1
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Jang W, Senarath K, Lu S, Lambert NA. Visualization of endogenous G proteins on endosomes and other organelles. bioRxiv 2024:2024.03.05.583500. [PMID: 38496652 PMCID: PMC10942389 DOI: 10.1101/2024.03.05.583500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Classical G protein-coupled receptor (GPCR) signaling takes place in response to extracellular stimuli and involves receptors and heterotrimeric G proteins located at the plasma membrane. It has recently been established that GPCR signaling can also take place from intracellular membrane compartments, including endosomes that contain internalized receptors and ligands. While the mechanisms of GPCR endocytosis are well understood, it is not clear how internalized receptors are supplied with G proteins. To address this gap we use gene editing, confocal microscopy, and bioluminescence resonance energy transfer to study the distribution and trafficking of endogenous G proteins. We show here that constitutive endocytosis is sufficient to supply newly internalized endocytic vesicles with 20-30% of the G protein density found at the plasma membrane. We find that G proteins are present on early, late, and recycling endosomes, are abundant on lysosomes, but are virtually undetectable on the endoplasmic reticulum, mitochondria, and the medial Golgi apparatus. Receptor activation does not change heterotrimer abundance on endosomes. Our results provide a detailed subcellular map of endogenous G protein distribution, suggest that G proteins may be partially excluded from nascent endocytic vesicles, and are likely to have implications for GPCR signaling from endosomes and other intracellular compartments.
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Affiliation(s)
- Wonjo Jang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Kanishka Senarath
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Sumin Lu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
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2
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Xu X, Lambert NA, Wu G. Sequence-directed concentration of G protein-coupled receptors in COPII vesicles. iScience 2023; 26:107969. [PMID: 37810244 PMCID: PMC10551652 DOI: 10.1016/j.isci.2023.107969] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 06/02/2023] [Accepted: 09/15/2023] [Indexed: 10/10/2023] Open
Abstract
G protein-coupled receptors (GPCRs) constitute the largest superfamily of plasma membrane signaling proteins. However, virtually nothing is known about their recruitment to COPII vesicles for forward delivery after synthesis in the endoplasmic reticulum (ER). Here, we demonstrate that some GPCRs are highly concentrated at ER exit sites (ERES) before COPII budding. Angiotensin II type 2 receptor (AT2R) and CXCR4 concentration are directed by a di-acidic motif and a 9-residue domain, respectively, and these motifs also control receptor ER-Golgi traffic. We further show that AT2R interacts with Sar1 GTPase and that distinct GPCRs have different ER-Golgi transport rates via COPII which is independent of their concentration at ERES. Collectively, these data demonstrate that GPCRs can be actively captured by COPII via specific motifs and direct interaction with COPII components that in turn affects their export dynamics, and provide important insights into COPII targeting and forward trafficking of nascent GPCRs.
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Affiliation(s)
- Xin Xu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Nevin A. Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
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3
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Wright SC, Motso A, Koutsilieri S, Beusch CM, Sabatier P, Berghella A, Blondel-Tepaz É, Mangenot K, Pittarokoilis I, Sismanoglou DC, Le Gouill C, Olsen JV, Zubarev RA, Lambert NA, Hauser AS, Bouvier M, Lauschke VM. GLP-1R signaling neighborhoods associate with the susceptibility to adverse drug reactions of incretin mimetics. Nat Commun 2023; 14:6243. [PMID: 37813859 PMCID: PMC10562414 DOI: 10.1038/s41467-023-41893-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 09/19/2023] [Indexed: 10/11/2023] Open
Abstract
G protein-coupled receptors are important drug targets that engage and activate signaling transducers in multiple cellular compartments. Delineating therapeutic signaling from signaling associated with adverse events is an important step towards rational drug design. The glucagon-like peptide-1 receptor (GLP-1R) is a validated target for the treatment of diabetes and obesity, but drugs that target this receptor are a frequent cause of adverse events. Using recently developed biosensors, we explored the ability of GLP-1R to activate 15 pathways in 4 cellular compartments and demonstrate that modifications aimed at improving the therapeutic potential of GLP-1R agonists greatly influence compound efficacy, potency, and safety in a pathway- and compartment-selective manner. These findings, together with comparative structure analysis, time-lapse microscopy, and phosphoproteomics, reveal unique signaling signatures for GLP-1R agonists at the level of receptor conformation, functional selectivity, and location bias, thus associating signaling neighborhoods with functionally distinct cellular outcomes and clinical consequences.
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Affiliation(s)
- Shane C Wright
- Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden.
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, H3T 1J4, Canada.
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC, H3T 1J4, Canada.
| | - Aikaterini Motso
- Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Stefania Koutsilieri
- Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Christian M Beusch
- Chemistry I, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, 17177, Sweden
| | - Pierre Sabatier
- Chemistry I, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, 17177, Sweden
- Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
- Department of Surgical Sciences, Uppsala University, Uppsala, 75185, Sweden
| | - Alessandro Berghella
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Faculty of Bioscience and Agro-Food and Environmental Technology, University of Teramo, Teramo, 64100, Italy
| | - Élodie Blondel-Tepaz
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, H3T 1J4, Canada
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC, H3T 1J4, Canada
| | - Kimberley Mangenot
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, H3T 1J4, Canada
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC, H3T 1J4, Canada
| | | | | | - Christian Le Gouill
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, H3T 1J4, Canada
| | - Jesper V Olsen
- Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Roman A Zubarev
- Chemistry I, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, 17177, Sweden
- Department of Pharmacological & Technological Chemistry, I.M. Sechenov First Moscow State Medical University, Moscow, 119146, Russia
- The National Medical Research Center for Endocrinology, Moscow, 115478, Russia
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Alexander S Hauser
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michel Bouvier
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, H3T 1J4, Canada.
| | - Volker M Lauschke
- Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden.
- Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany.
- University of Tübingen, Tübingen, Germany.
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Zheng C, Javitch JA, Lambert NA, Donthamsetti P, Gurevich VV. In-Cell Arrestin-Receptor Interaction Assays. Curr Protoc 2023; 3:e890. [PMID: 37787634 PMCID: PMC10566372 DOI: 10.1002/cpz1.890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
G protein-coupled receptors (GPCRs) represent ∼30% of current drug targets. Ligand binding to these receptors activates G proteins and arrestins, which function in different signaling pathways. Given that functionally selective or biased ligands preferentially activate one of these two groups of pathways, they may be superior medications for certain disease states. The identification of such ligands requires robust drug screening assays for both G protein and arrestin activity. This unit describes protocols for assays that monitor reversible arrestin recruitment to GPCRs in living cells using either bioluminescence resonance energy transfer (BRET) or nanoluciferase complementation (NanoLuc). Two types of assays can be used: one configuration directly measures arrestin recruitment to a GPCR fused to a protein tag at its intracellular C-terminus, whereas the other configuration detects arrestin translocation to the plasma membrane in response to activation of an unmodified GPCR. Together, these assays are powerful tools for studying dynamic interactions between GPCRs and arrestins. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Receptor-arrestin BRET assay to measure ligand-induced recruitment of arrestin to receptors Basic Protocol 2: Receptor-arrestin NANOBIT assay to measure ligand-induced recruitment of arrestin to receptors Alternative Protocol 1: BRET assay to measure ligand-induced recruitment of arrestin to the plasma membrane Alternative Protocol 2: NANOBIT assay to measure ligand-induced recruitment of arrestin to the plasma membrane Support Protocol 1: Optimization of polyethylenimine (PEI) concentration for transfection.
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Affiliation(s)
- Chen Zheng
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee
| | - Jonathan A. Javitch
- Departments of Psychiatry and Molecular Pharmacology and Therapeutics, Columbia University Vagelos College of Physicians and Surgeons, New York, New York
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York
| | - Nevin A. Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia
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Petelák A, Lambert NA, Bondar A. Serotonin 5-HT 7 receptor slows down the G s protein: a single molecule perspective. Mol Biol Cell 2023; 34:br14. [PMID: 37342875 PMCID: PMC10398887 DOI: 10.1091/mbc.e23-03-0117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/23/2023] Open
Abstract
The 5-hydroxytryptamine (serotonin) receptor type 7 (5-HT7R) is a G protein-coupled receptor present primarily in the nervous system and gastrointestinal tract, where it regulates mood, cognition, digestion, and vasoconstriction. 5-HT7R has previously been shown to bind to its cognate stimulatory Gs protein in the inactive state. This phenomenon, termed "inverse coupling," is thought to counteract the atypically high intrinsic activity of 5-HT7R. However, it is not clear how active and inactive 5-HT7 receptors affect the mobility of the Gs protein in the plasma membrane. Here, we used single-molecule imaging of the Gs protein and 5-HT7R to evaluate Gs mobility in the membrane in the presence of 5-HT7R and its mutants. We show that expression of 5-HT7R dramatically reduces the diffusion rate of Gs. Expression of the constitutively active mutant 5-HT7R (L173A) is less effective at slowing Gs diffusion presumably due to the reduced ability to form long-lasting inactive complexes. An inactive 5-HT7R (N380K) mutant slows down Gs to the same extent as the wild-type receptor. We conclude that inactive 5-HT7R profoundly affects Gs mobility, which could lead to Gs redistribution in the plasma membrane and alter its availability to other G protein-coupled receptors and effectors.
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Affiliation(s)
- Aleš Petelák
- Laboratory of Structural Biology and Bioinformatics, Institute of Microbiology of the Czech Academy of Sciences, CZ-37333, Nové Hrady, Czech Republic
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA 30912
| | - Alexey Bondar
- Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia, CZ - 37005, České Budějovice, Czech Republic
- Laboratory of Microscopy and Histology, Institute of Entomology, Biology Centre of the Czech Academy of Sciences, CZ - 37005, České Budějovice, Czech Republic
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6
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Grätz L, Kowalski-Jahn M, Scharf MM, Kozielewicz P, Jahn M, Bous J, Lambert NA, Gloriam DE, Schulte G. Pathway selectivity in Frizzleds is achieved by conserved micro-switches defining pathway-determining, active conformations. Nat Commun 2023; 14:4573. [PMID: 37516754 PMCID: PMC10387068 DOI: 10.1038/s41467-023-40213-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 07/12/2023] [Indexed: 07/31/2023] Open
Abstract
The class Frizzled of G protein-coupled receptors (GPCRs), consisting of ten Frizzled (FZD1-10) paralogs and Smoothened, remains one of the most enigmatic GPCR families. This class mediates signaling predominantly through Disheveled (DVL) or heterotrimeric G proteins. However, the mechanisms underlying pathway selection are elusive. Here we employ a structure-driven mutagenesis approach in combination with an extensive panel of functional signaling readouts to investigate the importance of conserved state-stabilizing residues in FZD5 for signal specification. Similar data were obtained for FZD4 and FZD10 suggesting that our findings can be extrapolated to other members of the FZD family. Comparative molecular dynamics simulations of wild type and selected FZD5 mutants further support the concept that distinct conformational changes in FZDs specify the signal outcome. In conclusion, we find that FZD5 and FZDs in general prefer coupling to DVL rather than heterotrimeric G proteins and that distinct active state micro-switches in the receptor are essential for pathway selection arguing for conformational changes in the receptor protein defining transducer selectivity.
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Affiliation(s)
- Lukas Grätz
- Karolinska Institutet, Dept. Physiology & Pharmacology, Sec. Receptor Biology & Signaling, Biomedicum, S-17165, Stockholm, Sweden
| | - Maria Kowalski-Jahn
- Karolinska Institutet, Dept. Physiology & Pharmacology, Sec. Receptor Biology & Signaling, Biomedicum, S-17165, Stockholm, Sweden
| | - Magdalena M Scharf
- Karolinska Institutet, Dept. Physiology & Pharmacology, Sec. Receptor Biology & Signaling, Biomedicum, S-17165, Stockholm, Sweden
| | - Pawel Kozielewicz
- Karolinska Institutet, Dept. Physiology & Pharmacology, Sec. Receptor Biology & Signaling, Biomedicum, S-17165, Stockholm, Sweden
| | - Michael Jahn
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, S-17121, Solna, Sweden
- Max Planck Unit for the Science of Pathogens, Bioinformatics platform, Charitéplatz 1, D-10117, Berlin, Germany
| | - Julien Bous
- Karolinska Institutet, Dept. Physiology & Pharmacology, Sec. Receptor Biology & Signaling, Biomedicum, S-17165, Stockholm, Sweden
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - David E Gloriam
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Gunnar Schulte
- Karolinska Institutet, Dept. Physiology & Pharmacology, Sec. Receptor Biology & Signaling, Biomedicum, S-17165, Stockholm, Sweden.
