Phosphorylation of membrane-bound acetylcholine receptor by protein kinase C: characterization and subunit specificity.
Acetylcholine receptor (AChR) from Torpedo electric organ in its membrane-bound or solubilized form is phosphorylated by the Ca2+/phospholipid-dependent protein kinase (PKC). The subunit specificity for PKC is different from that observed for cAMP-dependent protein kinase (PKA). Whereas PKC phosphorylates predominantly the delta subunit and the phosphorylation of the gamma subunit by this enzyme is very low, PKA phosphorylates both subunits to a similar high extent. We have extended our phosphorylation studies to a synthetic peptide from the gamma subunit, corresponding to residues 346-359, which contains a consensus PKA phosphorylation site. This synthetic peptide is phosphorylated by both PKA and PKC, suggesting that in the intact receptor both kinases may phosphorylate the gamma subunit at a similar site, as has been previously demonstrated by us for the delta subunit [Safran, A., et al. (1987) J. Biol. Chem. 262, 10506-10510]. The diverse pattern of phosphorylation of AChR by PKA and PKC may play a role in the regulation of its function.
Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel.
A
A
Safran
C
C
Provenzano
R
R
Sagi-Eisenberg
S
S
Fuchs
D000595:Amino Acid Sequence; D000818:Animals; D008565:Membrane Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D011978:Receptors, Nicotinic / Q000378:metabolism*; D013379:Substrate Specificity; D014101:Torpedo
D008565:Membrane Proteins; D010446:Peptide Fragments; D011978:Receptors, Nicotinic; D011494:Protein Kinases; D011493:Protein Kinase C