1
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Walker V. The Intricacies of Renal Phosphate Reabsorption-An Overview. Int J Mol Sci 2024; 25:4684. [PMID: 38731904 PMCID: PMC11083860 DOI: 10.3390/ijms25094684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/17/2024] [Accepted: 04/19/2024] [Indexed: 05/13/2024] Open
Abstract
To maintain an optimal body content of phosphorus throughout postnatal life, variable phosphate absorption from food must be finely matched with urinary excretion. This amazing feat is accomplished through synchronised phosphate transport by myriads of ciliated cells lining the renal proximal tubules. These respond in real time to changes in phosphate and composition of the renal filtrate and to hormonal instructions. How they do this has stimulated decades of research. New analytical techniques, coupled with incredible advances in computer technology, have opened new avenues for investigation at a sub-cellular level. There has been a surge of research into different aspects of the process. These have verified long-held beliefs and are also dramatically extending our vision of the intense, integrated, intracellular activity which mediates phosphate absorption. Already, some have indicated new approaches for pharmacological intervention to regulate phosphate in common conditions, including chronic renal failure and osteoporosis, as well as rare inherited biochemical disorders. It is a rapidly evolving field. The aim here is to provide an overview of our current knowledge, to show where it is leading, and where there are uncertainties. Hopefully, this will raise questions and stimulate new ideas for further research.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton S016 6YD, UK
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2
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Maranduca MA, Cozma CT, Clim A, Pinzariu AC, Tudorancea I, Popa IP, Lazar CI, Moscalu R, Filip N, Moscalu M, Constantin M, Scripcariu DV, Serban DN, Serban IL. The Molecular Mechanisms Underlying the Systemic Effects Mediated by Parathormone in the Context of Chronic Kidney Disease. Curr Issues Mol Biol 2024; 46:3877-3905. [PMID: 38785509 PMCID: PMC11120161 DOI: 10.3390/cimb46050241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024] Open
Abstract
Chronic kidney disease (CKD) stands as a prominent non-communicable ailment, significantly impacting life expectancy. Physiopathology stands mainly upon the triangle represented by parathormone-Vitamin D-Fibroblast Growth Factor-23. Parathormone (PTH), the key hormone in mineral homeostasis, is one of the less easily modifiable parameters in CKD; however, it stands as a significant marker for assessing the risk of complications. The updated "trade-off hypothesis" reveals that levels of PTH spike out of the normal range as early as stage G2 CKD, advancing it as a possible determinant of systemic damage. The present review aims to review the effects exhibited by PTH on several organs while linking the molecular mechanisms to the observed actions in the context of CKD. From a diagnostic perspective, PTH is the most reliable and accessible biochemical marker in CKD, but its trend bears a higher significance on a patient's prognosis rather than the absolute value. Classically, PTH acts in a dichotomous manner on bone tissue, maintaining a balance between formation and resorption. Under the uremic conditions of advanced CKD, the altered intestinal microbiota majorly tips the balance towards bone lysis. Probiotic treatment has proven reliable in animal models, but in humans, data are limited. Regarding bone status, persistently high levels of PTH determine a reduction in mineral density and a concurrent increase in fracture risk. Pharmacological manipulation of serum PTH requires appropriate patient selection and monitoring since dangerously low levels of PTH may completely inhibit bone turnover. Moreover, the altered mineral balance extends to the cardiovascular system, promoting vascular calcifications. Lastly, the involvement of PTH in the Renin-Angiotensin-Aldosterone axis highlights the importance of opting for the appropriate pharmacological agent should hypertension develop.
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Affiliation(s)
- Minela Aida Maranduca
- Discipline of Physiology, Department of Morpho-Functional Sciences II, Grigore T. Popa University of Medicine and Pharmacy, 700115 Iasi, Romania; (M.A.M.); (C.T.C.); (A.C.); (A.C.P.); (I.T.); (I.P.P.); (C.I.L.); (D.N.S.); (I.L.S.)
| | - Cristian Tudor Cozma
- Discipline of Physiology, Department of Morpho-Functional Sciences II, Grigore T. Popa University of Medicine and Pharmacy, 700115 Iasi, Romania; (M.A.M.); (C.T.C.); (A.C.); (A.C.P.); (I.T.); (I.P.P.); (C.I.L.); (D.N.S.); (I.L.S.)
| | - Andreea Clim
- Discipline of Physiology, Department of Morpho-Functional Sciences II, Grigore T. Popa University of Medicine and Pharmacy, 700115 Iasi, Romania; (M.A.M.); (C.T.C.); (A.C.); (A.C.P.); (I.T.); (I.P.P.); (C.I.L.); (D.N.S.); (I.L.S.)
| | - Alin Constantin Pinzariu
- Discipline of Physiology, Department of Morpho-Functional Sciences II, Grigore T. Popa University of Medicine and Pharmacy, 700115 Iasi, Romania; (M.A.M.); (C.T.C.); (A.C.); (A.C.P.); (I.T.); (I.P.P.); (C.I.L.); (D.N.S.); (I.L.S.)
| | - Ionut Tudorancea
- Discipline of Physiology, Department of Morpho-Functional Sciences II, Grigore T. Popa University of Medicine and Pharmacy, 700115 Iasi, Romania; (M.A.M.); (C.T.C.); (A.C.); (A.C.P.); (I.T.); (I.P.P.); (C.I.L.); (D.N.S.); (I.L.S.)
| | - Irene Paula Popa
- Discipline of Physiology, Department of Morpho-Functional Sciences II, Grigore T. Popa University of Medicine and Pharmacy, 700115 Iasi, Romania; (M.A.M.); (C.T.C.); (A.C.); (A.C.P.); (I.T.); (I.P.P.); (C.I.L.); (D.N.S.); (I.L.S.)
| | - Cristina Iuliana Lazar
- Discipline of Physiology, Department of Morpho-Functional Sciences II, Grigore T. Popa University of Medicine and Pharmacy, 700115 Iasi, Romania; (M.A.M.); (C.T.C.); (A.C.); (A.C.P.); (I.T.); (I.P.P.); (C.I.L.); (D.N.S.); (I.L.S.)
| | - Roxana Moscalu
- Division of Cell Matrix Biology & Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PL, UK;
| | - Nina Filip
- Discipline of Biochemistry, Department of Morpho-Functional Sciences II, Grigore T. Popa University of Medicine and Pharmacy, 700115 Iasi, Romania;
| | - Mihaela Moscalu
- Department of Preventive Medicine and Interdisciplinarity, Grigore T. Popa University of Medicine and Pharmacy, 700115 Iasi, Romania
| | - Mihai Constantin
- Internal Medicine Department, Faculty of Medicine, Grigore T. Popa University of Medicine and Pharmacy, 700115 Iasi, Romania;
| | - Dragos Viorel Scripcariu
- Department of Surgery, Grigore T. Popa University of Medicine and Pharmacy, 16 University Str., 700115 Iasi, Romania;
| | - Dragomir Nicolae Serban
- Discipline of Physiology, Department of Morpho-Functional Sciences II, Grigore T. Popa University of Medicine and Pharmacy, 700115 Iasi, Romania; (M.A.M.); (C.T.C.); (A.C.); (A.C.P.); (I.T.); (I.P.P.); (C.I.L.); (D.N.S.); (I.L.S.)
| | - Ionela Lacramioara Serban
- Discipline of Physiology, Department of Morpho-Functional Sciences II, Grigore T. Popa University of Medicine and Pharmacy, 700115 Iasi, Romania; (M.A.M.); (C.T.C.); (A.C.); (A.C.P.); (I.T.); (I.P.P.); (C.I.L.); (D.N.S.); (I.L.S.)
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3
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Friedman P, Mamonova T. The molecular sociology of NHERF1 PDZ proteins controlling renal hormone-regulated phosphate transport. Biosci Rep 2024; 44:BSR20231380. [PMID: 38465463 PMCID: PMC10987488 DOI: 10.1042/bsr20231380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 03/07/2024] [Accepted: 03/08/2024] [Indexed: 03/12/2024] Open
Abstract
Parathyroid hormone (PTH) and fibroblast growth factor-23 (FGF23) control extracellular phosphate levels by regulating renal NPT2A-mediated phosphate transport by a process requiring the PDZ scaffold protein NHERF1. NHERF1 possesses two PDZ domains, PDZ1 and PDZ2, with identical core-binding GYGF motifs explicitly recognizing distinct binding partners that play different and specific roles in hormone-regulated phosphate transport. The interaction of PDZ1 and the carboxy-terminal PDZ-binding motif of NPT2A (C-TRL) is required for basal phosphate transport. PDZ2 is a regulatory domain that scaffolds multiple biological targets, including kinases and phosphatases involved in FGF23 and PTH signaling. FGF23 and PTH trigger disassembly of the NHERF1-NPT2A complex through reversible hormone-stimulated phosphorylation with ensuing NPT2A sequestration, down-regulation, and cessation of phosphate absorption. In the absence of NHERF1-NPT2A interaction, inhibition of FGF23 or PTH signaling results in disordered phosphate homeostasis and phosphate wasting. Additional studies are crucial to elucidate how NHERF1 spatiotemporally coordinates cellular partners to regulate extracellular phosphate levels.
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Affiliation(s)
- Peter A. Friedman
- Laboratory for G Protein-Coupled Receptor Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, U.S.A
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, U.S.A
| | - Tatyana Mamonova
- Laboratory for G Protein-Coupled Receptor Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, U.S.A
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4
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Fan M, Geng N, Li X, Yin D, Yang Y, Jiang R, Chen C, Feng N, Liang L, Li X, Luo F, Qi H, Tan Q, Xie Y, Guo F. IRE1α regulates the PTHrP-IHH feedback loop to orchestrate chondrocyte hypertrophy and cartilage mineralization. Genes Dis 2024; 11:464-478. [PMID: 37588212 PMCID: PMC10425753 DOI: 10.1016/j.gendis.2022.11.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 11/07/2022] [Accepted: 11/16/2022] [Indexed: 12/30/2022] Open
Abstract
Cartilage development is controlled by the highly synergistic proliferation and differentiation of growth plate chondrocytes, in which the Indian hedgehog (IHH) and parathyroid hormone-related protein-parathyroid hormone-1 receptor (PTHrP-PTH1R) feedback loop is crucial. The inositol-requiring enzyme 1α/X-box-binding protein-1 spliced (IRE1α/XBP1s) branch of the unfolded protein response (UPR) is essential for normal cartilage development. However, the precise role of ER stress effector IRE1α, encoded by endoplasmic reticulum to nucleus signaling 1 (ERN1), in skeletal development remains unknown. Herein, we reported that loss of IRE1α accelerates chondrocyte hypertrophy and promotes endochondral bone growth. ERN1 acts as a negative regulator of chondrocyte proliferation and differentiation in postnatal growth plates. Its deficiency interrupted PTHrP/PTH1R and IHH homeostasis leading to impaired chondrocyte hypertrophy and differentiation. XBP1s, produced by p-IRE1α-mediated splicing, binds and up-regulates PTH1R and IHH, which coordinate cartilage development. Meanwhile, ER stress cannot be activated normally in ERN1-deficient chondrocytes. In conclusion, ERN1 deficiency accelerates chondrocyte hypertrophy and cartilage mineralization by impairing the homeostasis of the IHH and PTHrP/PTH1R feedback loop and ER stress. ERN1 may have a potential role as a new target for cartilage growth and maturation.