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7
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Abstract
G protein-coupled receptors (GPCRs) selectively activate at least one of the four families of heterotrimeric G proteins, but the mechanism of coupling selectivity remains unclear. Structural studies emphasize structural complementarity of GPCRs and nucleotide-free G proteins, but selectivity is likely to be determined by transient intermediate-state complexes that exist before nucleotide release. Here we study coupling to nucleotide-decoupled G protein variants that can adopt conformations similar to receptor-bound G proteins without releasing nucleotide, and are therefore able to bypass intermediate-state complexes. We find that selectivity is degraded when nucleotide release is not required for GPCR-G protein complex formation, to the extent that most GPCRs interact with most nucleotide-decoupled G proteins. These findings demonstrate the absence of absolute structural incompatibility between noncognate receptor-G protein pairs, and are consistent with the hypothesis that transient intermediate states are partly responsible for coupling selectivity.
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Affiliation(s)
- Wonjo Jang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA.
| | - Sumin Lu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Xin Xu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA.
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8
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Lee A, Lebedyeva I, Zhi W, Senthil V, Cheema H, Brands MW, Bush W, Lambert NA, Snipes M, Browning DD. A Non-Systemic Phosphodiesterase-5 Inhibitor Suppresses Colon Proliferation in Mice. Int J Mol Sci 2023; 24:ijms24119397. [PMID: 37298349 DOI: 10.3390/ijms24119397] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/15/2023] [Accepted: 05/17/2023] [Indexed: 06/12/2023] Open
Abstract
Phosphodiesterase-5 inhibitors (PDE5i) are under investigation for repurposing for colon cancer prevention. A drawback to conventional PDE5i are their side-effects and drug-drug interactions. We designed an analog of the prototypical PDE5i sildenafil by replacing the methyl group on the piperazine ring with malonic acid to reduce lipophilicity, and measured its entry into the circulation and effects on colon epithelium. This modification did not affect pharmacology as malonyl-sildenafil had a similar IC50 to sildenafil but exhibited an almost 20-fold reduced EC50 for increasing cellular cGMP. Using an LC-MS/MS approach, malonyl-sildenafil was negligible in mouse plasma after oral administration but was detected at high levels in the feces. No bioactive metabolites of malonyl-sildenafil were detected in the circulation by measuring interactions with isosorbide mononitrate. The treatment of mice with malonyl-sildenafil in the drinking water resulted in a suppression of proliferation in the colon epithelium that is consistent with results previously published for mice treated with PDE5i. A carboxylic-acid-containing analog of sildenafil prohibits the systemic delivery of the compound but maintains sufficient penetration into the colon epithelium to suppress proliferation. This highlights a novel approach to generating a first-in-class drug for colon cancer chemoprevention.
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Affiliation(s)
- Avelina Lee
- Department of Biochemistry and Molecular Biology, Augusta University, Augusta, GA 30912, USA
| | - Iryna Lebedyeva
- Department of Chemistry and Physics, Augusta University, Augusta, GA 30912, USA
| | - Wenbo Zhi
- Center for Biotechnology and Genomic Medicine, Augusta University, Augusta, GA 30912, USA
| | - Vani Senthil
- Department of Biochemistry and Molecular Biology, Augusta University, Augusta, GA 30912, USA
| | - Herjot Cheema
- Department of Biochemistry and Molecular Biology, Augusta University, Augusta, GA 30912, USA
| | - Michael W Brands
- Department of Physiology, Augusta University, Augusta, GA 30912, USA
| | - Weston Bush
- Department of Physiology, Augusta University, Augusta, GA 30912, USA
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA 30912, USA
| | - Madeline Snipes
- Department of Biochemistry and Molecular Biology, Augusta University, Augusta, GA 30912, USA
| | - Darren D Browning
- Department of Biochemistry and Molecular Biology, Augusta University, Augusta, GA 30912, USA
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9
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Karim JA, Lambert NA, Pioszak AA. Time- and cost-efficient bacterial expression and purification of potato apyrase. Protein Expr Purif 2023; 203:106215. [PMID: 36535546 PMCID: PMC9807108 DOI: 10.1016/j.pep.2022.106215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/12/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022]
Abstract
Apyrase from potato (Solanum tuberosum) is a divalent metal ion-dependent enzyme that catalyzes the hydrolysis of nucleoside di- and tri-phosphates with broad substrate specificity. The enzyme is widely used to manipulate nucleotide levels such as in the G protein-coupled receptor (GPCR) field where it is used to deplete guanine nucleotides to stabilize nucleotide-free ternary agonist-GPCR-G protein complexes. Potato apyrase is available commercially as the native enzyme purified from potatoes or as a recombinant protein, but these are prohibitively expensive for some research applications. Here, we report a relatively simple method for the bacterial production of soluble, active potato apyrase. Apyrase has several disulfide bonds, so we co-expressed the enzyme bearing a C-terminal (His)6 tag with the E. coli disulfide isomerase DsbC at low temperature (18 °C) in the oxidizing cytoplasm of E. coli Origami B (DE3). This allowed low level production of soluble apyrase. A two-step purification procedure involving Ni-affinity followed by Cibacron Blue-affinity chromatography yielded highly purified apyrase at a level of ∼0.5 mg per L of bacterial culture. The purified enzyme was functional for ATP hydrolysis in an ATPase assay and for GTP/GDP hydrolysis in a GPCR-G protein coupling assay. This methodology enables the time- and cost-efficient production of recombinant apyrase for various research applications.
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Affiliation(s)
- Jordan A Karim
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Augen A Pioszak
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
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Fonseca FV, Raffay TM, Xiao K, McLaughlin PJ, Qian Z, Grimmett ZW, Adachi N, Wang B, Hausladen A, Cobb BA, Zhang R, Hess DT, Gaston B, Lambert NA, Reynolds JD, Premont RT, Stamler JS. S-nitrosylation is required for β 2AR desensitization and experimental asthma. Mol Cell 2022; 82:3089-3102.e7. [PMID: 35931084 PMCID: PMC9391322 DOI: 10.1016/j.molcel.2022.06.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/18/2022] [Accepted: 06/28/2022] [Indexed: 12/22/2022]
Abstract
The β2-adrenergic receptor (β2AR), a prototypic G-protein-coupled receptor (GPCR), is a powerful driver of bronchorelaxation, but the effectiveness of β-agonist drugs in asthma is limited by desensitization and tachyphylaxis. We find that during activation, the β2AR is modified by S-nitrosylation, which is essential for both classic desensitization by PKA as well as desensitization of NO-based signaling that mediates bronchorelaxation. Strikingly, S-nitrosylation alone can drive β2AR internalization in the absence of traditional agonist. Mutant β2AR refractory to S-nitrosylation (Cys265Ser) exhibits reduced desensitization and internalization, thereby amplifying NO-based signaling, and mice with Cys265Ser mutation are resistant to bronchoconstriction, inflammation, and the development of asthma. S-nitrosylation is thus a central mechanism in β2AR signaling that may be operative widely among GPCRs and targeted for therapeutic gain.
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Affiliation(s)
- Fabio V Fonseca
- Institute for Transformative Molecular Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Thomas M Raffay
- Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Kunhong Xiao
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Precious J McLaughlin
- Institute for Transformative Molecular Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Zhaoxia Qian
- Institute for Transformative Molecular Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Zachary W Grimmett
- Institute for Transformative Molecular Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Naoko Adachi
- Institute for Transformative Molecular Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Benlian Wang
- Center for Proteomics and Bioinformatics, Department of Nutrition, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Alfred Hausladen
- Institute for Transformative Molecular Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Brian A Cobb
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Rongli Zhang
- Cardiovascular Research Institute, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Douglas T Hess
- Institute for Transformative Molecular Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Benjamin Gaston
- Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - James D Reynolds
- Institute for Transformative Molecular Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; Harrington Discovery Institute, University Hospitals Cleveland Medical Center, Cleveland, OH 44106, USA
| | - Richard T Premont
- Institute for Transformative Molecular Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; Harrington Discovery Institute, University Hospitals Cleveland Medical Center, Cleveland, OH 44106, USA
| | - Jonathan S Stamler
- Institute for Transformative Molecular Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; Harrington Discovery Institute, University Hospitals Cleveland Medical Center, Cleveland, OH 44106, USA.
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11
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Asher WB, Terry DS, Gregorio GGA, Kahsai AW, Borgia A, Xie B, Modak A, Zhu Y, Jang W, Govindaraju A, Huang LY, Inoue A, Lambert NA, Gurevich VV, Shi L, Lefkowitz RJ, Blanchard SC, Javitch JA. GPCR-mediated β-arrestin activation deconvoluted with single-molecule precision. Cell 2022; 185:1661-1675.e16. [PMID: 35483373 PMCID: PMC9191627 DOI: 10.1016/j.cell.2022.03.042] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 02/11/2022] [Accepted: 03/29/2022] [Indexed: 01/14/2023]
Abstract
β-arrestins bind G protein-coupled receptors to terminate G protein signaling and to facilitate other downstream signaling pathways. Using single-molecule fluorescence resonance energy transfer imaging, we show that β-arrestin is strongly autoinhibited in its basal state. Its engagement with a phosphopeptide mimicking phosphorylated receptor tail efficiently releases the β-arrestin tail from its N domain to assume distinct conformations. Unexpectedly, we find that β-arrestin binding to phosphorylated receptor, with a phosphorylation barcode identical to the isolated phosphopeptide, is highly inefficient and that agonist-promoted receptor activation is required for β-arrestin activation, consistent with the release of a sequestered receptor C tail. These findings, together with focused cellular investigations, reveal that agonism and receptor C-tail release are specific determinants of the rate and efficiency of β-arrestin activation by phosphorylated receptor. We infer that receptor phosphorylation patterns, in combination with receptor agonism, synergistically establish the strength and specificity with which diverse, downstream β-arrestin-mediated events are directed.
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Affiliation(s)
- Wesley B Asher
- Department of Psychiatry, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Daniel S Terry
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - G Glenn A Gregorio
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065, USA
| | - Alem W Kahsai
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA; Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Alessandro Borgia
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Bing Xie
- Computational Chemistry and Molecular Biophysics Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | - Arnab Modak
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Ying Zhu
- Department of Psychiatry, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Wonjo Jang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Alekhya Govindaraju
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Li-Yin Huang
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA; Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | | | - Lei Shi
- Computational Chemistry and Molecular Biophysics Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | - Robert J Lefkowitz
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA; Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA; Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Scott C Blanchard
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065, USA.
| | - Jonathan A Javitch
- Department of Psychiatry, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA; Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
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12
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Abstract
A large number of GPCRs are potentially valuable drug targets but remain understudied. Many of these lack well-validated activating ligands and are considered “orphan” receptors, and G protein coupling profiles have not been defined for many orphan GPCRs. Here we asked if constitutive receptor activity can be used to determine G protein coupling profiles of orphan GPCRs. We monitored nucleotide-sensitive interactions between 48 understudied orphan GPCRs and five G proteins (240 combinations) using bioluminescence resonance energy transfer (BRET). No receptor ligands were used, but GDP was used as a common G protein ligand to disrupt receptor-G protein complexes. Constitutive BRET between the same receptors and β-arrestins was also measured. We found sufficient GDP-sensitive BRET to generate G protein coupling profiles for 22 of the 48 receptors we studied. Altogether we identified 48 coupled receptor-G protein pairs, many of which have not been described previously. We conclude that receptor-G protein complexes that form spontaneously in the absence of guanine nucleotides can be used to profile G protein coupling of constitutively-active GPCRs. This approach may prove useful for studying G protein coupling of other GPCRs for which activating ligands are not available.
