanghai, 200233, China
| | - Jianbo Wang
- Department of Interventional Radiology, The Sixth People's Hospital Affiliated to Shanghai Jiaotong University, No 600 Yishan road, Xuhui District, Shanghai, 200233, China.
| | - Xu Ma
- Department of Interventional Radiology, The Sixth People's Hospital Affiliated to Shanghai Jiaotong University, No 600 Yishan road, Xuhui District, Shanghai, 200233, China
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19
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Cripwell RA, Rose SH, van Zyl WH. Expression and comparison of codon optimised Aspergillus tubingensis amylase variants in Saccharomyces cerevisiae. FEMS Yeast Res 2017. [DOI: 10.1093/femsyr/fox040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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20
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Investigating the molecular mechanism of positive and negative allosteric modulators in the calcium-sensing receptor dimer. Sci Rep 2017; 7:46355. [PMID: 28417952 PMCID: PMC5394417 DOI: 10.1038/srep46355] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 03/20/2017] [Indexed: 11/09/2022] Open
Abstract
Allosteric modulators that are targeting the calcium-sensing receptor (CaSR) hold great therapeutic potential, and elucidating the molecular basis for modulation would thus benefit the development of novel therapeutics. In the present study, we aimed at investigating the mechanism of allosteric modulation in CaSR by testing dimers carrying mutations in the allosteric site of one or both of the subunits. To ensure measurements on a well-defined dimer composition, we applied a trans-activation system in which only the specific heterodimer of two loss-of-function mutants responded to agonist. Although one of these mutants was potentiated by a positive allosteric modulator, we showed that receptor activity was further potentiated in a trans-activation heterodimer containing a single allosteric site, however only when the allosteric site was located in the subunit responsible for G protein coupling. On the contrary, preventing activation in both subunits was necessary for obtaining full inhibition by a negative allosteric modulator. These findings correlate with the proposed activation mechanism of the metabotropic glutamate receptors (mGluRs), in which only a single transmembrane domain is activated at a time. CaSR and mGluRs belong to the class C G protein-coupled receptors, and our findings thus suggest that the activation mechanism is common to this subfamily.
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21
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Jacobsen SE, Ammendrup-Johnsen I, Jansen AM, Gether U, Madsen KL, Bräuner-Osborne H. The GPRC6A receptor displays constitutive internalization and sorting to the slow recycling pathway. J Biol Chem 2017; 292:6910-6926. [PMID: 28280242 DOI: 10.1074/jbc.m116.762385] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 02/27/2017] [Indexed: 11/06/2022] Open
Abstract
The class C G protein-coupled receptor GPRC6A is a putative nutrient-sensing receptor and represents a possible new drug target in metabolic disorders. However, the specific physiological role of this receptor has yet to be identified, and the mechanisms regulating its activity and cell surface availability also remain enigmatic. In the present study, we investigated the trafficking properties of GPRC6A by use of both a classical antibody feeding internalization assay in which cells were visualized using confocal microscopy and a novel internalization assay that is based on real-time measurements of fluorescence resonance energy transfer. Both assays revealed that GPRC6A predominantly undergoes constitutive internalization, whereas the agonist-induced effects were imperceptible. Moreover, postendocytic sorting was investigated by assessing the co-localization of internalized GPRC6A with selected Rab protein markers. Internalized GPRC6A was mainly co-localized with the early endosome marker Rab5 and the long loop recycling endosome marker Rab11 and to a much lesser extent with the late endosome marker Rab7. This suggests that upon agonist-independent internalization, GPRC6A is recycled via the Rab11-positive slow recycling pathway, which may be responsible for ensuring a persistent pool of GPRC6A receptors at the cell surface despite chronic agonist exposure. Distinct trafficking pathways have been reported for several of the class C receptors, and our results thus substantiate that non-canonical trafficking mechanisms are a common feature for the nutrient-sensing class C family that ensure functional receptors in the cell membrane despite prolonged agonist exposure.
