Class C Vps Protein Complex Regulates Vacuolar SNARE Pairing and Is Required for Vesicle Docking/Fusion
2000; Elsevier BV; Volume: 6; Issue: 3 Linguagem: Inglês
10.1016/s1097-2765(00)00064-2
ISSN1097-4164
AutoresTrey K. Sato, Peter Rehling, Michael R. Peterson, Scott D. Emr,
Tópico(s)Lipid Membrane Structure and Behavior
ResumoAbstract 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.
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