The ionic layer is required for efficient dissociation of the SNARE complex by alpha-SNAP and NSF
S J Scales1, B Y Yoo, R H Scheller
1Howard Hughes Medical Institute, Department of Molecular and Cellular Physiology, Stanford University School of Medicine, CA 94305-5345, USA.
Summary
The SNARE complex
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- The SNARE complex is crucial for intracellular membrane fusion.
- It features a conserved ionic layer at its core with an unknown function.
- This layer comprises glutamine (Q) and arginine (R) residues (3Q:1R ratio).
Purpose of the Study:
- To investigate the function of the ionic layer in the SNARE complex.
- To determine the role of the syntaxin glutamine residue in complex dissociation.
Main Methods:
- Site-directed mutagenesis of the syntaxin glutamine residue.
- Analysis of alpha-SNAP and NSF binding and ATP hydrolysis-dependent dissociation.
- Assessment of SNARE complex monomer dissociation.
Main Results:
- Mutating the syntaxin ionic-layer glutamine prevents SNARE complex dissociation into monomers.
- The SNARE complex still binds alpha-SNAP and NSF and undergoes ATP hydrolysis.
- Dissociation is uncoupled from ATP hydrolysis upon mutation of this key glutamine.
Conclusions:
- The syntaxin ionic-layer glutamine is essential for coupling NSF's ATP hydrolysis to SNARE complex disassembly.
- alpha-SNAP and NSF likely induce conformational changes at the ionic layer via syntaxin glutamine.
- This interaction facilitates the dissociation of the SNARE complex into its constituent proteins.
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