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Affiliation(s)
- Mengtian Fan
- Laboratory of Developmental Biology, Department of Cell Biology and Genetics, School of Basic Medical Science, Chongqing Medical University, Chongqing 400016, China
| | - Nana Geng
- Laboratory of Developmental Biology, Department of Cell Biology and Genetics, School of Basic Medical Science, Chongqing Medical University, Chongqing 400016, China
| | - Xingyue Li
- Laboratory of Developmental Biology, Department of Cell Biology and Genetics, School of Basic Medical Science, Chongqing Medical University, Chongqing 400016, China
| | - Danyang Yin
- Laboratory of Developmental Biology, Department of Cell Biology and Genetics, School of Basic Medical Science, Chongqing Medical University, Chongqing 400016, China
| | - Yuyou Yang
- Laboratory of Developmental Biology, Department of Cell Biology and Genetics, School of Basic Medical Science, Chongqing Medical University, Chongqing 400016, China
| | - Rong Jiang
- Laboratory of Stem Cells and Tissue Engineering, School of Basic Medical Science, Chongqing Medical University, Chongqing 400016, China
| | - Cheng Chen
- Department of Orthopedics, The 1st Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Naibo Feng
- Laboratory of Developmental Biology, Department of Cell Biology and Genetics, School of Basic Medical Science, Chongqing Medical University, Chongqing 400016, China
| | - Li Liang
- Laboratory of Developmental Biology, Department of Cell Biology and Genetics, School of Basic Medical Science, Chongqing Medical University, Chongqing 400016, China
| | - Xiaoli Li
- Laboratory of Developmental Biology, Department of Cell Biology and Genetics, School of Basic Medical Science, Chongqing Medical University, Chongqing 400016, China
| | - Fengtao Luo
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Huabing Qi
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Qiaoyan Tan
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Yangli Xie
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Fengjin Guo
- Laboratory of Developmental Biology, Department of Cell Biology and Genetics, School of Basic Medical Science, Chongqing Medical University, Chongqing 400016, China
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5
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Daly C, Plouffe B. Gα q signalling from endosomes: A new conundrum. Br J Pharmacol 2023. [PMID: 37740273 DOI: 10.1111/bph.16248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/08/2023] [Accepted: 09/13/2023] [Indexed: 09/24/2023] Open
Abstract
G-protein-coupled receptors (GPCRs) constitute the largest family of membrane receptors, and are involved in the transmission of a variety of extracellular stimuli such as hormones, neurotransmitters, light and odorants into intracellular responses. They regulate every aspect of physiology and, for this reason, about one third of all marketed drugs target these receptors. Classically, upon binding to their agonist, GPCRs are thought to activate G-proteins from the plasma membrane and to stop signalling by subsequent desensitisation and endocytosis. However, accumulating evidence indicates that, upon internalisation, some GPCRs can continue to activate G-proteins in endosomes. Importantly, this signalling from endomembranes mediates alternative cellular responses other than signalling at the plasma membrane. Endosomal G-protein signalling and its physiological relevance have been abundantly documented for Gαs - and Gαi -coupled receptors. Recently, some Gαq -coupled receptors have been reported to activate Gαq on endosomes and mediate important cellular processes. However, several questions relative to the series of cellular events required to translate endosomal Gαq activation into cellular responses remain unanswered and constitute a new conundrum. How are these responses in endosomes mediated in the quasi absence of the substrate for the canonical Gαq -activated effector? Is there another effector? Is there another substrate? If so, how does this alternative endosomal effector or substrate produce a downstream signal? This review aims to unravel and discuss these important questions, and proposes possible routes of investigation.
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Affiliation(s)
- Carole Daly
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Bianca Plouffe
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK
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6
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Stewart BZ, Mamonova T, Sneddon WB, Javorsky A, Yang Y, Wang B, Nolin TD, Humbert PO, Friedman PA, Kvansakul M. Scribble scrambles parathyroid hormone receptor interactions to regulate phosphate and vitamin D homeostasis. Proc Natl Acad Sci U S A 2023; 120:e2220851120. [PMID: 37252981 PMCID: PMC10266016 DOI: 10.1073/pnas.2220851120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 03/30/2023] [Indexed: 06/01/2023] Open
Abstract
G protein-coupled receptors, including PTHR, are pivotal for controlling metabolic processes ranging from serum phosphate and vitamin D levels to glucose uptake, and cytoplasmic interactors may modulate their signaling, trafficking, and function. We now show that direct interaction with Scribble, a cell polarity-regulating adaptor protein, modulates PTHR activity. Scribble is a crucial regulator for establishing and developing tissue architecture, and its dysregulation is involved in various disease conditions, including tumor expansion and viral infections. Scribble co-localizes with PTHR at basal and lateral surfaces in polarized cells. Using X-ray crystallography, we show that colocalization is mediated by engaging a short sequence motif at the PTHR C-terminus using Scribble PDZ1 and PDZ3 domain, with binding affinities of 31.7 and 13.4 μM, respectively. Since PTHR controls metabolic functions by actions on renal proximal tubules, we engineered mice to selectively knockout Scribble in proximal tubules. The loss of Scribble impacted serum phosphate and vitamin D levels and caused significant plasma phosphate elevation and increased aggregate vitamin D3 levels, whereas blood glucose levels remained unchanged. Collectively these results identify Scribble as a vital regulator of PTHR-mediated signaling and function. Our findings reveal an unexpected link between renal metabolism and cell polarity signaling.
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Affiliation(s)
- Bryce Z. Stewart
- Department of Biochemistry & Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC3086, Australia
| | - Tatyana Mamonova
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA15261
| | - W. Bruce Sneddon
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA15261
| | - Airah Javorsky
- Department of Biochemistry & Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC3086, Australia
| | - Yanmei Yang
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA15261
| | - Bin Wang
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA15261
| | - Thomas D. Nolin
- Department of Pharmacy and Therapeutics, Center for Clinical Pharmaceutical Sciences, University of Pittsburgh Schools of Pharmacy and Medicine, Pittsburgh, PA15216
- Department of Medicine Schools of Pharmacy and Medicine Renal-Electrolyte Division, University of Pittsburgh, Pittsburgh, PA15216
| | - Patrick O. Humbert
- Department of Biochemistry & Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC3086, Australia
- Department of Biochemistry & Pharmacology, University of Melbourne, Melbourne, VIC3010, Australia
- Department of Clinical Pathology, University of Melbourne, Melbourne, VIC3010, Australia
| | - Peter A. Friedman
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA15261
| | - Marc Kvansakul
- Department of Biochemistry & Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC3086, Australia
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Portales-Castillo I, Dean T, Cheloha RW, Creemer BA, Vilardaga JP, Savransky S, Khatri A, Jüppner H, Gardella TJ. Altered Signaling and Desensitization Responses in PTH1R Mutants Associated with Eiken Syndrome. Commun Biol 2023; 6:599. [PMID: 37268817 PMCID: PMC10238420 DOI: 10.1038/s42003-023-04966-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 05/22/2023] [Indexed: 06/04/2023] Open
Abstract
The parathyroid hormone receptor type 1 (PTH1R) is a G protein-coupled receptor that plays key roles in regulating calcium homeostasis and skeletal development via binding the ligands, PTH and PTH-related protein (PTHrP), respectively. Eiken syndrome is a rare disease of delayed bone mineralization caused by homozygous PTH1R mutations. Of the three mutations identified so far, R485X, truncates the PTH1R C-terminal tail, while E35K and Y134S alter residues in the receptor's amino-terminal extracellular domain. Here, using a variety of cell-based assays, we show that R485X increases the receptor's basal rate of cAMP signaling and decreases its capacity to recruit β-arrestin2 upon ligand stimulation. The E35K and Y134S mutations each weaken the binding of PTHrP leading to impaired β-arrestin2 recruitment and desensitization of cAMP signaling response to PTHrP but not PTH. Our findings support a critical role for interaction with β-arrestin in the mechanism by which the PTH1R regulates bone formation.
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Affiliation(s)
- Ignacio Portales-Castillo
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Thier Research Building, 50 Blossom St, Boston, MA, 02114, USA
- Department of Medicine, Division of Nephrology, Massachusetts General Hospital, and Harvard Medical School, Thier Research Building, 50 Blossom St, Boston, MA, 02114, USA
- Department of Medicine, Division of Nephrology, Washington University in St. Louis, BJCIH Building, 425 South Euclid St, St. Louis, MO, 63110, USA
| | - Thomas Dean
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Thier Research Building, 50 Blossom St, Boston, MA, 02114, USA
| | - Ross W Cheloha
- Chemical Biology in Signaling Section, Laboratory of Bioorganic Chemistry, National Institutes of Diabetes and Digestive and Kidney Diseases, Building 8, 8 Center Drive, Bethesda, MD, 20891, USA
| | - Brendan A Creemer
- Chemical Biology in Signaling Section, Laboratory of Bioorganic Chemistry, National Institutes of Diabetes and Digestive and Kidney Diseases, Building 8, 8 Center Drive, Bethesda, MD, 20891, USA
| | - Jean-Pierre Vilardaga
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Thomas E. Starzl Biomedical Science Tower, 200 Lothrop St, Pittsburgh, PA, 15261, USA
| | - Sofya Savransky
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Thomas E. Starzl Biomedical Science Tower, 200 Lothrop St, Pittsburgh, PA, 15261, USA
| | - Ashok Khatri
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Thier Research Building, 50 Blossom St, Boston, MA, 02114, USA
| | - Harald Jüppner
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Thier Research Building, 50 Blossom St, Boston, MA, 02114, USA
- Pediatric Nephrology Unit, Massachusetts General Hospital, and Harvard Medical School, Thier Research Building, 50 Blossom St, Boston, MA, 02114, USA
| | - Thomas J Gardella
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Thier Research Building, 50 Blossom St, Boston, MA, 02114, USA.
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8
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Petzold F, Schönauer R, Werner A, Halbritter J. Clinical and Functional Assessment of Digenicity in Renal Phosphate Wasting. Nutrients 2023; 15:2081. [PMID: 37432176 DOI: 10.3390/nu15092081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/21/2023] [Accepted: 04/24/2023] [Indexed: 07/12/2023] Open
Abstract
Apart from increased fluid intake, patients with kidney stone disease (KSD) due to renal phosphate wasting require specific metaphylaxis. NaPi2a, NaPi2c, and NHERF1 regulate plasma phosphate concentration by reabsorbing phosphate in proximal kidney tubules and have been found altered in monogenic hypophosphatemia with a risk of KSD. In this study, we aimed at assessing the combined genetic alterations impacting NaPi2a, NaPi2c, and NHERF1. Therefore, we screened our hereditary KSD registry for cases of oligo- and digenicity, conducted reverse phenotyping, and undertook functional studies. As a result, we identified three patients from two families with digenic alterations in NaPi2a, NaPi2c, and NHERF1. In family 1, the index patient, who presented with severe renal calcifications and a bone mineralization disorder, carried digenic alterations affecting both NaPi transporter 2a and 2c. Functional analysis confirmed an additive genetic effect. In family 2, the index patient presented with kidney function decline, distinct musculature-related symptoms, and intracellular ATP depletion. Genetically, this individual was found to harbor variants in both NaPi2c and NHERF1 pointing towards genetic interaction. In summary, digenicity and gene dosage are likely to impact the severity of renal phosphate wasting and should be taken into account in terms of metaphylaxis through phosphate substitution.
