1
|
Gao M, Dekker ME, Leurs R, Vischer HF. Pharmacological characterization of seven human histamine H 3 receptor isoforms. Eur J Pharmacol 2024; 968:176450. [PMID: 38387718 DOI: 10.1016/j.ejphar.2024.176450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/29/2024] [Accepted: 02/20/2024] [Indexed: 02/24/2024]
Abstract
The histamine H3 receptor (H3R) regulates as a presynaptic G protein-coupled receptor the release of histamine and other neurotransmitters in the brain, and is consequently a potential therapeutic target for neuronal disorders. The human H3R encodes for seven splice variants that vary in the length of intracellular loop 3 and/or the C-terminal tail but are all able to induce heterotrimeric Gi protein signaling. The last two decades H3R drug discovery and lead optimization has been exclusively focused on the 445 amino acids-long reference isoform H3R-445. In this study, we pharmacologically characterized for the first time all seven H3R isoforms by determining their binding affinities for reference histamine H3 receptor agonists and inverse agonists. The H3R-453, H3R-415, and H3R-413 isoforms display similar binding affinities for all ligands as the H3R-445. However, increased agonist binding affinities were observed for the three shorter isoforms H3R-329, H3R-365, and H3R-373, whereas inverse agonists such as the approved anti-narcolepsy drug pitolisant (Wakix®) displayed significantly decreased binding affinities for the latter two isoforms. This opposite change in binding affinity of agonist versus inverse agonists on H3R-365 and H3R-373 is associated with their higher constitutive activity in a cAMP biosensor assay as compared to the other five isoforms. The observed differences in pharmacology between longer and shorter H3R isoforms should be considered in future drug discovery programs.
Collapse
Affiliation(s)
- Meichun Gao
- Department of Medicinal Chemistry, Amsterdam Institute of Molecular Life Sciences, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands
| | - Mabel E Dekker
- Department of Medicinal Chemistry, Amsterdam Institute of Molecular Life Sciences, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands
| | - Rob Leurs
- Department of Medicinal Chemistry, Amsterdam Institute of Molecular Life Sciences, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands.
| | - Henry F Vischer
- Department of Medicinal Chemistry, Amsterdam Institute of Molecular Life Sciences, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands.
| |
Collapse
|
2
|
Wang X, Neale C, Kim SK, Goddard WA, Ye L. Intermediate-state-trapped mutants pinpoint G protein-coupled receptor conformational allostery. Nat Commun 2023; 14:1325. [PMID: 36899002 PMCID: PMC10006191 DOI: 10.1038/s41467-023-36971-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 02/16/2023] [Indexed: 03/12/2023] Open
Abstract
Understanding the roles of intermediate states in signaling is pivotal to unraveling the activation processes of G protein-coupled receptors (GPCRs). However, the field is still struggling to define these conformational states with sufficient resolution to study their individual functions. Here, we demonstrate the feasibility of enriching the populations of discrete states via conformation-biased mutants. These mutants adopt distinct distributions among five states that lie along the activation pathway of adenosine A2A receptor (A2AR), a class A GPCR. Our study reveals a structurally conserved cation-π lock between transmembrane helix VI (TM6) and Helix8 that regulates cytoplasmic cavity opening as a "gatekeeper" for G protein penetration. A GPCR activation process based on the well-discerned conformational states is thus proposed, allosterically micro-modulated by the cation-π lock and a previously well-defined ionic interaction between TM3 and TM6. Intermediate-state-trapped mutants will also provide useful information in relation to receptor-G protein signal transduction.
Collapse
Affiliation(s)
- Xudong Wang
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL, 33620, USA
| | - Chris Neale
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Soo-Kyung Kim
- Materials and Process Simulation Center (139-74), California Institute of Technology, Pasadena, CA, 91125, USA
| | - William A Goddard
- Materials and Process Simulation Center (139-74), California Institute of Technology, Pasadena, CA, 91125, USA
| | - Libin Ye
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL, 33620, USA.
- H. Lee Moffitt Cancer Center & Research Institute, 12902 USF Magnolia Drive, Tampa, FL, 33612, USA.
| |
Collapse
|
3
|
Patidar I, Palaka BK, Katike U, Velmurugan Ilavarasi A, Tulsi, Mohanty SS, Ampasala DR. Structural elucidation of ETHR-A and ETHR-B from Plutella xylostella and insight into non-conservative mutations in transmembrane helix-6. J Biomol Struct Dyn 2023; 41:12572-12585. [PMID: 36683288 DOI: 10.1080/07391102.2023.2167112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 01/05/2023] [Indexed: 01/24/2023]
Abstract
The development of Diamondback moth (DBM) depends on the ecdysis triggering hormone receptor (ETHR); a neuronal membrane G-protein coupled receptor (GPCR) connected to the metamorphosis cascade. Lepidopteran insect DBM is an infamous pest of cruciferous plants. This study examined the full-length coding sequences (CDS) of PxETHR-A and PxETHR-B from the DBM genome. The three-dimensional (3 D) models of both receptors were generated in an inactive state. The behaviour and stability of receptors were examined using molecular dynamics simulations in a lipid membrane system for 300 ns and established a GPCR family-based view. Secondary interactions within receptors were studied to know more about factors contributing to their stability. Multiple sequence alignment revealed conserved features of insect ETHRs those compared to the GPCR family proteins. These features were helpful during the evaluation of the molecular models of both receptors. Side-chain orientation of conserved residues, non-conserved and conserved hydrogen-bond networks (HBN) and hydrophobic clusters were examined in the structures of both receptors. The non-conserved residues L6.35, T6.39, C/S6.43, and L6.48, are present in a conserved position on the transmembrane helix-6 (TM6) of ETHRs. In TM6, PxETHR-A and PxETHR-B differ at positions C/S6.43 and Y/F6.51, both being part of the HBN.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Ishwar Patidar
- Department of Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Bhagath Kumar Palaka
- Department of Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Umamahesh Katike
- Department of Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry, India
| | | | - Tulsi
- Department of Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Saswati Sarita Mohanty
- Department of Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Dinakara Rao Ampasala
- Department of Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry, India
| |
Collapse
|
4
|
Azam F, Bello M. Dynamic and thermodynamic impact of L94A, W100A, and W100L mutations on the D2 dopamine receptor bound to risperidone. RSC Adv 2022; 12:34359-34368. [PMID: 36545576 PMCID: PMC9709807 DOI: 10.1039/d2ra06694g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 11/22/2022] [Indexed: 12/02/2022] Open
Abstract
DRD2 is an important receptor in the mediation of antipsychotic drugs but also in Parkinson medication, hyperprolactinemia, nausea and vomiting. Recently, crystallographic studies of the DRD2-risperidone complex have provided important information about risperidone recognition in wild-type and different stabilizing DRD2-risperidone residues. Using the crystallographic structure of the DRD2-risperidone complex as a starting point, we undertook molecular dynamics (MD) simulations to investigate the structural and thermodynamic basis of molecular recognition by risperidone at the ligand-binding sites of wild-type and mutant DRD2. A solvated phospholipid bilayer was used to construct DRD2-risperidone complexes, which were then subjected to several microsecond (μs) MD simulations in order to obtain realistic receptor-ligand conformations under the equilibrated simulation time. Risperidone had a higher affinity for wild-type and L94A mutant DRD2 than the W100L and W100A mutants, according to binding free energy calculations using the Molecular Mechanics Generalized-Born Surface Area (MMGBSA) method, explaining the experimental differences in ligand residence times. Principal component (PC) analysis revealed important conformational mobility upon molecular recognition of risperidone for the L94A mutant compared to the wild type, indicating an unfavorable entropic component that may contribute to improving risperidone affinity in the L94A DRD2 mutant.
Collapse
Affiliation(s)
- Faizul Azam
- Department of Pharmaceutical Chemistry and Pharmacognosy, Unaizah College of Pharmacy, Qassim UniversityUnaizah51911Saudi Arabia
| | - Martiniano Bello
- Laboratorio de Diseño y Desarrollo de Nuevos Fármacos e Innovación Biotecnológica, Escuela Superior de Medicina, Instituto Politécnico NacionalPlan de San Luis y Diaz Mirón, S/N, Col. Casco de Santo TomasCiudad de México 11340Mexico
| |
Collapse
|
5
|
Mafi A, Kim SK, Goddard WA. The mechanism for ligand activation of the GPCR-G protein complex. Proc Natl Acad Sci U S A 2022; 119:e2110085119. [PMID: 35452328 PMCID: PMC9170043 DOI: 10.1073/pnas.2110085119] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 03/24/2022] [Indexed: 12/28/2022] Open
Abstract
G protein–coupled receptors (GPCRs) activate cellular responses ranging from odorants to neurotransmitters. Binding an agonist leads to activation of a heterotrimeric G protein (GP) that stimulates external signaling. Unfortunately, the mechanism remains unknown. We show for 15 class A GPCRs, including opioids, adrenergics, adenosines, chemokines, muscarinics, cannabinoids, serotonins, and dopamines, that interaction of an inactive GP, including Gs, Gi, Go, G11, and Gq, to the inactive GPCR, containing the intracellular ionic lock between transmembrane (TM) helices 3 and 6, evolves exothermically to form a precoupled GPCR-GP complex with an opened TM3-TM6 and the GP-α5 helix partially inserted into the GPCR but not activated. We show that binding of agonist to this precoupled GPCR-GP complex causes the Gα protein to open into its active form, with the guanosine diphosphate exposed for signaling. This GP-first paradigm provides a strategy for developing selective agonists for GPCRs since it is the pharmacophore for the precoupled GPCR-GP complex that should be used to design drugs.
