Role of Glut1 glucose transporter activation in stimulation of glucose transport by A231876 and TPA

1998 ◽  
Vol 26 (3) ◽  
pp. S289-S289
Author(s):  
Mehmet H. Koseoglu ◽  
F. Ismail Beigi
Keyword(s):  
Glucose Transport ◽  
Glucose Transporter ◽  
Glut1 Glucose Transporter ◽  
Stimulation Of

scholarly journals Trafficking of glucose transporters in 3T3-L1 cells. Inhibition of trafficking by phenylarsine oxide implicates a slow dissociation of transporters from trafficking proteins

1992 ◽  
Vol 281 (3) ◽  
pp. 809-817 ◽  
Author(s):  
J Yang ◽  
A E Clark ◽  
R Harrison ◽  
I J Kozka ◽  
G D Holman
Keyword(s):  
Cell Surface ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Fluid Phase ◽  
Transport Activity ◽  
Phenylarsine Oxide ◽  
Fluid Phase Endocytosis ◽  
Surface Labelling ◽  
Slow Dissociation ◽  
Stimulation Of

We have compared the rates of insulin stimulation of cell-surface availability of glucose-transporter isoforms (GLUT1 and GLUT4) and the stimulation of 2-deoxy-D-glucose transport in 3T3-L1 cells. The levels of cell-surface transporters have been assessed by using the bismannose compound 2-N-[4-(1-azi-2,2,2-trifluoroethyl)benzoyl]-1,3-bis(D-mannos -4-yloxy) propyl-2-amine (ATB-BMPA). At 27 degrees C the half-times for the appearance of GLUT1 and GLUT4 at the cell surface were 5.7 and 5.4 min respectively and were slightly shorter than that for the observed stimulation of transport activity (t 1/2 8.6 min). This lag may be due to a slow dissociation of surface transporters from trafficking proteins responsible for translocation. When fully-insulin-stimulated cells were subjected to a low-pH washing procedure to remove insulin at 37 degrees C, the cell-surface levels of GLUT1 and GLUT4 decreased, with half-times of 9.2 and 6.8 min respectively. These times correlated well with decrease in 2-deoxy-D-glucose transport activity that occurred during this washing procedure (t1/2 6.5 min). When fully-insulin-stimulated cells were treated with phenylarsine oxide (PAO), a similar decrease in transport activity occurred (t1/2 9.8 min). However, surface labelling showed that this corresponded with a decrease in GLUT4 only (t1/2 7.8 min). The cell-surface level of GLUT1 remained high throughout the PAO treatment. Light-microsome membranes were isolated from cells which had been cell-surface-labelled with ATB-BMPA. Internalization of both transporter isoforms to this pool occurred when cells were maintained in the presence of insulin for 60 min. In contrast with the surface-labelling results, we have shown that the transfer to the light-microsome pool of both transporters occurred in cells treated with insulin and PAO. These results suggest that both transporters are recycled by fluid-phase endocytosis and exocytosis. PAO may inhibit this recycling at a stage which involves the re-emergence of internalized transporters at the plasma membrane. The GLUT1 transporters that are recycled to the surface in insulin- and PAO-treated cells appear to have low transport activity. This may be because of a failure to dissociate fully from trafficking proteins at the cell surface. GLUT4 transporters appear to have a greater tendency to remain internalized if the normal mechanisms that commit transporters to the cell surface, such as dissociation from trafficking proteins, are uncoupled.

Effect of diet on insulin- and contraction-mediated glucose transport and uptake in rat muscle

1995 ◽  
Vol 269 (3) ◽  
pp. R544-R551 ◽  
Author(s):  
X. Han ◽  
T. Ploug ◽  
H. Galbo
Keyword(s):  
Glucose Uptake ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Fiber Types ◽  
Transport Capacity ◽  
Glut 1 ◽  
Glut 4 ◽  
Red Muscle ◽  
Muscle Glucose Transport ◽  
Stimulation Of

