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Liu Y, Shao YT, Ward R, Ma L, Gui HX, Hao Q, Mu X, Yang Y, An S, Guo XX, Xu TR. The C-terminal of the α1b-adreneroceptor is a key determinant for its structure integrity and biological functions. Biosci Biotechnol Biochem 2021; 85:1128-1139. [PMID: 33693487 DOI: 10.1093/bbb/zbab034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 02/19/2021] [Indexed: 12/13/2022]
Abstract
The C-terminal of G protein-coupled receptors is now recognized as being important for G protein activation and signaling function. To detect the role of C-terminal tail in receptor activation, we used the α1b-AR, which has a long C-terminal of 164 amino acids. We constructed the intramolecular FRET sensors, in which the C-terminal was truncated to 10 (∆C-10), 20 (∆C-20), 30 (∆C-30), 50 (∆C-50), 70 (∆C-70), or 90 (∆C-90). The truncated mutants of ∆C-10, ∆C-20, or ∆C-30 cannot induce FRET signal changes and downstream ERK1/2 phosphorylation. However, the truncated mutants of ∆C-50, ∆C-70, or ∆C-90 induce significant FRET signal changes and downstream ERK1/2 phosphorylation, especially ∆C-90. This is particularly true in the case of the ∆C-90, ∆C-70, or ∆C-50 which retained the potential phosphorylation sites (Ser401, Ser404, Ser408, or Ser410). The ∆C-90 showed an increase in agonist-induced FRET signal changes and ERK1/2 phosphorylation in PKC- or endocytosis-dependent and EGFR-, src-, or β-arrestin2-independent.
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Affiliation(s)
- Ying Liu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, China.,Institute of Life Sciences, Jinzhou Medical University, Jinzhou, Liaoning, China
| | - Yu-Ting Shao
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, China
| | - Richard Ward
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Li Ma
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, China
| | - Hao-Xin Gui
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, China
| | - Qian Hao
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, China
| | - Xi Mu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, China
| | - Yang Yang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, China
| | - Su An
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, China
| | - Xiao-Xi Guo
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, China
| | - Tian-Rui Xu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, China
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Kotthoff M, Bauer J, Haag F, Krautwurst D. Conserved C-terminal motifs in odorant receptors instruct their cell surface expression and cAMP signaling. FASEB J 2021; 35:e21274. [PMID: 33464692 DOI: 10.1096/fj.202000182rr] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 10/30/2020] [Accepted: 11/30/2020] [Indexed: 11/11/2022]
Abstract
The highly individual plasma membrane expression and cAMP signaling of odorant receptors have hampered their ligand assignment and functional characterization in test cell systems. Chaperones have been identified to support the cell surface expression of only a portion of odorant receptors, with mechanisms remaining unclear. The presence of amino acid motifs that might be responsible for odorant receptors' individual intracellular retention or cell surface expression, and thus, for cAMP signaling, is under debate: so far, no such protein motifs have been suggested. Here, we demonstrate the existence of highly conserved C-terminal amino acid motifs, which discriminate at least between class-I and class-II odorant receptors, with their numbers of motifs increasing during evolution, by comparing C-terminal protein sequences from 4808 receptors across eight species. Truncation experiments and mutation analysis of C-terminal motifs, largely overlapping with helix 8, revealed single amino acids and their combinations to have differential impact on the cell surface expression and on stimulus-dependent cAMP signaling of odorant receptors in NxG 108CC15 cells. Our results demonstrate class-specific and individual C-terminal motif equipment of odorant receptors, which instruct their functional expression in a test cell system, and in situ may regulate their individual cell surface expression and intracellular cAMP signaling.
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Affiliation(s)
| | - Julia Bauer
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Franziska Haag
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Dietmar Krautwurst
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
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3
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Winfield I, Barkan K, Routledge S, Robertson NJ, Harris M, Jazayeri A, Simms J, Reynolds CA, Poyner DR, Ladds G. The Role of ICL1 and H8 in Class B1 GPCRs; Implications for Receptor Activation. Front Endocrinol (Lausanne) 2021; 12:792912. [PMID: 35095763 PMCID: PMC8796428 DOI: 10.3389/fendo.2021.792912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 12/15/2021] [Indexed: 11/13/2022] Open
Abstract
The first intracellular loop (ICL1) of G protein-coupled receptors (GPCRs) has received little attention, although there is evidence that, with the 8th helix (H8), it is involved in early conformational changes following receptor activation as well as contacting the G protein β subunit. In class B1 GPCRs, the distal part of ICL1 contains a conserved R12.48KLRCxR2.46b motif that extends into the base of the second transmembrane helix; this is weakly conserved as a [R/H]12.48KL[R/H] motif in class A GPCRs. In the current study, the role of ICL1 and H8 in signaling through cAMP, iCa2+ and ERK1/2 has been examined in two class B1 GPCRs, using mutagenesis and molecular dynamics. Mutations throughout ICL1 can either enhance or disrupt cAMP production by CGRP at the CGRP receptor. Alanine mutagenesis identified subtle differences with regard elevation of iCa2+, with the distal end of the loop being particularly sensitive. ERK1/2 activation displayed little sensitivity to ICL1 mutation. A broadly similar pattern was observed with the glucagon receptor, although there were differences in significance of individual residues. Extending the study revealed that at the CRF1 receptor, an insertion in ICL1 switched signaling bias between iCa2+ and cAMP. Molecular dynamics suggested that changes in ICL1 altered the conformation of ICL2 and the H8/TM7 junction (ICL4). For H8, alanine mutagenesis showed the importance of E3908.49b for all three signal transduction pathways, for the CGRP receptor, but mutations of other residues largely just altered ERK1/2 activation. Thus, ICL1 may modulate GPCR bias via interactions with ICL2, ICL4 and the Gβ subunit.
