Characterization of the human GARP (Golgi associated retrograde protein) complex
- Medical Department I, University of the Saarland, Homburg 66421 (Germany)
- Department of Obstetrics and Gynecology, University of Kiel, 24105 Kiel (Germany)
- Burnham Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037 (United States)
- Department of Histology and Embryology, Nanning, Guangxi 530021 (China)
- Department of Biochemistry, University of the Saarland, Homburg 66421 (Germany)
The Golgi associated retrograde protein complex (GARP) 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 Trans Golgi Network area. This is in accordance with a putative role in Golgi associated transport processes. In Saccharomyces cerevisiae, GARP 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 GARP mediated by hVps52. This reveals a previously unknown function of human Syntaxin 10 in membrane docking and fusion events at the Golgi. Taken together, GARP shows significant conservation between various species but diversification and specialization result in important differences in human cells.
- OSTI ID:
- 20717595
- Journal Information:
- Experimental Cell Research, Vol. 306, Issue 1; Other Information: DOI: 10.1016/j.yexcr.2005.01.022; PII: S0014-4827(05)00037-6; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0014-4827
- Country of Publication:
- United States
- Language:
- English
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