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Voronina TA, Nesmelov AA, Kondratyeva SA, Deviatiiarov RM, Miyata Y, Tokumoto S, Cornette R, Gusev OA, Kikawada T, Shagimardanova EI. New group of transmembrane proteins associated with desiccation tolerance in the anhydrobiotic midge Polypedilum vanderplanki. Sci Rep 2020; 10:11633. [PMID: 32669703 PMCID: PMC7363813 DOI: 10.1038/s41598-020-68330-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 03/16/2020] [Indexed: 12/22/2022] Open
Abstract
Larvae of the sleeping chironomid Polypedilum vanderplanki are known for their extraordinary ability to survive complete desiccation in an ametabolic state called "anhydrobiosis". The unique feature of P. vanderplanki genome is the presence of expanded gene clusters associated with anhydrobiosis. While several such clusters represent orthologues of known genes, there is a distinct set of genes unique for P. vanderplanki. These include Lea-Island-Located (LIL) genes with no known orthologues except two of LEA genes of P. vanderplanki, PvLea1 and PvLea3. However, PvLIL proteins lack typical features of LEA such as the state of intrinsic disorder, hydrophilicity and characteristic LEA_4 motif. They possess four to five transmembrane domains each and we confirmed membrane targeting for three PvLILs. Conserved amino acids in PvLIL are located in transmembrane domains or nearby. PvLEA1 and PvLEA3 proteins are chimeras combining LEA-like parts and transmembrane domains, shared with PvLIL proteins. We have found that PvLil genes are highly upregulated during anhydrobiosis induction both in larvae of P. vanderplanki and P. vanderplanki-derived cultured cell line, Pv11. Thus, PvLil are a new intriguing group of genes that are likely to be associated with anhydrobiosis due to their common origin with some LEA genes and their induction during anhydrobiosis.
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Affiliation(s)
- Taisiya A Voronina
- Extreme Biology laboratory, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Alexander A Nesmelov
- Extreme Biology laboratory, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Sabina A Kondratyeva
- Extreme Biology laboratory, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Ruslan M Deviatiiarov
- Extreme Biology laboratory, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Yugo Miyata
- Division of Biotechnology, Institute of Agrobiological Sciences, National Institute of Agriculture and Food Research Organization (NARO), Tsukuba, Japan
| | - Shoko Tokumoto
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Richard Cornette
- Division of Biotechnology, Institute of Agrobiological Sciences, National Institute of Agriculture and Food Research Organization (NARO), Tsukuba, Japan
| | - Oleg A Gusev
- Extreme Biology laboratory, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
- KFU-RIKEN Translational Genomics Unit, RIKEN Cluster for Science, Technology and Innovation Hub, RIKEN, Yokohama, Japan
- Laboratory for Transcriptome Technology, RIKEN Center for Integrative Medical Sciences, RIKEN, Yokohama, Japan
| | - Takahiro Kikawada
- Division of Biotechnology, Institute of Agrobiological Sciences, National Institute of Agriculture and Food Research Organization (NARO), Tsukuba, Japan.
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan.
| | - Elena I Shagimardanova
- Extreme Biology laboratory, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia.
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Kumar P, Ashokan A, Aradhyam GK. Apelin binding to human APJ receptor leads to biased signaling. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:1748-1756. [DOI: 10.1016/j.bbapap.2016.09.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 08/26/2016] [Accepted: 09/22/2016] [Indexed: 12/15/2022]
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Gerbier R, Leroux V, Couvineau P, Alvear-Perez R, Maigret B, Llorens-Cortes C, Iturrioz X. New structural insights into the apelin receptor: identification of key residues for apelin binding. FASEB J 2014; 29:314-22. [PMID: 25359495 DOI: 10.1096/fj.14-256339] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Apelin is the endogenous ligand of the orphan 7-transmembrane domain GPCR APJ, now named the apelin receptor (ApelinR). Apelin plays a prominent role in body fluid and cardiovascular homeostasis. To better understand the structural organization of the ApelinR, we built 3 homology 3-dimensional (3D) models of the human ApelinR using the validated cholecystokinin receptor-1 3D model or the X-ray structures of the β2-adrenergic and CXCR4 receptors as templates. Docking of the pyroglutamyl form of apelin 13 (pE13F) into these models revealed the conservation at the bottom of the binding site of a hydrophobic cavity in which the C-terminal Phe of pE13F was embedded. In contrast, at the top of the binding site, depending on the model, different interactions were visualized between acidic residues of the ApelinR and the basic residues of pE13F. Using site-directed mutagenesis, we showed that Asp 92, Glu 172, and Asp 282 of rat ApelinR are key residues in apelin binding by interacting with Lys 8, Arg 2, and Arg 4 of pE13F, respectively. These residues are only seen in the CXCR4-based ApelinR 3D model, further validating this model. These findings bring new insights into the structural organization of the ApelinR and the mode of apelin binding.
