Proteins needed for vesicle budding from the Golgi complex are also required for the docking step of homotypic vacuole fusion.
Vam2p/Vps41p is known to be required for transport vesicles with vacuolar cargo to bud from the Golgi. Like other VAM-encoded proteins, which are needed for homotypic vacuole fusion, we now report that Vam2p and its associated protein Vam6p/Vps39p are needed on each vacuole partner for homotypic fusion. In vitro vacuole fusion occurs in successive steps of priming, docking, and membrane fusion. While priming does not require Vam2p or Vam6p, the functions of these two proteins cannot be fulfilled until priming has occurred, and each is required for the docking reaction which culminates in trans-SNARE pairing. Consistent with their dual function in Golgi vesicle budding and homotypic fusion of vacuoles, approximately half of the Vam2p and Vam6p of the cell are recovered from cell lysates with purified vacuoles.
Price
A
A
Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755-3844, USA.
Wickner
W
W
Ungermann
C
C
D033942:Adaptor Proteins, Vesicular Transport; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology; D006056:Golgi Apparatus / Q000502:physiology* / Q000648:ultrastructure*; D007700:Kinetics; D008561:Membrane Fusion / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D050600:SNARE Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins; D014617:Vacuoles / Q000502:physiology* / Q000648:ultrastructure; D033921:Vesicular Transport Proteins
D033942:Adaptor Proteins, Vesicular Transport; D002352:Carrier Proteins; D005656:Fungal Proteins; D008565:Membrane Proteins; C077734:NPL3 protein, S cerevisiae; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D050600:SNARE Proteins; D029701:Saccharomyces cerevisiae Proteins; C406817:VAM6 protein, S cerevisiae; C083878:VPS41 protein, S cerevisiae; D033921:Vesicular Transport Proteins