Collapse
Affiliation(s)
- Amirhossein Mafi
- Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125
| | - Soo-Kyung Kim
- Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125
| | - William A. Goddard
- Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125
| |
Collapse
|
6
|
Casey AB, Cui M, Booth RG, Canal CE. "Selective" serotonin 5-HT 2A receptor antagonists. Biochem Pharmacol 2022; 200:115028. [PMID: 35381208 DOI: 10.1016/j.bcp.2022.115028] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/25/2022] [Accepted: 03/29/2022] [Indexed: 01/29/2023]
Abstract
Blockade of the serotonin 5-HT2A G protein-coupled receptor (5-HT2AR) is a fundamental pharmacological characteristic of numerous antipsychotic medications, which are FDA-approved to treat schizophrenia, bipolar disorder, and as adjunctive therapies in major depressive disorder. Meanwhile, activation of the 5-HT2AR by serotonergic psychedelics may be useful in treating neuropsychiatric indications, including major depressive and substance use disorders. Serotonergic psychedelics and other 5-HT2AR agonists, however, often bind other receptors, and standard 5-HT2AR antagonists lack sufficient selectivity to make well-founded mechanistic conclusions about the 5-HT2AR-dependent effects of these compounds and the general neurobiological function of 5-HT2ARs. This review discusses the limitations and strengths of currently available "selective" 5-HT2AR antagonists, the molecular determinants of antagonist selectivity at 5-HT2ARs, and the utility of molecular pharmacological and computational methods in guiding the discovery of novel unambiguously selective 5-HT2AR antagonists.
Collapse
Affiliation(s)
- Austen B Casey
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Meng Cui
- Department of Pharmaceutical Sciences, Boston, Massachusetts 02115, USA; Center for Drug Discovery, Northeastern University, Boston, Massachusetts 02115, USA
| | - Raymond G Booth
- Department of Pharmaceutical Sciences, Boston, Massachusetts 02115, USA; Department of Chemistry and Chemical Biology, Boston, Massachusetts 02115, USA; Center for Drug Discovery, Northeastern University, Boston, Massachusetts 02115, USA
| | - Clinton E Canal
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, 3001 Mercer University Drive, Atlanta, Georgia 30341, USA
| |
Collapse
|
7
|
Casey AB, Mukherjee M, McGlynn RP, Cui M, Kohut SJ, Booth RG. A new class of serotonin 5-HT 2A /5-HT 2C receptor inverse agonists: Synthesis, molecular modeling, in vitro and in vivo pharmacology of novel 2-aminotetralins. Br J Pharmacol 2021; 179:2610-2630. [PMID: 34837227 DOI: 10.1111/bph.15756] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 10/27/2021] [Accepted: 10/29/2021] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE The 5-HT receptor (5-HTR) subtypes 5-HT2A and 5-HT2C are important neurotherapeutic targets, though, obtaining selectivity over 5-HT2B and closely related histamine H1 Rs is challenging. Here, we delineated molecular determinants of selective binding to 5-HT2A and 5-HT2C Rs for novel 4-phenyl-2-dimethylaminotetralins (4-PATs). EXPERIMENTAL APPROACH We synthesized 42 novel 4-PATs with halogen or aryl moieties at the C(4)-phenyl meta position. Affinity, function, molecular modeling, and 5-HT2A R mutagenesis studies were undertaken to understand structure-activity relationships at 5-HT2 -type and H1 Rs. Lead 4-PAT-type selective 5-HT2A /5-HT2C R inverse agonists were compared to pimavanserin, a selective 5-HT2A /5-HT2C R inverse agonist approved to treat psychoses, in the mouse head twitch response, and locomotor activity assays, as models relevant to antipsychotic drug development. KEY RESULTS Most 4-PAT diastereomers in the (2S,4R)-configuration bound non-selectively to 5-HT2A , 5-HT2C, and H1 Rs, with >100-fold selectivity over 5-HT2B Rs, whereas, diastereomers in the (2R,4R)-configuration bound preferentially to 5-HT2A over 5-HT2C Rs and had >100-fold selectivity over 5-HT2B and H1 Rs. Results suggest that G2385.42 and V2355.39 in 5-HT2A Rs (conserved in 5-HT2C Rs) are important for high affinity binding, whereas, interactions with T1945.42 and W1584.56 determine H1 R affinity. The 4-PAT (2S,4R)-2k, a potent and selective 5-HT2A /5-HT2C R inverse agonist, had activity like pimavanserin in the mouse head-twitch response assay, but was distinct in not suppressing locomotor activity. CONCLUSIONS AND IMPLICATIONS We provide evidence that the novel 4-PAT chemotype can yield selective 5-HT2A /5-HT2C R inverse agonists for antipsychotic drug development by optimizing ligand-receptor interactions in transmembrane domain 5. We also show that chirality can be exploited to attain selectivity over H1 Rs which may circumvent sedative effects.
Collapse
Affiliation(s)
- Austen B Casey
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts, United States.,Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, United States.,Department of Chemistry & Chemical Biology, Northeastern University, Boston, Massachusetts, United States
| | - Munmun Mukherjee
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts, United States.,Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, United States.,Department of Chemistry & Chemical Biology, Northeastern University, Boston, Massachusetts, United States
| | - Ryan P McGlynn
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts, United States.,Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, United States.,Department of Chemistry & Chemical Biology, Northeastern University, Boston, Massachusetts, United States
| | - Meng Cui
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts, United States.,Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, United States
| | - Stephen J Kohut
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts, United States.,Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, United States.,Behavioral Neuroimaging Laboratory, McLean Hospital and Department of Psychiatry, Harvard Medical School, Belmont, Massachusetts, United States
| | - Raymond G Booth
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts, United States.,Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, United States.,Department of Chemistry & Chemical Biology, Northeastern University, Boston, Massachusetts, United States
| |
Collapse
|
8
|
Kim K, Che T, Panova O, DiBerto JF, Lyu J, Krumm BE, Wacker D, Robertson MJ, Seven AB, Nichols DE, Shoichet BK, Skiniotis G, Roth BL. Structure of a Hallucinogen-Activated Gq-Coupled 5-HT 2A Serotonin Receptor. Cell 2021; 182:1574-1588.e19. [PMID: 32946782 DOI: 10.1016/j.cell.2020.08.024] [Citation(s) in RCA: 249] [Impact Index Per Article: 83.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/17/2020] [Accepted: 08/14/2020] [Indexed: 02/07/2023]
Abstract
Hallucinogens like lysergic acid diethylamide (LSD), psilocybin, and substituted N-benzyl phenylalkylamines are widely used recreationally with psilocybin being considered as a therapeutic for many neuropsychiatric disorders including depression, anxiety, and substance abuse. How psychedelics mediate their actions-both therapeutic and hallucinogenic-are not understood, although activation of the 5-HT2A serotonin receptor (HTR2A) is key. To gain molecular insights into psychedelic actions, we determined the active-state structure of HTR2A bound to 25-CN-NBOH-a prototypical hallucinogen-in complex with an engineered Gαq heterotrimer by cryoelectron microscopy (cryo-EM). We also obtained the X-ray crystal structures of HTR2A complexed with the arrestin-biased ligand LSD or the inverse agonist methiothepin. Comparisons of these structures reveal determinants responsible for HTR2A-Gαq protein interactions as well as the conformational rearrangements involved in active-state transitions. Given the potential therapeutic actions of hallucinogens, these findings could accelerate the discovery of more selective drugs for the treatment of a variety of neuropsychiatric disorders.
Collapse
MESH Headings
- Animals
- Cryoelectron Microscopy
- Crystallography, X-Ray
- GTP-Binding Protein alpha Subunits, Gq-G11/chemistry
- GTP-Binding Protein alpha Subunits, Gq-G11/metabolism
- Gene Expression
- HEK293 Cells
- Hallucinogens/chemistry
- Hallucinogens/pharmacology
- Hallucinogens/therapeutic use
- Humans
- Ligands
- Lysergic Acid Diethylamide/chemistry
- Lysergic Acid Diethylamide/pharmacology
- Methiothepin/chemistry
- Methiothepin/metabolism
- Models, Chemical
- Mutation
- Protein Conformation, alpha-Helical
- Receptor, Serotonin, 5-HT2A/chemistry
- Receptor, Serotonin, 5-HT2A/genetics
- Receptor, Serotonin, 5-HT2A/metabolism
- Recombinant Proteins
- Serotonin/metabolism
- Spodoptera
Collapse
Affiliation(s)
- Kuglae Kim
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599-7365, USA
| | - Tao Che
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599-7365, USA
| | - Ouliana Panova
- Department of Molecular and Cellular Physiology, Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jeffrey F DiBerto
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599-7365, USA
| | - Jiankun Lyu
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Brian E Krumm
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599-7365, USA
| | - Daniel Wacker
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599-7365, USA
| | - Michael J Robertson
- Department of Molecular and Cellular Physiology, Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alpay B Seven
- Department of Molecular and Cellular Physiology, Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - David E Nichols
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599-7365, USA
| | - Brian K Shoichet
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Georgios Skiniotis
- Department of Molecular and Cellular Physiology, Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599-7365, USA; Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599-7365, USA.
| |
Collapse
|
9
|
Mio K, Fujimura S, Ishihara M, Kuramochi M, Sekiguchi H, Kubo T, Sasaki YC. Living-Cell Diffracted X-ray Tracking Analysis Confirmed Internal Salt Bridge Is Critical for Ligand-Induced Twisting Motion of Serotonin Receptors. Int J Mol Sci 2021; 22:ijms22105285. [PMID: 34067933 PMCID: PMC8157010 DOI: 10.3390/ijms22105285] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 12/18/2022] Open
Abstract
Serotonin receptors play important roles in neuronal excitation, emotion, platelet aggregation, and vasoconstriction. The serotonin receptor subtype 2A (5-HT2AR) is a Gq-coupled GPCR, which activate phospholipase C. Although the structures and functions of 5-HT2ARs have been well studied, little has been known about their real-time dynamics. In this study, we analyzed the intramolecular motion of the 5-HT2AR in living cells using the diffracted X-ray tracking (DXT) technique. The DXT is a very precise single-molecular analytical technique, which tracks diffraction spots from the gold nanocrystals labeled on the protein surface. Trajectory analysis provides insight into protein dynamics. The 5-HT2ARs were transiently expressed in HEK 293 cells, and the gold nanocrystals were attached to the N-terminal introduced FLAG-tag via anti-FLAG antibodies. The motions were recorded with a frame rate of 100 μs per frame. A lifetime filtering technique demonstrated that the unliganded receptors contain high mobility population with clockwise twisting. This rotation was, however, abolished by either a full agonist α-methylserotonin or an inverse agonist ketanserin. Mutation analysis revealed that the “ionic lock” between the DRY motif in the third transmembrane segment and a negatively charged residue of the sixth transmembrane segment is essential for the torsional motion at the N-terminus of the receptor.