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Affiliation(s)
- Romain Gerbier
- College de France, Laboratory of Central Neuropeptides in the Regulation of Body Fluid Homeostasis and Cardiovascular Functions, Center for Interdisciplinary Research in Biology (CIRB), Paris, France; CNRS, UMR 7241, Paris, France; and INSERM, U1050, Paris, France
| | - Vincent Leroux
- College de France, Laboratory of Central Neuropeptides in the Regulation of Body Fluid Homeostasis and Cardiovascular Functions, Center for Interdisciplinary Research in Biology (CIRB), Paris, France; CNRS, UMR 7241, Paris, France; and INSERM, U1050, Paris, France
| | - Pierre Couvineau
- College de France, Laboratory of Central Neuropeptides in the Regulation of Body Fluid Homeostasis and Cardiovascular Functions, Center for Interdisciplinary Research in Biology (CIRB), Paris, France; CNRS, UMR 7241, Paris, France; and INSERM, U1050, Paris, France
| | - Rodrigo Alvear-Perez
- College de France, Laboratory of Central Neuropeptides in the Regulation of Body Fluid Homeostasis and Cardiovascular Functions, Center for Interdisciplinary Research in Biology (CIRB), Paris, France; CNRS, UMR 7241, Paris, France; and INSERM, U1050, Paris, France
| | - Bernard Maigret
- College de France, Laboratory of Central Neuropeptides in the Regulation of Body Fluid Homeostasis and Cardiovascular Functions, Center for Interdisciplinary Research in Biology (CIRB), Paris, France; CNRS, UMR 7241, Paris, France; and INSERM, U1050, Paris, France
| | - Catherine Llorens-Cortes
- College de France, Laboratory of Central Neuropeptides in the Regulation of Body Fluid Homeostasis and Cardiovascular Functions, Center for Interdisciplinary Research in Biology (CIRB), Paris, France; CNRS, UMR 7241, Paris, France; and INSERM, U1050, Paris, France
| | - Xavier Iturrioz
- College de France, Laboratory of Central Neuropeptides in the Regulation of Body Fluid Homeostasis and Cardiovascular Functions, Center for Interdisciplinary Research in Biology (CIRB), Paris, France; CNRS, UMR 7241, Paris, France; and INSERM, U1050, Paris, France
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Matsoukas MT, Potamitis C, Plotas P, Androutsou ME, Agelis G, Matsoukas J, Zoumpoulakis P. Insights into AT1 receptor activation through AngII binding studies. J Chem Inf Model 2013; 53:2798-811. [PMID: 24053563 DOI: 10.1021/ci4003014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This study investigates the binding of angiotensin II (AngII) to the angiotensin II type 1 receptor (AT1R), taking into consideration several known activation elements that have been observed for G-protein-coupled receptors (GPCRs). In order to determine the crucial interactions of AngII upon binding, several MD simulations were implemented using AngII conformations derived from experimental data (NMR ROEs) and in silico flexible docking methodologies. An additional goal was to simulate the induced activation mechanism and examine the already known structural rearrangements of GPCRs upon activation. Performing MD simulations to the AT1R - AngII - lipids complex, a series of dynamic changes in the topology of AngII and the intracellular part of the receptor were observed. Overall, the present study proposes a complete binding profile of AngII to the AT1R, as well as the key transitional elements of the receptor and the agonist peptide upon activation through NMR and in silico studies.
