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Vilardaga JP, Clark LJ, White AD, Sutkeviciute I, Lee JY, Bahar I. Molecular Mechanisms of PTH/PTHrP Class B GPCR Signaling and Pharmacological Implications. Endocr Rev 2023; 44:474-491. [PMID: 36503956 PMCID: PMC10461325 DOI: 10.1210/endrev/bnac032] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 11/14/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022]
Abstract
The classical paradigm of G protein-coupled receptor (GPCR) signaling via G proteins is grounded in a view that downstream responses are relatively transient and confined to the cell surface, but this notion has been revised in recent years following the identification of several receptors that engage in sustained signaling responses from subcellular compartments following internalization of the ligand-receptor complex. This phenomenon was initially discovered for the parathyroid hormone (PTH) type 1 receptor (PTH1R), a vital GPCR for maintaining normal calcium and phosphate levels in the body with the paradoxical ability to build or break down bone in response to PTH binding. The diverse biological processes regulated by this receptor are thought to depend on its capacity to mediate diverse modes of cyclic adenosine monophosphate (cAMP) signaling. These include transient signaling at the plasma membrane and sustained signaling from internalized PTH1R within early endosomes mediated by PTH. Here we discuss recent structural, cell signaling, and in vivo studies that unveil potential pharmacological outputs of the spatial versus temporal dimension of PTH1R signaling via cAMP. Notably, the combination of molecular dynamics simulations and elastic network model-based methods revealed how precise modulation of PTH signaling responses is achieved through structure-encoded allosteric coupling within the receptor and between the peptide hormone binding site and the G protein coupling interface. The implications of recent findings are now being explored for addressing key questions on how location bias in receptor signaling contributes to pharmacological functions, and how to drug a difficult target such as the PTH1R toward discovering nonpeptidic small molecule candidates for the treatment of metabolic bone and mineral diseases.
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Affiliation(s)
- Jean-Pierre Vilardaga
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Lisa J Clark
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Alex D White
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Ieva Sutkeviciute
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Ji Young Lee
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Ivet Bahar
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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Altered signaling at the PTH receptor via modified agonist contacts with the extracellular domain provides a path to prolonged agonism in vivo. Proc Natl Acad Sci U S A 2022; 119:e2212736119. [PMID: 36409914 PMCID: PMC9860328 DOI: 10.1073/pnas.2212736119] [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: 11/22/2022] Open
Abstract
The parathyroid hormone type 1 receptor (PTHR1), a Class B GPCR, is activated by long polypeptides, including drugs for osteoporosis and hypoparathyroidism. The PTHR1 engages peptide agonists via a two-step mechanism. Initial contact involves the extracellular domain (ECD), which has been thought to contribute primarily to receptor-peptide binding, and then the N terminus of the peptide engages the receptor transmembrane domain (TMD), which is thought to control the message conveyed to intracellular partners. This mechanism has been suggested to apply to other Class B GPCRs as well. Here, we show that modification of a PTHR1 agonist at ECD-contact sites can alter the signaling profile, an outcome that is not accommodated by the current two-step binding model. Our data support a modified two-step binding model in which agonist orientation on the ECD surface can influence the geometry of agonist-TMD engagement. This expanded binding model offers a mechanism by which altering ECD-contact residues can affect signaling profile. Our discoveries provide a rationale for exploring agonist modifications distal from the TMD-contact region in future efforts to optimize therapeutic performance of peptide hormone analogs.
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Smylla TK, Wagner K, Huber A. The Role of Reversible Phosphorylation of Drosophila Rhodopsin. Int J Mol Sci 2022; 23:ijms232314674. [PMID: 36499010 PMCID: PMC9740569 DOI: 10.3390/ijms232314674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 11/27/2022] Open
Abstract
Vertebrate and fly rhodopsins are prototypical GPCRs that have served for a long time as model systems for understanding GPCR signaling. Although all rhodopsins seem to become phosphorylated at their C-terminal region following activation by light, the role of this phosphorylation is not uniform. Two major functions of rhodopsin phosphorylation have been described: (1) inactivation of the activated rhodopsin either directly or by facilitating binding of arrestins in order to shut down the visual signaling cascade and thus eventually enabling a high-temporal resolution of the visual system. (2) Facilitating endocytosis of activated receptors via arrestin binding that in turn recruits clathrin to the membrane for clathrin-mediated endocytosis. In vertebrate rhodopsins the shutdown of the signaling cascade may be the main function of rhodopsin phosphorylation, as phosphorylation alone already quenches transducin activation and, in addition, strongly enhances arrestin binding. In the Drosophila visual system rhodopsin phosphorylation is not needed for receptor inactivation. Its role here may rather lie in the recruitment of arrestin 1 and subsequent endocytosis of the activated receptor. In this review, we summarize investigations of fly rhodopsin phosphorylation spanning four decades and contextualize them with regard to the most recent insights from vertebrate phosphorylation barcode theory.
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Carrasco-Ruiz MF, Ruiz-Rivera A, Soriano-Ursúa MA, Martinez-Hernandez C, Manuel-Apolinar L, Castillo-Hernandez C, Guevara-Balcazar G, Farfán-García ED, Mejia-Ruiz A, Rubio-Gayosso I, Perez-Capistran T. Global longitudinal strain is superior to ejection fraction for detecting myocardial dysfunction in end-stage renal disease with hyperparathyroidism. World J Cardiol 2022; 14:239-249. [PMID: 35582470 PMCID: PMC9048274 DOI: 10.4330/wjc.v14.i4.239] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/07/2022] [Accepted: 04/04/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The estimation of left ventricular ejection fraction (LVEF) by 2D echocardiography (2D-ECHO) is the most used tool to assess LV systolic function (LVSF). Global longitudinal strain (GLS) has recently been suggested as a superior method for several evaluations. This study explored the association and prevalence of LV systolic dysfunction (LVSD) by using these methods in patients with end-stage renal disease (ESRD) and severe hyperparathyroidism (SHPTH); both associated with cardiovascular events (CEs).
AIM To evaluate the myocardial function in patients with ESRD and SHPTH by using the GLS and LVEF measured through conventional 2D-ECHO.
METHODS In 62 patients with ESRD and SHPTH, asymptomatic, and without a history of CEs, LVSF was evaluated by 2D-ECHO, obtaining the EF, by the Simpson biplane method, and GLS by speckle tracking.
RESULTS The total patients with ESRD had a preserved LVEF (> 50%) but abnormal GLS (< 13.55%). Additionally, multivariate analysis showed an independent association of GLS and serum parathyroid hormone (PTH), LV mass index, and hemoglobin. Also, PTH was independently associated with lateral e' wave and tricuspid regurgitation velocity.
CONCLUSION In patients with SHPTH linked to ESRD, the use of GLS by 2D-ECHO is a more sensitive tool than LVEF for detecting LVSD.
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Affiliation(s)
- Maria Fernanda Carrasco-Ruiz
- Department of Physiology, Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico
| | - Antonio Ruiz-Rivera
- Department of Cardiology, Instituto Mexicano del Seguro Social, Ciudad de México 06720, Mexico
| | - Marvin A Soriano-Ursúa
- Department of Physiology, Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico
| | | | - Leticia Manuel-Apolinar
- Endocrine Research Unit, Instituto Mexicano del Seguro Social, Ciudad de México 06720, Mexico
| | - Carmen Castillo-Hernandez
- Department of Cardiovascular Pharmacology, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico
| | - Gustavo Guevara-Balcazar
- Department of Cardiovascular Pharmacology, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico
| | - Eunice D Farfán-García
- Department of Biochemistry, Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico
| | - Ana Mejia-Ruiz
- Education Research, Comisión Nacional Para la Mejora Continua de la Educación, Ciudad de México 03900, Mexico
| | - Ivan Rubio-Gayosso
- Postgraduate Studies and Research Section,Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico
| | - Teresa Perez-Capistran
- Department of Physiology, Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico
- Department of Physiology, Instituto Politécnico Nacional, Mexico City 11340, Ciudad de México, Mexico
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Activity-based, bioorthogonal imaging of phospholipase D reveals spatiotemporal dynamics of GPCR-Gq signaling. Cell Chem Biol 2022; 29:67-73.e3. [PMID: 34161786 PMCID: PMC8655016 DOI: 10.1016/j.chembiol.2021.05.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/29/2021] [Accepted: 05/27/2021] [Indexed: 01/22/2023]
Abstract
Canonically, G-protein-coupled receptor (GPCR) signaling is transient and confined to the plasma membrane (PM). Deviating from this paradigm, the parathyroid hormone receptor (PTHR1) stimulates sustained Gs signaling at endosomes. In addition to Gs, PTHR1 activates Gq signaling; yet, in contrast to the PTHR1-Gs pathway, the spatiotemporal dynamics of the Gq branch of PTHR1 signaling and its relationship to Gs signaling remain largely ill defined. Recognizing that a downstream consequence of Gq signaling is the activation of phospholipase D (PLD) enzymes, we leverage activity-based, bioorthogonal imaging tools for PLD signaling to visualize and quantify the Gq branch of PTHR1 signaling. We establish that PTHR1-Gq signaling is short lived, exclusively at the PM, and antagonized by PTHR1 endocytosis. Our data support a model wherein Gq and Gs compete for ligand-bound receptors at the PM and more broadly highlight the utility of bioorthogonal tools for imaging PLDs as probes to visualize GPCR-Gq signaling.
