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Complexin synchronizes primed vesicle exocytosis and regulates fusion pore dynamics
- Source :
- The Journal of Cell Biology
- Publication Year :
- 2014
-
Abstract
- ComplexinII and SynaptotagminI coordinately transform the constitutively active SNARE-mediated fusion mechanism into a highly synchronized, Ca2+-triggered release apparatus.<br />ComplexinII (CpxII) and SynaptotagminI (SytI) have been implicated in regulating the function of SNARE proteins in exocytosis, but their precise mode of action and potential interplay have remained unknown. In this paper, we show that CpxII increases Ca2+-triggered vesicle exocytosis and accelerates its secretory rates, providing two independent, but synergistic, functions to enhance synchronous secretion. Specifically, we demonstrate that the C-terminal domain of CpxII increases the pool of primed vesicles by hindering premature exocytosis at submicromolar Ca2+ concentrations, whereas the N-terminal domain shortens the secretory delay and accelerates the kinetics of Ca2+-triggered exocytosis by increasing the Ca2+ affinity of synchronous secretion. With its C terminus, CpxII attenuates fluctuations of the early fusion pore and slows its expansion but is functionally antagonized by SytI, enabling rapid transmitter discharge from single vesicles. Thus, our results illustrate how key features of CpxII, SytI, and their interplay transform the constitutively active SNARE-mediated fusion mechanism into a highly synchronized, Ca2+-triggered release apparatus.
- Subjects :
- Vesicle fusion
Chromaffin Cells
Vesicular Transport Proteins
Nerve Tissue Proteins
Biology
Membrane Fusion
Exocytosis
Synaptotagmin 1
Article
Mice
Synaptotagmins
Complexin
Animals
Secretion
Chromaffin Granules
Calcium Signaling
Cells, Cultured
Research Articles
Mice, Knockout
Secretory Vesicles
Lipid bilayer fusion
Membrane Proteins
Munc-18
Cell Biology
Secretory Vesicle
Cell biology
Adaptor Proteins, Vesicular Transport
Kinetics
SNARE Proteins
Subjects
Details
- ISSN :
- 15408140
- Volume :
- 204
- Issue :
- 7
- Database :
- OpenAIRE
- Journal :
- The Journal of cell biology
- Accession number :
- edsair.doi.dedup.....4c3afec6b53670c4f089eb43951ef3bb