1. Cog3p depletion blocks vesicle-mediated Golgi retrograde trafficking in HeLa cells.
- Author
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Zolov SN and Lupashin VV
- Subjects
- Adaptor Proteins, Vesicular Transport metabolism, Animals, Coat Protein Complex I metabolism, Cytoplasmic Vesicles ultrastructure, Endoplasmic Reticulum ultrastructure, Golgi Apparatus ultrastructure, HeLa Cells, Humans, Membrane Glycoproteins metabolism, Mice, Microscopy, Electron, Phosphoproteins metabolism, Protein Transport physiology, SNARE Proteins, Saccharomyces cerevisiae Proteins, Shiga Toxin metabolism, Vesicular Transport Proteins metabolism, Adaptor Proteins, Vesicular Transport deficiency, Cytoplasmic Vesicles metabolism, Golgi Apparatus metabolism
- Abstract
The conserved oligomeric Golgi (COG) complex is an evolutionarily conserved multi-subunit protein complex that regulates membrane trafficking in eukaryotic cells. In this work we used short interfering RNA strategy to achieve an efficient knockdown (KD) of Cog3p in HeLa cells. For the first time, we have demonstrated that Cog3p depletion is accompanied by reduction in Cog1, 2, and 4 protein levels and by accumulation of COG complex-dependent (CCD) vesicles carrying v-SNAREs GS15 and GS28 and cis-Golgi glycoprotein GPP130. Some of these CCD vesicles appeared to be vesicular coat complex I (COPI) coated. A prolonged block in CCD vesicles tethering is accompanied by extensive fragmentation of the Golgi ribbon. Fragmented Golgi membranes maintained their juxtanuclear localization, cisternal organization and are competent for the anterograde trafficking of vesicular stomatitis virus G protein to the plasma membrane. In a contrast, Cog3p KD resulted in inhibition of retrograde trafficking of the Shiga toxin. Furthermore, the mammalian COG complex physically interacts with GS28 and COPI and specifically binds to isolated CCD vesicles.
- Published
- 2005
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