title: Monoclonal antibodies against the acetylcholine receptor gamma-subunit as site specific probes for receptor tyrosine phosphorylation.
abstract: Tyrosine phosphorylation of the nicotinic acetylcholine receptor (AChR) may be involved in AChR desensitization and clustering. Torpedo AChR gamma-subunit is phosphorylated at Tyr365. Using overlapping synthetic peptides, we have precisely mapped the epitopes of five anti-gamma-subunit monoclonal antibodies (mAbs) and found that the epitope(s) for the mAbs 154, 165 and 168 (gamma 365-370) all contain Tyr365. mAb 168 is a known blocker of AChR channel function. Using peptide analogues, Tyr365 was found to be indispensable for mAb165 binding; furthermore its binding was selectively inhibited by in vitro AChR tyrosine phosphorylation. The possible connection between gamma-subunit phosphorylation and regulation of AChR function and the proven usefulness of these mAbs as tools should facilitate functional studies of AChR gamma-subunit phosphorylation.
authors.affiliation: Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece.
authors.forename: S J
authors.initials: SJ
authors.lastname: Tzartos
authors.forename: E
authors.initials: E
authors.lastname: Tzartos
authors.forename: J S
authors.initials: JS
authors.lastname: Tzartos
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D001666:Binding Sites, Antibody; D018604:Epitope Mapping; D000939:Epitopes / Q000737:chemistry / Q000276:immunology; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D019000:Phosphotyrosine; D051381:Rats; D011950:Receptors, Cholinergic / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D014101:Torpedo; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000032:analysis / Q000276:immunology / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D010446:Peptide Fragments; D011950:Receptors, Cholinergic; D019000:Phosphotyrosine; D014443:Tyrosine