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Affiliation(s)
- Friederike Petzold
- Division of Nephrology, University of Leipzig Medical Center, 04103 Leipzig, Germany
| | - Ria Schönauer
- Division of Nephrology, University of Leipzig Medical Center, 04103 Leipzig, Germany
- Department of Nephrology, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Andreas Werner
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Jan Halbritter
- Division of Nephrology, University of Leipzig Medical Center, 04103 Leipzig, Germany
- Department of Nephrology, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany
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9
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Kulebyakin K, Tyurin-Kuzmin P, Sozaeva L, Voloshin N, Nikolaev M, Chechekhin V, Vigovskiy M, Sysoeva V, Korchagina E, Naida D, Vorontsova M. Dynamic Balance between PTH1R-Dependent Signal Cascades Determines Its Pro- or Anti-Osteogenic Effects on MSC. Cells 2022; 11:3519. [PMID: 36359914 PMCID: PMC9656268 DOI: 10.3390/cells11213519] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/29/2022] [Accepted: 11/02/2022] [Indexed: 03/14/2024] Open
Abstract
Parathyroid hormone (PTH) is one of the key regulators of calcium and phosphate metabolism in the body, controlling bone metabolism and ion excretion by the kidneys. At present, attempts to use PTH as a therapeutic agent have been associated with side-effects, the nature of which is not always clear and predictable. In addition, it is known that in vivo impairment of PTH post-receptor signaling is associated with atypical differentiation behavior not only of bone cells, but also of connective tissues, including adipose tissue. In this work, we studied the functional responses of multipotent mesenchymal stromal cells (MSCs) to the action of PTH at the level of single cells. We used MSCs isolated from the periosteum and subcutaneous adipose tissue to compare characteristics of cell responses to PTH. We found that the hormone can activate three key responses via its receptor located on the surface of MSCs: single transients of calcium, calcium oscillations, and hormone-activated smooth increase in intracellular calcium. These types of calcium responses led to principally different cellular responses of MSCs. The cAMP-dependent smooth increase of intracellular calcium was associated with pro-osteogenic action of PTH, whereas phospholipase C dependent calcium oscillations led to a decrease in osteogenic differentiation intensity. Different variants of calcium responses are in dynamic equilibrium. Suppression of one type of response leads to increased activation of another type and, accordingly, to a change in the effect of PTH on cell differentiation.
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Affiliation(s)
- Konstantin Kulebyakin
- Faculty of Medicine, Lomonosov Moscow State University, 119991 Moscow, Russia
- Institute for Regenerative Medicine, Medical Research and Education Center, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Pyotr Tyurin-Kuzmin
- Faculty of Medicine, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Leila Sozaeva
- Endocrinology Research Center, 115478 Moscow, Russia
| | - Nikita Voloshin
- Faculty of Medicine, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Mikhail Nikolaev
- Faculty of Medicine, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Vadim Chechekhin
- Faculty of Medicine, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Maxim Vigovskiy
- Institute for Regenerative Medicine, Medical Research and Education Center, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Veronika Sysoeva
- Faculty of Medicine, Lomonosov Moscow State University, 119991 Moscow, Russia
| | | | - Daria Naida
- Burdenko Main Military Clinical Hospital, 105094 Moscow, Russia
| | - Maria Vorontsova
- Institute for Regenerative Medicine, Medical Research and Education Center, Lomonosov Moscow State University, 119234 Moscow, Russia
- Endocrinology Research Center, 115478 Moscow, Russia
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10
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Flores J, Takvorian PM, Weiss LM, Cali A, Gao N. Human microsporidian pathogen Encephalitozoon intestinalis impinges on enterocyte membrane trafficking and signaling. J Cell Sci 2021; 134:jcs.253757. [PMID: 33589497 DOI: 10.1242/jcs.253757] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 02/01/2021] [Indexed: 12/23/2022] Open
Abstract
Microsporidia are a large phylum of obligate intracellular parasites. Approximately a dozen species of microsporidia infect humans, where they are responsible for a variety of diseases and occasionally death, especially in immunocompromised individuals. To better understand the impact of microsporidia on human cells, we infected human colonic Caco2 cells with Encephalitozoon intestinalis, and showed that these enterocyte cultures can be used to recapitulate the life cycle of the parasite, including the spread of infection with infective spores. Using transmission electron microscopy, we describe this lifecycle and demonstrate nuclear, mitochondrial and microvillar alterations by this pathogen. We also analyzed the transcriptome of infected cells to reveal host cell signaling alterations upon infection. These high-resolution imaging and transcriptional profiling analysis shed light on the impact of the microsporidial infection on its primary human target cell type.This article has an associated First Person interview with the first authors of the paper.
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Affiliation(s)
- Juan Flores
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102, USA
| | - Peter M Takvorian
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102, USA.,Departments of Medicine and Pathology, Albert Einstein College of Medicine Bronx, New York 10461, USA
| | - Louis M Weiss
- Departments of Medicine and Pathology, Albert Einstein College of Medicine Bronx, New York 10461, USA
| | - Ann Cali
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102, USA
| | - Nan Gao
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102, USA
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11
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Mamonova T, Friedman PA. Noncanonical Sequences Involving NHERF1 Interaction with NPT2A Govern Hormone-Regulated Phosphate Transport: Binding Outside the Box. Int J Mol Sci 2021; 22:1087. [PMID: 33499384 PMCID: PMC7866199 DOI: 10.3390/ijms22031087] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/15/2021] [Accepted: 01/19/2021] [Indexed: 12/27/2022] Open
Abstract
Na+/H+ exchange factor-1 (NHERF1), a multidomain PDZ scaffolding phosphoprotein, is required for the type II sodium-dependent phosphate cotransporter (NPT2A)-mediated renal phosphate absorption. Both PDZ1 and PDZ2 domains are involved in NPT2A-dependent phosphate uptake. Though harboring identical core-binding motifs, PDZ1 and PDZ2 play entirely different roles in hormone-regulated phosphate transport. PDZ1 is required for the interaction with the C-terminal PDZ-binding sequence of NPT2A (-TRL). Remarkably, phosphocycling at Ser290 distant from PDZ1, the penultimate step for both parathyroid hormone (PTH) and fibroblast growth factor-23 (FGF23) regulation, controls the association between NHERF1 and NPT2A. PDZ2 interacts with the C-terminal PDZ-recognition motif (-TRL) of G Protein-coupled Receptor Kinase 6A (GRK6A), and that promotes phosphorylation of Ser290. The compelling biological puzzle is how PDZ1 and PDZ2 with identical GYGF core-binding motifs specifically recognize distinct binding partners. Binding determinants distinct from the canonical PDZ-ligand interactions and located "outside the box" explain PDZ domain specificity. Phosphorylation of NHERF1 by diverse kinases and associated conformational changes in NHERF1 add more complexity to PDZ-binding diversity.
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Affiliation(s)
- Tatyana Mamonova
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA;
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12
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van Gastel J, Leysen H, Boddaert J, Vangenechten L, Luttrell LM, Martin B, Maudsley S. Aging-related modifications to G protein-coupled receptor signaling diversity. Pharmacol Ther 2020; 223:107793. [PMID: 33316288 DOI: 10.1016/j.pharmthera.2020.107793] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/26/2020] [Indexed: 02/06/2023]
Abstract
Aging is a highly complex molecular process, affecting nearly all tissue systems in humans and is the highest risk factor in developing neurodegenerative disorders such as Alzheimer's and Parkinson's disease, cardiovascular disease and Type 2 diabetes mellitus. The intense complexity of the aging process creates an incentive to develop more specific drugs that attenuate or even reverse some of the features of premature aging. As our current pharmacopeia is dominated by therapeutics that target members of the G protein-coupled receptor (GPCR) superfamily it may be prudent to search for effective anti-aging therapeutics in this fertile domain. Since the first demonstration of GPCR-based β-arrestin signaling, it has become clear that an enhanced appreciation of GPCR signaling diversity may facilitate the creation of therapeutics with selective signaling activities. Such 'biased' ligand signaling profiles can be effectively investigated using both standard molecular biological techniques as well as high-dimensionality data analyses. Through a more nuanced appreciation of the quantitative nature across the multiple dimensions of signaling bias that drugs possess, researchers may be able to further refine the efficacy of GPCR modulators to impact the complex aberrations that constitute the aging process. Identifying novel effector profiles could expand the effective pharmacopeia and assist in the design of precision medicines. This review discusses potential non-G protein effectors, and specifically their potential therapeutic suitability in aging and age-related disorders.
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Affiliation(s)
- Jaana van Gastel
- Receptor Biology Lab, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium; Faculty of Pharmacy, Biomedical and Veterinary Science, University of Antwerp, Antwerp, Belgium
| | - Hanne Leysen
- Receptor Biology Lab, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium; Faculty of Pharmacy, Biomedical and Veterinary Science, University of Antwerp, Antwerp, Belgium
| | - Jan Boddaert
- Molecular Pathology Group, Faculty of Medicine and Health Sciences, Laboratory of Cell Biology and Histology, Antwerp, Belgium
| | - Laura Vangenechten
- Receptor Biology Lab, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Louis M Luttrell
- Division of Endocrinology, Diabetes & Medical Genetics, Medical University of South Carolina, USA
| | - Bronwen Martin
- Faculty of Pharmacy, Biomedical and Veterinary Science, University of Antwerp, Antwerp, Belgium
| | - Stuart Maudsley
- Receptor Biology Lab, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium; Faculty of Pharmacy, Biomedical and Veterinary Science, University of Antwerp, Antwerp, Belgium.
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13
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Dittmer KE, Heathcott RW, Marshall JC, Azarpeykan S. Expression of Phosphatonin-Related Genes in Sheep, Dog and Horse Kidneys Using Quantitative Reverse Transcriptase PCR. Animals (Basel) 2020; 10:ani10101806. [PMID: 33027890 PMCID: PMC7601102 DOI: 10.3390/ani10101806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 09/25/2020] [Accepted: 10/02/2020] [Indexed: 12/15/2022] Open
Abstract
Simple Summary Traditionally, it has been thought that control of body phosphorus was secondary to the tighter control of calcium. However, over the last 20 years, an extensive system for control of body phosphorus by proteins called phosphatonins has been shown to exist. Most research on phosphatonins has been done in rat or mouse models. This paper looks at whether important proteins and phosphorus channels in the phosphatonin pathways are present in the kidneys of dogs, horses and sheep. The results showed that all of the components of the phosphatonin system are present in these species, but that there are species differences in which protein or channel is most common, and in the relationships between the proteins and channels. This research is important because the phosphatonin system is involved in the progression of chronic kidney disease in humans and animals, and differences in the systems between animal species may affect treatment of chronic kidney disease. Abstract The aim of this preliminary study was to determine the relative expression of phosphatonin pathway-related genes in normal dog, sheep and horse kidneys and to explore the relationships between the different genes. Kidneys were collected post-mortem from 10 sheep, 10 horses and 8 dogs. RNA was extracted, followed by reverse transcriptase quantitative polymerase chain reaction for fibroblast growth factor receptor 1 IIIc (FGFR1IIIC), sodium-phosphate co-transporter (NPT) 1 (SLC17A1), NPT2a (SLC34A1), NPT2c (SLC34A3), parathyroid hormone 1 receptor (PTH1R), klotho (KL), vitamin D receptor (VDR), 1a-hydroxylase (CYP27B1) and 24-hydroxylase (CYP24A1). NPT2a was highly expressed in the dog kidneys, compared with those of the horses and sheep. NPT1 had greatest expression in horses and sheep, although the three different NPTs all had relatively similar expression in sheep. There was little variability in FGFR1IIIc expression, particularly in the dogs and horses. FGFR1IIIc expression was negatively correlated with NPT genes (except NPT2a in sheep), while NPT genes were all positively correlated with each other. Unexpectedly, klotho was positively correlated with NPT genes in all three species. These results provide the basis for further research into this important regulatory system. In particular, species differences in phosphatonin gene expression should be considered when considering the pathogenesis of chronic kidney disease.
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Affiliation(s)
- Keren E. Dittmer
- School of Veterinary Science, Massey University, Palmerston North 4410, New Zealand; (R.W.H.); (S.A.)
- Correspondence:
| | - Rosemary W. Heathcott
- School of Veterinary Science, Massey University, Palmerston North 4410, New Zealand; (R.W.H.); (S.A.)
| | - Jonathan C. Marshall
- School of Fundamental Sciences, Massey University, Palmerston North 4410, New Zealand;
| | - Sara Azarpeykan
- School of Veterinary Science, Massey University, Palmerston North 4410, New Zealand; (R.W.H.); (S.A.)
