Structural basis for the inhibitory role of tomosyn in exocytosis.
Details
Serval ID
serval:BIB_CE64699B2316
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Structural basis for the inhibitory role of tomosyn in exocytosis.
Journal
Journal of Biological Chemistry
ISSN
0021-9258 (Print)
ISSN-L
0021-9258
Publication state
Published
Issued date
2004
Peer-reviewed
Oui
Volume
279
Number
45
Pages
47192-47200
Language
english
Abstract
Upon Ca2+ influx synaptic vesicles fuse with the plasma membrane and release their neurotransmitter cargo into the synaptic cleft. Key players during this process are the Q-SNAREs syntaxin 1a and SNAP-25 and the R-SNARE synaptobrevin 2. It is thought that these membrane proteins gradually assemble into a tight trans-SNARE complex between vesicular and plasma membrane, ultimately leading to membrane fusion. Tomosyn is a soluble protein of 130 kDa that contains a COOH-terminal R-SNARE motif but lacks a transmembrane anchor. Its R-SNARE motif forms a stable core SNARE complex with syntaxin 1a and SNAP-25. Here we present the crystal structure of this core tomosyn SNARE complex at 2.0-A resolution. It consists of a four-helical bundle very similar to that of the SNARE complex containing synaptobrevin. Most differences are found on the surface, where they prevented tight binding of complexin. Both complexes form with similar rates as assessed by CD spectroscopy. In addition, synaptobrevin cannot displace the tomosyn helix from the tight complex and vice versa, indicating that both SNARE complexes represent end products. Moreover, data bank searches revealed that the R-SNARE motif of tomosyn is highly conserved throughout all eukaryotic kingdoms. This suggests that the formation of a tight SNARE complex is important for the function of tomosyn.
Keywords
Adaptor Proteins, Vesicular Transport, Amino Acid Motifs, Amino Acid Sequence, Animals, Anisotropy, Antigens, Surface/chemistry, Binding Sites, Calcium/metabolism, Cell Membrane/metabolism, Circular Dichroism, Crystallography, X-Ray, Electrophoresis, Polyacrylamide Gel, Escherichia coli/metabolism, Exocytosis, Membrane Fusion, Membrane Proteins/metabolism, Membrane Proteins/physiology, Microscopy, Fluorescence, Models, Molecular, Molecular Sequence Data, Nerve Tissue Proteins/chemistry, Nerve Tissue Proteins/metabolism, Protein Conformation, Protein Structure, Tertiary, R-SNARE Proteins, Rats, Recombinant Proteins/chemistry, Sequence Homology, Amino Acid, Signal Transduction, Synaptosomal-Associated Protein 25, Syntaxin 1, Time Factors, Vesicular Transport Proteins/chemistry, Vesicular Transport Proteins/physiology
Pubmed
Web of science
Open Access
Yes
Create date
15/09/2011 9:27
Last modification date
20/08/2019 16:48