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White AD, Peña KA, Clark LJ, Maria CS, Liu S, Jean-Alphonse FG, Lee JY, Lei S, Cheng Z, Tu CL, Fang F, Szeto N, Gardella TJ, Xiao K, Gellman SH, Bahar I, Sutkeviciute I, Chang W, Vilardaga JP. Spatial bias in cAMP generation determines biological responses to PTH type 1 receptor activation. Sci Signal 2021; 14:eabc5944. [PMID: 34609896 PMCID: PMC8682804 DOI: 10.1126/scisignal.abc5944] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
[Figure: see text].
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Affiliation(s)
- Alex D White
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA.,Graduate Program in Molecular Pharmacology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Karina A Peña
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Lisa J Clark
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA.,Graduate Program in Molecular Biology and Structural Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Christian Santa Maria
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, and University of California, San Francisco, CA 94158, USA
| | - Shi Liu
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Frédéric G Jean-Alphonse
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Ji Young Lee
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Saifei Lei
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Zhiqiang Cheng
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, and University of California, San Francisco, CA 94158, USA
| | - Chia-Ling Tu
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, and University of California, San Francisco, CA 94158, USA
| | - Fei Fang
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Nicholas Szeto
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, and University of California, San Francisco, CA 94158, USA
| | - Thomas J Gardella
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Kunhong Xiao
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Samuel H Gellman
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Ivet Bahar
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Ieva Sutkeviciute
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Wenhan Chang
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, and University of California, San Francisco, CA 94158, USA
| | - Jean-Pierre Vilardaga
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
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Kalinkovich A, Livshits G. Biased and allosteric modulation of bone cell-expressing G protein-coupled receptors as a novel approach to osteoporosis therapy. Pharmacol Res 2021; 171:105794. [PMID: 34329703 DOI: 10.1016/j.phrs.2021.105794] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/20/2021] [Accepted: 07/25/2021] [Indexed: 12/16/2022]
Abstract
On the cellular level, osteoporosis (OP) is a result of imbalanced bone remodeling, in which osteoclastic bone resorption outcompetes osteoblastic bone formation. Currently available OP medications include both antiresorptive and bone-forming drugs. However, their long-term use in OP patients, mainly in postmenopausal women, is accompanied by severe side effects. Notably, the fundamental coupling between bone resorption and formation processes underlies the existence of an undesirable secondary outcome that bone anabolic or anti-resorptive drugs also reduce bone formation. This drawback requires the development of anti-OP drugs capable of selectively stimulating osteoblastogenesis and concomitantly reducing osteoclastogenesis. We propose that the application of small synthetic biased and allosteric modulators of bone cell receptors, which belong to the G-protein coupled receptors (GPCR) family, could be the key to resolving the undesired anti-OP drug selectivity. This approach is based on the capacity of these GPCR modulators, unlike the natural ligands, to trigger signaling pathways that promote beneficial effects on bone remodeling while blocking potentially deleterious effects. Under the settings of OP, an optimal anti-OP drug should provide fine-tuned regulation of downstream effects, for example, intermittent cyclic AMP (cAMP) elevation, preservation of Ca2+ balance, stimulation of osteoprotegerin (OPG) and estrogen production, suppression of sclerostin secretion, and/or preserved/enhanced canonical β-catenin/Wnt signaling pathway. As such, selective modulation of GPCRs involved in bone remodeling presents a promising approach in OP treatment. This review focuses on the evidence for the validity of our hypothesis.
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Affiliation(s)
- Alexander Kalinkovich
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 6905126, Israel
| | - Gregory Livshits
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 6905126, Israel; Adelson School of Medicine, Ariel University, Ariel 4077625, Israel.
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Poll BG, Chen L, Chou CL, Raghuram V, Knepper MA. Landscape of GPCR expression along the mouse nephron. Am J Physiol Renal Physiol 2021; 321:F50-F68. [PMID: 34029142 PMCID: PMC8321805 DOI: 10.1152/ajprenal.00077.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 05/20/2021] [Accepted: 05/20/2021] [Indexed: 12/11/2022] Open
Abstract
Kidney transport and other renal functions are regulated by multiple G protein-coupled receptors (GPCRs) expressed along the renal tubule. The rapid, recent appearance of comprehensive unbiased gene expression data in the various renal tubule segments, chiefly RNA sequencing and protein mass spectrometry data, has provided a means of identifying patterns of GPCR expression along the renal tubule. To allow for comprehensive mapping, we first curated a comprehensive list of GPCRs in the genomes of mice, rats, and humans (https://hpcwebapps.cit.nih.gov/ESBL/Database/GPCRs/) using multiple online data sources. We used this list to mine segment-specific and cell type-specific expression data from RNA-sequencing studies in microdissected mouse tubule segments to identify GPCRs that are selectively expressed in discrete tubule segments. Comparisons of these mapped mouse GPCRs with other omics datasets as well as functional data from isolated perfused tubule and micropuncture studies confirmed patterns of expression for well-known receptors and identified poorly studied GPCRs that are likely to play roles in the regulation of renal tubule function. Thus, we provide data resources for GPCR expression across the renal tubule, highlighting both well-known GPCRs and understudied receptors to provide guidance for future studies.
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Affiliation(s)
- Brian G Poll
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Lihe Chen
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Chung-Lin Chou
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Viswanathan Raghuram
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Mark A Knepper
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
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Jullié D, Gondin AB, von Zastrow M, Canals M. Opioid Pharmacology under the Microscope. Mol Pharmacol 2020; 98:425-432. [PMID: 32198210 DOI: 10.1124/mol.119.119321] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 03/10/2020] [Indexed: 12/18/2022] Open
Abstract
The powerful analgesic effects of opioid drugs have captivated the interest of physicians and scientists for millennia, and the ability of opioid drugs to produce serious undesired effects has been recognized for a similar period of time (Kieffer and Evans, 2009). Many of these develop progressively with prolonged or repeated drug use and then persist, motivating particular interest in understanding how opioid drugs initiate adaptive or maladaptive modifications in neural function or regulation. Exciting advances have been made over the past several years in elucidating drug-induced changes at molecular, cellular, and physiologic scales of analysis. The present review will highlight some recent cellular studies that we believe bridge across scales and will focus on optical imaging approaches that put opioid drug action "under the microscope." SIGNIFICANCE STATEMENT: Opioid receptors are major pharmacological targets, but their signaling at the cellular level results from a complex interplay between pharmacology, regulation, subcellular localization, and membrane trafficking. This minireview discusses recent advances in understanding the cellular biology of opioid receptors, emphasizing particular topics discussed at the 50th anniversary of the International Narcotics Research Conference. Our goal is to highlight distinct signaling and regulatory properties emerging from the cellular biology of opioid receptors and discuss potential relevance to therapeutics.
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Affiliation(s)
- Damien Jullié
- Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco School of Medicine, San Francisco, California (D.J., M.v.Z.); Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia (A.B.G.); Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom (M.C.); and Centre of Membrane Protein and Receptors, Universities of Birmingham and Nottingham, The Midlands, United Kingdom (M.C.)
| | - Arisbel B Gondin
- Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco School of Medicine, San Francisco, California (D.J., M.v.Z.); Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia (A.B.G.); Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom (M.C.); and Centre of Membrane Protein and Receptors, Universities of Birmingham and Nottingham, The Midlands, United Kingdom (M.C.)
| | - Mark von Zastrow
- Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco School of Medicine, San Francisco, California (D.J., M.v.Z.); Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia (A.B.G.); Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom (M.C.); and Centre of Membrane Protein and Receptors, Universities of Birmingham and Nottingham, The Midlands, United Kingdom (M.C.)
| | - Meritxell Canals
- Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco School of Medicine, San Francisco, California (D.J., M.v.Z.); Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia (A.B.G.); Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom (M.C.); and Centre of Membrane Protein and Receptors, Universities of Birmingham and Nottingham, The Midlands, United Kingdom (M.C.)
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10
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He Y, Liu RX, Zhu MT, Shen WB, Xie J, Zhang ZY, Chen N, Shan C, Guo XZ, Lu YD, Tao B, Sun LH, Zhao HY, Guo R, Li B, Liu SM, Ning G, Wang JQ, Liu JM. The browning of white adipose tissue and body weight loss in primary hyperparathyroidism. EBioMedicine 2018; 40:56-66. [PMID: 30528454 PMCID: PMC6412009 DOI: 10.1016/j.ebiom.2018.11.057] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 11/27/2018] [Accepted: 11/27/2018] [Indexed: 12/24/2022] Open
Abstract
Background Parathyroid hormone related protein (PTHrP) triggers white adipose tissue (WAT) browning and cachexia in lung cancer mouse models. It remains unknown whether excessive PTH secretion affects WAT browning and to what extent it contributes to body weight change in primary hyperparathyroidism (PHPT). Methods Using the adeno-associated virus injection, Pth gene over-expressed mice mimicking PHPT were firstly established to observe their WAT browning and body weight alteration. The association between PTH and body weight was investigated in 496 PHPT patients. The adipose browning activities of 20 PHPT and 60 control subjects were measured with PET/CT scanning. Findings Elevated plasma PTH triggered adipose tissue browning, leading to increased energy expenditure, reduced fat content, and finally decreased body weight in PHPT mice. Higher circulating PTH levels were associated with lower body weight (β = −0.048, P = .0003) independent of renal function, serum calcium, phosphorus,and albumin levels in PHPT patients. PHPT patients exhibited both higher prevalence of detectable brown/beige adipose tissue (20% vs 3.3%, P = .03) and increased browning activities (SUV in cervical adipose was 0.77 vs 0.49,P = .02) compared with control subjects. Interpretation Elevated serum PTH drove WAT browning program, which contributed in part to body weight loss in both PHPT mice and patients. These results give insights into the novel pathological effect of PTH and are of importance in understanding the metabolic changes of PHPT. Fund This research is supported by the National Key Research and Development Program of China and National Natural Science Foundation of China.
