Selective formation of Sed5p-containing SNARE complexes is mediated by combinatorial binding interactions.
M M Tsui1, W C Tai, D K Banfield
1Department of Biology, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China.
Molecular Biology of the Cell
|March 17, 2001
Summary
Sed5p, a key Golgi protein, forms specific SNARE complexes essential for yeast protein transport. These complexes, identified in vitro, suggest distinct roles in multiple trafficking pathways.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Sed5p is the sole syntaxin required for protein transport in the yeast Golgi.
- Sed5p interacts with up to nine soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) proteins in vivo.
Purpose of the Study:
- To identify and characterize ternary and quaternary Sed5p-containing SNARE complexes in vitro.
- To investigate the selectivity and functional implications of Sed5p-mediated SNARE complex formation.
Main Methods:
- In vitro binding experiments to analyze SNARE complex formation.
- Biochemical and genetic analyses of Sed5p interactions.
Main Results:
- Identified specific ternary and quaternary Sed5p-SNARE complexes.
- Demonstrated syntaxin-selective and partner-discriminating complex formation.
- Showed that in vitro complex formation reflects distinct in vivo functional locales.
Conclusions:
- Sed5p-containing SNARE complex formation is selective and mediated by Sed5p intermediates.
- These complexes play overlapping or distinct roles in multiple yeast protein trafficking pathways.
- SNARE interactions are not promiscuous, suggesting specific functional roles rather than simple substitution.
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