Molecular mechanisms of the increased glucose transport in transformed FRTL-5 rat thyroid cells.
We investigated the molecular mechanisms involved in the glucose carrier (Glut 1) regulation in FRTL-5 cells and two derived transformed clones (SRC and Ki-Mol cells). When compared to the wild-type strain, SRC and Ki-Mol cells showed an increase in both glucose consumption and uptake (about 60 fold), associated with 6-8 fold higher Glut 1 mRNA levels. Transcriptional studies revealed a 2- to 3 fold increased activation of the gene in the transformed cells, suggesting that transcription alone cannot fully account for the higher Glut 1 gene expression. Western blot studies showed an increase of the Glut 1 protein in SRC and Ki-Mol cells, associated with a different gel migration pattern and a disparate distribution rate between the plasma membrane and the microsomal fraction. These data indicate that the higher rate of glucose uptake observed in SRC and Ki-Mol cells is associated to an increase in Glut 1 gene expression, and that also changes in the subcellular distribution and probably in the structure of Glut 1 protein are present.
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Dipartimento di Medicina Clinica e Sperimentale, Università di Reggio Calabria, Catanzaro, Italy.
Damante
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Russo
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Distefano
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Grasso
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Fusco
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D000818:Animals; D001692:Biological Transport; D015152:Blotting, Northern; D002461:Cell Line, Transformed; D002467:Cell Nucleus / Q000378:metabolism; D002999:Clone Cells; D003847:Deoxyglucose / Q000378:metabolism; D015870:Gene Expression; D005947:Glucose / Q000378:metabolism*; D007700:Kinetics; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D013347:Subcellular Fractions / Q000378:metabolism; D013961:Thyroid Gland / Q000378:metabolism*; D014158:Transcription, Genetic
D009004:Monosaccharide Transport Proteins; D012333:RNA, Messenger; D003847:Deoxyglucose; D005947:Glucose