NCAM 180 acting via a conserved C-terminal domain and MLCK is essential for effective transmission with repetitive stimulation.
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.
Polo-Parada
Luis
L
Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
Plattner
Florian
F
Bose
Christian
C
Landmesser
Lynn T
LT
D015761:4-Aminopyridine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D000077770:Amifampridine; D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western / Q000379:methods; D002038:Bungarotoxins / Q000378:metabolism; D019295:Computational Biology / Q000379:methods; D003543:Cysteamine / Q000031:analogs & derivatives; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation; D006576:Heterocyclic Compounds, 4 or More Rings / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D066298:In Vitro Techniques; D051379:Mice; D018345:Mice, Knockout; D008959:Models, Neurological; D009218:Myosins / Q000378:metabolism; D019006:Neural Cell Adhesion Molecules / Q000737:chemistry / Q000172:deficiency / Q000378:metabolism*; D009469:Neuromuscular Junction / Q000187:drug effects / Q000378:metabolism / Q000502:physiology / Q000528:radiation effects*; D009842:Oligopeptides / Q000494:pharmacology; D016716:PC12 Cells; D010446:Peptide Fragments / Q000494:pharmacology; D010455:Peptides / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D026902:Potassium Channel Blockers / Q000494:pharmacology; D017434:Protein Structure, Tertiary / Q000502:physiology*; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects*; D014981:Xenopus
D002038:Bungarotoxins; D006576:Heterocyclic Compounds, 4 or More Rings; D019006:Neural Cell Adhesion Molecules; D009842:Oligopeptides; C503924:Pep-1 peptide; D010446:Peptide Fragments; D010455:Peptides; D026902:Potassium Channel Blockers; C065738:MLCK peptide; C472645:blebbistatin; D003543:Cysteamine; D015761:4-Aminopyridine; D009218:Myosins; D000077770:Amifampridine