1
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Sarkar A, Mitra A, Borics A. All-Atom Molecular Dynamics Simulations Indicated the Involvement of a Conserved Polar Signaling Channel in the Activation Mechanism of the Type I Cannabinoid Receptor. Int J Mol Sci 2023; 24:ijms24044232. [PMID: 36835641 PMCID: PMC9963961 DOI: 10.3390/ijms24044232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/12/2023] [Accepted: 02/15/2023] [Indexed: 02/23/2023] Open
Abstract
The type I cannabinoid G protein-coupled receptor (CB1, GPCR) is an intensely investigated pharmacological target, owing to its involvement in numerous physiological functions as well as pathological processes such as cancers, neurodegenerative diseases, metabolic disorders and neuropathic pain. In order to develop modern medications that exert their effects through binding to the CB1 receptor, it is essential to understand the structural mechanism of activation of this protein. The pool of atomic resolution experimental structures of GPCRs has been expanding rapidly in the past decade, providing invaluable information about the function of these receptors. According to the current state of the art, the activity of GPCRs involves structurally distinct, dynamically interconverting functional states and the activation is controlled by a cascade of interconnecting conformational switches in the transmembrane domain. A current challenge is to uncover how different functional states are activated and what specific ligand properties are responsible for the selectivity towards those different functional states. Our recent studies of the μ-opioid and β2-adrenergic receptors (MOP and β2AR, respectively) revealed that the orthosteric binding pockets and the intracellular surfaces of these receptors are connected through a channel of highly conserved polar amino acids whose dynamic motions are in high correlation in the agonist- and G protein-bound active states. This and independent literature data led us to hypothesize that, in addition to consecutive conformational transitions, a shift of macroscopic polarization takes place in the transmembrane domain, which is furnished by the rearrangement of polar species through their concerted movements. Here, we examined the CB1 receptor signaling complexes utilizing microsecond scale, all-atom molecular dynamics (MD) simulations in order to see if our previous assumptions could be applied to the CB1 receptor too. Apart from the identification of the previously proposed general features of the activation mechanism, several specific properties of the CB1 have been indicated that could possibly be associated with the signaling profile of this receptor.
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Affiliation(s)
- Arijit Sarkar
- Laboratory of Chemical Biology, Institute of Biochemistry, Biological Research Centre, 62 Temesvári krt., H-6726 Szeged, Hungary
- Theoretical Medicine Doctoral School, Faculty of Medicine, University of Szeged, 97 Tisza L. krt., H-6722 Szeged, Hungary
| | - Argha Mitra
- Laboratory of Chemical Biology, Institute of Biochemistry, Biological Research Centre, 62 Temesvári krt., H-6726 Szeged, Hungary
- Theoretical Medicine Doctoral School, Faculty of Medicine, University of Szeged, 97 Tisza L. krt., H-6722 Szeged, Hungary
| | - Attila Borics
- Laboratory of Chemical Biology, Institute of Biochemistry, Biological Research Centre, 62 Temesvári krt., H-6726 Szeged, Hungary
- Correspondence: ; Tel.: +36-62-599-600 (ext. 430)
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2
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Wang X, Jespers W, de Waal JJ, Wolff KAN, van Uden L, IJzerman AP, van Westen GJP, Heitman LH. Cancer-related somatic mutations alter adenosine A 1 receptor pharmacology-A focus on mutations in the loops and C-terminus. FASEB J 2022; 36:e22358. [PMID: 35604751 DOI: 10.1096/fj.202200203rr] [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: 02/07/2022] [Revised: 05/03/2022] [Accepted: 05/07/2022] [Indexed: 11/11/2022]
Abstract
G protein-coupled receptors (GPCRs) are known to be involved in tumor progression and metastasis. The adenosine A1 receptor (A1 AR) has been detected to be over-expressed in various cancer cell lines. However, the role of A1 AR in tumor development is not yet well characterized. A series of A1 AR mutations were identified in the Cancer Genome Atlas from cancer patient samples. In this study, we have investigated the pharmacology of mutations located outside of the 7-transmembrane domain by using a "single-GPCR-one-G protein" yeast system. Concentration-growth curves were obtained with the full agonist CPA for 12 mutant receptors and compared to the wild-type hA1 AR. Most mutations located at the extracellular loops (EL) reduced the levels of constitutive activity of the receptor and agonist potency. For mutants at the intracellular loops (ILs) of the receptor, an increased constitutive activity was found for mutant receptor L211R5.69 , while a decreased constitutive activity and agonist response were found for mutant receptor L113F34.51 . Lastly, mutations identified on the C-terminus did not significantly influence the pharmacological function of the receptor. A selection of mutations was also investigated in a mammalian system. Overall, similar effects on receptor activation compared to the yeast system were found with mutations located at the EL, but some contradictory effects were observed for mutations located at the IL. Taken together, this study will enrich the insight of A1 AR structure and function, enlightening the consequences of these mutations in cancer. Ultimately, this may provide potential precision medicine in cancer treatment.
