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Ihara M, Hikida M, Matsushita H, Yamanaka K, Kishimoto Y, Kubo K, Watanabe S, Sakamoto M, Matsui K, Yamaguchi A, Okuhara D, Furutani S, Sattelle DB, Matsuda K. Loops D, E and G in the Drosophila Dα1 subunit contribute to high neonicotinoid sensitivity of Dα1-chicken β2 nicotinic acetylcholine receptor. Br J Pharmacol 2017; 175:1999-2012. [PMID: 28616862 DOI: 10.1111/bph.13914] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 05/02/2017] [Accepted: 06/05/2017] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND AND PURPOSE Neonicotinoid insecticides interact with the orthosteric site formed at subunit interfaces of insect nicotinic ACh (nACh) receptors. However, their interactions with the orthosteric sites at α-non α and α-α subunit interfaces remain poorly understood. The aim of this study was to elucidate the mechanism of neonicotinoid actions using the Drosophila Dα1-chicken β2 hybrid nACh receptor. EXPERIMENTAL APPROACH Computer models of the (Dα1)3 (β2)2 nACh receptor in complex with imidacloprid and thiacloprid were generated. Amino acids in the Dα1 subunit were mutated to corresponding amino acids in the human α4 subunit to examine their effects on the agonist actions of neonicotinoids on (Dα1)3 (β2)2 and (Dα1)2 (β2)3 nACh receptors expressed in Xenopus laevis oocytes using voltage-clamp electrophysiology. KEY RESULTS The (Dα1)3 (β2)2 nACh receptor models indicated that amino acids in loops D, E and G probably determine the effects of neonicotinoids. The amino acid mutations tested had minimal effects on the EC50 for ACh. However, the R57S mutation in loop G, although having minimal effect on imidacloprid's actions, reduced the affinity of thiacloprid for the (Dα1)3 (β2)2 nACh receptor, while scarcely affecting thiacloprid's action on the (Dα1)2 (β2)3 nACh receptor. Both the K140T and the combined R57S;K140T mutations reduced neonicotinoid efficacy but only for the (Dα1)3 (β2)2 nACh receptor. Combining the E78K mutation with the R57S;K140T mutations resulted in a selective reduction of thiacloprid's affinity for the (Dα1)3 (β2)2 nACh receptor. CONCLUSIONS AND IMPLICATIONS These findings suggest that a triangle of residues from loops D, E and G contribute to the selective actions of neonicotinoids on insect-vertebrate hybrid nACh receptors. LINKED ARTICLES This article is part of a themed section on Nicotinic Acetylcholine Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.11/issuetoc.
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Affiliation(s)
- Makoto Ihara
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan
| | - Mai Hikida
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan
| | - Hiroyuki Matsushita
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan
| | - Kyosuke Yamanaka
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan
| | - Yuya Kishimoto
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan
| | - Kazuki Kubo
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan
| | - Shun Watanabe
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan
| | - Mifumi Sakamoto
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan
| | - Koutaro Matsui
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan
| | - Akihiro Yamaguchi
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan
| | - Daiki Okuhara
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan
| | - Shogo Furutani
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan
| | - David B Sattelle
- Centre for Respiratory Biology, UCL Respiratory, University College London, London, UK
| | - Kazuhiko Matsuda
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan
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Okuhara D, Furutani S, Ito K, Ihara M, Matsuda K. Splice Variants of pH-Sensitive Chloride Channel Identify a Key Determinant of Ivermectin Sensitivity in the Larvae of the Silkworm Bombyx mori. Mol Pharmacol 2017; 92:491-499. [PMID: 28739571 DOI: 10.1124/mol.117.109199] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 07/20/2017] [Indexed: 11/22/2022] Open
Abstract
The pH-sensitive chloride channels (pHCls) are broadly expressed in insects, but little is known about their physiologic role, diversity, and sensitivity to insecticides acting on relevant chloride channels. Here we have sequenced 50 transcripts of the pHCl-1 gene from the brain, third thoracic ganglion (T3G), and midgut of larvae of silkworm Bombyx mori It was found that >50 variants were expressed with distinct splicing in the T3G compared with the brain and midgut. Of the variants detected, variant 9, which was expressed most abundantly in the larvae, was reconstituted in Xenopus laevis oocytes to characterize its pH and ivermectin sensitivity. Variant 9 formed a functional pHCl with half-maximal activation at a pH of 7.87, and was activated by ivermectin irrespective of the extracellular pH. This was in contrast to variant 1, which was activated more profoundly at acidic rather than basic pH. To identify a key determinant for such differential ivermectin sensitivity, different amino acids in variants 1 and 9 were swapped, and the effects of the mutations on ivermectin sensitivity were investigated. The V275S mutation of variant 1 enhanced ivermectin sensitivity, whereas the S275V mutation of variant 9 caused a reduction in sensitivity. In homology models of the Bombyx pHCls, Val275 of variant 1 interacted more strongly with Ala273 than Ser275 of variant 9 at the channel gate. This interaction is likely to prevent ivermectin-induced opening of the channel, accounting, at least partially, for the differential macrolide action on the two variants.
