Phosphorylation of the predicted major intracellular domains of the rat and chick neuronal nicotinic acetylcholine receptor alpha 7 subunit by cAMP-dependent protein kinase.
The predicted major intracellular domains of the chick and rat neuronal nicotinic acetylcholine receptor alpha 7 subunits were expressed in E. coli as glutathione-S-transferase fusion proteins. These proteins were then purified to near homogeneity by chromatography on immobilized glutathione. The intracellular domains of the alpha 7 subunit from both species were phosphorylated to high stoichiometry by cAMP-dependent protein kinase, but not by protein kinase C, cGMP-dependent protein kinase, or calcium/calmodulin-dependent protein kinase. Phosphorylation occurred on serine residues only within an identical single tryptic peptide for both proteins. This conserved phosphorylation site was identified as Ser 342 utilizing site-directed mutagenesis. These results demonstrate that the intracellular domain of the alpha 7 subunit is a substrate of PKA, and suggest a role for protein phosphorylation in mediating cellular regulation upon neuronal AChRs containing this subunit.
Moss
S J
SJ
Department of Pharmacology, University College London, U.K.
McDonald
B J
BJ
Rudhard
Y
Y
Schoepfer
R
R
D000595:Amino Acid Sequence; D000818:Animals; D002642:Chick Embryo; D017124:Conserved Sequence; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005982:Glutathione Transferase / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism*; D010449:Peptide Mapping; D010766:Phosphorylation; D010957:Plasmids; D051381:Rats; D011978:Receptors, Nicotinic / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis
D011978:Receptors, Nicotinic; D011993:Recombinant Fusion Proteins; D005982:Glutathione Transferase; D017868:Cyclic AMP-Dependent Protein Kinases