The functional diversity of the neuronal nicotinic acetylcholine receptors is increased by a novel subunit: β4

Duvoisin, Robert M.; Deneris, Evan S.; Patrick, Jim; Heinemann, Sabine

doi:10.1016/0896-6273(89)90207-9

Cited by 287 publications

(180 citation statements)

References 39 publications

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“…In this respect these Drosophila a subunits resemble the rat cr2, a3, and cr4 subunits, which generate functional nAChRs when coexpressed with the /32 or /34 subunit but fail to do so with the /33 subunit Duvoisin et al, 1989;Luetje and Patrick, 1991). We have not detected specific radioligand binding when either of the two Drosophila /3 subunits is coexpressed with the rat cr3 or a4 subunit.…”

Section: Discussionmentioning

confidence: 71%

Temperature‐Sensitive Expression of Drosophila Neuronal Nicotinic Acetylcholine Receptors

Lansdell

Schmitt

Betz

et al. 1997

Journal of Neurochemistry

120

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Heterologous expression of cloned Drosophila nicotinic acetylcholine receptor (nAChR) subunits indicates that these proteins misfold when expressed in mammalian cell lines at 37°C.This misfolding can, however, be overcome either by growing transfected mammalian cells at lower temperatures or by the expression of Drosophila nAChR subunits in a Drosophila cell line. Whereas the Drosophila nAChR /3 subunit (SBD) cDNA, reported previously, lacked part of the SBD coding sequence, here we report the construction and expression of a full-length SBD cDNA. We have examined whether problems in expressing functional Drosophila nAChRs in either Xenopus oocytes or mammalian cell lines can be attributed to an inability of these expression systems to assemble correctly Drosophila nAChRs. Despite expression in what might be considered a more native cellular environment, we have been unable to detect functional nAChRs in a Drosophila cell line unless Drosophila nAChR subunit cDNA5 are coexpressed with vertebrate nAChR subunits. Our results indicate that the folding of Drosophila nAChR subunits is temperature-sensitive and strongly suggest that the inability of these Drosophila nAChR subunits to generate functional channels in the absence of vertebrate subunits is due to a requirement for coassembly with as yet unidentified Drosophila nAChR subunits. Key Words: Protein folding -Assembly-Nicotinic acetylcholine receptor.

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Section: Discussionmentioning

confidence: 71%

Temperature‐Sensitive Expression of Drosophila Neuronal Nicotinic Acetylcholine Receptors

Lansdell

Schmitt

Betz

et al. 1997

Journal of Neurochemistry

120

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“…Oocytes were defolliculated manually after treatment with collagenase type I (1.5 mg/ml calcium-free Barth's solution) for 1.5 h at room temperature. Plasmids coding for ␣3, ␣4, ␤2, and ␤4 subunits of rat neuronal nAChRs (Boulter et al, 1987;Duvoisin et al, 1989) were dissolved in distilled water. Stock solutions containing ␣4 or ␣3 and ␤2 or ␤4 subunit cDNAs at a 1:1 molar ratio were injected into the nuclei of stages V and VI oocytes within 8 h after harvesting, using a Drummond microinjector.…”

Section: Methodsmentioning

confidence: 99%

Selective effects of carbamate pesticides on rat neuronal nicotinic acetylcholine receptors and rat brain acetylcholinesterase

Smulders

Bueters²,

Kleef

et al. 2003

Toxicology and Applied Pharmacology

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Effects of commonly used carbamate pesticides on rat neuronal nicotinic acetylcholine receptors expressed in Xenopus laevis oocytes have been investigated using the two-electrode voltage clamp technique. The potencies of these effects have been compared to the potencies of the carbamates to inhibit rat brain acetylcholinesterase. The potency order of six carbamates to inhibit ␣4␤4 nicotinic receptors is fenoxycarb Ͼ EPTC Ͼ carbaryl, bendiocarb Ͼ propoxur Ͼ aldicarb with IC50 values ranging from 3 M for fenoxycarb to 165 M for propoxur and Ͼ1 mM for aldicarb. Conversely, the potency order of these carbamates to inhibit rat brain acetylcholinesterase is bendiocarb Ͼ propoxur, aldicarb Ͼ carbaryl Ͼ Ͼ EPTC, fenoxycarb with IC50 values ranging from 1 M for bendiocarb to 17 M for carbaryl and Ͼ Ͼ1 mM for EPTC and fenoxycarb. The ␣4␤2, ␣3␤4, and ␣3␤2 nicotinic acetylcholine receptors are inhibited by fenoxycarb, EPTC, and carbaryl with potency orders similar to that for ␣4␤4 receptors. Comparing the potencies of inhibition of the distinct subtypes of nicotinic acetylcholine receptors shows that the ␣3␤2 receptor is less sensitive to inhibition by fenoxycarb and EPTC. The potency of inhibition depends on the carbamate as well as on a combination of ␣ and ␤ subunit properties. It is concluded that carbamate pesticides affect different subtypes of neuronal nicotinic receptors independently of acetylcholinesterase inhibition. This implicates that neuronal nicotinic receptors are additional targets for some carbamate pesticides and that these receptors may contribute to carbamate pesticide toxicology, especially after long-term exposure.

