Glucose Deprivation Induces the Selective Accumulation of Hexose Transporter Protein GLUT-1 in the Plasma Membrane of Normal Rat Kidney Cells

Abstract

Antibody to the carboxyl-terminal of hexose transporter protein GLUT-1 was used to localize this carrier in normal rat kidney (NRK) cells during D-glucose (Glc) deprivation. Glc-deprivation of NRK cells induces increased hexose transport, inhibits the glycosylation of GLUT-1, and increases the content of both native, 55,000 apparent mol wt (Mr) and aglyco, 38,000 Mr GLUT-1 polypeptides. The distribution of GLUT-1 protein in subcellular fractions isolated from Glc-fed NRK cells shows that the 55,000 Mr polypeptide is most abundant in intracellular membrane fractions. Glc-fed cells that have been tunicamycin treated contain principally the 38,000 Mr GLUT-1 polypeptide, which is found predominantly in intracellular membrane fractions. In Glc-deprived cells the 55,000 Mr GLUT-1 polypeptide localizes predominantly in the Golgi and plasma membrane fractions, whereas the more abundant 38,000 Mr GLUT-1 polypeptide is distributed throughout all membrane fractions. In Glc-deprived but fructose-fed cells only the 55,000 Mr GLUT-1 polypeptide is detected, and it is found predominantly in the plasma membrane and Golgi fractions. The localization of GLUT-1 protein was directly and specifically visualized in NRK cells by immunofluorescence microscopy. Glc-fed cells show little labeling of cell borders and a small punctate juxtanuclear pattern suggestive of localization to the Golgi and, perhaps, endoplasmic reticulum. Glc-fed cells that have been tunicamycin treated show large punctate intracellular accumulations suggestive of localization to distended Golgi and perhaps endoplasmic reticulum. Glc-deprived cells exhibited intense labeling of cell borders as well as intracellular accumulations. Glc-deprived but fructose-fed cells show fewer intracellular accumulations, and the labeling is, in general, limited to the cell borders. Our results suggest that Glc deprivation induces the selective accumulation of GLUT-1 in the plasma membrane of NRK cells.

Evaluation of 2-deoxy-D-glucose as a chemotherapeutic agent: mechanism of cell death

“…In many normal cell types, glucose deprivation results in an increase in the maximum velocity of glucose transport (Kitzman et al, 1993). This has been attributed to one of several mechanisms; translocation of transporter from an intracellular compartment to the plasma membrane (Haspel et al, 1991), changes in the glycosylation pattern of the Glut1 transporter with decreased turnover of the protein (Macmahon and Frost, 1995), or by increased synthesis of m RNA and protein (Reed et al, 1990;von der Crone et al, 2000). For example, pre-adipocyte cell lines respond to glucose starvation by increasing transporter expression reflected in elevated levels of Glut1 transporter mRNA and protein (Reed et al, 1990).…”

Effects of 2‐deoxy‐D‐glucose on the functional state of the rat myoblast GLUT 1 transporter

“…before harvesting [8]. Cells were then labelled with [35S]-methionine, and subject to immunoprecipitation using rabbit anti-GLUT 1 Ab.…”

“…Post-translational modification of the GLUT 1 transporter ---The observed reduced GLUT 1 transport affinity could be due to deglycosylation of the GLUT 1 transporter, dGlc is known to be a potent inhibitor of protein glycosylation [29,30], and deglycosylated GLUT 1 transporter has been shown to exhibit reduced transport affinity [6][7][8]. Unglycosylated GLUT 1 transporter in Chinese Hamster Ovary cells [6], rat L6 myoblasts [7] and in rat kidney cells [8] has a size of around 38 kDa.…”

“…Unglycosylated GLUT 1 transporter in Chinese Hamster Ovary cells [6], rat L6 myoblasts [7] and in rat kidney cells [8] has a size of around 38 kDa.…”

The Na+/glucose cotransporters: from genes to therapy

“…The SGLT1 mRNA remains unchanged, whereas the GLUT1 protein strongly increases (38). This may be explained by the intracellular glucose concentration (39), which could be very low in S3 epithelial cells. Since the high filtration rate of sodium provides almost complete glucose reabsorption in S1 segments, no substrate would be available for reabsorption in the S3 territory.…”