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Affiliation(s)
- Xuesong Wang
- Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden, the Netherlands
| | - Willem Jespers
- Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden, the Netherlands
| | - Just J de Waal
- Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden, the Netherlands
| | - Kim A N Wolff
- Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden, the Netherlands
| | - Liedeke van Uden
- Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden, the Netherlands
| | - Adriaan P IJzerman
- Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden, the Netherlands
| | - Gerard J P van Westen
- Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden, the Netherlands
| | - Laura H Heitman
- Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden, the Netherlands.,Oncode Institute, Leiden, the Netherlands
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3
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Plouffe B, Karamitri A, Flock T, Gallion JM, Houston S, Daly CA, Bonnefond A, Guillaume JL, Le Gouill C, Froguel P, Lichtarge O, Deupi X, Jockers R, Bouvier M. Structural Elements Directing G Proteins and β-Arrestin Interactions with the Human Melatonin Type 2 Receptor Revealed by Natural Variants. ACS Pharmacol Transl Sci 2022; 5:89-101. [PMID: 35846981 PMCID: PMC9281605 DOI: 10.1021/acsptsci.1c00239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
G protein-coupled receptors (GPCRs) can engage distinct subsets of signaling pathways, but the structural determinants of this functional selectivity remain elusive. The naturally occurring genetic variants of GPCRs, selectively affecting different pathways, offer an opportunity to explore this phenomenon. We previously identified 40 coding variants of the MTNR1B gene encoding the melatonin MT2 receptor (MT2). These mutations differently impact the β-arrestin 2 recruitment, ERK activation, cAMP production, and Gαi1 and Gαz activation. In this study, we combined functional clustering and structural modeling to delineate the molecular features controlling the MT2 functional selectivity. Using non-negative matrix factorization, we analyzed the signaling signatures of the 40 MT2 variants yielding eight clusters defined by unique signaling features and localized in distinct domains of MT2. Using computational homology modeling, we describe how specific mutations can selectively affect the subsets of signaling pathways and offer a proof of principle that natural variants can be used to explore and understand the GPCR functional selectivity.
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Affiliation(s)
- Bianca Plouffe
- Department
of Biochemistry and Molecular Medicine, Université de Montréal, H3T 1J4 Montréal, Québec, Canada,Institute
for Research in Immunology and Cancer, Université
de Montréal, H3T 1J4 Montréal, Québec, Canada,The Wellcome-Wolfson
Institute for Experimental Medicine, Queen’s
University Belfast, BT9 7BL Belfast, U.K.
| | - Angeliki Karamitri
- Université
de Paris, Institut Cochin, INSERM, CNRS, F-75014 Paris, France
| | - Tilman Flock
- Laboratory
of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland,Department
of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Jonathan M. Gallion
- Program
in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, 77030 Houston, Texas, United States
| | - Shane Houston
- The Wellcome-Wolfson
Institute for Experimental Medicine, Queen’s
University Belfast, BT9 7BL Belfast, U.K.
| | - Carole A. Daly
- The Wellcome-Wolfson
Institute for Experimental Medicine, Queen’s
University Belfast, BT9 7BL Belfast, U.K.
