The docking stage of yeast vacuole fusion requires the transfer of proteins from a cis-SNARE complex to a Rab/Ypt protein

J Cell Biol. 2000 Mar 20;148(6):1231-8. doi: 10.1083/jcb.148.6.1231.

Abstract

The homotypic fusion of yeast vacuoles requires Sec18p (NSF)-driven priming to allow vacuole docking, but the mechanism that links priming and docking is unknown. We find that a large multisubunit protein called the Vam2/6p complex is bound to cis-paired SNAP receptors (SNAREs) on isolated vacuoles. This association of the Vam2/6p complex with the cis-SNARE complex is disrupted during priming. The Vam2/6p complex then binds to Ypt7p, a guanosine triphosphate binding protein of the Rab family, to initiate productive contact between vacuoles. Thus, cis-SNARE complexes can contain Rab/Ypt effectors, and these effectors can be mobilized by NSF/Sec18p-driven priming, allowing their direct association with a Rab/Ypt protein to activate docking.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adaptor Proteins, Vesicular Transport
  • Adenosine Triphosphatases*
  • Carrier Proteins / isolation & purification
  • Carrier Proteins / physiology
  • Fungal Proteins / physiology
  • Membrane Fusion / physiology*
  • Membrane Proteins / isolation & purification
  • Membrane Proteins / physiology*
  • Models, Biological
  • Nuclear Proteins*
  • RNA-Binding Proteins / isolation & purification
  • RNA-Binding Proteins / physiology
  • SNARE Proteins
  • Saccharomyces cerevisiae / physiology*
  • Saccharomyces cerevisiae / ultrastructure
  • Saccharomyces cerevisiae Proteins*
  • Vacuoles / physiology*
  • Vacuoles / ultrastructure
  • Vesicular Transport Proteins*
  • rab GTP-Binding Proteins / physiology*

Substances

  • Adaptor Proteins, Vesicular Transport
  • Carrier Proteins
  • Fungal Proteins
  • Membrane Proteins
  • NPL3 protein, S cerevisiae
  • Nuclear Proteins
  • RNA-Binding Proteins
  • SNARE Proteins
  • Saccharomyces cerevisiae Proteins
  • VAM6 protein, S cerevisiae
  • VPS41 protein, S cerevisiae
  • Vesicular Transport Proteins
  • Adenosine Triphosphatases
  • SEC18 protein, S cerevisiae
  • YPT7 protein, S cerevisiae
  • rab GTP-Binding Proteins