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Affiliation(s)
- Minos-Timotheos Matsoukas
- Laboratori de Medicina Computacional, Unitat de Bioestadıstica, Facultat de Medicina, Universitat Autonoma de Barcelona , E-08193, Bellaterra, Barcelona, Spain
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Rodrigues ES, Martin RP, Silva RF, Nakaie CR, Oliveira L, Shimuta SI. Binding affinities and activation of Asp712Ala and Cys100Ser mutated kinin B1 receptor forms suggest a bimodal scheme for the molecule of bound-DABK. REGULATORY PEPTIDES 2013; 181:37-44. [PMID: 23318500 DOI: 10.1016/j.regpep.2012.12.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 11/30/2012] [Accepted: 12/17/2012] [Indexed: 06/01/2023]
Abstract
Mutant forms of kinin B(1) receptor (B(1)R) and analogs of the full agonist des-Arg(9)-bradykinin (DABK) were investigated aiming to verify the importance of selected receptor residues and of each agonist-peptide residue in the specific binding and activation. Linked by a specific disulfide bond (Cys(100)-Cys(650)), the N-terminal (N(t)) and the EC3 loop C-terminal (C(t)) segments of angiotensin II (AngII) receptor 1 (AT(1)R) have been identified to form an extracellular site for binding the agonist N(t) segment (Asp(1) and Arg(2) residues). Asp(712) residue at the receptor EC3 loop binds the peptide Arg(2) residue. By homology, a similar site might be considered for DABK binding to B(1)R since this receptor contains the same structural elements for composing the site in AT(1)R, namely the disulfide bond and the EC3 loop Asp(712) residue. DABK, Ala(n)-DABK analogs (n=Ala(1)-, Ala(2)-, Ala(3)-, Ala(4)-, Ala(5)-, Ala(6)-, Ala(7)-, Ala(8)-DABK), and other analogs were selected to binding wild-type, Asp712Ala and Cys100Ser mutated B(1)R receptors. The results obtained suggested that the same bimodal scheme adopted for AngII-AT(1)R system may be applied to DABK binding to B(1)R. The most crucial similarity in the two cases is that the N(t) segments of peptides equally bind to the homologous Asp(712) residue of both AT(1)R and B(1)R extracellular sites. Confirming this preliminary supposition, mutation of residues located at the B(1)R extracellular site as EC3 loop Asp(712) and Cys(100) caused the same modifications in biological assays observed in AT(1)R submitted to homologous mutations, such as significant weakening of agonist binding and reduction of post-receptor-activation processes. These findings provided enough support for defining a site that determines the specific binding of DABK to B(1)R receptors.
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Affiliation(s)
- E S Rodrigues
- Biophysics Department, Universidade Federal de São Paulo, Rua Botucatu, 862 7th floor, São Paulo, SP, Brazil
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Ragnarsson L, Wang CIA, Andersson Å, Fajarningsih D, Monks T, Brust A, Rosengren KJ, Lewis RJ. Conopeptide ρ-TIA defines a new allosteric site on the extracellular surface of the α1B-adrenoceptor. J Biol Chem 2012. [PMID: 23184947 DOI: 10.1074/jbc.m112.430785] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The G protein-coupled receptor (GPCR) superfamily is an important drug target that includes over 1000 membrane receptors that functionally couple extracellular stimuli to intracellular effectors. Despite the potential of extracellular surface (ECS) residues in GPCRs to interact with subtype-specific allosteric modulators, few ECS pharmacophores for class A receptors have been identified. Using the turkey β(1)-adrenergic receptor crystal structure, we modeled the α(1B)-adrenoceptor (α(1B)-AR) to help identify the allosteric site for ρ-conopeptide TIA, an inverse agonist at this receptor. Combining mutational radioligand binding and inositol 1-phosphate signaling studies, together with molecular docking simulations using a refined NMR structure of ρ-TIA, we identified 14 residues on the ECS of the α(1B)-AR that influenced ρ-TIA binding. Double mutant cycle analysis and docking confirmed that ρ-TIA binding was dominated by a salt bridge and cation-π between Arg-4-ρ-TIA and Asp-327 and Phe-330, respectively, and a T-stacking-π interaction between Trp-3-ρ-TIA and Phe-330. Water-bridging hydrogen bonds between Asn-2-ρ-TIA and Val-197, Trp-3-ρ-TIA and Ser-318, and the positively charged N terminus and Glu-186, were also identified. These interactions reveal that peptide binding to the ECS on transmembrane helix 6 (TMH6) and TMH7 at the base of extracellular loop 3 (ECL3) is sufficient to allosterically inhibit agonist signaling at a GPCR. The ligand-accessible ECS residues identified provide the first view of an allosteric inhibitor pharmacophore for α(1)-adrenoceptors and mechanistic insight and a new set of structural constraints for the design of allosteric antagonists at related GPCRs.