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Affiliation(s)
- Yang He
- Department of Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai 200025, China
| | - Rui-Xin Liu
- Department of Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai 200025, China
| | - Min-Ting Zhu
- Department of Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai 200025, China
| | - Wen-Bin Shen
- Department of Nuclear Medicine, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai 200025, China
| | - Jing Xie
- Department of Pathology, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai 200025, China
| | - Zhi-Yin Zhang
- Department of Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai 200025, China
| | - Na Chen
- Department of Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai 200025, China
| | - Chang Shan
- Department of Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai 200025, China
| | - Xing-Zhi Guo
- Department of Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai 200025, China
| | - Yi-de Lu
- Clinical Laboratory, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai 200025, China
| | - Bei Tao
- Department of Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai 200025, China
| | - Li-Hao Sun
- Department of Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai 200025, China
| | - Hong-Yan Zhao
- Department of Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai 200025, China
| | - Rui Guo
- Department of Nuclear Medicine, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai 200025, China
| | - Biao Li
- Department of Nuclear Medicine, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai 200025, China
| | - Si-Min Liu
- Department of Epidemiology and Center for Global Cardiometabolic Health, School of Public Health, Department of Medicine (Endocrinology), The Warren Alpert Medical School, Brown University, Providence, RI, USA
| | - Guang Ning
- Department of Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai 200025, China.
| | - Ji-Qiu Wang
- Department of Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai 200025, China.
| | - Jian-Min Liu
- Department of Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai 200025, China.
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11
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Abstract
β-arrestin1 (or arrestin2) and β-arrestin2 (or arrestin3) are ubiquitously expressed cytosolic adaptor proteins that were originally discovered for their inhibitory role in G protein-coupled receptor (GPCR) signaling through heterotrimeric G proteins. However, further biochemical characterization revealed that β-arrestins do not just "block" the activated GPCRs, but trigger endocytosis and kinase activation leading to specific signaling pathways that can be localized on endosomes. The signaling pathways initiated by β-arrestins were also found to be independent of G protein activation by GPCRs. The discovery of ligands that blocked G protein activation but promoted β-arrestin binding, or vice-versa, suggested the exciting possibility of selectively activating intracellular signaling pathways. In addition, it is becoming increasingly evident that β-arrestin-dependent signaling is extremely diverse and provokes distinct cellular responses through different GPCRs even when the same effector kinase is involved. In this review, we summarize various signaling pathways mediated by β-arrestins and highlight the physiologic effects of β-arrestin-dependent signaling.
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12
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Bhosle VK, Rivera JC, Chemtob S. New insights into mechanisms of nuclear translocation of G-protein coupled receptors. Small GTPases 2017; 10:254-263. [PMID: 28125336 DOI: 10.1080/21541248.2017.1282402] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The G-protein coupled receptor (GPCR) signaling was long believed to involve activation of receptor exclusively at the cell surface, followed by its binding to heterotrimeric G-proteins and arrestins to trigger various intracellular signaling cascades, and termination of signaling by internalization of the receptor. It is now accepted that many GPCRs continue to signal after internalization in the endosomes. Since the breakthrough discoveries of nuclear binding sites for their ligands in 1980s, several GPCRs have been detected at cell nuclei. But mechanisms of nuclear localization of GPCRs, many of whom contain putative nuclear localization signals, remain poorly understood to date. Nevertheless, it is known that subcellular trafficking of GPCRs is regulated by members of Ras superfamily of small GTPases, most notably by Rab and Arf GTPases. In this commentary, we highlight several recent studies which suggest novel roles of small GTPases, importins and sorting nexin proteins in the nuclear translocation of GPCRs via vesicular transport pathways. Taken together with increasing evidence for in vivo functionality of the nuclear GPCRs, better understanding of their trafficking will provide valuable clues in cell biology.
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Affiliation(s)
- Vikrant K Bhosle
- a Department of Pharmacology and Therapeutics , McGill University , Montréal , Québec , Canada.,b CHU Sainte-Justine Hospital Research Centre , University of Montréal , Montréal , Québec , Canada.,c Maisonneuve-Rosemont Hospital Research Centre , University of Montréal , Montréal , Québec , Canada.,e Cell Biology Program , Peter Gilgan Centre for Research and Learning , Toronto , Ontario , Canada
| | - José Carlos Rivera
- b CHU Sainte-Justine Hospital Research Centre , University of Montréal , Montréal , Québec , Canada.,c Maisonneuve-Rosemont Hospital Research Centre , University of Montréal , Montréal , Québec , Canada
| | - Sylvain Chemtob
- a Department of Pharmacology and Therapeutics , McGill University , Montréal , Québec , Canada.,b CHU Sainte-Justine Hospital Research Centre , University of Montréal , Montréal , Québec , Canada.,c Maisonneuve-Rosemont Hospital Research Centre , University of Montréal , Montréal , Québec , Canada.,d Departments of Pediatrics, Ophthalmology and Pharmacology , University of Montréal , Montréal , Québec , Canada
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13
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Abstract
G protein-coupled receptors (GPCRs) are often pleiotropically linked to numerous cellular signaling mechanisms in cells, and it is now known that many agonists differentially activate some signaling pathways at the expense of others. The mechanism for this effect is the stabilization of different active receptor states by different agonists, and it leads to varying qualities of efficacy for different agonists. Agonist bias is a powerful mechanism to amplify beneficial signals and diminish harmful signals, and thus improve the overall profile of agonist ligands. This unit describes a method to quantify agonist bias with a scale that enables medicinal chemists to amplify or reduce these effects in new molecules. The method is based on the Black/Leff operational model and yields a statistical estimate of the confidence for bias measurements. © 2016 by John Wiley & Sons, Inc.
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Affiliation(s)
- Terry Kenakin
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
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14
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Costa-Neto CM, Parreiras-E-Silva LT, Bouvier M. A Pluridimensional View of Biased Agonism. Mol Pharmacol 2016; 90:587-595. [PMID: 27638872 DOI: 10.1124/mol.116.105940] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 09/14/2016] [Indexed: 12/17/2022] Open
Abstract
When studying G protein-coupled receptor (GPCR) signaling and ligand-biased agonism, at least three dimensional spaces must be considered, as follows: 1) the distinct conformations that can be stabilized by different ligands promoting the engagement of different signaling effectors and accessory regulators; 2) the distinct subcellular trafficking that can be conferred by different ligands, which results in spatially distinct signals; and 3) the differential binding kinetics that maintain the receptor in specific conformation and/or subcellular localization for different periods of time, allowing for the engagement of distinct signaling effector subsets. These three pluridimensional aspects of signaling contribute to different faces of functional selectivity and provide a complex, interconnected way to define the signaling profile of each individual ligand acting at GPCRs. In this review, we discuss how each of these aspects may contribute to the diversity of signaling, but also how they shed light on the complexity of data analyses and interpretation. The impact of phenotype variability as a source of signaling diversity, and the influence of novel and more sensitive assays in the detection and analysis of signaling pluridimensionality, is also discussed. Finally, we discuss perspectives for the use of the concept of pluridimensional signaling in drug discovery, in which we highlight future predictive tools that may facilitate the identification of compounds with optimal therapeutic and safety properties based on the signaling signatures of drug candidates.
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Affiliation(s)
- Claudio M Costa-Neto
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of São Paulo, Ribeirao Preto, Brazil (C.M.C.-N., L.T.P.-S.); and Department of Biochemistry and Molecular Medicine and Institute for Research in Immunology and Cancer, University of Montréal, Montréal, Canada (L.T.P.-S., M.B.)
| | - Lucas T Parreiras-E-Silva
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of São Paulo, Ribeirao Preto, Brazil (C.M.C.-N., L.T.P.-S.); and Department of Biochemistry and Molecular Medicine and Institute for Research in Immunology and Cancer, University of Montréal, Montréal, Canada (L.T.P.-S., M.B.)
| | - Michel Bouvier
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of São Paulo, Ribeirao Preto, Brazil (C.M.C.-N., L.T.P.-S.); and Department of Biochemistry and Molecular Medicine and Institute for Research in Immunology and Cancer, University of Montréal, Montréal, Canada (L.T.P.-S., M.B.)