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MESH Headings
- Amino Acid Motifs/physiology
- Calcitonin Receptor-Like Protein/metabolism
- Calcitonin Receptor-Like Protein/physiology
- Calcitonin Receptor-Like Protein/ultrastructure
- Calcium Signaling
- Cyclic AMP/metabolism
- HEK293 Cells
- Humans
- MAP Kinase Signaling System
- Molecular Dynamics Simulation
- Protein Domains
- Protein Structure, Tertiary
- Receptor Activity-Modifying Protein 1/metabolism
- Receptor Activity-Modifying Protein 1/physiology
- Receptor Activity-Modifying Protein 1/ultrastructure
- Receptors, Calcitonin Gene-Related Peptide/metabolism
- Receptors, Calcitonin Gene-Related Peptide/physiology
- Receptors, Calcitonin Gene-Related Peptide/ultrastructure
- Receptors, Corticotropin-Releasing Hormone/metabolism
- Receptors, Corticotropin-Releasing Hormone/physiology
- Receptors, Corticotropin-Releasing Hormone/ultrastructure
- Receptors, G-Protein-Coupled
- Receptors, Glucagon/metabolism
- Receptors, Glucagon/physiology
- Receptors, Glucagon/ultrastructure
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Affiliation(s)
- Ian Winfield
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Kerry Barkan
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Sarah Routledge
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
- School of Life and Health Sciences, Aston University, Birmingham, United Kingdom
| | | | - Matthew Harris
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | | | - John Simms
- School of Life and Health Sciences, Aston University, Birmingham, United Kingdom
| | | | - David R. Poyner
- School of Life and Health Sciences, Aston University, Birmingham, United Kingdom
- *Correspondence: Graham Ladds, ; David R. Poyner,
| | - Graham Ladds
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
- *Correspondence: Graham Ladds, ; David R. Poyner,
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4
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Abstract
Sepsis, a life threating syndrome characterized by organ failure after infection, is the most common cause of death in hospitalized patients. The treatment of sepsis is generally supportive in nature, involving the administration of intravenous fluids, vasoactive substances and oxygen plus antibiotics to eliminate the pathogen. No drugs have been approved specifically for the treatment of sepsis, and clinical trials of potential therapies have failed to reduce mortality - suggesting that new approaches are needed. Abnormalities in the immune response elicited by the pathogen, ranging from excessive inflammation to immunosuppression, contribute to disease pathogenesis. Although hundreds of immunomodulatory agents are potentially available, it remains unclear which patient benefits from which immune therapy at a given time point. Results indicate the importance of personalized therapy, specifically the need to identify the type of intervention required by each individual patient at a given point in the disease process. To address this issue will require using biomarkers to stratify patients based on their individual immune status. This article reviews recent and ongoing clinical investigations using immunostimulatory or immunosuppressive therapies against sepsis including non-pharmacological and novel preclinical approaches.
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Abstract
The canonical CGRP receptor is a complex between calcitonin receptor-like receptor (CLR), a family B G-protein-coupled receptor (GPCR) and receptor activity-modifying protein 1 (RAMP1). A third protein, receptor component protein (RCP) is needed for coupling to Gs. CGRP can interact with other RAMP-receptor complexes, particularly the AMY1 receptor formed between the calcitonin receptor (CTR) and RAMP1. Crystal structures are available for the binding of CGRP27-37 [D31,P34,F35] to the extracellular domain (ECD) of CLR and RAMP1; these show that extreme C-terminal amide of CGRP interacts with W84 of RAMP1 but the rest of the analogue interacts with CLR. Comparison with the crystal structure of a fragment of the allied peptide adrenomedullin bound to the ECD of CLR/RAMP2 confirms the importance of the interaction of the ligand C-terminus and the RAMP in determining pharmacology specificity, although the RAMPs probably also have allosteric actions. A cryo-electron microscope structure of calcitonin bound to the full-length CTR associated with Gs gives important clues as to the structure of the complete receptor and suggests that the N-terminus of CGRP makes contact with His5.40b, high on TM5 of CLR. However, it is currently not known how the RAMPs interact with the TM bundle of any GPCR. Major challenges remain in understanding how the ECD and TM domains work together to determine ligand specificity, and how G-proteins influence this and the role of RCP. It seems likely that allosteric mechanisms are particularly important as are the dynamics of the receptors.
