Cross-linking of 125I-alpha-bungarotoxin to Drosophila head membranes identifies a 42 kDa toxin binding polypeptide.
The nicotinic acetylcholine receptor (nAChR) antagonist alpha-bungarotoxin (alpha-Btx) binds to two different classes of high affinity binding sites from the Drosophila central nervous system. We have used the bivalent reagent 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide (EDAC) to cross-link 125I-alpha-Btx (M(r) = 8 kDa) to Drosophila head membranes. Upon sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE), one major adduct of M(r) approximately 50 kDa was identified, suggesting that a 42 kDa polypeptide binds the toxin. Adduct formation was inhibited by other cholinergic ligands. Detergent-solubilized receptor complexes containing the cross-linked products were immunoprecipitated by antisera against two nAChR subunits previously identified by molecular cloning, the ALS and ARD proteins, suggesting that the 42 kDa toxin binding polypeptide constitutes a component of the previously described class 1 alpha-Btx binding site.
Schloss
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P
Max-Planck-Institut für Hirnforschung, Abteilung Neurochemie, Frankfurt, FRG.
Mayser
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W
Gundelfinger
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ED
Betz
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H
D000818:Animals; D002038:Bungarotoxins / Q000378:metabolism*; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D004330:Drosophila / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D008024:Ligands; D008566:Membranes / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D010455:Peptides / Q000378:metabolism*; D011233:Precipitin Tests; D011978:Receptors, Nicotinic / Q000187:drug effects; D064569:alpha7 Nicotinic Acetylcholine Receptor
D002038:Bungarotoxins; D003432:Cross-Linking Reagents; D007457:Iodine Radioisotopes; D008024:Ligands; D009419:Nerve Tissue Proteins; D010455:Peptides; D011978:Receptors, Nicotinic; D064569:alpha7 Nicotinic Acetylcholine Receptor