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Cha HJ, Lee H, Yeo EJ, Yeo HJ, Choi YJ, Sohn EJ, Kim DW, Park SJ, Lee SH, Lee S, Choi SY. Utilization of an Intracellular Calcium Mobilization Assay for the Screening of Transduced FK506-Binding Proteins. Assay Drug Dev Technol 2021; 19:442-452. [PMID: 34415786 DOI: 10.1089/adt.2021.065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
FK506-binding proteins (FKBPs) belong to the immunophilin family and are linked to various disease states, including the inflammatory response. The inhibition of cytokine and chemokine expression in addition to positive effects of FKBPs on corneal inflammation in animal models suggests that they may be used for ophthalmic delivery in the treatment of dry eye disease. To pass the effective barriers protecting eye tissues, testing the transduction domains of FKBPs is essential. However, monitoring their transduction efficiencies is not a simple task. The quantitative measurement of FKBP interactions was performed using a cell model with a specific G protein-coupled receptor, as FKBPs had been known to act at the inositol 1,4,5-trisphosphate receptor (IP3R) leading to the inhibition of intracellular calcium mobilization. Because of its luminescence amplitude and stability, human urotensin II receptor was expressed in aequorin parental cells to measure the action of selected FKBPs. This luminescence-based functional assay platform exhibited a high signal-to-background ratio of more than 100 and a Z' factor at 0.6204. As expected, changes in the sequence of the transduction domain affected the function of the FKBPs. The intracellular calcium mobilization assay with selected FKBPs represented a robust and reliable platform to screen initial candidates. Although the precise nature of the control that FKBPs exert on the IP3R is uncertain, this approach can be used to develop innovative anti-inflammatory treatments for dry eye disease by optimizing protein transduction domain sequences.
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Affiliation(s)
- Hyun Ju Cha
- R&D Center, Lumieye Genetics Co., Ltd., Seoul, Korea
| | - Hyunjin Lee
- Department of Green Chemical Engineering, Sangmyung University, Cheonan, Korea
| | - Eun Ji Yeo
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, Korea
| | - Hyeon Ji Yeo
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, Korea
| | - Yeon Joo Choi
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, Korea
| | - Eun Jeong Sohn
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, Korea
| | - Dae Won Kim
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung-Wonju National University, Gangneung, Korea
| | - Soo Jung Park
- R&D Center, Lumieye Genetics Co., Ltd., Seoul, Korea
| | - Sung Ho Lee
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, Korea
| | - Sunghou Lee
- Department of Green Chemical Engineering, Sangmyung University, Cheonan, Korea
| | - Soo Young Choi
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, Korea
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Ichiyama S, Nemoto R, Tanabe H, Haga T. Interaction of the muscarinic acetylcholine receptor M₂ subtype with G protein Gα(i/o) isotypes and Gβγ subunits as studied with the maltose-binding protein-M₂-Gα(i/o) fusion proteins expressed in Escherichia coli. J Biochem 2014; 156:259-72. [PMID: 24881046 DOI: 10.1093/jb/mvu036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We expressed the fusion proteins of the muscarinic acetylcholine receptor M2 subtype (M2 receptor) with a maltose-binding protein (MBP) and various G protein α subunits (Gα(i1-i3/o)) at its N- and C-terminals, respectively (MBP-M2-Gα(i/o)), in Escherichia coli, and examined the effect of G protein βγ subunits (Gβγ) on the receptor-Gα interaction as assessed by agonist- and GDP-dependent [(35)S]GTPγS binding of the fusion proteins. We found that (i) Gβγ promoted both the agonist-dependent and -independent [(35)S]GTPγS binding with little effect on the guanine nucleotide-sensitive high-affinity agonist binding, (ii) the specific [(35)S]GTPγS binding activity was much greater for MBP-M2-Gα(oA) than for MBP-M2-Gα(i1-i3) in the absence of Gβγ, whereas Gβγ preferentially promoted the agonist-dependent decrease in the affinity for GDP of MBP-M2-Gα(i1-i3) rather than of MBP-M2-Gα(oA), and (iii) the proportion of agonist-dependent [(35)S]GTPγS binding was roughly 50% irrespective of species of Gα and the presence or absence of Gβγ. These results demonstrate that receptor-Gα fusion proteins expressed in E. coli could be useful for studies of receptor-G interaction.
