N-glycosylation and deletion mutants of the human MDR1 P-glycoprotein

Alfred H. Schinkel, Stephan Kemp, Martijn Dollé, Gabrielle Rudenko, Els Wagenaar

Research output: Contribution to journalArticle

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Abstract

P-glycoproteins are heavily glycosylated plasma membrane proteins, which confer multidrug resistance by pumping a range of different drugs from the cell. To investigate the significance of the conserved N-glycosylation sites present in the putative first extracellular loop of P-glycoproteins, we mutated one, two, or all three of these sites present in the human MDR1 P-glycoprotein. We also deleted a stretch of 20 amino acids, containing two of the three N-glycosylation sites. The effects of these mutations were studied by transfection into drug-sensitive cells. In vincristine-resistant transfected clones selected for similar steady state levels of membrane-bound P-glycoprotein, the absence of N-glycosylation did not alter the level or pattern of (cross-)resistance. However, the absence of N-glycosylation sites drastically reduced the efficiency with which drug-resistant clones could be generated. These findings suggest that N-glycosylation contributes to proper routing or stability of P-glycoprotein but not to drug transport per se. The deletion mutants demonstrated a clearly decreased and altered drug resistance pattern, even with a high level of P-glycoprotein in the plasma membrane. This, and possibly the observed lack of glycosylation of the remaining intact glycosylation sequence, suggests a constrained P-glycoprotein structure. Our findings support the current model for P-glycoprotein structure.

Original languageEnglish (US)
Pages (from-to)7474-7481
Number of pages8
JournalJournal of Biological Chemistry
Volume268
Issue number10
StatePublished - Apr 5 1993
Externally publishedYes

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Glycosylation
P-Glycoprotein
P-Glycoproteins
Pharmaceutical Preparations
Cell membranes
Clone Cells
Cell Membrane
Multiple Drug Resistance
Vincristine
Drug Resistance
Transfection
Blood Proteins
Membrane Proteins
Membranes
Amino Acids
Mutation

ASJC Scopus subject areas

  • Biochemistry

Cite this

Schinkel, A. H., Kemp, S., Dollé, M., Rudenko, G., & Wagenaar, E. (1993). N-glycosylation and deletion mutants of the human MDR1 P-glycoprotein. Journal of Biological Chemistry, 268(10), 7474-7481.

N-glycosylation and deletion mutants of the human MDR1 P-glycoprotein. / Schinkel, Alfred H.; Kemp, Stephan; Dollé, Martijn; Rudenko, Gabrielle; Wagenaar, Els.

In: Journal of Biological Chemistry, Vol. 268, No. 10, 05.04.1993, p. 7474-7481.

Research output: Contribution to journalArticle

Schinkel, AH, Kemp, S, Dollé, M, Rudenko, G & Wagenaar, E 1993, 'N-glycosylation and deletion mutants of the human MDR1 P-glycoprotein', Journal of Biological Chemistry, vol. 268, no. 10, pp. 7474-7481.
Schinkel AH, Kemp S, Dollé M, Rudenko G, Wagenaar E. N-glycosylation and deletion mutants of the human MDR1 P-glycoprotein. Journal of Biological Chemistry. 1993 Apr 5;268(10):7474-7481.
Schinkel, Alfred H. ; Kemp, Stephan ; Dollé, Martijn ; Rudenko, Gabrielle ; Wagenaar, Els. / N-glycosylation and deletion mutants of the human MDR1 P-glycoprotein. In: Journal of Biological Chemistry. 1993 ; Vol. 268, No. 10. pp. 7474-7481.
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