NCAM 180 acting via a conserved C-terminal domain and MLCK is essential for effective transmission with repetitive stimulation

Neuron. 2005 Jun 16;46(6):917-31. doi: 10.1016/j.neuron.2005.05.018.

Abstract

NCAM 180 isoform null neuromuscular junctions are unable to effectively mobilize and exocytose synaptic vesicles and thus exhibit periods of total transmission failure during high-frequency repetitive stimulation. We have identified a highly conserved C-terminal (KENESKA) domain on NCAM that is required to maintain effective transmission and demonstrate that it acts via a pathway involving MLCK and probably myosin light chain (MLC) and myosin II. By perfecting a method of introducing peptides into adult NMJs, we tested the hypothesized role of proteins in this pathway by competitive disruption of protein-protein interactions. The effects of KENESKA and other peptides on MLCK and MLC activation and on failures in both wild-type and NCAM 180 null junctions supported this pathway, and serine phosphorylation of KENESKA was critical. We propose that this pathway is required to replenish synaptic vesicles utilized during high levels of exocytosis by facilitating myosin-driven delivery of synaptic vesicles to active zones or their subsequent exocytosis.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 4-Aminopyridine / analogs & derivatives*
  • 4-Aminopyridine / pharmacology
  • Action Potentials / drug effects
  • Action Potentials / physiology
  • Action Potentials / radiation effects
  • Amifampridine
  • Animals
  • Animals, Newborn
  • Blotting, Western / methods
  • Bungarotoxins / metabolism
  • Computational Biology / methods
  • Cysteamine / analogs & derivatives
  • Dose-Response Relationship, Drug
  • Dose-Response Relationship, Radiation
  • Electric Stimulation*
  • Heterocyclic Compounds, 4 or More Rings / pharmacology
  • Humans
  • Immunohistochemistry / methods
  • In Vitro Techniques
  • Mice
  • Mice, Knockout
  • Models, Neurological
  • Myosins / metabolism
  • Neural Cell Adhesion Molecules / chemistry
  • Neural Cell Adhesion Molecules / deficiency
  • Neural Cell Adhesion Molecules / metabolism*
  • Neuromuscular Junction / drug effects
  • Neuromuscular Junction / metabolism
  • Neuromuscular Junction / physiology
  • Neuromuscular Junction / radiation effects*
  • Oligopeptides / pharmacology
  • PC12 Cells
  • Peptide Fragments / pharmacology
  • Peptides / agonists
  • Peptides / antagonists & inhibitors
  • Peptides / metabolism*
  • Peptides / pharmacology
  • Potassium Channel Blockers / pharmacology
  • Protein Structure, Tertiary / physiology*
  • Rats
  • Signal Transduction / drug effects
  • Signal Transduction / physiology
  • Signal Transduction / radiation effects
  • Synaptic Transmission / drug effects
  • Synaptic Transmission / physiology
  • Synaptic Transmission / radiation effects*
  • Xenopus

Substances

  • Bungarotoxins
  • Heterocyclic Compounds, 4 or More Rings
  • Neural Cell Adhesion Molecules
  • Oligopeptides
  • Pep-1 peptide
  • Peptide Fragments
  • Peptides
  • Potassium Channel Blockers
  • MLCK peptide
  • blebbistatin
  • Cysteamine
  • 4-Aminopyridine
  • Myosins
  • Amifampridine