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Affiliation(s)
- Stine Engesgaard Jacobsen
- From the Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark and
| | - Ina Ammendrup-Johnsen
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Anna Mai Jansen
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Ulrik Gether
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Kenneth Lindegaard Madsen
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Hans Bräuner-Osborne
- From the Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark and
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22
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Jørgensen S, Have CT, Underwood CR, Johansen LD, Wellendorph P, Gjesing AP, Jørgensen CV, Quan S, Rui G, Inoue A, Linneberg A, Grarup N, Jun W, Pedersen O, Hansen T, Bräuner-Osborne H. Genetic Variations in the Human G Protein-coupled Receptor Class C, Group 6, Member A (GPRC6A) Control Cell Surface Expression and Function. J Biol Chem 2016; 292:1524-1534. [PMID: 27986810 DOI: 10.1074/jbc.m116.756577] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/14/2016] [Indexed: 12/30/2022] Open
Abstract
GPRC6A is a G protein-coupled receptor activated by l-amino acids, which, based on analyses of knock-out mice, has been suggested to have physiological functions in metabolism and testicular function. The human ortholog is, however, mostly retained intracellularly in contrast to the cell surface-expressed murine and goldfish orthologs. The latter orthologs are Gq-coupled and lead to intracellular accumulation of inositol phosphates and calcium release. In the present study we cloned the bonobo chimpanzee GPRC6A receptor, which is 99% identical to the human receptor, and show that it is cell surface-expressed and functional. By analyses of chimeric human/mouse and human/bonobo receptors, bonobo receptor mutants, and the single nucleotide polymorphism database at NCBI, we identify an insertion/deletion variation in the third intracellular loop responsible for the intracellular retention and lack of function of the human ortholog. Genetic analyses of the 1000 genome database and the Inter99 cohort of 6,000 Danes establish the distribution of genotypes among ethnic groups, showing that the cell surface-expressed and functional variant is much more prevalent in the African population than in European and Asian populations and that this variant is partly linked with a stop codon early in the receptor sequence (rs6907580, amino acid position 57). In conclusion, our data solve a more than decade-old question of why the cloned human GPRC6A receptor is not cell surface-expressed and functional and provide a genetic framework to study human phenotypic traits in large genome sequencing projects linked with physiological measurement and biomarkers.
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Affiliation(s)
- Stine Jørgensen
- From the Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Christian Theil Have
- the Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Christina Rye Underwood
- From the Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Lars Dan Johansen
- From the Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Petrine Wellendorph
- From the Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Anette Prior Gjesing
- the Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Christinna V Jørgensen
- From the Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Shi Quan
- BGI-Shenzhen, Shenzhen 518083, China
| | - Gao Rui
- BGI-Shenzhen, Shenzhen 518083, China
| | - Asuka Inoue
- the Laboratory of Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan.,the Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology, Kawaguchi, Saitama 332-0012, Japan
| | - Allan Linneberg
- the Research Centre for Prevention and Health, Capital Region of Denmark, DK-2600 Glostrup, Denmark.,the Department of Clinical Experimental Research, Rigshospitalet, DK-2100 Copenhagen, Denmark, and.,the Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Niels Grarup
- the Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Wang Jun
- BGI-Shenzhen, Shenzhen 518083, China
| | - Oluf Pedersen
- the Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Torben Hansen
- the Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Hans Bräuner-Osborne
- From the Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark,
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23
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Lv X, Liu J, Shi Q, Tan Q, Wu D, Skinner JJ, Walker AL, Zhao L, Gu X, Chen N, Xue L, Si P, Zhang L, Wang Z, Katritch V, Liu ZJ, Stevens RC. In vitro expression and analysis of the 826 human G protein-coupled receptors. Protein Cell 2016; 7:325-37. [PMID: 27085723 PMCID: PMC4853319 DOI: 10.1007/s13238-016-0263-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 03/09/2016] [Indexed: 01/24/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are involved in all human physiological systems where they are responsible for transducing extracellular signals into cells. GPCRs signal in response to a diverse array of stimuli including light, hormones, and lipids, where these signals affect downstream cascades to impact both health and disease states. Yet, despite their importance as therapeutic targets, detailed molecular structures of only 30 GPCRs have been determined to date. A key challenge to their structure determination is adequate protein expression. Here we report the quantification of protein expression in an insect cell expression system for all 826 human GPCRs using two different fusion constructs. Expression characteristics are analyzed in aggregate and among each of the five distinct subfamilies. These data can be used to identify trends related to GPCR expression between different fusion constructs and between different GPCR families, and to prioritize lead candidates for future structure determination feasibility.
