SNARE complexes and neuroexocytosis: how many, how close?
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Updated: Aug 17, 2026

Utilizing Combined Methodologies to Define the Role of Plasma Membrane Delivery During Axon Branching and Neuronal Morphogenesis
Published on: March 16, 2016
Cesare Montecucco1, Giampietro Schiavo, Sergio Pantano
1Dipartimento di Scienze Biomediche and Istituto CNR di Neuroscienze, Università di Padova, Viale G. Colombo n. 3, 35121 Padova, Italy. cesare.montecucco@unipd.it
Abstract:
Regulated secretion is an essential process in all eukaryotic cells. The release of molecules contained inside exocytic granules and synaptic vesicles is mediated by the assembly of a SNARE complex formed by the coil-coiling of three proteins: SNAP-25, syntaxin and VAMP/synaptobrevin. It seems that SNARE complexes assemble together in rosette-shaped super-complexes but there is controversy on the actual number (N) of copies of SNARE complexes that are necessary to mediate exocytosis. We discuss attempts to determine the value of N and suggest that N varies with the type of exocytic vesicles. In addition, we propose that the N value in neuroexocytosis can be estimated by the comparative use of different types of botulinum neurotoxins.
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