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Affiliation(s)
- Sumin Lu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, United States of America
| | - Wonjo Jang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, United States of America
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Nevin A. Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, United States of America
- * E-mail:
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13
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Bondar A, Jang W, Sviridova E, Lambert NA. Components of the G s signaling cascade exhibit distinct changes in mobility and membrane domain localization upon β 2 -adrenergic receptor activation. Traffic 2021; 21:324-332. [PMID: 32096320 DOI: 10.1111/tra.12724] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 02/21/2020] [Accepted: 02/21/2020] [Indexed: 12/12/2022]
Abstract
The G protein signaling cascade is a key player in cell signaling. Cascade activation leads to a redistribution of its members in various cellular compartments. These changes are likely related to the "second wave" of signaling from endosomes. Here, we set out to determine whether Gs signaling cascade members expressed at very low levels exhibit altered mobility and localize in clathrin-coated structures (CCSs) or caveolae upon activation by β2 -adrenergic receptors (β2 AR). Activated β2 AR showed decreased mobility and sustained accumulation in CCSs but not in caveolae. Arrestin 3 translocated to the plasma membrane after β2 AR activation and showed very low mobility and pronounced accumulation in CCSs. In contrast, Gαs and Gγ2 exhibited a modest reduction in mobility but no detectable accumulation in or exclusion from CCSs or caveolae. The effector adenylyl cyclase 5 (AC5) showed a slight mobility increase upon β2 AR stimulation, no redistribution to CCSs, and weak activation-independent accumulation in caveolae. Our findings show an overall decrease in the mobility of most activated Gs signaling cascade members and confirm that β2 AR and arrestin 3 accumulate in CCSs, while Gαs , Gγ2 and AC5 can transiently enter CCSs and caveolae but do not accumulate in and are not excluded from these domains.
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Affiliation(s)
- Alexey Bondar
- Department of Pharmacology and Toxicology, Augusta University, Augusta, Georgia, USA.,Center for Nanobiology and Structural Biology, Institute of Microbiology of the Academy of Sciences of the Czech Republic, Czech Republic.,Institute of Organic Chemistry and Biochemistry of the Academy of Sciences of the Czech Republic, Prague, Czech Republic.,University of South Bohemia, Czech Republic
| | - Wonjo Jang
- Department of Pharmacology and Toxicology, Augusta University, Augusta, Georgia, USA
| | - Ekaterina Sviridova
- Center for Nanobiology and Structural Biology, Institute of Microbiology of the Academy of Sciences of the Czech Republic, Czech Republic
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Augusta University, Augusta, Georgia, USA
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14
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Khater M, Wei Z, Xu X, Huang W, Lokeshwar BL, Lambert NA, Wu G. G protein βγ translocation to the Golgi apparatus activates MAPK via p110γ-p101 heterodimers. J Biol Chem 2021; 296:100325. [PMID: 33493514 PMCID: PMC7949113 DOI: 10.1016/j.jbc.2021.100325] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/11/2021] [Accepted: 01/19/2021] [Indexed: 01/14/2023] Open
Abstract
The Golgi apparatus (GA) is a cellular organelle that plays a critical role in the processing of proteins for secretion. Activation of G protein-coupled receptors at the plasma membrane (PM) induces the translocation of G protein βγ dimers to the GA. However, the functional significance of this translocation is largely unknown. Here, we study PM-GA translocation of all 12 Gγ subunits in response to chemokine receptor CXCR4 activation and demonstrate that Gγ9 is a unique Golgi-translocating Gγ subunit. CRISPR-Cas9-mediated knockout of Gγ9 abolishes activation of extracellular signal-regulated kinase 1 and 2 (ERK1/2), two members of the mitogen-activated protein kinase family, by CXCR4. We show that chemically induced recruitment to the GA of Gβγ dimers containing different Gγ subunits activates ERK1/2, whereas recruitment to the PM is ineffective. We also demonstrate that pharmacological inhibition of phosphoinositide 3-kinase γ (PI3Kγ) and depletion of its subunits p110γ and p101 abrogate ERK1/2 activation by CXCR4 and Gβγ recruitment to the GA. Knockout of either Gγ9 or PI3Kγ significantly suppresses prostate cancer PC3 cell migration, invasion, and metastasis. Collectively, our data demonstrate a novel function for Gβγ translocation to the GA, via activating PI3Kγ heterodimers p110γ-p101, to spatiotemporally regulate mitogen-activated protein kinase activation by G protein-coupled receptors and ultimately control tumor progression.
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Affiliation(s)
- Mostafa Khater
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Zhe Wei
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Xin Xu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Wei Huang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Bal L Lokeshwar
- Georgia Cancer Center, Augusta University, Augusta, Georgia, USA
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA.
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15
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Mathiasen S, Palmisano T, Perry NA, Stoveken HM, Vizurraga A, McEwen DP, Okashah N, Langenhan T, Inoue A, Lambert NA, Tall GG, Javitch JA. G12/13 is activated by acute tethered agonist exposure in the adhesion GPCR ADGRL3. Nat Chem Biol 2020; 16:1343-1350. [PMID: 32778842 PMCID: PMC7990041 DOI: 10.1038/s41589-020-0617-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 07/08/2020] [Indexed: 02/06/2023]
Abstract
The adhesion G-protein-coupled receptor (GPCR) latrophilin 3 (ADGRL3) has been associated with increased risk of attention deficit hyperactivity disorder (ADHD) and substance use in human genetic studies. Knockdown in multiple species leads to hyperlocomotion and altered dopamine signaling. Thus, ADGRL3 is a potential target for treatment of neuropsychiatric disorders that involve dopamine dysfunction, but its basic signaling properties are poorly understood. Identification of adhesion GPCR signaling partners has been limited by a lack of tools to acutely activate these receptors in living cells. Here, we design a novel acute activation strategy to characterize ADGRL3 signaling by engineering a receptor construct in which we could trigger acute activation enzymatically. Using this assay, we found that ADGRL3 signals through G12/G13 and Gq, with G12/13 the most robustly activated. Gα12/13 is a new player in ADGRL3 biology, opening up unexplored roles for ADGRL3 in the brain. Our methodological advancements should be broadly useful in adhesion GPCR research.
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MESH Headings
- Activating Transcription Factor 6/agonists
- Activating Transcription Factor 6/chemistry
- Activating Transcription Factor 6/genetics
- Activating Transcription Factor 6/metabolism
- Animals
- Arrestin/chemistry
- Arrestin/genetics
- Arrestin/metabolism
- CRISPR-Cas Systems
- Cell Engineering
- GTP-Binding Protein alpha Subunits, G12-G13/chemistry
- GTP-Binding Protein alpha Subunits, G12-G13/genetics
- GTP-Binding Protein alpha Subunits, G12-G13/metabolism
- GTP-Binding Protein alpha Subunits, Gq-G11/chemistry
- GTP-Binding Protein alpha Subunits, Gq-G11/genetics
- GTP-Binding Protein alpha Subunits, Gq-G11/metabolism
- Gene Expression
- HEK293 Cells
- Humans
- Kinetics
- Mice
- Mitogen-Activated Protein Kinase 1/chemistry
- Mitogen-Activated Protein Kinase 1/genetics
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3/chemistry
- Mitogen-Activated Protein Kinase 3/genetics
- Mitogen-Activated Protein Kinase 3/metabolism
- Peptides/chemistry
- Peptides/metabolism
- Peptides/pharmacology
- Protein Binding
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Peptide/chemistry
- Receptors, Peptide/genetics
- Receptors, Peptide/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Signal Transduction
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Affiliation(s)
- Signe Mathiasen
- Department of Psychiatry, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Tiago Palmisano
- Department of Psychiatry, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Nicole A Perry
- Department of Psychiatry, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Hannah M Stoveken
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Alex Vizurraga
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Dyke P McEwen
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Najeah Okashah
- Department of Pharmacology and Toxicology, Augusta University Medical College of Georgia, Augusta, GA, USA
| | - Tobias Langenhan
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Augusta University Medical College of Georgia, Augusta, GA, USA
| | - Gregory G Tall
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Jonathan A Javitch
- Department of Psychiatry, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA.
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA.
- Department of Pharmacology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA.
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16
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Khater MK, Wei Z, Huang W, Lokeshwar BL, Lambert NA, Wu G. G protein βγ translocation to the Golgi activates the mitogen‐activated protein kinases via phosphoinositide 3‐kinase γ. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.05102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Zhe Wei
- Medical College of Georgia - Augusta University
| | - Wei Huang
- Medical College of Georgia - Augusta University
| | - Bal L. Lokeshwar
- Georgia Cancer Center - Augusta University
- Charlie Norwood VA Medical Center
| | | | - Guangyu Wu
- Medical College of Georgia - Augusta University
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17
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Jang W, Lambert NA. Inactive 5‐HT
7
Receptors Associate with Inactive and Active G
s
Heterotrimers. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.03446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Wonjo Jang
- Medical College of Georgia at Augusta University
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18
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Pritchard AB, Kanai SM, Krock B, Schindewolf E, Oliver-Krasinski J, Khalek N, Okashah N, Lambert NA, Tavares ALP, Zackai E, Clouthier DE. Loss-of-function of Endothelin receptor type A results in Oro-Oto-Cardiac syndrome. Am J Med Genet A 2020; 182:1104-1116. [PMID: 32133772 DOI: 10.1002/ajmg.a.61531] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 02/06/2020] [Accepted: 02/06/2020] [Indexed: 01/14/2023]
Abstract
Craniofacial morphogenesis is regulated in part by signaling from the Endothelin receptor type A (EDNRA). Pathogenic variants in EDNRA signaling pathway components EDNRA, GNAI3, PCLB4, and EDN1 cause Mandibulofacial Dysostosis with Alopecia (MFDA), Auriculocondylar syndrome (ARCND) 1, 2, and 3, respectively. However, cardiovascular development is normal in MFDA and ARCND individuals, unlike Ednra knockout mice. One explanation may be that partial EDNRA signaling remains in MFDA and ARCND, as mice with reduced, but not absent, EDNRA signaling also lack a cardiovascular phenotype. Here we report an individual with craniofacial and cardiovascular malformations mimicking the Ednra -/- mouse phenotype, including a distinctive micrognathia with microstomia and a hypoplastic aortic arch. Exome sequencing found a novel homozygous missense variant in EDNRA (c.1142A>C; p.Q381P). Bioluminescence resonance energy transfer assays revealed that this amino acid substitution in helix 8 of EDNRA prevents recruitment of G proteins to the receptor, abrogating subsequent receptor activation by its ligand, Endothelin-1. This homozygous variant is thus the first reported loss-of-function EDNRA allele, resulting in a syndrome we have named Oro-Oto-Cardiac Syndrome. Further, our results illustrate that EDNRA signaling is required for both normal human craniofacial and cardiovascular development, and that limited EDNRA signaling is likely retained in ARCND and MFDA individuals. This work illustrates a straightforward approach to identifying the functional consequence of novel genetic variants in signaling molecules associated with malformation syndromes.