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Affiliation(s)
- Daiki Okuhara
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan (D.O., S.F., M.I., K.M.); Department of Science of Biological Production, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan (K.I.)
| | - Shogo Furutani
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan (D.O., S.F., M.I., K.M.); Department of Science of Biological Production, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan (K.I.)
| | - Katsuhiko Ito
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan (D.O., S.F., M.I., K.M.); Department of Science of Biological Production, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan (K.I.)
| | - Makoto Ihara
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan (D.O., S.F., M.I., K.M.); Department of Science of Biological Production, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan (K.I.)
| | - Kazuhiko Matsuda
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kindai University, Nara, Japan (D.O., S.F., M.I., K.M.); Department of Science of Biological Production, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan (K.I.)
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159
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Boffi JC, Marcovich I, Gill-Thind JK, Corradi J, Collins T, Lipovsek MM, Moglie M, Plazas PV, Craig PO, Millar NS, Bouzat C, Elgoyhen AB. Differential Contribution of Subunit Interfaces to α9α10 Nicotinic Acetylcholine Receptor Function. Mol Pharmacol 2017; 91:250-262. [PMID: 28069778 PMCID: PMC5325082 DOI: 10.1124/mol.116.107482] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 01/04/2017] [Indexed: 12/31/2022] Open
Abstract
Nicotinic acetylcholine receptors can be assembled from either homomeric or heteromeric pentameric subunit combinations. At the interface of the extracellular domains of adjacent subunits lies the acetylcholine binding site, composed of a principal component provided by one subunit and a complementary component of the adjacent subunit. Compared with neuronal nicotinic acetylcholine cholinergic receptors (nAChRs) assembled from α and β subunits, the α9α10 receptor is an atypical member of the family. It is a heteromeric receptor composed only of α subunits. Whereas mammalian α9 subunits can form functional homomeric α9 receptors, α10 subunits do not generate functional channels when expressed heterologously. Hence, it has been proposed that α10 might serve as a structural subunit, much like a β subunit of heteromeric nAChRs, providing only complementary components to the agonist binding site. Here, we have made use of site-directed mutagenesis to examine the contribution of subunit interface domains to α9α10 receptors by a combination of electrophysiological and radioligand binding studies. Characterization of receptors containing Y190T mutations revealed unexpectedly that both α9 and α10 subunits equally contribute to the principal components of the α9α10 nAChR. In addition, we have shown that the introduction of a W55T mutation impairs receptor binding and function in the rat α9 subunit but not in the α10 subunit, indicating that the contribution of α9 and α10 subunits to complementary components of the ligand-binding site is nonequivalent. We conclude that this asymmetry, which is supported by molecular docking studies, results from adaptive amino acid changes acquired only during the evolution of mammalian α10 subunits.