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14
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Physical Activity-Dependent Regulation of Parathyroid Hormone and Calcium-Phosphorous Metabolism. Int J Mol Sci 2020; 21:ijms21155388. [PMID: 32751307 PMCID: PMC7432834 DOI: 10.3390/ijms21155388] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/09/2020] [Accepted: 07/23/2020] [Indexed: 12/14/2022] Open
Abstract
Exercise perturbs homeostasis, alters the levels of circulating mediators and hormones, and increases the demand by skeletal muscles and other vital organs for energy substrates. Exercise also affects bone and mineral metabolism, particularly calcium and phosphate, both of which are essential for muscle contraction, neuromuscular signaling, biosynthesis of adenosine triphosphate (ATP), and other energy substrates. Parathyroid hormone (PTH) is involved in the regulation of calcium and phosphate homeostasis. Understanding the effects of exercise on PTH secretion is fundamental for appreciating how the body adapts to exercise. Altered PTH metabolism underlies hyperparathyroidism and hypoparathyroidism, the complications of which affect the organs involved in calcium and phosphorous metabolism (bone and kidney) and other body systems as well. Exercise affects PTH expression and secretion by altering the circulating levels of calcium and phosphate. In turn, PTH responds directly to exercise and exercise-induced myokines. Here, we review the main concepts of the regulation of PTH expression and secretion under physiological conditions, in acute and chronic exercise, and in relation to PTH-related disorders.
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15
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Abstract
Parathyroid hormone is an essential regulator of extracellular calcium and phosphate. PTH enhances calcium reabsorption while inhibiting phosphate reabsorption in the kidneys, increases the synthesis of 1,25-dihydroxyvitamin D, which then increases gastrointestinal absorption of calcium, and increases bone resorption to increase calcium and phosphate. Parathyroid disease can be an isolated endocrine disorder or part of a complex syndrome. Genetic mutations can account for diseases of parathyroid gland formulation, dysregulation of parathyroid hormone synthesis or secretion, and destruction of the parathyroid glands. Over the years, a number of different options are available for the treatment of different types of parathyroid disease. Therapeutic options include surgical removal of hypersecreting parathyroid tissue, administration of parathyroid hormone, vitamin D, activated vitamin D, calcium, phosphate binders, calcium-sensing receptor, and vitamin D receptor activators to name a few. The accurate assessment of parathyroid hormone also provides essential biochemical information to properly diagnose parathyroid disease. Currently available immunoassays may overestimate or underestimate bioactive parathyroid hormone because of interferences from truncated parathyroid hormone fragments, phosphorylation of parathyroid hormone, and oxidation of amino acids of parathyroid hormone.
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Affiliation(s)
- Edward Ki Yun Leung
- Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Los Angeles, CA, United States; Department of Pathology, Keck School of Medicine of University of Southern California, Los Angeles, CA, United States.
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16
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Abstract
Phosphate is an essential nutrient for life and is a critical component of bone formation, a major signaling molecule, and structural component of cell walls. Phosphate is also a component of high-energy compounds (i.e., AMP, ADP, and ATP) and essential for nucleic acid helical structure (i.e., RNA and DNA). Phosphate plays a central role in the process of mineralization, normal serum levels being associated with appropriate bone mineralization, while high and low serum levels are associated with soft tissue calcification. The serum concentration of phosphate and the total body content of phosphate are highly regulated, a process that is accomplished by the coordinated effort of two families of sodium-dependent transporter proteins. The three isoforms of the SLC34 family (SLC34A1-A3) show very restricted tissue expression and regulate intestinal absorption and renal excretion of phosphate. SLC34A2 also regulates the phosphate concentration in multiple lumen fluids including milk, saliva, pancreatic fluid, and surfactant. Both isoforms of the SLC20 family exhibit ubiquitous expression (with some variation as to which one or both are expressed), are regulated by ambient phosphate, and likely serve the phosphate needs of the individual cell. These proteins exhibit similarities to phosphate transporters in nonmammalian organisms. The proteins are nonredundant as mutations in each yield unique clinical presentations. Further research is essential to understand the function, regulation, and coordination of the various phosphate transporters, both the ones described in this review and the phosphate transporters involved in intracellular transport.
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Affiliation(s)
- Nati Hernando
- University of Zurich-Irchel, Institute of Physiology, Zurich, Switzerland; Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky; and Robley Rex VA Medical Center, Louisville, Kentucky
| | - Kenneth Gagnon
- University of Zurich-Irchel, Institute of Physiology, Zurich, Switzerland; Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky; and Robley Rex VA Medical Center, Louisville, Kentucky
| | - Eleanor Lederer
- University of Zurich-Irchel, Institute of Physiology, Zurich, Switzerland; Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky; and Robley Rex VA Medical Center, Louisville, Kentucky
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17
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Tanaka T, Takao-Kawabata R, Takakura A, Shimazu Y, Nakatsugawa M, Ito A, Lee JW, Kawasaki K, Iimura T. Teriparatide relieves ovariectomy-induced hyperalgesia in rats, suggesting the involvement of functional regulation in primary sensory neurons by PTH-mediated signaling. Sci Rep 2020; 10:5346. [PMID: 32210273 PMCID: PMC7093455 DOI: 10.1038/s41598-020-62045-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 03/03/2020] [Indexed: 11/09/2022] Open
Abstract
Clinical studies have reported that teriparatide (TPTD), a human parathyroid hormone analog, reduces back pain in osteoporotic patients. However, the mechanistic insights of this pharmacological action remain elusive. This study investigated the antinociceptive effect of TPTD mainly on primary sensory neurons in ovariectomized (OVX) rats. The plantar test showed thermal hyperalgesia in the OVX rats, which was significantly, but not fully, recovered immediately after the initial TPTD administration. The von Frey test also demonstrated reduced withdrawal threshold in the OVX rats. This was partially recovered by TPTD. Consistently, the number and size of spinal microglial cells were significantly increased in the OVX rats, while TPTD treatment significantly reduced the number but not size of these cells. RNA sequencing-based bioinformatics of the dorsal root ganglia (DRG) demonstrated that changes in neuro-protective and inflammatory genes were involved in the pharmacological effect of TPTD. Most neurons in the DRG expressed substantial levels of parathyroid hormone 1 receptor. TPTD treatment of the cultured DRG-derived neuronal cells reduced the cAMP level and augmented the intracellular calcium level as the concentration increased. These findings suggest that TPTD targets neuronal cells as well as bone cells to exert its pharmacological action.
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Affiliation(s)
- Tomoya Tanaka
- Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, 632-1 Mifuku, Izunokuni city, Shizuoka, 410-2321, Japan.,Department of Pharmacology, Graduate School of Dental Medicine, Hokkaido University, N13 W7, Sapporo, 060-8586, Japan
| | - Ryoko Takao-Kawabata
- Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, 632-1 Mifuku, Izunokuni city, Shizuoka, 410-2321, Japan.
| | - Aya Takakura
- Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, 632-1 Mifuku, Izunokuni city, Shizuoka, 410-2321, Japan.,Department of Pharmacology, Graduate School of Dental Medicine, Hokkaido University, N13 W7, Sapporo, 060-8586, Japan
| | - Yukari Shimazu
- Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, 632-1 Mifuku, Izunokuni city, Shizuoka, 410-2321, Japan
| | - Momoko Nakatsugawa
- Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, 632-1 Mifuku, Izunokuni city, Shizuoka, 410-2321, Japan
| | - Akitoshi Ito
- Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, 632-1 Mifuku, Izunokuni city, Shizuoka, 410-2321, Japan
| | - Ji-Won Lee
- Department of Pharmacology, Graduate School of Dental Medicine, Hokkaido University, N13 W7, Sapporo, 060-8586, Japan.,Division of Bio-Imaging, Proteo-Science Center (PROS), Ehime University, Shitsukawa, Toon city, Ehime, 791-0295, Japan
| | - Koh Kawasaki
- Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, 632-1 Mifuku, Izunokuni city, Shizuoka, 410-2321, Japan
| | - Tadahiro Iimura
- Department of Pharmacology, Graduate School of Dental Medicine, Hokkaido University, N13 W7, Sapporo, 060-8586, Japan. .,Division of Bio-Imaging, Proteo-Science Center (PROS), Ehime University, Shitsukawa, Toon city, Ehime, 791-0295, Japan.
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18
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Abstract
Over the past 25 years, successive cloning of SLC34A1, SLC34A2 and SLC34A3, which encode the sodium-dependent inorganic phosphate (Pi) cotransport proteins 2a-2c, has facilitated the identification of molecular mechanisms that underlie the regulation of renal and intestinal Pi transport. Pi and various hormones, including parathyroid hormone and phosphatonins, such as fibroblast growth factor 23, regulate the activity of these Pi transporters through transcriptional, translational and post-translational mechanisms involving interactions with PDZ domain-containing proteins, lipid microdomains and acute trafficking of the transporters via endocytosis and exocytosis. In humans and rodents, mutations in any of the three transporters lead to dysregulation of epithelial Pi transport with effects on serum Pi levels and can cause cardiovascular and musculoskeletal damage, illustrating the importance of these transporters in the maintenance of local and systemic Pi homeostasis. Functional and structural studies have provided insights into the mechanism by which these proteins transport Pi, whereas in vivo and ex vivo cell culture studies have identified several small molecules that can modify their transport function. These small molecules represent potential new drugs to help maintain Pi homeostasis in patients with chronic kidney disease - a condition that is associated with hyperphosphataemia and severe cardiovascular and skeletal consequences.
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19
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Abstract
Parathyroid hormone (PTH), PTH-related peptide (PTHrP), PTHR, and their cognate G protein-coupled receptor play defining roles in the regulation of extracellular calcium and phosphate metabolism and in controlling skeletal growth and repair. Acting through complex signaling mechanisms that in many instances proceed in a tissue-specific manner, precise control of these processes is achieved. A variety of direct and indirect disease processes, along with genetic anomalies, can cause these schemes to become dysfunctional. Here, we review the basic components of this regulatory network and present both the well-established elements and emerging findings and concepts with the overall objective to provide a framework for understanding the elementary aspects of how PTH and PTHrP behave and as a call to encourage further investigation that will yield more comprehensive understanding of the physiological and pathological steps at play, with a goal toward novel therapeutic interventions.
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20
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Fonin AV, Darling AL, Kuznetsova IM, Turoverov KK, Uversky VN. Multi-functionality of proteins involved in GPCR and G protein signaling: making sense of structure-function continuum with intrinsic disorder-based proteoforms. Cell Mol Life Sci 2019; 76:4461-4492. [PMID: 31428838 PMCID: PMC11105632 DOI: 10.1007/s00018-019-03276-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 08/05/2019] [Accepted: 08/12/2019] [Indexed: 12/21/2022]
Abstract
GPCR-G protein signaling system recognizes a multitude of extracellular ligands and triggers a variety of intracellular signaling cascades in response. In humans, this system includes more than 800 various GPCRs and a large set of heterotrimeric G proteins. Complexity of this system goes far beyond a multitude of pair-wise ligand-GPCR and GPCR-G protein interactions. In fact, one GPCR can recognize more than one extracellular signal and interact with more than one G protein. Furthermore, one ligand can activate more than one GPCR, and multiple GPCRs can couple to the same G protein. This defines an intricate multifunctionality of this important signaling system. Here, we show that the multifunctionality of GPCR-G protein system represents an illustrative example of the protein structure-function continuum, where structures of the involved proteins represent a complex mosaic of differently folded regions (foldons, non-foldons, unfoldons, semi-foldons, and inducible foldons). The functionality of resulting highly dynamic conformational ensembles is fine-tuned by various post-translational modifications and alternative splicing, and such ensembles can undergo dramatic changes at interaction with their specific partners. In other words, GPCRs and G proteins exist as sets of conformational/basic, inducible/modified, and functioning proteoforms characterized by a broad spectrum of structural features and possessing various functional potentials.
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Affiliation(s)
- Alexander V Fonin
- Laboratory of structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russian Federation
| | - April L Darling
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Irina M Kuznetsova
- Laboratory of structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russian Federation
| | - Konstantin K Turoverov
- Laboratory of structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russian Federation
- Department of Biophysics, Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya av. 29, St. Petersburg, 195251, Russian Federation
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
- Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow, Russian Federation.