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Affiliation(s)
- John Simms
- School of Life and Health Science, Aston University, Birmingham, UK
- Coventry University, Coventry, UK
| | - Sarah Routledge
- School of Life and Health Science, Aston University, Birmingham, UK
| | - Romez Uddin
- School of Life and Health Science, Aston University, Birmingham, UK
| | - David Poyner
- School of Life and Health Science, Aston University, Birmingham, UK.
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6
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Structural basis for signal recognition and transduction by platelet-activating-factor receptor. Nat Struct Mol Biol 2018; 25:488-495. [PMID: 29808000 DOI: 10.1038/s41594-018-0068-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/20/2018] [Indexed: 12/19/2022]
Abstract
Platelet-activating-factor receptor (PAFR) responds to platelet-activating factor (PAF), a phospholipid mediator of cell-to-cell communication that exhibits diverse physiological effects. PAFR is considered an important drug target for treating asthma, inflammation and cardiovascular diseases. Here we report crystal structures of human PAFR in complex with the antagonist SR 27417 and the inverse agonist ABT-491 at 2.8-Å and 2.9-Å resolution, respectively. The structures, supported by molecular docking of PAF, provide insights into the signal-recognition mechanisms of PAFR. The PAFR-SR 27417 structure reveals an unusual conformation showing that the intracellular tips of helices II and IV shift outward by 13 Å and 4 Å, respectively, and helix VIII adopts an inward conformation. The PAFR structures, combined with single-molecule FRET and cell-based functional assays, suggest that the conformational change in the helical bundle is ligand dependent and plays a critical role in PAFR activation, thus greatly extending knowledge about signaling by G-protein-coupled receptors.
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Kuwasako K, Kitamura K, Nagata S, Sekiguchi T, Danfeng J, Murakami M, Hattori Y, Kato J. β-arrestins negatively control human adrenomedullin type 1-receptor internalization. Biochem Biophys Res Commun 2017; 487:438-443. [PMID: 28427767 DOI: 10.1016/j.bbrc.2017.04.083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 04/16/2017] [Indexed: 02/08/2023]
Abstract
Adrenomedullin (AM) is a potent hypotensive peptide that exerts a powerful variety of protective effects against multiorgan damage through the AM type 1 receptor (AM1 receptor), which consists of the calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 2 (RAMP2). Two β-arrestin (β-arr) isoforms, β-arr-1 and β-arr-2, play a central role in the agonist-induced internalization of many receptors for receptor resensitization. Notably, β-arr-biased agonists are now being tested in phase II clinical trials, targeting acute pain and acute heart failure. Here, we examined the effects of β-arr-1 and β-arr-2 on human AM1 receptor internalization. We constructed a V5-tagged chimera in which the cytoplasmic C-terminal tail (C-tail) of CLR was replaced with that of the β2-adrenergic receptor (β2-AR), and it was transiently transfected into HEK-293 cells that stably expressed RAMP2. The cell-surface expression and internalization of the wild-type or chimeric receptor were quantified by flow cytometric analysis. The [125I]AM binding and the AM-induced cAMP production of these receptors were also determined. Surprisingly, the coexpression of β-arr-1 or -2 resulted in significant decreases in AM1 receptor internalization without affecting AM binding and signaling prior to receptor internalization. Dominant-negative (DN) β-arr-1 or -2 also significantly decreased AM-induced AM1 receptor internalization. In contrast, the AM-induced internalization of the chimeric AM1 receptor was markedly augmented by the cotransfection of β-arr-1 or -2 and significantly reduced by the coexpression of DN-β-arr-1 or -2. These results were consistent with those seen for β2-AR. Thus, both β-arrs negatively control AM1 receptor internalization, which depends on the C-tail of CLR.
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Affiliation(s)
- Kenji Kuwasako
- Frontier Science Research Center, University of Miyazaki, Miyazaki 889-1692, Japan.
