Tlg2p, a yeast syntaxin homolog that resides on the Golgi and endocytic structures

J Biol Chem. 1998 May 8;273(19):11719-27. doi: 10.1074/jbc.273.19.11719.

Abstract

Intracellular membrane fusion events in eukaryotic cells are thought to be mediated by protein-protein interactions between soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex proteins. We have identified and analyzed a new yeast syntaxin homolog, Tlg2p. Tlg2p is unique among known syntaxin family proteins in possessing a sizeable hydrophilic domain of 63 amino acids that is C-terminal to the membrane spanning region and nonessential for Tlg2p function. Tlg2p resides on the endosome and late Golgi by co-localization with an endocytic intermediate and co-fractionation with markers for both endosomes and late Golgi. Cells depleted for Tlg2p missort a portion of carboxypeptidase Y and are defective in endocytosis. In addition, we report that Tlg2p forms a SEC18-dependent SNARE complex with Snc2p, a vesicle SNARE known to function in Golgi to plasma membrane trafficking. Based on these findings we propose that Tlg2p is a t-SNARE that functions in transport from the endosome to the late Golgi and on the endocytic pathway.

Publication types

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

MeSH terms

  • Adenosine Triphosphatases*
  • Amino Acid Sequence
  • Carboxypeptidases / metabolism
  • Cathepsin A
  • Cell Compartmentation
  • Endocytosis*
  • Fungal Proteins / chemistry
  • Fungal Proteins / metabolism
  • Fungal Proteins / physiology
  • Golgi Apparatus / metabolism*
  • Macromolecular Substances
  • Membrane Fusion
  • Membrane Proteins / chemistry
  • Membrane Proteins / physiology*
  • Membrane Transport Proteins*
  • Molecular Sequence Data
  • Mutagenesis, Insertional
  • Qa-SNARE Proteins
  • R-SNARE Proteins
  • Receptors, Cytoplasmic and Nuclear / metabolism*
  • Saccharomyces cerevisiae
  • Saccharomyces cerevisiae Proteins*
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Vesicular Transport Proteins*

Substances

  • Fungal Proteins
  • Macromolecular Substances
  • Membrane Proteins
  • Membrane Transport Proteins
  • PEP12 protein, S cerevisiae
  • Qa-SNARE Proteins
  • R-SNARE Proteins
  • Receptors, Cytoplasmic and Nuclear
  • SNC2 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • TLG2 protein, S cerevisiae
  • VAM3 protein, S cerevisiae
  • Vesicular Transport Proteins
  • Carboxypeptidases
  • Cathepsin A
  • Adenosine Triphosphatases
  • SEC18 protein, S cerevisiae