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Affiliation(s)
- Xuechen Lv
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Junlin Liu
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Qiaoyun Shi
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Qiwen Tan
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Dong Wu
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - John J Skinner
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Angela L Walker
- Department of Biological Sciences, Bridge Institute, University of Southern California, Los Angeles, CA, 90089, USA
| | - Lixia Zhao
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Xiangxiang Gu
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Na Chen
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Lu Xue
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Pei Si
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Lu Zhang
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Zeshi Wang
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Vsevolod Katritch
- Department of Biological Sciences, Bridge Institute, University of Southern California, Los Angeles, CA, 90089, USA
| | - Zhi-Jie Liu
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
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24
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Johansson H, Boesgaard MW, Nørskov-Lauritsen L, Larsen I, Kuhne S, Gloriam DE, Bräuner-Osborne H, Sejer Pedersen D. Selective Allosteric Antagonists for the G Protein-Coupled Receptor GPRC6A Based on the 2-Phenylindole Privileged Structure Scaffold. J Med Chem 2015; 58:8938-51. [PMID: 26516782 DOI: 10.1021/acs.jmedchem.5b01254] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
G protein-coupled receptors (GPCRs) represent a biological target class of fundamental importance in drug therapy. The GPRC6A receptor is a newly deorphanized class C GPCR that we recently reported for the first allosteric antagonists based on the 2-arylindole privileged structure scaffold (e.g., 1-3). Herein, we present the first structure-activity relationship study for the 2-arylindole antagonist 3, comprising the design, synthesis, and pharmacological evaluation of a focused library of 3-substituted 2-arylindoles. In a FRET-based inositol monophosphate (IP1) assay we identified compounds 7, 13e, and 34b as antagonists at the GPRC6A receptor in the low micromolar range and show that 7 and 34b display >9-fold selectivity for the GPRC6A receptor over related GPCRs, making 7 and 34b the most potent and selective antagonists for the GPRC6A receptor reported to date.
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Affiliation(s)
- Henrik Johansson
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Jagtvej 162, 2100 Copenhagen, Denmark
| | - Michael Worch Boesgaard
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Jagtvej 162, 2100 Copenhagen, Denmark
| | - Lenea Nørskov-Lauritsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Jagtvej 162, 2100 Copenhagen, Denmark
| | - Inna Larsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Jagtvej 162, 2100 Copenhagen, Denmark
| | - Sebastiaan Kuhne
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Jagtvej 162, 2100 Copenhagen, Denmark
| | - David E Gloriam
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Jagtvej 162, 2100 Copenhagen, Denmark
| | - Hans Bräuner-Osborne
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Jagtvej 162, 2100 Copenhagen, Denmark
| | - Daniel Sejer Pedersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Jagtvej 162, 2100 Copenhagen, Denmark
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25
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Piscitelli CL, Kean J, de Graaf C, Deupi X. A Molecular Pharmacologist's Guide to G Protein-Coupled Receptor Crystallography. Mol Pharmacol 2015; 88:536-51. [PMID: 26152196 DOI: 10.1124/mol.115.099663] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/07/2015] [Indexed: 12/14/2022] Open
Abstract
G protein-coupled receptor (GPCR) structural biology has progressed dramatically in the last decade. There are now over 120 GPCR crystal structures deposited in the Protein Data Bank of 32 different receptors from families scattered across the phylogenetic tree, including class B, C, and Frizzled GPCRs. These structures have been obtained in combination with a wide variety of ligands and captured in a range of conformational states. This surge in structural knowledge has enlightened research into the molecular recognition of biologically active molecules, the mechanisms of receptor activation, the dynamics of functional selectivity, and fueled structure-based drug design efforts for GPCRs. Here we summarize the innovations in both protein engineering/molecular biology and crystallography techniques that have led to these advances in GPCR structural biology and discuss how they may influence the resulting structural models. We also provide a brief molecular pharmacologist's guide to GPCR X-ray crystallography, outlining some key aspects in the process of structure determination, with the goal to encourage noncrystallographers to interrogate structures at the molecular level. Finally, we show how chemogenomics approaches can be used to marry the wealth of existing receptor pharmacology data with the expanding repertoire of structures, providing a deeper understanding of the mechanistic details of GPCR function.