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Affiliation(s)
- Lotten Ragnarsson
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
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Short peptide constructs mimic agonist sites of AT(1)R and BK receptors. Amino Acids 2012; 44:835-46. [PMID: 23096780 DOI: 10.1007/s00726-012-1405-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 09/17/2012] [Indexed: 10/27/2022]
Abstract
Extracellular peptide ligand binding sites, which bind the N-termini of angiotensin II (AngII) and bradykinin (BK) peptides, are located on the N-terminal and extracellular loop 3 regions of the AT(1)R and BKRB(1) or BKRB(2) G-protein-coupled receptors (GPCRs). Here we synthesized peptides P15 and P13 corresponding to these receptor fragments and showed that only constructs in which these peptides were linked by S-S bond, and cyclized by closing the gap between them, could bind agonists. The formation of construct-agonist complexes was revealed by electron paramagnetic resonance spectra and fluorescence measurements of spin labeled biologically active analogs of AngII and BK (Toac(1)-AngII and Toac(0)-BK), where Toac is the amino acid-type paramagnetic and fluorescence quencher 2, 2, 6, 6-tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid. The inactive derivatives Toac(3)-AngII and Toac(3)-BK were used as controls. The interactions characterized by a significant immobilization of Toac and quenching of fluorescence in complexes between agonists and cyclic constructs were specific for each system of peptide-receptor construct assayed since no crossed reactions or reaction with inactive peptides could be detected. Similarities among AT, BKR, and chemokine receptors were identified, thus resulting in a configuration for AT(1)R and BKRB cyclic constructs based on the structure of the CXCR(4), an α-chemokine GPCR-type receptor.
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Wang CIA, Lewis RJ. Emerging opportunities for allosteric modulation of G-protein coupled receptors. Biochem Pharmacol 2012; 85:153-62. [PMID: 22975406 DOI: 10.1016/j.bcp.2012.09.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 09/03/2012] [Accepted: 09/04/2012] [Indexed: 12/23/2022]
Abstract
Their ubiquitous nature, wide cellular distribution and versatile molecular recognition and signalling help make G-protein binding receptors (GPCRs) the most important class of membrane proteins in clinical medicine, accounting for ∼40% of all current therapeutics. A large percentage of current drugs target the endogenous ligand binding (orthosteric) site, which are structurally and evolutionarily conserved, particularly among members of the same GPCR subfamily. With the recent advances in GPCR X-ray crystallography, new opportunities for developing novel subtype selective drugs have emerged. Given the increasing recognition that the extracellular surface conformation changes in response to ligand binding, it is likely that all GPCRs possess an allosteric site(s) capable of regulating GPCR signalling. Allosteric sites are less structurally conserved than their corresponding orthosteric site and thus provide new opportunities for the development of more selective drugs. Constitutive oligomerisation (dimerisation) identified in many of the GPCRs investigated, adds another dimension to the structural and functional complexity of GPCRs. In this review, we compare 60 crystal structures of nine GPCR subtypes (rhodopsin, ß₂-AR, ß₁-AR, A(2a)-AR, CXCR4, D₃R, H₁R, M₂R, M₃R) across four subfamilies of Class A GPCRs, and discuss mechanisms involved in receptor activation and potential allosteric binding sites across the highly variable extracellular surface of these GPCRs. This analysis has identified a new extracellular salt bridge (ESB-2) that might be exploited in the design of allosteric modulators.