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21
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Ardura JA, Portal-Núñez S, Alonso V, Bravo B, Gortazar AR. Handling Parathormone Receptor Type 1 in Skeletal Diseases: Realities and Expectations of Abaloparatide. Trends Endocrinol Metab 2019; 30:756-766. [PMID: 31409530 DOI: 10.1016/j.tem.2019.07.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 06/14/2019] [Accepted: 07/16/2019] [Indexed: 12/11/2022]
Abstract
Musculoskeletal disorders represent an elevated socioeconomic burden for developed aging societies. Osteoporosis (OP) has been treated with antiresorptive therapies or with teriparatide that was until recently the only anabolic therapy. However, approval of osteoporosis treatment in postmenopausal women with abaloparatide, which is an analog of parathyroid hormone-related peptide (PTHrP), has created a new alternative for OP management. The success of this new treatment is related to differential mechanisms of activation of PTH receptor type 1 (PTH1R) by abaloparatide and PTH. Here, we address the distinguishing mechanisms of PTH1R activation; the effects of PTH1R stimulation in osteoblast, osteocytes, and chondrocytes; the differences between PTH and abaloparatide actions on PTH1R; potential safety concerns; and future perspectives about abaloparatide use in other musculoskeletal disorders.
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Affiliation(s)
- Juan A Ardura
- Bone Physiopathology Laboratory, Applied Molecular Medicine Institute (IMMA), Universidad San Pablo-CEU, CEU Universities, Campus Monteprincipe, 28925 Alcorcón, Madrid, Spain; Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad San Pablo-CEU, CEU Universities, Campus Monteprincipe, 28925 Alcorcón, Madrid, Spain.
| | - Sergio Portal-Núñez
- Bone Physiopathology Laboratory, Applied Molecular Medicine Institute (IMMA), Universidad San Pablo-CEU, CEU Universities, Campus Monteprincipe, 28925 Alcorcón, Madrid, Spain; Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad San Pablo-CEU, CEU Universities, Campus Monteprincipe, 28925 Alcorcón, Madrid, Spain
| | - Verónica Alonso
- Bone Physiopathology Laboratory, Applied Molecular Medicine Institute (IMMA), Universidad San Pablo-CEU, CEU Universities, Campus Monteprincipe, 28925 Alcorcón, Madrid, Spain; Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad San Pablo-CEU, CEU Universities, Campus Monteprincipe, 28925 Alcorcón, Madrid, Spain
| | - Beatriz Bravo
- Bone Physiopathology Laboratory, Applied Molecular Medicine Institute (IMMA), Universidad San Pablo-CEU, CEU Universities, Campus Monteprincipe, 28925 Alcorcón, Madrid, Spain; Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad San Pablo-CEU, CEU Universities, Campus Monteprincipe, 28925 Alcorcón, Madrid, Spain
| | - Arancha R Gortazar
- Bone Physiopathology Laboratory, Applied Molecular Medicine Institute (IMMA), Universidad San Pablo-CEU, CEU Universities, Campus Monteprincipe, 28925 Alcorcón, Madrid, Spain; Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad San Pablo-CEU, CEU Universities, Campus Monteprincipe, 28925 Alcorcón, Madrid, Spain
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22
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Wagner CA, Rubio-Aliaga I, Hernando N. Renal phosphate handling and inherited disorders of phosphate reabsorption: an update. Pediatr Nephrol 2019; 34:549-559. [PMID: 29275531 DOI: 10.1007/s00467-017-3873-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 12/08/2017] [Accepted: 12/12/2017] [Indexed: 01/12/2023]
Abstract
Renal phosphate handling critically determines plasma phosphate and whole body phosphate levels. Filtered phosphate is mostly reabsorbed by Na+-dependent phosphate transporters located in the brush border membrane of the proximal tubule: NaPi-IIa (SLC34A1), NaPi-IIc (SLC34A3), and Pit-2 (SLC20A2). Here we review new evidence for the role and relevance of these transporters in inherited disorders of renal phosphate handling. The importance of NaPi-IIa and NaPi-IIc for renal phosphate reabsorption and mineral homeostasis has been highlighted by the identification of mutations in these transporters in a subset of patients with infantile idiopathic hypercalcemia and patients with hereditary hypophosphatemic rickets with hypercalciuria. Both diseases are characterized by disturbed calcium homeostasis secondary to elevated 1,25-(OH)2 vitamin D3 as a consequence of hypophosphatemia. In vitro analysis of mutated NaPi-IIa or NaPi-IIc transporters suggests defective trafficking underlying disease in most cases. Monoallelic pathogenic mutations in both SLC34A1 and SLC34A3 appear to be very frequent in the general population and have been associated with kidney stones. Consistent with these findings, results from genome-wide association studies indicate that variants in SLC34A1 are associated with a higher risk to develop kidney stones and chronic kidney disease, but underlying mechanisms have not been addressed to date.
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Affiliation(s)
- Carsten A Wagner
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland. .,National Center for Competence in Research (NCCR) Kidney.CH, Zurich, Switzerland.
| | - Isabel Rubio-Aliaga
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.,National Center for Competence in Research (NCCR) Kidney.CH, Zurich, Switzerland
| | - Nati Hernando
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.,National Center for Competence in Research (NCCR) Kidney.CH, Zurich, Switzerland
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24
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Oliveira B, Unwin R, Walsh SB. Inherited proximal tubular disorders and nephrolithiasis. Urolithiasis 2019; 47:35-42. [PMID: 30673801 DOI: 10.1007/s00240-018-01103-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 12/08/2018] [Indexed: 12/20/2022]
Abstract
The proximal tubule is responsible for reclaiming water, phosphates and amino acids from the tubular filtrate. There are genetic defects in both phosphate and amino acid transporters leading to nephrolithiasis. This review also explores genetic defects in regulators of phosphate and calcium transport in this nephron segment that lead to stone formation.
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Affiliation(s)
- Ben Oliveira
- Royal Free Hospital/Medical School, Centre for Nephrology, University College London, London, NW3 2PF, UK
| | - Robert Unwin
- Royal Free Hospital/Medical School, Centre for Nephrology, University College London, London, NW3 2PF, UK.,AstraZeneca IMED ECD CVRM R&D, Gothenburg, Sweden
| | - Stephen B Walsh
- Royal Free Hospital/Medical School, Centre for Nephrology, University College London, London, NW3 2PF, UK.
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25
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Visualizing the regulation of SLC34 proteins at the apical membrane. Pflugers Arch 2019; 471:533-542. [PMID: 30613865 DOI: 10.1007/s00424-018-02249-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 12/19/2018] [Accepted: 12/20/2018] [Indexed: 10/27/2022]
Abstract
The cloning of the renal NaPi-2a (SLC34A1) and NaPi-2c (SLC34A3) phosphate transporters has made it possible to characterize the molecular and biophysical regulation of renal proximal tubular reabsorption of inorganic phosphate (Pi). Dietary factors, such as Pi and K, and several hormones and phosphatonins, including parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23), and glucocorticoids, regulate the transporters through various transcriptional, translational, and post-translational mechanisms that involve acute trafficking via endocytosis or exocytosis, interactions with PDZ domain proteins, lipid microdomains, and diffusion and clustering in the apical brush border membrane. The visualization of these trafficking events by means of novel microscopy techniques that includes fluorescence lifetime imaging microscopy (FLIM), Förster resonance energy transfer (FRET), fluctuation correlation spectroscopy (FCS), and modulation tracking (MT), is the primary focus of this review.
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26
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Abstract
Parathyroid hormone (PTH) is the major secretory product of the parathyroid glands, and in hypocalcemic conditions, can enhance renal calcium reabsorption, increase active vitamin D production to increase intestinal calcium absorption, and mobilize calcium from bone by increasing turnover, mainly but not exclusively in cortical bone. PTH has therefore found clinical use as replacement therapy in hypoparathyroidism. PTH also may have a physiologic role in augmenting bone formation, particularly in trabecular and to some extent in cortical bone. This action has been applied to the clinic to provide anabolic therapy for osteoporosis.
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Affiliation(s)
- David Goltzman
- Department of Medicine and Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec H4A 3J1, Canada; Departments of Medicine and of Physiology, McGill University, 845 Sherbrooke St West, Montreal, Quebec H3A 0B9, Canada.
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27
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Abstract
Our understanding of the regulation of phosphate balance has benefited tremendously from the molecular identification and characterization of genetic defects leading to a number of rare inherited or acquired disorders affecting phosphate homeostasis. The identification of the key phosphate-regulating hormone, fibroblast growth factor 23 (FGF23), as well as other molecules that control its production, such as the glycosyltransferase GALNT3, the endopeptidase PHEX, and the matrix protein DMP1, and molecules that function as downstream effectors of FGF23 such as the longevity factor Klotho and the phosphate transporters NPT2a and NPT2c, has permitted us to understand the complex interplay that exists between the kidneys, bone, parathyroid, and gut. Such insights from genetic disorders have allowed not only the design of potent targeted treatment of FGF23-dependent hypophosphatemic conditions, but also provide clinically relevant observations related to the dysregulation of mineral ion homeostasis in health and disease.
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Affiliation(s)
- Marta Christov
- Division of Nephrology, Department of Medicine, New York Medical College, Valhalla, NY, USA
| | - Harald Jüppner
- Endocrine Unit and Pediatric Nephrology Unit, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA.
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28
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Hernando N. NaPi-IIa interacting partners and their (un)known functional roles. Pflugers Arch 2018; 471:67-82. [PMID: 30022249 DOI: 10.1007/s00424-018-2176-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 06/26/2018] [Indexed: 01/14/2023]
Abstract
The sorting and stabilization of proteins at specific subcellular domains depend upon the formation of networks build up by specific protein-protein interactions. In addition, protein networks also ensure the specificity of many regulatory processes by bringing together regulatory molecules with their targets. Whereas the success on the identification of protein-protein interactions is (up to a point) technology-driven, the assignment of functional roles to specific partners remains a major challenge. This review summarizes the work that led to the identification of partners of the Na+/phosphate cotransporter NaPi-IIa as well as the effects of the interactions in the expression and/or regulation of the cotransporter.
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Affiliation(s)
- Nati Hernando
- Institute of Physiology, University Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
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29
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Peterson YK, Luttrell LM. The Diverse Roles of Arrestin Scaffolds in G Protein-Coupled Receptor Signaling. Pharmacol Rev 2017. [PMID: 28626043 DOI: 10.1124/pr.116.013367] [Citation(s) in RCA: 289] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The visual/β-arrestins, a small family of proteins originally described for their role in the desensitization and intracellular trafficking of G protein-coupled receptors (GPCRs), have emerged as key regulators of multiple signaling pathways. Evolutionarily related to a larger group of regulatory scaffolds that share a common arrestin fold, the visual/β-arrestins acquired the capacity to detect and bind activated GPCRs on the plasma membrane, which enables them to control GPCR desensitization, internalization, and intracellular trafficking. By acting as scaffolds that bind key pathway intermediates, visual/β-arrestins both influence the tonic level of pathway activity in cells and, in some cases, serve as ligand-regulated scaffolds for GPCR-mediated signaling. Growing evidence supports the physiologic and pathophysiologic roles of arrestins and underscores their potential as therapeutic targets. Circumventing arrestin-dependent GPCR desensitization may alleviate the problem of tachyphylaxis to drugs that target GPCRs, and find application in the management of chronic pain, asthma, and psychiatric illness. As signaling scaffolds, arrestins are also central regulators of pathways controlling cell growth, migration, and survival, suggesting that manipulating their scaffolding functions may be beneficial in inflammatory diseases, fibrosis, and cancer. In this review we examine the structure-function relationships that enable arrestins to perform their diverse roles, addressing arrestin structure at the molecular level, the relationship between arrestin conformation and function, and sites of interaction between arrestins, GPCRs, and nonreceptor-binding partners. We conclude with a discussion of arrestins as therapeutic targets and the settings in which manipulating arrestin function might be of clinical benefit.