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Affiliation(s)
- Juan Carlos Boffi
- Instituto de Investigaciones en Ingeniería, Genética y Biología Molecular, Dr Héctor N Torres (J.C.B., I.M., M.M. L., M.M., P.V.P., A.B.E.), Instituto de Química Biológica (P.O.C.), and Instituto de Investigaciones Bioquímicas de Bahía Blanca (J.C., C.B), Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; Department of Neuroscience, Physiology and Pharmacology, University College London, United Kingdom (J.K.G.-T., T.C., N.S.M.); Departamento de Química Biológica Facultad de Ciencias Exactas y Naturales (P.O.C.), and Instituto de Farmacología, Facultad de Medicina (P.V.P., A.B.E.), Universidad de Buenos Aires, Buenos Aires, Argentina; and Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina (J.C., C.B)
| | - Irina Marcovich
- Instituto de Investigaciones en Ingeniería, Genética y Biología Molecular, Dr Héctor N Torres (J.C.B., I.M., M.M. L., M.M., P.V.P., A.B.E.), Instituto de Química Biológica (P.O.C.), and Instituto de Investigaciones Bioquímicas de Bahía Blanca (J.C., C.B), Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; Department of Neuroscience, Physiology and Pharmacology, University College London, United Kingdom (J.K.G.-T., T.C., N.S.M.); Departamento de Química Biológica Facultad de Ciencias Exactas y Naturales (P.O.C.), and Instituto de Farmacología, Facultad de Medicina (P.V.P., A.B.E.), Universidad de Buenos Aires, Buenos Aires, Argentina; and Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina (J.C., C.B)
| | - JasKiran K Gill-Thind
- Instituto de Investigaciones en Ingeniería, Genética y Biología Molecular, Dr Héctor N Torres (J.C.B., I.M., M.M. L., M.M., P.V.P., A.B.E.), Instituto de Química Biológica (P.O.C.), and Instituto de Investigaciones Bioquímicas de Bahía Blanca (J.C., C.B), Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; Department of Neuroscience, Physiology and Pharmacology, University College London, United Kingdom (J.K.G.-T., T.C., N.S.M.); Departamento de Química Biológica Facultad de Ciencias Exactas y Naturales (P.O.C.), and Instituto de Farmacología, Facultad de Medicina (P.V.P., A.B.E.), Universidad de Buenos Aires, Buenos Aires, Argentina; and Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina (J.C., C.B)
| | - Jeremías Corradi
- Instituto de Investigaciones en Ingeniería, Genética y Biología Molecular, Dr Héctor N Torres (J.C.B., I.M., M.M. L., M.M., P.V.P., A.B.E.), Instituto de Química Biológica (P.O.C.), and Instituto de Investigaciones Bioquímicas de Bahía Blanca (J.C., C.B), Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; Department of Neuroscience, Physiology and Pharmacology, University College London, United Kingdom (J.K.G.-T., T.C., N.S.M.); Departamento de Química Biológica Facultad de Ciencias Exactas y Naturales (P.O.C.), and Instituto de Farmacología, Facultad de Medicina (P.V.P., A.B.E.), Universidad de Buenos Aires, Buenos Aires, Argentina; and Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina (J.C., C.B)
| | - Toby Collins
- Instituto de Investigaciones en Ingeniería, Genética y Biología Molecular, Dr Héctor N Torres (J.C.B., I.M., M.M. L., M.M., P.V.P., A.B.E.), Instituto de Química Biológica (P.O.C.), and Instituto de Investigaciones Bioquímicas de Bahía Blanca (J.C., C.B), Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; Department of Neuroscience, Physiology and Pharmacology, University College London, United Kingdom (J.K.G.-T., T.C., N.S.M.); Departamento de Química Biológica Facultad de Ciencias Exactas y Naturales (P.O.C.), and Instituto de Farmacología, Facultad de Medicina (P.V.P., A.B.E.), Universidad de Buenos Aires, Buenos Aires, Argentina; and Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina (J.C., C.B)
| | - María Marcela Lipovsek
- Instituto de Investigaciones en Ingeniería, Genética y Biología Molecular, Dr Héctor N Torres (J.C.B., I.M., M.M. L., M.M., P.V.P., A.B.E.), Instituto de Química Biológica (P.O.C.), and Instituto de Investigaciones Bioquímicas de Bahía Blanca (J.C., C.B), Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; Department of Neuroscience, Physiology and Pharmacology, University College London, United Kingdom (J.K.G.-T., T.C., N.S.M.); Departamento de Química Biológica Facultad de Ciencias Exactas y Naturales (P.O.C.), and Instituto de Farmacología, Facultad de Medicina (P.V.P., A.B.E.), Universidad de Buenos Aires, Buenos Aires, Argentina; and Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina (J.C., C.B)
