Neuronal nicotinic acetylcholine receptors in Drosophila: antibodies against an alpha-like and a non-alpha-subunit recognize the same high-affinity alpha-bungarotoxin binding complex.
ALS and ARD proteins are thought to represent a ligand binding and a structural subunit, respectively, of Drosophila nicotinic acetylcholine receptors (nAChRs). Here, antibodies raised against fusion constructs encompassing specific regions of the ALS and ARD proteins were used to investigate a potential association of these two polypeptides. Both ALS and ARD antisera removed 20-30% of the high-affinity binding sites for the nicotinic antagonist 125I-alpha-bungarotoxin (125I-alpha-Btx) from detergent extracts of fly head membranes. Combinations of both types of antisera also precipitated the same fraction of alpha-Btx binding sites, a result suggesting that both polypeptides are components of the previously defined class I 125I-alpha-Btx binding sites in the Drosophila CNS. 125I-alpha-Btx binding to a MS2 polymerase-ALS fusion protein containing the predicted antagonist binding region showed that the ALS protein indeed constitutes the ligand binding subunit of a nicotinic receptor complex. These data are consistent with neuronal nAChRs in Drosophila containing at least two types of subunits, ligand binding and structural ones.
ZMBH, Universität Heidelberg, F.R.G.
P
P
Schloss
H
H
Betz
C
C
Schröder
E D
ED
Gundelfinger
D000818:Animals; D000906:Antibodies; D000936:Antigen-Antibody Complex; D002038:Bungarotoxins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D004330:Drosophila / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D046911:Macromolecular Substances; D008961:Models, Structural; D009474:Neurons / Q000378:metabolism*; D011487:Protein Conformation; D011978:Receptors, Nicotinic / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D064569:alpha7 Nicotinic Acetylcholine Receptor
D000906:Antibodies; D000936:Antigen-Antibody Complex; D002038:Bungarotoxins; D046911:Macromolecular Substances; D011978:Receptors, Nicotinic; D011993:Recombinant Fusion Proteins; D064569:alpha7 Nicotinic Acetylcholine Receptor