ISSN:
1432-1912
Keywords:
Key words Glucose transport
;
IAPS-forskolin
;
Insulin-regulated glucose transporter GLUT4
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Two arginine residues (RR333/334) in the conserved GRR motif located in the endofacial loop between helix 8 and 9 of the glucose transporter GLUT4 were substituted for leucine and alanine, respectively. Reconstituted glucose transport activity of the construct (GLUT4-RR333/4LA) expressed in COS-7 or LM(TK–) cells was less than 10% of that of the wild-type GLUT4. In contrast, binding of the inhibitory ligand cytochalasin B and glucose-inhibitable photolabeling with IAPS-forskolin were not significantly affected. Exchange of a histidine residue (H337Q) previously believed to be involved in the binding of inhibitory ligands failed to affect any of the investigated parameters. These data suggest that positive charges in the GRR motif at the cytoplasmic surface of the transporter participate in the conformational changes of the carrier protein during the process of facilitated diffusion.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00168913
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