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A SNARE complex mediating fusion of late endosomes defines conserved properties of SNARE structure and function
Author(s) -
Antonin Wolfram,
Holroyd Claudia,
Fasshauer Dirk,
Pabst Stefan,
von Mollard Gabriele Fischer,
Jahn Reinhard
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.23.6453
Subject(s) - syntaxin , snare complex , endosome , biology , lipid bilayer fusion , microbiology and biotechnology , vesicular transport proteins , transmembrane protein , transmembrane domain , syntaxin 3 , fusion protein , membrane protein , intracellular , biochemistry , membrane , receptor , vacuolar protein sorting , recombinant dna , gene
Sets of SNARE proteins mediate membrane fusion by assembling into core complexes. Multiple SNAREs are thought to function in different intracellular trafficking steps but it is often unclear which of the SNAREs cooperate in individual fusion reactions. We report that syntaxin 7, syntaxin 8, vti1b and endobrevin/VAMP‐8 form a complex that functions in the fusion of late endosomes. Antibodies specific for each protein coprecipitate the complex, inhibit homotypic fusion of late endosomes in vitro and retard delivery of endocytosed epidermal growth factor to lysosomes. The purified proteins form core complexes with biochemical and biophysical properties remarkably similar to the neuronal core complex, although each of the four proteins carries a transmembrane domain and three have independently folded N‐terminal domains. Substitution experiments, sequence and structural comparisons revealed that each protein occupies a unique position in the complex, with syntaxin 7 corresponding to syntaxin 1, and vti1b and syntaxin 8 corresponding to the N‐ and C‐terminal domains of SNAP‐25, respectively. We conclude that the structure of core complexes and their molecular mechanism in membrane fusion is highly conserved between distant SNAREs.