The role of N-glycosylation in the targeting and stability of GLUT1 glucose transporter.
The cDNAs encoding the GLUT1 glucose transporter protein were altered by site-directed mutagenesis at consensus sites for the addition of N-linked glycosylation. These cDNAs were transfected into CHO cells with an expression vector and the subcellular distribution and stability of the expressed glycosylation-defective GLUT1 protein were analyzed. Immunohistochemical analysis with a specific antibody demonstrated that a significant portion of glycosylation-defective GLUT1 protein remained in the intracellular compartment. By contrast, most of the wild-type GLUT1 protein expressed with the same procedures resided in the plasma membranes. Metabolic labeling studies revealed that the half-life of the glycosylation-defective GLUT1 protein was significantly shorter than that of wild-type GLUT1 protein. These results indicate that N-glycosylation of the glucose transporter affects its intracellular targeting and protein stability.
Asano
T
T
Third Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
Takata
K
K
Katagiri
H
H
Ishihara
H
H
Inukai
K
K
Anai
M
M
Hirano
H
H
Yazaki
Y
Y
Oka
Y
Y
D000818:Animals; D015153:Blotting, Western; D016466:CHO Cells; D006224:Cricetinae; D005455:Fluorescent Antibody Technique; D051272:Glucose Transporter Type 1; D006031:Glycosylation; D066298:In Vitro Techniques; D009004:Monosaccharide Transport Proteins / Q000737:chemistry / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000378:metabolism; D013329:Structure-Activity Relationship
D051272:Glucose Transporter Type 1; D009004:Monosaccharide Transport Proteins; D011994:Recombinant Proteins