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Affiliation(s)
- Ching-I Anderson Wang
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD 4072 Australia
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Wheatley M, Wootten D, Conner MT, Simms J, Kendrick R, Logan RT, Poyner DR, Barwell J. Lifting the lid on GPCRs: the role of extracellular loops. Br J Pharmacol 2012; 165:1688-1703. [PMID: 21864311 DOI: 10.1111/j.1476-5381.2011.01629.x] [Citation(s) in RCA: 224] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
GPCRs exhibit a common architecture of seven transmembrane helices (TMs) linked by intracellular loops and extracellular loops (ECLs). Given their peripheral location to the site of G-protein interaction, it might be assumed that ECL segments merely link the important TMs within the helical bundle of the receptor. However, compelling evidence has emerged in recent years revealing a critical role for ECLs in many fundamental aspects of GPCR function, which supported by recent GPCR crystal structures has provided mechanistic insights. This review will present current understanding of the key roles of ECLs in ligand binding, activation and regulation of both family A and family B GPCRs.
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Affiliation(s)
- M Wheatley
- School of Biosciences, University of Birmingham, Birmingham, UKDrug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, AustraliaDepartment of Pharmacology, Monash University, Parkville, Victoria, AustraliaSchool of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - D Wootten
- School of Biosciences, University of Birmingham, Birmingham, UKDrug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, AustraliaDepartment of Pharmacology, Monash University, Parkville, Victoria, AustraliaSchool of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - M T Conner
- School of Biosciences, University of Birmingham, Birmingham, UKDrug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, AustraliaDepartment of Pharmacology, Monash University, Parkville, Victoria, AustraliaSchool of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - J Simms
- School of Biosciences, University of Birmingham, Birmingham, UKDrug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, AustraliaDepartment of Pharmacology, Monash University, Parkville, Victoria, AustraliaSchool of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - R Kendrick
- School of Biosciences, University of Birmingham, Birmingham, UKDrug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, AustraliaDepartment of Pharmacology, Monash University, Parkville, Victoria, AustraliaSchool of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - R T Logan
- School of Biosciences, University of Birmingham, Birmingham, UKDrug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, AustraliaDepartment of Pharmacology, Monash University, Parkville, Victoria, AustraliaSchool of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - D R Poyner
- School of Biosciences, University of Birmingham, Birmingham, UKDrug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, AustraliaDepartment of Pharmacology, Monash University, Parkville, Victoria, AustraliaSchool of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - J Barwell
- School of Biosciences, University of Birmingham, Birmingham, UKDrug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, AustraliaDepartment of Pharmacology, Monash University, Parkville, Victoria, AustraliaSchool of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
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Chen MH, Sandberg DJ, Babu KR, Bubis J, Surya A, Ramos LS, Zapata HJ, Galan JF, Sandberg MN, Birge RR, Knox BE. Conserved residues in the extracellular loops of short-wavelength cone visual pigments. Biochemistry 2011; 50:6763-73. [PMID: 21688771 PMCID: PMC3518856 DOI: 10.1021/bi101557m] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The role of the extracellular loop region of a short-wavelength sensitive pigment, Xenopus violet cone opsin, is investigated via computational modeling, mutagenesis, and spectroscopy. The computational models predict a complex H-bonding network that stabilizes and connects the EC2-EC3 loop and the N-terminus. Mutations that are predicted to disrupt the H-bonding network are shown to produce visual pigments that do not stably bind chromophore and exhibit properties of a misfolded protein. The potential role of a disulfide bond between two conserved Cys residues, Cys(105) in TM3 and Cys(182) in EC2, is necessary for proper folding and trafficking in VCOP. Lastly, certain residues in the EC2 loop are predicted to stabilize the formation of two antiparallel β-strands joined by a hairpin turn, which interact with the chromophore via H-bonding or van der Waals interactions. Mutations of conserved residues result in a decrease in the level of chromophore binding. These results demonstrate that the extracellular loops are crucial for the formation of this cone visual pigment. Moreover, there are significant differences in the structure and function of this region in VCOP compared to that in rhodopsin.
