Abstract
Cytotoxic T lymphocytes kill virus-infected and tumorigenic target cells through the release of perforin and granzymes via fusion of lytic granules at the contact site, the immunological synapse. It has been postulated that this fusion process is mediated by non-neuronal members of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor complex protein family. Here, using a synaptobrevin2-monomeric red fluorescence protein knock-in mouse we demonstrate that, surprisingly, the major neuronal v-SNARE synaptobrevin2 is expressed in cytotoxic T lymphocytes and exclusively localized on granzyme B-containing lytic granules. Cleavage of synaptobrevin2 by tetanus toxin or ablation of the synaptobrevin2 gene leads to a complete block of lytic granule exocytosis while leaving upstream events unaffected, identifying synaptobrevin2 as the v-SNARE responsible for the fusion of lytic granules at the immunological synapse.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Blotting, Western
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Cell Degranulation / drug effects
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Cytoplasmic Granules / drug effects
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Cytoplasmic Granules / metabolism*
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Cytoplasmic Granules / ultrastructure
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Cytotoxicity, Immunologic* / drug effects
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Flow Cytometry
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Gene Knock-In Techniques
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Green Fluorescent Proteins / metabolism
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Immunological Synapses / drug effects
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Immunological Synapses / metabolism
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Membrane Fusion* / drug effects
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Mice
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Protein Transport / drug effects
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Recombinant Fusion Proteins / metabolism
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SNARE Proteins / metabolism*
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T-Lymphocytes, Cytotoxic / cytology*
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T-Lymphocytes, Cytotoxic / drug effects
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T-Lymphocytes, Cytotoxic / metabolism*
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T-Lymphocytes, Cytotoxic / ultrastructure
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Tetanus Toxin / pharmacology
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Vesicle-Associated Membrane Protein 2 / metabolism*
Substances
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Recombinant Fusion Proteins
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SNARE Proteins
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Tetanus Toxin
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Vesicle-Associated Membrane Protein 2
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vesicle-associated membrane protein 2, mouse
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Green Fluorescent Proteins