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15
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BRET-based β-arrestin2 recruitment to the histamine H1 receptor for investigating antihistamine binding kinetics. Pharmacol Res 2016; 111:679-687. [PMID: 27468652 DOI: 10.1016/j.phrs.2016.07.034] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/14/2016] [Accepted: 07/24/2016] [Indexed: 01/23/2023]
Abstract
Ligand residence time is thought to be a critical parameter for optimizing the in vivo efficacy of drug candidates. For the histamine H1 receptor (H1R) and other G protein-coupled receptors, the kinetics of ligand binding are typically measured by low throughput radioligand binding experiments using homogenized cell membranes expressing the target receptor. In this study, a real-time proximity assay between H1R and β-arrestin2 in living cells was established to investigate the dynamics of antihistamine binding to the H1R. No receptor reserve was found for the histamine-induced recruitment of β-arrestin2 to the H1R and the transiently recruited β-arrestin2 therefore reflected occupancy of the receptor by histamine. Antihistamines displayed similar kinetic signatures on antagonizing histamine-induced β-arrestin2 recruitment as compared to displacing radioligand binding from the H1R. This homogeneous functional method unambiguously determined the fifty-fold difference in the dissociation rate constant between mepyramine and the long residence time antihistamines levocetirizine and desloratadine.
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16
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Martin TJ. Parathyroid Hormone-Related Protein, Its Regulation of Cartilage and Bone Development, and Role in Treating Bone Diseases. Physiol Rev 2016; 96:831-71. [DOI: 10.1152/physrev.00031.2015] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Although parathyroid hormone-related protein (PTHrP) was discovered as a cancer-derived hormone, it has been revealed as an important paracrine/autocrine regulator in many tissues, where its effects are context dependent. Thus its location and action in the vasculature explained decades-long observations that injection of PTH into animals rapidly lowered blood pressure by producing vasodilatation. Its roles have been specified in development and maturity in cartilage and bone as a crucial regulator of endochondral bone formation and bone remodeling, respectively. Although it shares actions with parathyroid hormone (PTH) through the use of their common receptor, PTHR1, PTHrP has other actions mediated by regions within the molecule beyond the amino-terminal sequence that resembles PTH, including the ability to promote placental transfer of calcium from mother to fetus. A striking feature of the physiology of PTHrP is that it possesses structural features that equip it to be transported in and out of the nucleus, and makes use of a specific nuclear import mechanism to do so. Evidence from mouse genetic experiments shows that PTHrP generated locally in bone is essential for normal bone remodeling. Whereas the main physiological function of PTH is the hormonal regulation of calcium metabolism, locally generated PTHrP is the important physiological mediator of bone remodeling postnatally. Thus the use of intermittent injection of PTH as an anabolic therapy for bone appears to be a pharmacological application of the physiological function of PTHrP. There is much current interest in the possibility of developing PTHrP analogs that might enhance the therapeutic anabolic effects.
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Affiliation(s)
- T. John Martin
- St Vincent's Institute of Medical Research, Department of Medicine, University of Melbourne, St Vincent's Hospital, Melbourne, Australia
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17
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Xiong L, Xia WF, Tang FL, Pan JX, Mei L, Xiong WC. Retromer in Osteoblasts Interacts With Protein Phosphatase 1 Regulator Subunit 14C, Terminates Parathyroid Hormone's Signaling, and Promotes Its Catabolic Response. EBioMedicine 2016; 9:45-60. [PMID: 27333042 PMCID: PMC4972523 DOI: 10.1016/j.ebiom.2016.05.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 05/11/2016] [Accepted: 05/24/2016] [Indexed: 12/02/2022] Open
Abstract
Parathyroid hormone (PTH) plays critical, but distinct, roles in bone remodeling, including bone formation (anabolic response) and resorption (catabolic response). Although its signaling and function have been extensively investigated, it just began to be understood how distinct functions are induced by PTH activating a common receptor, the PTH type 1 receptor (PTH1R), and how PTH1R signaling is terminated. Here, we provide evidence for vacuolar protein sorting 35 (VPS35), a major component of retromer, in regulating PTH1R trafficking, turning off PTH signaling, and promoting its catabolic function. VPS35 is expressed in osteoblast (OB)-lineage cells. VPS35-deficiency in OBs impaired PTH(1–34)-promoted PTH1R translocation to the trans-Golgi network, enhanced PTH(1–34)-driven signaling, and reduced PTH(1–34)'s catabolic response in culture and in mice. Further mechanical studies revealed that VPS35 interacts with not only PTH1R, but also protein phosphatase 1 regulatory subunit 14C (PPP1R14C), an inhibitory subunit of PP1 phosphatase. PPP1R14C also interacts with PTH1R, which is necessary for the increased endosomal PTH1R signaling and decreased PTH(1–34)'s catabolic response in VPS35-deficient OB-lineage cells. Taken together, these results suggest that VPS35 deregulates PTH1R-signaling likely by its interaction with PTH1R and PPP1R14C. This event is critical for the control of PTH(1–34)-signaling dynamics, which may underlie PTH-induced catabolic response and adequate bone remodeling. VPS35 terminates PTH(1-34)-induced cell surface and endosomal signalings Osteoblastic VPS35 promotes PTH(1-34)-driven catabolic response VPS35 interacts with PPP1R14C PPP1R14C also interacts with PTH1R and promotes PTH(1-34)-induced endosomal signaling PPP1R14C is necessary for the increased endosomal PTH1R signaling and decreased PTH(1-34)’s catabolic response in VPS35-deficient OB-lineage cells
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Affiliation(s)
- Lei Xiong
- Department of Neuroscience & Regenerative Medicine, Department of Neurology, Medical College of Georgia, Augusta, GA 30912, United States; Charlie Norwood VA Medical Center, Augusta, GA 30912, United States
| | - Wen-Fang Xia
- Department of Neuroscience & Regenerative Medicine, Department of Neurology, Medical College of Georgia, Augusta, GA 30912, United States; Charlie Norwood VA Medical Center, Augusta, GA 30912, United States; Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Fu-Lei Tang
- Department of Neuroscience & Regenerative Medicine, Department of Neurology, Medical College of Georgia, Augusta, GA 30912, United States; Charlie Norwood VA Medical Center, Augusta, GA 30912, United States
| | - Jin-Xiu Pan
- Department of Neuroscience & Regenerative Medicine, Department of Neurology, Medical College of Georgia, Augusta, GA 30912, United States; Charlie Norwood VA Medical Center, Augusta, GA 30912, United States
| | - Lin Mei
- Department of Neuroscience & Regenerative Medicine, Department of Neurology, Medical College of Georgia, Augusta, GA 30912, United States; Charlie Norwood VA Medical Center, Augusta, GA 30912, United States
| | - Wen-Cheng Xiong
- Department of Neuroscience & Regenerative Medicine, Department of Neurology, Medical College of Georgia, Augusta, GA 30912, United States; Charlie Norwood VA Medical Center, Augusta, GA 30912, United States.
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18
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Abstract
PTH and Vitamin D are two major regulators of mineral metabolism. They play critical roles in the maintenance of calcium and phosphate homeostasis as well as the development and maintenance of bone health. PTH and Vitamin D form a tightly controlled feedback cycle, PTH being a major stimulator of vitamin D synthesis in the kidney while vitamin D exerts negative feedback on PTH secretion. The major function of PTH and major physiologic regulator is circulating ionized calcium. The effects of PTH on gut, kidney, and bone serve to maintain serum calcium within a tight range. PTH has a reciprocal effect on phosphate metabolism. In contrast, vitamin D has a stimulatory effect on both calcium and phosphate homeostasis, playing a key role in providing adequate mineral for normal bone formation. Both hormones act in concert with the more recently discovered FGF23 and klotho, hormones involved predominantly in phosphate metabolism, which also participate in this closely knit feedback circuit. Of great interest are recent studies demonstrating effects of both PTH and vitamin D on the cardiovascular system. Hyperparathyroidism and vitamin D deficiency have been implicated in a variety of cardiovascular disorders including hypertension, atherosclerosis, vascular calcification, and kidney failure. Both hormones have direct effects on the endothelium, heart, and other vascular structures. How these effects of PTH and vitamin D interface with the regulation of bone formation are the subject of intense investigation.
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Affiliation(s)
- Syed Jalal Khundmiri
- Department of Medicine, University of Louisville, Louisville, Kentucky, USA
- Department of Physiology and Biophysics, University of Louisville, Louisville, Kentucky, USA
| | - Rebecca D. Murray
- Department of Medicine, University of Louisville, Louisville, Kentucky, USA
- Department of Physiology and Biophysics, University of Louisville, Louisville, Kentucky, USA
| | - Eleanor Lederer
- Department of Medicine, University of Louisville, Louisville, Kentucky, USA
- Department of Physiology and Biophysics, University of Louisville, Louisville, Kentucky, USA
- Robley Rex VA Medical Center, University of Louisville, Louisville, Kentucky, USA
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19
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Chan ASM, Clairfeuille T, Landao-Bassonga E, Kinna G, Ng PY, Loo LS, Cheng TS, Zheng M, Hong W, Teasdale RD, Collins BM, Pavlos NJ. Sorting nexin 27 couples PTHR trafficking to retromer for signal regulation in osteoblasts during bone growth. Mol Biol Cell 2016; 27:1367-82. [PMID: 26912788 PMCID: PMC4831889 DOI: 10.1091/mbc.e15-12-0851] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/10/2016] [Indexed: 12/26/2022] Open
Abstract
The parathyroid hormone 1 receptor (PTHR) is central to the process of bone formation and remodeling. PTHR signaling requires receptor internalization into endosomes, which is then terminated by recycling or degradation. Here we show that sorting nexin 27 (SNX27) functions as an adaptor that couples PTHR to the retromer trafficking complex. SNX27 binds directly to the C-terminal PDZ-binding motif of PTHR, wiring it to retromer for endosomal sorting. The structure of SNX27 bound to the PTHR motif reveals a high-affinity interface involving conserved electrostatic interactions. Mechanistically, depletion of SNX27 or retromer augments intracellular PTHR signaling in endosomes. Osteoblasts genetically lacking SNX27 show similar disruptions in PTHR signaling and greatly reduced capacity for bone mineralization, contributing to profound skeletal deficits in SNX27-knockout mice. Taken together, our data support a critical role for SNX27-retromer mediated transport of PTHR in normal bone development.