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Affiliation(s)
- Min-Hsuan Chen
- Departments of Biochemistry & Molecular Biology and Ophthalmology, SUNY Upstate Medical University, Syracuse, NY 13210
| | - Daniel J. Sandberg
- Departments of Chemistry and of Molecular & Cell Biology, University of Connecticut, Storrs, CT 06269
| | - Kunnel R. Babu
- Departments of Biochemistry & Molecular Biology and Ophthalmology, SUNY Upstate Medical University, Syracuse, NY 13210
| | - Jose Bubis
- Departamento de Biologia Celular, Universidad Simon Bolivar, Caracas, Venezuela
| | - Arjun Surya
- Departments of Biochemistry & Molecular Biology and Ophthalmology, SUNY Upstate Medical University, Syracuse, NY 13210
| | - Lavoisier S. Ramos
- Departments of Chemistry and of Molecular & Cell Biology, University of Connecticut, Storrs, CT 06269
| | - Heidi J. Zapata
- Departments of Biochemistry & Molecular Biology and Ophthalmology, SUNY Upstate Medical University, Syracuse, NY 13210
| | - Jhenny F. Galan
- Departments of Chemistry and of Molecular & Cell Biology, University of Connecticut, Storrs, CT 06269
| | - Megan N. Sandberg
- Departments of Chemistry and of Molecular & Cell Biology, University of Connecticut, Storrs, CT 06269
| | - Robert R. Birge
- Departments of Chemistry and of Molecular & Cell Biology, University of Connecticut, Storrs, CT 06269
| | - Barry E. Knox
- Departments of Biochemistry & Molecular Biology and Ophthalmology, SUNY Upstate Medical University, Syracuse, NY 13210
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Martin RP, Rodrigues EDS, Correa SAA, Oliveira SM, Mortara RA, Oliveira L, Nakaie CR, Shimuta SI. Role of the second disulfide bridge (Cys(18)-Cys(274)) in stabilizing the inactive AT₁ receptor. Biol Chem 2010; 391:1189-95. [PMID: 20707602 DOI: 10.1515/bc.2010.117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Previous research showed that disruption of the Cys(18)-Cys(274) bond in the angiotensin II (AngII) AT₁ receptor mutant (C18S), expressed in CHO cells, causes an increase in the basal activity and attenuation of the maximum response to AngII. In addition, this mutant was mostly intracellularly distributed. Our aim was to investigate whether the intracellular presence of the mutant was due to a constitutive internalization or to a defective maturation of the receptor. The first hypothesis was assessed by pretreating the cells with losartan or [Sar¹Leu⁸]-AngII, specific AT₁ receptor antagonists, a maneuver to revert the receptor internalization. The second hypothesis was tested using calnexin, an endoplasmic reticulum marker. We found that treatment with AT₁ receptor antagonists causes an increase in the binding ability of the mutant to AngII. Furthermore, whereas the maximum effect is increased, it reduces the enhanced basal levels of IP₃. The hypothesis for a lack of maturation of the mutant receptor was ruled out because calnexin was poorly colocalized with the intracellular C18S receptor. Our results suggest that the mutation of the AT₁ receptor leads to a conformational structure similar to that of the active mode of the AT₁ receptor, favoring its internalization in the absence of the agonist.