| | - Amélie Bonnefond
- Université
de Lille, INSERM/CNRS UMR 1283/8199—EGID, Institut Pasteur
de Lille, CHU de Lille, 59045 Lille, France
| | - Jean-Luc Guillaume
- Université
de Paris, Institut Cochin, INSERM, CNRS, F-75014 Paris, France
| | - Christian Le Gouill
- Institute
for Research in Immunology and Cancer, Université
de Montréal, H3T 1J4 Montréal, Québec, Canada
| | - Phillipe Froguel
- Université
de Lille, INSERM/CNRS UMR 1283/8199—EGID, Institut Pasteur
de Lille, CHU de Lille, 59045 Lille, France
| | - Olivier Lichtarge
- Program
in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, 77030 Houston, Texas, United States,Department
of Molecular and Human Genetics, Baylor
College of Medicine, 77030 Houston, Texas, United States
| | - Xavier Deupi
- Laboratory
of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland,Condensed
Matter Theory Group, Division of Scientific Computing, Theory, and
Data, Paul Scherrer Institute, 5232 Villigen, Switzerland,. Phone: +41-563103337
| | - Ralf Jockers
- Université
de Paris, Institut Cochin, INSERM, CNRS, F-75014 Paris, France,. Phone: +33-140516434
| | - Michel Bouvier
- Department
of Biochemistry and Molecular Medicine, Université de Montréal, H3T 1J4 Montréal, Québec, Canada,Institute
for Research in Immunology and Cancer, Université
de Montréal, H3T 1J4 Montréal, Québec, Canada,. Phone: 1-514-343-6319
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4
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Geng S, Xu T, Sun Y. Genome-wide identification and analysis of chemokine receptor superfamily in miiuy croaker, Miichthys miiuy. FISH & SHELLFISH IMMUNOLOGY 2021; 118:343-353. [PMID: 34555531 DOI: 10.1016/j.fsi.2021.09.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 09/16/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
The chemokine receptor (ChemR) superfamily, which is divided into 4 subfamilies (CXCR, CCR, XCR, and CX3CR), is the main receptors of chemokines in innate immune responses. In the current study, we have identified 27 ChemRs in miiuy croaker: 13 CCR genes, 11 CXCR genes, and 3 XCR genes. Multiple characteristics of these genes, including phylogeny, gene structures, conserved motifs, chromosome locations, evolutionary mechanism, and expression levels upon the bacterial challenge were analyzed. Gene structure and location analysis showed that all ChemR genes contain fewer introns (≤4) and they are unevenly distributed on the 12 chromosomes. And the XCR subfamily of miiuy croaker don't have the DRY motif of ChemR. Phylogenetic and synteny analysis showed that these genes experienced tandem and segmental duplication event in several species, and tandem duplication might be the main expansion way in miiuy croaker. The major ChemRs of each orthologous group in vertebrates were selected for molecular evolution analysis, the results of which indicated that compared with vertebrates, ChemRs of teleost fishes may have a relatively high evolutionary dynamic. In addition, a total of 21 positively selected codons were detected in vertebrate ChemRs under Model 8. RNA-Seq analysis and qRT-PCR verification demonstrated that CXCR3.2, CXCR5, and XCR1 genes were up-regulated significantly upon the Vibrio harveyi infection. These results provide valuable information for investigating the evolutionary relationships of chemokine receptor superfamily in miiuy croaker and laid the basis for further functional analysis.
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Affiliation(s)
- Shang Geng
- Laboratory of Fish Molecular Immunology, College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China
| | - Tianjun Xu
- Laboratory of Fish Molecular Immunology, College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China; Laboratory of Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China; National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, China
| | - Yuena Sun
- Laboratory of Fish Molecular Immunology, College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources (Shanghai Ocean University), Ministry of Education, China.
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5
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Universal Properties and Specificities of the β 2-Adrenergic Receptor-G s Protein Complex Activation Mechanism Revealed by All-Atom Molecular Dynamics Simulations. Int J Mol Sci 2021; 22:ijms221910423. [PMID: 34638767 PMCID: PMC8508748 DOI: 10.3390/ijms221910423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/23/2021] [Accepted: 09/23/2021] [Indexed: 11/16/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are transmembrane proteins of high pharmacological relevance. It has been proposed that their activity is linked to structurally distinct, dynamically interconverting functional states and the process of activation relies on an interconnecting network of conformational switches in the transmembrane domain. However, it is yet to be uncovered how ligands with different extents of functional effect exert their actions. According to our recent hypothesis, based on indirect observations and the literature data, the transmission of the external stimulus to the intracellular surface is accompanied by the shift of macroscopic polarization in the transmembrane domain, furnished by concerted movements of highly conserved polar motifs and the rearrangement of polar species. In this follow-up study, we have examined the β2-adrenergic receptor (β2AR) to see if our hypothesis drawn from an extensive study of the μ-opioid receptor (MOP) is fundamental and directly transferable to other class A GPCRs. We have found that there are some general similarities between the two receptors, in agreement with previous studies, and there are some receptor-specific differences that could be associated with different signaling pathways.
