Abstract
In yeast, the Class C Vps protein complex (C-Vps complex), composed of Vps11, Vps16, Vps18, and Vps33, functions in Golgi-to-vacuole protein transport. In this study, we characterized and purified this complex and identified its interaction with the syntaxin homolog Vam3. Vam3 pairs with the SNAP-25 homolog Vam7 and VAMP homolog Vti1 to form SNARE complexes during vesicle docking/fusion with the vacuole. The C-Vps complex does not bind to Vam3-Vti1-Vam7 paired SNARE complexes but instead binds to unpaired Vam3. Antibodies to a component of this complex inhibited in vitro vacuole-to-vacuole fusion. Furthermore, temperature-conditional mutations in the Class C VPS genes destabilized Vam3-Vti1-Vam7 pairing. Therefore, we propose that the C-Vps complex associates with unpaired (activated) Vam3 to mediate the assembly of trans-SNARE complexes during both vesicle docking/fusion and vacuole-to-vacuole fusion.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adaptor Proteins, Vesicular Transport
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Carrier Proteins*
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Cytoplasmic Vesicles / metabolism*
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Escherichia coli
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Fungal Proteins / genetics
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Fungal Proteins / metabolism*
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Gene Expression / physiology
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Golgi Apparatus / metabolism
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Membrane Fusion / physiology
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Membrane Proteins / genetics
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Membrane Proteins / metabolism*
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Munc18 Proteins
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Nerve Tissue Proteins / genetics
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Nerve Tissue Proteins / metabolism
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Protein Transport / physiology
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Qa-SNARE Proteins
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SNARE Proteins
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Saccharomyces cerevisiae Proteins*
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Synaptosomal-Associated Protein 25
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Vacuoles / metabolism*
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Vesicular Transport Proteins*
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Yeasts
Substances
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Adaptor Proteins, Vesicular Transport
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Carrier Proteins
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Fungal Proteins
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Membrane Proteins
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Munc18 Proteins
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Nerve Tissue Proteins
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PEP3 protein, S cerevisiae
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PEP5 protein, S cerevisiae
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Qa-SNARE Proteins
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SNARE Proteins
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Saccharomyces cerevisiae Proteins
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Synaptosomal-Associated Protein 25
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VAM3 protein, S cerevisiae
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VPS16 protein, S cerevisiae
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VPS33 protein, S cerevisiae
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Vesicular Transport Proteins