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Affiliation(s)
- Renan Paulo Martin
- Department of Biophysics, Federal University of São Paulo, São Paulo 04023-062, Brazil
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Rana S, Baranski TJ. Third extracellular loop (EC3)-N terminus interaction is important for seven-transmembrane domain receptor function: implications for an activation microswitch region. J Biol Chem 2010; 285:31472-83. [PMID: 20663868 DOI: 10.1074/jbc.m110.129213] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The canonical heptahelical bundle architecture of seven-transmembrane domain (7TM) receptors is intertwined by three intra- and three extracellular loops, whose local conformations are important in receptor signaling. Many 7TM receptors contain a cysteine residue in the third extracellular loop (EC3) and a complementary cysteine residue on the N terminus. The functional role of such EC3-N terminus conserved cysteine pairs remains unclear. This study explores the role of the EC3-N terminus cysteine pairs on receptor conformation and G protein activation by disrupting them in the chemokine receptor CXCR4, while engineering a novel EC3-N terminus cysteine pair into the complement factor 5a receptor (C5aR), a chemo attractant receptor that lacks it. Mutated CXCR4 and C5aRs were expressed in engineered yeast. Mutation of the cysteine pair with the serine pair (C28S/C274S) in constitutively active mutant CXCR4 abrogated the receptor activation, whereas mutation with the aromatic pair (C28F-C274F) or the salt bridge pair (C28R/C274E), respectively, rescued or retained the receptor activation in response to CXCL12. In this context, the cysteine pair (Cys(30) and Cys(272)) engineered into the EC3-N terminus (Ser(30) and Ser(272)) of a novel constitutively active mutant of C5aR restrained the constitutive signaling without affecting the C5a-induced activation. Further mutational studies demonstrated a previously unappreciated role for Ser(272) on EC3 of C5aR and its interaction with the N terminus, thus defining a new microswitch region within the C5aR. Similar results were obtained with mutated CXCR4 and C5aRs expressed in COS-7 cells. These studies demonstrate a novel role of the EC3-N terminus cysteine pairs in G protein-coupled receptor activation and signaling.
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Affiliation(s)
- Soumendra Rana
- Division of Metabolism, Endocrinology, and Lipid Research, Department of Medicine, Washington University School of Medicine, St Louis, Missouri 63110, USA
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Barros AJ, Ito CM, Makino EN, Cembranelli FA, Moraes FC, Souza SE, Oliveira L, Shimuta SI, Nakaie CR. Factors regulating tachyphylaxis triggered by N-terminal-modified angiotensin II analogs. Biol Chem 2009; 390:1265-70. [DOI: 10.1515/bc.2009.143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractBinding of angiotensin II (DRVYIHPF, AngII) to its AT1receptor can trigger a process known as tachyphylaxis (loss of receptor response owing to repeated agonist stimulation). We propose a two-state binding model for tachyphylaxis where the N-terminal Asp1and Arg2residues of the peptide are supposed to initially bind to the N-terminal segment (Arg23) and to the EC-3 loop (Asp281) of an AT1molecule, respectively (state 1). Sequentially, a disruption of the salt bond between the AngII Asp1β-carboxyl function and the receptor Arg23can occur with release of the peptide N-terminal segment, favoring the binding of the Arg2residue to the EC-3 loop (Asp178,281, state 2). In the present study, we expanded this investigation by assaying pharmacological properties of different AngII analogs in guinea-pig ileum bearing modifications at positions 1 and 2. Most of these peptides were weak agonists but many of them had the ability to induce tachyphylaxis. These findings support the two-state model for tachyphylaxis, but alternative mechanisms were revealed where state 1 was no longer needed, depending on the chemical structure of AngII residue 1. Otherwise, any modification of the wild type AngII Arg2residue was deleterious for the tachyphylaxis mechanism.
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Martin RP, Rodrigues ES, Pacheco NAS, Corrêa SAA, Oliveira SM, Oliveira L, Nakaie CR, Shimuta SI. Distinct binding mode of 125I-AngII to AT1 receptor without the Cys18-Cys274 disulfide bridge. ACTA ACUST UNITED AC 2009; 158:14-8. [PMID: 19651161 DOI: 10.1016/j.regpep.2009.07.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 07/13/2009] [Accepted: 07/23/2009] [Indexed: 10/20/2022]
Abstract
Previous studies on angiotensin II (AngII) AT(1) receptor function have revealed that the N-terminal residues of AngII may modulate receptor activation by binding at the receptor extracellular site. A remarkable feature of this site is an insertion of 8 amino acids in the middle of the EC-3 loop including the Cys(274) residue that supposedly makes a disulfide bond with N-terminal Cys(18). As demonstrated by assays with Del(267-275)AT(1), the role of the Cys(18)-Cys(274) disulfide bridge is to keep a conformation of the inserted residues that allows a normal binding of the AngII N-terminal residues. C18S AT(1) receptor mutant, supposedly having a dissociated disulfide bridge, but an intact residue insertion, is constitutively activated and can less efficiently bind AngII. Similar results were observed when the S-S disulfide bond was disrupted in (C18S,C274S) AT(1) receptor. The importance of the free N-terminal amino group of Asp(1) and of the Arg(2) guanidino group for the binding of AngII to C18S mutant with EC-3 loop insertion was investigated by means of assays using AngII peptide analogues bearing a single mutation of Asp(1) for Sar(1) or Arg(2) for Lys(2), as ligands. This study showed that like AngII, [Sar(1)]-AngII can bind the C18S mutant receptor with low affinity whereas [Lys(2)]-AngII binding is still more reduced. Interestingly, when (125)I-AngII instead of (3)H-AngII was used, no significant binding of this mutant was observed although wild type AT(1) receptor was shown to bind all AngII analogues.
