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Imaging FITC-dextran as a Reporter for Regulated Exocytosis
Published on: June 20, 2018
Real-time visualization of complexin during single exocytic events
Seong J An1, Chad P Grabner, David Zenisek
1Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, USA. seong.an@yale.edu
Nature Neuroscience
|April 13, 2010
Summary
Complexin (cplx) binds soluble NSF attachment protein receptor (SNARE) complexes during membrane fusion. This protein regulates fusion pore dynamics, ensuring complete cargo release during exocytosis.
Area of Science:
- Cell biology
- Membrane trafficking
- Biophysics
Background:
- Soluble NSF attachment protein receptor (SNARE) complexes are crucial for membrane fusion events, such as exocytosis.
- Understanding the spatiotemporal dynamics of SNARE complex assembly is key to elucidating their fundamental role.
Purpose of the Study:
- To visualize the dynamics of complexin (cplx) during single exocytic events in live cells.
- To investigate the role of cplx in modulating the structure and function of fusion pores.
Main Methods:
- Live-cell imaging of single exocytic events.
- Utilizing a truncated complexin mutant to probe SNARE-complex binding region function.
- Tracking release of transmitter and lipid probes through fusion pores.
Main Results:
- Complexin (cplx) transiently appeared during full fusion events.
- A truncated cplx mutant, lacking regulatory domains, persisted at fusion sites, leading to transient fusion.
- Fusion pores exhibited narrow structures, not purely lipidic, and partial cargo release was observed with the cplx mutant and cplx depletion.
Conclusions:
- Complexin (cplx) is recruited late in the exocytosis process.
- Cplx plays a critical role in modulating the structure and dynamics of SNARE complex-mediated fusion pores.
- Proper cplx function is essential for complete secretory cargo release.