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Affiliation(s)
- Yuri K Peterson
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy (Y.K.P.), and Departments of Medicine and Biochemistry and Molecular Biology (L.M.L.), Medical University of South Carolina, Charleston, South Carolina; and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.)
| | - Louis M Luttrell
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy (Y.K.P.), and Departments of Medicine and Biochemistry and Molecular Biology (L.M.L.), Medical University of South Carolina, Charleston, South Carolina; and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.)
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30
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Abstract
The adhesion G protein-coupled receptors (aGPCRs) are an evolutionarily ancient family of receptors that play key roles in many different physiological processes. These receptors are notable for their exceptionally long ectodomains, which span several hundred to several thousand amino acids and contain various adhesion-related domains, as well as a GPCR autoproteolysis-inducing (GAIN) domain. The GAIN domain is conserved throughout almost the entire family and undergoes autoproteolysis to cleave the receptors into two noncovalently-associated protomers. Recent studies have revealed that the signaling activity of aGPCRs is largely determined by changes in the interactions among these protomers. We review recent advances in understanding aGPCR activation mechanisms and discuss the physiological roles and pharmacological properties of aGPCRs, with an eye toward the potential utility of these receptors as drug targets.
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Affiliation(s)
- Ryan H Purcell
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia, 30322, USA;
| | - Randy A Hall
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia, 30322, USA;
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31
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Yang Y, Lei H, Qiang YW, Wang B. Ixazomib enhances parathyroid hormone-induced β-catenin/T-cell factor signaling by dissociating β-catenin from the parathyroid hormone receptor. Mol Biol Cell 2017; 28:1792-1803. [PMID: 28495797 PMCID: PMC5491187 DOI: 10.1091/mbc.e17-02-0096] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 05/02/2017] [Accepted: 05/03/2017] [Indexed: 12/15/2022] Open
Abstract
The proteasome inhibitor ixazomib (Izb) dissociates β-catenin from the PTH receptor to enhance PTH stimulation of β-catenin/TCF signaling through the cAMP/PKA signaling pathway. These findings provide a rationale for the use of Izb as an adjunct in the treatment of osteoporosis with PTH. The anabolic action of PTH in bone is mostly mediated by cAMP/PKA and Wnt-independent activation of β-catenin/T-cell factor (TCF) signaling. β-Catenin switches the PTH receptor (PTHR) signaling from cAMP/PKA to PLC/PKC activation by binding to the PTHR. Ixazomib (Izb) was recently approved as the first orally administered proteasome inhibitor for the treatment of multiple myeloma; it acts in part by inhibition of pathological bone destruction. Proteasome inhibitors were reported to stabilize β-catenin by the ubiquitin-proteasome pathway. However, how Izb affects PTHR activation to regulate β-catenin/TCF signaling is poorly understood. In the present study, using CRISPR/Cas9 genome-editing technology, we show that Izb reverses β-catenin–mediated PTHR signaling switch and enhances PTH-induced cAMP generation and cAMP response element–luciferase activity in osteoblasts. Izb increases active forms of β-catenin and promotes β-catenin translocation, thereby dissociating β-catenin from the PTHR at the plasma membrane. Furthermore, Izb facilitates PTH-stimulated GSK3β phosphorylation and β-catenin phosphorylation. Thus Izb enhances PTH stimulation of β-catenin/TCF signaling via cAMP-dependent activation, and this effect is due to its separating β-catenin from the PTHR. These findings provide evidence that Izb may be used to improve the therapeutic efficacy of PTH for the treatment of osteoporosis and other resorptive bone diseases.
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Affiliation(s)
- Yanmei Yang
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107
| | - Hong Lei
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107.,College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Ya-Wei Qiang
- Myeloma Institute, University of Arkansas for Medical Sciences, Little Rock, AR 72205
| | - Bin Wang
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107
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32
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Luttrell LM, Maudsley S, Gesty-Palmer D. Translating in vitro ligand bias into in vivo efficacy. Cell Signal 2017; 41:46-55. [PMID: 28495495 DOI: 10.1016/j.cellsig.2017.05.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 05/04/2017] [Indexed: 01/04/2023]
Abstract
It is increasingly apparent that ligand structure influences both the efficiency with which G protein-coupled receptors (GPCRs) engage their downstream effectors and the manner in which they are activated. Thus, 'biased' agonists, synthetic ligands whose intrinsic efficacy differs from the native ligand, afford a strategy for manipulating GPCR signaling in ways that promote beneficial signals while blocking potentially deleterious ones. Still, there are significant challenges in relating in vitro ligand efficacy, which is typically measured in heterologous expression systems, to the biological response in vivo, where the ligand is acting on natively expressed receptors and in the presence of the endogenous ligand. This is particularly true of arrestin pathway-selective 'biased' agonists. The type 1 parathyroid hormone receptor (PTH1R) is a case in point. Parathyroid hormone (PTH) is the principal physiological regulator of calcium homeostasis, and PTH1R expressed on cells of the osteoblast lineage are an established therapeutic target in osteoporosis. In vitro, PTH1R signaling is highly sensitive to ligand structure, and PTH analogs that affect the selectivity/kinetics of G protein coupling or that engage arrestin-dependent signaling mechanisms without activating heterotrimeric G proteins have been identified. In vivo, intermittent administration of conventional PTH analogs accelerates the rate of osteoblastic bone formation, largely through known cAMP-dependent mechanisms. Paradoxically, both intermittent and continuous administration of an arrestin pathway-selective PTH analog, which in vivo would be expected to antagonize endogenous PTH1R-cAMP signaling, also increases bone mass. Transcriptomic analysis of tissue from treated animals suggests that conventional and arrestin pathway-selective PTH1R ligands act in largely different ways, with the latter principally affecting pathways involved in the regulation of cell cycle, survival, and migration/cytoskeletal dynamics. Such multi-dimensional in vitro and in vivo analyses of ligand bias may provide insights into the physiological roles of non-canonical arrestin-mediated signaling pathways in vivo, and provide a conceptual framework for translating arrestin pathway-selective ligands into viable therapeutics.
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Affiliation(s)
- Louis M Luttrell
- Division of Endocrinology, Diabetes & Medical Genetics, Medical University of South Carolina, Charleston, SC 29425, USA; Research Service of the Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, 29401, USA.
| | - Stuart Maudsley
- Translational Neurobiology Group, VIB Department of Molecular Genetics, Laboratory of Neurogenetics-Institute Born-Bunge, University of Antwerp, Belgium
| | - Diane Gesty-Palmer
- Division of Endocrinology, Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
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33
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Bastepe M, Turan S, He Q. Heterotrimeric G proteins in the control of parathyroid hormone actions. J Mol Endocrinol 2017; 58:R203-R224. [PMID: 28363951 PMCID: PMC5650080 DOI: 10.1530/jme-16-0221] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 02/17/2017] [Indexed: 12/17/2022]
Abstract
Parathyroid hormone (PTH) is a key regulator of skeletal physiology and calcium and phosphate homeostasis. It acts on bone and kidney to stimulate bone turnover, increase the circulating levels of 1,25 dihydroxyvitamin D and calcium and inhibit the reabsorption of phosphate from the glomerular filtrate. Dysregulated PTH actions contribute to or are the cause of several endocrine disorders. This calciotropic hormone exerts its actions via binding to the PTH/PTH-related peptide receptor (PTH1R), which couples to multiple heterotrimeric G proteins, including Gs and Gq/11 Genetic mutations affecting the activity or expression of the alpha-subunit of Gs, encoded by the GNAS complex locus, are responsible for several human diseases for which the clinical findings result, at least partly, from aberrant PTH signaling. Here, we review the bone and renal actions of PTH with respect to the different signaling pathways downstream of these G proteins, as well as the disorders caused by GNAS mutations.
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Affiliation(s)
- Murat Bastepe
- Endocrine UnitDepartment of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Serap Turan
- Department of Pediatric EndocrinologyMarmara University School of Medicine, Istanbul, Turkey
| | - Qing He
- Endocrine UnitDepartment of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
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34
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Mamonova T, Zhang Q, Chandra M, Collins BM, Sarfo E, Bu Z, Xiao K, Bisello A, Friedman PA. Origins of PDZ Binding Specificity. A Computational and Experimental Study Using NHERF1 and the Parathyroid Hormone Receptor. Biochemistry 2017; 56:2584-2593. [PMID: 28376304 DOI: 10.1021/acs.biochem.7b00078] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Na+/H+ exchanger regulatory factor-1 (NHERF1) is a scaffolding protein containing two PSD95/discs large protein/ZO1 (PDZ) domains that modifies the signaling, trafficking, and function of the parathyroid hormone receptor (PTHR), a family B G-protein-coupled receptor. PTHR and NHERF1 bind through a PDZ-ligand-recognition mechanism. We show that PTH elicits phosphorylation of Thr591 in the canonical -ETVM binding motif of PTHR. Conservative substitution of Thr591 with Cys does not affect PTH(1-34)-induced cAMP production or binding of PTHR to NHERF1. The findings suggested the presence of additional sites upstream of the PDZ-ligand motif through which the two proteins interact. Structural determinants outside the canonical NHERF1 PDZ-PTHR interface that influence binding have not been characterized. We used molecular dynamics (MD) simulation to predict residues involved in these interactions. Simulation data demonstrate that the negatively charged Glu side chains at positions -3, -5, and -6 upstream of the PDZ binding motif are involved in PDZ-PTHR recognition. Engineered mutant peptides representing the PTHR C-terminal region were used to measure the binding affinity with NHERF1 PDZ domains. Comparable micromolar affinities for peptides of different length were confirmed by fluorescence polarization, isothermal titration calorimetry, and surface plasmon resonance. Binding affinities measured for Ala variants validate MD simulations. The linear relation between the change in enthalpy and entropy following Ala substitutions at upstream positions -3, -5, and -6 of the PTHR peptide provides a clear example of the thermodynamic compensation rule. Overall, our data highlight sequences in PTHR that contribute to NHERF1 interaction and can be altered to prevent phosphorylation-mediated inhibition.
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Affiliation(s)
| | | | - Mintu Chandra
- Institute for Molecular Bioscience, The University of Queensland , St. Lucia, Brisbane, Queensland 4072, Australia
| | - Brett M Collins
- Institute for Molecular Bioscience, The University of Queensland , St. Lucia, Brisbane, Queensland 4072, Australia
| | - Edward Sarfo
- Department of Chemistry, City College of New York , New York, New York 10031, United States
| | - Zimei Bu
- Department of Chemistry, City College of New York , New York, New York 10031, United States
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35
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He L, Vanlandewijck M, Raschperger E, Andaloussi Mäe M, Jung B, Lebouvier T, Ando K, Hofmann J, Keller A, Betsholtz C. Analysis of the brain mural cell transcriptome. Sci Rep 2016; 6:35108. [PMID: 27725773 PMCID: PMC5057134 DOI: 10.1038/srep35108] [Citation(s) in RCA: 157] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 09/22/2016] [Indexed: 01/20/2023] Open
Abstract
Pericytes, the mural cells of blood microvessels, regulate microvascular development and function and have been implicated in many brain diseases. However, due to a paucity of defining markers, pericyte identification and functional characterization remain ambiguous and data interpretation problematic. In mice carrying two transgenic reporters, Pdgfrb-eGFP and NG2-DsRed, we found that double-positive cells were vascular mural cells, while the single reporters marked additional, but non-overlapping, neuroglial cells. Double-positive cells were isolated by fluorescence-activated cell sorting (FACS) and analyzed by RNA sequencing. To reveal defining patterns of mural cell transcripts, we compared the RNA sequencing data with data from four previously published studies. The meta-analysis provided a conservative catalogue of 260 brain mural cell-enriched gene transcripts. We validated pericyte-specific expression of two novel markers, vitronectin (Vtn) and interferon-induced transmembrane protein 1 (Ifitm1), using fluorescent in situ hybridization and immunohistochemistry. We further analyzed signaling pathways and interaction networks of the pericyte-enriched genes in silico. This work provides novel insight into the molecular composition of brain mural cells. The reported gene catalogue facilitates identification of brain pericytes by providing numerous new candidate marker genes and is a rich source for new hypotheses for future studies of brain mural cell physiology and pathophysiology.
