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Wu KC, Leong IL, Leung YM. Ca 2+-sensing receptor-TRP channel-mediated Ca 2+ signaling: Functional diversity and pharmacological complexity. Eur J Pharmacol 2024; 977:176717. [PMID: 38857682 DOI: 10.1016/j.ejphar.2024.176717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 05/07/2024] [Accepted: 06/05/2024] [Indexed: 06/12/2024]
Abstract
The Ca2+-sensing receptor (CaSR) is a G-protein-coupled receptor activated by elevated concentrations of extracellular Ca2+, and was initially known for its regulation of parathyroid hormone (PTH) release. Ubiquitous expression of CaSR in different tissues and organs was later noted and CaSR participation in various physiological functions was demonstrated. Accumulating evidence has suggested that CaSR functionally interacts with transient receptor potential (TRP) channels, which are mostly non-selective cation channels involved in sensing temperature, pain and stress. This review describes the interactions of CaSR with TRP channels in diverse cell types to trigger a variety of biological responses. CaSR has been known to interact with different types of G proteins. Possible involvements of G proteins, other signaling and scaffolding protein intermediates in CaSR-TRP interaction are discussed. In addition, an attempt will be made to extend the current understanding of biased agonism of CaSR.
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Affiliation(s)
- King-Chuen Wu
- Department of Anesthesiology, Chang Gung Memorial Hospital, Chiayi, Taiwan; Chang Gung University of Science and Technology, Chiayi, Taiwan; Shu-Zen Junior College of Medicine and Management, Kaohsiung, Taiwan
| | - Iat-Lon Leong
- Division of Cardiology, University Hospital, Macau University of Science and Technology, Macau
| | - Yuk-Man Leung
- Department of Physiology, China Medical University, Taichung, Taiwan.
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2
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Zuo H, Park J, Frangaj A, Ye J, Lu G, Manning JJ, Asher WB, Lu Z, Hu GB, Wang L, Mendez J, Eng E, Zhang Z, Lin X, Grassucci R, Hendrickson WA, Clarke OB, Javitch JA, Conigrave AD, Fan QR. Promiscuous G-protein activation by the calcium-sensing receptor. Nature 2024; 629:481-488. [PMID: 38632411 DOI: 10.1038/s41586-024-07331-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 03/18/2024] [Indexed: 04/19/2024]
Abstract
The human calcium-sensing receptor (CaSR) detects fluctuations in the extracellular Ca2+ concentration and maintains Ca2+ homeostasis1,2. It also mediates diverse cellular processes not associated with Ca2+ balance3-5. The functional pleiotropy of CaSR arises in part from its ability to signal through several G-protein subtypes6. We determined structures of CaSR in complex with G proteins from three different subfamilies: Gq, Gi and Gs. We found that the homodimeric CaSR of each complex couples to a single G protein through a common mode. This involves the C-terminal helix of each Gα subunit binding to a shallow pocket that is formed in one CaSR subunit by all three intracellular loops (ICL1-ICL3), an extended transmembrane helix 3 and an ordered C-terminal region. G-protein binding expands the transmembrane dimer interface, which is further stabilized by phospholipid. The restraint imposed by the receptor dimer, in combination with ICL2, enables G-protein activation by facilitating conformational transition of Gα. We identified a single Gα residue that determines Gq and Gs versus Gi selectivity. The length and flexibility of ICL2 allows CaSR to bind all three Gα subtypes, thereby conferring capacity for promiscuous G-protein coupling.
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MESH Headings
- Humans
- Calcium/metabolism
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- GTP-Binding Protein alpha Subunits, Gi-Go/chemistry
- GTP-Binding Protein alpha Subunits, Gq-G11/metabolism
- GTP-Binding Protein alpha Subunits, Gq-G11/chemistry
- GTP-Binding Protein alpha Subunits, Gs/metabolism
- GTP-Binding Protein alpha Subunits, Gs/chemistry
- Models, Molecular
- Protein Binding
- Protein Multimerization
- Receptors, Calcium-Sensing/metabolism
- Receptors, Calcium-Sensing/chemistry
- Heterotrimeric GTP-Binding Proteins/chemistry
- Heterotrimeric GTP-Binding Proteins/metabolism
- Binding Sites
- Protein Structure, Secondary
- Substrate Specificity
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Affiliation(s)
- Hao Zuo
- Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY, USA
| | - Jinseo Park
- Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY, USA
| | - Aurel Frangaj
- Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY, USA
| | - Jianxiang Ye
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Guanqi Lu
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Jamie J Manning
- Department of Psychiatry, Columbia University, New York, NY, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Wesley B Asher
- Department of Psychiatry, Columbia University, New York, NY, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Zhengyuan Lu
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Guo-Bin Hu
- Laboratory for BioMolecular Structure, Brookhaven National Laboratory, Upton, NY, USA
| | - Liguo Wang
- Laboratory for BioMolecular Structure, Brookhaven National Laboratory, Upton, NY, USA
| | - Joshua Mendez
- National Center for Cryo-EM Access and Training, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Edward Eng
- National Center for Cryo-EM Access and Training, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Zhening Zhang
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Xin Lin
- Department of Psychiatry, Columbia University, New York, NY, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Robert Grassucci
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Wayne A Hendrickson
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Oliver B Clarke
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
- Department of Anesthesiology, Columbia University, New York, NY, USA
- Irving Institute for Clinical and Translational Research, Columbia University, New York, NY, USA
| | - Jonathan A Javitch
- Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY, USA.
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA.
- Department of Psychiatry, Columbia University, New York, NY, USA.
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA.
| | - Arthur D Conigrave
- School of Life & Environmental Sciences, Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia.
| | - Qing R Fan
- Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY, USA.
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA.
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3
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Gorvin CM. Recent advances in calcium-sensing receptor structures and signaling pathways. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 195:121-135. [PMID: 36707151 DOI: 10.1016/bs.pmbts.2022.06.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The calcium-sensing receptor (CaSR) is a class C GPCR that has a fundamental role in extracellular calcium homeostasis by regulating parathyroid hormone release and urinary calcium excretion. Germline mutations in the receptor cause disorders of calcium homeostasis and studies of the functional effects of these mutations has facilitated understanding of CaSR signaling and how allosteric modulators affect these responses. In the past year, five cryo-EM structures of the near full-length CaSR have been published, demonstrating how agonist-binding transmits changes in the CaSR extracellular domain to the transmembrane region to activate G proteins, and how allosteric modulators affect these structural dynamics. Additionally, several recent studies have identified CaSR interacting proteins that regulate CaSR signaling and trafficking and contribute to understanding how the receptor achieves rapid and diverse physiological responses.
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Affiliation(s)
- Caroline M Gorvin
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Birmingham, United Kingdom; Institute of Metabolism and Systems Research (IMSR) and Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, University of Birmingham, Birmingham, United Kingdom.
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4
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Leong IL, Yu CM, Shiao LR, Chan P, Wu KC, Leung YM. Sensitivity of Ca 2+-sensing receptor-transient receptor potential-mediated Ca 2+ influx to extracellular acidity in bEND.3 endothelial cells. CHINESE J PHYSIOL 2022; 65:277-281. [PMID: 36588353 DOI: 10.4103/0304-4920.365460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Ca2+-sensing receptors (CaSRs) are G protein-coupled receptors activated by elevated concentrations of extracellular Ca2+. In our previous works, we showed protein and functional expression of CaSR in mouse cerebral endothelial cell (EC) (bEND.3); the CaSR response (high Ca2+-elicited cytosolic [Ca2+] elevation) was unaffected by suppression of phospholipase C but in part involved Ca2+ influx through transient receptor potential V1 (TRPV1) channels. In this work, we investigated if extracellular acidity affected CaSR-mediated Ca2+ influx triggered by high (3 mM) Ca2+ (CaSR agonist), 3 mM spermine (CaSR agonist), and 10 mM cinacalcet (positive allosteric modulator of CaSR). Extracellular acidosis (pH 6.8 and pH 6.0) strongly suppressed cytosolic [Ca2+] elevation triggered by high Ca2+, spermine, and cinacalcet; acidosis also inhibited Mn2+ influx stimulated by high Ca2+ and cinacalcet. Purinoceptor-triggered Ca2+ response, however, was not suppressed by acidosis. Extracellular acidity also did not affect membrane potential, suggesting suppressed CaSR-mediated Ca2+ influx in acidity did not result from the reduced electrical driving force for Ca2+. Our results suggest Ca2+ influx through a putative CaSR-TRP complex in bEND.3 EC was sensitive to extracellular pH.
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Affiliation(s)
- Iat-Lon Leong
- Division of Cardiology, Department of Internal Medicine, Kiang Wu Hospital, Macau, China
| | - Chung-Ming Yu
- Department of Anesthesiology, Chang Gung Memorial Hospital, Chiayi, Taiwan
| | - Lian-Ru Shiao
- Department of Physiology, China Medical University, Taichung, Taiwan
| | - Paul Chan
- Division of Cardiology, Department of Medicine, Taipei Medical University Wan Fang Hospital, Taipei, Taiwan
| | - King-Chuen Wu
- Department of Anesthesiology, Chang Gung Memorial Hospital, Chiayi; Department of Nursing, Chang Gung University of Science and Technology, Chiayi; Department of Information Management, Shu-Zen Junior College of Medicine and Management, Kaohsiung, Taiwan
| | - Yuk-Man Leung
- Department of Physiology, China Medical University, Taichung, Taiwan
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5
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Calcium-Sensing Receptor (CaSR)-Mediated Intracellular Communication in Cardiovascular Diseases. Cells 2022; 11:cells11193075. [PMID: 36231037 PMCID: PMC9562006 DOI: 10.3390/cells11193075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/31/2022] [Accepted: 09/23/2022] [Indexed: 11/17/2022] Open
Abstract
The calcium-sensing receptor (CaSR), a G-protein-coupled receptor (GPCR), is a cell-surface-located receptor that can induce highly diffusible messengers (IP3, Ca2+, cAMP) in the cytoplasm to activate various cellular responses. Recently, it has also been suggested that the CaSR mediates the intracellular communications between the endoplasmic reticulum (ER), mitochondria, nucleus, protease/proteasome, and autophagy-lysosome, which are involved in related cardiovascular diseases. The complex intracellular signaling of this receptor challenges it as a valuable therapeutic target. It is, therefore, necessary to understand the mechanisms behind the signaling characteristics of this receptor in intracellular communication. This review provides an overview of the recent research progress on the various regulatory mechanisms of the CaSR in related cardiovascular diseases and the heart-kidney interaction; the associated common causes are also discussed.