Collapse
Affiliation(s)
- Kazuhiro Mio
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan; (S.F.); (M.I.); (M.K.); (T.K.)
- Correspondence: (K.M.); (Y.C.S.)
| | - Shoko Fujimura
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan; (S.F.); (M.I.); (M.K.); (T.K.)
| | - Masaki Ishihara
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan; (S.F.); (M.I.); (M.K.); (T.K.)
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
| | - Masahiro Kuramochi
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan; (S.F.); (M.I.); (M.K.); (T.K.)
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
| | - Hiroshi Sekiguchi
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Hyogo 679-5198, Japan;
| | - Tai Kubo
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan; (S.F.); (M.I.); (M.K.); (T.K.)
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
| | - Yuji C. Sasaki
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan; (S.F.); (M.I.); (M.K.); (T.K.)
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Hyogo 679-5198, Japan;
- Correspondence: (K.M.); (Y.C.S.)
| |
Collapse
|
10
|
Ma X, Segura MA, Zarzycka B, Vischer HF, Leurs R. Analysis of Missense Variants in the Human Histamine Receptor Family Reveals Increased Constitutive Activity of E410 6.30×30K Variant in the Histamine H 1 Receptor. Int J Mol Sci 2021; 22:ijms22073702. [PMID: 33918180 PMCID: PMC8038156 DOI: 10.3390/ijms22073702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/19/2021] [Accepted: 03/26/2021] [Indexed: 12/12/2022] Open
Abstract
The Exome Aggregation Consortium has collected the protein-encoding DNA sequences of almost 61,000 unrelated humans. Analysis of this dataset for G protein-coupled receptor (GPCR) proteins (available at GPCRdb) revealed a total of 463 naturally occurring genetic missense variations in the histamine receptor family. In this research, we have analyzed the distribution of these missense variations in the four histamine receptor subtypes concerning structural segments and sites important for GPCR function. Four missense variants R1273.52×52H, R13934.57×57H, R4096.29×29H, and E4106.30×30K, were selected for the histamine H1 receptor (H1R) that were hypothesized to affect receptor activity by interfering with the interaction pattern of the highly conserved D(E)RY motif, the so-called ionic lock. The E4106.30×30K missense variant displays higher constitutive activity in G protein signaling as compared to wild-type H1R, whereas the opposite was observed for R1273.52×52H, R13934.57×57H, and R4096.29×29H. The E4106.30×30K missense variant displays a higher affinity for the endogenous agonist histamine than wild-type H1R, whereas antagonist affinity was not affected. These data support the hypothesis that the E4106.30×30K mutation shifts the equilibrium towards active conformations. The study of these selected missense variants gives additional insight into the structural basis of H1R activation and, moreover, highlights that missense variants can result in pharmacologically different behavior as compared to wild-type receptors and should consequently be considered in the drug discovery process.
Collapse
|
11
|
Gao J, Xu X, Huang K, Liang Z. Fungal G-Protein-Coupled Receptors: A Promising Mediator of the Impact of Extracellular Signals on Biosynthesis of Ochratoxin A. Front Microbiol 2021; 12:631392. [PMID: 33643259 PMCID: PMC7907439 DOI: 10.3389/fmicb.2021.631392] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/21/2021] [Indexed: 01/17/2023] Open
Abstract
G-protein-coupled receptors (GPCRs) are transmembrane receptors involved in transducing signals from the external environment inside the cell, which enables fungi to coordinate cell transport, metabolism, and growth to promote their survival, reproduction, and virulence. There are 14 classes of GPCRs in fungi involved in sensing various ligands. In this paper, the synthesis of mycotoxins that are GPCR-mediated is discussed with respect to ligands, environmental stimuli, and intra-/interspecific communication. Despite their apparent importance in fungal biology, very little is known about the role of ochratoxin A (OTA) biosynthesis by Aspergillus ochraceus and the ligands that are involved. Fortunately, increasing evidence shows that the GPCR that involves the AF/ST (sterigmatocystin) pathway in fungi belongs to the same genus. Therefore, we speculate that GPCRs play an important role in a variety of environmental signals and downstream pathways in OTA biosynthesis. The verification of this inference will result in a more controllable GPCR target for control of fungal contamination in the future.
Collapse
Affiliation(s)
- Jing Gao
- Beijing Laboratory for Food Quality and Safety, Beijing, China
| | - Xinge Xu
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Kunlun Huang
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Zhihong Liang
- Beijing Laboratory for Food Quality and Safety, Beijing, China.,College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| |
Collapse
|
12
|
Sarkar P, Mozumder S, Bej A, Mukherjee S, Sengupta J, Chattopadhyay A. Structure, dynamics and lipid interactions of serotonin receptors: excitements and challenges. Biophys Rev 2020; 13:10.1007/s12551-020-00772-8. [PMID: 33188638 PMCID: PMC7930197 DOI: 10.1007/s12551-020-00772-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/05/2020] [Indexed: 12/13/2022] Open
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) is an intrinsically fluorescent neurotransmitter found in organisms spanning a wide evolutionary range. Serotonin exerts its diverse actions by binding to distinct cell membrane receptors which are classified into many groups. Serotonin receptors are involved in regulating a diverse array of physiological signaling pathways and belong to the family of either G protein-coupled receptors (GPCRs) or ligand-gated ion channels. Serotonergic signaling appears to play a key role in the generation and modulation of various cognitive and behavioral functions such as sleep, mood, pain, anxiety, depression, aggression, and learning. Serotonin receptors act as drug targets for a number of diseases, particularly neuropsychiatric disorders. The signaling mechanism and efficiency of serotonin receptors depend on their amazing ability to rapidly access multiple conformational states. This conformational plasticity, necessary for the wide variety of functions displayed by serotonin receptors, is regulated by binding to various ligands. In this review, we provide a succinct overview of recent developments in generating and analyzing high-resolution structures of serotonin receptors obtained using crystallography and cryo-electron microscopy. Capturing structures of distinct conformational states is crucial for understanding the mechanism of action of these receptors, which could provide important insight for rational drug design targeting serotonin receptors. We further provide emerging information and insight from studies on interactions of membrane lipids (such as cholesterol) with serotonin receptors. We envision that a judicious combination of analysis of high-resolution structures and receptor-lipid interaction would allow a comprehensive understanding of GPCR structure, function and dynamics, thereby leading to efficient drug discovery.
Collapse
Affiliation(s)
- Parijat Sarkar
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India
| | - Sukanya Mozumder
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, 700 032, India
- Academy of Scientific and Innovative Research, Ghaziabad, 201 002, India
| | - Aritra Bej
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, 700 032, India
| | - Sujoy Mukherjee
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, 700 032, India
| | - Jayati Sengupta
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, 700 032, India
- Academy of Scientific and Innovative Research, Ghaziabad, 201 002, India
| | | |
Collapse
|
13
|
Mio K, Ishihara M, Fujimura S, Sasaki D, Nozawa S, Ichiyanagi K, Fukaya R, Adachi SI, Kuramochi M, Sekiguchi H, Kubo T, Sasaki YC. X-ray-based living-cell motion analysis of individual serotonin receptors. Biochem Biophys Res Commun 2020; 529:306-313. [PMID: 32703428 DOI: 10.1016/j.bbrc.2020.05.200] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 05/26/2020] [Indexed: 01/14/2023]
Abstract
G protein-coupled receptors (GPCRs) are seven-transmembrane proteins, which transmit extracellular signals inside cells via activating G proteins. GPCRs are involved in a wide variety of physiological functions, such as signal sensing, immune system processes, and neurotransmission. Although the structures and functions of GPCRs have been well studied, little has been known about their real-time dynamics on live cells. In this study, we used Diffracted X-ray Tracking (DXT) and Diffracted X-ray Blinking (DXB) techniques for analysis. These methods are very precise single-molecular analytical techniques that elucidate protein dynamics by analyzing the diffraction spots from the gold nanocrystals labeled on the protein surface. DXT tracks diffraction spot movements, whereas DXB analyzes continuation of signals by calculating the autocorrelation function of each pixel from the recorded data. Serotonin receptor subtype 2A (5-HT2A receptors) were transiently expressed on HEK 293 cells, and the gold nanocrystals were attached to the N-terminally introduced FLAG-tag via anti-FLAG antibodies. Fast- and mid-range motions were recorded by DXT with 100μs and 1.25 ms/frame rate, respectively. Slow-range motion was obtained using the DXB method with 100 ms/frame rate. An agonist interestingly suppressed the fluctuations of 5-HT2A receptors at the microsecond-ranged fast measurement. On the contrary, the motion was enhanced by the agonist in the hundred-millisecond-ranged slow time scale. These dual-natured data may suggest that we succeeded in extracting different modes of receptor's motion on live cells; microsecond ranged fluctuation on the cell membrane, and millisecond-ranged dynamic movement comprising interactions with intracellular signaling molecules.