| | - Kazuo Kitamura
- Division of Circulation and Body Fluid Regulation, Faculty of Medicine, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Sayaka Nagata
- Division of Circulation and Body Fluid Regulation, Faculty of Medicine, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Toshio Sekiguchi
- Noto Marine Laboratory, Institute of Nature and Environmental Technology, Division of Marine Environmental Studies, Kanazawa University, Ishikawa 927-0553, Japan
| | - Jiang Danfeng
- Frontier Science Research Center, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Manabu Murakami
- Department of Pharmacology, Hirosaki University, Graduate School of Medicine, Hirosaki 036-8562, Japan
| | - Yuichi Hattori
- Department of Molecular and Medical Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan
| | - Johji Kato
- Frontier Science Research Center, University of Miyazaki, Miyazaki 889-1692, Japan
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8
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Schönauer R, Els-Heindl S, Beck-Sickinger AG. Adrenomedullin - new perspectives of a potent peptide hormone. J Pept Sci 2017; 23:472-485. [DOI: 10.1002/psc.2953] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 11/24/2016] [Accepted: 11/28/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Ria Schönauer
- Faculty of Biosciences, Pharmacy and Psychology, Institute of Biochemistry; Leipzig University; Brüderstraße 34 04103 Leipzig Germany
| | - Sylvia Els-Heindl
- Faculty of Biosciences, Pharmacy and Psychology, Institute of Biochemistry; Leipzig University; Brüderstraße 34 04103 Leipzig Germany
| | - Annette G. Beck-Sickinger
- Faculty of Biosciences, Pharmacy and Psychology, Institute of Biochemistry; Leipzig University; Brüderstraße 34 04103 Leipzig Germany
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9
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Sato T, Kawasaki T, Mine S, Matsumura H. Functional Role of the C-Terminal Amphipathic Helix 8 of Olfactory Receptors and Other G Protein-Coupled Receptors. Int J Mol Sci 2016; 17:ijms17111930. [PMID: 27869740 PMCID: PMC5133925 DOI: 10.3390/ijms17111930] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 11/09/2016] [Accepted: 11/14/2016] [Indexed: 11/23/2022] Open
Abstract
G protein-coupled receptors (GPCRs) transduce various extracellular signals, such as neurotransmitters, hormones, light, and odorous chemicals, into intracellular signals via G protein activation during neurological, cardiovascular, sensory and reproductive signaling. Common and unique features of interactions between GPCRs and specific G proteins are important for structure-based design of drugs in order to treat GPCR-related diseases. Atomic resolution structures of GPCR complexes with G proteins have revealed shared and extensive interactions between the conserved DRY motif and other residues in transmembrane domains 3 (TM3), 5 and 6, and the target G protein C-terminal region. However, the initial interactions formed between GPCRs and their specific G proteins remain unclear. Alanine scanning mutagenesis of the murine olfactory receptor S6 (mOR-S6) indicated that the N-terminal acidic residue of helix 8 of mOR-S6 is responsible for initial transient and specific interactions with chimeric Gα15_olf, resulting in a response that is 2.2-fold more rapid and 1.7-fold more robust than the interaction with Gα15. Our mutagenesis analysis indicates that the hydrophobic core buried between helix 8 and TM1–2 of mOR-S6 is important for the activation of both Gα15_olf and Gα15. This review focuses on the functional role of the C-terminal amphipathic helix 8 based on several recent GPCR studies.
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Affiliation(s)
- Takaaki Sato
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorioka, Ikeda, Osaka 563-8577, Japan.
| | - Takashi Kawasaki
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorioka, Ikeda, Osaka 563-8577, Japan.
| | - Shouhei Mine
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorioka, Ikeda, Osaka 563-8577, Japan.
| | - Hiroyoshi Matsumura
- College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
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10
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Lu M, Wu B. Structural studies of G protein-coupled receptors. IUBMB Life 2016; 68:894-903. [PMID: 27766738 DOI: 10.1002/iub.1578] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 10/08/2016] [Indexed: 11/08/2022]
Abstract
G protein-coupled receptors (GPCRs) comprise the largest membrane protein family. These receptors sense a variety of signaling molecules, activate multiple intracellular signal pathways, and act as the targets of over 40% of marketed drugs. Recent progress on GPCR structural studies provides invaluable insights into the structure-function relationship of the GPCR superfamily, deepening our understanding about the molecular mechanisms of GPCR signal transduction. Here, we review recent breakthroughs on GPCR structure determination and the structural features of GPCRs, and take the structures of chemokine receptor CCR5 and purinergic receptors P2Y1 R and P2Y12 R as examples to discuss the importance of GPCR structures on functional studies and drug discovery. In addition, we discuss the prospect of GPCR structure-based drug discovery. © 2016 IUBMB Life, 68(11):894-903, 2016.
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Affiliation(s)
- Mengjie Lu
- CAS Key laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Beili Wu
- CAS Key laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China. .,School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China.
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11
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Kuwasako K, Sekiguchi T, Nagata S, Jiang D, Hayashi H, Murakami M, Hattori Y, Kitamura K, Kato J. Inhibitory effects of two G protein-coupled receptor kinases on the cell surface expression and signaling of the human adrenomedullin receptor. Biochem Biophys Res Commun 2016; 470:894-9. [PMID: 26820533 DOI: 10.1016/j.bbrc.2016.01.138] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Accepted: 01/22/2016] [Indexed: 01/08/2023]
Abstract
Receptor activity-modifying protein 2 (RAMP2) enables the calcitonin receptor-like receptor (CLR, a family B GPCR) to form the type 1 adrenomedullin receptor (AM1 receptor). Here, we investigated the effects of the five non-visual GPCR kinases (GRKs 2 through 6) on the cell surface expression of the human (h)AM1 receptor by cotransfecting each of these GRKs into HEK-293 cells that stably expressed hRAMP2. Flow cytometric analysis revealed that when coexpressed with GRK4 or GRK5, the cell surface expression of the AM1 receptor was markedly decreased prior to stimulation with AM, thereby attenuating both the specific [(125)I]AM binding and AM-induced cAMP production. These inhibitory effects of both GRKs were abolished by the replacement of the cytoplasmic C-terminal tail (C-tail) of CLR with that of the calcitonin receptor (a family B GPCR) or β2-adrenergic receptor (a family A GPCR). Among the sequentially truncated CLR C-tail mutants, those lacking the five residues 449-453 (Ser-Phe-Ser-Asn-Ser) abolished the inhibition of the cell surface expression of CLR via the overexpression of GRK4 or GRK5. Thus, we provided new insight into the function of GRKs in agonist-unstimulated GPCR trafficking using a recombinant AM1 receptor and further determined the region of the CLR C-tail responsible for this GRK function.