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6
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Lines KE, Gluck AK, Thongjuea S, Bountra C, Thakker RV, Gorvin CM. The bromodomain inhibitor JQ1+ reduces calcium-sensing receptor activity in pituitary cell lines. J Mol Endocrinol 2021; 67:83-94. [PMID: 34223822 PMCID: PMC8345903 DOI: 10.1530/jme-21-0030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 07/05/2021] [Indexed: 12/05/2022]
Abstract
Corticotrophinomas represent 10% of all surgically removed pituitary adenomas, however, current treatment options are often not effective, and there is a need for improved pharmacological treatments. Recently, JQ1+, a bromodomain inhibitor that promotes gene transcription by binding acetylated histone residues and recruiting transcriptional machinery, has been shown to reduce proliferation in a murine corticotroph cell line, AtT20. RNA-Seq analysis of AtT20 cells following treatment with JQ1+ identified the calcium-sensing receptor (CaSR) gene as significantly downregulated, which was subsequently confirmed using real-time PCR and Western blot analysis. CaSR is a G protein-coupled receptor that plays a central role in calcium homeostasis but can elicit non-calcitropic effects in multiple tissues, including the anterior pituitary where it helps regulate hormone secretion. However, in AtT20 cells, CaSR activates a tumour-specific cAMP pathway that promotes ACTH and PTHrP hypersecretion. We hypothesised that the Casr promoter may harbour binding sites for BET proteins, and using chromatin immunoprecipitation (ChIP)-sequencing demonstrated that the BET protein Brd3 binds to the promoter of the Casr gene. Assessment of CaSR signalling showed that JQ1+ significantly reduced Ca2+e-mediated increases in intracellular calcium (Ca2+i) mobilisation and cAMP signalling. However, the CaSR-negative allosteric modulator, NPS-2143, was unable to reduce AtT20 cell proliferation, indicating that reducing CaSR expression rather than activity is likely required to reduce pituitary cell proliferation. Thus, these studies demonstrate that reducing CaSR expression may be a viable option in the treatment of pituitary tumours. Moreover, current strategies to reduce CaSR activity, rather than protein expression for cancer treatments, may be ineffective.
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Affiliation(s)
- Kate E Lines
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford,UK
- Correspondence should be addressed to K E Lines or C M Gorvin: or
| | - Anna K Gluck
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford,UK
| | - Supat Thongjuea
- Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Chas Bountra
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Rajesh V Thakker
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford,UK
| | - Caroline M Gorvin
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford,UK
- Institute of Metabolism and Systems Research and Centre for Endocrinology, Diabetes and Metabolism, University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
- Correspondence should be addressed to K E Lines or C M Gorvin: or
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7
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Abid HA, Inoue A, Gorvin CM. Heterogeneity of G protein activation by the calcium-sensing receptor. J Mol Endocrinol 2021; 67:41-53. [PMID: 34077389 PMCID: PMC8240730 DOI: 10.1530/jme-21-0058] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/02/2021] [Indexed: 12/20/2022]
Abstract
The calcium-sensing receptor (CaSR) is a G protein-coupled receptor that plays a fundamental role in extracellular calcium (Ca2+e) homeostasis by regulating parathyroid hormone release and urinary calcium excretion. The CaSR has been described to activate all four G protein subfamilies (Gαq/11, Gαi/o, Gα12/13, Gαs), and mutations in the receptor that cause hyper/hypocalcaemia, have been described to bias receptor signalling. However, many of these studies are based on measurements of second messengers or gene transcription that occurs many steps downstream of receptor activation and can represent convergence points of several signalling pathways. Therefore, to assess CaSR-mediated G protein activation directly, we took advantage of a recently described NanoBiT G protein dissociation assay system. Our studies, performed in HEK293 cells stably expressing CaSR, demonstrate that Ca2+e stimulation activates all Gαq/11 family and several Gαi/o family proteins, although Gαz was not activated. CaSR stimulated dissociation of Gα12/13 and Gαs from Gβ-subunits, but this occurred at a slower rate than that of other Gα-subunits. Investigation of cDNA expression of G proteins in three tissues abundantly expressing CaSR, the parathyroids, kidneys and pancreas, showed Gα11, Gαz, Gαi1 and Gα13 genes were highly expressed in parathyroid tissue, indicating CaSR most likely activates Gα11 and Gαi1 in parathyroids. In kidney and pancreas, the majority of G proteins were similarly expressed, suggesting CaSR may activate multiple G proteins in these cells. Thus, these studies validate a single assay system that can be used to robustly assess CaSR variants and biased signalling and could be utilised in the development of new pharmacological compounds targeting CaSR.
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Affiliation(s)
- Hasnat Ali Abid
- Institute of Metabolism and Systems Research and Centre for Endocrinology, Diabetes and Metabolism, University of Birmingham, Birmingham, UK
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Caroline M Gorvin
- Institute of Metabolism and Systems Research and Centre for Endocrinology, Diabetes and Metabolism, University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, UK
- Correspondence should be addressed to C M Gorvin:
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8
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Leong IL, Tsai TY, Shiao LR, Zhang YM, Wong KL, Chan P, Leung YM. Characterization of Ca 2+-Sensing Receptor-Mediated Ca 2+ Influx in Microvascular bEND.3 Endothelial Cells. CHINESE J PHYSIOL 2021; 64:80-87. [PMID: 33938818 DOI: 10.4103/cjp.cjp_93_20] [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] [Indexed: 11/04/2022] Open
Abstract
Ca2+-sensing receptors (CaSR), activated by elevated concentrations of extracellular Ca2+, have been known to regulate functions of thyroid cells, neurons, and endothelial cells (EC). In this report, we studied CaSR-mediated Ca2+ influx in mouse cerebral microvascular EC (bEND.3 cells). Cytosolic free Ca2+ concentration and Mn2+ influx were measured by fura-2 microfluorometry. High (3 mM) Ca2+ (CaSR agonist), 3 mM spermine (CaSR agonist), and 10 μM cinacalcet (positive allosteric modulator of CaSR) all triggered Ca2+ influx; however, spermine, unlike high Ca2+ and cinacalcet, did not promote Mn2+ influx and its response was poorly sensitive to SKF 96365, a TRP channel blocker. Consistently, 2-aminoethoxydiphenyl borate and ruthenium red (two other general TRP channel blockers) suppressed Ca2+ influx triggered by cinacalcet and high Ca2+ but not by spermine. Ca2+ influx triggered by high Ca2+, spermine, and cinacalcet was similarly suppressed by A784168, a potent and selective TRPV1 antagonist. Our results suggest that CaSR activation triggered Ca2+ influx via TRPV1 channels; intriguingly, pharmacological, and permeability properties of such Ca2+ influx depended on the stimulating ligands.
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Affiliation(s)
- Iat-Lon Leong
- Department of Internal Medicine, Division of Cardiology, Kiang Wu Hospital, Macau, China
| | - Tien-Yao Tsai
- Cardiovascular Division, Fu Jen Catholic University Hospital, Fu Jen Catholic University, New Taipei City; Department of Cardiology, Lotung Poh-Ai Hospital, Yilan County, Taiwan
| | - Lian-Ru Shiao
- Department of Physiology, China Medical University, Taichung, Taiwan
| | - Yu-Mei Zhang
- VIP Department, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Kar-Lok Wong
- Department of Anesthesiology, China Medical University Hospital; Department of Anesthesiology, Kuang Tien General Hospital, Taichung, Taiwan
| | - Paul Chan
- Division of Cardiology, Department of Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Yuk-Man Leung
- Department of Physiology, China Medical University, Taichung, Taiwan
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9
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Tan RSG, Lee CHL, Dimke H, Todd Alexander R. The role of calcium-sensing receptor signaling in regulating transepithelial calcium transport. Exp Biol Med (Maywood) 2021; 246:2407-2419. [PMID: 33926258 DOI: 10.1177/15353702211010415] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The calcium-sensing receptor (CaSR) plays a critical role in sensing extracellular calcium (Ca2+) and signaling to maintain Ca2+ homeostasis. In the parathyroid, the CaSR regulates secretion of parathyroid hormone, which functions to increase extracellular Ca2+ levels. The CaSR is also located in other organs imperative to Ca2+ homeostasis including the kidney and intestine, where it modulates Ca2+ reabsorption and absorption, respectively. In this review, we describe CaSR expression and its function in transepithelial Ca2+ transport in the kidney and intestine. Activation of the CaSR leads to G protein dependent and independent signaling cascades. The known CaSR signal transduction pathways involved in modulating paracellular and transcellular epithelial Ca2+ transport are discussed. Mutations in the CaSR cause a range of diseases that manifest in altered serum Ca2+ levels. Gain-of-function mutations in the CaSR result in autosomal dominant hypocalcemia type 1, while loss-of-function mutations cause familial hypocalciuric hypercalcemia. Additionally, the putative serine protease, FAM111A, is discussed as a potential regulator of the CaSR because mutations in FAM111A cause Kenny Caffey syndrome type 2, gracile bone dysplasia, and osteocraniostenosis, diseases that are characterized by hypocalcemia, hypoparathyroidism, and bony abnormalities, i.e. share phenotypic features of autosomal dominant hypocalcemia. Recent work has helped to elucidate the effect of CaSR signaling cascades on downstream proteins involved in Ca2+ transport across renal and intestinal epithelia; however, much remains to be discovered.
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Affiliation(s)
- Rebecca Siu Ga Tan
- Department of Physiology, University of Alberta, Edmonton T6G 1C9, Canada.,Membrane Protein Disease Research Group, University of Alberta, Edmonton T6G 1C9, Canada
| | | | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense 5000, Denmark.,Department of Nephrology, Odense University Hospital, Odense 5000, Denmark
| | - R Todd Alexander
- Department of Physiology, University of Alberta, Edmonton T6G 1C9, Canada.,Membrane Protein Disease Research Group, University of Alberta, Edmonton T6G 1C9, Canada.,Department of Pediatrics, University of Alberta, Edmonton T6G 1C9, Canada
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10
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Diao J, DeBono A, Josephs TM, Bourke JE, Capuano B, Gregory KJ, Leach K. Therapeutic Opportunities of Targeting Allosteric Binding Sites on the Calcium-Sensing Receptor. ACS Pharmacol Transl Sci 2021; 4:666-679. [PMID: 33860192 DOI: 10.1021/acsptsci.1c00046] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Indexed: 01/24/2023]
Abstract
The CaSR is a class C G protein-coupled receptor (GPCR) that acts as a multimodal chemosensor to maintain diverse homeostatic functions. The CaSR is a clinical therapeutic target in hyperparathyroidism and has emerged as a putative target in several other diseases. These include hyper- and hypocalcaemia caused either by mutations in the CASR gene or in genes that regulate CaSR signaling and expression, and more recently in asthma. The development of CaSR-targeting drugs is complicated by the fact that the CaSR possesses many different binding sites for endogenous and exogenous agonists and allosteric modulators. Binding sites for endogenous and exogenous ligands are located throughout the large CaSR protein and are interconnected in ways that we do not yet fully understand. This review summarizes our current understanding of CaSR physiology, signaling, and structure and how the many different binding sites of the CaSR may be targeted to treat disease.