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6
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Correlated Motions of Conserved Polar Motifs Lay out a Plausible Mechanism of G Protein-Coupled Receptor Activation. Biomolecules 2021; 11:biom11050670. [PMID: 33946214 PMCID: PMC8146931 DOI: 10.3390/biom11050670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/17/2021] [Accepted: 04/28/2021] [Indexed: 02/01/2023] Open
Abstract
Recent advancements in the field of experimental structural biology have provided high-resolution structures of active and inactive state G protein-coupled receptors (GPCRs), a highly important pharmaceutical target family, but the process of transition between these states is poorly understood. According to the current theory, GPCRs exist in structurally distinct, dynamically interconverting functional states of which populations are shifted upon binding of ligands and intracellular signaling proteins. However, explanation of the activation mechanism, on an entirely structural basis, gets complicated when multiple activation pathways and active receptor states are considered. Our unbiased, atomistic molecular dynamics simulations of the μ opioid receptor (MOP) revealed that transmission of external stimulus to the intracellular surface of the receptor is accompanied by subtle, concerted movements of highly conserved polar amino acid side chains along the 7th transmembrane helix. This may entail the rearrangement of polar species and the shift of macroscopic polarization in the transmembrane domain, triggered by agonist binding. Based on our observations and numerous independent indications, we suggest amending the widely accepted theory that the initiation event of GPCR activation is the shift of macroscopic polarization between the ortho- and allosteric binding pockets and the intracellular G protein-binding interface.
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7
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Wang X, van Westen GJP, Heitman LH, IJzerman AP. G protein-coupled receptors expressed and studied in yeast. The adenosine receptor as a prime example. Biochem Pharmacol 2020; 187:114370. [PMID: 33338473 DOI: 10.1016/j.bcp.2020.114370] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/11/2020] [Accepted: 12/11/2020] [Indexed: 11/25/2022]
Abstract
G protein-coupled receptors (GPCRs) are the largest class of membrane proteins with around 800 members in the human genome/proteome. Extracellular signals such as hormones and neurotransmitters regulate various biological processes via GPCRs, with GPCRs being the bodily target of 30-40% of current drugs on the market. Complete identification and understanding of GPCR functionality will provide opportunities for novel drug discovery. Yeast expresses three different endogenous GPCRs regulating pheromone and sugar sensing, with the pheromone pathway offering perspectives for the characterization of heterologous GPCR signaling. Moreover, yeast offers a ''null" background for studies on mammalian GPCRs, including GPCR activation and signaling, ligand identification, and characterization of disease-related mutations. This review focuses on modifications of the yeast pheromone signaling pathway for functional GPCR studies, and on opportunities and usage of the yeast system as a platform for human GPCR studies. Finally, this review discusses in some further detail studies of adenosine receptors heterologously expressed in yeast, and what Geoff Burnstock thought of this approach.
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Affiliation(s)
- Xuesong Wang
- Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Gerard J P van Westen
- Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Laura H Heitman
- Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Einsteinweg 55, 2333 CC Leiden, The Netherlands; Oncode Institute, Leiden, The Netherlands
| | - Adriaan P IJzerman
- Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Einsteinweg 55, 2333 CC Leiden, The Netherlands
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8
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Characterization of cancer-related somatic mutations in the adenosine A2B receptor. Eur J Pharmacol 2020; 880:173126. [DOI: 10.1016/j.ejphar.2020.173126] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 04/16/2020] [Accepted: 04/20/2020] [Indexed: 01/10/2023]
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9
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Pandey A, LeBlanc DM, Parmar HB, Phạm TTT, Sarker M, Xu L, Duncan R, Liu XQ, Rainey JK. Structure, amphipathy, and topology of the membrane-proximal helix 8 influence apelin receptor plasma membrane localization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:183036. [PMID: 31394100 DOI: 10.1016/j.bbamem.2019.183036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 07/08/2019] [Accepted: 08/02/2019] [Indexed: 12/11/2022]
Abstract
G-protein coupled receptors (GPCRs) typically have an amphipathic helix ("helix 8") immediately C-terminal to the transmembrane helical bundle. To date, a number of functional roles have been associated with GPCR helix 8 segments, but structure-function analysis for this region remains limited. Here, we examine helix 8 of the apelin receptor (AR or APJ), a class A GPCR with wide physiological and pathophysiological relevance. The 71 residue C-terminal tail of the AR is primarily intrinsically disordered, with a detergent micelle-induced increase in helical character. This helicity was localized to the helix 8 region, in good agreement with the recent AR crystal structure. A series of helix 8 mutants were made to reduce helicity, remove amphipathy, or flip the hydrophobic and hydrophilic faces. Each mutant AR was tested both biophysically, in the isolated C-terminal tail, and functionally in HEK 293 T cells, for full-length AR. In all instances, micelle interactions were maintained, and steady-state AR expression was efficient. However, removal of amphipathy or helical character led to a significant decrease in cell surface localization. Flipping of helix 8 amphipathic topology restored cell surface localization to some degree, but still was significantly reduced relative to wild-type. Structural integrity, amphipathy to drive membrane association, and correct topology of helix 8 membrane association all thus appear important for cell surface localization of the AR. This behavior correlates well to GPCR C-terminal tail sequence motifs, implying that these serve to specify key topological features of helix 8 and its proximity to the transmembrane domain.
