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Interactions between presynaptic calcium channels and proteins implicated in synaptic vesicle trafficking and exocytosis.

M Seagar·M Takahashi
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Abstract

Monoclonal antibodies were generated by immunizing mice with chick brain synaptic membranes and screening for immunoprecipitation of solubilized omega conotoxin GVIA receptors (N-type calcium channels). Antibodies against two synaptic proteins (p35--syntaxin 1 and p58--synaptotagmin) were produced and used to purify and characterize a ternary complex containing N-type channels associated with these two proteins. These results provided the first evidence for a specific interaction between presynaptic calcium channels and SNARE proteins involved in synaptic vesicle docking and calcium-dependent exocytosis. Immunoprecipitation experiments supported the conclusion that syntaxin 1/SNAP-25/VAMP/synaptotagmin I or II complexes associate with N-type, P/Q-type, but not L-type calcium channels from rat brain nerve terminals. Immunofluorescent confocal microscopy at the frog neuromuscular junction was consistent with the co-localization of syntaxin 1, SNAP-25, and calcium channels, all of which are predominantly expressed at active zones of the presynaptic plasma membrane facing post-synaptic folds rich in acetylcholine receptors. The interaction of proteins implicated in calcium-dependent exocytosis with presynaptic calcium channels may locate the sensor(s) that trigger vesicle fusion within a microdomain of calcium entry.

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AnimalsCalciumCalcium ChannelsCalcium Channels, N-TypeCalcium SignalingCalcium-Binding ProteinsChickensExocytosisMacromolecular SubstancesMembrane GlycoproteinsMembrane ProteinsMiceModels, BiologicalNerve Tissue ProteinsPeptidesPresynaptic TerminalsProtein BindingQa-SNARE ProteinsR-SNARE ProteinsRatsSodium-Potassium-Exchanging ATPaseSynaptic VesiclesSynaptosomal-Associated Protein 25SynaptotagminsSyntaxin 1omega-Conotoxin GVIAJournal ArticleReview

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M Seagar, M Takahashi. 1998. Interactions between presynaptic calcium channels and proteins implicated in synaptic vesicle trafficking and exocytosis.. https://doi.org/10.1023/a%3A1021937605818

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