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Affiliation(s)
- Jiayin Diao
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Aaron DeBono
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia.,Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Tracy M Josephs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Jane E Bourke
- Department of Pharmacology, Biomedicine Discovery Institute, Monash University, 9 Ancora Imparo Way, Clayton, Victoria 3800, Australia
| | - Ben Capuano
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Karen J Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia.,Department of Pharmacology, Biomedicine Discovery Institute, Monash University, 9 Ancora Imparo Way, Clayton, Victoria 3800, Australia
| | - Katie Leach
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia.,Department of Pharmacology, Biomedicine Discovery Institute, Monash University, 9 Ancora Imparo Way, Clayton, Victoria 3800, Australia
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11
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Yes-Associated Protein 1 Is a Novel Calcium Sensing Receptor Target in Human Parathyroid Tumors. Int J Mol Sci 2021; 22:ijms22042016. [PMID: 33670622 PMCID: PMC7922006 DOI: 10.3390/ijms22042016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 02/15/2021] [Accepted: 02/16/2021] [Indexed: 12/23/2022] Open
Abstract
The Hippo pathway is involved in human tumorigenesis and tissue repair. Here, we investigated the Hippo coactivator Yes-associated protein 1 (YAP1) and the kinase large tumor suppressor 1/2 (LATS1/2) in tumors of the parathyroid glands, which are almost invariably associated with primary hyperparathyroidism. Compared with normal parathyroid glands, parathyroid adenomas (PAds) and carcinomas show variably but reduced nuclear YAP1 expression. The kinase LATS1/2, which phosphorylates YAP1 thus promoting its degradation, was also variably reduced in PAds. Further, YAP1 silencing reduces the expression of the key parathyroid oncosuppressor multiple endocrine neoplasia type 1(MEN1), while MEN1 silencing increases YAP1 expression. Treatment of patient-derived PAds-primary cell cultures and Human embryonic kidney 293A (HEK293A) cells expressing the calcium-sensing receptor (CASR) with the CASR agonist R568 induces YAP1 nuclear accumulation. This effect was prevented by the incubation of the cells with RhoA/Rho-associated coiled-coil-containing protein kinase (ROCK) inhibitors Y27632 and H1152. Lastly, CASR activation increased the expression of the YAP1 gene targets CYR61, CTGF, and WNT5A, and this effect was blunted by YAP1 silencing. Concluding, here we provide preliminary evidence of the involvement of the Hippo pathway in human tumor parathyroid cells and of the existence of a CASR-ROCK-YAP1 axis. We propose a tumor suppressor role for YAP1 and LATS1/2 in parathyroid tumors.
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12
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Leach K, Hannan FM, Josephs TM, Keller AN, Møller TC, Ward DT, Kallay E, Mason RS, Thakker RV, Riccardi D, Conigrave AD, Bräuner-Osborne H. International Union of Basic and Clinical Pharmacology. CVIII. Calcium-Sensing Receptor Nomenclature, Pharmacology, and Function. Pharmacol Rev 2020; 72:558-604. [PMID: 32467152 PMCID: PMC7116503 DOI: 10.1124/pr.119.018531] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The calcium-sensing receptor (CaSR) is a class C G protein-coupled receptor that responds to multiple endogenous agonists and allosteric modulators, including divalent and trivalent cations, L-amino acids, γ-glutamyl peptides, polyamines, polycationic peptides, and protons. The CaSR plays a critical role in extracellular calcium (Ca2+ o) homeostasis, as demonstrated by the many naturally occurring mutations in the CaSR or its signaling partners that cause Ca2+ o homeostasis disorders. However, CaSR tissue expression in mammals is broad and includes tissues unrelated to Ca2+ o homeostasis, in which it, for example, regulates the secretion of digestive hormones, airway constriction, cardiovascular effects, cellular differentiation, and proliferation. Thus, although the CaSR is targeted clinically by the positive allosteric modulators (PAMs) cinacalcet, evocalcet, and etelcalcetide in hyperparathyroidism, it is also a putative therapeutic target in diabetes, asthma, cardiovascular disease, and cancer. The CaSR is somewhat unique in possessing multiple ligand binding sites, including at least five putative sites for the "orthosteric" agonist Ca2+ o, an allosteric site for endogenous L-amino acids, two further allosteric sites for small molecules and the peptide PAM, etelcalcetide, and additional sites for other cations and anions. The CaSR is promiscuous in its G protein-coupling preferences, and signals via Gq/11, Gi/o, potentially G12/13, and even Gs in some cell types. Not surprisingly, the CaSR is subject to biased agonism, in which distinct ligands preferentially stimulate a subset of the CaSR's possible signaling responses, to the exclusion of others. The CaSR thus serves as a model receptor to study natural bias and allostery. SIGNIFICANCE STATEMENT: The calcium-sensing receptor (CaSR) is a complex G protein-coupled receptor that possesses multiple orthosteric and allosteric binding sites, is subject to biased signaling via several different G proteins, and has numerous (patho)physiological roles. Understanding the complexities of CaSR structure, function, and biology will aid future drug discovery efforts seeking to target this receptor for a diversity of diseases. This review summarizes what is known to date regarding key structural, pharmacological, and physiological features of the CaSR.
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Affiliation(s)
- Katie Leach
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Fadil M Hannan
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Tracy M Josephs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Andrew N Keller
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Thor C Møller
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Donald T Ward
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Enikö Kallay
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Rebecca S Mason
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Rajesh V Thakker
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Daniela Riccardi
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Arthur D Conigrave
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Hans Bräuner-Osborne
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
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Tutunea-Fatan E, Lee JC, Denker BM, Gunaratnam L. Heterotrimeric Gα 12/13 proteins in kidney injury and disease. Am J Physiol Renal Physiol 2020; 318:F660-F672. [PMID: 31984793 DOI: 10.1152/ajprenal.00453.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Gα12 and Gα13 are ubiquitous members of the heterotrimeric guanine nucleotide-binding protein (G protein) family that play central and integrative roles in the regulation of signal transduction cascades within various cell types in the kidney. Gα12/Gα13 proteins enable the kidney to adapt to an ever-changing environment by transducing stimuli from cell surface receptors and accessory proteins to effector systems. Therefore, perturbations in Gα12/Gα13 levels or their activity can contribute to the pathogenesis of various renal diseases, including renal cancer. This review will highlight and discuss the complex and expanding roles of Gα12/Gα13 proteins on distinct renal pathologies, with emphasis on more recently reported findings. Deciphering how the different Gα12/Gα13 interaction networks participate in the onset and development of renal diseases may lead to the discovery of new therapeutic strategies.
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Affiliation(s)
- Elena Tutunea-Fatan
- Matthew Mailing Centre for Translational Transplant Studies, Lawson Health Research Institute, London, Ontario, Canada
| | - Jasper C Lee
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Bradley M Denker
- Beth Israel Deaconess Medical Center and Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Lakshman Gunaratnam
- Matthew Mailing Centre for Translational Transplant Studies, Lawson Health Research Institute, London, Ontario, Canada.,Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada.,Division of Nephrology, Department of Medicine, University of Western Ontario, London, Ontario, Canada
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14
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Sensing Extracellular Calcium - An Insight into the Structure and Function of the Calcium-Sensing Receptor (CaSR). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:1031-1063. [PMID: 31646544 DOI: 10.1007/978-3-030-12457-1_41] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The calcium-sensing receptor (CaSR) is a G protein-coupled receptor that plays a key role in calcium homeostasis, by sensing free calcium levels in blood and regulating parathyroid hormone secretion in response. The CaSR is highly expressed in parathyroid gland and kidney where its role is well characterised, but also in other tissues where its function remains to be determined. The CaSR can be activated by a variety of endogenous ligands, as well as by synthetic modulators such as Cinacalcet, used in the clinic to treat secondary hyperparathyroidism in patients with chronic kidney disease. The CaSR couples to multiple G proteins, in a tissue-specific manner, activating several signalling pathways and thus regulating diverse intracellular events. The multifaceted nature of this receptor makes it a valuable therapeutic target for calciotropic and non-calciotropic diseases. It is therefore essential to understand the complexity behind the pharmacology, trafficking, and signalling characteristics of this receptor. This review provides an overview of the latest knowledge about the CaSR and discusses future hot topics in this field.
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15
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van der Vorst EPC, Peters LJF, Müller M, Gencer S, Yan Y, Weber C, Döring Y. G-Protein Coupled Receptor Targeting on Myeloid Cells in Atherosclerosis. Front Pharmacol 2019; 10:531. [PMID: 31191301 PMCID: PMC6540917 DOI: 10.3389/fphar.2019.00531] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 04/29/2019] [Indexed: 12/11/2022] Open
Abstract
Atherosclerosis, the underlying cause of the majority of cardiovascular diseases (CVDs), is a lipid-driven, inflammatory disease of the large arteries. Gold standard therapy with statins and the more recently developed proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have improved health conditions among CVD patients by lowering low density lipoprotein (LDL) cholesterol. Nevertheless, a substantial part of these patients is still suffering and it seems that 'just' lipid lowering is insufficient. The results of the Canakinumab Anti-inflammatory Thrombosis Outcome Study (CANTOS) have now proven that inflammation is a key driver of atherosclerosis and that targeting inflammation improves CVD outcomes. Therefore, the identification of novel drug targets and development of novel therapeutics that block atherosclerosis-specific inflammatory pathways have to be promoted. The inflammatory processes in atherosclerosis are facilitated by a network of immune cells and their subsequent responses. Cell networking is orchestrated by various (inflammatory) mediators which interact, bind and induce signaling. Over the last years, G-protein coupled receptors (GPCRs) emerged as important players in recognizing these mediators, because of their diverse functions in steady state but also and specifically during chronic inflammatory processes - such as atherosclerosis. In this review, we will therefore highlight a selection of these receptors or receptor sub-families mainly expressed on myeloid cells and their role in atherosclerosis. More specifically, we will focus on chemokine receptors, both classical and atypical, formyl-peptide receptors, the chemerin receptor 23 and the calcium-sensing receptor. When information is available, we will also describe the consequences of their targeting which may hold promising options for future treatment of CVD.
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Affiliation(s)
- Emiel P. C. van der Vorst
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-University Munich, Munich, Germany
- Department of Pathology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, Netherlands
- Institute for Molecular Cardiovascular Research/Interdisciplinary Center for Clinical Research, RWTH Aachen University, Aachen, Germany
- Munich Heart Alliance, German Centre for Cardiovascular Research, Munich, Germany
| | - Linsey J. F. Peters
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Madeleine Müller
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Selin Gencer
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Yi Yan
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Christian Weber
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-University Munich, Munich, Germany
- Munich Heart Alliance, German Centre for Cardiovascular Research, Munich, Germany
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Yvonne Döring
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-University Munich, Munich, Germany
- Munich Heart Alliance, German Centre for Cardiovascular Research, Munich, Germany
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16
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Tyrosine nitration of mitochondrial proteins during myocardial ischemia and reperfusion. J Physiol Biochem 2019; 75:217-227. [PMID: 31115776 DOI: 10.1007/s13105-019-00683-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 04/23/2019] [Indexed: 12/28/2022]
Abstract
Myocardial ischemia reperfusion is associated with mitochondrial dysfunction and increased formation of reactive oxygen/nitrogen species. The main purpose of this study was to assess the role of tyrosine nitration of mitochondrial proteins in postischemic contractile dysfunction known as myocardial stunning. Isolated Langendorff-perfused rat hearts were subjected to 20-min global ischemia followed by 30-min reperfusion. The reperfused hearts showed marked decline in left ventricular developed pressure, maximal rate of contraction (+dP/dt), and maximal rate of relaxation (-dP/dt). Immunofluorescence and ELISA assays demonstrated enhanced protein tyrosine nitration in reperfused hearts. Using two-dimensional gel electrophoresis and MALDI-TOF/TOF mass spectrometry, eight mitochondrial proteins were identified to be nitrated after ischemia reperfusion. These proteins are crucial in mitochondrial electron transport, fatty acid oxidation, tricarboxylic acid cycle, ATP synthesis, and control of high-energy phosphates. The proteome data also indicated reduced abundance in several of nitrated proteins. The results suggest that these changes may contribute to inhibition of aconitase activity but are unlikely to affect electron transport chain activity. Whether tyrosine nitration of mitochondrial proteins can be considered the contributing factor of postischemic contractile dysfunction remains to be explored.