Collapse
Affiliation(s)
- Kazuhiro Mio
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba, 277-0882, Japan; Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), 2-3-26 Aomi, Tokyo, 135-0064, Japan.
| | - Masaki Ishihara
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba, 277-0882, Japan; Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba, 277-8561, Japan
| | - Shoko Fujimura
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba, 277-0882, Japan
| | - Daisuke Sasaki
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba, 277-8561, Japan
| | - Shunsuke Nozawa
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Kohei Ichiyanagi
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan; Division of Biophysics, Department of Physiology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan
| | - Ryo Fukaya
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Shin-Ichi Adachi
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Masahiro Kuramochi
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba, 277-0882, Japan; Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba, 277-8561, Japan
| | - Hiroshi Sekiguchi
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Hyogo, 679-5198, Japan
| | - Tai Kubo
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba, 277-0882, Japan; Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), 2-3-26 Aomi, Tokyo, 135-0064, Japan; Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba, 277-8561, Japan
| | - Yuji C Sasaki
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba, 277-0882, Japan; Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba, 277-8561, Japan; Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Hyogo, 679-5198, Japan.
| |
Collapse
|
14
|
De Deurwaerdère P, Bharatiya R, Chagraoui A, Di Giovanni G. Constitutive activity of 5-HT receptors: Factual analysis. Neuropharmacology 2020; 168:107967. [DOI: 10.1016/j.neuropharm.2020.107967] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/26/2019] [Accepted: 01/12/2020] [Indexed: 12/16/2022]
|
15
|
Structural basis of ligand recognition and self-activation of orphan GPR52. Nature 2020; 579:152-157. [PMID: 32076264 DOI: 10.1038/s41586-020-2019-0] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/23/2020] [Indexed: 11/08/2022]
Abstract
GPR52 is a class-A orphan G-protein-coupled receptor that is highly expressed in the brain and represents a promising therapeutic target for the treatment of Huntington's disease and several psychiatric disorders1,2. Pathological malfunction of GPR52 signalling occurs primarily through the heterotrimeric Gs protein2, but it is unclear how GPR52 and Gs couple for signal transduction and whether a native ligand or other activating input is required. Here we present the high-resolution structures of human GPR52 in three states: a ligand-free state, a Gs-coupled self-activation state and a potential allosteric ligand-bound state. Together, our structures reveal that extracellular loop 2 occupies the orthosteric binding pocket and operates as a built-in agonist, conferring an intrinsically high level of basal activity to GPR523. A fully active state is achieved when Gs is coupled to GPR52 in the absence of an external agonist. The receptor also features a side pocket for ligand binding. These insights into the structure and function of GPR52 could improve our understanding of other self-activated GPCRs, enable the identification of endogenous and tool ligands, and guide drug discovery efforts that target GPR52.
Collapse
|
16
|
Phenylethylamides derived from bacterial secondary metabolites specifically inhibit an insect serotonin receptor. Sci Rep 2019; 9:20358. [PMID: 31885035 PMCID: PMC6935581 DOI: 10.1038/s41598-019-56892-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 12/16/2019] [Indexed: 01/02/2023] Open
Abstract
Serotonin (5-hydroxytryptamine: 5-HT) is a biogenic monoamine that mediates immune responses and modulates nerve signal in insects. Se-5HTR, a specific receptor of serotonin, has been identified in the beet armyworm, Spodoptera exigua. It is classified into subtype 7 among known 5HTRs. Se-5HTR was expressed in all developmental stages of S. exigua. It was expressed in all tested tissues of larval stage. Its expression was up-regulated in hemocytes and fat body in response to immune challenge. RNA interference (RNAi) of Se-5HTR exhibited significant immunosuppression by preventing cellular immune responses such as phagocytosis and nodulation. Treatment with an inhibitor (SB-269970) specific to 5HTR subtype 7 resulted in significant immunosuppression. Furthermore, knockout mutant of Se-5HTR by CRISPR-Cas9 led to significant reduction of phagocytotic activity of S. exigua hemocytes. Such immunosuppression was also induced by bacterial secondary metabolites derived from Xenorhabdus and Photorhabdus. To determine specific bacterial metabolites inhibiting Se-5HTR, this study screened 37 bacterial secondary metabolites with respect to cellular immune responses associated with Se-5HTR and selected 10 potent inhibitors. These 10 selected compounds competitively inhibited cellular immune responses against 5-HT and shared phenylethylamide (PEA) chemical skeleton. Subsequently, 46 PEA derivatives were screened and resulting potent chemicals were used to design a compound to be highly inhibitory against Se-5HTR. The designed compound was chemically synthesized. It showed high immunosuppressive activities along with specific and competitive inhibition activity for Se-5HTR. This study reports the first 5HT receptor from S. exigua and provides its specific inhibitor designed from bacterial metabolites and their derivatives.
Collapse
|
17
|
Jing M, Zhang Y, Wang H, Li Y. G-protein-coupled receptor-based sensors for imaging neurochemicals with high sensitivity and specificity. J Neurochem 2019; 151:279-288. [PMID: 31419844 PMCID: PMC6819231 DOI: 10.1111/jnc.14855] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 08/01/2019] [Accepted: 08/01/2019] [Indexed: 01/02/2023]
Abstract
Neurotransmitters and neuromodulators are key neurochemicals that mediate cell-cell communication, maintain the body's homeostasis, and control a wide range of biological processes. Thus, dysregulation of neurochemical signaling is associated with a range of psychiatric disorders and neurological diseases. Understanding the physiological and pathophysiological functions of neurochemicals, particularly in complex biological systems in vivo, requires tools that can probe their dynamics with high sensitivity and specificity. Recently, genetically encoded fluorescent sensors for visualizing specific neurochemicals were developed by coupling neurochemical-sensing G-protein-coupled receptors (GPCRs) with a circular-permutated fluorescent protein. These GPCR-based sensors can monitor the dynamics of neurochemicals in behaving animals with high spatiotemporal resolution. Here, we review recent progress regarding the development and application of GPCR-based sensors for imaging neurochemicals, and we discuss future perspectives.
Collapse
Affiliation(s)
- Miao Jing
- Chinese Institute for Brain Research, Beijing, China
| | - Yajun Zhang
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Beijing, China
| | - Huan Wang
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| |
Collapse
|
18
|
Molecular pharmacology of metabotropic receptors targeted by neuropsychiatric drugs. Nat Struct Mol Biol 2019; 26:535-544. [PMID: 31270468 DOI: 10.1038/s41594-019-0252-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 05/15/2019] [Indexed: 12/30/2022]
Abstract
Metabotropic receptors are responsible for so-called 'slow synaptic transmission' and mediate the effects of hundreds of peptide and non-peptide neurotransmitters and neuromodulators. Over the past decade or so, a revolution in membrane-protein structural determination has clarified the molecular determinants responsible for the actions of these receptors. This Review focuses on the G protein-coupled receptors (GPCRs) that are targets of neuropsychiatric drugs and shows how insights into the structure and function of these important synaptic proteins are accelerating understanding of their actions. Notably, elucidating the structure and function of GPCRs should enhance the structure-guided discovery of novel chemical tools with which to manipulate and understand these synaptic proteins.
Collapse
|
19
|
Sensing and transduction of nutritional and chemical signals in filamentous fungi: Impact on cell development and secondary metabolites biosynthesis. Biotechnol Adv 2019; 37:107392. [PMID: 31034961 DOI: 10.1016/j.biotechadv.2019.04.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 04/22/2019] [Accepted: 04/25/2019] [Indexed: 11/23/2022]
Abstract
Filamentous fungi respond to hundreds of nutritional, chemical and environmental signals that affect expression of primary metabolism and biosynthesis of secondary metabolites. These signals are sensed at the membrane level by G protein coupled receptors (GPCRs). GPCRs contain usually seven transmembrane domains, an external amino terminal fragment that interacts with the ligand, and an internal carboxy terminal end interacting with the intracellular G protein. There is a great variety of GPCRs in filamentous fungi involved in sensing of sugars, amino acids, cellulose, cell-wall components, sex pheromones, oxylipins, calcium ions and other ligands. Mechanisms of signal transduction at the membrane level by GPCRs are discussed, including the internalization and compartmentalisation of these sensor proteins. We have identified and analysed the GPCRs in the genome of Penicillium chrysogenum and compared them with GPCRs of several other filamentous fungi. We have found 66 GPCRs classified into 14 classes, depending on the ligand recognized by these proteins, including most previously proposed classes of GPCRs. We have found 66 putative GPCRs, representatives of twelve of the fourteen previously proposed classes of GPCRs, depending on the ligand recognized by these proteins. A staggering fortytwo putative members of the new GPCR class XIV, the so-called Pth11 sensors of cellulosic material as reported for Neurospora crassa and some other fungi, were identified. Several GPCRs sensing sex pheromones, known in yeast and in several fungi, were also identified in P. chrysogenum, confirming the recent unravelling of the hidden sexual capacity of this species. Other sensing mechanisms do not involve GPCRs, including the two-component systems (HKRR), the HOG signalling system and the PalH mediated pH transduction sensor. GPCR sensor proteins transmit their signals by interacting with intracellular heterotrimeric G proteins, that are well known in several fungi, including P. chrysogenum. These G proteins are inactive in the GDP containing heterotrimeric state, and become active by nucleotide exchange, allowing the separation of the heterotrimeric protein in active Gα and Gβγ dimer subunits. The conversion of GTP in GDP is mediated by the endogenous GTPase activity of the G proteins. Downstream of the ligand interaction, the activated Gα protein and also the Gβ/Gγ dimer, transduce the signals through at least three different cascades: adenylate cyclase/cAMP, MAPK kinase, and phospholipase C mediated pathways.
Collapse
|
20
|
Structural insights into serotonin receptor ligands polypharmacology. Eur J Med Chem 2018; 151:797-814. [DOI: 10.1016/j.ejmech.2018.04.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 04/02/2018] [Accepted: 04/03/2018] [Indexed: 02/03/2023]
|
21
|
Wang S, Che T, Levit A, Shoichet BK, Wacker D, Roth BL. Structure of the D2 dopamine receptor bound to the atypical antipsychotic drug risperidone. Nature 2018; 555:269-273. [PMID: 29466326 PMCID: PMC5843546 DOI: 10.1038/nature25758] [Citation(s) in RCA: 293] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 01/18/2018] [Indexed: 01/07/2023]
Abstract
Dopamine is a neurotransmitter that has been implicated in processes as diverse as reward, addiction, control of coordinated movement, metabolism and hormonal secretion. Correspondingly, dysregulation of the dopaminergic system has been implicated in diseases such as schizophrenia, Parkinson's disease, depression, attention deficit hyperactivity disorder, and nausea and vomiting. The actions of dopamine are mediated by a family of five G-protein-coupled receptors. The D2 dopamine receptor (DRD2) is the primary target for both typical and atypical antipsychotic drugs, and for drugs used to treat Parkinson's disease. Unfortunately, many drugs that target DRD2 cause serious and potentially life-threatening side effects due to promiscuous activities against related receptors. Accordingly, a molecular understanding of the structure and function of DRD2 could provide a template for the design of safer and more effective medications. Here we report the crystal structure of DRD2 in complex with the widely prescribed atypical antipsychotic drug risperidone. The DRD2-risperidone structure reveals an unexpected mode of antipsychotic drug binding to dopamine receptors, and highlights structural determinants that are essential for the actions of risperidone and related drugs at DRD2.