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Affiliation(s)
- Kenji Kuwasako
- Frontier Science Research Center, University of Miyazaki, Miyazaki, 889-1692, Japan.
| | - Toshio Sekiguchi
- Noto Marine Laboratory, Division of Marine Environmental Studies, Institute of Nature and Environmental Technology, Kanazawa University, Ishikawa, 927-0553, Japan
| | - Sayaka Nagata
- Division of Circulatory and Body Fluid Regulation, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan
| | - Danfeng Jiang
- Frontier Science Research Center, University of Miyazaki, Miyazaki, 889-1692, Japan
| | - Hidetaka Hayashi
- Frontier Science Research Center, University of Miyazaki, Miyazaki, 889-1692, Japan
| | - Manabu Murakami
- Department of Pharmacology, Hirosaki University, Graduate School of Medicine, Hirosaki, 036-8562, Japan
| | - Yuichi Hattori
- Department of Molecular and Medical Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
| | - Kazuo Kitamura
- Division of Circulatory and Body Fluid Regulation, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan
| | - Johji Kato
- Frontier Science Research Center, University of Miyazaki, Miyazaki, 889-1692, Japan
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12
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Abstract
It is now recognized that G protein-coupled receptors (GPCRs), once considered largely independent functional units, have a far more diverse molecular architecture. Receptor activity-modifying proteins (RAMPs) provide an important example of proteins that interact with GPCRs to modify their function. RAMPs are able to act as pharmacological switches and chaperones, and they can regulate signaling and/or trafficking in a receptor-dependent manner. This review covers recent discoveries in the RAMP field and summarizes the known GPCR partners and functions of RAMPs. We also discuss the first peptide-bound structures of RAMP-GPCR complexes, which give insight into the molecular mechanisms that enable RAMPs to alter the pharmacology and signaling of GPCRs.
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Affiliation(s)
- Debbie L Hay
- School of Biological Sciences and Maurice Wilkins Center, University of Auckland, Auckland 1142, New Zealand;
| | - Augen A Pioszak
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104;
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13
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Abstract
The melanocortin-3 receptor (MC3R) is a member of the family A G protein-coupled receptors (GPCRs). The MC3R remains the most enigmatic of the melanocortin receptors with regard to its physiological functions, especially its role in energy homeostasis. The N/DPxxY motif and the eighth helix (helix 8) in the carboxyl terminus of GPCRs have been identified to be important for receptor expression, ligand binding, signal transduction and internalization. To gain a better understanding of the structure-function relationship of MC3R, we performed a systematic study of all 20 residues in this domain using alanine-scanning mutagenesis. We showed that although all mutants were expressed normally on the cell surface, eleven residues were important for ligand binding and one was indispensable for downstream cAMP generation. F347A showed constitutive activity in cAMP signaling while all the other mutants had normal basal activities. We studied the signaling capacity of nine mutants in the ERK1/2 signaling pathway. All of these mutants showed normal basal ERK1/2 phosphorylation levels. The pERK1/2 levels of six binding- or signaling-defective mutants were enhanced upon agonist stimulation. The unbalanced cAMP and pERK1/2 signaling pathways suggested the existence of biased signaling in MC3R mutants. In summary, we showed that the DPLIY motif and helix 8 was important for MC3R activation and signal transduction. Our data led to a better understanding of the structure-function relationship of MC3R.