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Affiliation(s)
- Susumu Ichiyama
- Faculty of Science, Institute for Biomolecular Science, Gakushuin University, 1-5-1 Mejiro, Toshima-Ku, Tokyo 171-8588, Japan
| | - Reiko Nemoto
- Faculty of Science, Institute for Biomolecular Science, Gakushuin University, 1-5-1 Mejiro, Toshima-Ku, Tokyo 171-8588, Japan
| | - Hiroaki Tanabe
- Faculty of Science, Institute for Biomolecular Science, Gakushuin University, 1-5-1 Mejiro, Toshima-Ku, Tokyo 171-8588, Japan
| | - Tatsuya Haga
- Faculty of Science, Institute for Biomolecular Science, Gakushuin University, 1-5-1 Mejiro, Toshima-Ku, Tokyo 171-8588, Japan
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Fujita M, Takada YK, Takada Y. The chemokine fractalkine can activate integrins without CX3CR1 through direct binding to a ligand-binding site distinct from the classical RGD-binding site. PLoS One 2014; 9:e96372. [PMID: 24789099 PMCID: PMC4008574 DOI: 10.1371/journal.pone.0096372] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 04/07/2014] [Indexed: 11/19/2022] Open
Abstract
The chemokine domain of fractalkine (FKN-CD) binds to the classical RGD-binding site of αvβ3 and that the resulting ternary complex formation (integrin-FKN-CX3CR1) is critical for CX3CR1 signaling and FKN-induced integrin activation. However, only certain cell types express CX3CR1. Here we studied if FKN-CD can activate integrins in the absence of CX3CR1. We describe that WT FKN-CD activated recombinant soluble αvβ3 in cell-free conditions, but the integrin-binding defective mutant of FKN-CD (K36E/R37E) did not. This suggests that FKN-CD can activate αvβ3 in the absence of CX3CR1 through the direct binding of FKN-CD to αvβ3. WT FKN-CD activated αvβ3 on CX3CR1-negative cells (K562 and CHO) but K36E/R37E did not, suggesting that FKN-CD can activate integrin at the cellular levels in a manner similar to that in cell-free conditions. We hypothesized that FKN-CD enhances ligand binding to the classical RGD-binding site (site 1) through binding to a second binding site (site 2) that is distinct from site 1 in αvβ3. To identify the possible second FKN-CD binding site we performed docking simulation of αvβ3-FKN-CD interaction using αvβ3 with a closed inactive conformation as a target. The simulation predicted a potential FKN-CD-binding site in inactive αvβ3 (site 2), which is located at a crevice between αv and β3 on the opposite side of site 1 in the αvβ3 headpiece. We studied if FKN-CD really binds to site 2 using a peptide that is predicted to interact with FKN-CD in site 2. Notably the peptide specifically bound to FKN-CD and effectively suppressed integrin activation by FKN-CD. This suggests that FKN-CD actually binds to site 2, and this leads to integrin activation. We obtained very similar results in α4β1 and α5β1. The FKN binding to site 2 and resulting integrin activation may be a novel mechanism of integrin activation and of FKN signaling.
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Affiliation(s)
- Masaaki Fujita
- Department of Dermatology, Biochemistry and Molecular Medicine, UC Davis School of Medicine, Sacramento, California, United States of America
| | - Yoko K. Takada
- Department of Dermatology, Biochemistry and Molecular Medicine, UC Davis School of Medicine, Sacramento, California, United States of America
| | - Yoshikazu Takada
- Department of Dermatology, Biochemistry and Molecular Medicine, UC Davis School of Medicine, Sacramento, California, United States of America
- * E-mail:
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Ma AWS, Dong JY, Ma D, Wells JW. Cleavage-resistant fusion proteins of the M(2) muscarinic receptor and Gα(i1). Homotropic and heterotropic effects in the binding of ligands. Biochim Biophys Acta Gen Subj 2011; 1810:592-602. [PMID: 21397664 DOI: 10.1016/j.bbagen.2011.03.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 01/28/2011] [Accepted: 03/02/2011] [Indexed: 11/30/2022]
Abstract
BACKGROUND G protein-coupled receptors fused to a Gα-subunit are functionally similar to their unfused counterparts. They offer an intriguing view into the nature of the receptor-G protein complex, but their usefulness depends upon the stability of the fusion. METHODS Fusion proteins of the M(2) muscarinic receptor and the α-subunit of G(i1) were expressed in CHO and Sf9 cells, extracted in digitonin-cholate, and examined for their binding properties and their electrophoretic mobility on western blots. RESULTS Receptor fused to native α(i1) underwent proteolysis near the point of fusion to release a fragment with the mobility of α(i1). The cleavage was prevented by truncation of the α-subunit at position 18. Binding of the agonist oxotremorine-M to the stable fusion protein from Sf9 cells was biphasic, and guanylylimidodiphosphate promoted an apparent interconversion of sites from higher to lower affinity. With receptor from CHO cells, the apparent capacity for N-[(3)H]methylscopolamine was 60% of that for [(3)H]quinuclidinylbenzilate; binding at saturating concentrations of the latter was inhibited in a noncompetitive manner at low concentrations of unlabeled N-methylscopolamine. CONCLUSIONS A stable fusion protein of the M(2) receptor and truncated α(i1) resembles the native receptor-G protein complex with respect to the guanyl nucleotide-sensitive binding of agonists and the noncompetitive binding of antagonists. GENERAL SIGNIFICANCE Release of the α-subunit is likely to occur with other such fusion proteins, rendering the data ambiguous or misleading. The properties of a chemically stable fusion protein support the notion that signaling proceeds via a stable multimeric complex of receptor and G protein.