Collapse
Affiliation(s)
- Sheng Wang
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599-7365, USA
| | - Tao Che
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599-7365, USA
| | - Anat Levit
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, 94158-2280, USA
| | - Brian K. Shoichet
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, 94158-2280, USA
| | - Daniel Wacker
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599-7365, USA
| | - Bryan L. Roth
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599-7365, USA
- Division of Chemical Biology & Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7360, USA
- National Institute of Mental Health Psychoactive Drug Screening Program (NIMH PDSP), School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7365, USA
| |
Collapse
|
22
|
Affiliation(s)
- Naomi R. Latorraca
- Department of Computer Science, ‡Biophysics Program, §Department of Molecular
and Cellular
Physiology, and ∥Institute for Computational and Mathematical Engineering, Stanford University, Stanford, California 94305, United States
| | - A. J. Venkatakrishnan
- Department of Computer Science, ‡Biophysics Program, §Department of Molecular
and Cellular
Physiology, and ∥Institute for Computational and Mathematical Engineering, Stanford University, Stanford, California 94305, United States
| | - Ron O. Dror
- Department of Computer Science, ‡Biophysics Program, §Department of Molecular
and Cellular
Physiology, and ∥Institute for Computational and Mathematical Engineering, Stanford University, Stanford, California 94305, United States
| |
Collapse
|
23
|
Sullivan LC, Clarke WP, Berg KA. Atypical antipsychotics and inverse agonism at 5-HT2 receptors. Curr Pharm Des 2016; 21:3732-8. [PMID: 26044975 DOI: 10.2174/1381612821666150605111236] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 06/04/2015] [Indexed: 11/22/2022]
Abstract
It is now well accepted that receptors can regulate cellular signaling pathways in the absence of a stimulating ligand, and inverse agonists can reduce this ligand-independent or "constitutive" receptor activity. Both the serotonin 5-HT2A and 5-HT2C receptors have demonstrated constitutive receptor activity in vitro and in vivo. Each has been identified as a target for treatment of schizophrenia. Further, most, if not all, atypical antipsychotic drugs have inverse agonist properties at both 5-HT2A and 5-HT2C receptors. This paper describes our current knowledge of inverse agonism of atypical antipsychotics at 5-HT2A/2C receptor subtypes in vitro and in vivo. Exploiting inverse agonist properties of APDs may provide new avenues for drug development.
Collapse
Affiliation(s)
| | | | - Kelly A Berg
- Department of Pharmacology - MS 7764, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
| |
Collapse
|
24
|
Lee HM, Kim Y. Drug Repurposing Is a New Opportunity for Developing Drugs against Neuropsychiatric Disorders. SCHIZOPHRENIA RESEARCH AND TREATMENT 2016; 2016:6378137. [PMID: 27073698 PMCID: PMC4814692 DOI: 10.1155/2016/6378137] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/24/2016] [Indexed: 01/03/2023]
Abstract
Better the drugs you know than the drugs you do not know. Drug repurposing is a promising, fast, and cost effective method that can overcome traditional de novo drug discovery and development challenges of targeting neuropsychiatric and other disorders. Drug discovery and development targeting neuropsychiatric disorders are complicated because of the limitations in understanding pathophysiological phenomena. In addition, traditional de novo drug discovery and development are risky, expensive, and time-consuming processes. One alternative approach, drug repurposing, has emerged taking advantage of off-target effects of the existing drugs. In order to identify new opportunities for the existing drugs, it is essential for us to understand the mechanisms of action of drugs, both biologically and pharmacologically. By doing this, drug repurposing would be a more effective method to develop drugs against neuropsychiatric and other disorders. Here, we review the difficulties in drug discovery and development in neuropsychiatric disorders and the extent and perspectives of drug repurposing.
Collapse
Affiliation(s)
- Hyeong-Min Lee
- Department of Cell Biology & Physiology, School of Medicine, University of North Carolina, 115 Mason Farm Road, Chapel Hill, NC 27599, USA
| | - Yuna Kim
- Department of Pediatrics, School of Medicine, Duke University, 905 S. LaSalle Street, Durham, NC 27710, USA
| |
Collapse
|
25
|
|
26
|
Culhane KJ, Liu Y, Cai Y, Yan ECY. Transmembrane signal transduction by peptide hormones via family B G protein-coupled receptors. Front Pharmacol 2015; 6:264. [PMID: 26594176 PMCID: PMC4633518 DOI: 10.3389/fphar.2015.00264] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 10/23/2015] [Indexed: 01/28/2023] Open
Abstract
Although family B G protein-coupled receptors (GPCRs) contain only 15 members, they play key roles in transmembrane signal transduction of hormones. Family B GPCRs are drug targets for developing therapeutics for diseases ranging from metabolic to neurological disorders. Despite their importance, the molecular mechanism of activation of family B GPCRs remains largely unexplored due to the challenges in expression and purification of functional receptors to the quantity for biophysical characterization. Currently, there is no crystal structure available of a full-length family B GPCR. However, structures of key domains, including the extracellular ligand binding regions and seven-helical transmembrane regions, have been solved by X-ray crystallography and NMR, providing insights into the mechanisms of ligand recognition and selectivity, and helical arrangements within the cell membrane. Moreover, biophysical and biochemical methods have been used to explore functions, key residues for signaling, and the kinetics and dynamics of signaling processes. This review summarizes the current knowledge of the signal transduction mechanism of family B GPCRs at the molecular level and comments on the challenges and outlook for mechanistic studies of family B GPCRs.
Collapse
Affiliation(s)
- Kelly J Culhane
- Department of Molecular Biophysics and Biochemistry, Yale University New Haven, CT, USA
| | - Yuting Liu
- Department of Chemistry, Yale University New Haven, CT, USA
| | - Yingying Cai
- Department of Chemistry, Yale University New Haven, CT, USA
| | - Elsa C Y Yan
- Department of Chemistry, Yale University New Haven, CT, USA
| |
Collapse
|
27
|
Nocjar C, Alex KD, Sonneborn A, Abbas AI, Roth BL, Pehek EA. Serotonin-2C and -2a receptor co-expression on cells in the rat medial prefrontal cortex. Neuroscience 2015; 297:22-37. [PMID: 25818050 PMCID: PMC4595040 DOI: 10.1016/j.neuroscience.2015.03.050] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Revised: 03/20/2015] [Accepted: 03/20/2015] [Indexed: 11/28/2022]
Abstract
Neural function within the medial prefrontal cortex (mPFC) regulates normal cognition, attention and impulse control, implicating neuroregulatory abnormalities within this region in mental dysfunction related to schizophrenia, depression and drug abuse. Both serotonin-2A (5-HT2A) and -2C (5-HT2C) receptors are known to be important in neuropsychiatric drug action and are distributed throughout the mPFC. However, their interactive role in serotonergic cortical regulation is poorly understood. While the main signal transduction mechanism for both receptors is stimulation of phosphoinositide production, they can have opposite effects downstream. 5-HT2A versus 5-HT2C receptor activation oppositely regulates behavior and can oppositely affect neurochemical release within the mPFC. These distinct receptor effects could be caused by their differential cellular distribution within the cortex and/or other areas. It is known that both receptors are located on GABAergic and pyramidal cells within the mPFC, but it is not clear whether they are expressed on the same or different cells. The present work employed immunofluorescence with confocal microscopy to examine this in layers V-VI of the prelimbic mPFC. The majority of GABA cells in the deep prelimbic mPFC expressed 5-HT2C receptor immunoreactivity. Furthermore, most cells expressing 5-HT2C receptor immunoreactivity notably co-expressed 5-HT2A receptors. However, 27% of 5-HT2C receptor immunoreactive cells were not GABAergic, indicating that a population of prelimbic pyramidal projection cells could express the 5-HT2C receptor. Indeed, some cells with 5-HT2C and 5-HT2A receptor co-labeling had a pyramidal shape and were expressed in the typical layered fashion of pyramidal cells. This indirectly demonstrates that 5-HT2C and 5-HT2A receptors may be commonly co-expressed on GABAergic cells within the deep layers of the prelimbic mPFC and perhaps co-localized on a small population of local pyramidal projection cells. Thus a complex interplay of cortical 5-HT2A and 5-HT2C receptor mechanisms exists, which if altered, could modulate efferent brain systems implicated in mental illness.
Collapse
Affiliation(s)
- C Nocjar
- Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA; Department of Psychiatry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
| | - K D Alex
- Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA; Department of Neurosciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
| | - A Sonneborn
- Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA.
| | - A I Abbas
- Department of Psychiatry, Columbia University, New York, NY 10032, USA; Division of Integrative Neuroscience, New York State Psychiatric Institute, New York, NY 10032, USA.
| | - B L Roth
- Department of Pharmacology, University of North Carolina-Chapel Hill School of Medicine, 120 Mason Farm Road, 4072 Genetic Medicine Building, Campus Box 7365, Chapel Hill, NC 27599-7365, USA.
| | - E A Pehek
- Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA; Department of Neurosciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Department of Psychiatry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
| |
Collapse
|
28
|
McCorvy JD, Roth BL. Structure and function of serotonin G protein-coupled receptors. Pharmacol Ther 2015; 150:129-42. [PMID: 25601315 DOI: 10.1016/j.pharmthera.2015.01.009] [Citation(s) in RCA: 228] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 12/12/2014] [Indexed: 12/18/2022]
Abstract
Serotonin receptors are prevalent throughout the nervous system and the periphery, and remain one of the most lucrative and promising drug discovery targets for disorders ranging from migraine headaches to neuropsychiatric disorders such as schizophrenia and depression. There are 14 distinct serotonin receptors, of which 13 are G protein-coupled receptors (GPCRs), which are targets for approximately 40% of the approved medicines. Recent crystallographic and biochemical evidence has provided a converging understanding of the basic structure and functional mechanics of GPCR activation. Currently, two GPCR crystal structures exist for the serotonin family, the 5-HT1B and 5-HT2B receptor, with the antimigraine and valvulopathic drug ergotamine bound. The first serotonin crystal structures not only provide the first evidence of serotonin receptor topography but also provide mechanistic explanations into functional selectivity or biased agonism. This review will detail the findings of these crystal structures from a molecular and mutagenesis perspective for driving rational drug design for novel therapeutics incorporating biased signaling.