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Affiliation(s)
- Audrey S M Chan
- Cellular Orthopaedic Laboratory, School of Surgery, University of Western Australia, Nedlands 6009, Australia
| | - Thomas Clairfeuille
- Institute for Molecular Bioscience, University of Queensland, St. Lucia 4072, Australia
| | - Euphemie Landao-Bassonga
- Cellular Orthopaedic Laboratory, School of Surgery, University of Western Australia, Nedlands 6009, Australia
| | - Genevieve Kinna
- Institute for Molecular Bioscience, University of Queensland, St. Lucia 4072, Australia
| | - Pei Ying Ng
- Cellular Orthopaedic Laboratory, School of Surgery, University of Western Australia, Nedlands 6009, Australia
| | - Li Shen Loo
- Institute of Molecular and Cell Biology, A*STAR, Singapore 138673
| | - Tak Sum Cheng
- Cellular Orthopaedic Laboratory, School of Surgery, University of Western Australia, Nedlands 6009, Australia
| | - Minghao Zheng
- Cellular Orthopaedic Laboratory, School of Surgery, University of Western Australia, Nedlands 6009, Australia
| | - Wanjin Hong
- Institute of Molecular and Cell Biology, A*STAR, Singapore 138673
| | - Rohan D Teasdale
- Institute for Molecular Bioscience, University of Queensland, St. Lucia 4072, Australia
| | - Brett M Collins
- Institute for Molecular Bioscience, University of Queensland, St. Lucia 4072, Australia
| | - Nathan J Pavlos
- Cellular Orthopaedic Laboratory, School of Surgery, University of Western Australia, Nedlands 6009, Australia
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20
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Pupo AS, Duarte DA, Lima V, Teixeira LB, Parreiras-E-Silva LT, Costa-Neto CM. Recent updates on GPCR biased agonism. Pharmacol Res 2016; 112:49-57. [PMID: 26836887 DOI: 10.1016/j.phrs.2016.01.031] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 01/27/2016] [Accepted: 01/28/2016] [Indexed: 12/20/2022]
Abstract
G protein-coupled receptors (GPCRs) are the most important targets for drug discovery and not surprisingly ∼40% of all drugs currently in the market act on these receptors. Currently, one of the most active areas in GPCRs signaling is biased agonism, a phenomenon that occurs when a given ligand is able to preferentially activate one (or some) of the possible signaling pathways. In this review, we highlight the most recent findings about biased agonism, including an extension of this concept to intracellular signaling, allosterism, strategies for assessment and interpretation, and perspectives of therapeutic applications for biased agonists.
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Affiliation(s)
- André S Pupo
- Department of Pharmacology, Instituto de Biociências, UNESP, Botucatu, SP, Brazil.
| | - Diego A Duarte
- Department of Biochemistry and Immunology, Faculty of Medicine at Ribeirão Preto, University of São Paulo, 14049-900 Ribeirão Preto, SP, Brazil
| | - Vanessa Lima
- Department of Pharmacology, Instituto de Biociências, UNESP, Botucatu, SP, Brazil; Department of Biochemistry and Immunology, Faculty of Medicine at Ribeirão Preto, University of São Paulo, 14049-900 Ribeirão Preto, SP, Brazil
| | - Larissa B Teixeira
- Department of Biochemistry and Immunology, Faculty of Medicine at Ribeirão Preto, University of São Paulo, 14049-900 Ribeirão Preto, SP, Brazil
| | - Lucas T Parreiras-E-Silva
- Department of Biochemistry and Immunology, Faculty of Medicine at Ribeirão Preto, University of São Paulo, 14049-900 Ribeirão Preto, SP, Brazil
| | - Claudio M Costa-Neto
- Department of Biochemistry and Immunology, Faculty of Medicine at Ribeirão Preto, University of São Paulo, 14049-900 Ribeirão Preto, SP, Brazil.
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21
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Hattersley G, Dean T, Corbin BA, Bahar H, Gardella TJ. Binding Selectivity of Abaloparatide for PTH-Type-1-Receptor Conformations and Effects on Downstream Signaling. Endocrinology 2016; 157:141-9. [PMID: 26562265 PMCID: PMC4701881 DOI: 10.1210/en.2015-1726] [Citation(s) in RCA: 186] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The PTH receptor type 1 (PTHR1) mediates the actions of two endogenous polypeptide ligands, PTH and PTHrP, and thereby plays key roles in bone biology. Based on its capacity to stimulate bone formation, the peptide fragment PTH (1-34) is currently in use as therapy for osteoporosis. Abaloparatide (ABL) is a novel synthetic analog of human PTHrP (1-34) that holds promise as a new osteoporosis therapy, as studies in animals suggest that it can stimulate bone formation with less of the accompanying bone resorption and hypercalcemic effects that can occur with PTH (1-34). Recent studies in vitro suggest that certain PTH or PTHrP ligand analogs can distinguish between two high-affinity PTHR1 conformations, R(0) and RG, and that efficient binding to R(0) results in prolonged signaling responses in cells and prolonged calcemic responses in animals, whereas selective binding to RG results in more transient responses. As intermittent PTH ligand action is known to favor the bone-formation response, whereas continuous ligand action favors the net bone-resorption/calcemic response, we hypothesized that ABL binds more selectively to the RG vs the R(0) PTHR1 conformation than does PTH (1-34), and thus induces more transient signaling responses in cells. We show that ABL indeed binds with greater selectivity to the RG conformation than does PTH (1-34), and as a result of this RG bias, ABL mediates more transient cAMP responses in PTHR1-expressing cells. The findings provide a plausible mechanism (ie, transient signaling via RG-selective binding) that can help account for the favorable anabolic effects that ABL has on bone.
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Affiliation(s)
- Gary Hattersley
- Radius Health Inc (G.H., H.B.), Waltham, Massachusetts 02451; and Endocrine Unit (T.D., B.A.C., T.J.G.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
| | - Thomas Dean
- Radius Health Inc (G.H., H.B.), Waltham, Massachusetts 02451; and Endocrine Unit (T.D., B.A.C., T.J.G.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
| | - Braden A Corbin
- Radius Health Inc (G.H., H.B.), Waltham, Massachusetts 02451; and Endocrine Unit (T.D., B.A.C., T.J.G.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
| | - Hila Bahar
- Radius Health Inc (G.H., H.B.), Waltham, Massachusetts 02451; and Endocrine Unit (T.D., B.A.C., T.J.G.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
| | - Thomas J Gardella
- Radius Health Inc (G.H., H.B.), Waltham, Massachusetts 02451; and Endocrine Unit (T.D., B.A.C., T.J.G.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
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22
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Cheloha RW, Gellman SH, Vilardaga JP, Gardella TJ. PTH receptor-1 signalling-mechanistic insights and therapeutic prospects. Nat Rev Endocrinol 2015; 11:712-24. [PMID: 26303600 PMCID: PMC4651712 DOI: 10.1038/nrendo.2015.139] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Parathyroid hormone/parathyroid hormone-related protein receptor (PTH/PTHrP type 1 receptor; commonly known as PTHR1) is a family B G-protein-coupled receptor (GPCR) that regulates skeletal development, bone turnover and mineral ion homeostasis. PTHR1 transduces stimuli from PTH and PTHrP into the interior of target cells to promote diverse biochemical responses. Evaluation of the signalling properties of structurally modified PTHR1 ligands has helped to elucidate determinants of receptor function and mechanisms of downstream cellular and physiological responses. Analysis of PTHR1 responses induced by structurally modified ligands suggests that PTHR1 can continue to signal through a G-protein-mediated pathway within endosomes. Such findings challenge the longstanding paradigm in GPCR biology that the receptor is transiently activated at the cell membrane, followed by rapid deactivation and receptor internalization. Evaluation of structurally modified PTHR1 ligands has further led to the identification of ligand analogues that differ from PTH or PTHrP in the type, strength and duration of responses induced at the receptor, cellular and organism levels. These modified ligands, and the biochemical principles revealed through their use, might facilitate an improved understanding of PTHR1 function in vivo and enable the treatment of disorders resulting from defects in PTHR1 signalling. This Review discusses current understanding of PTHR1 modes of action and how these findings might be applied in future therapeutic agents.