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Affiliation(s)
- Liqun He
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Michael Vanlandewijck
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
- Integrated Cardio Metabolic Centre (ICMC), Karolinska Institute, Novum, SE-141 57 Huddinge, Stockholm, Sweden
| | - Elisabeth Raschperger
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
- Integrated Cardio Metabolic Centre (ICMC), Karolinska Institute, Novum, SE-141 57 Huddinge, Stockholm, Sweden
| | - Maarja Andaloussi Mäe
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Bongnam Jung
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Thibaud Lebouvier
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Koji Ando
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Jennifer Hofmann
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Annika Keller
- Division of Neurosurgery, Zürich University Hospital, Zürich University, Zürich, Switzerland
| | - Christer Betsholtz
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
- Integrated Cardio Metabolic Centre (ICMC), Karolinska Institute, Novum, SE-141 57 Huddinge, Stockholm, Sweden
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36
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Identification of key phosphorylation sites in PTH1R that determine arrestin3 binding and fine-tune receptor signaling. Biochem J 2016; 473:4173-4192. [PMID: 27623777 PMCID: PMC5103873 DOI: 10.1042/bcj20160740] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 09/07/2016] [Accepted: 09/12/2016] [Indexed: 11/17/2022]
Abstract
The parathyroid hormone receptor 1 (PTH1R) is a member of family B of G-protein-coupled receptors (GPCRs), predominantly expressed in bone and kidney where it modulates extracellular Ca2+ homeostasis and bone turnover. It is well established that phosphorylation of GPCRs constitutes a key event in regulating receptor function by promoting arrestin recruitment and coupling to G-protein-independent signaling pathways. Mapping phosphorylation sites on PTH1R would provide insights into how phosphorylation at specific sites regulates cell signaling responses and also open the possibility of developing therapeutic agents that could target specific receptor functions. Here, we have used mass spectrometry to identify nine sites of phosphorylation in the C-terminal tail of PTH1R. Mutational analysis revealed identified two clusters of serine and threonine residues (Ser489–Ser495 and Ser501–Thr506) specifically responsible for the majority of PTH(1–34)-induced receptor phosphorylation. Mutation of these residues to alanine did not affect negatively on the ability of the receptor to couple to G-proteins or activate extracellular-signal-regulated kinase 1/2. Using fluorescence resonance energy transfer and bioluminescence resonance energy transfer to monitor PTH(1–34)-induced interaction of PTH1R with arrestin3, we show that the first cluster Ser489–Ser495 and the second cluster Ser501–Thr506 operated in concert to mediate both the efficacy and potency of ligand-induced arrestin3 recruitment. We further demonstrate that Ser503 and Thr504 in the second cluster are responsible for 70% of arrestin3 recruitment and are key determinants for interaction of arrestin with the receptor. Our data are consistent with the hypothesis that the pattern of C-terminal tail phosphorylation on PTH1R may determine the signaling outcome following receptor activation.
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37
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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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38
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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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Chidiac P. RGS proteins destroy spare receptors: Effects of GPCR-interacting proteins and signal deamplification on measurements of GPCR agonist potency. Methods 2016; 92:87-93. [DOI: 10.1016/j.ymeth.2015.08.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 08/13/2015] [Accepted: 08/14/2015] [Indexed: 12/15/2022] Open
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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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Sauvanet C, Wayt J, Pelaseyed T, Bretscher A. Structure, Regulation, and Functional Diversity of Microvilli on the Apical Domain of Epithelial Cells. Annu Rev Cell Dev Biol 2015; 31:593-621. [DOI: 10.1146/annurev-cellbio-100814-125234] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Cécile Sauvanet
- Department of Molecular Biology and Genetics and Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, New York 14853;
| | - Jessica Wayt
- Department of Molecular Biology and Genetics and Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, New York 14853;
| | - Thaher Pelaseyed
- Department of Molecular Biology and Genetics and Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, New York 14853;
| | - Anthony Bretscher
- Department of Molecular Biology and Genetics and Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, New York 14853;
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Culhane KJ, Liu Y, Cai Y, Yan ECY. Transmembrane signal transduction by peptide hormones via family B G protein-coupled receptors. Front Pharmacol 2015; 6:264. [PMID: 26594176 PMCID: PMC4633518 DOI: 10.3389/fphar.2015.00264] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 10/23/2015] [Indexed: 01/28/2023] Open
Abstract
Although family B G protein-coupled receptors (GPCRs) contain only 15 members, they play key roles in transmembrane signal transduction of hormones. Family B GPCRs are drug targets for developing therapeutics for diseases ranging from metabolic to neurological disorders. Despite their importance, the molecular mechanism of activation of family B GPCRs remains largely unexplored due to the challenges in expression and purification of functional receptors to the quantity for biophysical characterization. Currently, there is no crystal structure available of a full-length family B GPCR. However, structures of key domains, including the extracellular ligand binding regions and seven-helical transmembrane regions, have been solved by X-ray crystallography and NMR, providing insights into the mechanisms of ligand recognition and selectivity, and helical arrangements within the cell membrane. Moreover, biophysical and biochemical methods have been used to explore functions, key residues for signaling, and the kinetics and dynamics of signaling processes. This review summarizes the current knowledge of the signal transduction mechanism of family B GPCRs at the molecular level and comments on the challenges and outlook for mechanistic studies of family B GPCRs.
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Affiliation(s)
- Kelly J Culhane
- Department of Molecular Biophysics and Biochemistry, Yale University New Haven, CT, USA
| | - Yuting Liu
- Department of Chemistry, Yale University New Haven, CT, USA
| | - Yingying Cai
- Department of Chemistry, Yale University New Haven, CT, USA
| | - Elsa C Y Yan
- Department of Chemistry, Yale University New Haven, CT, USA
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43
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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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Sauvanet C, Garbett D, Bretscher A. The function and dynamics of the apical scaffolding protein E3KARP are regulated by cell-cycle phosphorylation. Mol Biol Cell 2015; 26:3615-27. [PMID: 26310448 PMCID: PMC4603932 DOI: 10.1091/mbc.e15-07-0498] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 08/18/2015] [Indexed: 11/11/2022] Open
Abstract
We examine the dynamics and function of the apical scaffolding protein E3KARP/NHERF2, which consists of two PDZ domains and a tail containing an ezrin-binding domain. The exchange rate of E3KARP is greatly enhanced during mitosis due to phosphorylation at Ser-303 in its tail region. Whereas E3KARP can substitute for the function of the closely related scaffolding protein EBP50/NHERF1 in the formation of interphase microvilli, E3KARP S303D cannot. Moreover, the S303D mutation enhances the in vivo dynamics of the E3KARP tail alone, whereas in vitro the interaction of E3KARP with active ezrin is unaffected by S303D, implicating another factor regulating dynamics in vivo. A-Raf is found to be required for S303 phosphorylation in mitotic cells. Regulation of the dynamics of EBP50 is known to be dependent on its tail region but modulated by PDZ domain occupancy, which is not the case for E3KARP. Of interest, in both cases, the mechanisms regulating dynamics involve the tails, which are the most diverged region of the paralogues and probably evolved independently after a gene duplication event that occurred early in vertebrate evolution.
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Affiliation(s)
- Cécile Sauvanet
- Department of Molecular Biology and Genetics, Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, NY 14853
| | - Damien Garbett
- Department of Molecular Biology and Genetics, Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, NY 14853
| | - Anthony Bretscher
- Department of Molecular Biology and Genetics, Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, NY 14853
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45
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Maycas M, Ardura JA, de Castro LF, Bravo B, Gortázar AR, Esbrit P. Role of the Parathyroid Hormone Type 1 Receptor (PTH1R) as a Mechanosensor in Osteocyte Survival. J Bone Miner Res 2015; 30:1231-44. [PMID: 25529820 DOI: 10.1002/jbmr.2439] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 11/22/2014] [Accepted: 12/22/2014] [Indexed: 12/13/2022]
Abstract
Osteocytes have a major role in the control of bone remodeling. Mechanical stimulation decreases osteocyte apoptosis and promotes bone accrual, whereas skeletal unloading is deleterious in both respects. PTH1R ablation or overexpression in osteocytes in mice produces trabecular bone loss or increases bone mass, respectively. The latter effect was related to a decreased osteocyte apoptosis. Here, the putative role of PTH1R activation in osteocyte protection conferred by mechanical stimulation was assessed. Osteocytic MLO-Y4 cells were subjected to mechanical stimuli represented by hypotonic shock (216 mOsm/kg) or pulsatile fluid flow (8 Hz, 10 dynes/cm(2)) for a short pulse (10 min), with or without PTH1R antagonists or after transfection with specific PTHrP or PTH1R siRNA. These mechanical stimuli prevented cell death induced within 6 hours by etoposide (50 μM), related to PTHrP overexpression; and this effect was abolished by the calcium antagonist verapamil (1 μM), a phospholipase C (PLC) inhibitor (U73122; 10 μM), and a PKA activation inhibitor, Rp-cAMPS (25 μM), in these cells. Each mechanical stimulus also rapidly induced β-catenin stabilization and nuclear ERK translocation, which were inhibited by the PTH1R antagonist PTHrP(7-34) (1 μM), or PTH1R siRNA, and mimicked by PTHrP(1-36) (100 nM). Mechanical stretching by hypotonic shock did not affect cAMP production but rapidly (<1 min) stimulated Ca(i)(2+) transients in PTH1R-overexpressing HEK-293 cells and in MLO-Y4 cells, in which calcium signaling was unaffected by the presence of a PTHrP antiserum or PTHrP siRNA but inhibited by knocking down PTH1R. These novel findings indicate that PTH1R is an important component of mechanical signal transduction in osteocytic MLO-Y4 cells, and that PTH1R activation by PTHrP-independent and dependent mechanisms has a relevant role in the prosurvival action of mechanical stimulus in these cells.
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Affiliation(s)
- Marta Maycas
- Instituto de, Investigación Sanitaria (IIS)-, Fundación Jiménez Díaz, Universidad Autónoma de Madrid (UAM) and Red Temática de Investigación Cooperativa en Envejecimiento y Fragilidad (RETICEF), Madrid, Spain
| | - Juan A Ardura
- Instituto de, Investigación Sanitaria (IIS)-, Fundación Jiménez Díaz, Universidad Autónoma de Madrid (UAM) and Red Temática de Investigación Cooperativa en Envejecimiento y Fragilidad (RETICEF), Madrid, Spain
| | - Luis F de Castro
- Instituto de Medicina Molecular Aplicada (IMMA), Facultad de Medicina, Universidad San Pablo-CEU, Madrid, Spain
| | - Beatriz Bravo
- Instituto de Medicina Molecular Aplicada (IMMA), Facultad de Medicina, Universidad San Pablo-CEU, Madrid, Spain
| | - Arancha R Gortázar
- Instituto de Medicina Molecular Aplicada (IMMA), Facultad de Medicina, Universidad San Pablo-CEU, Madrid, Spain
| | - Pedro Esbrit
- Instituto de, Investigación Sanitaria (IIS)-, Fundación Jiménez Díaz, Universidad Autónoma de Madrid (UAM) and Red Temática de Investigación Cooperativa en Envejecimiento y Fragilidad (RETICEF), Madrid, Spain
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Luttrell LM, Maudsley S, Bohn LM. Fulfilling the Promise of "Biased" G Protein-Coupled Receptor Agonism. Mol Pharmacol 2015; 88:579-88. [PMID: 26134495 DOI: 10.1124/mol.115.099630] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 07/01/2015] [Indexed: 12/13/2022] Open
Abstract
The fact that over 30% of current pharmaceuticals target heptahelical G protein-coupled receptors (GPCRs) attests to their tractability as drug targets. Although GPCR drug development has traditionally focused on conventional agonists and antagonists, the growing appreciation that GPCRs mediate physiologically relevant effects via both G protein and non-G protein effectors has prompted the search for ligands that can "bias" downstream signaling in favor of one or the other process. Biased ligands are novel entities with distinct signaling profiles dictated by ligand structure, and the potential prospect of biased ligands as better drugs has been pleonastically proclaimed. Indeed, preclinical proof-of-concept studies have demonstrated that both G protein and arrestin pathway-selective ligands can promote beneficial effects in vivo while simultaneously antagonizing deleterious ones. But along with opportunity comes added complexity and new challenges for drug discovery. If ligands can be biased, then ligand classification becomes assay dependent, and more nuanced screening approaches are needed to capture ligand efficacy across several dimensions of signaling. Moreover, because the signaling repertoire of biased ligands differs from that of the native agonist, unpredicted responses may arise in vivo as these unbalanced signals propagate. For any given GPCR target, establishing a framework relating in vitro efficacy to in vivo biologic response is crucial to biased drug discovery. This review discusses approaches to describing ligand efficacy in vitro, translating ligand bias into biologic response, and developing a systems-level understanding of biased agonism in vivo, with the overall goal of overcoming current barriers to developing biased GPCR therapeutics.
