Role of Conserved Oligomeric Golgi Complex in the Abnormalities of Glycoprotein Processing in Breast Cancer Cells
Annual summary rept. 1 May 2003-30 Apr 2006
ARKANSAS UNIV AT LITTLE ROCK
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The conserved oligomeric Golgi COG complex consists of eight subunits that are thought to be involved in vesicle tethering. Available mutants with the mutations in COG complex subunits exhibit defects in basic Golgi functions protein glycosylation and its sorting. For analysis of COG complex function we utilized RNA interference assay to knockdown COG3p subunit of COG complex in normal and breast cancer cells and other tumor cell lines. Acute knockdown of the COG3 was accompanied by reduction in Cogi 2 and 4 protein levels rapid Golgi fragmentation and accumulation of COG complex dependent CCD vesicles. Constantly cycling medial-Golgi enzymes are transported from distal compartments in CCD vesicles. Dysfunction of COG complex leads to separation of glycosyltransferases from anterograde cargo molecules passing along secretory pathway thus affecting normal protein glycosylation. Altered level of COG3p or COG complex expression could be a common feature of cancer cells defective in protein trafficking and Golgi modifications. The importance of the COG complex for both function and architecture of the Golgi apparatus does not depend on cell type. Partial malfunction of the COG complex may play a role in establishing of cancer phenotype.
- Medicine and Medical Research