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Affiliation(s)
- Renan P Martin
- Department of Biophysics, Federal University of São Paulo, 04023-062 São Paulo, SP, Brazil
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Petrel C, Clauser E. Angiotensin II AT1 receptor constitutive activation: from molecular mechanisms to pathophysiology. Mol Cell Endocrinol 2009; 302:176-84. [PMID: 19061936 DOI: 10.1016/j.mce.2008.10.049] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Revised: 10/21/2008] [Accepted: 10/24/2008] [Indexed: 11/19/2022]
Abstract
Mutations activating the angiotensin II AT(1) receptor are important to identify and characterize because they give access to the activation mechanisms of this G protein coupled receptor and help to characterize the signaling pathways and the potential pathophysiology of this receptor. The different constitutively activated mutations of the AT(1) receptor are mostly localized in transmembrane domains (TM) and their characterization demonstrated that release of intramolecular constraints and movements among these TM are a necessary step for receptor activation. These mutations constitutively activate Gq linked signaling pathways, receptor internalization and maybe the G protein-independent signaling pathways. Expression of such mutations in mice is linked to hypertension and cardiovascular diseases, but such natural mutations have not been identified in human pathology.
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Affiliation(s)
- Christophe Petrel
- Institut Cochin, INSERM U567, University Paris Descartes, CNRS UMR8104, Paris, France
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Oliveira L, Costa-Neto CM, Nakaie CR, Schreier S, Shimuta SI, Paiva ACM. The Angiotensin II AT1 Receptor Structure-Activity Correlations in the Light of Rhodopsin Structure. Physiol Rev 2007; 87:565-92. [PMID: 17429042 DOI: 10.1152/physrev.00040.2005] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The most prevalent physiological effects of ANG II, the main product of the renin-angiotensin system, are mediated by the AT1 receptor, a rhodopsin-like AGPCR. Numerous studies of the cardiovascular effects of synthetic peptide analogs allowed a detailed mapping of ANG II's structural requirements for receptor binding and activation, which were complemented by site-directed mutagenesis studies on the AT1 receptor to investigate the role of its structure in ligand binding, signal transduction, phosphorylation, binding to arrestins, internalization, desensitization, tachyphylaxis, and other properties. The knowledge of the high-resolution structure of rhodopsin allowed homology modeling of the AT1 receptor. The models thus built and mutagenesis data indicate that physiological (agonist binding) or constitutive (mutated receptor) activation may involve different degrees of expansion of the receptor's central cavity. Residues in ANG II structure seem to control these conformational changes and to dictate the type of cytosolic event elicited during the activation. 1) Agonist aromatic residues (Phe8 and Tyr4) favor the coupling to G protein, and 2) absence of these residues can favor a mechanism leading directly to receptor internalization via phosphorylation by specific kinases of the receptor's COOH-terminal Ser and Thr residues, arrestin binding, and clathrin-dependent coated-pit vesicles. On the other hand, the NH2-terminal residues of the agonists ANG II and [Sar1]-ANG II were found to bind by two distinct modes to the AT1 receptor extracellular site flanked by the COOH-terminal segments of the EC-3 loop and the NH2-terminal domain. Since the [Sar1]-ligand is the most potent molecule to trigger tachyphylaxis in AT1 receptors, it was suggested that its corresponding binding mode might be associated with this special condition of receptors.
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Affiliation(s)
- Laerte Oliveira
- Department of Biophysics, Escola Paulista de Medicina, Federal University of São Paulo, Brazil.
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