Alteration by transforming growth factor-beta 1 of asparagine-linked sugar chains in glucose transporter protein in Swiss 3T3 cells.
GLUT1 protein in Swiss 3T3 cells is a 55-kDa glycoprotein with an N-linked oligosaccharide chain. We previously showed that the 65-kDa GLUT1 protein with modulated glycosylation was induced by transforming growth factor-beta 1 (TGF-beta 1) in Swiss 3T3 cells. To further investigate the altered structures of these sugar chains, the membrane glycoproteins solubilized with Triton X-100 were fractionated by lectin-affinity chromatography. The 55-kDa GLUT1 in control and TGF-beta 1-treated cells showed partial binding to Datura stramonium agglutinin (DSA), whereas the 65-kDa GLUT1 exclusively bound to DSA- and wheat germ agglutinin (WGA)-agarose. The 65-kDa GLUT1 in TGF-beta 1-treated cells was sensitive to endo-beta-galactosidase, which cleaves unsubstituted polylactosamine chains. While the 55-kDa GLUT1 in control 3T3 cells was similarly digested by endo-beta-galactosidase, that in TGF-beta 1-treated cells was resistant to this enzyme. These results suggest that the N-linked oligosaccharides of GLUT1 in Swiss 3T3 cells were altered by TGF-beta 1 to forms with more branched and/or repeated polylactosamines as well as with some substitution in the polylactosamines, resulting in a larger GLUT1 molecule. These GLUT1 proteins were exclusively located at the plasma membrane and served as a glucose transporter. However, the affinity to 2-deoxyglucose was significantly increased by TGF-beta 1, associated with the altered glycosylation of GLUT1 protein.
Masumi
A
A
Department of Biochemistry and Cell Biology, National Institute of Health, Tokyo, Japan.
Akamatsu
Y
Y
Kitagawa
T
T
D016475:3T3 Cells; D000818:Animals; D001216:Asparagine / Q000737:chemistry*; D002462:Cell Membrane / Q000378:metabolism; D003847:Deoxyglucose / Q000378:metabolism; D005947:Glucose / Q000737:chemistry*; D051272:Glucose Transporter Type 1; D006026:Glycoside Hydrolases; D006031:Glycosylation / Q000187:drug effects; D007700:Kinetics; D051379:Mice; D009004:Monosaccharide Transport Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D009844:Oligosaccharides / Q000737:chemistry; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D051272:Glucose Transporter Type 1; D009004:Monosaccharide Transport Proteins; D009844:Oligosaccharides; C495678:Slc2a1 protein, mouse; D016212:Transforming Growth Factor beta; D001216:Asparagine; D003847:Deoxyglucose; D006026:Glycoside Hydrolases; D005947:Glucose