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Regulation of AP-2-synaptotagmin interaction by inositol high polyphosphates
A Mizutani1, M Fukuda, M Niinobe
1Molecular Neurobiology Laboratory, Tsukuba Life Science Center, Institute of Physical and Chemical Research (RIKEN), Ibaraki, Japan. amizutan@ims.u-tokyo.ac.jp
Biochemical and Biophysical Research Communications
|November 21, 1997
Summary
Inositol high-polyphosphates (IHPS) inhibit neurotransmission by binding to synaptotagmin (Syt), affecting protein interactions like Syt-AP2. This binding alters synaptic vesicle trafficking dynamics.
Area of Science:
- Neuroscience
- Molecular Biology
- Cell Biology
Background:
- Synaptic vesicle trafficking is crucial for neurotransmission.
- Synaptotagmins (Syt) are key synaptic vesicle membrane proteins involved in this process.
- Inositol high-polyphosphates (IHPS) are known to modulate neuronal function.
Purpose of the Study:
- To investigate the interaction between IHPS and synaptotagmins.
- To elucidate the role of IHPS in regulating protein-protein interactions at the synapse.
- To understand how IHPS binding to Syt affects synaptic vesicle trafficking.
Main Methods:
- Affinity elution chromatography using Syt II-immobilized Sepharose.
- Elution with InsP6 to identify interacting proteins.
- Comparative analysis of IHPS (InsP3 vs. InsP6) on Syt II-AP2 interaction.
- Limited trypsin digestion of synaptosomal fractions.
Main Results:
- Alpha adaptins (AP2) were eluted from Syt II, indicating an interaction.
- IHPS, particularly InsP6, significantly inhibited the Syt II-AP2 interaction.
- InsP6 altered protein cleavage patterns in synaptosomal fractions, suggesting conformational changes.
Conclusions:
- IHPS binding to the Syt C2B domain disrupts protein-protein interactions, including Syt-AP2.
- This disruption impacts synaptic vesicle trafficking.
- IHPS represents a potential regulator of synaptic function through modulation of Syt-mediated interactions.