A diet rich in fat diminishes insulin-mediated glucose uptake in muscle. This study explored whether contraction-mediated glucose uptake is also affected. Rats were fed a diet rich in fat (FAT, 73% of energy) or carbohydrate (CHO, 66%) for 5 wk. Hindquarters were perfused, and either glucose uptake or glucose transport capacity (uptake of 3-O-[14C]-methyl-D-glucose (40 mM)) was measured. Amounts of glucose transporter isoform GLUT-1 and GLUT-4 glucose-transporting proteins were determined by Western blot. Glucose uptake was lower (P < 0.05) in hindlegs from FAT than from CHO rats at submaximum and maximum insulin [4 +/- 0.4 vs. 5 +/- 0.3 (SE) mumol.min-1.leg-1 at 150 microU/ml insulin] as well as during prolonged stimulation of the sciatic nerve (4.4 +/- 0.4 vs. 5.6 +/- 0.6 mumol.min-1.leg-1). Maximum glucose transport elicited by insulin (soleus: 1.7 +/- 0.2 vs. 2.6 +/- 0.2 mumol.g-1.5 min-1, P < 0.05) or contractions (soleus: 1.8 +/- 0.2 vs. 2.6 +/- 0.3, P < 0.05) in red muscle was decreased in parallel in FAT compared with CHO rats. GLUT-4 content was decreased by 13-29% (P < 0.05) in the various fiber types, whereas GLUT-1 content was identical in FAT compared with CHO rats. It is concluded that a FAT diet reduces both insulin and contraction stimulation of glucose uptake in muscle and that these effects are associated with diminished skeletal muscle glucose transport capacities and GLUT-4 contents.

scholarly journals Glucose Uptake in Trichoderma harzianum: Role of gtt1

2003 ◽  
Vol 2 (4) ◽  
pp. 708-717 ◽  
Author(s):  
Jesús Delgado-Jarana ◽  
Miguel Ángel Moreno-Mateos ◽  
Tahía Benítez
Keyword(s):  
Gene Expression ◽  
Glucose Uptake ◽  
Glucose Transport ◽  
Trichoderma Harzianum ◽  
Glucose Transporter ◽  
Biochemical Characterization ◽  
Carbon Sources ◽  
Low Carbon ◽  
Filamentous Ascomycete

ABSTRACT Using a differential display technique, the gene gtt1, which codes for a high-affinity glucose transporter, has been cloned from the mycoparasite fungus Trichoderma harzianum CECT 2413. The deduced protein sequence of the gtt1 gene shows the 12 transmembrane domains typical of sugar transporters, together with certain residues involved in glucose uptake, such as a conserved arginine between domains IV and V and an aromatic residue (Phe) in the sequence of domain X. The gtt1 gene is transcriptionally regulated, being repressed at high levels of glucose. When carbon sources other than glucose are utilized, gtt1 repression is partially alleviated. Full derepression of gtt1 is obtained when the fungus is grown in the presence of low carbon source concentrations. This regulation pattern correlates with the role of this gene in glucose uptake during carbon starvation. Gene expression is also controlled by pH, so that the gtt1 gene is repressed at pH 6 but not at pH 3, a fact which represents a novel aspect of the influence of pH on the gene expression of transporters. pH also affects glucose transport, since a strongly acidic pH provokes a 40% decrease in glucose transport velocity. Biochemical characterization of the transport shows a very low Km value for glucose (12 μM). A transformant strain that overexpresses the gtt1 gene shows a threefold increase in glucose but not galactose or xylose uptake, a finding which confirms the role of the gtt1 gene in glucose transport. The cloning of the first filamentous ascomycete glucose transporter is the first step in elucidating the mechanisms of glucose uptake and carbon repression in aerobic fungi.

scholarly journals Sorting of GLUT4 into its insulin-sensitive store requires the Sec1/Munc18 protein mVps45

2013 ◽  
Vol 24 (15) ◽  
pp. 2389-2397 ◽  
Author(s):  
Jennifer Roccisana ◽  
Jessica B. A. Sadler ◽  
Nia J. Bryant ◽  
Gwyn W. Gould
Keyword(s):  
Glucose Transport ◽  
Glucose Transporter ◽  
Vitro Assay ◽  
Protein Receptor ◽  
Storage Vesicles ◽  
Storage Vesicle ◽  
Impaired Insulin ◽  
Endosomal Pathway