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Affiliation(s)
- Aditya Pandey
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Danielle M LeBlanc
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Hirendrasinh B Parmar
- Department of Microbiology & Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Trần Thanh Tâm Phạm
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Muzaddid Sarker
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Microbiology & Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Lingling Xu
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Roy Duncan
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Microbiology & Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Xiang-Qin Liu
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Jan K Rainey
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
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10
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Ragnarsson L, Andersson Å, Thomas WG, Lewis RJ. Mutations in the NPxxY motif stabilize pharmacologically distinct conformational states of the α 1B- and β 2-adrenoceptors. Sci Signal 2019; 12:12/572/eaas9485. [PMID: 30862702 DOI: 10.1126/scisignal.aas9485] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
G protein-coupled receptors (GPCRs) convert extracellular stimuli to intracellular responses that regulate numerous physiological processes. Crystallographic and biophysical advances in GPCR structural analysis have aided investigations of structure-function relationships that clarify our understanding of these dynamic receptors, but the molecular mechanisms associated with activation and signaling for individual GPCRs may be more complex than was previously appreciated. Here, we investigated the proposed water-mediated, hydrogen-bonded activation switch between the conserved NPxxY motif on transmembrane helix 7 (TMH7) and a conserved tyrosine in TMH5, which contributes to α1B-adrenoceptor (α1B-AR) and β2-AR activation. Disrupting this bond by mutagenesis stabilized the α1B-AR and the β2-AR in inactive-state conformations, which displayed decreased agonist potency for stimulating downstream IP1 and cAMP signaling, respectively. Compared to that for wild-type receptors, agonist-mediated β-arrestin recruitment was substantially reduced or abolished for all α1B-AR and β2-AR inactive-state mutants. However, the inactive-state β2-ARs exhibited decreased agonist affinity, whereas the inactive-state α1B-ARs had enhanced agonist affinity. Conversely, antagonist affinity was unchanged for inactive-state conformations of both α1B-AR and β2-AR. Removing the influence of agonist affinity on agonist potency gave a measure of signaling efficacy, which was markedly decreased for the α1B-AR mutants but little altered for the β2-AR mutants. These findings highlight the pharmacological heterogeneity of inactive-state GPCR conformations, which may facilitate the rational design of drugs that target distinct conformational states of GPCRs.
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Affiliation(s)
- Lotten Ragnarsson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia.
| | - Åsa Andersson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Walter G Thomas
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia.
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11
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Coupling of Human Rhodopsin to a Yeast Signaling Pathway Enables Characterization of Mutations Associated with Retinal Disease. Genetics 2018; 211:597-615. [PMID: 30514708 DOI: 10.1534/genetics.118.301733] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 11/29/2018] [Indexed: 12/24/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are crucial sensors of extracellular signals in eukaryotes, with multiple GPCR mutations linked to human diseases. With the growing number of sequenced human genomes, determining the pathogenicity of a mutation is challenging, but can be aided by a direct measurement of GPCR-mediated signaling. This is particularly difficult for the visual pigment rhodopsin-a GPCR activated by light-for which hundreds of mutations have been linked to inherited degenerative retinal diseases such as retinitis pigmentosa. In this study, we successfully engineered, for the first time, activation by human rhodopsin of the yeast mating pathway, resulting in signaling via a fluorescent reporter. We combine this novel assay for rhodopsin light-dependent activation with studies of subcellular localization, and the upregulation of the unfolded protein response in response to misfolded rhodopsin protein. We use these assays to characterize a panel of rhodopsin mutations with known molecular phenotypes, finding that rhodopsin maintains a similar molecular phenotype in yeast, with some interesting differences. Furthermore, we compare our assays in yeast with clinical phenotypes from patients with novel disease-linked mutations. We demonstrate that our engineered yeast strain can be useful in rhodopsin mutant classification, and in helping to determine the molecular mechanisms underlying their pathogenicity. This approach may also be applied to better understand the clinical relevance of other human GPCR mutations, furthering the use of yeast as a tool for investigating molecular mechanisms relevant to human disease.