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Affiliation(s)
- Ross W Cheloha
- Department of Chemistry, 1101 University Avenue, University of Wisconsin, Madison, WI 53706, USA
| | - Samuel H Gellman
- Department of Chemistry, 1101 University Avenue, University of Wisconsin, Madison, WI 53706, USA
| | - Jean-Pierre Vilardaga
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, 200 Lothrop Street, Pittsburgh, PA 15213, USA
| | - Thomas J Gardella
- Endocrine Unit, Massachusetts General Hospital, 50 Blossom Street, Boston, MA 02114, USA
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23
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Gardella TJ, Vilardaga JP. International Union of Basic and Clinical Pharmacology. XCIII. The parathyroid hormone receptors--family B G protein-coupled receptors. Pharmacol Rev 2015; 67:310-37. [PMID: 25713287 DOI: 10.1124/pr.114.009464] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The type-1 parathyroid hormone receptor (PTHR1) is a family B G protein-coupled receptor (GPCR) that mediates the actions of two polypeptide ligands; parathyroid hormone (PTH), an endocrine hormone that regulates the levels of calcium and inorganic phosphate in the blood by acting on bone and kidney, and PTH-related protein (PTHrP), a paracrine-factor that regulates cell differentiation and proliferation programs in developing bone and other tissues. The type-2 parathyroid hormone receptor (PTHR2) binds a peptide ligand, called tuberoinfundibular peptide-39 (TIP39), and while the biologic role of the PTHR2/TIP39 system is not as defined as that of the PTHR1, it likely plays a role in the central nervous system as well as in spermatogenesis. Mechanisms of action at these receptors have been explored through a variety of pharmacological and biochemical approaches, and the data obtained support a basic "two-site" mode of ligand binding now thought to be used by each of the family B peptide hormone GPCRs. Recent crystallographic studies on the family B GPCRs are providing new insights that help to further refine the specifics of the overall receptor architecture and modes of ligand docking. One intriguing pharmacological finding for the PTHR1 is that it can form surprisingly stable complexes with certain PTH/PTHrP ligand analogs and thereby mediate markedly prolonged cell signaling responses that persist even when the bulk of the complexes are found in internalized vesicles. The PTHR1 thus appears to be able to activate the Gα(s)/cAMP pathway not only from the plasma membrane but also from the endosomal domain. The cumulative findings could have an impact on efforts to develop new drug therapies for the PTH receptors.
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Affiliation(s)
- Thomas J Gardella
- Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts (T.J.G.); and Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania (J.-P.V.)
| | - Jean-Pierre Vilardaga
- Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts (T.J.G.); and Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania (J.-P.V.)
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Lee S, Mannstadt M, Guo J, Kim SM, Yi HS, Khatri A, Dean T, Okazaki M, Gardella TJ, Jüppner H. A Homozygous [Cys25]PTH(1-84) Mutation That Impairs PTH/PTHrP Receptor Activation Defines a Novel Form of Hypoparathyroidism. J Bone Miner Res 2015; 30:1803-13. [PMID: 25891861 PMCID: PMC4580526 DOI: 10.1002/jbmr.2532] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 03/30/2015] [Accepted: 04/13/2015] [Indexed: 11/10/2022]
Abstract
Hypocalcemia and hyperphosphatemia are encountered in idiopathic hypoparathyroidism (IHP) and pseudohypoparathyroidism type Ib (PHP1B). In contrast to PHP1B, which is caused by resistance toward parathyroid hormone (PTH), the genetic defects leading to IHP impair production of this important regulator of mineral ion homeostasis. So far, only five PTH mutations were shown to cause IHP, each of which is located in the hormone's pre-pro leader segment and thus impair hormone secretion. In three siblings affected by IHP, we now identified a homozygous arginine-to-cysteine mutation at position 25 (R25C) of the mature PTH(1-84) polypeptide; heterozygous family members are healthy. Depending on the assay used for evaluating these patients, plasma PTH levels were either low or profoundly elevated, thus leading to ambiguities regarding the underlying diagnosis, namely IHP or PHP1B. Consistent with increased PTH levels, recombinant [Cys25]PTH(1-84) and wild-type PTH(1-84) were secreted equally well by transfected COS-7 cells. However, synthetic [Cys25]PTH(1-34) was found to have a lower binding affinity for the PTH receptor type-1 (PTH1R) than PTH(1-34) and consequently a lower efficiency for stimulating cAMP formation in cells expressing this receptor. Consistent with these in vitro findings, long-term infusion of [Cys25]PTH(1-34) resulted only in minimal calcemic and phosphaturic responses, despite readily detectable levels of [Cys25]PTH(1-34) in plasma. The mineral ion abnormalities observed in the three IHP patients are thus most likely caused by the inherited homozygous missense PTH mutation, which reduces bioactivity of the secreted hormone. Based on these findings, screening for PTH(1-84) mutations should be considered when clinical and laboratory findings are consistent with PHP1B, but GNAS methylation changes have been excluded. Differentiating between IHP and PHP1B has considerable implications for genetic counseling, therapy, and long-term outcome because treatment of IHP patients with inappropriately high doses of active vitamin D and calcium can contribute to development of nephrocalcinosis and chronic kidney disease.
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Affiliation(s)
- Sihoon Lee
- Department of Internal Medicine and Laboratory of Molecular Endocrinology, Gachon University School of Medicine, Incheon, South Korea
| | - Michael Mannstadt
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Jun Guo
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Seul Min Kim
- Department of Internal Medicine and Laboratory of Molecular Endocrinology, Gachon University School of Medicine, Incheon, South Korea
| | - Hyon-Seung Yi
- Department of Internal Medicine and Laboratory of Molecular Endocrinology, Gachon University School of Medicine, Incheon, South Korea
| | - Ashok Khatri
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Thomas Dean
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Makoto Okazaki
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Thomas J Gardella
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Harald Jüppner
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.,Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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Sarma T, Koutsouris A, Yu JZ, Krbanjevic A, Hope TJ, Rasenick MM. Activation of microtubule dynamics increases neuronal growth via the nerve growth factor (NGF)- and Gαs-mediated signaling pathways. J Biol Chem 2015; 290:10045-56. [PMID: 25691569 DOI: 10.1074/jbc.m114.630632] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Indexed: 01/19/2023] Open
Abstract
Signals that activate the G protein Gαs and promote neuronal differentiation evoke Gαs internalization in rat pheochromocytoma (PC12) cells. These agents also significantly increase Gαs association with microtubules, resulting in an increase in microtubule dynamics because of the activation of tubulin GTPase by Gαs. To determine the function of Gαs/microtubule association in neuronal development, we used real-time trafficking of a GFP-Gαs fusion protein. GFP-Gαs concentrates at the distal end of the neurites in differentiated living PC12 cells as well as in cultured hippocampal neurons. Gαs translocates to specialized membrane compartments at tips of growing neurites. A dominant-negative Gα chimera that interferes with Gαs binding to tubulin and activation of tubulin GTPase attenuates neurite elongation and neurite number both in PC12 cells and primary hippocampal neurons. This effect is greatest on differentiation induced by activated Gαs. Together, these data suggest that activated Gαs translocates from the plasma membrane and, through interaction with tubulin/microtubules in the cytosol, is important for neurite formation, development, and outgrowth. Characterization of neuronal G protein dynamics and their contribution to microtubule dynamics is important for understanding the molecular mechanisms by which G protein-coupled receptor signaling orchestrates neuronal growth and differentiation.
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Affiliation(s)
- Tulika Sarma
- From the Department of Physiology and Biophysics and
| | | | - Jiang Zhu Yu
- From the Department of Physiology and Biophysics and
| | - Aleksandar Krbanjevic
- From the Department of Physiology and Biophysics and Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612
| | - Thomas J Hope
- the Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, and
| | - Mark M Rasenick
- From the Department of Physiology and Biophysics and Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, the Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois 60612
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Tsvetanova NG, Irannejad R, von Zastrow M. G protein-coupled receptor (GPCR) signaling via heterotrimeric G proteins from endosomes. J Biol Chem 2015; 290:6689-96. [PMID: 25605726 DOI: 10.1074/jbc.r114.617951] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Some G protein-coupled receptors (GPCRs), in addition to activating heterotrimeric G proteins in the plasma membrane, appear to elicit a "second wave" of G protein activation after ligand-induced internalization. We briefly summarize evidence supporting this view and then discuss what is presently known about the functional significance of GPCR-G protein activation in endosomes. Endosomal activation can shape the cellular response temporally by prolonging its overall duration, and may shape the response spatially by moving the location of intracellular second messenger production relative to effectors.
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Affiliation(s)
| | | | - Mark von Zastrow
- From the Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California 94158
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Abstract
It has been widely assumed that the production of the ubiquitous second messenger cyclic AMP, which is mediated by cell surface G protein–coupled receptors (GPCRs), and its termination take place exclusively at the plasma membrane. Recent studies reveal that diverse GPCRs do not always follow this conventional paradigm. In the new model, GPCRs mediate G-protein signaling not only from the plasma membrane but also from endosomal membranes. This model proposes that following ligand binding and activation, cell surface GPCRs internalize and redistribute into early endosomes, where trimeric G protein signaling can be maintained for an extended period of time. This Perspective discusses the molecular and cellular mechanistic subtleties as well as the physiological consequences of this unexpected process, which is considerably changing how we think about GPCR signaling and regulation and how we study drugs that target this receptor family.