Insulin stimulates glucose transport in fat and muscle cells by regulating delivery of the facilitative glucose transporter, glucose transporter isoform 4 (GLUT4), to the plasma membrane. In the absence of insulin, GLUT4 is sequestered away from the general recycling endosomal pathway into specialized vesicles, referred to as GLUT4-storage vesicles. Understanding the sorting of GLUT4 into this store is a major challenge. Here we examine the role of the Sec1/Munc18 protein mVps45 in GLUT4 trafficking. We show that mVps45 is up-regulated upon differentiation of 3T3-L1 fibroblasts into adipocytes and is expressed at stoichiometric levels with its cognate target–soluble N-ethylmaleimide–sensitive factor attachment protein receptor, syntaxin 16. Depletion of mVps45 in 3T3-L1 adipocytes results in decreased GLUT4 levels and impaired insulin-stimulated glucose transport. Using sub­cellular fractionation and an in vitro assay for GLUT4-storage vesicle formation, we show that mVps45 is required to correctly traffic GLUT4 into this compartment. Collectively our data reveal a crucial role for mVps45 in the delivery of GLUT4 into its specialized, insulin-regulated compartment.

scholarly journals Stimulation of glucose transport in Clone 9 cells by insulin and thyroid hormone: role of GLUT-1 activation

1996 ◽  
Vol 1314 (1-2) ◽  
pp. 140-146 ◽  
Author(s):  
Mangala Shetty ◽  
Ashok K Kuruvilla ◽  
Faramarz Ismail-Beigi ◽  
John N Loeb
Keyword(s):  
Thyroid Hormone ◽  
Glucose Transport ◽  
Glut 1 ◽  
Stimulation Of

Stimulation of glucose transport in skeletal muscle by hypoxia

1991 ◽  
Vol 70 (4) ◽  
pp. 1593-1600 ◽  
Author(s):  
G. D. Cartee ◽  
A. G. Douen ◽  
T. Ramlal ◽  
A. Klip ◽  
J. O. Holloszy
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Muscle Contraction ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Cytochalasin B ◽  
Sugar Transport ◽  
Transport Activity ◽  
Hindlimb Muscles ◽  
Stimulation Of

Hypoxia caused a progressive cytochalasin B-inhibitable increase in the rate of 3-O-methylglucose transport in rat epitrochlearis muscles to a level approximately six-fold above basal. Muscle ATP concentration was well maintained during hypoxia, and increased glucose transport activity was still present after 15 min of reoxygenation despite repletion of phosphocreatine. However, the increase in glucose transport activity completely reversed during a 180-min-long recovery in oxygenated medium. In perfused rat hindlimb muscles, hypoxia caused an increase in glucose transporters in the plasma membrane, suggesting that glucose transporter translocation plays a role in the stimulation of glucose transport by hypoxia. The maximal effects of hypoxia and insulin on glucose transport activity were additive, whereas the effects of exercise and hypoxia were not, providing evidence suggesting that hypoxia and exercise stimulate glucose transport by the same mechanism. Caffeine, at a concentration too low to cause muscle contraction or an increase in glucose transport by itself, markedly potentiated the effect of a submaximal hypoxic stimulus on sugar transport. Dantrolene significantly inhibited the hypoxia-induced increase in 3-O-methylglucose transport. These effects of caffeine and dantrolene suggest that Ca2+ plays a role in the stimulation of glucose transport by hypoxia.

Control of glucose transport by GLUT1: Regulated secretion in an unexpected environment

1995 ◽  
Vol 15 (6) ◽  
pp. 427-443 ◽  
Author(s):  
Christopher C. Widnell
Keyword(s):  
Plasma Membrane ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Standard Medium ◽  
Cytoplasmic Vesicles ◽  
Infected Cells ◽  
Vesicular Stomatitis ◽  
Cellular Stresses ◽  
Specific Membrane ◽  
Stimulation Of

Studies designed to elucidate the mechanism of regulation of the GLUT1 isoform of the glucose transporter in response to a variety of cellular stresses are reviewed. Using ts mutants of vesicular stomatitis virus, it was shown that the viral L gene was responsible for the stimulation of glucose transport in infected cells. Immunofluorescence of GLUT1 demonstrated that the increase in glucose transport was the consequence of a translocation of the transporter from a reservoir in cytoplasmic vesicles to the plasma membrane. When cells were cycled between deficient and standard medium, the change in glucose transport rates was paralleled by a cycling of the transporter between the plasma membrane and the cytoplasmic vesicles. The redistribution of GLUT1 was not a consequence of a general redistribution of recycling plasma membrane proteins. Instead, the findings focus attention on the regulated exocytosis of specific membrane constituents in cells that, until recently, were not thought to exhibit this capacity.

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