Collapse
MESH Headings
- Allosteric Site
- Animals
- Ergotamine/pharmacology
- Ergotamine/therapeutic use
- GTP-Binding Proteins/physiology
- Heart Valve Diseases/drug therapy
- Heart Valve Diseases/metabolism
- Humans
- Migraine Disorders/drug therapy
- Migraine Disorders/metabolism
- Models, Molecular
- Protein Conformation
- Receptor, Serotonin, 5-HT1B/chemistry
- Receptor, Serotonin, 5-HT1B/metabolism
- Receptor, Serotonin, 5-HT2B/chemistry
- Receptor, Serotonin, 5-HT2B/metabolism
- Receptors, Serotonin/chemistry
- Receptors, Serotonin/metabolism
- Serotonin Receptor Agonists/pharmacology
- Serotonin Receptor Agonists/therapeutic use
- Signal Transduction
- Vasoconstrictor Agents/pharmacology
- Vasoconstrictor Agents/therapeutic use
Collapse
Affiliation(s)
- John D McCorvy
- Department of Pharmacology and Division of Chemical Biology and Medicinal Chemistry, University of North Carolina Chapel Hill Medical School, Chapel Hill, NC 27514, USA
| | - Bryan L Roth
- Department of Pharmacology and Division of Chemical Biology and Medicinal Chemistry, University of North Carolina Chapel Hill Medical School, Chapel Hill, NC 27514, USA
| |
Collapse
|
29
|
Helal MA, Darwish KM, Hammad MA. Homology modeling and explicit membrane molecular dynamics simulation to delineate the mode of binding of thiazolidinediones into FFAR1 and the mechanism of receptor activation. Bioorg Med Chem Lett 2014; 24:5330-6. [DOI: 10.1016/j.bmcl.2014.07.043] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Revised: 07/13/2014] [Accepted: 07/15/2014] [Indexed: 12/21/2022]
|
30
|
On the discovery and development of pimavanserin: a novel drug candidate for Parkinson's psychosis. Neurochem Res 2014; 39:2008-17. [PMID: 24682754 PMCID: PMC4172996 DOI: 10.1007/s11064-014-1293-3] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Revised: 03/19/2014] [Accepted: 03/21/2014] [Indexed: 12/30/2022]
Abstract
Parkinson’s disease psychosis (PDP) is a condition that may develop in up to 60 % of Parkinson’s patients, and is a major reason for nursing home placement for those affected. There are no FDA approved drugs for PDP but low doses of atypical anti-psychotic drugs (APDs) are commonly prescribed off-label. Only low-dose clozapine has shown efficacy in randomized controlled trials, but all APDs have black box warnings related to the increased mortality and morbidity when used in elderly demented patients. Using molecular pharmacological profiling of a large collection of marketed drugs, we discovered that potent inverse agonist activity against 5-HT2A serotonin receptors was a common feature of atypical APDs, especially the atypical APDs used to treat PDP. Since low-dose clozapine therapy selectively blocks this receptor, it was hypothesized that a highly selective 5-HT2A receptor inverse agonist might provide good symptom control in patients suffering from PDP, with a greatly improved safety and tolerability profile. A high throughput screening and subsequent chemical lead optimization campaign to develop potent, selective 5-HT2A receptor inverse agonists was launched, eventually resulting in the discovery of pimavanserin. Pimavanserin displays nanomolar potency as a 5-HT2A receptor inverse agonist, selectivity for 5-HT2A over 5-HT2C receptors, and no meaningful activity at any other G-protein coupled receptor. It demonstrated robust activity in preclinical models of schizophrenia and PDP, and did not worsen motoric symptoms, in contrast to the APDs tested. In a Phase III clinical trial, pimavanserin showed highly significant benefits in the primary endpoint, the scale for assessment of positive symptoms-PD, a scale adapted for use in PDP. In addition, improvements in all other efficacy endpoints, including physician’s clinical global impression, caregiver burden, night-time sleep quality and daytime wakefulness, were seen. Pimavanserin demonstrated good safety and tolerability and did not worsen motoric symptoms as assessed by the unified Parkinson’s disease rating scale parts II and III. An open-label extension study has further demonstrated that pimavanserin is safe and well-tolerated with long-term use. Pimavanserin may therefore offer a viable treatment option for patients suffering from PDP.
Collapse
|
31
|
Tehan BG, Bortolato A, Blaney FE, Weir MP, Mason JS. Unifying family A GPCR theories of activation. Pharmacol Ther 2014; 143:51-60. [PMID: 24561131 DOI: 10.1016/j.pharmthera.2014.02.004] [Citation(s) in RCA: 145] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 02/05/2014] [Indexed: 10/25/2022]
Abstract
Several new pairs of active and inactive GPCR structures have recently been solved enabling detailed structural insight into the activation process, not only of rhodopsin but now also of the β2 adrenergic, M2 muscarinic and adenosine A2A receptors. Combined with structural analyses they have enabled us to examine the different recent theories proposed for GPCR activation and show that they are all indeed parts of the same process, and are intrinsically related through their effect on the central hydrophobic core of GPCRs. This new unifying general process of activation is consistent with the identification of known constitutively active mutants and an in-depth conservational analysis of significant residues implicated in the process.
Collapse
Affiliation(s)
- Benjamin G Tehan
- Heptares Therapeutics BioPark, Broadwater Road, Welwyn Garden City AL7 3AX United Kingdom.
| | - Andrea Bortolato
- Heptares Therapeutics BioPark, Broadwater Road, Welwyn Garden City AL7 3AX United Kingdom
| | - Frank E Blaney
- Heptares Therapeutics BioPark, Broadwater Road, Welwyn Garden City AL7 3AX United Kingdom
| | - Malcolm P Weir
- Heptares Therapeutics BioPark, Broadwater Road, Welwyn Garden City AL7 3AX United Kingdom
| | - Jonathan S Mason
- Heptares Therapeutics BioPark, Broadwater Road, Welwyn Garden City AL7 3AX United Kingdom
| |
Collapse
|
32
|
Pruitt MM, Lamm MH, Coffman CR. Molecular dynamics simulations on the Tre1 G protein-coupled receptor: exploring the role of the arginine of the NRY motif in Tre1 structure. BMC STRUCTURAL BIOLOGY 2013; 13:15. [PMID: 24044607 PMCID: PMC3848830 DOI: 10.1186/1472-6807-13-15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 09/16/2013] [Indexed: 11/10/2022]
Abstract
BACKGROUND The arginine of the D/E/NRY motif in Rhodopsin family G protein-coupled receptors (GPCRs) is conserved in 96% of these proteins. In some GPCRs, this arginine in transmembrane 3 can form a salt bridge with an aspartic acid or glutamic acid in transmembrane 6. The Drosophila melanogaster GPCR Trapped in endoderm-1 (Tre1) is required for normal primordial germ cell migration. In a mutant form of the protein, Tre1sctt, eight amino acids RYILIACH are missing, resulting in a severe disruption of primordial germ cell development. The impact of the loss of these amino acids on Tre1 structure is unknown. Since the missing amino acids in Tre1sctt include the arginine that is part of the D/E/NRY motif in Tre1, molecular dynamics simulations were performed to explore the hypothesis that these amino acids are involved in salt bridge formation and help maintain Tre1 structure. RESULTS Structural predictions of wild type Tre1 (Tre1+) and Tre1sctt were subjected to over 250 ns of molecular dynamics simulations. The ability of the model systems to form a salt bridge between the arginine of the D/E/NRY motif and an aspartic acid residue in transmembrane 6 was analyzed. The results indicate that a stable salt bridge can form in the Tre1+ systems and a weak salt bridge or no salt bridge, using an alternative arginine, is likely in the Tre1sctt systems. CONCLUSIONS The weak salt bridge or lack of a salt bridge in the Tre1sctt systems could be one possible explanation for the disrupted function of Tre1sctt in primordial germ cell migration. These results provide a framework for studying the importance of the arginine of the D/E/NRY motif in the structure and function of other GPCRs that are involved in cell migration, such as CXCR4 in the mouse, zebrafish, and chicken.
Collapse
Affiliation(s)
- Margaret M Pruitt
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA
| | - Monica H Lamm
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011, USA
| | - Clark R Coffman
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA
| |
Collapse
|
33
|
Levit A, Barak D, Behrens M, Meyerhof W, Niv MY. Homology model-assisted elucidation of binding sites in GPCRs. Methods Mol Biol 2013; 914:179-205. [PMID: 22976029 DOI: 10.1007/978-1-62703-023-6_11] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
G protein-coupled receptors (GPCRs) are important mediators of cell signaling and a major family of drug targets. Despite recent breakthroughs, experimental elucidation of GPCR structures remains a formidable challenge. Homology modeling of 3D structures of GPCRs provides a practical tool for elucidating the structural determinants governing the interactions of these important receptors with their ligands. The working model of the binding site can then be used for virtual screening of additional ligands that may fit this site, for determining and comparing specificity profiles of related receptors, and for structure-based design of agonists and antagonists. The current review presents the protocol and enumerates the steps for modeling and validating the residues involved in ligand binding. The main stages include (a) modeling the receptor structure using an automated fragment-based approach, (b) predicting potential binding pockets, (c) docking known binders, (d) analyzing predicted interactions and comparing with positions that have been shown to bind ligands in other receptors, (e) validating the structural model by mutagenesis.