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Polyzos SA, Makras P, Efstathiadou Z, Anastasilakis AD. Investigational parathyroid hormone receptor analogs for the treatment of osteoporosis. Expert Opin Investig Drugs 2014; 24:145-57. [PMID: 25316089 DOI: 10.1517/13543784.2015.973021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
INTRODUCTION Intermittent parathyroid hormone (PTH) administration, acting through multiple signaling pathways, exerts an osteoanabolic effect on the skeleton that surpasses the effect of other antiosteoporotic agents. However, its efficacy is limited by the coupling effect and relatively common adverse events. Thus, the development of more sophisticated PTH receptor analogs seems imperative. AREAS COVERED In this review, the authors summarize the role of PTH signaling pathway in bone remodeling. The authors also summarize investigational analogs targeting this pathway, which may be potential treatments for osteoporosis. EXPERT OPINION β-arrestins are multifunctional cytoplasmic molecules that are decisive for regulating intracellular PTH signaling. Recently, in preclinical studies, arrestin analogs have achieved the anabolic bone effect of PTH without an accompanying increase in bone resorption. However, it is not yet known whether these analogs have adverse effects and there are no clinical data for their efficacy to date. On the other hand, several molecules derived either from PTH and PTH-related protein (PTHrP) molecules have been developed. Alternative routes of PTH 1 - 34 delivery (oral, transdermal), the PTH analog ostabolin and the N-terminal PTHrP analogs PTHrP 1 - 36 and abaloparatide, have recently been or are currently being tested in clinical trials and are more likely to become available for use in the near future.
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Affiliation(s)
- Stergios A Polyzos
- Harvard Medical School, Beth Israel Deaconess Medical Center, Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine , Boston, MA , USA
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Charest-Morin X, Fortin JP, Lodge R, Allaeys I, Poubelle PE, Marceau F. A tagged parathyroid hormone derivative as a carrier of antibody cargoes transported by the G protein coupled PTH1 receptor. Peptides 2014; 60:71-9. [PMID: 25128082 DOI: 10.1016/j.peptides.2014.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/01/2014] [Accepted: 08/01/2014] [Indexed: 01/24/2023]
Abstract
Based on the known fact that the parathyroid hormone (PTH) might be extended at its C-terminus with biotechnological protein cargoes, a vector directing the secretion of PTH1-84 C-terminally fused with the antigenic epitope myc (PTH-myc) was exploited. The functional properties and potential of this analog for imaging PTH1R-expressing cells were examined. The PTH-myc construct was recombinantly produced as a conditioned medium (CM) of transfected HEK 293a cells (typical concentrations of 187nM estimated with ELISAs for PTH). PTH-myc CM induced cyclic AMP formations (10min), with a minor loss of potency relative to authentic PTH1-84, and c-Fos expression (1-3h). Treatment of recipient HEK 293a cells transiently expressing PTH1R with PTH-myc CM (supplemented with a fluorescent monoclonal anti-myc tag antibody, either 4A6 or 9E10) allowed the labeling of endosomal structures positive for Rab5 and/or for β-arrestin1 (microscopy, cytofluorometry). Authentic PTH was inactive in this respect, ruling out a non-specific form of endocytosis like pinocytosis. Using a horseradish peroxidase-conjugated secondary antibody, the endocytosis of the PTH-myc-based antibody complex by endogenous PTH1R was evidenced in MG-63 osteoblastoid cells. The secreted construct PTH-myc represents a bona fide agonist that supports the feasibility of transporting cargoes of considerable molecular weight inside cells using arrestin and Rab5-mediated PTH1R endocytosis. PTH-myc is also transported into cells that express PTH1R at a physiological level. Such tagged peptide hormones may be part of a cancer chemotherapy scheme exploiting a modular cytotoxic secondary antibody and the receptor repertoire expressed in a given tumor.
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Affiliation(s)
- Xavier Charest-Morin
- Centre de recherche en Rhumatologie et Immunologie, CHU de Québec, Québec, QC, Canada G1V 4G2
| | - Jean-Philippe Fortin
- Pfizer's Cardiovascular and Metabolic Diseases Research Unit, Cambridge, MA 02139, USA
| | - Robert Lodge
- Laboratory of Human Retrovirology, Institut de recherches cliniques de Montréal, Montreal, QC, Canada H2W 1R7
| | - Isabelle Allaeys
- Centre de recherche en Rhumatologie et Immunologie, CHU de Québec, Québec, QC, Canada G1V 4G2
| | - Patrice E Poubelle
- Centre de recherche en Rhumatologie et Immunologie, CHU de Québec, Québec, QC, Canada G1V 4G2
| | - François Marceau
- Centre de recherche en Rhumatologie et Immunologie, CHU de Québec, Québec, QC, Canada G1V 4G2.
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Gidon A, Al-Bataineh MM, Jean-Alphonse FG, Stevenson H, Watanabe T, Louet C, Khatri A, Calero G, Pastor-Soler NM, Gardella TJ, Vilardaga JP. Endosomal GPCR signaling turned off by negative feedback actions of PKA and v-ATPase. Nat Chem Biol 2014; 10:707-9. [PMID: 25064832 PMCID: PMC4138287 DOI: 10.1038/nchembio.1589] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 06/13/2014] [Indexed: 12/13/2022]
Abstract
The PTH receptor is to our knowledge one of the first G protein-coupled receptor (GPCR) found to sustain cAMP signaling after internalization of the ligand-receptor complex in endosomes. This unexpected model is adding a new dimension on how we think about GPCR signaling, but its mechanism is incompletely understood. We report here that endosomal acidification mediated by the PKA action on the v-ATPase provides a negative feedback mechanism by which endosomal receptor signaling is turned off.
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Affiliation(s)
- Alexandre Gidon
- Laboratory for GPCR Biology, Department of Pharmacology & Chemical Biology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15261, USA
| | - Mohammad M. Al-Bataineh
- Renal-Electrolyte Division, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15261, USA
| | - Frederic G. Jean-Alphonse
- Laboratory for GPCR Biology, Department of Pharmacology & Chemical Biology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15261, USA
| | - Hilary Stevenson
- Department of Structural Biology Department of Medicine, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15261, USA
| | - Tomoyuki Watanabe
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 0114, USA
| | - Claire Louet
- Laboratory for GPCR Biology, Department of Pharmacology & Chemical Biology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15261, USA
| | - Ashok Khatri
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 0114, USA
| | - Guillermo Calero
- Department of Structural Biology Department of Medicine, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15261, USA
| | - Núria M. Pastor-Soler
- Renal-Electrolyte Division, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15261, USA
| | - Thomas J. Gardella
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 0114, USA
| | - Jean-Pierre Vilardaga
- Laboratory for GPCR Biology, Department of Pharmacology & Chemical Biology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15261, USA
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Mozar A, Kondegowda NG, Pollack I, Fenutria R, Vasavada RC. The Role of PTHrP in Pancreatic Beta-Cells and Implications for Diabetes Pathophysiology and Treatment. Clin Rev Bone Miner Metab 2014. [DOI: 10.1007/s12018-014-9168-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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32
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Abstract
Teeth are mineralized organs composed of three unique hard tissues, enamel, dentin, and cementum, and supported by the surrounding alveolar bone. Although odontogenesis differs from osteogenesis in several respects, tooth mineralization is susceptible to similar developmental failures as bone. Here we discuss conditions fitting under the umbrella of rickets, which traditionally referred to skeletal disease associated with vitamin D deficiency but has been more recently expanded to include newly identified factors involved in endocrine regulation of vitamin D, phosphate, and calcium, including phosphate-regulating endopeptidase homolog, X-linked, fibroblast growth factor 23, and dentin matrix protein 1. Systemic mineral metabolism intersects with local regulation of mineralization, and factors including tissue nonspecific alkaline phosphatase are necessary for proper mineralization, where rickets can result from loss of activity of tissue nonspecific alkaline phosphatase. Individuals suffering from rickets often bear the additional burden of a defective dentition, and transgenic mouse models have aided in understanding the nature and mechanisms involved in tooth defects, which may or may not parallel rachitic bone defects. This report reviews dental effects of the range of rachitic disorders, including discussion of etiologies of hereditary forms of rickets, a survey of resulting bone and tooth mineralization disorders, and a discussion of mechanisms, known and hypothesized, involved in the observed dental pathologies. Descriptions of human pathology are augmented by analysis of transgenic mouse models, and new interpretations are brought to bear on questions of how teeth are affected under conditions of rickets. In short, the rachitic tooth will be revealed.
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Affiliation(s)
- Brian L Foster
- National Institute for Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland 20892
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33
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Abstract
It is now established that agonists do not uniformly activate pleiotropic signaling mechanisms initiated by receptors but rather can bias signals according to the unique receptor conformations they stabilize. One of the important emerging signaling systems where this can occur is through β-arrestin. This chapter discusses biased signaling where emphasis or de-emphasis of β-arrestin signaling is postulated (or been shown) to be beneficial. The chapter specifically focuses on methods to quantify biased effects; these methods furnish scales that can be used in the process of optimizing biased agonism (and antagonism) for therapeutic benefit. Specifically, methods to derive ΔΔLog(τ/K A) or ΔΔLog(Relative Activity) values are described to do this.