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Affiliation(s)
- Amanda Barone Pritchard
- Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Stanley M Kanai
- Department of Craniofacial Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Bryan Krock
- Division of Genomic Diagnostics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Erica Schindewolf
- Center for Fetal Diagnosis and Treatment, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | | | - Nahla Khalek
- Center for Fetal Diagnosis and Treatment, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Najeah Okashah
- Department of Pharmacology and Toxicology, Medical College of Georgia-Augusta University, Augusta, Georgia, USA
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia-Augusta University, Augusta, Georgia, USA
| | - Andre L P Tavares
- Department of Craniofacial Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Elaine Zackai
- Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - David E Clouthier
- Department of Craniofacial Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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19
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Stoeber M, Jullié D, Li J, Chakraborty S, Majumdar S, Lambert NA, Manglik A, von Zastrow M. Agonist-selective recruitment of engineered protein probes and of GRK2 by opioid receptors in living cells. eLife 2020; 9:54208. [PMID: 32096468 PMCID: PMC7041944 DOI: 10.7554/elife.54208] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 01/29/2020] [Indexed: 12/21/2022] Open
Abstract
G protein-coupled receptors (GPCRs) signal through allostery, and it is increasingly clear that chemically distinct agonists can produce different receptor-based effects. It has been proposed that agonists selectively promote receptors to recruit one cellular interacting partner over another, introducing allosteric ‘bias’ into the signaling system. However, the underlying hypothesis - that different agonists drive GPCRs to engage different cytoplasmic proteins in living cells - remains untested due to the complexity of readouts through which receptor-proximal interactions are typically inferred. We describe a cell-based assay to overcome this challenge, based on GPCR-interacting biosensors that are disconnected from endogenous transduction mechanisms. Focusing on opioid receptors, we directly demonstrate differences between biosensor recruitment produced by chemically distinct opioid ligands in living cells. We then show that selective recruitment applies to GRK2, a biologically relevant GPCR regulator, through discrete interactions of GRK2 with receptors or with G protein beta-gamma subunits which are differentially promoted by agonists. About a third of all drugs work by targeting a group of proteins known as G-protein coupled receptors, or GPCRs for short. These receptors are found on the surface of cells and transmit messages across the cell’s outer barrier. When a signaling molecule, like a hormone, is released in the body, it binds to a GPCR and changes the receptor’s shape. The change in structure affects how the GPCR interacts and binds to other proteins on the inside of the cell, triggering a series of reactions that alter the cell’s activity. Scientists have previously seen that a GPCR can trigger different responses depending on which signaling molecule is binding on the surface of the cell. However, the mechanism for this is unknown. One hypothesis is that different signaling molecules change the GPCR’s preference for binding to different proteins on the inside of the cell. The challenge has been to observe this happening without interfering with the process. Stoeber et al. have now tested this idea by attaching fluorescent tags to proteins that bind to activated GPCRs directly and without binding other signaling proteins. This meant these proteins could be tracked under a microscope as they made their way to bind to the GPCRs. Stoeber et al. focused on one particular GPCR, known as the opioid receptor, and tested the binding of two different opioid signaling molecules, etorphine and Dynorphin A. The experiments revealed that the different opioids did affect which of the engineered proteins would preferentially bind to the opioid receptor. This was followed by a similar experiment, where the engineered proteins were replaced with another protein called GRK2, which binds to the opioid receptor under normal conditions in the cell. This showed that GRK2 binds much more strongly to the opioid receptor when Dynorphin A is added compared to adding etorphine. These findings show that GPCRs can not only communicate that a signaling molecule is binding but can respond differently to convey what molecule it is more specifically. This could be important in developing drugs, particularly to specifically trigger the desired response and reduce side effects. Stoeber et al. suggest that an important next step for research is to understand how the GPCRs preferentially bind to different proteins.
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Affiliation(s)
- Miriam Stoeber
- Department of Psychiatry, University of California, San Francisco, San Francisco, United States.,Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Damien Jullié
- Department of Psychiatry, University of California, San Francisco, San Francisco, United States.,Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States
| | - Joy Li
- Department of Psychiatry, University of California, San Francisco, San Francisco, United States.,Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States
| | - Soumen Chakraborty
- Center for Clinical Pharmacology, Washington University School of Medicine, St. Louis, United States.,St Louis College of Pharmacy, St. Louis, United States
| | - Susruta Majumdar
- Center for Clinical Pharmacology, Washington University School of Medicine, St. Louis, United States.,St Louis College of Pharmacy, St. Louis, United States
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, United States
| | - Aashish Manglik
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States.,Department of Anesthesia, University of California, San Francisco, San Francisco, United States
| | - Mark von Zastrow
- Department of Psychiatry, University of California, San Francisco, San Francisco, United States.,Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States
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20
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Zhuang Y, Liu H, Edward Zhou X, Kumar Verma R, de Waal PW, Jang W, Xu TH, Wang L, Meng X, Zhao G, Kang Y, Melcher K, Fan H, Lambert NA, Eric Xu H, Zhang C. Structure of formylpeptide receptor 2-G i complex reveals insights into ligand recognition and signaling. Nat Commun 2020; 11:885. [PMID: 32060286 PMCID: PMC7021761 DOI: 10.1038/s41467-020-14728-9] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 01/29/2020] [Indexed: 02/06/2023] Open
Abstract
Formylpeptide receptors (FPRs) as G protein-coupled receptors (GPCRs) can recognize formylpeptides derived from pathogens or host cells to function in host defense and cell clearance. In addition, FPRs, especially FPR2, can also recognize other ligands with a large chemical diversity generated at different stages of inflammation to either promote or resolve inflammation in order to maintain a balanced inflammatory response. The mechanism underlying promiscuous ligand recognition and activation of FPRs is not clear. Here we report a cryo-EM structure of FPR2-Gi signaling complex with a peptide agonist. The structure reveals a widely open extracellular region with an amphiphilic environment for ligand binding. Together with computational docking and simulation, the structure suggests a molecular basis for the recognition of formylpeptides and a potential mechanism of receptor activation, and reveals conserved and divergent features in Gi coupling. Our results provide a basis for understanding the molecular mechanism of the functional promiscuity of FPRs.
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Affiliation(s)
- Youwen Zhuang
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Center for Cancer and Cell Biology, Program for Structural Biology, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Heng Liu
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - X Edward Zhou
- Center for Cancer and Cell Biology, Program for Structural Biology, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Ravi Kumar Verma
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Parker W de Waal
- Center for Cancer and Cell Biology, Program for Structural Biology, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Wonjo Jang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Ting-Hai Xu
- Center for Cancer and Cell Biology, Program for Structural Biology, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Lei Wang
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Xing Meng
- David Van Andel Advanced Cryo-Electron Microscopy Suite, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Gongpu Zhao
- David Van Andel Advanced Cryo-Electron Microscopy Suite, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Yanyong Kang
- Center for Cancer and Cell Biology, Program for Structural Biology, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
- Takeda Research, 9625 Towne Centre Drive, San Diego, CA, 92130, USA
| | - Karsten Melcher
- Center for Cancer and Cell Biology, Program for Structural Biology, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Hao Fan
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - H Eric Xu
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
- Center for Cancer and Cell Biology, Program for Structural Biology, Van Andel Research Institute, Grand Rapids, MI, 49503, USA.
| | - Cheng Zhang
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, USA.
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21
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Zhou Q, Yang D, Wu M, Guo Y, Guo W, Zhong L, Cai X, Dai A, Jang W, Shakhnovich EI, Liu ZJ, Stevens RC, Lambert NA, Babu MM, Wang MW, Zhao S. Common activation mechanism of class A GPCRs. eLife 2019; 8:e50279. [PMID: 31855179 PMCID: PMC6954041 DOI: 10.7554/elife.50279] [Citation(s) in RCA: 264] [Impact Index Per Article: 52.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 12/19/2019] [Indexed: 12/26/2022] Open
Abstract
Class A G-protein-coupled receptors (GPCRs) influence virtually every aspect of human physiology. Understanding receptor activation mechanism is critical for discovering novel therapeutics since about one-third of all marketed drugs target members of this family. GPCR activation is an allosteric process that couples agonist binding to G-protein recruitment, with the hallmark outward movement of transmembrane helix 6 (TM6). However, what leads to TM6 movement and the key residue level changes of this movement remain less well understood. Here, we report a framework to quantify conformational changes. By analyzing the conformational changes in 234 structures from 45 class A GPCRs, we discovered a common GPCR activation pathway comprising of 34 residue pairs and 35 residues. The pathway unifies previous findings into a common activation mechanism and strings together the scattered key motifs such as CWxP, DRY, Na+ pocket, NPxxY and PIF, thereby directly linking the bottom of ligand-binding pocket with G-protein coupling region. Site-directed mutagenesis experiments support this proposition and reveal that rational mutations of residues in this pathway can be used to obtain receptors that are constitutively active or inactive. The common activation pathway provides the mechanistic interpretation of constitutively activating, inactivating and disease mutations. As a module responsible for activation, the common pathway allows for decoupling of the evolution of the ligand binding site and G-protein-binding region. Such an architecture might have facilitated GPCRs to emerge as a highly successful family of proteins for signal transduction in nature.
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Affiliation(s)
- Qingtong Zhou
- iHuman InstituteShanghaiTech UniversityShanghaiChina
| | - Dehua Yang
- The CAS Key Laboratory of Receptor ResearchShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
- The National Center for Drug ScreeningShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
| | - Meng Wu
- iHuman InstituteShanghaiTech UniversityShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
- School of Life Science and TechnologyShanghaiTech UniversityShanghaiChina
| | - Yu Guo
- iHuman InstituteShanghaiTech UniversityShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
- School of Life Science and TechnologyShanghaiTech UniversityShanghaiChina
| | - Wanjing Guo
- The CAS Key Laboratory of Receptor ResearchShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
- The National Center for Drug ScreeningShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
| | - Li Zhong
- The CAS Key Laboratory of Receptor ResearchShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
- The National Center for Drug ScreeningShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
| | - Xiaoqing Cai
- The CAS Key Laboratory of Receptor ResearchShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
- The National Center for Drug ScreeningShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
| | - Antao Dai
- The CAS Key Laboratory of Receptor ResearchShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
- The National Center for Drug ScreeningShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
| | - Wonjo Jang
- Department of Pharmacology and Toxicology, Medical College of GeorgiaAugusta UniversityAugustaUnited States
| | - Eugene I Shakhnovich
- Department of Chemistry and Chemical BiologyHarvard UniversityCambridgeUnited States
| | - Zhi-Jie Liu
- iHuman InstituteShanghaiTech UniversityShanghaiChina
- School of Life Science and TechnologyShanghaiTech UniversityShanghaiChina
| | - Raymond C Stevens
- iHuman InstituteShanghaiTech UniversityShanghaiChina
- School of Life Science and TechnologyShanghaiTech UniversityShanghaiChina
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of GeorgiaAugusta UniversityAugustaUnited States
| | - M Madan Babu
- MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Ming-Wei Wang
- The CAS Key Laboratory of Receptor ResearchShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
- The National Center for Drug ScreeningShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
- School of Life Science and TechnologyShanghaiTech UniversityShanghaiChina
- School of PharmacyFudan UniversityShanghaiChina
| | - Suwen Zhao
- iHuman InstituteShanghaiTech UniversityShanghaiChina
- School of Life Science and TechnologyShanghaiTech UniversityShanghaiChina
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22
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Wright SC, Kozielewicz P, Kowalski-Jahn M, Petersen J, Bowin CF, Slodkowicz G, Marti-Solano M, Rodríguez D, Hot B, Okashah N, Strakova K, Valnohova J, Babu MM, Lambert NA, Carlsson J, Schulte G. A conserved molecular switch in Class F receptors regulates receptor activation and pathway selection. Nat Commun 2019; 10:667. [PMID: 30737406 PMCID: PMC6368630 DOI: 10.1038/s41467-019-08630-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 01/22/2019] [Indexed: 12/21/2022] Open
Abstract
Class F receptors are considered valuable therapeutic targets due to their role in human disease, but structural changes accompanying receptor activation remain unexplored. Employing population and cancer genomics data, structural analyses, molecular dynamics simulations, resonance energy transfer-based approaches and mutagenesis, we identify a conserved basic amino acid in TM6 in Class F receptors that acts as a molecular switch to mediate receptor activation. Across all tested Class F receptors (FZD4,5,6,7, SMO), mutation of the molecular switch confers an increased potency of agonists by stabilizing an active conformation as assessed by engineered mini G proteins as conformational sensors. Disruption of the switch abrogates the functional interaction between FZDs and the phosphoprotein Dishevelled, supporting conformational selection as a prerequisite for functional selectivity. Our studies reveal the molecular basis of a common activation mechanism conserved in all Class F receptors, which facilitates assay development and future discovery of Class F receptor-targeting drugs. Class F receptors are therapeutic targets in human disease and understanding their structural changes during receptor activation may provide important pharmacological insight. Here, the authors combine computational and experimental methods to identify a molecular switch in TM6/7 of Class F receptors that mediates receptor activation.