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Affiliation(s)
- Zhao Yang
- Department of AnatomyPhysiology and Pharmacology, College of Veterinary Medicine, Auburn University, 212 Greene Hall, Auburn, Alabama 36849, USASchool of Applied Chemistry and Biological TechnologyShenzhen Polytechnic, Shenzhen 518055, China
| | - Zhi-Li Huang
- Department of AnatomyPhysiology and Pharmacology, College of Veterinary Medicine, Auburn University, 212 Greene Hall, Auburn, Alabama 36849, USASchool of Applied Chemistry and Biological TechnologyShenzhen Polytechnic, Shenzhen 518055, China Department of AnatomyPhysiology and Pharmacology, College of Veterinary Medicine, Auburn University, 212 Greene Hall, Auburn, Alabama 36849, USASchool of Applied Chemistry and Biological TechnologyShenzhen Polytechnic, Shenzhen 518055, China
| | - Ya-Xiong Tao
- Department of AnatomyPhysiology and Pharmacology, College of Veterinary Medicine, Auburn University, 212 Greene Hall, Auburn, Alabama 36849, USASchool of Applied Chemistry and Biological TechnologyShenzhen Polytechnic, Shenzhen 518055, China
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14
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Kawasaki T, Saka T, Mine S, Mizohata E, Inoue T, Matsumura H, Sato T. The N-terminal acidic residue of the cytosolic helix 8 of an odorant receptor is responsible for different response dynamics via G-protein. FEBS Lett 2015; 589:1136-42. [DOI: 10.1016/j.febslet.2015.03.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 03/23/2015] [Accepted: 03/23/2015] [Indexed: 10/23/2022]
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Underwood CR, Knudsen LB, Garibay PW, Peters GH, Reedtz-Runge S. Development of a cysteine-deprived and C-terminally truncated GLP-1 receptor. Peptides 2013; 49:100-8. [PMID: 24045233 DOI: 10.1016/j.peptides.2013.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 09/04/2013] [Accepted: 09/04/2013] [Indexed: 11/20/2022]
Abstract
The glucagon-like peptide-1 receptor (GLP-1R) belongs to family B of the G-protein coupled receptors (GPCRs), and has become a promising target for the treatment of type 2 diabetes. Here we describe the development and characterization of a fully functional cysteine-deprived and C-terminally truncated GLP-1R. Single cysteines were initially substituted with alanine, and functionally redundant cysteines were subsequently changed simultaneously. Our results indicate that Cys(174), Cys(226), Cys(296) and Cys(403) are important for the GLP-1-mediated response, whereas Cys(236), Cys(329), Cys(341), Cys(347), Cys(438), Cys(458) and Cys(462) are not. Extensive deletions were made in the C-terminal tail of GLP-1R in order to determine the limit for truncation. As for other family B GPCRs, we observed a direct correlation between the length of the C-terminal tail and specific binding of (125)I-GLP-1, indicating that the membrane proximal part of the C-terminal is involved in receptor expression at the cell surface. The results show that seven cysteines and more than half of the C-terminal tail can be removed from GLP-1R without compromising GLP-1 binding or function.
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Affiliation(s)
- Christina Rye Underwood
- Department of Incretin Biology, Novo Nordisk, DK-2820 Gentofte, Denmark; Department of Chemistry, MEMPHYS - Center for Biomembrane Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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16
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Barwell J, Gingell JJ, Watkins HA, Archbold JK, Poyner DR, Hay DL. Calcitonin and calcitonin receptor-like receptors: common themes with family B GPCRs? Br J Pharmacol 2012; 166:51-65. [PMID: 21649645 DOI: 10.1111/j.1476-5381.2011.01525.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The calcitonin receptor (CTR) and calcitonin receptor-like receptor (CLR) are two of the 15 human family B (or Secretin-like) GPCRs. CTR and CLR are of considerable biological interest as their pharmacology is moulded by interactions with receptor activity-modifying proteins. They also have therapeutic relevance for many conditions, such as osteoporosis, diabetes, obesity, lymphatic insufficiency, migraine and cardiovascular disease. In light of recent advances in understanding ligand docking and receptor activation in both the family as a whole and in CLR and CTR specifically, this review reflects how applicable general family B GPCR themes are to these two idiosyncratic receptors. We review the main functional domains of the receptors; the N-terminal extracellular domain, the juxtamembrane domain and ligand interface, the transmembrane domain and the intracellular C-terminal domain. Structural and functional findings from the CLR and CTR along with other family B GPCRs are critically appraised to gain insight into how these domains may function. The ability for CTR and CLR to interact with receptor activity-modifying proteins adds another level of sophistication to these receptor systems but means careful consideration is needed when trying to apply generic GPCR principles. This review encapsulates current thinking in the realm of family B GPCR research by highlighting both conflicting and recurring themes and how such findings relate to two unusual but important receptors, CTR and CLR.
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Affiliation(s)
- James Barwell
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
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17
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Kuwasako K, Hay DL, Nagata S, Hikosaka T, Kitamura K, Kato J. The third extracellular loop of the human calcitonin receptor-like receptor is crucial for the activation of adrenomedullin signalling. Br J Pharmacol 2012; 166:137-50. [PMID: 22142144 DOI: 10.1111/j.1476-5381.2011.01803.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND AND PURPOSE The extracellular loops (ECLs) in Family A GPCRs are important for ligand binding and receptor activation, but little is known about the function of Family B GPCR ECLs, especially ECL3. Calcitonin receptor-like receptor (CLR), a Family B GPCR, functions as a calcitonin gene-related peptide (CGRP) and an adrenomedullin (AM) receptor in association with three receptor activity-modifying proteins (RAMPs). Here, we examined the function of the ECL3 of human CLR within the CGRP and AM receptors. EXPERIMENTAL APPROACH A CLR ECL3 chimera, in which the ECL3 of CLR was substituted with that of VPAC2 (a Family B GPCR that is unable to interact with RAMPs), and CLR ECL3 point mutants were constructed and transiently transfected into HEK-293 cells along with each RAMP. Cell-surface expression of each receptor complex was then measured by flow cytometry; [(125) I]-CGRP and [(125) I]-AM binding and intracellular cAMP accumulation were also measured. KEY RESULTS Co-expression of the CLR ECL3 chimera with RAMP2 or RAMP3 led to significant reductions in the induction of cAMP signalling by AM, but CGRP signalling was barely affected, despite normal cell-surface expression of the receptors and normal [(125) I]-AM binding. The chimera had significantly decreased AM, but not CGRP, responses in the presence of RAMP1. Not all CLR ECL3 mutants supported these findings. CONCLUSIONS AND IMPLICATIONS The human CLR ECL3 is crucial for AM-induced cAMP responses via three CLR/RAMP heterodimers, and activation of these heterodimers probably relies on AM-induced conformational changes. This study provides a clue to the molecular basis of the activation of RAMP-based Family B GPCRs.
