Distribution of components of the SNARE complex in relation to transmitter release sites at the frog neuromuscular junction.
At the frog neuromuscular junction, neurotransmitter release sites are regularly spaced at 1 micron intervals along the nerve terminal, directly facing postsynaptic folds which contain a high density of acetylcholine receptors. Immunostaining and laser confocal scanning microscopy were used to compare the distribution of presynaptic proteins implicated in exocytosis with that of fluorescent alpha-bungarotoxin. Syntaxin, synaptosome-associated 25 kDa protein and calcium channels were located predominantly at release sites. Synaptobrevin (vesicle-associated membrane protein) was distributed in the cytoplasm of the nerve terminal, presumably in the packets of microvesicles associated with each active zone. N-Ethylmaleimide-sensitive fusion protein (NSF) and soluble NSF attachment proteins (alpha beta SNAP) displayed a diffuse distribution throughout the terminal cytoplasm and also colocalized in distinct concentrated zones adjacent to the presynaptic membrane.
Boudier
J A
JA
INSERM U374, Institut Jean Roche, Faculté de Médecine Secteur Nord, Marseille, France.
Charvin
N
N
Boudier
J L
JL
Fathallah
M
M
Tagaya
M
M
Takahashi
M
M
Seagar
M J
MJ
D000818:Animals; D000906:Antibodies / Q000276:immunology; D015220:Calcium Channels / Q000276:immunology; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000276:immunology*; D018613:Microscopy, Confocal; D009469:Neuromuscular Junction / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D011896:Rana temporaria; D050600:SNARE Proteins; D033921:Vesicular Transport Proteins
D000906:Antibodies; D015220:Calcium Channels; D008565:Membrane Proteins; D018377:Neurotransmitter Agents; D050600:SNARE Proteins; D033921:Vesicular Transport Proteins