| | - Marcelo Moglie
- Instituto de Investigaciones en Ingeniería, Genética y Biología Molecular, Dr Héctor N Torres (J.C.B., I.M., M.M. L., M.M., P.V.P., A.B.E.), Instituto de Química Biológica (P.O.C.), and Instituto de Investigaciones Bioquímicas de Bahía Blanca (J.C., C.B), Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; Department of Neuroscience, Physiology and Pharmacology, University College London, United Kingdom (J.K.G.-T., T.C., N.S.M.); Departamento de Química Biológica Facultad de Ciencias Exactas y Naturales (P.O.C.), and Instituto de Farmacología, Facultad de Medicina (P.V.P., A.B.E.), Universidad de Buenos Aires, Buenos Aires, Argentina; and Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina (J.C., C.B)
| | - Paola V Plazas
- Instituto de Investigaciones en Ingeniería, Genética y Biología Molecular, Dr Héctor N Torres (J.C.B., I.M., M.M. L., M.M., P.V.P., A.B.E.), Instituto de Química Biológica (P.O.C.), and Instituto de Investigaciones Bioquímicas de Bahía Blanca (J.C., C.B), Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; Department of Neuroscience, Physiology and Pharmacology, University College London, United Kingdom (J.K.G.-T., T.C., N.S.M.); Departamento de Química Biológica Facultad de Ciencias Exactas y Naturales (P.O.C.), and Instituto de Farmacología, Facultad de Medicina (P.V.P., A.B.E.), Universidad de Buenos Aires, Buenos Aires, Argentina; and Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina (J.C., C.B)
| | - Patricio O Craig
- Instituto de Investigaciones en Ingeniería, Genética y Biología Molecular, Dr Héctor N Torres (J.C.B., I.M., M.M. L., M.M., P.V.P., A.B.E.), Instituto de Química Biológica (P.O.C.), and Instituto de Investigaciones Bioquímicas de Bahía Blanca (J.C., C.B), Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; Department of Neuroscience, Physiology and Pharmacology, University College London, United Kingdom (J.K.G.-T., T.C., N.S.M.); Departamento de Química Biológica Facultad de Ciencias Exactas y Naturales (P.O.C.), and Instituto de Farmacología, Facultad de Medicina (P.V.P., A.B.E.), Universidad de Buenos Aires, Buenos Aires, Argentina; and Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina (J.C., C.B)
| | - Neil S Millar
- Instituto de Investigaciones en Ingeniería, Genética y Biología Molecular, Dr Héctor N Torres (J.C.B., I.M., M.M. L., M.M., P.V.P., A.B.E.), Instituto de Química Biológica (P.O.C.), and Instituto de Investigaciones Bioquímicas de Bahía Blanca (J.C., C.B), Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; Department of Neuroscience, Physiology and Pharmacology, University College London, United Kingdom (J.K.G.-T., T.C., N.S.M.); Departamento de Química Biológica Facultad de Ciencias Exactas y Naturales (P.O.C.), and Instituto de Farmacología, Facultad de Medicina (P.V.P., A.B.E.), Universidad de Buenos Aires, Buenos Aires, Argentina; and Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina (J.C., C.B)
| | - Cecilia Bouzat
- Instituto de Investigaciones en Ingeniería, Genética y Biología Molecular, Dr Héctor N Torres (J.C.B., I.M., M.M. L., M.M., P.V.P., A.B.E.), Instituto de Química Biológica (P.O.C.), and Instituto de Investigaciones Bioquímicas de Bahía Blanca (J.C., C.B), Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; Department of Neuroscience, Physiology and Pharmacology, University College London, United Kingdom (J.K.G.-T., T.C., N.S.M.); Departamento de Química Biológica Facultad de Ciencias Exactas y Naturales (P.O.C.), and Instituto de Farmacología, Facultad de Medicina (P.V.P., A.B.E.), Universidad de Buenos Aires, Buenos Aires, Argentina; and Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina (J.C., C.B)
| | - Ana Belén Elgoyhen
- Instituto de Investigaciones en Ingeniería, Genética y Biología Molecular, Dr Héctor N Torres (J.C.B., I.M., M.M. L., M.M., P.V.P., A.B.E.), Instituto de Química Biológica (P.O.C.), and Instituto de Investigaciones Bioquímicas de Bahía Blanca (J.C., C.B), Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; Department of Neuroscience, Physiology and Pharmacology, University College London, United Kingdom (J.K.G.-T., T.C., N.S.M.); Departamento de Química Biológica Facultad de Ciencias Exactas y Naturales (P.O.C.), and Instituto de Farmacología, Facultad de Medicina (P.V.P., A.B.E.), Universidad de Buenos Aires, Buenos Aires, Argentina; and Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina (J.C., C.B).
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