Cog3p depletion blocks vesicle-mediated Golgi retrograde trafficking in HeLa cells

• Published in: The Journal of cell biology Vol. 168; no. 5; pp. 747 - 759
• Main Authors: Zolov, Sergey N, Lupashin, Vladimir V
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 28.02.2005; The Rockefeller University Press
• Subjects: Adaptor Proteins, Vesicular Transport - deficiency; Adaptor Proteins, Vesicular Transport - metabolism; Animals; Antibodies; Cell membranes; Cells; Cellular biology; CHO cells; Coat Protein Complex I - metabolism; Cogs; Cytoplasmic Vesicles - metabolism; Cytoplasmic Vesicles - ultrastructure; Endoplasmic Reticulum - ultrastructure; Golgi apparatus; Golgi Apparatus - metabolism; Golgi Apparatus - ultrastructure; HeLa Cells; Humans; Membrane Glycoproteins - metabolism; Mice; Microscopy, Electron; P branes; Phosphoproteins - metabolism; Protein Transport - physiology; Proteins; Saccharomyces cerevisiae Proteins; Shiga Toxin - metabolism; Small interfering RNA; SNARE Proteins; Transfection; Vesicular Transport Proteins - metabolism; Yeasts
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.200412003

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.