N-glycosylation of glucose transporter-1 (Glut-1) is associated with increased transporter affinity for glucose in human leukemic cells

Leuk Res. 1999 Apr;23(4):395-401. doi: 10.1016/s0145-2126(98)00179-9.


To elucidate the role of N-glycosylation in the functional activity of the universal glucose transporter, Glut-1, we investigated effects of the N-glycosylation inhibitor, tunicamycin, on glucose transport by human leukemic cell lines K562, U937 and HL60. Treatment with tunicamycin produced a 40-50% inhibition of 2-deoxyglucose uptake and this was associated with a 2-2.5-fold decrease in transporter affinity for glucose (Km) without a change in Vmax. Leukemic K562, U937 and HL60 cells expressed Glut-1 transporter protein. With K562 cells Glut-1 appeared as a broad band of 50-60 kDa, whereas with U937 and HL60 cells a diffuse band was observed at approximately 55 kDa. Treatment of K562 cells with tunicamycin for 18 h, resulted in extensive loss of the 50-60 kDa glycoprotein, appearance of a 30-40 kDa band and increased staining of a 45 kDa band. With U937 cells, tunicamycin treatment resulted in the appearance of a 30-40 kDa band and increased staining of a 45 kDa band. With HL60 cells loss of the 55 kDa Glut-1 band was observed and a band of 45 kDa appeared. Tunicamycin-treatment resulted in 75-90% inhibition in [3H]mannose incorporation but only 20-25% inhibition in [3H]thymidine and [3H]leucine incorporation. In contrast, tunicamycin had little effect on the viability and MTT responses of the cells used. These results suggest that in leukemic cells N-glycosylation of Glut-1 plays an important role in maintaining its structure and functional integration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3-O-Methylglucose / metabolism
  • 3-O-Methylglucose / pharmacokinetics
  • Cell Division / drug effects
  • Deoxyglucose / metabolism
  • Deoxyglucose / pharmacokinetics
  • Glucose / metabolism*
  • Glucose / pharmacokinetics
  • Glucose Transporter Type 1
  • Glycosylation / drug effects
  • HL-60 Cells
  • Humans
  • K562 Cells
  • Leukemia / metabolism*
  • Monosaccharide Transport Proteins / biosynthesis
  • Monosaccharide Transport Proteins / metabolism*
  • Tetrazolium Salts
  • Thiazoles
  • Tunicamycin / pharmacology
  • U937 Cells


  • Glucose Transporter Type 1
  • Monosaccharide Transport Proteins
  • SLC2A1 protein, human
  • Tetrazolium Salts
  • Thiazoles
  • Tunicamycin
  • 3-O-Methylglucose
  • Deoxyglucose
  • thiazolyl blue
  • Glucose