title: Neurotransmitter acetylcholine negatively regulates neuromuscular synapse formation by a Cdk5-dependent mechanism.
abstract: Synapse formation requires interactions between pre- and postsynaptic cells to establish the connection of a presynaptic nerve terminal with the neurotransmitter receptor-rich postsynaptic apparatus. At developing vertebrate neuromuscular junctions, acetylcholine receptor (AChR) clusters of nascent postsynaptic apparatus are not apposed by presynaptic nerve terminals. Two opposing activities subsequently promote the formation of synapses: positive signals stabilize the innervated AChR clusters, whereas negative signals disperse those that are not innervated. Although the nerve-derived protein agrin has been suggested to be a positive signal, the negative signals remain elusive. Here, we show that cyclin-dependent kinase 5 (Cdk5) is activated by ACh agonists and is required for the ACh agonist-induced dispersion of the AChR clusters that have not been stabilized by agrin. Genetic elimination of Cdk5 or blocking ACh production prevents the dispersion of AChR clusters in agrin mutants. Therefore, we propose that ACh negatively regulates neuromuscular synapse formation through a Cdk5-dependent mechanism.
authors.affiliation: The Salk Institute, La Jolla, California 92037, USA.
authors.forename: Weichun
authors.initials: W
authors.lastname: Lin
authors.forename: Bertha
authors.initials: B
authors.lastname: Dominguez
authors.forename: Jiefei
authors.initials: J
authors.lastname: Yang
authors.forename: Prafulla
authors.initials: P
authors.lastname: Aryal
authors.forename: Eugene P
authors.initials: EP
authors.lastname: Brandon
authors.forename: Fred H
authors.initials: FH
authors.lastname: Gage
authors.forename: Kuo-Fen
authors.initials: KF
authors.lastname: Lee
mesh_terms: D000109:Acetylcholine / Q000502:physiology*; D018171:Agrin / Q000172:deficiency / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western / Q000379:methods; D002038:Bungarotoxins / Q000493:pharmacokinetics; D002217:Carbachol / Q000494:pharmacology; D002232:Carbocyanines / Q000493:pharmacokinetics; D002460:Cell Line; D002795:Choline O-Acetyltransferase / Q000172:deficiency; D018679:Cholinergic Agonists / Q000494:pharmacology; D051360:Cyclin-Dependent Kinase 5; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D003964:Diaphragm / Q000166:cytology; D004347:Drug Interactions; D004622:Embryo, Mammalian; D005260:Female; D018398:Homeodomain Proteins; D007150:Immunohistochemistry / Q000379:methods; D047468:Immunoprecipitation; D017403:In Situ Hybridization / Q000379:methods; D051379:Mice; D018345:Mice, Knockout; D009116:Muscarine / Q000494:pharmacology; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000378:metabolism; D009130:Muscle, Smooth / Q000187:drug effects / Q000196:embryology; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D009469:Neuromuscular Junction / Q000502:physiology*; D011247:Pregnancy; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011687:Purines / Q000494:pharmacology; D011940:Receptor Aggregation / Q000187:drug effects / Q000502:physiology*; D011950:Receptors, Cholinergic / Q000502:physiology*; D000077546:Roscovitine; D016708:Synaptophysin / Q000378:metabolism; D013997:Time Factors; D014157:Transcription Factors / Q000172:deficiency
chemical_list: D018171:Agrin; D002038:Bungarotoxins; D002232:Carbocyanines; D018679:Cholinergic Agonists; D018398:Homeodomain Proteins; C448385:N,N'-diethylthiacarbocyanine iodide; D047428:Protein Kinase Inhibitors; D011687:Purines; D011950:Receptors, Cholinergic; D016708:Synaptophysin; D014157:Transcription Factors; D000077546:Roscovitine; C084059:Hb9 protein, mouse; D009116:Muscarine; D002217:Carbachol; D002795:Choline O-Acetyltransferase; D051360:Cyclin-Dependent Kinase 5; C495906:Cdk5 protein, mouse; D018844:Cyclin-Dependent Kinases; D000109:Acetylcholine