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Seyedabadi M, Ghahremani MH, Albert PR. Biased signaling of G protein coupled receptors (GPCRs): Molecular determinants of GPCR/transducer selectivity and therapeutic potential. Pharmacol Ther 2019; 200:148-178. [PMID: 31075355 DOI: 10.1016/j.pharmthera.2019.05.006] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 04/26/2019] [Indexed: 02/07/2023]
Abstract
G protein coupled receptors (GPCRs) convey signals across membranes via interaction with G proteins. Originally, an individual GPCR was thought to signal through one G protein family, comprising cognate G proteins that mediate canonical receptor signaling. However, several deviations from canonical signaling pathways for GPCRs have been described. It is now clear that GPCRs can engage with multiple G proteins and the line between cognate and non-cognate signaling is increasingly blurred. Furthermore, GPCRs couple to non-G protein transducers, including β-arrestins or other scaffold proteins, to initiate additional signaling cascades. Receptor/transducer selectivity is dictated by agonist-induced receptor conformations as well as by collateral factors. In particular, ligands stabilize distinct receptor conformations to preferentially activate certain pathways, designated 'biased signaling'. In this regard, receptor sequence alignment and mutagenesis have helped to identify key receptor domains for receptor/transducer specificity. Furthermore, molecular structures of GPCRs bound to different ligands or transducers have provided detailed insights into mechanisms of coupling selectivity. However, receptor dimerization, compartmentalization, and trafficking, receptor-transducer-effector stoichiometry, and ligand residence and exposure times can each affect GPCR coupling. Extrinsic factors including cell type or assay conditions can also influence receptor signaling. Understanding these factors may lead to the development of improved biased ligands with the potential to enhance therapeutic benefit, while minimizing adverse effects. In this review, evidence for ligand-specific GPCR signaling toward different transducers or pathways is elaborated. Furthermore, molecular determinants of biased signaling toward these pathways and relevant examples of the potential clinical benefits and pitfalls of biased ligands are discussed.
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Affiliation(s)
- Mohammad Seyedabadi
- Department of Pharmacology, School of Medicine, Bushehr University of Medical Sciences, Iran; Education Development Center, Bushehr University of Medical Sciences, Iran
| | | | - Paul R Albert
- Ottawa Hospital Research Institute, Neuroscience, University of Ottawa, Canada.
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Antagonism of Ca 2+-sensing receptors by NPS 2143 is transiently masked by p38 activation in mouse brain bEND.3 endothelial cells. Naunyn Schmiedebergs Arch Pharmacol 2019; 392:823-832. [PMID: 30826858 DOI: 10.1007/s00210-019-01637-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 02/22/2019] [Indexed: 10/27/2022]
Abstract
Ca2+-sensing receptors (CaSR) are G protein-coupled receptors which are activated by a rise in extracellular Ca2+. CaSR activation has been known to inhibit parathyroid hormone release and stimulate calcitonin release from parathyroid glands and thyroid parafollicular C cells, respectively. The roles of CaSR in other cell types including endothelial cells (EC) are much less understood. In this work, we demonstrated protein and functional expression of CaSR in mouse cerebral EC (bEND.3). Unexpectedly, CaSR response (high Ca2+-elicited cytosolic [Ca2+] elevation) was unaffected by edelfosine or U73122 but strongly suppressed by SK&F 96365, ruthenium red, and 2-aminoethoxydiphenyl borate (2-APB), suggesting involvement of TRPV and TRPC channels but not Gq-phospholipase C. Acute application of NPS2143, a negative allosteric modulator of CaSR, suppressed CaSR response. However, a 40-min NPS2143 pre-treatment surprisingly enhanced CaSR response. After 4-24 h of application, this enhancement faded away and suppression of CaSR response was observed again. Similar results were obtained when La3+ and Sr2+ were used as CaSR agonists. The transient NPS 2143 enhancement effect was abolished by SB203580, a p38 inhibitor. Consistently, NPS 2143 triggered a transient p38 activation. Taken together, results suggest that in bEND.3 cells, NPS 2143 caused acute suppression of CaSR response, but then elicited a transient enhancement of CaSR response in a p38-dependent manner. NPS 2143 effects on CaSR in bEND.3 cells therefore depended on drug exposure time. These findings warrant cautious use of this agent as a CaSR modulator and potential cardiovascular drug.
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Molecular Mechanisms of Prophase I Meiotic Arrest Maintenance and Meiotic Resumption in Mammalian Oocytes. Reprod Sci 2018; 26:1519-1537. [DOI: 10.1177/1933719118765974] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Mechanisms of meiotic prophase I arrest maintenance (germinal vesicle [GV] stage) and meiotic resumption (germinal vesicle breakdown [GVBD] stage) in mammalian oocytes seem to be very complicated. These processes are regulated via multiple molecular cascades at transcriptional, translational, and posttranslational levels, and many of them are interrelated. There are many molecular cascades of meiosis maintaining and meiotic resumption in oocyte which are orchestrated by multiple molecules produced by pituitary gland and follicular cells. Furthermore, many of these molecular cascades are duplicated, thus ensuring the stability of the entire system. Understanding mechanisms of oocyte maturation is essential to assess the oocyte status, develop effective protocols of oocyte in vitro maturation, and design novel contraceptive drugs. Mechanisms of meiotic arrest maintenance at prophase I and meiotic resumption in mammalian oocytes are covered in the present article.
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Gorvin CM, Rogers A, Hastoy B, Tarasov AI, Frost M, Sposini S, Inoue A, Whyte MP, Rorsman P, Hanyaloglu AC, Breitwieser GE, Thakker RV. AP2σ Mutations Impair Calcium-Sensing Receptor Trafficking and Signaling, and Show an Endosomal Pathway to Spatially Direct G-Protein Selectivity. Cell Rep 2018; 22:1054-1066. [PMID: 29420171 PMCID: PMC5792449 DOI: 10.1016/j.celrep.2017.12.089] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 11/30/2017] [Accepted: 12/22/2017] [Indexed: 12/29/2022] Open
Abstract
Spatial control of G-protein-coupled receptor (GPCR) signaling, which is used by cells to translate complex information into distinct downstream responses, is achieved by using plasma membrane (PM) and endocytic-derived signaling pathways. The roles of the endomembrane in regulating such pleiotropic signaling via multiple G-protein pathways remain unknown. Here, we investigated the effects of disease-causing mutations of the adaptor protein-2 σ subunit (AP2σ) on signaling by the class C GPCR calcium-sensing receptor (CaSR). These AP2σ mutations increase CaSR PM expression yet paradoxically reduce CaSR signaling. Hypercalcemia-associated AP2σ mutations reduced CaSR signaling via Gαq/11 and Gαi/o pathways. The mutations also delayed CaSR internalization due to prolonged residency time of CaSR in clathrin structures that impaired or abolished endosomal signaling, which was predominantly mediated by Gαq/11. Thus, compartmental bias for CaSR-mediated Gαq/11 endomembrane signaling provides a mechanistic basis for multidimensional GPCR signaling. Disease-causing AP2σ mutants impair Gαq/11 and Gαi/o signaling by CaSR, a class C GPCR AP2σ mutants impair trafficking of the CaSR The CaSR can signal by a sustained endosomal pathway CaSR differentially uses Gαq/11 and Gαi/o for cell-surface and endosomal signaling
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Affiliation(s)
- Caroline M Gorvin
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK; Centre for Endocrinology, Diabetes and Metabolism (CEDAM), Birmingham Health Partners, Birmingham, UK
| | - Angela Rogers
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Benoit Hastoy
- Diabetes Research Laboratory, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Andrei I Tarasov
- Diabetes Research Laboratory, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Morten Frost
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Silvia Sposini
- Institute of Reproductive and Developmental Biology, Faculty of Medicine, Imperial College London, London, UK
| | - Asuka Inoue
- Laboratory of Molecular and Cellular Biochemistry, Tohoku University, Sendai, Japan; Japan Science and Technology (JST) Agency, Precursory Research for Embryonic Science and Technology (PRESTO), Kawaguchi, Japan
| | - Michael P Whyte
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children, St. Louis, MO, USA
| | - Patrik Rorsman
- Diabetes Research Laboratory, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Aylin C Hanyaloglu
- Institute of Reproductive and Developmental Biology, Faculty of Medicine, Imperial College London, London, UK
| | - Gerda E Breitwieser
- Geisinger Clinic, Weis Center for Research, Department of Functional and Molecular Genomics, Danville, PA, USA
| | - Rajesh V Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
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21
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Zhang C, Miller CL, Gorkhali R, Zou J, Huang K, Brown EM, Yang JJ. Molecular Basis of the Extracellular Ligands Mediated Signaling by the Calcium Sensing Receptor. Front Physiol 2016; 7:441. [PMID: 27746744 PMCID: PMC5043022 DOI: 10.3389/fphys.2016.00441] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 09/16/2016] [Indexed: 12/20/2022] Open
Abstract
Ca2+-sensing receptors (CaSRs) play a central role in regulating extracellular calcium concentration ([Ca2+]o) homeostasis and many (patho)physiological processes in multiple organs. This regulation is orchestrated by a cooperative response to extracellular stimuli such as small changes in Ca2+, Mg2+, amino acids, and other ligands. In addition, CaSR is a pleiotropic receptor regulating several intracellular signaling pathways, including calcium mobilization and intracellular calcium oscillation. Nearly 200 mutations and polymorphisms have been found in CaSR in relation to a variety of human disorders associated with abnormal Ca2+ homeostasis. In this review, we summarize efforts directed at identifying binding sites for calcium and amino acids. Both homotropic cooperativity among multiple calcium binding sites and heterotropic cooperativity between calcium and amino acid were revealed using computational modeling, predictions, and site-directed mutagenesis coupled with functional assays. The hinge region of the bilobed Venus flytrap (VFT) domain of CaSR plays a pivotal role in coordinating multiple extracellular stimuli, leading to cooperative responses from the receptor. We further highlight the extensive number of disease-associated mutations that have also been shown to affect CaSR's cooperative action via several types of mechanisms. These results provide insights into the molecular bases of the structure and functional cooperativity of this receptor and other members of family C of the G protein-coupled receptors (cGPCRs) in health and disease states, and may assist in the prospective development of novel receptor-based therapeutics.
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Affiliation(s)
- Chen Zhang
- Department of Chemistry, Georgia State University Atlanta, GA, USA
| | | | - Rakshya Gorkhali
- Department of Chemistry, Georgia State University Atlanta, GA, USA
| | - Juan Zou
- Department of Chemistry, Georgia State University Atlanta, GA, USA
| | - Kenneth Huang
- Department of Chemistry, Georgia State University Atlanta, GA, USA
| | - Edward M Brown
- Center for Diagnostics and Therapeutics, Georgia State UniversityAtlanta, GA, USA; Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's HospitalBoston, MA, USA
| | - Jenny J Yang
- Department of Chemistry, Georgia State University Atlanta, GA, USA
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22
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Santa Maria C, Cheng Z, Li A, Wang J, Shoback D, Tu CL, Chang W. Interplay between CaSR and PTH1R signaling in skeletal development and osteoanabolism. Semin Cell Dev Biol 2016; 49:11-23. [PMID: 26688334 PMCID: PMC4761456 DOI: 10.1016/j.semcdb.2015.12.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 12/05/2015] [Indexed: 12/01/2022]
Abstract
Parathyroid hormone (PTH)-related peptide (PTHrP) controls the pace of pre- and post-natal growth plate development by activating the PTH1R in chondrocytes, while PTH maintains mineral and skeletal homeostasis by modulating calciotropic activities in kidneys, gut, and bone. The extracellular calcium-sensing receptor (CaSR) is a member of family C, G protein-coupled receptor, which regulates mineral and skeletal homeostasis by controlling PTH secretion in parathyroid glands and Ca(2+) excretion in kidneys. Recent studies showed the expression of CaSR in chondrocytes, osteoblasts, and osteoclasts and confirmed its non-redundant roles in modulating the recruitment, proliferation, survival, and differentiation of the cells. This review emphasizes the actions of CaSR and PTH1R signaling responses in cartilage and bone and discusses how these two signaling cascades interact to control growth plate development and maintain skeletal metabolism in physiological and pathological conditions. Lastly, novel therapeutic regimens that exploit interrelationship between the CaSR and PTH1R are proposed to produce more robust osteoanabolism.
