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Odoemelam CS, Percival B, Wallis H, Chang MW, Ahmad Z, Scholey D, Burton E, Williams IH, Kamerlin CL, Wilson PB. G-Protein coupled receptors: structure and function in drug discovery. RSC Adv 2020; 10:36337-36348. [PMID: 35517958 PMCID: PMC9057076 DOI: 10.1039/d0ra08003a] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022] Open
Abstract
The G-protein coupled receptors (GPCRs) superfamily comprise similar proteins arranged into families or classes thus making it one of the largest in the mammalian genome. GPCRs take part in many vital physiological functions making them targets for numerous novel drugs. GPCRs share some distinctive features, such as the seven transmembrane domains, they also differ in the number of conserved residues in their transmembrane domain. Here we provide an introductory and accessible review detailing the computational advances in GPCR pharmacology and drug discovery. An overview is provided on family A-C GPCRs; their structural differences, GPCR signalling, allosteric binding and cooperativity. The dielectric constant (relative permittivity) of proteins is also discussed in the context of site-specific environmental effects.
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Affiliation(s)
| | - Benita Percival
- Nottingham Trent University 50 Shakespeare St Nottingham NG1 4FQ UK
| | - Helen Wallis
- Nottingham Trent University 50 Shakespeare St Nottingham NG1 4FQ UK
| | - Ming-Wei Chang
- Nanotechnology and Integrated Bioengineering Centre, University of Ulster Jordanstown Campus Newtownabbey BT37 0QB Northern Ireland UK
| | - Zeeshan Ahmad
- De Montfort University The Gateway Leicester LE1 9BH UK
| | - Dawn Scholey
- Nottingham Trent University 50 Shakespeare St Nottingham NG1 4FQ UK
| | - Emily Burton
- Nottingham Trent University 50 Shakespeare St Nottingham NG1 4FQ UK
| | - Ian H Williams
- Department of Chemistry, University of Bath Claverton Down Bath BA1 7AY UK
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Pandey A, LeBlanc DM, Parmar HB, Phạm TTT, Sarker M, Xu L, Duncan R, Liu XQ, Rainey JK. Structure, amphipathy, and topology of the membrane-proximal helix 8 influence apelin receptor plasma membrane localization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:183036. [PMID: 31394100 DOI: 10.1016/j.bbamem.2019.183036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 07/08/2019] [Accepted: 08/02/2019] [Indexed: 12/11/2022]
Abstract
G-protein coupled receptors (GPCRs) typically have an amphipathic helix ("helix 8") immediately C-terminal to the transmembrane helical bundle. To date, a number of functional roles have been associated with GPCR helix 8 segments, but structure-function analysis for this region remains limited. Here, we examine helix 8 of the apelin receptor (AR or APJ), a class A GPCR with wide physiological and pathophysiological relevance. The 71 residue C-terminal tail of the AR is primarily intrinsically disordered, with a detergent micelle-induced increase in helical character. This helicity was localized to the helix 8 region, in good agreement with the recent AR crystal structure. A series of helix 8 mutants were made to reduce helicity, remove amphipathy, or flip the hydrophobic and hydrophilic faces. Each mutant AR was tested both biophysically, in the isolated C-terminal tail, and functionally in HEK 293 T cells, for full-length AR. In all instances, micelle interactions were maintained, and steady-state AR expression was efficient. However, removal of amphipathy or helical character led to a significant decrease in cell surface localization. Flipping of helix 8 amphipathic topology restored cell surface localization to some degree, but still was significantly reduced relative to wild-type. Structural integrity, amphipathy to drive membrane association, and correct topology of helix 8 membrane association all thus appear important for cell surface localization of the AR. This behavior correlates well to GPCR C-terminal tail sequence motifs, implying that these serve to specify key topological features of helix 8 and its proximity to the transmembrane domain.
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Affiliation(s)
- Aditya Pandey
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Danielle M LeBlanc
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Hirendrasinh B Parmar
- Department of Microbiology & Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Trần Thanh Tâm Phạm
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Muzaddid Sarker
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Microbiology & Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Lingling Xu
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Roy Duncan
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Microbiology & Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Xiang-Qin Liu
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Jan K Rainey
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
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Abstract
Substance P (SP) is an important mediator of pro-inflammatory mechanisms in the skin. It targets multiple cells such as keratinocytes, mast cells, and fibroblasts which are involved in the cutaneous generation of pruritus. This suggests that SP is an interesting target for therapy. In fact, in recent case reports and case series, SP antagonists demonstrated a significant antipruritic effect in acute and chronic pruritus such as drug-induced pruritus, paraneoplastic pruritus, prurigo nodularis, cutaneous T-cell lymphoma, and brachioradial pruritus.
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Affiliation(s)
- Sonja Ständer
- Department of Dermatology, Competence Center Chronic Pruritus, University Hospital of Münster, Von-Esmarch-Strasse 58, 48149, Münster, Germany,
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Spomer L, Gertzen CGW, Schmitz B, Häussinger D, Gohlke H, Keitel V. A membrane-proximal, C-terminal α-helix is required for plasma membrane localization and function of the G Protein-coupled receptor (GPCR) TGR5. J Biol Chem 2013; 289:3689-702. [PMID: 24338481 DOI: 10.1074/jbc.m113.502344] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The C terminus of G protein-coupled receptors (GPCRs) is important for G protein-coupling and activation; in addition, sorting motifs have been identified in the C termini of several GPCRs that facilitate correct trafficking from the endoplasmic reticulum to the plasma membrane. The C terminus of the GPCR TGR5 lacks any known sorting motif such that other factors must determine its trafficking. Here, we investigate deletion and substitution variants of the membrane-proximal C terminus of TGR5 with respect to plasma membrane localization and function using immunofluorescence staining, flow cytometry, and luciferase assays. Peptides of the membrane-proximal C-terminal variants are subjected to molecular dynamics simulations and analyzed with respect to their secondary structure. Our results reveal that TGR5 plasma membrane localization and responsiveness to extracellular ligands is fostered by a long (≥ 9 residues) α-helical stretch at the C terminus, whereas the presence of β-strands or only a short α-helical stretch leads to retention in the endoplasmic reticulum and a loss of function. As a proof-of-principle, chimeras of TGR5 containing the membrane-proximal amino acids of the β2 adrenergic receptor (β2AR), the sphingosine 1-phosphate receptor-1 (S1P1), or the κ-type opioid receptor (κOR) were generated. These TGR5β2AR, TGR5S1P1, or TGR5κOR chimeras were correctly sorted to the plasma membrane. As the exchanged amino acids of the β2AR, the S1P1, or the κOR form α-helices in crystal structures but lack significant sequence identity to the respective TGR5 sequence, we conclude that the secondary structure of the TGR5 membrane-proximal C terminus is the determining factor for plasma membrane localization and responsiveness towards extracellular ligands.
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Affiliation(s)
- Lina Spomer
- From the Clinic for Gastroenterology, Hepatology, and Infectious Diseases and
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