Rapid and efficient fusion of phospholipid vesicles by the α-helical core of a SNARE complex in the absence of an N-terminal regulatory domain
- Francesco Parlati,
- Thomas Weber,
- James A. McNew,
- Benedikt Westermann†,
- Thomas H. Söllner, and
- James E. Rothman‡
- Cellular Biochemistry and Biophysics Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, Box 251 New York, NY 10021
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Contributed by James E. Rothman
Abstract
A protease-resistant core domain of the neuronal SNARE complex consists of an α-helical bundle similar to the proposed fusogenic core of viral fusion proteins [Skehel, J. J. & Wiley, D. C. (1998) Cell 95, 871–874]. We find that the isolated core of a SNARE complex efficiently fuses artificial bilayers and does so faster than full length SNAREs. Unexpectedly, a dramatic increase in speed results from removal of the N-terminal domain of the t-SNARE syntaxin, which does not affect the rate of assembly of v-t SNARES. In the absence of this negative regulatory domain, the half-time for fusion of an entire population of lipid vesicles by isolated SNARE cores (≈10 min) is compatible with the kinetics of fusion in many cell types.
Footnotes
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↵ † Present address: Institute for Physiological Chemistry, Ludwig-Maximilians University Munich, Goethestrasse 33, 80336 Munich, Germany.
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↵ ‡ To whom reprint requests should be addressed. E-mail: j-rothman{at}ski.mskcc.org.
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See commentary on page 12227.
- Abbreviations:
- SYN/SNAP-25,
- syntaxin1/His6SNAP-25;
- tcSYN-SNAP-25,
- thrombin-cleavable syntaxin1/His6SNAP-25;
- SYN/tcSNAP-25,
- syntaxin1/thrombin-cleavableHis6SNAP-25;
- tcSYN/tcSNAP-25,
- thrombin-cleavable syntaxin1/thrombin-cleavableHis6SNAP-25;
- NBD,
- 7-nitrobenz-2-oxa-1,3-diazole;
- VAMP2,
- vesicle-associated membrane protein 2;
- PE,
- 1,2-dipalmitoyl phosphatidylethanolamine
- Copyright © 1999, The National Academy of Sciences