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Affiliation(s)
- Christian Santa Maria
- Endocrine Research Unit, University of California, San Francisco, Veterans Affairs Medical Center, San Francisco, CA, USA
| | - Zhiqiang Cheng
- Endocrine Research Unit, University of California, San Francisco, Veterans Affairs Medical Center, San Francisco, CA, USA
| | - Alfred Li
- Endocrine Research Unit, University of California, San Francisco, Veterans Affairs Medical Center, San Francisco, CA, USA
| | - Jiali Wang
- Endocrine Research Unit, University of California, San Francisco, Veterans Affairs Medical Center, San Francisco, CA, USA
| | - Dolores Shoback
- Endocrine Research Unit, University of California, San Francisco, Veterans Affairs Medical Center, San Francisco, CA, USA
| | - Chia-Ling Tu
- Endocrine Research Unit, University of California, San Francisco, Veterans Affairs Medical Center, San Francisco, CA, USA
| | - Wenhan Chang
- Endocrine Research Unit, University of California, San Francisco, Veterans Affairs Medical Center, San Francisco, CA, USA.
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23
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Liu C, Wu GQ, Fu XW, Mo XH, Zhao LH, Hu HM, Zhu SE, Hou YP. The Extracellular Calcium-Sensing Receptor (CASR) Regulates Gonadotropins-Induced Meiotic Maturation of Porcine Oocytes. Biol Reprod 2015; 93:131. [PMID: 26490840 DOI: 10.1095/biolreprod.115.128579] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 10/14/2015] [Indexed: 12/16/2022] Open
Abstract
Gonadotropins and epidermal growth factor (EGF) play crucial roles in promoting oocyte maturation. The regulatory network downstream of these key factors is not well understood. The present study was designed to investigate the role of the calcium-sensing receptor (CASR) in porcine oocyte in vitro maturation. CASR expression was up-regulated in oocytes matured in gonadotropin-containing medium. Cortical distribution of CASR was enhanced with gonadotropins but not EGF. Supplementation of a CASR agonist (NPS R-568) in the gonadotropin (FSH and/or LH)-containing maturation medium significantly enhanced oocyte nuclear maturation. Addition of NPS2390, a CASR antagonist, compromised oocyte nuclear maturation. Furthermore, increased cortical distribution and decreased expression of CASR was observed after the NPS R-568 treatment. Oocytes treated with NPS R-568 had higher concentration of CYCLIN B1, decreased reactive oxygen species, and increased glutathione levels, indicative of advanced cytoplasmic maturation. In contrast, NPS2390 treatment compromised oocyte cytoplasmic maturation. A higher blastocyst formation rate after parthenogenetic activation was observed when oocytes were matured in the presence of the CASR agonist, NPS R-568. MAPK3/1 phosphorylation was increased during in vitro maturation and after NPS R-568 treatment, and decreased following CASR antagonist supplementation. Taken together, our data showed that the CASR is a gonadotropin-regulated factor that promotes porcine oocyte maturation in a MAPK-dependent manner.
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Affiliation(s)
- Cong Liu
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Guo-Quan Wu
- Yunnan Animal Science and Veterinary Institute, Kunming, Yunnan, China
| | - Xiang-Wei Fu
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Xian-Hong Mo
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Li-Hong Zhao
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Hong-Mei Hu
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Shi-En Zhu
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Yun-Peng Hou
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
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24
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Biased signalling: the instinctive skill of the cell in the selection of appropriate signalling pathways. Biochem J 2015; 470:155-67. [DOI: 10.1042/bj20150358] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
GPCRs (G-protein-coupled receptors) are members of a family of proteins which are generally regarded as the largest group of therapeutic drug targets. Ligands of GPCRs do not usually activate all cellular signalling pathways linked to a particular seven-transmembrane receptor in a uniform manner. The fundamental idea behind this concept is that each ligand has its own ability, while interacting with the receptor, to activate different signalling pathways (or a particular set of signalling pathways) and it is this concept which is known as biased signalling. The importance of biased signalling is that it may selectively activate biological responses to favour therapeutically beneficial signalling pathways and to avoid adverse effects. There are two levels of biased signalling. First, bias can arise from the ability of GPCRs to couple to a subset of the available G-protein subtypes: Gαs, Gαq/11, Gαi/o or Gα12/13. These subtypes produce the diverse effects of GPCRs by targeting different effectors. Secondly, biased GPCRs may differentially activate G-proteins or β-arrestins. β-Arrestins are ubiquitously expressed and function to terminate or inhibit classic G-protein signalling and initiate distinct β-arrestin-mediated signalling processes. The interplay of G-protein and β-arrestin signalling largely determines the cellular consequences of the administration of GPCR-targeted drugs. In the present review, we highlight the particular functionalities of biased signalling and discuss its biological effects subsequent to GPCR activation. We consider that biased signalling is potentially allowing a choice between signalling through ‘beneficial’ pathways and the avoidance of ‘harmful’ ones.
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25
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Vignaux G, Besnard S, Denise P, Elefteriou F. The Vestibular System: A Newly Identified Regulator of Bone Homeostasis Acting Through the Sympathetic Nervous System. Curr Osteoporos Rep 2015; 13:198-205. [PMID: 26017583 DOI: 10.1007/s11914-015-0271-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The vestibular system is a small bilateral structure located in the inner ear, known as the organ of balance and spatial orientation. It senses head orientation and motion, as well as body motion in the three dimensions of our environment. It is also involved in non-motor functions such as postural control of blood pressure. These regulations are mediated via anatomical projections from vestibular nuclei to brainstem autonomic centers and are involved in the maintenance of cardiovascular function via sympathetic nerves. Age-associated dysfunction of the vestibular organ contributes to an increased incidence of falls, whereas muscle atrophy, reduced physical activity, cellular aging, and gonadal deficiency contribute to bone loss. Recent studies in rodents suggest that vestibular dysfunction might also alter bone remodeling and mass more directly, by affecting the outflow of sympathetic nervous signals to the skeleton and other tissues. This review will summarize the findings supporting the influence of vestibular signals on bone homeostasis, and the potential clinical relevance of these findings.
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Affiliation(s)
- G Vignaux
- Department of Medicine, Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, 1235 Medical Research Building IV, 2215B Garland Avenue, Nashville, TN, 37232-0575, USA
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26
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Leach K, Sexton PM, Christopoulos A, Conigrave AD. Engendering biased signalling from the calcium-sensing receptor for the pharmacotherapy of diverse disorders. Br J Pharmacol 2014; 171:1142-55. [PMID: 24111791 DOI: 10.1111/bph.12420] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 08/22/2013] [Accepted: 08/26/2013] [Indexed: 12/14/2022] Open
Abstract
The human calcium-sensing receptor (CaSR) is widely expressed in the body, where its activity is regulated by multiple orthosteric and endogenous allosteric ligands. Each ligand stabilizes a unique subset of conformational states, which enables the CaSR to couple to distinct intracellular signalling pathways depending on the extracellular milieu in which it is bathed. Differential signalling arising from distinct receptor conformations favoured by each ligand is referred to as biased signalling. The outcome of CaSR activation also depends on the cell type in which it is expressed. Thus, the same ligand may activate diverse pathways in distinct cell types. Given that the CaSR is implicated in numerous physiological and pathophysiological processes, it is an ideal target for biased ligands that could be rationally designed to selectively regulate desired signalling pathways in preferred cell types.
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Affiliation(s)
- K Leach
- Pharmaceutical Sciences, Monash University, Melbourne, Vic., Australia
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27
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Desai AJ, Roberts DJ, Richards GO, Skerry TM. Role of receptor activity modifying protein 1 in function of the calcium sensing receptor in the human TT thyroid carcinoma cell line. PLoS One 2014; 9:e85237. [PMID: 24454825 PMCID: PMC3890319 DOI: 10.1371/journal.pone.0085237] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 12/02/2013] [Indexed: 12/15/2022] Open
Abstract
The Calcium Sensing Receptor (CaSR) plays a role in calcium homeostasis by sensing minute changes in serum Ca(2+) and modulating secretion of calciotropic hormones. It has been shown in transfected cells that accessory proteins known as Receptor Activity Modifying Proteins (RAMPs), specifically RAMPs 1 and 3, are required for cell-surface trafficking of the CaSR. These effects have only been demonstrated in transfected cells, so their physiological relevance is unclear. Here we explored CaSR/RAMP interactions in detail, and showed that in thyroid human carcinoma cells, RAMP1 is required for trafficking of the CaSR. Furthermore, we show that normal RAMP1 function is required for intracellular responses to ligands. Specifically, to confirm earlier studies with tagged constructs, and to provide the additional benefit of quantitative stoichiometric analysis, we used fluorescence resonance energy transfer to show equal abilities of RAMP1 and 3 to chaperone CaSR to the cell surface, though RAMP3 interacted more efficiently with the receptor. Furthermore, a higher fraction of RAMP3 than RAMP1 was observed in CaSR-complexes on the cell-surface, suggesting different ratios of RAMPs to CaSR. In order to determine relevance of these findings in an endogenous expression system we assessed the effect of RAMP1 siRNA knock-down in medullary thyroid carcinoma TT cells, (which express RAMP1, but not RAMP3 constitutively) and measured a significant 50% attenuation of signalling in response to CaSR ligands Cinacalcet and neomycin. Blockade of RAMP1 using specific antibodies induced a concentration-dependent reduction in CaSR-mediated signalling in response to Cinacalcet in TT cells, suggesting a novel functional role for RAMP1 in regulation of CaSR signalling in addition to its known role in receptor trafficking. These data provide evidence that RAMPs traffic the CaSR as higher-level oligomers and play a role in CaSR signalling even after cell surface localisation has occurred.
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Affiliation(s)
- Aditya J. Desai
- The Mellanby Centre for Bone Research, Department of Human Metabolism, University of Sheffield, Sheffield, United Kingdom
| | - David J. Roberts
- The Mellanby Centre for Bone Research, Department of Human Metabolism, University of Sheffield, Sheffield, United Kingdom
| | - Gareth O. Richards
- The Mellanby Centre for Bone Research, Department of Human Metabolism, University of Sheffield, Sheffield, United Kingdom
| | - Timothy M. Skerry
- The Mellanby Centre for Bone Research, Department of Human Metabolism, University of Sheffield, Sheffield, United Kingdom
- * E-mail:
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28
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Kopic S, Geibel JP. Gastric acid, calcium absorption, and their impact on bone health. Physiol Rev 2013; 93:189-268. [PMID: 23303909 DOI: 10.1152/physrev.00015.2012] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Calcium balance is essential for a multitude of physiological processes, ranging from cell signaling to maintenance of bone health. Adequate intestinal absorption of calcium is a major factor for maintaining systemic calcium homeostasis. Recent observations indicate that a reduction of gastric acidity may impair effective calcium uptake through the intestine. This article reviews the physiology of gastric acid secretion, intestinal calcium absorption, and their respective neuroendocrine regulation and explores the physiological basis of a potential link between these individual systems.