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Affiliation(s)
- Shane C Wright
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden
| | - Paweł Kozielewicz
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden
| | - Maria Kowalski-Jahn
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden
| | - Julian Petersen
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden
| | - Carl-Fredrik Bowin
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden
| | - Greg Slodkowicz
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, United Kingdom
| | - Maria Marti-Solano
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, United Kingdom
| | - David Rodríguez
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, P.O. Box 596, SE-751 24, Uppsala, Sweden
| | - Belma Hot
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden
| | - Najeah Okashah
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, Georgia, 30912, USA
| | - Katerina Strakova
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden
| | - Jana Valnohova
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden
| | - M Madan Babu
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, United Kingdom
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, Georgia, 30912, USA
| | - Jens Carlsson
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, P.O. Box 596, SE-751 24, Uppsala, Sweden
| | - Gunnar Schulte
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden.
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23
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Abstract
G protein–coupled receptors (GPCRs) are key signaling proteins that regulate nearly every aspect of cell function. Studies of GPCRs have benefited greatly from the development of molecular tools to monitor receptor activation and downstream signaling. Here, we show that mini G proteins are robust probes that can be used in a variety of assay formats to report GPCR activity in living cells. Mini G (mG) proteins are engineered GTPase domains of Gα subunits that were developed for structural studies of active-state GPCRs. Confocal imaging revealed that mG proteins fused to fluorescent proteins were located diffusely in the cytoplasm and translocated to sites of receptor activation at the cell surface and at intracellular organelles. Bioluminescence resonance energy transfer (BRET) assays with mG proteins fused to either a fluorescent protein or luciferase reported agonist, superagonist, and inverse agonist activities. Variants of mG proteins (mGs, mGsi, mGsq, and mG12) corresponding to the four families of Gα subunits displayed appropriate coupling to their cognate GPCRs, allowing quantitative profiling of subtype-specific coupling to individual receptors. BRET between luciferase–mG fusion proteins and fluorescent markers indicated the presence of active GPCRs at the plasma membrane, Golgi apparatus, and endosomes. Complementation assays with fragments of NanoLuc luciferase fused to GPCRs and mG proteins reported constitutive receptor activity and agonist-induced activation with up to 20-fold increases in luminescence. We conclude that mG proteins are versatile tools for studying GPCR activation and coupling specificity in cells and should be useful for discovering and characterizing G protein subtype–biased ligands.
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Affiliation(s)
- Qingwen Wan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
| | - Najeah Okashah
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578 Japan
| | - Rony Nehmé
- MRC Laboratory of Molecular Biology, Cambridge CB20QH, United Kingdom
| | - Byron Carpenter
- MRC Laboratory of Molecular Biology, Cambridge CB20QH, United Kingdom
| | | | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia 30912.
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24
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Brown NE, Lambert NA, Hepler JR. RGS14 regulates the lifetime of G α-GTP signaling but does not prolong G βγ signaling following receptor activation in live cells. Pharmacol Res Perspect 2016; 4:e00249. [PMID: 27713821 PMCID: PMC5045935 DOI: 10.1002/prp2.249] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 06/28/2016] [Indexed: 12/17/2022] Open
Abstract
RGS14 is a multifunctional scaffolding protein possessing two distinct G protein interaction sites including a regulator of G protein signaling (RGS) domain that acts as a GTPase activating protein (GAP) to deactivate Gαi/o‐GTP proteins, and a G protein regulatory (GPR) motif that binds inactive Gαi1/3‐GDP proteins independent of Gβγ. GPR interactions with Gαi recruit RGS14 to the plasma membrane to interact with Gαi‐linked GPCRs and regulate Gαi signaling. While RGS14 actions on Gα proteins are well characterized, consequent effects on Gβγ signaling remain unknown. Conventional RGS proteins act as dedicated GAPs to deactivate Gα and Gβγ signaling following receptor activation. RGS14 may do the same or, alternatively, may coordinate its actions to deactivate Gα‐GTP with the RGS domain and then capture the same Gα‐GDP via its GPR motif to prevent heterotrimer reassociation and prolong Gβγ signaling. To test this idea, we compared the regulation of G protein activation and deactivation kinetics by a conventional RGS protein, RGS4, and RGS14 in response to GPCR agonist/antagonist treatment utilizing bioluminescence resonance energy transfer (BRET). Co‐expression of either RGS4 or RGS14 inhibited the release of free Gβγ after agonist stimulation and increased the deactivation rate of Gα, consistent with their roles as GTPase activating proteins (GAPs). Overexpression of inactive Gαi1 to recruit RGS14 to the plasma membrane did not alter RGS14′s capacity to act as a GAP for a second Gαo protein. These results demonstrate the role of RGS14 as a dedicated GAP and suggest that the G protein regulatory (GPR) motif functions independently of the RGS domain and is silent in regulating GAP activity in a cellular context.
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Affiliation(s)
- Nicole E Brown
- Department of Pharmacology Emory University School of Medicine Atlanta Georgia 30322
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology Medical College of Georgia at Augusta University Augusta Georgia 30912
| | - John R Hepler
- Department of Pharmacology Emory University School of Medicine Atlanta Georgia 30322
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25
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Abstract
Heterotrimeric G proteins are localized to the plasma membrane where they transduce extracellular signals to intracellular effectors. G proteins also act at intracellular locations, and can translocate between cellular compartments. For example, Gαs can leave the plasma membrane and move to the cell interior after activation. However, the mechanism of Gαs translocation and its intracellular destination are not known. Here we use bioluminescence resonance energy transfer (BRET) to show that after activation, Gαs rapidly associates with the endoplasmic reticulum, mitochondria, and endosomes, consistent with indiscriminate sampling of intracellular membranes from the cytosol rather than transport via a specific vesicular pathway. The primary source of Gαs for endosomal compartments is constitutive endocytosis rather than activity-dependent internalization. Recycling of Gαs to the plasma membrane is complete 25 min after stimulation is discontinued. We also show that an acylation-deacylation cycle is important for the steady-state localization of Gαs at the plasma membrane, but our results do not support a role for deacylation in activity-dependent Gαs internalization.
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Affiliation(s)
- Brent R Martin
- From the Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109 and
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
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26
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Halls ML, Yeatman HR, Nowell CJ, Thompson GL, Gondin AB, Civciristov S, Bunnett NW, Lambert NA, Poole DP, Canals M. Plasma membrane localization of the μ-opioid receptor controls spatiotemporal signaling. Sci Signal 2016; 9:ra16. [PMID: 26861044 DOI: 10.1126/scisignal.aac9177] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Differential regulation of the μ-opioid receptor (MOR), a G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptor, contributes to the clinically limiting effects of opioid analgesics, such as morphine. We used biophysical approaches to quantify spatiotemporal MOR signaling in response to different ligands. In human embryonic kidney (HEK) 293 cells overexpressing MOR, morphine caused a Gβγ-dependent increase in plasma membrane-localized protein kinase C (PKC) activity, which resulted in a restricted distribution of MOR within the plasma membrane and induced sustained cytosolic extracellular signal-regulated kinase (ERK) signaling. In contrast, the synthetic opioid peptide DAMGO ([d-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin) enabled receptor redistribution within the plasma membrane, resulting in transient increases in cytosolic and nuclear ERK activity, and, subsequently, receptor internalization. When Gβγ subunits or PKCα activity was inhibited or when the carboxyl-terminal phosphorylation sites of MOR were mutated, morphine-activated MOR was released from its restricted plasma membrane localization and stimulated a transient increase in cytosolic and nuclear ERK activity in the absence of receptor internalization. Thus, these data suggest that the ligand-induced redistribution of MOR within the plasma membrane, and not its internalization, controls its spatiotemporal signaling.
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Affiliation(s)
- Michelle L Halls
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.
| | - Holly R Yeatman
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Cameron J Nowell
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Georgina L Thompson
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Arisbel Batista Gondin
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Srgjan Civciristov
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Nigel W Bunnett
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia. ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia. Department of Anesthesia and Perioperative Medicine, Monash University, Melbourne, Victoria 3004, Australia. Department of Pharmacology, The University of Melbourne, Parkville, Victoria 3052, Australia
| | - Nevin A Lambert
- Department of Toxicology and Pharmacology, Georgia Regents University, Augusta, GA 30912, USA
| | - Daniel P Poole
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia. Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria 3052, Australia
| | - Meritxell Canals
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia. ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.
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27
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Donthamsetti P, Quejada JR, Javitch JA, Gurevich VV, Lambert NA. Using Bioluminescence Resonance Energy Transfer (BRET) to Characterize Agonist-Induced Arrestin Recruitment to Modified and Unmodified G Protein-Coupled Receptors. ACTA ACUST UNITED AC 2015; 70:2.14.1-2.14.14. [PMID: 26331887 DOI: 10.1002/0471141755.ph0214s70] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
G protein-coupled receptors (GPCRs) represent ∼25% of current drug targets. Ligand binding to these receptors activates G proteins and arrestins, which are involved in differential signaling pathways. Because functionally selective or biased ligands activate one of these two pathways, they may be superior medications for certain diseases states. The identification of such ligands requires robust drug screening assays for both G protein and arrestin activity. This unit describes protocols for two bioluminescence resonance energy transfer (BRET)-based assays used to monitor arrestin recruitment to GPCRs. One assay requires modification of GPCRs by fusion to a BRET donor or acceptor moiety, whereas the other can detect arrestin recruitment to unmodified GPCRs.
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Affiliation(s)
- Prashant Donthamsetti
- Departments of Psychiatry and Pharmacology, Columbia University College of Physicians and Surgeons, New York, New York.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York
| | - Jose Rafael Quejada
- Departments of Psychiatry and Pharmacology, Columbia University College of Physicians and Surgeons, New York, New York.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York
| | - Jonathan A Javitch
- Departments of Psychiatry and Pharmacology, Columbia University College of Physicians and Surgeons, New York, New York.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York
| | | | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia
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28
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Chen Y, Tang H, Seibel W, Papoian R, Li X, Lambert NA, Palczewski K. A High-Throughput Drug Screening Strategy for Detecting Rhodopsin P23H Mutant Rescue and Degradation. Invest Ophthalmol Vis Sci 2015; 56:2553-67. [PMID: 25783607 DOI: 10.1167/iovs.14-16298] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Inherent instability of the P23H mutant opsin accounts for approximately 10% of autosomal dominant retinitis pigmentosa cases. Our purpose was to develop an overall set of reliable screening strategies to assess if either stabilization or enhanced degradation of mutant rhodopsin could rescue rod photoreceptors expressing this mutant protein. These strategies promise to reveal active compounds and clarify molecular mechanisms of biologically important processes, such as inhibition of target degradation or enhanced target folding. METHODS Cell-based bioluminescence reporter assays were developed and validated for high-throughput screening (HTS) of compounds that promote either stabilization or degradation of P23H mutant opsin. Such assays were further complemented by immunoblotting and image-based analyses. RESULTS Two stabilization assays of P23H mutant opsin were developed and validated, one based on β-galactosidase complementarity and a second assay involving bioluminescence resonance energy transfer (BRET) technology. Moreover, two additional assays evaluating mutant protein degradation also were employed, one based on the disappearance of luminescence and another employing the ALPHA immunoassay. Imaging of cells revealed the cellular localization of mutant rhodopsin, whereas immunoblots identified changes in the aggregation and glycosylation of P23H mutant opsin. CONCLUSIONS Our findings indicate that these initial HTS and following assays can identify active therapeutic compounds, even for difficult targets such as mutant rhodopsin. The assays are readily scalable and their function has been proven with model compounds. High-throughput screening, supported by automated imaging and classic immunoassays, can further characterize multiple steps and pathways in the biosynthesis and degradation of this essential visual system protein.