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Affiliation(s)
- Amy W-S Ma
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada
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Tabata KI, Baba K, Shiraishi A, Ito M, Fujita N. The orphan GPCR GPR87 was deorphanized and shown to be a lysophosphatidic acid receptor. Biochem Biophys Res Commun 2007; 363:861-6. [PMID: 17905198 DOI: 10.1016/j.bbrc.2007.09.063] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Accepted: 09/13/2007] [Indexed: 12/31/2022]
Abstract
In CHO cells stably expressing the GPR87 fused with a G16alpha protein, lysophosphatidic acid (LPA) evoked an intracellular Ca(2+) increase in a high affinity manner. The Ca(2+) increase was reversibly blocked by the LPA receptor antagonists and inhibited by pretreatment of the cells with GPR87-specific siRNAs. GPR87 was shown to be closer to the P2Y and P2Y-related receptors than LPA receptors by ClustalW analyses. However, none of nucleotides and their derivatives activated GPR87. The human gpr87 is located on the chromosome 3q25 in a cluster containing p2y12,13,14. RT-PCR analysis showed that the mouse GPR87 was expressed in placenta, ovary, testis, prostate, brain, and skeletal muscle. The 3D model of GPR87-LPA complex indicated that the ligand interacted with R115 and K296 of GPR87, which are well conserved in the P2Y receptors. These results suggest that the GPR87 is a LPA receptor which evolved from a common ancestor of P2Y receptors.
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MESH Headings
- Animals
- Binding Sites/genetics
- CHO Cells
- Calcium/metabolism
- Cricetinae
- Cricetulus
- Electrophoresis, Polyacrylamide Gel
- Female
- GTP-Binding Protein alpha Subunits/genetics
- GTP-Binding Protein alpha Subunits/metabolism
- Gene Expression Profiling
- Humans
- Intracellular Fluid/drug effects
- Intracellular Fluid/metabolism
- Isoxazoles/pharmacology
- Lysophospholipids/metabolism
- Lysophospholipids/pharmacology
- Male
- Mice
- Mice, Inbred BALB C
- Models, Molecular
- Propionates/pharmacology
- Protein Structure, Tertiary
- RNA Interference
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Lysophosphatidic Acid/antagonists & inhibitors
- Receptors, Lysophosphatidic Acid/genetics
- Receptors, Lysophosphatidic Acid/metabolism
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Uridine Triphosphate/pharmacology
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Affiliation(s)
- Ken-ichi Tabata
- Laboratory of Pharmcoinformatics, Department of Bioscience and Bioinformatics, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
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Suga H, Haga T. Ligand screening system using fusion proteins of G protein-coupled receptors with G protein alpha subunits. Neurochem Int 2007; 51:140-64. [PMID: 17659814 DOI: 10.1016/j.neuint.2007.06.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2007] [Revised: 06/07/2007] [Accepted: 06/08/2007] [Indexed: 01/04/2023]
Abstract
G protein-coupled receptors (GPCRs) constitute one of the largest families of genes in the human genome, and are the largest targets for drug development. Although a large number of GPCR genes have recently been identified, ligands have not yet been identified for many of them. Various assay systems have been employed to identify ligands for orphan GPCRs, but there is still no simple and general method to screen for ligands of such GPCRs, particularly of G(i)-coupled receptors. We have examined whether fusion proteins of GPCRs with G protein alpha subunit (Galpha) could be utilized for ligand screening and showed that the fusion proteins provide an effective method for the purpose. This article focuses on the followings: (1) characterization of GPCR genes and GPCRs, (2) identification of ligands for orphan GPCRs, (3) characterization of GPCR-Galpha fusion proteins, and (4) identification of ligands for orphan GPCRs using GPCR-Galpha fusion proteins.
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Affiliation(s)
- Hinako Suga
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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Nonaka Y, Hiramoto T, Fujita N. Identification of endogenous surrogate ligands for human P2Y12 receptors by in silico and in vitro methods. Biochem Biophys Res Commun 2005; 337:281-8. [PMID: 16185654 DOI: 10.1016/j.bbrc.2005.09.052] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Accepted: 09/09/2005] [Indexed: 10/25/2022]
Abstract
Endogenous ligands acting on a human P2Y12 receptor, one of the G-protein coupled receptors, were searched by in silico screening against our own database, which contains more than 500 animal metabolites. The in silico screening using the docking software AutoDock resulted in selection of cysteinylleukotrienes (CysLTs) and 5-phosphoribosyl 1-pyrophosphate (PRPP), with high free energy changes, in addition to the known P2Y12 ligands such as 2MeSADP and ADP. These candidates were subjected to an in vitro Ca2+ assay using the CHO cells stably expressing P2Y12-G16alpha fusion proteins. We found that CysLTE4 and PRPP acted on the P2Y12 receptor as agonists with the EC50 values of 1.3 and 7.8 nM, respectively. Furthermore, we analyzed the phylogenetic relationship of the P2Y, P2Y-like, and CysLT receptors based on sequence alignment followed by evolutionary analyses. The analyses showed that the P2Y12, P2Y13, P2Y14, GPR87, CysLT-1, and CysLT-2 receptors formed a P2Y-related receptor subfamily with common sequence motifs in the transmembrane regions.
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Affiliation(s)
- Yosuke Nonaka
- Laboratory of Pharmcoinformatics, Department of Bioinformatics, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
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