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Affiliation(s)
- Sascha Kopic
- Department of Surgery and Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut, USA
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29
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Thomsen ARB, Worm J, Jacobsen SE, Stahlhut M, Latta M, Bräuner-Osborne H. Strontium is a biased agonist of the calcium-sensing receptor in rat medullary thyroid carcinoma 6-23 cells. J Pharmacol Exp Ther 2012; 343:638-49. [PMID: 22942242 PMCID: PMC11047797 DOI: 10.1124/jpet.112.197210] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 08/30/2012] [Indexed: 09/23/2023] Open
Abstract
The calcium-sensing receptor (CaSR)-specific allosteric modulator cinacalcet has revolutionized the treatment of secondary hyperparathyroidism in patients with chronic kidney disease. However, its application is limited to patients with end-stage renal disease because of hypocalcemic side effects presumably caused by CaSR-mediated calcitonin secretion from thyroid parafollicular C-cells. These hypocalcemic side effects might be dampened by compounds that bias the signaling of CaSR, causing similar therapeutic effects as cinacalcet without stimulating calcitonin secretion. Because biased signaling of CaSR is poorly understood, the objective of the present study was to investigate biased signaling of CaSR by using rat medullary thyroid carcinoma 6-23 cells as a model of thyroid parafollicular C-cells. By doing concentration-response experiments we focused on the ability of two well known CaSR agonists, calcium and strontium, to activate six different signaling entities: G(q/11) signaling, G(i/o) signaling, G(s) signaling, extracellular signal-regulated kinases 1 and 2 (ERK1/2) signaling, intracellular calcium ([Ca(2+)](i)) mobilization, and calcitonin secretion. The experiments showed that strontium biases CaSR signaling toward ERK1/2 signaling and possibly another pathway independent of G(q/11) signaling and [Ca(2+)](i) mobilization. It is noteworthy that the potency of strontium-stimulated calcitonin secretion was elevated compared with calcium. Combining these results with experiments investigating signaling pathway components involved in calcitonin secretion, we found that the enhanced potency of strontium-mediated calcitonin secretion was caused by a different signaling pattern than that produced by calcium. Together, our results suggest that calcitonin secretion can be affected by CaSR-stimulated signaling bias, which may be used to develop novel drugs for the treatment of secondary hyperparathyroidism.
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Affiliation(s)
- Alex Rojas Bie Thomsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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30
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Lusche DF, Wessels D, Scherer A, Daniels K, Kuhl S, Soll DR. The IplA Ca2+ channel of Dictyostelium discoideum is necessary for chemotaxis mediated through Ca2+, but not through cAMP, and has a fundamental role in natural aggregation. J Cell Sci 2012; 125:1770-83. [PMID: 22375061 DOI: 10.1242/jcs.098301] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
During aggregation of Dictyostelium discoideum, nondissipating, symmetrical, outwardly moving waves of cAMP direct cells towards aggregation centers. It has been assumed that the spatial and temporal characteristics of the front and back of each cAMP wave regulate both chemokinesis and chemotaxis. However, during the period preceding aggregation, cells acquire not only the capacity to chemotax in a spatial gradient of cAMP, but also in a spatial gradient of Ca(2+). The null mutant of the putative IplA Ca(2+) channel gene, iplA(-), undergoes normal chemotaxis in spatial gradients of cAMP and normal chemokinetic responses to increasing temporal gradients of cAMP, both generated in vitro. However, iplA(-) cells lose the capacity to undergo chemotaxis in response to a spatial gradient of Ca(2+), suggesting that IplA is either the Ca(2+) chemotaxis receptor or an essential component of the Ca(2+) chemotaxis regulatory pathway. In response to natural chemotactic waves generated by wild-type cells, the chemokinetic response of iplA(-) cells to the temporal dynamics of the cAMP wave is intact, but the capacity to reorient in the direction of the aggregation center at the onset of each wave is lost. These results suggest that transient Ca(2+) gradients formed between cells at the onset of each natural cAMP wave augment reorientation towards the aggregation center. If this hypothesis proves correct, it will provide a more complex contextual framework for interpreting D. discoideum chemotaxis.
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Affiliation(s)
- Daniel F Lusche
- W M Keck Dynamic Image Analysis Facility, Department of Biology, University of Iowa, Iowa City, IA 52242, USA
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31
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Thomsen ARB, Hvidtfeldt M, Bräuner-Osborne H. Biased agonism of the calcium-sensing receptor. Cell Calcium 2012; 51:107-16. [PMID: 22192592 DOI: 10.1016/j.ceca.2011.11.009] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 11/05/2011] [Accepted: 11/24/2011] [Indexed: 02/01/2023]
Abstract
After the discovery of molecules modulating G protein-coupled receptors (GPCRs) that are able to selectively affect one signaling pathway over others for a specific GPCR, thereby "biasing" the signaling, it has become obvious that the original model of GPCRs existing in either an "on" or "off" conformation is too simple. The current explanation for this biased agonism is that GPCRs can adopt multiple active conformations stabilized by different molecules, and that each conformation affects intracellular signaling in a different way. In the present study we sought to investigate biased agonism of the calcium-sensing receptor (CaSR), by looking at 12 well-known orthosteric CaSR agonists in 3 different CaSR signaling pathways: G(q/11) protein, G(i/o) protein, and extracellular signal-regulated kinases 1 and 2 (ERK1/2). Here we show that apart from G(q/11) and G(i/o) signaling, ERK1/2 is activated through recruitment of β-arrestins. Next, by measuring activity of all three signaling pathways we found that barium, spermine, neomycin, and tobramycin act as biased agonist in terms of efficacy and/or potency. Finally, polyamines and aminoglycosides in general were biased in their potencies toward ERK1/2 signaling. In conclusion, the results of this study indicate that several active conformations of CaSR, stabilized by different molecules, exist, which affect intracellular signaling distinctly.
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Affiliation(s)
- Alex Rojas Bie Thomsen
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Fruebjergvej 3, Copenhagen, Denmark
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32
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The adaptor protein 14-3-3 binds to the calcium-sensing receptor and attenuates receptor-mediated Rho kinase signalling. Biochem J 2012; 441:995-1006. [DOI: 10.1042/bj20111277] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A yeast two-hybrid screen performed to identify binding partners of the CaR (calcium-sensing receptor) intracellular tail identified the adaptor protein 14-3-3θ as a novel binding partner that bound to the proximal membrane region important for CaR expression and signalling. The 14-3-3θ protein directly interacted with the CaR tail in pull-down studies and FLAG-tagged CaR co-immunoprecipitated with EGFP (enhanced green fluorescent protein)-tagged 14-3-3θ when co-expressed in HEK (human embryonic kidney)-293 or COS-1 cells. The interaction between the CaR and 14-3-3θ did not require a putative binding site in the membrane-proximal region of the CaR tail and was independent of PKC (protein kinase C) phosphorylation. Confocal microscopy demonstrated co-localization of the CaR and EGFP–14-3-3θ in the ER (endoplasmic reticulum) of HEK-293 cells that stably expressed the CaR (HEK-293/CaR cells), but 14-3-3θ overexpression had no effect on membrane expression of the CaR. Overexpression of 14-3-3θ in HEK-293/CaR cells attenuated CaR-mediated Rho signalling, but had no effect on ERK (extracellular-signal-regulated kinase) 1/2 signalling. Another isoform identified from the library, 14-3-3ζ, exhibited similar behaviour to that of 14-3-3θ with respect to CaR tail binding, cellular co-localization and impact on receptor-mediated signalling. However, unlike 14-3-3θ, this isoform, when overexpressed, significantly reduced CaR plasma membrane expression. Results indicate that 14-3-3 proteins mediate CaR-dependent Rho signalling and may modulate the plasma membrane expression of the CaR.
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33
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Abstract
The calcium-sensing receptor (CaR) is the key controller of extracellular calcium (Ca(2+)(o)) homeostasis via its regulation of parathyroid hormone (PTH) secretion and renal Ca(2+) reabsorption. The CaR-selective calcimimetic drug Cinacalcet stimulates the CaR to suppress PTH secretion in chronic kidney disease and represents the world's first clinically available receptor positive allosteric modulator (PAM). Negative CaR allosteric modulators (NAMs), known as calcilytics, can increase PTH secretion and are being investigated as possible bone anabolic treatments against age-related osteoporosis. Here we address the current state of development and clinical use of a series of positive and negative CaR modulators. In addition, clinical CaR mutations and transgenic mice carrying tissue-specific CaR deletions have provided a novel understanding of the relative functional importance of CaR in both calciotropic tissues and those elsewhere in the body. The development of CaR-selective modulators and signalling reagents have provided us with a more detailed appreciation of how the CaR signals in vivo. Thus, both of these areas of CaR research will be reviewed.
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Affiliation(s)
- Donald T Ward
- Faculty of Life Sciences, The University of ManchesterManchester, UK
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34
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Signaling through the extracellular calcium-sensing receptor (CaSR). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:103-42. [PMID: 22453940 DOI: 10.1007/978-94-007-2888-2_5] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The extracellular calcium ([Formula: see text])-sensing receptor (CaSR) was the first GPCR identified whose principal physiological ligand is an ion, namely extracellular Ca(2+). It maintains the near constancy of [Formula: see text] that complex organisms require to ensure normal cellular function. A wealth of information has accumulated over the past two decades about the CaSR's structure and function, its role in diseases and CaSR-based therapeutics. This review briefly describes the CaSR and key features of its structure and function, then discusses the extracellular signals modulating its activity, provides an overview of the intracellular signaling pathways that it controls, and, finally, briefly describes CaSR signaling both in tissues participating in [Formula: see text] homeostasis as well as those that do not. Factors controlling CaSR signaling include various factors affecting the expression of the CaSR gene as well as modulation of its trafficking to and from the cell surface. The dimeric cell surface CaSR, in turn, links to various heterotrimeric and small molecular weight G proteins to regulate intracellular second messengers, lipid kinases, various protein kinases, and transcription factors that are part of the machinery enabling the receptor to modulate the functions of the wide variety of cells in which it is expressed. CaSR signaling is impacted by its interactions with several binding partners in addition to signaling elements per se (i.e., G proteins), including filamin-A and caveolin-1. These latter two proteins act as scaffolds that bind signaling components and other key cellular elements (e.g., the cytoskeleton). Thus CaSR signaling likely does not take place randomly throughout the cell, but is compartmentalized and organized so as to facilitate the interaction of the receptor with its various signaling pathways.