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Affiliation(s)
- Kenji Kuwasako
- Frontier Science Research Center, University of Miyazaki, Miyazaki, Japan.
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18
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Membrane-sensitive conformational states of helix 8 in the metabotropic Glu2 receptor, a class C GPCR. PLoS One 2012; 7:e42023. [PMID: 22870276 PMCID: PMC3411606 DOI: 10.1371/journal.pone.0042023] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 06/29/2012] [Indexed: 11/19/2022] Open
Abstract
The recent elucidation of the X-ray structure of several class A GPCRs clearly indicates that the amphipathic helix 8 (H8) is a conserved structural domain in most crystallized GPCRs. Very little is known about the presence and the possible role of an analogous H8 domain in the distantly related class C GPCRs. In this study, we investigated the structural properties for the H8 domain of the mGluR2 receptor, a class C GPCR, by applying extended molecular dynamics simulations. Our study indicates that the amphipathic H8 adopts membrane-sensitive conformational states, which depend on the membrane composition. Cholesterol-rich membranes stabilize the helical structure of H8 whereas cholesterol-depleted membranes induce a disruption of H8. The observed link between membrane cholesterol levels and H8 conformational states suggests that H8 behaves as a sensor of cholesterol concentration.
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19
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Kuwasako K, Kitamura K, Nagata S, Kato J. [Circulation control by adrenomedullin 1 receptor complex]. Nihon Yakurigaku Zasshi 2012; 140:8-13. [PMID: 22790226 DOI: 10.1254/fpj.140.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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20
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Aratake Y, Okuno T, Matsunobu T, Saeki K, Takayanagi R, Furuya S, Yokomizo T. Helix 8 of leukotriene B
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receptor 1 inhibits ligand‐induced internalization. FASEB J 2012; 26:4068-78. [DOI: 10.1096/fj.12-212050] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Yoshifusa Aratake
- Department of Medical BiochemistryGraduate School of Medical SciencesKyushu UniversityFukuokaJapan
- Department of Medicine and Bioregulatory ScienceGraduate School of Medical SciencesKyushu UniversityFukuokaJapan
| | - Toshiaki Okuno
- Department of Medical BiochemistryGraduate School of Medical SciencesKyushu UniversityFukuokaJapan
| | - Takehiko Matsunobu
- Department of Medical BiochemistryGraduate School of Medical SciencesKyushu UniversityFukuokaJapan
| | - Kazuko Saeki
- Department of Medical BiochemistryGraduate School of Medical SciencesKyushu UniversityFukuokaJapan
| | - Ryoichi Takayanagi
- Department of Medicine and Bioregulatory ScienceGraduate School of Medical SciencesKyushu UniversityFukuokaJapan
| | - Sonoko Furuya
- Section of Brain Structure Information, Supportive Center for Brain ResearchNational Institute for Physiological SciencesAichiJapan
| | - Takehiko Yokomizo
- Department of Medical BiochemistryGraduate School of Medical SciencesKyushu UniversityFukuokaJapan
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21
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Liao SB, Li HWR, Ho JC, Yeung WSB, Ng EHY, Cheung ANY, Tang F, O WS. Possible role of adrenomedullin in the pathogenesis of tubal ectopic pregnancy. J Clin Endocrinol Metab 2012; 97:2105-12. [PMID: 22456622 DOI: 10.1210/jc.2011-3290] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
CONTEXT Tubal ectopic pregnancy (tEP) is currently the leading cause of pregnancy-related deaths during the first trimester. Our current knowledge on the molecular pathogenesis is limited. OBJECTIVE The objective of the study was to find out the possible role of adrenomedullin (ADM) in the pathogenesis of tEP. DESIGN This was an experimental in vitro study on oviductal tissue. SETTING The study was conducted at a university teaching hospital. PATIENTS AND INTERVENTIONS Patients included those having oviducts removed surgically during salpingectomy for tEP or hysterectomy for benign gynecological conditions. Oviductal tissues were incubated in hormonal condition mimicking early pregnancy before used for in vitro experiments. MAIN OUTCOME MEASURES Plasma ADM concentration, oviductal expression of ADM and its receptors, ciliary beat frequency, smooth muscle contraction were measured. RESULTS The ciliary beat frequency and frequency of muscle contraction were lower in the oviducts from patients with tEP than those from simulated normal pregnancy. The plasma and oviductal tissue ADM levels were also lower. The decreases in ciliary beat and frequency of contraction were restored to normal after ADM treatment. CONCLUSIONS The results suggest that the lower ADM level in the oviducts of tEP may lead to the decrease in ciliary beating and muscle contraction, with the result that the embryo is retained and implanted in the oviduct. Our findings explain for the first time the etiology of tubal pregnancy on the basis of an impairment of the transport of the fertilized ovum resulting from an ADM deficiency and raise the possibility of using the plasma ADM level as a predictor for tubal ectopic pregnancy.
