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Document Version Version Comment Date Status
17120.0 [No comment] 10.11.2010 13:22 Released

ID: 17120.0, MPI für biophysikalische Chemie / Membranbiophysik (Prof. Erwin Neher)
The SNARE protein SNAP-25 is linked to fast calcium triggering of exocytosis
Authors:Soerensen, J. B.; Matti, U.; Wei, S. H.; Nehring, R.; Voets, T.; Ashery, U.; Binz, T.; Neher, E.; Rettig, J.
Date of Publication (YYYY-MM-DD):2002-02-05
Title of Journal:Proceedings of the National Academy of Sciences of the United States of America
Issue / Number:3
Start Page:1627
End Page:1632
Review Status:Peer-review
Audience:Not Specified
Abstract / Description:Synchronous neurotransmission depends on the tight coupling between Ca2+ influx and fusion of neurotransmitter-filled vesicles with the plasma membrane. The vesicular soluble N- ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein synaptobrevin 2 and the plasma membrane SNARES syntaxin 1 and synaptosomal protein of 25 kDa (SNAP-25) are essential for calcium-triggered exocytosis. However, the link between calcium triggering and SNARE function remains elusive. Here we describe mutations in two sites on the surface of the SNARE complex formed by acidic and hydrophilic residues of SNAP-25 and synaptobrevin 2, which were found to coordinate divalent cations in the neuronal SNARE complex crystal structure, By reducing the net charge of the site in SNAP-25 we identify a mutation that interferes with calcium triggering of exocytosis when overexpressed in chromaffin cells. Exocytosis was elicited by photorelease of calcium from a calcium cage and evaluated by using patch-clamp capacitance measurements at millisecond time resolution. We present a method for monitoring the dependence of exocytotic rate upon calcium concentration at the release site and demonstrate that the mutation decreased the steepness of this relationship, indicating that the number of sequential calcium-binding steps preceding exocytosis is reduced by one. We conclude that the SNARE complex is linked directly to calcium triggering of exocytosis, most likely in a complex with auxiliary proteins.
Comment of the Author/Creator:Date: 2002, FEB 5
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für biophysikalische Chemie/Abt. Erwin Neher / 140
External Affiliations:Med Hochsch Hannover, Inst Physiol Chem, D-30625 Hannover, Germany; Univ Saarland, Physiol Inst, D-66424 Homburg, Germany