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Dα3, a New Functional α Subunit of Nicotinic Acetylcholine Receptors from Drosophila
Author(s) -
Schulz R.,
Sawruk E.,
Mülhardt C.,
Bertrand S.,
Baumann A.,
Phannavong B.,
Betz H.,
Bertrand D.,
Gundelfinger E. D.,
Schmitt B.
Publication year - 1998
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1998.71020853.x
Subject(s) - acetylcholine receptor , nicotinic agonist , cys loop receptors , protein subunit , biology , nicotinic acetylcholine receptor , receptor , interleukin 10 receptor, alpha subunit , g alpha subunit , microbiology and biotechnology , acetylcholine , biochemistry , gene , endocrinology
Nicotinic acetylcholine (ACh) receptors (nAChRs) are important excitatory neurotransmitter receptors in the insect CNS. We have isolated and characterized the gene and the cDNA of a new nAChR subunit from Drosophila . The predicted mature nAChR protein consists of 773 amino acid residues and has the structural features of an ACh‐binding α subunit. It was therefore named Dα3, for D rosophila α ‐subunit 3 . The dα3 gene maps to the X chromosome at position 7E. The properties of the Dα3 protein were assessed by expression in Xenopus oocytes. Dα3 did not form functional receptors on its own or in combination with any Drosophila β‐type nAChR subunit. Nondesensitizing ACh‐evoked inward currents were observed when Dα3 was coexpressed with the chick β2 subunit. Half‐maximal responses were at ∼0.15 µ M ACh with a Hill coefficient of ∼1.5. The snake venom component α‐bungarotoxin (100 n M ) efficiently but reversibly blocked Dα3/β2 receptors, suggesting that Dα3 may be a component of one of the previously described two classes of toxin binding sites in the Drosophila CNS.