Related Experiment Video
Updated: Jul 17, 2026
06:45
In Vivo Single-Molecule Tracking at the Drosophila Presynaptic Motor Nerve Terminal
Published on: January 14, 2018
Docking of secretory vesicles is syntaxin dependent.
Heidi de Wit1, L Niels Cornelisse, Ruud F G Toonen
1Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam and VU Medical Center, Amsterdam, Netherlands.
Plos One
|January 6, 2007
Summary
Syntaxin, a protein, is crucial for secretory vesicle docking in neuroendocrine cells, challenging previous beliefs about its independence from SNARE proteins. Its absence halts vesicle fusion, revealing a key role in this process.
Area of Science:
- Neurobiology
- Cell Biology
- Molecular Biology
Background:
- Secretory vesicle fusion with the plasma membrane is essential for cellular function.
- The molecular mechanisms of vesicle docking are not fully understood.
- Vesicle docking is often considered independent of SNARE proteins.
Purpose of the Study:
- To investigate the role of the SNARE protein syntaxin in secretory vesicle docking and fusion.
- To challenge the hypothesis that SNARE proteins are not involved in vesicle docking.
Main Methods:
- Acute deletion of syntaxin in vertebrate neurons and neuroendocrine cells.
- Morphological analysis of secretory vesicle docking.
- Assessment of Munc18-1 localization.
- Analysis of the sub-membrane cortical actin network.
Main Results:
- Syntaxin deletion caused fusion arrest in both neurons and neuroendocrine cells.
- No docking defects were observed in synapses.
- A significant reduction in morphologically docked secretory vesicles was found in chromaffin cells.
- Syntaxin deficiency led to minor Munc18-1 reductions and unaffected actin networks.
Conclusions:
- Syntaxin plays a critical role in secretory vesicle docking in neuroendocrine cells.
- This docking role contrasts with its apparent redundancy in highly specialized systems like synaptic active zones.
- The findings suggest complex regulatory mechanisms for vesicle docking.
More Related Videos
Related Concept Videos
01:26Fusion of Secretory Vesicles with the Plasma Membrane
Proteins and neurotransmitters in secretory vesicles can be released from a cell upon vesicle docking, priming, and fusion with the plasma membrane. Vesicles are docked and primed in preparation for the quick exocytosis of their contents in response to a stimulus. The fusion process is mainly carried out by a SNAP Receptor or SNARE complex, consisting of synaptobrevin, syntaxin-1, and SNAP-25.
In 1993, Jim Rothman proposed that the antiparallel pairing of vesicular and transmembrane SNAREs, or...
In 1993, Jim Rothman proposed that the antiparallel pairing of vesicular and transmembrane SNAREs, or...
01:33Overview of Secretory Vesicles
Secretory vesicles, also known as dense core vesicles (DCVs), are membrane-bound vesicles that transport secretory proteins, such as hormones or neurotransmitters. Regulated secretory vesicles transport proteins from the trans-Golgi network to the exterior of the cell. Proteins present in regulated secretory vesicles are required to be rapidly exocytosed in large amounts upon a specific stimulus.
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
01:32Pinching-off of Coated Vesicles
Vesicle budding is orchestrated by distinct cytosolic proteins such as adaptor proteins, coat proteins, and GTPases. To initiate vesicle budding, membrane-bending proteins containing crescent-shaped BAR domains bind to the lipid heads in the bilayer and distort the membrane to form a protein-coated vesicle bud. Adaptors proteins such as AP2 for clathrin-coated vesicles can nucleate on the deformed membrane. Finally, coat proteins such as clathrin or COPI and COPII assemble into a coat forming...
01:45Vesicular Tubular Clusters
After budding out from the ER membrane, some COPII vesicles lose their coat and fuse with one another to form larger vesicles and interconnected tubules called vesicular tubular clusters or VTCs. These clusters constitute a compartment at the ER-Golgi interface known as ERGIC (Endoplasmic Reticulum Golgi Intermediate Compartment). The ERGIC is a mobile membrane-bound cargo transport system that sorts proteins secreted from ER and delivers them to the Golgi.
With the help of motor proteins such...
With the help of motor proteins such...
01:43SNAREs and Membrane Fusion
Once a transport vesicle has recognized its target organelle, the vesicular membrane needs to fuse with the target membrane to unload the cargo. Transmembrane proteins called SNAREs present on organelle membranes and their vesicles, mediate vesicle fusion.
SNAREs exist in pairs that symmetrically interact and catalyze the fusion of the lipid bilayers in vesicle and target organelle. v-SNARE in the vesicle membrane are single polypeptide chains that bind to a complementary t-SNARE, composed of 2...
SNAREs exist in pairs that symmetrically interact and catalyze the fusion of the lipid bilayers in vesicle and target organelle. v-SNARE in the vesicle membrane are single polypeptide chains that bind to a complementary t-SNARE, composed of 2...
01:12Clathrin Coated Vesicles
Clathrin-coated vesicles use endocytosis to transport receptors and lysosomal hydrolases from the Golgi to the lysosome in the late secretory pathway. Clathrin-mediated endocytosis was the first described endocytic process, and Clathrin-coated vesicles remain one of the most well-studied transport vesicles. The molecular machinery that generates clathrin-coated vesicles comprises over 50 proteins that precisely coordinate vesicle formation. Cell surface receptors concentrated in indented sites...