Yeast Vps45p is a Sec1p-like protein required for the consumption of vacuole-targeted, post-Golgi transport vesicles

Eur J Cell Biol. 1994 Dec;65(2):305-18.


Over 45 VPS genes (vacuolar protein sorting) in Saccharomyces cerevisiae are necessary for the correct sorting and delivery of vacuolar hydrolases. Yeast strains carrying mutations in a subset of these VPS genes (class D vps mutants) are also defective in the segregation of vacuolar material into the developing daughter cell and are morphologically characterized by having large central vacuoles. The class D VPS gene products, which include a Rab5 homologue (VPS21/YPT51) and a syntaxin homologue (PEP12/VPS6), have been proposed to function together at a particular step along the vacuolar protein sorting pathway. We have cloned another class D VPS gene, VPS45, which is homologous to a growing family of genes that encode Sec1p-like proteins. Vps45p is predicted to be a hydrophilic protein of 577 amino acids with a molecular mass of 67 kDa. Fractionation studies show that Vps45p is a peripheral membrane protein that cofractionates with Golgi-like membranes, consistent with Vps45p functioning in membrane traffic between the Golgi and the vacuole. Using a temperature-sensitive allele of VPS45, we show that inactivation of Vps45p causes the rapid accumulation of small (40-60 nm) vesicles and secretion of the vacuolar hydrolase carboxypeptidase Y. Because the entire yeast secretory pathway is functional after the temperature-induced inactivation of Vps45p, we conclude that the accumulated vesicles represent transport intermediates between the Golgi and the vacuole.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Biological Transport / physiology
  • Cloning, Molecular
  • Fungal Proteins / genetics*
  • Golgi Apparatus / metabolism*
  • Liposomes
  • Membrane Proteins / genetics
  • Molecular Sequence Data
  • Multigene Family*
  • Munc18 Proteins
  • Nerve Tissue Proteins*
  • Saccharomyces cerevisiae Proteins*
  • Sequence Homology, Amino Acid
  • Sequence Homology, Nucleic Acid
  • Temperature
  • Vacuoles / metabolism*
  • Vesicular Transport Proteins*


  • Fungal Proteins
  • Liposomes
  • Membrane Proteins
  • Munc18 Proteins
  • Nerve Tissue Proteins
  • Saccharomyces cerevisiae Proteins
  • VPS45 protein, S cerevisiae
  • Vesicular Transport Proteins

Associated data

  • GENBANK/L26088
  • GENBANK/M34638
  • GENBANK/S34207
  • GENBANK/U07972
  • GENBANK/X54323
  • GENBANK/X62451