Defining the functions of trans-SNARE pairs.
The homotypic fusion of yeast vacuoles includes a 'docking' step, which we show here to consist of two sequential reactions: a reversible 'tethering' mediated by the GTPase Ypt7, and 'SNARE pairing', in which SNARE proteins from opposite membranes form a complex in trans. The function of this trans-SNARE complex must be transient, as the complex can be disassembled by excess Sec18 in the presence of Sec17 and ATP without influencing the fusion rate. These data indicate that SNARE pairing may transiently signal to downstream factors, leading to fusion.
Ungermann
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Dartmouth Medical School, Department of Biochemistry, Hanover, New Hampshire 03755, USA. Christian.Ungermann@Dartmouth.edu
Sato
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Wickner
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D000251:Adenosine Triphosphatases; D002352:Carrier Proteins / Q000502:physiology; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology; D019204:GTP-Binding Proteins / Q000502:physiology*; D020730:Guanine Nucleotide Dissociation Inhibitors; D007425:Intracellular Membranes / Q000502:physiology; D008561:Membrane Fusion / Q000502:physiology*; D008565:Membrane Proteins / Q000502:physiology*; D050765:Qa-SNARE Proteins; D050600:SNARE Proteins; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D014617:Vacuoles / Q000502:physiology*; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins
D002352:Carrier Proteins; D005656:Fungal Proteins; C086796:GDP dissociation inhibitor 1; D020730:Guanine Nucleotide Dissociation Inhibitors; D008565:Membrane Proteins; D050765:Qa-SNARE Proteins; C075137:SEC17 protein, S cerevisiae; D050600:SNARE Proteins; D029701:Saccharomyces cerevisiae Proteins; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; C107706:VAM3 protein, S cerevisiae; D033921:Vesicular Transport Proteins; D000251:Adenosine Triphosphatases; D019204:GTP-Binding Proteins; C064404:SEC18 protein, S cerevisiae; C079005:YPT7 protein, S cerevisiae; D020691:rab GTP-Binding Proteins