Glucose transport activity and ligand binding (cytochalasin B, IAPS-forskolin) of chimeric constructs of GLUT2 and GLUT4 expressed in COS-7-cells.
Chimeric constructs of glucose transporters GLUT2 and GLUT4 were transiently expressed in COS-7 cells in order to determine regions of the proteins responsible for their differences in activity and ligand binding. Exchange of the C-terminal tail (aa 479-509) of GLUT4 failed to affect glucose transport activity assayed at 1 mM glucose or ligand binding (cytochalasin B, IAPS-forskolin). In contrast, exchange of the C-terminal half of GLUT4 (aa 222-509) for that of GLUT2 markedly reduced ligand binding (Kd of cytochalasin B binding 1.88 +/- 0.2 microM vs. 0.21 +/- 0.06 in the wild-type GLUT4), and moderately (25%) reduced glucose transport activity. These data support the conclusion that the domains determining differences in ligand binding between GLUT4 and GLUT2 are located in the C-terminal half of the glucose transporters.
Wandel
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S
Institut für Pharmakologie und Toxikologie der RWTH, Aachen, Germany.
Buchs
A
A
Schürmann
A
A
Summers
S A
SA
Powers
A C
AC
Shanahan
M F
MF
Joost
H G
HG
D000818:Animals; D001386:Azides / Q000378:metabolism*; D001665:Binding Sites; D001692:Biological Transport; D019556:COS Cells; D005576:Colforsin / Q000031:analogs & derivatives* / Q000378:metabolism; D003571:Cytochalasin B / Q000378:metabolism*; D004224:Diterpenes; D018014:Gene Transfer Techniques; D005947:Glucose / Q000378:metabolism*; D051273:Glucose Transporter Type 2; D051275:Glucose Transporter Type 4; D008024:Ligands; D009004:Monosaccharide Transport Proteins / Q000235:genetics* / Q000378:metabolism; D009124:Muscle Proteins; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism*
D001386:Azides; D004224:Diterpenes; D051273:Glucose Transporter Type 2; D051275:Glucose Transporter Type 4; D008024:Ligands; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D011993:Recombinant Fusion Proteins; C054433:3-iodo-4-azidophenethylamido-7-O-succinyldeacetylforskolin; D005576:Colforsin; D003571:Cytochalasin B; D005947:Glucose