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Affiliation(s)
- Yuanyuan Chen
- Department of Pharmacology Case Western Reserve University, Cleveland, Ohio, United States
| | - Hong Tang
- Drug Discovery Center, College of Medicine, University of Cincinnati, Cincinnati, Ohio, United States
| | - William Seibel
- Drug Discovery Center, College of Medicine, University of Cincinnati, Cincinnati, Ohio, United States
| | - Ruben Papoian
- Drug Discovery Center, College of Medicine, University of Cincinnati, Cincinnati, Ohio, United States
| | - Xiaoyu Li
- Department of Pharmacology Case Western Reserve University, Cleveland, Ohio, United States
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, Georgia, United States
| | - Krzysztof Palczewski
- Department of Pharmacology Case Western Reserve University, Cleveland, Ohio, United States
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29
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Affiliation(s)
- Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, GA, 30912-2300, USA
| | - Jonathan A Javitch
- Departments of Psychiatry and Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, 10032, USA
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30
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Affiliation(s)
- Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, GA, 30912-2300, USA
| | - Jonathan A Javitch
- Departments of Psychiatry and Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, 10032, USA
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31
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Abstract
Live-cell assays based on fluorescence and luminescence are now indispensable tools for the study of G protein signaling. Assays based on fluorescence and bioluminescence resonance energy transfer (FRET and BRET) have been particularly valuable for monitoring changes in second messengers, protein-protein interactions, and protein conformation. Here, we describe a BRET assay that monitors the release of free Gβγ dimers after activation of heterotrimers containing Gα subunits from all four G protein subfamilies. This assay provides useful kinetic and pharmacological information with reasonably high throughput using a standard laboratory equipment.
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Affiliation(s)
- Ikuo Masuho
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL, 33458, USA
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32
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Clayton CC, Donthamsetti P, Lambert NA, Javitch JA, Neve KA. Mutation of three residues in the third intracellular loop of the dopamine D2 receptor creates an internalization-defective receptor. J Biol Chem 2014; 289:33663-75. [PMID: 25336643 DOI: 10.1074/jbc.m114.605378] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Arrestins mediate desensitization and internalization of G protein-coupled receptors and also direct receptor signaling toward heterotrimeric G protein-independent signaling pathways. We previously identified a four-residue segment (residues 212-215) of the dopamine D2 receptor that is necessary for arrestin binding in an in vitro heterologous expression system but that also impairs receptor expression. We now describe the characterization of additional mutations at that arrestin binding site in the third intracellular loop. Mutating two (residues 214 and 215) or three (residues 213-215) of the four residues to alanine partially decreased agonist-induced recruitment of arrestin3 without altering activation of a G protein. Arrestin-dependent receptor internalization, which requires arrestin binding to β2-adaptin (the β2 subunit of the clathrin-associated adaptor protein AP2) and clathrin, was disproportionately affected by the three-residue mutation, with no agonist-induced internalization observed even in the presence of overexpressed arrestin or G protein-coupled receptor kinase 2. The disjunction between arrestin recruitment and internalization could not be explained by alterations in the time course of the receptor-arrestin interaction, the recruitment of G protein-coupled receptor kinase 2, or the receptor-induced interaction between arrestin and β2-adaptin, suggesting that the mutation impairs a property of the internalization complex that has not yet been identified.
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Affiliation(s)
- Cecilea C Clayton
- the Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon 97239
| | - Prashant Donthamsetti
- the Departments of Psychiatry and Pharmacology, Columbia University College of Physicians and Surgeons, New York, New York 10032, the Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York 10032, and
| | - Nevin A Lambert
- the Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia 30912
| | - Jonathan A Javitch
- the Departments of Psychiatry and Pharmacology, Columbia University College of Physicians and Surgeons, New York, New York 10032, the Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York 10032, and
| | - Kim A Neve
- the Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon 97239, From the Research Service, Department of Veterans Affairs Medical Center, Portland, Oregon 97239,
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Jin C, Sun J, Stilphen CA, Smith SME, Ocasio H, Bermingham B, Darji S, Guha A, Patel R, Geurts AM, Jacob HJ, Lambert NA, O'Connor PM. HV1 acts as a sodium sensor and promotes superoxide production in medullary thick ascending limb of Dahl salt-sensitive rats. Hypertension 2014; 64:541-50. [PMID: 24935944 DOI: 10.1161/hypertensionaha.114.03549] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We previously characterized a H(+) transport pathway in medullary thick ascending limb nephron segments that when activated stimulated the production of superoxide by nicotinamide adenine dinucleotide phosphate oxidase. Importantly, the activity of this pathway was greater in Dahl salt-sensitive rats than salt-resistant (SS.13(BN)) rats, and superoxide production was enhanced in low Na(+) media. The goal of this study was to determine the molecular identity of this pathway and its relationship to Na(+). We hypothesized that the voltage-gated proton channel, HV1, was the source of superoxide-stimulating H(+) currents. To test this hypothesis, we developed HV1(-/-) null mutant rats on the Dahl salt-sensitive rat genetic background using zinc-finger nuclease gene targeting. HV1 could be detected in medullary thick limb from wild-type rats. Intracellular acidification using an NH4Cl prepulse in 0 sodium/BaCl2 containing media resulted in superoxide production in thick limb from wild-type but not HV1(-/-) rats (P<0.05) and more rapid recovery of intracellular pH in wild-type rats (ΔpHI 0.005 versus 0.002 U/s, P=0.046, respectively). Superoxide production was enhanced by low intracellular sodium (<10 mmol/L) in both thick limb and peritoneal macrophages only when HV1 was present. When fed a high-salt diet, blood pressure, outer medullary renal injury (tubular casts), and oxidative stress (4-hydroxynonenal staining) were significantly reduced in HV1(-/-) rats compared with wild-type Dahl salt-sensitive rats. We conclude that HV1 is expressed in medullary thick ascending limb and promotes superoxide production in this segment when intracellular Na(+) is low. HV1 contributes to the development of hypertension and renal disease in Dahl salt-sensitive rats.
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Affiliation(s)
- Chunhua Jin
- From the Department of Physiology (C.J, J.S., C.A.S., H.O., B.B., S.D., A.G., R.P., P.M.O.) and Department of Pharmacology and Toxicology (N.A.L.), Georgia Regents University, Augusta; Department of Physiology, Medical College of Wisconsin, Milwaukee (A.M.G., H.J.J.); and Department of Biology & Physics, Kennesaw State University, Atlanta, GA (S.M.E.S.)
| | - Jingping Sun
- From the Department of Physiology (C.J, J.S., C.A.S., H.O., B.B., S.D., A.G., R.P., P.M.O.) and Department of Pharmacology and Toxicology (N.A.L.), Georgia Regents University, Augusta; Department of Physiology, Medical College of Wisconsin, Milwaukee (A.M.G., H.J.J.); and Department of Biology & Physics, Kennesaw State University, Atlanta, GA (S.M.E.S.)
| | - Carly A Stilphen
- From the Department of Physiology (C.J, J.S., C.A.S., H.O., B.B., S.D., A.G., R.P., P.M.O.) and Department of Pharmacology and Toxicology (N.A.L.), Georgia Regents University, Augusta; Department of Physiology, Medical College of Wisconsin, Milwaukee (A.M.G., H.J.J.); and Department of Biology & Physics, Kennesaw State University, Atlanta, GA (S.M.E.S.)
| | - Susan M E Smith
- From the Department of Physiology (C.J, J.S., C.A.S., H.O., B.B., S.D., A.G., R.P., P.M.O.) and Department of Pharmacology and Toxicology (N.A.L.), Georgia Regents University, Augusta; Department of Physiology, Medical College of Wisconsin, Milwaukee (A.M.G., H.J.J.); and Department of Biology & Physics, Kennesaw State University, Atlanta, GA (S.M.E.S.)
| | - Hiram Ocasio
- From the Department of Physiology (C.J, J.S., C.A.S., H.O., B.B., S.D., A.G., R.P., P.M.O.) and Department of Pharmacology and Toxicology (N.A.L.), Georgia Regents University, Augusta; Department of Physiology, Medical College of Wisconsin, Milwaukee (A.M.G., H.J.J.); and Department of Biology & Physics, Kennesaw State University, Atlanta, GA (S.M.E.S.)
| | - Brent Bermingham
- From the Department of Physiology (C.J, J.S., C.A.S., H.O., B.B., S.D., A.G., R.P., P.M.O.) and Department of Pharmacology and Toxicology (N.A.L.), Georgia Regents University, Augusta; Department of Physiology, Medical College of Wisconsin, Milwaukee (A.M.G., H.J.J.); and Department of Biology & Physics, Kennesaw State University, Atlanta, GA (S.M.E.S.)
| | - Sandip Darji
- From the Department of Physiology (C.J, J.S., C.A.S., H.O., B.B., S.D., A.G., R.P., P.M.O.) and Department of Pharmacology and Toxicology (N.A.L.), Georgia Regents University, Augusta; Department of Physiology, Medical College of Wisconsin, Milwaukee (A.M.G., H.J.J.); and Department of Biology & Physics, Kennesaw State University, Atlanta, GA (S.M.E.S.)
| | - Avirup Guha
- From the Department of Physiology (C.J, J.S., C.A.S., H.O., B.B., S.D., A.G., R.P., P.M.O.) and Department of Pharmacology and Toxicology (N.A.L.), Georgia Regents University, Augusta; Department of Physiology, Medical College of Wisconsin, Milwaukee (A.M.G., H.J.J.); and Department of Biology & Physics, Kennesaw State University, Atlanta, GA (S.M.E.S.)
| | - Roshan Patel
- From the Department of Physiology (C.J, J.S., C.A.S., H.O., B.B., S.D., A.G., R.P., P.M.O.) and Department of Pharmacology and Toxicology (N.A.L.), Georgia Regents University, Augusta; Department of Physiology, Medical College of Wisconsin, Milwaukee (A.M.G., H.J.J.); and Department of Biology & Physics, Kennesaw State University, Atlanta, GA (S.M.E.S.)
| | - Aron M Geurts
- From the Department of Physiology (C.J, J.S., C.A.S., H.O., B.B., S.D., A.G., R.P., P.M.O.) and Department of Pharmacology and Toxicology (N.A.L.), Georgia Regents University, Augusta; Department of Physiology, Medical College of Wisconsin, Milwaukee (A.M.G., H.J.J.); and Department of Biology & Physics, Kennesaw State University, Atlanta, GA (S.M.E.S.)
| | - Howard J Jacob
- From the Department of Physiology (C.J, J.S., C.A.S., H.O., B.B., S.D., A.G., R.P., P.M.O.) and Department of Pharmacology and Toxicology (N.A.L.), Georgia Regents University, Augusta; Department of Physiology, Medical College of Wisconsin, Milwaukee (A.M.G., H.J.J.); and Department of Biology & Physics, Kennesaw State University, Atlanta, GA (S.M.E.S.)
| | - Nevin A Lambert
- From the Department of Physiology (C.J, J.S., C.A.S., H.O., B.B., S.D., A.G., R.P., P.M.O.) and Department of Pharmacology and Toxicology (N.A.L.), Georgia Regents University, Augusta; Department of Physiology, Medical College of Wisconsin, Milwaukee (A.M.G., H.J.J.); and Department of Biology & Physics, Kennesaw State University, Atlanta, GA (S.M.E.S.)
| | - Paul M O'Connor
- From the Department of Physiology (C.J, J.S., C.A.S., H.O., B.B., S.D., A.G., R.P., P.M.O.) and Department of Pharmacology and Toxicology (N.A.L.), Georgia Regents University, Augusta; Department of Physiology, Medical College of Wisconsin, Milwaukee (A.M.G., H.J.J.); and Department of Biology & Physics, Kennesaw State University, Atlanta, GA (S.M.E.S.).
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Yeatman HR, Lane JR, Choy KHC, Lambert NA, Sexton PM, Christopoulos A, Canals M. Allosteric modulation of M1 muscarinic acetylcholine receptor internalization and subcellular trafficking. J Biol Chem 2014; 289:15856-66. [PMID: 24753247 DOI: 10.1074/jbc.m113.536672] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Allosteric modulators are an attractive approach to achieve receptor subtype-selective targeting of G protein-coupled receptors. Benzyl quinolone carboxylic acid (BQCA) is an unprecedented example of a highly selective positive allosteric modulator of the M1 muscarinic acetylcholine receptor (mAChR). However, despite favorable pharmacological characteristics of BQCA in vitro and in vivo, there is limited evidence of the impact of allosteric modulation on receptor regulatory mechanisms such as β-arrestin recruitment or receptor internalization and endocytic trafficking. In the present study we investigated the impact of BQCA on M1 mAChR regulation. We show that BQCA potentiates agonist-induced β-arrestin recruitment to M1 mAChRs. Using a bioluminescence resonance energy transfer approach to monitor intracellular trafficking of M1 mAChRs, we show that once internalized, M1 mAChRs traffic to early endosomes, recycling endosomes and late endosomes. We also show that BQCA potentiates agonist-induced subcellular trafficking. M1 mAChR internalization is both β-arrestin and G protein-dependent, with the third intracellular loop playing an important role in the dynamics of β-arrestin recruitment. As the global effect of receptor activation ultimately depends on the levels of receptor expression at the cell surface, these results illustrate the need to extend the characterization of novel allosteric modulators of G protein-coupled receptors to encapsulate the consequences of chronic exposure to this family of ligands.