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35
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Tharmalingam S, Daulat AM, Antflick JE, Ahmed SM, Nemeth EF, Angers S, Conigrave AD, Hampson DR. Calcium-sensing receptor modulates cell adhesion and migration via integrins. J Biol Chem 2011; 286:40922-33. [PMID: 21969374 DOI: 10.1074/jbc.m111.265454] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The calcium-sensing receptor (CaSR) is a family C G protein-coupled receptor that is activated by elevated levels of extracellular divalent cations. The CaSR couples to members of the G(q) family of G proteins, and in the endocrine system this receptor is instrumental in regulating the release of parathyroid hormone from the parathyroid gland and calcitonin from thyroid cells. Here, we demonstrate that in medullary thyroid carcinoma cells, the CaSR promotes cellular adhesion and migration via coupling to members of the integrin family of extracellular matrix-binding proteins. Immunopurification and mass spectrometry, co-immunoprecipitation, and co-localization studies showed that the CaSR and β1-containing integrins are components of a macromolecular protein complex. In fibronectin-based cell adhesion and migration assays, the CaSR-positive allosteric modulator NPS R-568 induced a concentration-dependent increase in cell adhesion and migration; both of these effects were blocked by a specific CaSR-negative allosteric modulator. These effects were mediated by integrins because they were blocked by a peptide inhibitor of integrin binding to fibronectin and β1 knockdown experiments. An analysis of intracellular signaling pathways revealed a key role for CaSR-induced phospholipase C activation and the release of intracellular calcium. These results demonstrate for the first time that an ion-sensing G protein-coupled receptor functionally couples to the integrins and, in conjunction with intracellular calcium release, promotes cellular adhesion and migration in tumor cells. The significance of this interaction is further highlighted by studies implicating the CaSR in cancer metastasis, axonal growth, and stem cell attachment, functions that rely on integrin-mediated cell adhesion.
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Affiliation(s)
- Sujeenthar Tharmalingam
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
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Abstract
Compelling evidence of a cell surface receptor sensitive to extracellular calcium was observed as early as the 1980s and was finally realized in 1993 when the calcium-sensing receptor (CaR) was cloned from bovine parathyroid tissue. Initial studies relating to the CaR focused on its key role in extracellular calcium homeostasis, but as the amount of information about the receptor grew it became evident that it was involved in many biological processes unrelated to calcium homeostasis. The CaR responds to a diverse array of stimuli extending well beyond that merely of calcium, and these stimuli can lead to the initiation of a wide variety of intracellular signaling pathways that in turn are able to regulate a diverse range of biological processes. It has been through the examination of the molecular characteristics of the CaR that we now have an understanding of how this single receptor is able to convert extracellular messages into specific cellular responses. Recent CaR-related reviews have focused on specific aspects of the receptor, generally in the context of the CaR's role in physiology and pathophysiology. This review will provide a comprehensive exploration of the different aspects of the receptor, including its structure, stimuli, signalling, interacting protein partners, and tissue expression patterns, and will relate their impact on the functionality of the CaR from a molecular perspective.
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Affiliation(s)
- Aaron L Magno
- Department of Endocrinology and Diabetes, First Floor, C Block, Sir Charles Gairdner Hospital, Hospital Avenue, Nedlands 6009, Western Australia, Australia
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Tu CL, Chang W, Bikle DD. The calcium-sensing receptor-dependent regulation of cell-cell adhesion and keratinocyte differentiation requires Rho and filamin A. J Invest Dermatol 2011; 131:1119-28. [PMID: 21209619 DOI: 10.1038/jid.2010.414] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Extracellular Ca(2+) (Ca(2+)(o)) functioning through the calcium-sensing receptor (CaR) induces E-cadherin-mediated cell-cell adhesion and cellular signals mediating cell differentiation in epidermal keratinocytes. Previous studies indicate that CaR regulates cell-cell adhesion through Fyn/Src tyrosine kinases. In this study, we investigate whether Rho GTPase is a part of the CaR-mediated signaling cascade regulating cell adhesion and differentiation. Suppressing endogenous Rho A expression by small interfering RNA (siRNA)-mediated gene silencing blocked the Ca(2+)(o)-induced association of Fyn with E-cadherin and suppressed the Ca(2+)(o)-induced tyrosine phosphorylation of β-, γ-, and p120-catenin and formation of intercellular adherens junctions. Rho A silencing also decreased the Ca(2+)(o)-stimulated expression of terminal differentiation markers. Elevating the Ca(2+)(o) level induced interactions among CaR, Rho A, E-cadherin, and the scaffolding protein filamin A at the cell membrane. Inactivation of CaR expression by adenoviral expression of a CaR antisense complementary DNA inhibited Ca(2+)(o)-induced activation of endogenous Rho. Ca(2+)(o) activation of Rho required a direct interaction between CaR and filamin A. Interference of CaR-filamin interaction inhibited Ca(2+)(o)-induced Rho activation and the formation of cell-cell junctions. These results indicate that Rho is a downstream mediator of CaR in the regulation of Ca(2+)(o)-induced E-cadherin-mediated cell-cell adhesion and keratinocyte differentiation.
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Affiliation(s)
- Chia-Ling Tu
- Endocrine Unit, Veteran Affairs Medical Center and University of California, San Francisco, California 94121, USA.
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Kerner J, Lee K, Hoppel CL. Post-translational modifications of mitochondrial outer membrane proteins. Free Radic Res 2010; 45:16-28. [DOI: 10.3109/10715762.2010.515218] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Huang C, Liu S, Miller RT. Role of p115RhoGEF in the regulation of extracellular Ca2+-induced choline kinase activation and prostate cancer cell proliferation. Int J Cancer 2010; 128:2833-42. [DOI: 10.1002/ijc.25633] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 08/03/2010] [Accepted: 08/10/2010] [Indexed: 01/10/2023]
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Mamillapalli R, Wysolmerski J. The calcium-sensing receptor couples to Galpha(s) and regulates PTHrP and ACTH secretion in pituitary cells. J Endocrinol 2010; 204:287-97. [PMID: 20032198 PMCID: PMC3777408 DOI: 10.1677/joe-09-0183] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The calcium-sensing receptor (CaR or CASR as listed in the MGI Database) is a G protein-coupled receptor that binds and signals in response to extracellular calcium and other polycations. It is highly expressed on parathyroid and kidney cells, where it participates in the regulation of systemic calcium homeostasis. It is also expressed on many other cell types and is involved in a wide array of biological functions such as cell growth and differentiation, ion transport, and hormone secretion. It has been described to couple to several different G proteins including Galpha(i/0), Galpha(q/11), and Galpha(12/13). Recently, it has also been shown to stimulate cAMP production by coupling to Galpha(s) in immortalized or malignant breast cells. The CaR is expressed on cells in the anterior pituitary and had previously been described to stimulate cAMP production in these cells. In this report, we examined signaling from the CaR in murine pituitary corticotroph-derived, AtT-20 cells. We found that CaR activation led to the stimulation of cAMP production, and PTH-related protein (PTHrP or PTHLH as listed in the MGI Database) and ACTH secretion from these cells. Furthermore, manipulation of cAMP levels was able to modulate PTHrP and ACTH secretion independent of changes in extracellular calcium. Finally, we demonstrated that the CaR couples to Galpha(s) in AtT-20 cells. Therefore, in pituitary corticotroph-like cells, as in breast cancer cells, the CaR utilizes Galpha(s) and activates cAMP production to stimulate hormone secretion.
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Affiliation(s)
- Ramanaiah Mamillapalli
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, TAC S131, New Haven, Connecticut 06520-8020, USA
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Kim ES, Jeong JB, Kim S, Lee KM, Ko E, Noh DY, Hwang KT, Ha JH, Lee CH, Kim SG, Moon A. The G12 family proteins upregulate matrix metalloproteinase-2 via p53 leading to human breast cell invasion. Breast Cancer Res Treat 2010; 124:49-61. [PMID: 20044778 DOI: 10.1007/s10549-009-0697-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Accepted: 12/16/2009] [Indexed: 12/27/2022]
Abstract
Although mounting evidence suggests a role for G(12) proteins, G(α12) and G(α13), in tumor progression, a direct role of G(12) proteins has not been determined. This study aims to elucidate the molecular mechanism for a tumorigenic and invasive potential of G(α12) and G(α13) in MCF10A human breast epithelial cells. Here, we report, for the first time, that G(α12) and G(α13) induce upregulation of matrix metalloproteinase (MMP)-2 leading to the invasive and migratory phenotypes in MCF10A cells. We further show that p53 is an important transcription factor for induction of MMP-2 transcriptional activation by G(α12/13). G(α12/13)-induced MMP-2 upregulation, invasion, and migration are dependent on the activation of Ras, Rac1, MKK3/6, p38, and Akt. Using human breast tissue samples, we demonstrate that the expression levels of G(α12) and MMP-2 are strongly correlated with the pathogenically diagnosed cancer (P < 0.0001). Moreover, the expression of G(α12) shows a strong correlation with that of MMP-2 in human breast cancer tissues, implicating the in vivo tumorigenic potential of G(α12). Taken together, this study elucidated the role of G(12) proteins in regulating processes for MMP-2 expression and malignant phenotypic conversion of MCF10A human breast epithelial cells, providing a molecular basis for the promoting role of G(α12) and G(α13) in breast cell invasion.
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Affiliation(s)
- Eun-Sook Kim
- College of Pharmacy, Duksung Women's University, Seoul, Korea
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Valenti G, Mira A, Mastrofrancesco L, Lasorsa DR, Ranieri M, Svelto M. Differential Modulation of Intracellular Ca 2+ Responses Associated with Calcium-Sensing Receptor Activation in Renal Collecting Duct Cells. Cell Physiol Biochem 2010; 26:901-12. [DOI: 10.1159/000323999] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/02/2010] [Indexed: 12/26/2022] Open
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Lee M, Choi S, Halldén G, Yo SJ, Schichnes D, Aponte GW. P2Y5 is a G(alpha)i, G(alpha)12/13 G protein-coupled receptor activated by lysophosphatidic acid that reduces intestinal cell adhesion. Am J Physiol Gastrointest Liver Physiol 2009; 297:G641-54. [PMID: 19679818 PMCID: PMC2763810 DOI: 10.1152/ajpgi.00191.2009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
P2Y5 is a G protein-coupled receptor that binds and is activated by lysophosphatidic acid (LPA). We determined that P2Y5 transcript is expressed along the intestinal mucosa and investigated the intracellular pathways induced by P2Y5 activation, which could contribute to LPA effects on intestinal cell adhesion. P2Y5 heterologously expressed in CHO and small intestinal hBRIE 380i cells was activated by LPA resulting in an increase in intracellular calcium ([Ca(2+)](i)) when the cells concurrently expressed G(alpha)(Delta6qi5myr). P2Y5 activation also increased the phosphorylation of ERK1/2 that was sensitive to pertussis toxin. Together these indicate that P2Y5 activation by LPA induces an increase in [Ca(2+)](i) and ERK1/2 phosphorylation through G(alpha)(i). We discovered that P2Y5 was activated by farnesyl pyrophosphate (FPP) without a detectable change in [Ca(2+)](i). The activation of P2Y5 by LPA or FPP induced the activity of a serum response element (SRE)-linked luciferase reporter that was inhibited by the RGS domain of p115RhoGEF, C3 exotoxin, and Y-27632, suggesting the involvement of G(alpha)(12/13), Rho GTPase, and ROCK, respectively. However, only LPA-mediated induction of SRE reporter activity was sensitive to inhibitors targeting p38 MAPK, PI3K, PLC, and PKC. In addition, only LPA transactivated the epidermal growth factor receptor, leading to an induction of ERK1/2 phosphorylation. These observations correlate with our subsequent finding that P2Y5 activation by LPA, and not FPP, reduced intestinal cell adhesion. This study elucidates a mechanism whereby LPA can act as a luminal and/or serosal cue to alter mucosal integrity.
