Related Experiment Videos
Domain structure of synaptotagmin (p65)
The Journal of Biological Chemistry
|January 5, 1991
Summary
Synaptotagmin (p65) is a conserved synaptic vesicle protein with five domains. It forms dimers and complexes, and its structure suggests an exposed region critical for function in exocytosis.
Area of Science:
- Neuroscience
- Molecular Biology
- Cell Biology
Background:
- Synaptotagmin (p65) is an abundant, conserved protein found in synaptic vesicles.
- It possesses structural homology to protein kinase C regulatory regions.
Purpose of the Study:
- To investigate the biochemical properties and domain structure of synaptotagmin.
- To elucidate the oligomerization state and functional implications of its structure.
- To determine the subcellular localization and potential roles of synaptotagmin in different secretory vesicles.
Main Methods:
- Protein domain analysis and characterization.
- Biochemical assays including sucrose density gradient centrifugation and gel electrophoresis.
- Proteolytic digestion to identify exposed regions.
- Subcellular fractionation and antibody bead purification.
Main Results:
- Synaptotagmin exhibits five distinct protein domains, including glycosylated N-terminus, transmembrane region, and protein kinase C-homologous repeats.
- Synaptotagmin monomers dimerize, potentially mediated by an amphipathic alpha-helix in the third domain.
- A hypersensitive proteolytic site suggests an exposed region crucial for dimer function.
- Synaptotagmin co-localizes with synaptic vesicle markers in the brain but also associates with chromaffin granules in the adrenal medulla.
Conclusions:
- Synaptotagmin's structure supports its role in vesicle trafficking and exocytosis.
- The protein's dimerization and exposed regions are key to its function.
- Synaptotagmin participates in the exocytosis of both small synaptic vesicles and large dense-core catecholaminergic vesicles, indicating a broader role in regulated secretion.