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Affiliation(s)
- Holly R Yeatman
- From the Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Melbourne, Victoria 3052, Australia and
| | - J Robert Lane
- From the Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Melbourne, Victoria 3052, Australia and
| | - Kwok Ho Christopher Choy
- From the Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Melbourne, Victoria 3052, Australia and
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, Georgia 30912
| | - Patrick M Sexton
- From the Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Melbourne, Victoria 3052, Australia and
| | - Arthur Christopoulos
- From the Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Melbourne, Victoria 3052, Australia and
| | - Meritxell Canals
- From the Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Melbourne, Victoria 3052, Australia and
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Promsote W, Veeranan-Karmegam R, Ananth S, Shen D, Chan CC, Lambert NA, Ganapathy V, Martin PM. L-2-oxothiazolidine-4-carboxylic acid attenuates oxidative stress and inflammation in retinal pigment epithelium. Mol Vis 2014; 20:73-88. [PMID: 24426777 PMCID: PMC3888500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 01/03/2014] [Indexed: 11/21/2022] Open
Abstract
PURPOSE Oxidant- and inflammation-induced damage to retinal pigment epithelial (RPE) cells is central to the pathogenesis of age-related macular degeneration (AMD). Thus, developing novel strategies to protect these cells is important. We reported previously on the robust antioxidant and therefore cell-protective effects of the cysteine pro-drug L-2-oxothiazolidine-4-carboxylic acid (OTC) in cultured human RPE cells. New reports citing a novel anti-inflammatory role for OTC in addition to the known glutathione-stimulating and antioxidant properties emerged recently; however, this role has not been evaluated in RPE cells or in intact retina. Given the crucial causative roles of oxidative stress and inflammation in AMD pathogenesis, knowing whether OTC might exhibit a similar benefit in this cell and tissue type has high clinical relevance; thus, we evaluated OTC in the present study. METHODS ARPE-19 and primary RPE cells isolated from wild-type, Gpr109a(-/-) , or Slc5a8(-/-) mouse eyes were exposed to TNF-α in the presence or absence of OTC, followed by analysis of IL-6 and Ccl2 expression with real-time quantitative polymerase chain reaction or enzyme-linked immunosorbent assay. Cellular and molecular markers of inflammation and oxidative stress (i.e., IL-1β, TGF-β, ABCG1, ABCA1, reduced glutathione, and dihydroethidium) were evaluated in Ccl2(-/-)/Cx3cr1(-/-) double knockout mice on rd8 background (DKO rd8) treated with OTC (10 mg/ml) in drinking water for a period of 5 months. RESULTS OTC treatment significantly inhibited the expression and secretion of IL-6 and Ccl2 in TNF-α-stimulated ARPE-19 cells. Studies conducted using DKO rd8 animals treated with OTC in drinking water confirmed these findings. Cellular and molecular markers of inflammation were significantly suppressed in the retinas of the OTC-treated DKO rd8 animals. Subsequent in vitro and in vivo studies of the possible mechanism(s) to explain these actions revealed that although OTC is an agonist of the anti-inflammatory G-protein coupled receptor GPR109A and a transportable substrate of the sodium-coupled monocarboxylate transporter SMCT1 (SLC5A8), these properties may play a role but do not explain entirely the anti-inflammatory effects this compound elicits in cultured RPE cells and the intact mouse retina. CONCLUSIONS This study represents, to our knowledge, the first report of the suppressive effects of OTC on inflammation in cultured RPE cells and on inflammation and oxidative stress in the retina in vivo.
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Affiliation(s)
- Wanwisa Promsote
- Department of Biochemistry and Molecular Biology, Georgia Regents University, Augusta, GA
| | | | - Sudha Ananth
- Department of Biochemistry and Molecular Biology, Georgia Regents University, Augusta, GA
| | - Defen Shen
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Chi-Chao Chan
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Nevin A. Lambert
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA
| | - Vadivel Ganapathy
- Department of Biochemistry and Molecular Biology, Georgia Regents University, Augusta, GA,James and Jean Culver Vision Discovery Institute, Georgia Regents University, Augusta, GA
| | - Pamela M. Martin
- Department of Biochemistry and Molecular Biology, Georgia Regents University, Augusta, GA,Department of Ophthalmology, and the Georgia Regents University, Augusta, GA,James and Jean Culver Vision Discovery Institute, Georgia Regents University, Augusta, GA
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Jensen DD, Godfrey CB, Niklas C, Canals M, Kocan M, Poole DP, Murphy JE, Alemi F, Cottrell GS, Korbmacher C, Lambert NA, Bunnett NW, Corvera CU. The bile acid receptor TGR5 does not interact with β-arrestins or traffic to endosomes but transmits sustained signals from plasma membrane rafts. J Biol Chem 2013; 288:22942-60. [PMID: 23818521 DOI: 10.1074/jbc.m113.455774] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
TGR5 is a G protein-coupled receptor that mediates bile acid (BA) effects on energy balance, inflammation, digestion, and sensation. The mechanisms and spatiotemporal control of TGR5 signaling are poorly understood. We investigated TGR5 signaling and trafficking in transfected HEK293 cells and colonocytes (NCM460) that endogenously express TGR5. BAs (deoxycholic acid (DCA), taurolithocholic acid) and the selective agonists oleanolic acid and 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N, 5-dimethylisoxazole-4-carboxamide stimulated cAMP formation but did not induce TGR5 endocytosis or recruitment of β-arrestins, as assessed by confocal microscopy. DCA, taurolithocholic acid, and oleanolic acid did not stimulate TGR5 association with β-arrestin 1/2 or G protein-coupled receptor kinase (GRK) 2/5/6, as determined by bioluminescence resonance energy transfer. 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N, 5-dimethylisoxazole-4-carboxamide stimulated a low level of TGR5 interaction with β-arrestin 2 and GRK2. DCA induced cAMP formation at the plasma membrane and cytosol, as determined using exchange factor directly regulated by cAMP (Epac2)-based reporters, but cAMP signals did not desensitize. AG1478, an inhibitor of epidermal growth factor receptor tyrosine kinase, the metalloprotease inhibitor batimastat, and methyl-β-cyclodextrin and filipin, which block lipid raft formation, prevented DCA stimulation of ERK1/2. Bioluminescence resonance energy transfer analysis revealed TGR5 and EGFR interactions that were blocked by disruption of lipid rafts. DCA stimulated TGR5 redistribution to plasma membrane microdomains, as localized by immunogold electron microscopy. Thus, TGR5 does not interact with β-arrestins, desensitize, or traffic to endosomes. TGR5 signals from plasma membrane rafts that facilitate EGFR interaction and transactivation. An understanding of the spatiotemporal control of TGR5 signaling provides insights into the actions of BAs and therapeutic TGR5 agonists/antagonists.
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Affiliation(s)
- Dane D Jensen
- Monash Institute of Pharmaceutical Sciences, 381 Royal Parade, Parkville, Victoria 3052, Australia
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Gavalas A, Lan TH, Liu Q, Corrêa IR, Javitch JA, Lambert NA. Segregation of family A G protein-coupled receptor protomers in the plasma membrane. Mol Pharmacol 2013; 84:346-52. [PMID: 23778362 DOI: 10.1124/mol.113.086868] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
G protein-coupled receptors (GPCRs) transduce many important physiological signals and are targets for a large fraction of therapeutic drugs. Members of the largest family of GPCRs (family A) are thought to self-associate as dimers and higher-order oligomers, although the significance of such quaternary structures for signaling or receptor trafficking is known for only a few examples. One outstanding question is the physical stability of family A oligomers in cell membranes. Stable oligomers would be expected to move through cellular compartments and membrane domains as intact groups of protomers. Here, we test this prediction by recruiting subsets of affinity-tagged family A protomers into artificial microdomains on the surface of living cells and asking if untagged protomers move into these domains (are corecruited) at the same time. We find that tagged β₂ adrenergic and μ-opioid protomers are unable to corecruit untagged protomers into microdomains. In contrast, tagged metabotropic glutamate receptor protomers do corecruit untagged protomers into such microdomains, which is consistent with the known covalent mechanism whereby these family C receptors dimerize. These observations suggest that interactions between these family A protomers are too weak to directly influence subcellular location, and that mechanisms that move these receptors between subcellular compartments and domains must operate on individual protomers.
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Affiliation(s)
- Anthony Gavalas
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia 30912-2300, USA
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Lan TH, Lambert NA. Diffusion-Enhanced FRET between Membrane Proteins. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.3763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Abstract
The molecular mechanisms underlying the transport from the Golgi to the cell surface of G protein-coupled receptors remain poorly elucidated. Here we determined the role of Rab26, a Ras-like small GTPase involved in vesicle-mediated secretion, in the cell surface export of α(2)-adrenergic receptors. We found that transient expression of Rab26 mutants and siRNA-mediated depletion of Rab26 significantly attenuated the cell surface numbers of α(2A)-AR and α(2B)-AR, as well as ERK1/2 activation by α(2B)-AR. Furthermore, the receptors were extensively arrested in the Golgi by Rab26 mutants and siRNA. Moreover, Rab26 directly and activation-dependently interacted with α(2B)-AR, specifically the third intracellular loop. These data demonstrate that the small GTPase Rab26 regulates the Golgi to cell surface traffic of α(2)-adrenergic receptors, likely through a physical interaction. These data also provide the first evidence implicating an important function of Rab26 in coordinating plasma membrane protein transport.
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Affiliation(s)
- Chunman Li
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, Georgia 30912, USA
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Lan TH, Liu Q, Li C, Wu G, Lambert NA. Sensitive and high resolution localization and tracking of membrane proteins in live cells with BRET. Traffic 2012; 13:1450-6. [PMID: 22816793 DOI: 10.1111/j.1600-0854.2012.01401.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 07/17/2012] [Accepted: 07/20/2012] [Indexed: 11/30/2022]
Abstract
Peripheral and integral membrane proteins can be located in several different subcellular compartments, and it is often necessary to determine the location of such proteins or to track their movement in living cells. Image-based colocalization of labeled membrane proteins and compartment markers is frequently used for this purpose, but this method is limited in terms of throughput and resolution. Here we show that bioluminescence resonance energy transfer (BRET) between membrane proteins of interest and compartment-targeted BRET partners can report subcellular location and movement of membrane proteins in live cells. The sensitivity of the method is sufficient to localize a few hundred protein copies per cell. The spatial resolution can be sufficient to determine membrane topology, and the temporal resolution is sufficient to track changes that occur in less than 1 second. BRET requires little user intervention, and is thus amenable to large-scale experimental designs with standard instruments.
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Affiliation(s)
- Tien-Hung Lan
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, GA 30809, USA
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Dong C, Nichols CD, Guo J, Huang W, Lambert NA, Wu G. A triple arg motif mediates α(2B)-adrenergic receptor interaction with Sec24C/D and export. Traffic 2012; 13:857-68. [PMID: 22404651 DOI: 10.1111/j.1600-0854.2012.01351.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 03/07/2012] [Accepted: 03/09/2012] [Indexed: 12/28/2022]
Abstract
Recent studies have demonstrated that cargo exit from the endoplasmic reticulum (ER) may be directed by ER export motifs recognized by components of the coat protein II (COPII) vesicles. However, little is known about ER export motifs and vesicle targeting of the G protein-coupled receptor (GPCR) superfamily. Here, we have demonstrated that a triple Arg (3R) motif in the third intracellular loop functions as a novel ER export signal for α(2B)-adrenergic receptor (α(2B)-AR). The 3R motif mediates α(2B)-AR interaction with Sec24C/D and modulates ER exit, cell surface transport and function of α(2B)-AR. Furthermore, export function of the 3R motif is independent of its position within α(2B)-AR and can be conferred to CD8 glycoprotein. These data provide the first evidence implicating that export of GPCRs is controlled by code-directed interactions with selective components of the COPII transport machinery.
