Sugar transport in normal and Rous sarcoma virus-transformed chick-embryo fibroblasts.
3-O-methylglucose (3-OMeG) is a nonmetabolizable glucose analog and is, therefore, suitable for transport studies. 3-OMeG and glucose compete for entry into normal and Rous sarcoma virus (RSV)-transformed chick-embryo fibroblasts. Therefore, 3-OMeG can be used to study the transport of glucose in these cells. Chickembryo fibroblasts infected and transformed by RSV take up 3-OMeG at a faster rate than uninfected cells when both cell types are growing at the same rate. The rate of efflux of 3-OMeG also increases after transformation. When the uptake and the efflux reach a steady state, the intracellular concentration of 3-OMeG is equal to the concentration in the medium. This finding indicates that glucose is transported across the plasma membrane by facilitated diffusion. The V(max) of the transport system for 3-OMeG increases after transformation, while the affinity or K(m) of the system remains unchanged. We conclude that viral transformation causes a change in the plasma membrane of the infected cells by increasing either the number of molecules or the mobility of the glucose carrier.
D000818:Animals; D001358:Avian Sarcoma Viruses; D001692:Biological Transport; D002455:Cell Division; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D002642:Chick Embryo; D004247:DNA / Q000096:biosynthesis; D004273:DNA, Neoplasm / Q000096:biosynthesis; D005347:Fibroblasts / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D006601:Hexoses / Q000378:metabolism*; D007700:Kinetics; D008738:Methyl Ethers / Q000378:metabolism; D014316:Tritium
D004273:DNA, Neoplasm; D006601:Hexoses; D008738:Methyl Ethers; D014316:Tritium; D004247:DNA; D005947:Glucose