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“…It does not express any channel activity in oocytes in combination with any other single subunit , nor has it been demonstrated at the protein level in the CNS. Both the ␤3 and ␤4 subunits seem, by in situ hybridization, to have a more restricted distribution than does the ␤2 subunit Duvoisin et al, 1989;Dineley-Miller and Patrick, 1992;Willoughby et al, 1993). Recent work has suggested that the ␤4 subunit is more widely expressed in the CNS than previously thought (Dineley-Miller and Patrick, 1992).…”

mentioning

confidence: 96%

Formation of Oligomers Containing the β3 and β4 Subunits of the Rat Nicotinic Receptor

Forsayeth

Kobrin

1997

J. Neurosci.

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The role of the ␤3 and ␤4 subunits of the nicotinic acetylcholine receptor in brain is still unclear. We investigated nicotinic receptor structure with antibodies directed against unique regions of the ␤3 and ␤4 subunits of the rat nicotinic acetylcholine receptor. Anti-␤4 detected a single band of 66 kDa in most regions of the brain that was strongest in striatum and cerebellum. The 60 kDa ␤3 subunit was detected primarily in striatum and cerebellum, and faintly in hippocampus. Immunoprecipitation experiments established that the two subunits were coassembled in the cerebellum along with the ␤2 subunit. Antibodies against the ␣4, ␤2, ␤3, and ␤4 subunits immunoprecipitated ϳ75% of the bungarotoxin-insensitive nicotinic receptor from cerebellar extracts as determined by nicotine-dependent acetylcholine binding. Transfection of COS cells with cDNAs for these four subunits induced expression of a high affinity nicotinic receptor. Omission of only a single subunit from the transfection affected either the B max or the apparent K D of the receptor. Our data suggest that the ␤3 subunit functions as a structural entity that links a relatively unstable ␣4␤2 heterodimer to a more stable ␣4␤4 heterodimer. The agonistbinding site formed by ␣4␤2 has a much greater affinity than does that formed by ␣4␤4. In this respect, nicotinic receptors that contain the ␤3 subunit are structurally homologous to the muscle nicotinic receptor.Key words: nicotine; acetylcholine; receptor; antibody; ␤3; ␤4; subunit Nicotinic acetylcholine receptors (nAChR) expressed in the CNS are members of a superfamily of ligand-gated ion channels that also include the muscle-type nAChR, GABA A , glycine, and 5-HT 3 receptors (Barnard et al., 1987;Egebjerg et al., 1991;Maricq et al., 1991;Moriyoshi et al., 1991;Monyer et al., 1992). Nine different rat neuronal nAChR subunit cDNAs (␣2, ␣3, ␣4, ␣5, ␣6, ␣7, ␤2, ␤3, and ␤4) have been cloned (for review, see Sargent, 1993). Most of the receptors in the family are thought to contain two or more different subunits, but the precise combinations of these subunits that exist in vivo are largely unknown. Previous work has indicated that the major high affinity nicotinic receptor in rat brain is composed of ␣4 and ␤2 subunits (Nakayama et al., 1991;Flores et al., 1992;Marks et al., 1992). More recent evidence indicates that deletion of the ␤2 subunit gene results in the loss of high affinity nicotine-binding sites from mouse brain (Picciotto et al., 1995). Nicotinic receptors have also been reconstituted in Xenopus oocytes. Thus, the ␤2 and ␤4 subunits can combine with various ␣ subunits to form functional receptors, permitting the formation of many types of receptor with unique pharmacological characteristics (Luetje and Patrick, 1991). Much less is known about the ␤3 subunit. It does not express any channel activity in oocytes in combination with any other single subunit , nor has it been demonstrated at the protein level in the CNS. Both the ␤3 and ␤4 subunits seem, by in situ hybridization, to have a more restric...

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The functional diversity of the neuronal nicotinic acetylcholine receptors is increased by a novel subunit: β4

Cited by 287 publications

References 39 publications

Temperature‐Sensitive Expression of Drosophila Neuronal Nicotinic Acetylcholine Receptors

Temperature‐Sensitive Expression of Drosophila Neuronal Nicotinic Acetylcholine Receptors

Selective effects of carbamate pesticides on rat neuronal nicotinic acetylcholine receptors and rat brain acetylcholinesterase

Formation of Oligomers Containing the β3 and β4 Subunits of the Rat Nicotinic Receptor

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