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Affiliation(s)
- Chunmin Dong
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, 1901 Perdido St, New Orleans, LA 70112, USA
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Qin K, Dong C, Wu G, Lambert NA. Inactive-state preassembly of G(q)-coupled receptors and G(q) heterotrimers. Nat Chem Biol 2011; 7:740-7. [PMID: 21873996 PMCID: PMC3177959 DOI: 10.1038/nchembio.642] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 06/29/2011] [Indexed: 12/29/2022]
Abstract
G protein-coupled receptors (GPCRs) transmit signals by forming active-state complexes with heterotrimeric G proteins. It has been suggested that some GPCRs also assemble with G proteins before ligand-induced activation and that inactive-state preassembly facilitates rapid and specific G protein activation. However, no mechanism of preassembly has been described, and no functional consequences of preassembly have been demonstrated. Here we show that M(3) muscarinic acetylcholine receptors (M3R) form inactive-state complexes with G(q) heterotrimers in intact cells. The M3R C terminus is sufficient, and a six-amino-acid polybasic sequence distal to helix 8 ((565)KKKRRK(570)) is necessary for preassembly with G(q). Replacing this sequence with six alanine residues prevents preassembly, slows the rate of G(q) activation and decreases steady-state agonist sensitivity. That other G(q)-coupled receptors possess similar polybasic regions and also preassemble with G(q) suggests that these GPCRs may use a common preassembly mechanism to facilitate activation of G(q) heterotrimers.
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Affiliation(s)
- Kou Qin
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, Georgia, USA
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Middlemore-Risher ML, Adam BL, Lambert NA, Terry AV. Effects of chlorpyrifos and chlorpyrifos-oxon on the dynamics and movement of mitochondria in rat cortical neurons. J Pharmacol Exp Ther 2011; 339:341-9. [PMID: 21799050 DOI: 10.1124/jpet.111.184762] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Organophosphate (OP)-based pesticides have been used extensively for decades, and as a result, they have become almost ubiquitous in our environment. There is clinical and animal evidence to suggest that chronic exposures to OPs can lead to cognitive dysfunction and other neurological abnormalities, although the mechanism for these effects is unknown. We previously reported that repeated, subthreshold exposures (defined as doses not associated with signs of acute toxicity) to the commonly used OP chlorpyrifos (CPF) resulted in protracted impairments in the performance of attention and memory-related tasks in rodents as well as deficits in axonal transport ex vivo (in the sciatic nerve). Here, we investigated the effects of CPF and its active metabolite CPF oxon (CPO) on the dynamics and movement of mitochondria in rat primary cortical neurons using time-lapse imaging techniques. Exposure to CPF (1.0-20.0 μM) or CPO (5.0 nM-20.0 μM) for 1 or 24 h resulted in a concentration-dependent increase in mitochondrial length, a decrease in mitochondrial number (indicative of increased fusion events), and a decrease in their movement in axons. The changes occurred at concentrations of CPF and CPO that did not inhibit acetylcholinesterase activity (the commonly cited mechanism of acute OP toxicity), and they were not blocked by cholinergic receptor antagonists. Furthermore, the changes did not seem to be associated with direct (OP-related) effects on mitochondrial viability or function (i.e., mitochondrial membrane potential or ATP production). The results suggest that an underlying mechanism of organophosphate-based deficits in cognitive function might involve alterations in mitochondrial dynamics and/or their transport in axons.
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Affiliation(s)
- Mary-Louise Middlemore-Risher
- Program in Clinical and Experimental Therapeutics, University of Georgia, College of Pharmacy, Augusta, Georgia 30912-2450, USA
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Abstract
G protein-coupled receptors (GPCRs) self-associate as dimers or higher-order oligomers in living cells. The stability of associated GPCRs has not been extensively studied, but it is generally thought that these receptors move between the plasma membrane and intracellular compartments as intact dimers or oligomers. Here we show that β(2)-adrenergic receptors (β(2)ARs) that self-associate at the plasma membrane can dissociate during agonist-induced internalization. We use bioluminescence-resonance energy transfer (BRET) to monitor movement of β(2)ARs between subcellular compartments. BRET between β(2)ARs and plasma membrane markers decreases in response to agonist activation, while at the same time BRET between β(2)ARs and endosome markers increases. Energy transfer between β(2)ARs is decreased in a similar manner if either the donor- or acceptor-labeled receptor is mutated to impair agonist binding and internalization. These changes take place over the course of 30 minutes, persist after agonist is removed, and are sensitive to several inhibitors of arrestin- and clathrin-mediated endocytosis. The magnitude of the decrease in BRET between donor- and acceptor-labeled β(2)ARs suggests that at least half of the receptors that contribute to the BRET signal are physically segregated by internalization. These results are consistent with the possibility that β(2)ARs associate transiently with each other in the plasma membrane, or that β(2)AR dimers or oligomers are actively disrupted during internalization.
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Affiliation(s)
- Tien-Hung Lan
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Sudhakiranmayi Kuravi
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Nevin A. Lambert
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, Georgia, United States of America
- * E-mail:
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Johnston JM, Aburi M, Provasi D, Bortolato A, Urizar E, Lambert NA, Javitch JA, Filizola M. Making structural sense of dimerization interfaces of delta opioid receptor homodimers. Biochemistry 2011; 50:1682-90. [PMID: 21261298 PMCID: PMC3050604 DOI: 10.1021/bi101474v] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
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Opioid receptors, like other members of the G protein-coupled receptor (GPCR) family, have been shown to associate to form dimers and/or oligomers at the plasma membrane. Whether this association is stable or transient is not known. Recent compelling evidence suggests that at least some GPCRs rapidly associate and dissociate. We have recently calculated binding affinities from free energy estimates to predict transient association between mouse delta opioid receptor (DOR) protomers at a symmetric interface involving the fourth transmembrane (TM4) helix (herein termed “4” dimer). Here we present disulfide cross-linking experiments with DOR constructs with cysteines substituted at the extracellular ends of TM4 or TM5 that confirm the formation of DOR complexes involving these helices. Our results are consistent with the involvement of TM4 and/or TM5 at the DOR homodimer interface, but possibly with differing association propensities. Coarse-grained (CG) well-tempered metadynamics simulations of two different dimeric arrangements of DOR involving TM4 alone or with TM5 (herein termed “4/5” dimer) in an explicit lipid−water environment confirmed the presence of two structurally and energetically similar configurations of the 4 dimer, as previously assessed by umbrella sampling calculations, and revealed a single energetic minimum of the 4/5 dimer. Additional CG umbrella sampling simulations of the 4/5 dimer indicated that the strength of association between DOR protomers varies depending on the protein region at the interface, with the 4 dimer being more stable than the 4/5 dimer.
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Affiliation(s)
- Jennifer M Johnston
- Department of Structural and Chemical Biology, Mount Sinai School of Medicine, New York, New York 10029, United States
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Kuravi S, Lan TH, Barik A, Lambert NA. Third-party bioluminescence resonance energy transfer indicates constitutive association of membrane proteins: application to class a g-protein-coupled receptors and g-proteins. Biophys J 2010; 98:2391-9. [PMID: 20483349 DOI: 10.1016/j.bpj.2010.02.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 02/01/2010] [Accepted: 02/03/2010] [Indexed: 10/19/2022] Open
Abstract
Many of the molecules that mediate G-protein signaling are thought to constitutively associate with each other in variably stable signaling complexes. Much of the evidence for signaling complexes has come from Förster resonance energy transfer and bioluminescence resonance energy transfer (BRET) studies. However, detection of constitutive protein association with these methods is hampered by nonspecific energy transfer that occurs when donor and acceptor molecules are in close proximity by chance. We show that chemically-induced recruitment of local third-party BRET donors or acceptors reliably separates nonspecific and specific BRET. We use this method to reexamine the constitutive association of class A G-protein-coupled receptors (GPCRs) with other GPCRs and with heterotrimeric G-proteins. We find that beta2 adrenoreceptors constitutively associate with each other and with several other class A GPCRs. In contrast, GPCRs and G-proteins are unlikely to exist in stable constitutive preassembled complexes.
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Affiliation(s)
- Sudhakiranmayi Kuravi
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta, Georgia, USA
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Singh N, Thangaraju M, Prasad PD, Martin PM, Lambert NA, Boettger T, Offermanns S, Ganapathy V. Blockade of dendritic cell development by bacterial fermentation products butyrate and propionate through a transporter (Slc5a8)-dependent inhibition of histone deacetylases. J Biol Chem 2010; 285:27601-8. [PMID: 20601425 DOI: 10.1074/jbc.m110.102947] [Citation(s) in RCA: 192] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Mammalian colon harbors trillions of bacteria, yet there is no undue inflammatory response by the host against these bacteria under normal conditions. The bacterial fermentation products acetate, propionate, and butyrate are believed, at least in part, to be responsible for these immunosuppressive effects. Dendritic cells play an essential role in presentation of antigens to T lymphocytes and initiation of adaptive immune responses. Here we report that butyrate and propionate block the generation of dendritic cells from bone marrow stem cells, without affecting the generation of granulocytes. This effect is dependent on the Na(+)-coupled monocarboxylate transporter Slc5a8, which transports butyrate and propionate into cells, and on the ability of these two bacterial metabolites to inhibit histone deacetylases. Acetate, which is also a substrate for Slc5a8 but not an inhibitor of histone deacetylases, does not affect dendritic cell development, indicating the essential role of histone deacetylase inhibition in the process. The blockade of dendritic cell development by butyrate and propionate is associated with decreased expression of the transcription factors PU.1 and RelB. Butyrate also elicits its biologic effects through its ability to activate the G-protein-coupled receptor Gpr109a, but this mechanism is not involved in butyrate-induced blockade of dendritic cell development. The participation of Slc5a8 and the non-involvement of Gpr109a in butyrate effects have been substantiated using bone marrow cells obtained from Slc5a8(-/-) and Gpr109a(-/-) mice. These findings uncover an important mechanism underlying the anti-inflammatory functions of the bacterial fermentation products butyrate and propionate.
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Affiliation(s)
- Nagendra Singh
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, Georgia 30912, USA
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Abstract
G protein-coupled receptors (GPCRs), also known as seven-transmembrane receptors (7TMRs), transduce various sensory and nonsensory signals. It is now widely accepted that these receptors associate with each other as homomeric or heteromeric dimers or as higher-order oligomers. This realization raises a number of questions regarding the quaternary structure of GPCRs and the function of GPCR oligomers: How does ligand binding in one protomer affect an associated protomer? What is the functional unit that activates downstream signaling molecules? What parts of the receptor form the interfaces between protomers? Where along the pathway from synthesis to degradation do oligomers form? Do they ever dissociate? Until recently, this last question has attracted little attention, and GPCR dimers and oligomers have generally been considered to be stable structures. However, biophysical studies have now begun to address this question, and the answer that is emerging will require a reassessment of the stable dimer model.
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Affiliation(s)
- Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta, GA 30912-2300, USA.
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Abstract
GPR6 is a constitutively active Gs-coupled receptor that can signal from intracellular compartments. We present different methods used to study cell surface expression of receptors and other membrane proteins. A comparison of these methods shows that methods based on susceptibility to proteolytic enzymes are more efficient at providing estimates of cell surface expression than the commonly used cell surface biotinylation method. We also present different methods that can be used to detect constitutive activity of Gs-coupled receptors. Imaging-based assays to detect intracellular cyclic AMP accumulation are well suited to study signaling at a single cell level. These assays are particularly useful when the cells of interest form a small fraction of the culture such as primary cultures with low transfection efficiency.
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Affiliation(s)
- Balakrishna M Prasad
- Department of Clinical Investigation, Eisenhower Army Medical Center, Georgia, USA
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