Synaptobrevin N-terminally bound to syntaxin—SNAP-25 defines the primed vesicle state in regulated exocytosis
| Autor: | Jakob B. Sørensen, Katrin Wiederhold, Dirk Fasshauer, Alexander M. Walter, Dieter Bruns |
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| Jazyk: | němčina |
| Rok vydání: | 2011 |
| Předmět: |
Vesicle fusion
Synaptosomal-Associated Protein 25 Physiology Synaptobrevin Biology Models Biological Exocytosis Article R-SNARE Proteins Mice ddc:570 Animals Calcium/metabolism Exocytosis/physiology Mice Knockout Qa-SNARE Proteins/genetics Qa-SNARE Proteins/metabolism R-SNARE Proteins/genetics R-SNARE Proteins/metabolism Rats SNARE Proteins/genetics SNARE Proteins/metabolism Secretory Vesicles/genetics Secretory Vesicles/metabolism Synaptosomal-Associated Protein 25/genetics Synaptosomal-Associated Protein 25/metabolism Research Articles Qa-SNARE Proteins Secretory Vesicles SNAP25 Munc-18 Cell Biology Kiss-and-run fusion Cell biology Porosome Calcium ddc:620 SNARE Proteins SNARE complex |
| Zdroj: | The Journal of Cell Biology Journal of Cell Biology, vol. 188, no. 3, pp. 401-413 |
| DOI: | 10.22028/d291-21398 |
| Popis: | Time-resolved measurements of exocytosis identify a domain of the SNARE complex required to keep vesicles readily releasable. Rapid neurotransmitter release depends on the ability to arrest the SNAP receptor (SNARE)–dependent exocytosis pathway at an intermediate “cocked” state, from which fusion can be triggered by Ca2+. It is not clear whether this state includes assembly of synaptobrevin (the vesicle membrane SNARE) to the syntaxin–SNAP-25 (target membrane SNAREs) acceptor complex or whether the reaction is arrested upstream of that step. In this study, by a combination of in vitro biophysical measurements and time-resolved exocytosis measurements in adrenal chromaffin cells, we find that mutations of the N-terminal interaction layers of the SNARE bundle inhibit assembly in vitro and vesicle priming in vivo without detectable changes in triggering speed or fusion pore properties. In contrast, mutations in the last C-terminal layer decrease triggering speed and fusion pore duration. Between the two domains, we identify a region exquisitely sensitive to mutation, possibly constituting a switch. Our data are consistent with a model in which the N terminus of the SNARE complex assembles during vesicle priming, followed by Ca2+-triggered C-terminal assembly and membrane fusion. |
| Databáze: | OpenAIRE |
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