Translocation of FGF2 to the cell surface without release into conditioned media
| Autor: | Robert Z. Florkiewicz, Andrew Baird, Claude Trudel, Violaine Faure-Desire |
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| Rok vydání: | 2000 |
| Předmět: |
Physiology
medicine.medical_treatment Clinical Biochemistry Basic fibroblast growth factor Cell Biology Transfection Extracellular matrix Cell membrane chemistry.chemical_compound medicine Animals Viability assay Ouabain COS cells integumentary system Growth factor Cell Membrane Biological Transport Cell Biology Cell biology medicine.anatomical_structure chemistry Culture Media Conditioned COS Cells embryonic structures Fibroblast Growth Factor 2 biological phenomena cell phenomena and immunity |
| Zdroj: | Journal of Cellular Physiology. 185:260-268 |
| ISSN: | 1097-4652 0021-9541 |
| Popis: | Like most cells in culture, stably transfected COS-1 cells (CF18) that constitutively overexpress basic fibroblast growth factor (FGF2) do not release the growth factor into conditioned media. Yet, when cells were biotinylated, 30% of the total cell-associated immunoreactive FGF2 was detected on the cell surface. Under similar conditions, up to 70% of the total immunoreactive FGF2 in transfected endothelial cells (MAE ZIP) or untransfected rat (C6) and human (U87MG) glioblastoma cell lines was detected on their cell surface. When peripheral plasma membrane proteins were removed from the cell surface with 0.1 M sodium carbonate, the amount of exported FGF2 was significantly reduced, whereas cell viability was unaffected. FGF2 then reappeared on the cell surface in a time-dependent manner. Ouabain, a cardenolide previously shown to inhibit the export of FGF2 from transiently transfected COS-1 cells, blocked the appearance of FGF2 onto the surface of transfected CF18 cells and MAE ZIP cells but had no detectable effect on C6 and U87MG cells. The observation that the translocation of FGF2 onto the cell surface is dissociated from its release into conditioned medium is consistent with FGF2's being rarely found in biological fluids but always cell associated and in the extracellular matrix. The findings point to a role played by the protein export pathway in controlling FGF2 activity and the normal physiological function that this growth factor plays in cell growth and differentiation. The widely accepted presumption that the absence of FGF2 in conditioned media reflects its inability to exit the cell needs to be reevaluated. |
| Databáze: | OpenAIRE |
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