Membrane cholesterol selectively modulates the activity of the human ABCG2 multidrug transporter

Ágnes Telbisz, M. Müller, C. Özvegy-Laczka, L. Homolya, Lajos Szente, A. Váradi, B. Sarkadi

Research output: Contribution to journalArticle

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Abstract

The human ABCG2 multidrug transporter provides protection against numerous toxic compounds and causes multidrug resistance in cancer. Here we examined the effects of changes in membrane cholesterol on the function of this protein. Human ABCG2 was expressed in mammalian and in Sf9 insect cells, and membrane cholesterol depletion or enrichment was achieved by preincubation with beta cyclodextrin or its cholesterol-loaded form. We found that mild cholesterol depletion of intact mammalian cells inhibited ABCG2-dependent dye and drug extrusion in a reversible fashion, while the membrane localization of the transporter protein was unchanged. Cholesterol enrichment of cholesterol-poor Sf9 cell membrane vesicles greatly increased ABCG2-driven substrate uptake, substrate-stimulated ATPase activity, as well as the formation of a catalytic cycle intermediate (nucleotide trapping). Interestingly, modulation of membrane cholesterol did not significantly affect the function of the R482G or R482T substrate mutant ABCG2 variants, or that of the MDR1 transporter. The selective, major effect of membrane cholesterol on the wild-type ABCG2 suggests a regulation of the activity of this multidrug transporter during processing or in membrane micro-domain interactions. The experimental recognition of physiological and pharmacological substrates of ABCG2, as well as the fight against cancer multidrug resistance may be facilitated by demonstrating the key role of membrane cholesterol in this transport activity.

Original languageEnglish
Pages (from-to)2698-2713
Number of pages16
JournalBBA - Biomembranes
Volume1768
Issue number11
DOIs
Publication statusPublished - Nov 2007

Fingerprint

Human Activities
Cholesterol
Membranes
Sf9 Cells
Multiple Drug Resistance
Substrates
Cell Membrane
ATP Binding Cassette Transporter, Sub-Family G, Member 2
Membrane Transport Proteins
Poisons
Cell membranes
Extrusion
Insects
Adenosine Triphosphatases
Neoplasms
Proteins
Coloring Agents
Nucleotides
Cells
Modulation

Keywords

  • ABC transporters
  • ABCG2 transport activity
  • ATPase activity
  • Membrane cholesterol
  • Multidrug resistance

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Biophysics

Cite this

Membrane cholesterol selectively modulates the activity of the human ABCG2 multidrug transporter. / Telbisz, Ágnes; Müller, M.; Özvegy-Laczka, C.; Homolya, L.; Szente, Lajos; Váradi, A.; Sarkadi, B.

In: BBA - Biomembranes, Vol. 1768, No. 11, 11.2007, p. 2698-2713.

Research output: Contribution to journalArticle

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