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Affiliation(s)
- Louis M Luttrell
- Departments of Medicine and Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.); Translational Neurobiology Group, VIB Department of Molecular Genetics, Laboratory of Neurogenetics-Institute Born-Bunge, University of Antwerp, Belgium (S.M.); and Department of Molecular Therapeutics and Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida (L.M.B.)
| | - Stuart Maudsley
- Departments of Medicine and Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.); Translational Neurobiology Group, VIB Department of Molecular Genetics, Laboratory of Neurogenetics-Institute Born-Bunge, University of Antwerp, Belgium (S.M.); and Department of Molecular Therapeutics and Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida (L.M.B.)
| | - Laura M Bohn
- Departments of Medicine and Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.); Translational Neurobiology Group, VIB Department of Molecular Genetics, Laboratory of Neurogenetics-Institute Born-Bunge, University of Antwerp, Belgium (S.M.); and Department of Molecular Therapeutics and Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida (L.M.B.)
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Disruption of β-catenin binding to parathyroid hormone (PTH) receptor inhibits PTH-stimulated ERK1/2 activation. Biochem Biophys Res Commun 2015; 464:27-32. [PMID: 26047699 DOI: 10.1016/j.bbrc.2015.05.082] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 05/14/2015] [Indexed: 11/20/2022]
Abstract
The type I parathyroid hormone receptor (PTH1R) mediates PTH and PTH-related protein (PTHrP) actions on extracellular mineral ion homeostasis and bone remodeling. These effects depend in part on the activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2). Sequences located within or at the carboxyl-terminus of PTH1R control its activation and trafficking. β-catenin regulates PTH1R signaling and promotes chondrocyte hypertrophy through binding to the intracellular carboxyl-terminal region of the receptor. How the interaction of PTH1R with β-catenin affects PTH-stimulated ERK1/2 is unknown. In the present study, human embryonic kidney 293 (HEK293) cells, which do not express the PTH1R, were used to investigate whether the disruption of β-catenin binding to PTH1R affects PTH-stimulated ERK1/2 activation. We demonstrated that β-catenin interacted with wild-type PTH1R but this interaction was markedly reduced with mutant PTH1R (L584A/L585A). PTH stimulated less cAMP formation and increased more intracellular calcium in HEK293 cells transfected with wild-type PTH1R compared with mutant PTH1R, indicating β-catenin switches PTH1R signaling from Gαs activation to Gαq signaling. In addition, ERK1/2 activation in HEK293 cells transfected with PTH1R exhibited time and concentration dependence. PTH-stimulated ERK1/2 activation was mostly mediated through Gαq/PLC signaling pathway. Importantly, transfection of mutant PTH1R decreased PTH-induced ERK1/2 activation by inhibiting Gαq-mediated signaling. This study shows for the first time that the interference of β-catenin binding to PTH1R inhibits PTH-stimulated ERK1/2 phosphorylation.
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Walther C, Ferguson SSG. Minireview: Role of intracellular scaffolding proteins in the regulation of endocrine G protein-coupled receptor signaling. Mol Endocrinol 2015; 29:814-30. [PMID: 25942107 DOI: 10.1210/me.2015-1091] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The majority of hormones stimulates and mediates their signal transduction via G protein-coupled receptors (GPCRs). The signal is transmitted into the cell due to the association of the GPCRs with heterotrimeric G proteins, which in turn activates an extensive array of signaling pathways to regulate cell physiology. However, GPCRs also function as scaffolds for the recruitment of a variety of cytoplasmic protein-interacting proteins that bind to both the intracellular face and protein interaction motifs encoded by GPCRs. The structural scaffolding of these proteins allows GPCRs to recruit large functional complexes that serve to modulate both G protein-dependent and -independent cellular signaling pathways and modulate GPCR intracellular trafficking. This review focuses on GPCR interacting PSD95-disc large-zona occludens domain containing scaffolds in the regulation of endocrine receptor signaling as well as their potential role as therapeutic targets for the treatment of endocrinopathies.
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Affiliation(s)
- Cornelia Walther
- J. Allyn Taylor Centre for Cell Biology (C.W., S.S.G.F.), Robarts Research Institute, and Department of Physiology and Pharmacology (S.S.G.F.), University of Western Ontario, London, Ontario, Canada N6A 5K8
| | - Stephen S G Ferguson
- J. Allyn Taylor Centre for Cell Biology (C.W., S.S.G.F.), Robarts Research Institute, and Department of Physiology and Pharmacology (S.S.G.F.), University of Western Ontario, London, Ontario, Canada N6A 5K8
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49
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Dunn HA, Ferguson SSG. PDZ Protein Regulation of G Protein–Coupled Receptor Trafficking and Signaling Pathways. Mol Pharmacol 2015; 88:624-39. [DOI: 10.1124/mol.115.098509] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 03/25/2015] [Indexed: 01/03/2023] Open
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50
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Maudsley S, Martin B, Gesty-Palmer D, Cheung H, Johnson C, Patel S, Becker KG, Wood WH, Zhang Y, Lehrmann E, Luttrell LM. Delineation of a conserved arrestin-biased signaling repertoire in vivo. Mol Pharmacol 2015; 87:706-17. [PMID: 25637603 DOI: 10.1124/mol.114.095224] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Biased G protein-coupled receptor agonists engender a restricted repertoire of downstream events from their cognate receptors, permitting them to produce mixed agonist-antagonist effects in vivo. While this opens the possibility of novel therapeutics, it complicates rational drug design, since the in vivo response to a biased agonist cannot be reliably predicted from its in cellula efficacy. We have employed novel informatic approaches to characterize the in vivo transcriptomic signature of the arrestin pathway-selective parathyroid hormone analog [d-Trp(12), Tyr(34)]bovine PTH(7-34) in six different murine tissues after chronic drug exposure. We find that [d-Trp(12), Tyr(34)]bovine PTH(7-34) elicits a distinctive arrestin-signaling focused transcriptomic response that is more coherently regulated across tissues than that of the pluripotent agonist, human PTH(1-34). This arrestin-focused network is closely associated with transcriptional control of cell growth and development. Our demonstration of a conserved arrestin-dependent transcriptomic signature suggests a framework within which the in vivo outcomes of arrestin-biased signaling may be generalized.
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Affiliation(s)
- Stuart Maudsley
- National Institutes of Health, National Institute on Aging, Baltimore, Maryland (S.M., B.M., S.P., K.G.B., W.H.W., Y.Z., E.L.); Department of Medicine, Duke University Medical Center, Durham, North Carolina (D.G.-P.); National Institutes of Health, Center for Information Technology, Bethesda, Maryland (H.C., C.J.); Department of Medicine and Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.)
| | - Bronwen Martin
- National Institutes of Health, National Institute on Aging, Baltimore, Maryland (S.M., B.M., S.P., K.G.B., W.H.W., Y.Z., E.L.); Department of Medicine, Duke University Medical Center, Durham, North Carolina (D.G.-P.); National Institutes of Health, Center for Information Technology, Bethesda, Maryland (H.C., C.J.); Department of Medicine and Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.)
| | - Diane Gesty-Palmer
- National Institutes of Health, National Institute on Aging, Baltimore, Maryland (S.M., B.M., S.P., K.G.B., W.H.W., Y.Z., E.L.); Department of Medicine, Duke University Medical Center, Durham, North Carolina (D.G.-P.); National Institutes of Health, Center for Information Technology, Bethesda, Maryland (H.C., C.J.); Department of Medicine and Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.)
| | - Huey Cheung
- National Institutes of Health, National Institute on Aging, Baltimore, Maryland (S.M., B.M., S.P., K.G.B., W.H.W., Y.Z., E.L.); Department of Medicine, Duke University Medical Center, Durham, North Carolina (D.G.-P.); National Institutes of Health, Center for Information Technology, Bethesda, Maryland (H.C., C.J.); Department of Medicine and Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.)
| | - Calvin Johnson
- National Institutes of Health, National Institute on Aging, Baltimore, Maryland (S.M., B.M., S.P., K.G.B., W.H.W., Y.Z., E.L.); Department of Medicine, Duke University Medical Center, Durham, North Carolina (D.G.-P.); National Institutes of Health, Center for Information Technology, Bethesda, Maryland (H.C., C.J.); Department of Medicine and Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.)
| | - Shamit Patel
- National Institutes of Health, National Institute on Aging, Baltimore, Maryland (S.M., B.M., S.P., K.G.B., W.H.W., Y.Z., E.L.); Department of Medicine, Duke University Medical Center, Durham, North Carolina (D.G.-P.); National Institutes of Health, Center for Information Technology, Bethesda, Maryland (H.C., C.J.); Department of Medicine and Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.)
| | - Kevin G Becker
- National Institutes of Health, National Institute on Aging, Baltimore, Maryland (S.M., B.M., S.P., K.G.B., W.H.W., Y.Z., E.L.); Department of Medicine, Duke University Medical Center, Durham, North Carolina (D.G.-P.); National Institutes of Health, Center for Information Technology, Bethesda, Maryland (H.C., C.J.); Department of Medicine and Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.)
| | - William H Wood
- National Institutes of Health, National Institute on Aging, Baltimore, Maryland (S.M., B.M., S.P., K.G.B., W.H.W., Y.Z., E.L.); Department of Medicine, Duke University Medical Center, Durham, North Carolina (D.G.-P.); National Institutes of Health, Center for Information Technology, Bethesda, Maryland (H.C., C.J.); Department of Medicine and Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.)
| | - Yongqing Zhang
- National Institutes of Health, National Institute on Aging, Baltimore, Maryland (S.M., B.M., S.P., K.G.B., W.H.W., Y.Z., E.L.); Department of Medicine, Duke University Medical Center, Durham, North Carolina (D.G.-P.); National Institutes of Health, Center for Information Technology, Bethesda, Maryland (H.C., C.J.); Department of Medicine and Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.)
| | - Elin Lehrmann
- National Institutes of Health, National Institute on Aging, Baltimore, Maryland (S.M., B.M., S.P., K.G.B., W.H.W., Y.Z., E.L.); Department of Medicine, Duke University Medical Center, Durham, North Carolina (D.G.-P.); National Institutes of Health, Center for Information Technology, Bethesda, Maryland (H.C., C.J.); Department of Medicine and Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.)
| | - Louis M Luttrell
- National Institutes of Health, National Institute on Aging, Baltimore, Maryland (S.M., B.M., S.P., K.G.B., W.H.W., Y.Z., E.L.); Department of Medicine, Duke University Medical Center, Durham, North Carolina (D.G.-P.); National Institutes of Health, Center for Information Technology, Bethesda, Maryland (H.C., C.J.); Department of Medicine and Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.)
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