Reversible phosphorylation of the membrane-bound acetylcholine receptor

J Supramol Struct. 1980;14(2):163-74. doi: 10.1002/jss.400140205.

Abstract

We have found that the acetylcholine receptor (AChR) of Torpedo californica is phosphorylated and dephosphorylated in situ by a membrane-bound protein kinase and phosphatase [1]. There is increasing evidence that other neurotransmitters [2], light [3-6], polypeptide hormones [7], and growth factors [8-12] also may act by regulating the level of phosphorylation of membrane proteins. These observations suggest that membrane protein phosphorylation may be a general regulatory mechanism affecting the response of cells to exogenous metabolic and physical signals. To understand the role of membrane protein phosphorylation, we have chosen to study acetylcholine receptor-enriched membranes purified from the electric organ of T californica. This organ is an ideal model system for such studies since it is a rich source of the acetylcholine receptor. Membranes can be purified from the electric organ that are enriched in the AChR[13] and that show cholinergic agonist-dependent changes in cation flux [14]. Moreover, the AChR from T californica has been purified [15[, biochemically characterized [16], and used to generate specific antibodies [17]. Receptor, enriched membranes contain only a few other proteins that are closely associated with the receptor in the postsynaptic membrane. Such associated proteins may play a critical role in regulating the function of the AChR in the postsynaptic membrane. We have taken advantage of these conditions to study phosphorylation of the membrane-bound AChR in this well-defined, homogeneous system.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphate
  • Animals
  • Cell Membrane / metabolism
  • Electric Organ / metabolism*
  • Fishes
  • Guanosine Triphosphate
  • Kinetics
  • Molecular Weight
  • Phosphoprotein Phosphatases / metabolism*
  • Phosphorylation
  • Protein Kinases / metabolism*
  • Protein Phosphatase 1
  • Receptors, Cholinergic / metabolism*
  • Substrate Specificity

Substances

  • Receptors, Cholinergic
  • Guanosine Triphosphate
  • Adenosine Triphosphate
  • Protein Kinases
  • Phosphoprotein Phosphatases
  • Protein Phosphatase 1