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Affiliation(s)
- S B Liao
- Department of Anatomy, The University of Hong Kong, First Floor, Laboratory Block, Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong
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22
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Egea SC, Dickerson IM. Direct interactions between calcitonin-like receptor (CLR) and CGRP-receptor component protein (RCP) regulate CGRP receptor signaling. Endocrinology 2012; 153:1850-60. [PMID: 22315449 PMCID: PMC3320266 DOI: 10.1210/en.2011-1459] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Calcitonin gene-related peptide (CGRP) is a neuropeptide with multiple neuroendocrine roles, including vasodilation, migraine, and pain. The receptor for CGRP is a G protein-coupled receptor (GPCR) that requires three proteins for function. CGRP binds to a heterodimer composed of the GPCR calcitonin-like receptor (CLR) and receptor activity-modifying protein (RAMP1), a single transmembrane protein required for pharmacological specificity and trafficking of the CLR/RAMP1 complex to the cell surface. In addition, the CLR/RAMP1 complex requires a third protein named CGRP-receptor component protein (RCP) for signaling. Previous studies have demonstrated that depletion of RCP from cells inhibits CLR signaling, and in vivo studies have demonstrated that expression of RCP correlates with CLR signaling and CGRP efficacy. It is not known whether RCP interacts directly with CLR to exert its effect. The current studies identified a direct interaction between RCP and an intracellular domain of CLR using yeast two-hybrid analysis and coimmunoprecipitation. When this interacting domain of CLR was expressed as a soluble fusion protein, it coimmunoprecipitated with RCP and inhibited signaling from endogenous CLR. Expression of this dominant-negative domain of CLR did not significantly inhibit trafficking of CLR to the cell surface, and thus RCP may not have a chaperone function for CLR. Instead, RCP may regulate CLR signaling in the cell membrane, and direct interaction between RCP and CLR is required for CLR activation. To date, RCP has been found to interact only with CLR and represents a novel neuroendocrine regulatory step in GPCR signaling.
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Affiliation(s)
- Sophie C Egea
- Department of Physiology and Biophysics, University of Miami School of Medicine, Miami, Florida 33101, USA
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23
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Kuwasako K, Kitamura K, Nagata S, Nozaki N, Kato J. Characterization of the single transmembrane domain of human receptor activity-modifying protein 3 in adrenomedullin receptor internalization. Biochem Biophys Res Commun 2012; 420:582-7. [PMID: 22445753 DOI: 10.1016/j.bbrc.2012.03.037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 03/08/2012] [Indexed: 01/27/2023]
Abstract
Two receptor activity-modifying proteins (RAMP2 and RAMP3) enable calcitonin receptor-like receptor (CLR) to function as two heterodimeric receptors (CLR/RAMP2 and CLR/RAMP3) for adrenomedullin (AM), a potent cardiovascular protective peptide. Following AM stimulation, both receptors undergo rapid internalization through a clathrin-dependent pathway, after which CLR/RAMP3, but not CLR/RAMP2, can be recycled to the cell surface for resensitization. However, human (h)RAMP3 mediates CLR internalization much less efficiently than does hRAMP2. Therefore, the molecular basis of the single transmembrane domain (TMD) and the intracellular domain of hRAMP3 during AM receptor internalization was investigated by transiently transfecting various RAMP chimeras and mutants into HEK-293 cells stably expressing hCLR. Flow cytometric analysis revealed that substituting the RAMP3 TMD with that of RAMP2 markedly enhanced AM-induced internalization of CLR. However, this replacement did not enhance the cell surface expression of CLR, [(125)I]AM binding affinity or AM-induced cAMP response. More detailed analyses showed that substituting the Thr(130)-Val(131) sequence in the RAMP3 TMD with the corresponding sequence (Ile(157)-Pro(158)) from RAMP2 significantly enhanced AM-mediated CLR internalization. In contrast, substituting the RAMP3 target sequence with Ala(130)-Ala(131) did not significantly affect CLR internalization. Thus, the RAMP3 TMD participates in the negative regulation of CLR/RAMP3 internalization, and the aforementioned introduction of the Ile-Pro sequence into the RAMP3 TMD may be a strategy for promoting receptor internalization/resensitization.
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Affiliation(s)
- Kenji Kuwasako
- Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, Miyazaki 889-1692, Japan.
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