Collapse
Affiliation(s)
- Anat Levit
- Institute of Biochemistry, Food Science, and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot, Israel
| | | | | | | | | |
Collapse
|
34
|
Caltabiano G, Gonzalez A, Cordomí A, Campillo M, Pardo L. The Role of Hydrophobic Amino Acids in the Structure and Function of the Rhodopsin Family of G Protein-Coupled Receptors. Methods Enzymol 2013; 520:99-115. [DOI: 10.1016/b978-0-12-391861-1.00005-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
|
35
|
Leschner J, Wennerberg G, Feierler J, Bermudez M, Welte B, Kalatskaya I, Wolber G, Faussner A. Interruption of the Ionic Lock in the Bradykinin B2 Receptor Results in Constitutive Internalization and Turns Several Antagonists into Strong Agonists. J Pharmacol Exp Ther 2012; 344:85-95. [DOI: 10.1124/jpet.112.199190] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
|
36
|
Gong Y, Fu W, Chen K. Dopamine D1receptor and serotonin 5-HT1Areceptor agonist effects of the natural product (–)-stepholidine: molecular modelling and dynamics simulations. MOLECULAR SIMULATION 2012. [DOI: 10.1080/08927022.2012.679619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
37
|
Wang CIA, Lewis RJ. Emerging opportunities for allosteric modulation of G-protein coupled receptors. Biochem Pharmacol 2012; 85:153-62. [PMID: 22975406 DOI: 10.1016/j.bcp.2012.09.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 09/03/2012] [Accepted: 09/04/2012] [Indexed: 12/23/2022]
Abstract
Their ubiquitous nature, wide cellular distribution and versatile molecular recognition and signalling help make G-protein binding receptors (GPCRs) the most important class of membrane proteins in clinical medicine, accounting for ∼40% of all current therapeutics. A large percentage of current drugs target the endogenous ligand binding (orthosteric) site, which are structurally and evolutionarily conserved, particularly among members of the same GPCR subfamily. With the recent advances in GPCR X-ray crystallography, new opportunities for developing novel subtype selective drugs have emerged. Given the increasing recognition that the extracellular surface conformation changes in response to ligand binding, it is likely that all GPCRs possess an allosteric site(s) capable of regulating GPCR signalling. Allosteric sites are less structurally conserved than their corresponding orthosteric site and thus provide new opportunities for the development of more selective drugs. Constitutive oligomerisation (dimerisation) identified in many of the GPCRs investigated, adds another dimension to the structural and functional complexity of GPCRs. In this review, we compare 60 crystal structures of nine GPCR subtypes (rhodopsin, ß₂-AR, ß₁-AR, A(2a)-AR, CXCR4, D₃R, H₁R, M₂R, M₃R) across four subfamilies of Class A GPCRs, and discuss mechanisms involved in receptor activation and potential allosteric binding sites across the highly variable extracellular surface of these GPCRs. This analysis has identified a new extracellular salt bridge (ESB-2) that might be exploited in the design of allosteric modulators.
Collapse
Affiliation(s)
- Ching-I Anderson Wang
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD 4072 Australia
| | | |
Collapse
|
38
|
Gaffuri AL, Ladarre D, Lenkei Z. Type-1 cannabinoid receptor signaling in neuronal development. Pharmacology 2012; 90:19-39. [PMID: 22776780 DOI: 10.1159/000339075] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 04/13/2012] [Indexed: 01/21/2023]
Abstract
The type-1 cannabinoid receptor (CB1R) was initially identified as the neuronal target of Δ(9)-tetrahydrocannabinol (THC), the major psychoactive substance of marijuana. This receptor is one of the most abundant G-protein-coupled receptors in the adult brain, the target of endocannabinoid ligands and a well-characterized retrograde synaptic regulator. However, CB1Rs are also highly and often transiently expressed in neuronal populations in the embryonic and early postnatal brain, even before the formation of synapses. This suggests important physiological roles for CB1Rs during neuronal development. Several recent reviews have summarized our knowledge about the role of the endocannabinoid (eCB) system in neurodevelopment and neurotransmission by focusing on the metabolism of endocannabinoid molecules. Here, we review current knowledge about the effects of the modulation of CB1R signaling during the different phases of brain development. More precisely, we focus on reports that directly implicate CB1Rs during progenitor cell migration and differentiation, neurite outgrowth, axonal pathfinding and synaptogenesis. Based on theoretical considerations and on the reviewed experimental data, we propose a new model to explain the diversity of experimental findings on eCB signaling on neurite growth and axonal pathfinding. In our model, cell-autonomus and paracrine eCBs acting on CB1Rs are part of a global inhibitory network of cytoskeletal effectors, which act in concert with positive-feedback local-excitation loops, to ultimately yield highly polarized neurons.
Collapse
Affiliation(s)
- Anne-Lise Gaffuri
- Neurobiology Laboratory, ESPCI-ParisTech, ESPCI-CNRS UMR 7637, Paris, France
| | | | | |
Collapse
|
39
|
Stabilized G protein binding site in the structure of constitutively active metarhodopsin-II. Proc Natl Acad Sci U S A 2011; 109:119-24. [PMID: 22198838 DOI: 10.1073/pnas.1114089108] [Citation(s) in RCA: 188] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
G protein-coupled receptors (GPCR) are seven transmembrane helix proteins that couple binding of extracellular ligands to conformational changes and activation of intracellular G proteins, GPCR kinases, and arrestins. Constitutively active mutants are ubiquitously found among GPCRs and increase the inherent basal activity of the receptor, which often correlates with a pathological outcome. Here, we have used the M257Y(6.40) constitutively active mutant of the photoreceptor rhodopsin in combination with the specific binding of a C-terminal fragment from the G protein alpha subunit (GαCT) to trap a light activated state for crystallization. The structure of the M257Y/GαCT complex contains the agonist all-trans-retinal covalently bound to the native binding pocket and resembles the G protein binding metarhodopsin-II conformation obtained by the natural activation mechanism; i.e., illumination of the prebound chromophore 11-cis-retinal. The structure further suggests a molecular basis for the constitutive activity of 6.40 substitutions and the strong effect of the introduced tyrosine based on specific interactions with Y223(5.58) in helix 5, Y306(7.53) of the NPxxY motif and R135(3.50) of the E(D)RY motif, highly conserved residues of the G protein binding site.
Collapse
|
40
|
Fanelli F, De Benedetti PG. Update 1 of: computational modeling approaches to structure-function analysis of G protein-coupled receptors. Chem Rev 2011; 111:PR438-535. [PMID: 22165845 DOI: 10.1021/cr100437t] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Francesca Fanelli
- Dulbecco Telethon Institute, University of Modena and Reggio Emilia, via Campi 183, 41125 Modena, Italy.
| | | |
Collapse
|
41
|
Hulme EC, Lu ZL, Bee MS. Scanning Mutagenesis Studies of the M 1 Muscarinic Acetylcholine Receptor. ACTA ACUST UNITED AC 2011. [DOI: 10.3109/10606820308261] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
42
|
Sabatino D, Proulx C, Pohankova P, Ong H, Lubell WD. Structure–Activity Relationships of GHRP-6 Azapeptide Ligands of the CD36 Scavenger Receptor by Solid-Phase Submonomer Azapeptide Synthesis. J Am Chem Soc 2011; 133:12493-506. [DOI: 10.1021/ja203007u] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David Sabatino
- Department of Chemistry and Biochemistry, Seton Hall University, 400 South Orange Avenue, South Orange New Jersey 07079, United States
| | | | | | | | | |
Collapse
|
43
|
Grossfield A. Recent progress in the study of G protein-coupled receptors with molecular dynamics computer simulations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1868-78. [DOI: 10.1016/j.bbamem.2011.03.010] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 02/23/2011] [Accepted: 03/21/2011] [Indexed: 01/28/2023]
|
44
|
Allen JA, Roth BL. Strategies to discover unexpected targets for drugs active at G protein-coupled receptors. Annu Rev Pharmacol Toxicol 2011; 51:117-44. [PMID: 20868273 DOI: 10.1146/annurev-pharmtox-010510-100553] [Citation(s) in RCA: 163] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
G protein-coupled receptors (GPCRs) are an evolutionarily conserved family of signaling molecules comprising approximately 2% of the human genome; this receptor family remains a central focus in basic pharmacology studies and drug discovery efforts. Detailed studies of drug action at GPCRs over the past decade have revealed existing and novel ligands that exhibit polypharmacology-that is, drugs with activity at more than one receptor target for which they were designed. These "off-target" drug actions can be a liability that causes adverse side effects; however, in several cases, drugs with less selectivity demonstrate better clinical efficacy. Here we review physical screening and cheminformatic approaches that define drug activity at the GPCR receptorome. In many cases, such profiling has revealed unexpected targets that explain therapeutic actions as well as off-targets underlying drug side effects. Such drug-receptor profiling has also provided new insights into mechanisms of action of existing drugs and has suggested directions for future drug development.
Collapse
Affiliation(s)
- John A Allen
- Department of Pharmacology, University of North Carolina, Chapel Hill, 27599, USA
| | | |
Collapse
|
45
|
Kim SK, Li Y, Abrol R, Heo J, Goddard WA. Predicted structures and dynamics for agonists and antagonists bound to serotonin 5-HT2B and 5-HT2C receptors. J Chem Inf Model 2011; 51:420-33. [PMID: 21299232 DOI: 10.1021/ci100375b] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Subtype 2 serotonin (5-hydroxytryptamine, 5-HT) receptors are major drug targets for schizophrenia, feeding disorders, perception, depression, migraines, hypertension, anxiety, hallucinogens, and gastrointestinal dysfunctions. (1) We report here the predicted structure of 5-HT2B and 5-HT2C receptors bound to highly potent and selective 5-HT2B antagonist PRX-08066 3, (pKi: 30 nM), including the key binding residues [V103 (2.53), L132 (3.29), V190 (4.60), and L347 (6.58)] determining the selectivity of binding to 5-HT2B over 5-HT2A. We also report structures of the endogenous agonist (5-HT) and a HT2B selective antagonist 2 (1-methyl-1-1,6,7,8-tetrahydro-pyrrolo[2,3-g]quinoline-5-carboxylic acid pyridine-3-ylamide). We examine the dynamics for the agonist- and antagonist-bound HT2B receptors in explicit membrane and water finding dramatically different patterns of water migration into the NPxxY motif and the binding site that correlates with the stability of ionic locks in the D(E)RY region.
