Structure and function of mammalian facilitative sugar transporters. J Biol Chem
Available from: Anton J M Wagenmakers
- "Leg glucose uptake increased threefold during the 4 h period following oral ingestion of 92 g of glucose (Katz et al. 1983), approximately fivefold during a hyperinsulinemic-euglycemic clamp (DeFronzo et al. 1985) and approximately 15-fold during exercise at 50–60% VO 2 max (Katz et al. 1986; Martin et al. 1995). Glucose is transported into the muscle cell via facilitated transport through glucose transporter proteins in the plasma membrane (PM) and T-tubule membranes (Bell et al. 1993). Glucose transporter 4 (GLUT4) is an insulin and contraction responsive glucose transporter and is the major glucose transporter isoform expressed in skeletal muscle (Mueckler 1994; Gaster et al. 2000). "
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ABSTRACT: Insulin- and contraction-stimulated increases in glucose uptake into skeletal muscle occur in part as a result of the translocation of glucose transporter 4 (GLUT4) from intracellular stores to the plasma membrane (PM). This study aimed to use immunofluorescence microscopy in human skeletal muscle to quantify GLUT4 redistribution from intracellular stores to the PM in response to glucose feeding and exercise. Percutaneous muscle biopsy samples were taken from the m. vastus lateralis of ten insulin-sensitive men in the basal state and following 30 min of cycling exercise (65% VO2 max). Muscle biopsy samples were also taken from a second cohort of ten age-, BMI- and VO2 max-matched insulin-sensitive men in the basal state and 30 and 60 min following glucose feeding (75 g glucose). GLUT4 and dystrophin colocalization, measured using the Pearson's correlation coefficient, was increased following 30 min of cycling exercise (baseline r = 0.47 ± 0.01; post exercise r = 0.58 ± 0.02; P < 0.001) and 30 min after glucose ingestion (baseline r = 0.42 ± 0.02; 30 min r = 0.46 ± 0.02; P < 0.05). Large and small GLUT4 clusters were partially depleted following 30 min cycling exercise, but not 30 min after glucose feeding. This study has, for the first time, used immunofluorescence microscopy in human skeletal muscle to quantify increases in GLUT4 and dystrophin colocalization and depletion of GLUT4 from large and smaller clusters as evidence of net GLUT4 translocation to the PM.
© 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.
- "FDG is transported into cells by glucose transporters and is phosphorylated by hexokinase enzyme to 18F-2-FDG-6 phosphate but is not metabolized. The degree of cellular FDG uptake is related to the cellular metabolic rate and the number of glucose transporters [94–96]. Activated inflammatory cells also demonstrate increased expression of glucose transporters. "
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ABSTRACT: Nuclear medicine imaging techniques offer whole body imaging for localization of number and site of infective foci inspite of limitation of spatial resolution. The innate human immune system contains a large member of important elements including antimicrobial peptides to combat any form of infection. However, development of antibiotics against bacteria progressed rapidly and gained popularity over antimicrobial peptides but even powerful antimicrobials failed to reduce morbidity and mortality due to emergence of mutant strains of bacteria resulting in antimicrobial resistance. Differentiation between infection and inflammation using radiolabeled compounds with nuclear medicine techniques has always been a dilemma which is still to be resolved. Starting from nonspecific tracers to specific radiolabeled tracers, the question is still unanswered. Specific radiolabeled tracers included antibiotics and antimicrobial peptides which bind directly to the bacteria for efficient localization with advanced nuclear medicine equipments. However, there are merits and demerits attributed to each. In the current paper, radiolabeled antibiotics and radiolabeled peptides for infection localization have been discussed starting with the background of primitive nonspecific tracers. Radiolabeled antimicrobial peptides have certain merits compared with labeled antibiotics which make them superior agents for localization of infective focus.
Available from: Kang Chong
- "predicted 10–12 transmembrane domains, and TopPred (http://mobyle.pasteur.fr/cgi-bin/portal.py? form¼toppred) predicted 12 hydrophobic transmembrane domains with a hydrophobicity value above 1.0 (Fig. 1A, double-arrow lines) arranged in two sets separated by a central hydrophilic loop (Fig. 1C). The transmembrane topology structure is consistent with the monosaccharide transporters in plants (Bush, 1999), yeast (Bisson et al., 1993), and mammals (Bell et al., 1993). Phylogenetic analysis (Fig. 1B) shows that the putative Arabidopsis paralogues to OsGMST1 are encoded by At1g67300, SGB1, At1g05030, and AtpGlcT and the proteins have 67%, 65%, 44%, and 43% identity to OsGMST1, respectively. "
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ABSTRACT: Sugar transport is critical for normal plant development and stress responses. However, functional evidence for the roles
of monosaccharide transporters in rice (Oryza sativa) has not previously been presented. In this study, reversed genetics was used to identify OsGMST1 as a member of the monosaccharide
transporter family in rice. The predicted 481 amino acid protein has the typical features of a sugar transporter in the plastid
glucose transporter subfamily consistent with reduced monosaccharide accumulation in plants with reduced OsGMST1 expression. OsGMST1-green fluorescent protein is localized to the Golgi apparatus. OsGMST1 expression is induced by salt treatment and reduced expression confers hypersensitivity to salt stress in rice. OsGMST1 may
play a direct or an indirect role in tolerance to salt stress in rice.
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