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12
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Cheng JX, Cheng T, Li WH, Liu GX, Zhu WL, Tang Y. Computational insights into the G-protein-biased activation and inactivation mechanisms of the μ opioid receptor. Acta Pharmacol Sin 2018; 39:154-164. [PMID: 29188799 DOI: 10.1038/aps.2017.158] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 08/01/2017] [Indexed: 12/30/2022] Open
Abstract
The μ opioid receptor (OR), a member of the class A subfamily of G-protein coupled receptors (GPCRs), is a major target for the treatment of pain. G-protein biased μ-OR agonists promise to be developed as analgesics. Thus, TRV130, the first representative μ-OR ligand with G-protein bias, has entered into phase III clinical trials. To identify the detailed G-protein-biased activation and inactivation mechanisms of the μ-OR, we constructed five μ-OR systems that were in complexes with the G-protein-biased agonists TRV130 and BU72, the antagonists β-FNA and naltrexone, as well as the free receptor. We performed a series of conventional molecular dynamics simulations and analyses of G-protein-biased activation and inactivation mechanisms of μ-OR. Our results, together with previously reported mutation results, revealed the operating mode of the activation switch composed of residues W6.48 and Y7.43 (Ballesteros/Weinstein numbering), the activity of which was responsible for down- and up-regulation, respectively, of the β-arrestin signaling, which in turn affected G-protein-biased activation of μ-OR. TRV130 was found to stabilize W6.48 by interacting with Y7.43. In addition, we obtained useful information regarding μ-OR-biased activation, such as strong stabilization of W7.35 through a hydrophobic ring interaction in the TRV130 system. These findings may facilitate understanding of μ-OR biased activation and the design of new biased ligands for GPCRs.
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13
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Liu R, Wong W, IJzerman AP. Human G protein-coupled receptor studies in Saccharomyces cerevisiae. Biochem Pharmacol 2016; 114:103-15. [DOI: 10.1016/j.bcp.2016.02.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 02/12/2016] [Indexed: 12/22/2022]
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14
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Jaberi E, Rohani M, Shahidi GA, Nafissi S, Arefian E, Soleimani M, Moghadam A, Arzenani MK, Keramatian F, Klotzle B, Fan JB, Turk C, Steemers F, Elahi E. Mutation inADORA1identified as likely cause of early-onset parkinsonism and cognitive dysfunction. Mov Disord 2016; 31:1004-11. [DOI: 10.1002/mds.26627] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 02/10/2016] [Accepted: 02/28/2016] [Indexed: 11/09/2022] Open
Affiliation(s)
- Elham Jaberi
- School of Biology, College of Science, University of Tehran; Tehran Iran
| | - Mohammad Rohani
- Department of Neurology; Hazrat Rasool Hospital, Iran University of Medical Sciences; Tehran Iran
| | - Gholam Ali Shahidi
- Department of Neurology; Hazrat Rasool Hospital, Iran University of Medical Sciences; Tehran Iran
| | - Shahriar Nafissi
- Department of Neurology; Tehran University of Medical Sciences; Tehran Iran
| | - Ehsan Arefian
- School of Biology, College of Science, University of Tehran; Tehran Iran
| | - Masoud Soleimani
- School of Medical Sciences; Tarbiat Modares University; Tehran Iran
| | - Abolfazl Moghadam
- School of Biology, College of Science, University of Tehran; Tehran Iran
| | | | - Farid Keramatian
- Department of Biotechnology; College of Science, University of Tehran; Tehran Iran
| | | | | | | | | | - Elahe Elahi
- School of Biology, College of Science, University of Tehran; Tehran Iran
- Department of Biotechnology; College of Science, University of Tehran; Tehran Iran
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15
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The role of the C-terminus of the human hydroxycarboxylic acid receptors 2 and 3 in G protein activation using Gα-engineered yeast cells. Eur J Pharmacol 2016; 770:70-7. [DOI: 10.1016/j.ejphar.2015.11.052] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 11/25/2015] [Accepted: 11/27/2015] [Indexed: 12/20/2022]
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