N-linked glycosylation is not required for Na+/glucose symport activity in LLC-PK1 cells.
The role of N-linked glycosylation in Na+/glucose symporter function was investigated using LLC-PK1 cell cultures. Tunicamycin treatment did not inhibit Na(+)-dependent glucose transport or phlorizin binding activity assayed in intact LLC-PK1 cells. However apical membrane vesicles derived from tunicamycin-treated cells had no detectable Na(+)-dependent glucose transport activity but retained unchanged phlorizin binding to the symporter. These observations suggest that N-linked glycosylation is not required for transport function or insertion in the membrane in intact cells but may play a role in maintaining symporter transport activity in isolated membranes.
Wu
J S
JS
Department of Biochemistry and Molecular Biology, University of Texas Medical School at Houston 77225.
Lever
J E
JE
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D002469:Cell Separation; D006031:Glycosylation; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D010695:Phlorhizin / Q000378:metabolism; D051269:Sodium-Glucose Transporter 1; D013552:Swine; D014415:Tunicamycin / Q000494:pharmacology
D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D051269:Sodium-Glucose Transporter 1; D014415:Tunicamycin; D010695:Phlorhizin