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Affiliation(s)
- Mike Lee
- 1Department of Nutritional Science and Toxicology, University of California at Berkeley, Berkeley, California; and
| | - Sungwon Choi
- 1Department of Nutritional Science and Toxicology, University of California at Berkeley, Berkeley, California; and
| | - Gunnel Halldén
- 1Department of Nutritional Science and Toxicology, University of California at Berkeley, Berkeley, California; and
| | - Sek Jin Yo
- 1Department of Nutritional Science and Toxicology, University of California at Berkeley, Berkeley, California; and
| | - Denise Schichnes
- 2College of Natural Resources Biological Imaging Facility, University of California at Berkeley, Berkeley, California
| | - Gregory W. Aponte
- 1Department of Nutritional Science and Toxicology, University of California at Berkeley, Berkeley, California; and
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Huang C, Hydo LM, Liu S, Miller RT. Activation of choline kinase by extracellular Ca2+ is Ca(2+)-sensing receptor, Galpha12 and Rho-dependent in breast cancer cells. Cell Signal 2009; 21:1894-900. [PMID: 19716891 DOI: 10.1016/j.cellsig.2009.08.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 08/07/2009] [Accepted: 08/19/2009] [Indexed: 11/25/2022]
Abstract
Breast cancer cell metastases to bone result in osteolysis and release of large quantities of Ca2+ into the bone microenviroment. Extracellular Ca2+ (Ca(o)2+) acting through the Ca(2+)-sensing receptor (CaR), a member of G protein-coupled receptor superfamily, plays an important role in the regulation of multiple signaling pathways. Here, we find that expression of the CaR and Galpha(12) is significantly up-regulated in breast cancer cells (MDA-MB-231 and MCF-7) compared with nonmalignant breast cells (Hs 578Bst and MCF-10A). Ca(o)2+ induces a significant increase in extracellular [(3)H]phosphocholine (P-cho) production in breast cancer cells. Using an anti-CaR antibody to block Ca(o)2+ binding to the CaR and small interfering RNA (siRNA) to silence CaR gene expression, our data demonstrate that [(3)H]P-cho production in response to Ca(o)(2+)-stimulation is CaR-dependent. By analyzing cellular lipid profiles and using siRNA to silence choline kinase (ChoK) expression, we determine that the production of [3H]P-cho is primarily related to CaR-induced ChoK activation, and not degradation of choline phospholipids. Finally, by pretreatment of the cells with either pertussis toxin or C3 exoenzyme, co-immunoprecipiation of Galpha(i), Galpha(q) or Galpha12 with the CaR, and RhoA translocation, we found that the enhancement of ChoK activation and P-cho production in breast cancer cells occurs via a CaR-Galpha12-Rho signaling pathway.
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Affiliation(s)
- Chunfa Huang
- Louis Stokes Cleveland Veteran Affairs Medical Center, Cleveland, Ohio 44106, United States.
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Gamba G, Friedman PA. Thick ascending limb: the Na(+):K (+):2Cl (-) co-transporter, NKCC2, and the calcium-sensing receptor, CaSR. Pflugers Arch 2009; 458:61-76. [PMID: 18982348 PMCID: PMC3584568 DOI: 10.1007/s00424-008-0607-1] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 10/21/2008] [Indexed: 01/12/2023]
Abstract
The thick ascending limb of Henle's loop is a nephron segment that is vital to the formation of dilute and concentrated urine. This ability is accomplished by a consortium of functionally coupled proteins consisting of the apical Na(+):K(+):2Cl(-) co-transporter, the K(+) channel, and basolateral Cl(-) channel that mediate electroneutral salt absorption. In thick ascending limbs, salt absorption is importantly regulated by the calcium-sensing receptor. Genetic or pharmacological disruption impairing the function of any of these proteins results in Bartter syndrome. The thick ascending limb is also an important site of Ca(2+) and Mg(2+) absorption. Calcium-sensing receptor activation inhibits cellular Ca(2+) absorption induced by parathyroid hormone, as well as passive paracellular Ca(2+) transport. The present review discusses these functions and their genetic and molecular regulation.
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Affiliation(s)
- Gerardo Gamba
- Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, 14000 Mexico City, Mexico
| | - Peter A. Friedman
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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Ross-Inta CM, Zhang YF, Almendares A, Giulivi C. Threonine-deficient diets induced changes in hepatic bioenergetics. Am J Physiol Gastrointest Liver Physiol 2009; 296:G1130-9. [PMID: 19228885 PMCID: PMC2696218 DOI: 10.1152/ajpgi.90545.2008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Diets deficient in an indispensable amino acid are known to suppress food intake in rats. Few studies were focused at understanding how amino acid-deficient diets may elicit biochemical changes at the mitochondrial level. The goal of this study was to evaluate mitochondrial function in rats fed diets with 0.00, 0.18, 0.36, and 0.88% threonine (Thr) (set at 0, 30, 60, and 140% of Thr requirement for growth). Here, it is described for the first time that Thr-deficient diets induce a specific uncoupling of mitochondria in liver, especially with NADH-linked substrates, not observed in heart (except for Thr-devoid diet). The advantage of this situation would be to provide ATP to support growth and maintenance when high-quality protein food (or wealth of high-quality food in general) is available, whereas Thr-deficient diets (or deficient-quality protein food) promote the opposite, increasing mitochondrial uncoupling in liver. The uncoupling with NADH substrates would favor the use of nutrients as energy sources with higher FADH-to-NADH ratios, such as fat, minimizing the first irreversible NADH-dependent catabolism of many amino acids, including Thr, thus enhancing the use of the limiting amino acid for protein synthesis when a low quality protein source is available.
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Affiliation(s)
- Catherine M. Ross-Inta
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, California
| | - Yi-Fan Zhang
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, California
| | - Andrew Almendares
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, California
| | - Cecilia Giulivi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, California
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Abstract
The calcium-sensing receptor regulates various parathyroid gland functions, including hormone secretion, gene transcription, and chief cell hyperplasia through G alpha q- and G alpha i-dependent signaling pathways. To determine the specific function of G alpha q in these processes, we generated transgenic mice using the human parathyroid hormone promoter to drive overexpression of a dominant negative G alpha q loop minigene to selectively disrupt G alpha q function in the parathyroid gland. The G alpha q loop mRNA was highly expressed in the parathyroid gland but not in other tissues of these transgenic mice. Gross appearance, body weight, bone mineral density, and survival of the transgenic mice were indistinguishable from those of their wild-type littermates. Adult transgenic mice, however, exhibited an increase in parathyroid hormone mRNA and in its basal serum level as well as in gland size. The response of the parathyroid gland to hypocalcemia was found to be reduced in sensitivity in the transgenic mice when compared to their wild-type controls. Abnormalities of the parathyroid gland function in these transgenic mice were similar to those of heterozygous G alpha q(+/-) and calcium sensing receptor(+/-) mice. These studies demonstrate the feasibility of selectively targeting the parathyroid gland to investigate signaling mechanisms downstream of the calcium receptor.
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Kempson SA, Edwards JM, Osborn A, Sturek M. Acute inhibition of the betaine transporter by ATP and adenosine in renal MDCK cells. Am J Physiol Renal Physiol 2008; 295:F108-17. [PMID: 18448594 DOI: 10.1152/ajprenal.00108.2008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Extracellular ATP interacts with purinergic P2 receptors to regulate a range of physiological responses, including downregulation of transport activity in the nephron. ATP is released from cells by mechanical stimuli such as cell volume changes, and autocrine signaling by extracellular ATP could occur in renal medullary cells during diuresis. This was tested in Madin-Darby canine kidney (MDCK) cells, a model used frequently to study P1 and P2 receptor activity. ATP was released within 1 min after transfer from 500 to 300 mosmol/kgH2O medium. A 30-min incubation with ATP produced dose-dependent inhibition (0.01-0.10 mM) of the renal betaine/GABA transporter (BGT1) with little effect on other osmolyte transporters. Inhibition was reproduced by specific agonists for P2X (alpha,beta-methylene-ATP) and P2Y (UTP) receptors. Adenosine, the final product of ATP hydrolysis, also inhibited BGT1 but not taurine transport. Inhibition by ATP and adenosine was blocked by pertussis toxin and A73122, suggesting involvement of inhibitory G protein and PLC in postreceptor signaling. Both ATP and adenosine (0.1 mM) produced rapid increases in intracellular Ca2+, due to the mobilization of intracellular Ca2+ stores and Ca2+ influx. Blocking these Ca2+ increases with BAPTA-AM also blocked the action of ATP and adenosine on BGT1 transport. Finally, immunohistochemical studies indicated that inhibition of BGT1 transport may be due to endocytic accumulation of BGT1 proteins from the plasma membrane. We conclude that ATP and adenosine, through stimulation of PLC and intracellular Ca2+, may be rapidly acting regulators of BGT1 transport especially in response to a fall in extracellular osmolarity.
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Affiliation(s)
- Stephen A Kempson
- Department of Cellular and Intergrative Physiology, Indiana University School of Medicine, Indianapolis, IN, USA.
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Extracellular calcium-sensing receptors in fishes. Comp Biochem Physiol A Mol Integr Physiol 2008; 149:225-45. [DOI: 10.1016/j.cbpa.2008.01.037] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Revised: 01/23/2008] [Accepted: 01/23/2008] [Indexed: 11/19/2022]
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Sabath E, Negoro H, Beaudry S, Paniagua M, Angelow S, Shah J, Grammatikakis N, Yu ASL, Denker BM. Galpha12 regulates protein interactions within the MDCK cell tight junction and inhibits tight-junction assembly. J Cell Sci 2008; 121:814-24. [PMID: 18285450 DOI: 10.1242/jcs.014878] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The polarized functions of epithelia require an intact tight junction (TJ) to restrict paracellular movement and to separate membrane proteins into specific domains. TJs contain scaffolding, integral membrane and signaling proteins, but the mechanisms that regulate TJs and their assembly are not well defined. Galpha12 (GNA12) binds the TJ protein ZO-1 (TJP1), and Galpha12 activates Src to increase paracellular permeability via unknown mechanisms. Herein, we identify Src as a component of the TJ and find that recruitment of Hsp90 to activated Galpha12 is necessary for signaling. TJ integrity is disrupted by Galpha12-stimulated Src phosphorylation of ZO-1 and ZO-2 (TJP2); this phosphorylation leads to dissociation of occludin and claudin 1 from the ZO-1 protein complex. Inhibiting Hsp90 with geldanamycin blocks Galpha12-stimulated Src activation and phosphorylation, but does not affect protein levels or the Galpha12-ZO-1 interaction. Using the calcium-switch model of TJ assembly and GST-TPR (GST-fused TPR domain of PP5) pull-downs of activated Galpha12, we demonstrate that switching to normal calcium medium activates endogenous Galpha12 during TJ assembly. Thrombin increases permeability and delays TJ assembly by activating Galpha12, but not Galpha13, signaling pathways. These findings reveal an important role for Galpha12, Src and Hsp90 in regulating the TJ in established epithelia and during TJ assembly.
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Affiliation(s)
- Ernesto Sabath
- Renal Division, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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