Collapse
Affiliation(s)
- Soo-Kyung Kim
- Materials and Process Simulation Center, California Institute of Technology, Pasadena, California 91125, USA
| | | | | | | | | |
Collapse
|
46
|
Abstract
G protein-coupled receptors (GPCRs) comprise a large class of transmembrane proteins that play critical roles in both normal physiology and pathophysiology. These critical roles offer targets for therapeutic intervention, as exemplified by the substantial fraction of current pharmaceutical agents that target members of this family. Tremendous contributions to our understanding of GPCR structure and dynamics have come from both indirect and direct structural characterization techniques. Key features of GPCR conformations derived from both types of characterization techniques are reviewed.
Collapse
Affiliation(s)
- Abby L. Parrill
- Department of Chemistry, The University of Memphis, Memphis, TN 38152, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-901-678-2638; Fax: +1-901-678-3447
| | - Debra L. Bautista
- Christian Brothers High School, 5900 Walnut Grove Road, Memphis, TN 38120, USA; E-Mail: (D.L.B.)
| |
Collapse
|
47
|
Nikiforovich GV, Marshall GR, Baranski TJ. Simplified modeling approach suggests structural mechanisms for constitutive activation of the C5a receptor. Proteins 2010; 79:787-802. [PMID: 21287612 DOI: 10.1002/prot.22918] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 10/11/2010] [Accepted: 10/13/2010] [Indexed: 11/07/2022]
Abstract
Molecular modeling of conformational changes occurring in the transmembrane region of the complement factor 5a receptor (C5aR) during receptor activation was performed by comparing two constitutively active mutants (CAMs) of C5aR, NQ (I124N/L127Q), and F251A, to those of the wild-type C5aR and NQ-N296A (I124N/L127Q/N296A), which have the wild-type phenotype. Modeling involved comprehensive sampling of various rotations of TM helices aligned to the crystal template of the dark-adapted rhodopsin along their long axes. By assuming that the relative energies of the spontaneously activated states of CAMs should be lower or at least comparable to energies characteristic for the ground states, we selected the plausible models for the conformational states associated with constitutive activation in C5aR. The modeling revealed that the hydrogen bonds between the side chains of D82-N119, S85-N119, and S131-C221 characteristic for the ground state were replaced by the hydrogen bonds D82-N296, N296-Y300, and S131-R134, respectively, in the activated states. Also, conformational transitions that occurred upon activation were hindered by contacts between the side chains of L127 and F251. The results rationalize the available data of mutagenesis in C5aR and offer the first specific molecular mechanism for the loss of constitutive activity in NQ-N296A. Our results also contributed to understanding the general structural mechanisms of activation in G-protein-coupled receptors lacking the "ionic lock", R(3.50) and E/D(6.30). Importantly, these results were obtained by modeling approaches that deliberately simplify many elements in order to explore potential conformations of GPCRs involving large-scale molecular movements.
Collapse
|
48
|
López L, Selent J, Ortega R, Masaguer CF, Domínguez E, Areias F, Brea J, Loza MI, Sanz F, Pastor M. Synthesis, 3D-QSAR, and structural modeling of benzolactam derivatives with binding affinity for the D(2) and D(3) receptors. ChemMedChem 2010; 5:1300-17. [PMID: 20544783 DOI: 10.1002/cmdc.201000101] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A series of 37 benzolactam derivatives were synthesized, and their respective affinities for the dopamine D(2) and D(3) receptors evaluated. The relationships between structures and binding affinities were investigated using both ligand-based (3D-QSAR) and receptor-based methods. The results revealed the importance of diverse structural features in explaining the differences in the observed affinities, such as the location of the benzolactam carbonyl oxygen, or the overall length of the compounds. The optimal values for such ligand properties are slightly different for the D(2) and D(3) receptors, even though the binding sites present a very high degree of homology. We explain these differences by the presence of a hydrogen bond network in the D(2) receptor which is absent in the D(3) receptor and limits the dimensions of the binding pocket, causing residues in helix 7 to become less accessible. The implications of these results for the design of more potent and selective benzolactam derivatives are presented and discussed.
Collapse
Affiliation(s)
- Laura López
- GRIB, IMIM, DCEXS, Universitat Pompeu Fabra, Barcelona, Spain
| | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
An evolutionarily conserved arginine is essential for Tre1 G protein-coupled receptor function during germ cell migration in Drosophila melanogaster. PLoS One 2010; 5:e11839. [PMID: 20676220 PMCID: PMC2911388 DOI: 10.1371/journal.pone.0011839] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Accepted: 06/29/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND G protein-coupled receptors (GPCRs) play central roles in mediating cellular responses to environmental signals leading to changes in cell physiology and behaviors, including cell migration. Numerous clinical pathologies including metastasis, an invasive form of cell migration, have been linked to abnormal GPCR signaling. While the structures of some GPCRs have been defined, the in vivo roles of conserved amino acid residues and their relationships to receptor function are not fully understood. Trapped in endoderm 1 (Tre1) is an orphan receptor of the rhodopsin class that is necessary for primordial germ cell migration in Drosophila melanogaster embryos. In this study, we employ molecular genetic approaches to identify residues in Tre1 that are critical to its functions in germ cell migration. METHODOLOGY/PRINCIPAL FINDINGS First, we show that the previously reported scattershot mutation is an allele of tre1. The scattershot allele results in an in-frame deletion of 8 amino acids at the junction of the third transmembrane domain and the second intracellular loop of Tre1 that dramatically impairs the function of this GPCR in germ cell migration. To further refine the molecular basis for this phenotype, we assayed the effects of single amino acid substitutions in transgenic animals and determined that the arginine within the evolutionarily conserved E/N/DRY motif is critical for receptor function in mediating germ cell migration within an intact developing embryo. CONCLUSIONS/SIGNIFICANCE These structure-function studies of GPCR signaling in native contexts will inform future studies into the basic biology of this large and clinically important family of receptors.
Collapse
|
50
|
Varin T, Gutiérrez-de-Terán H, Castro M, Brea J, Fabis F, Dauphin F, Åqvist J, Lepailleur A, Perez P, Burgueño J, Vela JM, Loza MI, Rodrigo J. Phe369(7.38) at human 5-HT(7) receptors confers interspecies selectivity to antagonists and partial agonists. Br J Pharmacol 2010; 159:1069-81. [PMID: 19922537 PMCID: PMC2839265 DOI: 10.1111/j.1476-5381.2009.00481.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2009] [Revised: 07/22/2009] [Accepted: 07/31/2009] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Human and rat 5-HT(7) receptors were studied with a particular emphasis on the molecular interactions involved in ligand binding, searching for an explanation to the interspecies selectivity observed for a set of compounds. We performed affinity studies, molecular modelling and site-directed mutagenesis, with special focus on residue Phe(7.38) of the human 5-HT(7) receptor [Cys(7.38) in rat]. EXPERIMENTAL APPROACH Competition binding studies were performed for seven 5-HT(7) receptor ligands at three different 5-HT(7) receptors. The functional behaviour was evaluated by measuring 5-carboxytryptamine-stimulated cAMP production. Computational simulations were carried out to explore the structural bases in ligand binding observed for these compounds. KEY RESULTS Competition experiments showed a remarkable selectivity for the human receptor when compared with the rat receptor. These results indicate that mutating Cys to Phe at position 7.38 profoundly affects the binding affinities at the 5-HT(7) receptor. Computational simulations provide a structural interpretation for this key finding. Pharmacological characterization of compounds mr25020, mr25040 and mr25053 revealed a competitive antagonistic behaviour. Compounds mr22423, mr22433, mr23284 and mr25052 behaved as partial agonists. CONCLUSIONS AND IMPLICATIONS We propose that the interspecies difference in binding affinities observed for the compounds at human and rat 5-HT(7) receptors is due to the nature of the residue at position 7.38. Our molecular modelling simulations suggest that Phe(7.38) in the human receptor is integrated in the hydrophobic pocket in the central part of the binding site [Phe(6.51)-Phe(6.52)] and allows a tighter binding of the ligands when compared with the rat receptor.
Collapse
Affiliation(s)
- Thibault Varin
- Centre d'Etudes et de Recherche sur le Médicament de Normandie (CERMN), UFR des Sciences Pharmaceutiques, Université de Caen Basse-NormandieCaen, France
| | - Hugo Gutiérrez-de-Terán
- Fundación Pública Galega de Medicina Xenómica, Hospital Clínico Universitario de SantiagoSantiago de Compostela, Spain
| | - Marián Castro
- BioFarma Research Group, Departamento de Farmacoloxia, Facultade de Farmacia, Instituto de Farmacia Industrial, Universidade de Santiago de CompostelaSantiago de Compostela, Spain
| | - José Brea
- BioFarma Research Group, Departamento de Farmacoloxia, Facultade de Farmacia, Instituto de Farmacia Industrial, Universidade de Santiago de CompostelaSantiago de Compostela, Spain
| | - Frederic Fabis
- Centre d'Etudes et de Recherche sur le Médicament de Normandie (CERMN), UFR des Sciences Pharmaceutiques, Université de Caen Basse-NormandieCaen, France
| | - François Dauphin
- Centre d'Etudes et de Recherche sur le Médicament de Normandie (CERMN), UFR des Sciences Pharmaceutiques, Université de Caen Basse-NormandieCaen, France
| | - Johan Åqvist
- Department of Cell and Molecular Biology, Uppsala UniversityUppsala, Sweden
| | - Alban Lepailleur
- Centre d'Etudes et de Recherche sur le Médicament de Normandie (CERMN), UFR des Sciences Pharmaceutiques, Université de Caen Basse-NormandieCaen, France
| | - Pilar Perez
- Department of Pharmacology, Laboratorios EsteveBarcelona, Spain
| | - Javier Burgueño
- Department of Pharmacology, Laboratorios EsteveBarcelona, Spain
| | | | - Maria Isabel Loza
- BioFarma Research Group, Departamento de Farmacoloxia, Facultade de Farmacia, Instituto de Farmacia Industrial, Universidade de Santiago de CompostelaSantiago de Compostela, Spain
| | - Jordi Rodrigo
- Centre d'Etudes et de Recherche sur le Médicament de Normandie (CERMN), UFR des Sciences Pharmaceutiques, Université de Caen Basse-NormandieCaen, France
| |
Collapse
|