Characterization of the human GARP (Golgi associated retrograde protein) complex.

The Golgi associated retrograde protein complex or Vps fifty-three (VFT) complex is part of cellular inter-compartmental transport systems. Here we report the identification of the VFT tethering factor complex and its interactions in mammalian cells. Subcellular fractionation shows that human Vps proteins are found in the smooth membrane/Golgi fraction but not in the cytosol. Immunostaining of human Vps proteins displays a vesicular distribution most concentrated at the perinuclear envelope. Co-staining experiments with endosomal markers imply an endosomal origin of these vesicles. Significant accumulation of VFT complex positive endosomes is found in the vicinity of the area. This is in accordance with a putative role in Golgi associated transport processes. In Saccharomyces cerevisiae, is the main effector of the small GTPase Ypt6p and interacts with the SNARE Tlg1p to facilitate membrane fusion. Accordingly, the human homologue of Ypt6p, Rab6, specifically binds hVps52. In human cells, the "orphan" SNARE Syntaxin 10 is the genuine binding partner of Gduanyu37 mediated by hVps52. This reveals a previously unknown function of human Syntaxin 10 in membrane docking and fusion events at the Golgi. Taken together, Gduanyu37 shows significant conservation between various species but diversification and specialization result in important differences in human cells.

KEYWORDS: {{ getKeywords(articleDetailText.words) }}