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Affiliation(s)
- Terry Kenakin
- Department of Pharmacology, University of North Carolina School of Medicine, 120 Mason Farm Road, Room 4042, Genetic Medicine Building, CB# 7365, Chapel Hill, NC, 27599-7365, USA,
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34
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Charest-Morin X, Fortin JP, Bawolak MT, Lodge R, Marceau F. Green fluorescent protein fused to peptide agonists of two dissimilar G protein-coupled receptors: novel ligands of the bradykinin B2 (rhodopsin family) receptor and parathyroid hormone PTH1 (secretin family) receptor. Pharmacol Res Perspect 2013; 1:e00004. [PMID: 25505558 PMCID: PMC4184569 DOI: 10.1002/prp2.4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 07/26/2013] [Accepted: 08/02/2013] [Indexed: 01/27/2023] Open
Abstract
We hypothesized that peptide hormone sequences that stimulate and internalize G protein-coupled receptors (GPCRs) could be prolonged with a functional protein cargo. To verify this, we have selected two widely different pairs of peptide hormones and GPCRs that nevertheless share agonist-induced arrestin-mediated internalization. For the parathyroid hormone (PTH) PTH1 receptor (PTH1R) and the bradykinin (BK) B2 receptor (B2R), we have designed fusion proteins of the agonists PTH1-34 and maximakinin (MK, a BK homologue) with the enhanced green fluorescent protein (EGFP), thus producing candidate high molecular weight ligands. According to docking models of each hormone to its receptor, EGFP was fused either at the N-terminus (MK) or C-terminus (PTH1-34) of the ligand; the last construction is also secretable due to inclusion of the preproinsulin signal peptide and has been produced as a conditioned medium. EGFP-MK has been produced as a lysate of transfected cells. Using an enzyme-linked immunosorbent assay (ELISA) for GFP, average concentrations of 1.5 and 1670 nmol/L, respectively, of ligand were found in these preparations. The functional properties and potential of these analogs for imaging receptor-expressing cells were examined. Microscopic and cytofluorometric evidence of specific binding and internalization of both fusion proteins was obtained using recipient HEK 293a cells that expressed the cognate recombinant receptor. Endosomal colocalization studies were conducted (Rab5, Rab7, β-arrestin1). Evidence of agonist signaling was obtained (expression of c-Fos, cyclic AMP responsive element (CRE) reporter gene for PTH1-34-EGFP). The constructs PTH1-34-EGFP and EGFP-MK represent bona fide agonists that support the feasibility of transporting protein cargoes inside cells using GPCRs.
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Affiliation(s)
- Xavier Charest-Morin
- Centre de recherche en rhumatologie et immunologie, CHU de Québec, Université Laval Québec, Canada, G1V 4G2
| | - Jean-Philippe Fortin
- Pfizer's Cardiovascular and Metabolic Diseases Research Unit Cambridge, Massachusetts, 02139
| | - Marie-Thérèse Bawolak
- Centre de recherche en rhumatologie et immunologie, CHU de Québec, Université Laval Québec, Canada, G1V 4G2
| | - Robert Lodge
- Laboratory of Human Retrovirology, Institut de recherches cliniques de Montréal Montreal, Québec, Canada, H2W 1R7
| | - François Marceau
- Centre de recherche en rhumatologie et immunologie, CHU de Québec, Université Laval Québec, Canada, G1V 4G2
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Feinstein TN, Yui N, Webber MJ, Wehbi VL, Stevenson HP, King JD, Hallows KR, Brown D, Bouley R, Vilardaga JP. Noncanonical control of vasopressin receptor type 2 signaling by retromer and arrestin. J Biol Chem 2013; 288:27849-60. [PMID: 23935101 DOI: 10.1074/jbc.m112.445098] [Citation(s) in RCA: 152] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The vasopressin type 2 receptor (V2R) is a critical G protein-coupled receptor (GPCR) for vertebrate physiology, including the balance of water and sodium ions. It is unclear how its two native hormones, vasopressin (VP) and oxytocin (OT), both stimulate the same cAMP/PKA pathway yet produce divergent antinatriuretic and antidiuretic effects that are either strong (VP) or weak (OT). Here, we present a new mechanism that differentiates the action of VP and OT on V2R signaling. We found that vasopressin, as opposed to OT, continued to generate cAMP and promote PKA activation for prolonged periods after ligand washout and receptor internalization in endosomes. Contrary to the classical model of arrestin-mediated GPCR desensitization, arrestins bind the VP-V2R complex yet extend rather than shorten the generation of cAMP. Signaling is instead turned off by the endosomal retromer complex. We propose that this mechanism explains how VP sustains water and Na(+) transport in renal collecting duct cells. Together with recent work on the parathyroid hormone receptor, these data support the existence of a novel "noncanonical" regulatory pathway for GPCR activation and response termination, via the sequential action of β-arrestin and the retromer complex.
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Affiliation(s)
- Timothy N Feinstein
- From the Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
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36
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Alonso V, Friedman PA. Minireview: ubiquitination-regulated G protein-coupled receptor signaling and trafficking. Mol Endocrinol 2013; 27:558-72. [PMID: 23471539 DOI: 10.1210/me.2012-1404] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are the largest and most diverse superfamily of membrane proteins and mediate most cellular responses to hormones and neurotransmitters. Posttranslational modifications are considered the main regulators of all GPCRs. In addition to phosphorylation, glycosylation, and palmitoylation, increasing evidence as reviewed here reveals that ubiquitination also regulates the magnitude and temporospatial aspects of GPCR signaling. Posttranslational protein modification by ubiquitin is a key molecular mechanism governing proteins degradation. Ubiquitination mediates the covalent conjugation of ubiquitin, a highly conserved polypeptide of 76 amino acids, to protein substrates. This process is catalyzed by 3 enzymes acting in tandem: an E1, ubiquitin-activating enzyme; an E2, ubiquitin-carrying enzyme; and an E3, ubiquitin ligase. Ubiquitination is counteracted by deubiquitinating enzymes that deconjugate ubiquitin-modified proteins and rescue the substrate from proteasomal degradation. Although ubiquitination is known to target many GPCRs for lysosomal or proteasomal degradation, emerging findings define novel roles for the basal status of ubiquitination and for rapid deubiquitination and transubiquitination controlling cell surface expression and cellular responsiveness of some GPCRs. In this review, we highlight the classical and novel roles of ubiquitin in the regulation of GPCR function, signaling, and trafficking.
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Affiliation(s)
- Verónica Alonso
- Institute of Applied Molecular Medicine, San Pablo-CEU University School of Medicine, Madrid, 28668, Spain
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37
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Leonard AP, Appleton KM, Luttrell LM, Peterson YK. A high-content, live-cell, and real-time approach to the quantitation of ligand-induced β-Arrestin2 and Class A/Class B GPCR mobilization. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2013; 19:150-170. [PMID: 23351552 PMCID: PMC4169994 DOI: 10.1017/s1431927612014067] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report the development of a method to analyze receptor and β-arrestin2 mobilization between Class A and B GPCRs via time-resolved fluorescent microscopy coupled with semiautomated high-content multiparametric analysis. Using transiently expressed, tagged β2-adrenergic receptor (β₂-AR) or parathyroid hormone receptor type 1 (PTH₁R), we quantified trafficking of the receptors along with the mobilization and colocalization of coexpressed tagged β-arrestin2. This classification system allows for exclusion of cells with nonoptimal characteristics and calculation of multiple morphological and spatial parameters including receptor endosome formation, β-arrestin mobilization, colocalization, areas, and shape. Stimulated Class A and B receptors demonstrate dramatically different patterns with regard to β-arrestin interactions. The method provides high kinetic resolution measurement of receptor translocation, which allows for the identification of the fleeting β-arrestin interaction found with β₂-AR agonist stimulation, in contrast to stronger mobilization and receptor colocalization with agonist stimulation of the PTH₁R. Though especially appropriate for receptor kinetic studies, this method is generalizable to any dual fluorescence probe system in which quantification of object formation and movement is desired. These methodologies allow for quantitative, unbiased measurement of microscopy data and are further enhanced by providing real-time kinetics.
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Affiliation(s)
- Anthony P. Leonard
- Medical University of South Carolina, Pharmaceutical and Biomedical Sciences, Charleston, SC 29425, USA
| | - Kathryn M. Appleton
- Medical University of South Carolina, Pharmaceutical and Biomedical Sciences, Charleston, SC 29425, USA
| | - Louis M. Luttrell
- Medical University of South Carolina, Medicine, Charleston, SC 29425, USA
| | - Yuri K. Peterson
- Medical University of South Carolina, Pharmaceutical and Biomedical Sciences, Charleston, SC 29425, USA
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38
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von Zastrow M, Williams JT. Modulating neuromodulation by receptor membrane traffic in the endocytic pathway. Neuron 2012; 76:22-32. [PMID: 23040804 DOI: 10.1016/j.neuron.2012.09.022] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Cellular responsiveness to many neuromodulators is controlled by endocytosis of the transmembrane receptors that transduce their effects. Endocytic membrane trafficking of particular neuromodulator receptors exhibits remarkable diversity and specificity, determined largely by molecular sorting operations that guide receptors at trafficking branchpoints after endocytosis. In this Review, we discuss recent progress in elucidating mechanisms mediating the molecular sorting of neuromodulator receptors in the endocytic pathway. There is emerging evidence that endocytic trafficking of neuromodulator receptors, in addition to influencing longer-term cellular responsiveness under conditions of prolonged or repeated activation, may also affect the acute response. Physiological and pathological consequences of defined receptor trafficking events are only now being elucidated, but it is already apparent that endocytosis of neuromodulator receptors has a significant impact on the actions of therapeutic drugs. The present data also suggest, conversely, that mechanisms of receptor endocytosis and molecular sorting may themselves represent promising targets for therapeutic manipulation.
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Affiliation(s)
- Mark von Zastrow
- Department of Psychiatry, University of California at San Francisco, San Francisco, CA 94158, USA.
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