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Affiliation(s)
- Chayne L Piscitelli
- Laboratory of Biomolecular Research, Department of Biology and Chemistry (C.L.P., X.D.), and Condensed Matter Theory Group, Department of Research with Neutrons and Muons (X.D.), Paul Scherrer Institute, Villigen, Switzerland; Heptares Therapeutics Ltd., Welwyn Garden City, United Kingdom (J.K.); and Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems, VU University of Amsterdam, Amsterdam, The Netherlands (C.G.)
| | - James Kean
- Laboratory of Biomolecular Research, Department of Biology and Chemistry (C.L.P., X.D.), and Condensed Matter Theory Group, Department of Research with Neutrons and Muons (X.D.), Paul Scherrer Institute, Villigen, Switzerland; Heptares Therapeutics Ltd., Welwyn Garden City, United Kingdom (J.K.); and Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems, VU University of Amsterdam, Amsterdam, The Netherlands (C.G.)
| | - Chris de Graaf
- Laboratory of Biomolecular Research, Department of Biology and Chemistry (C.L.P., X.D.), and Condensed Matter Theory Group, Department of Research with Neutrons and Muons (X.D.), Paul Scherrer Institute, Villigen, Switzerland; Heptares Therapeutics Ltd., Welwyn Garden City, United Kingdom (J.K.); and Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems, VU University of Amsterdam, Amsterdam, The Netherlands (C.G.)
| | - Xavier Deupi
- Laboratory of Biomolecular Research, Department of Biology and Chemistry (C.L.P., X.D.), and Condensed Matter Theory Group, Department of Research with Neutrons and Muons (X.D.), Paul Scherrer Institute, Villigen, Switzerland; Heptares Therapeutics Ltd., Welwyn Garden City, United Kingdom (J.K.); and Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems, VU University of Amsterdam, Amsterdam, The Netherlands (C.G.)
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26
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Role of post-translational modifications on structure, function and pharmacology of class C G protein-coupled receptors. Eur J Pharmacol 2015; 763:233-40. [PMID: 25981296 DOI: 10.1016/j.ejphar.2015.05.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 03/06/2015] [Accepted: 05/11/2015] [Indexed: 11/22/2022]
Abstract
G protein-coupled receptors are divided into three classes (A, B and C) based on homology of their seven transmembrane domains. Class C is the smallest class with 22 human receptor subtypes including eight metabotropic glutamate (mGlu1-8) receptors, two GABAB receptors (GABAB1 and GABAB2), three taste receptors (T1R1-3), one calcium-sensing (CaS) receptor, one GPCR, class C, group 6, subtype A (GPRC6) receptor, and seven orphan receptors. G protein-coupled receptors undergo a number of post-translational modifications, which regulate their structure, function and/or pharmacology. Here, we review the existence of post-translational modifications in class C G protein-coupled receptors and their regulatory roles, with particular focus on glycosylation, phosphorylation, ubiquitination, SUMOylation, disulphide bonding and lipidation.
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