Nucleotide-induced conformational changes in the human multidrug resistance protein MRP1 are related to the capacity of chemotherapeutic drugs to accumulate or not in resistant cells

FEBS Lett. 2001 Mar 23;493(1):31-5. doi: 10.1016/s0014-5793(01)02270-0.


Intracellular accumulation of anthracycline derivatives was measured in a human embryonic kidney cell line (HEK) and a resistant subline (HEK/multidrug resistance protein (MRP1)) overexpressing MRP1 at the plasma membrane surface. Two compounds (daunorubicin and doxorubicin) were rejected outside the multidrug-resistant cells. On the contrary, three compounds (4'-deoxy-4'-iodo-doxorubicin, 4-demethoxy-daunorubicin and 3'-(3-methoxymorpholino)doxorubicin) accumulated equally within sensitive HEK cells and resistant HEK/MRP1 cells. Our main objective here was to characterize the MRP1 conformational changes mediated by the binding of these anthracycline derivatives and to determine whether these conformational changes are related to MRP1-mediated drug transport. MRP1 was reconstituted in lipid vesicles as previously described [Manciu, L., Chang, X.B., Riordan, J.R. and Ruysschaert, J.-M. (2000) Biochemistry 39, 13026-13033]. The reconstituted protein was shown to conserve its ATPase and drug transport activity. Acrylamide quenching of Trp fluorescence was used to monitor drug-dependent conformational changes. Binding of drugs (4-demethoxy-daunorubicin and 3'-(3-methoxymorpholino)doxorubicin) which accumulate in resistant cells immobilizes MRP1 in a conformational state that is insensitive to ATP binding whereas drugs rejected outside the resistant cells (daunorubicin, doxorubicin) favor a conformational change which may be a required step in the transport process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP-Binding Cassette Transporters / chemistry*
  • ATP-Binding Cassette Transporters / metabolism*
  • Acrylamide / pharmacology
  • Adenosine Triphosphatases / metabolism
  • Antibiotics, Antineoplastic / pharmacology
  • Antineoplastic Agents / pharmacology
  • Binding Sites
  • Biological Transport
  • Catalytic Domain
  • Cell Line
  • Cell Membrane / metabolism
  • Daunorubicin / pharmacology
  • Dose-Response Relationship, Drug
  • Doxorubicin / pharmacology
  • Drug Resistance, Neoplasm*
  • Flow Cytometry
  • Humans
  • Kinetics
  • Models, Chemical
  • Multidrug Resistance-Associated Proteins
  • Protein Binding
  • Protein Conformation / drug effects


  • ATP-Binding Cassette Transporters
  • Antibiotics, Antineoplastic
  • Antineoplastic Agents
  • Multidrug Resistance-Associated Proteins
  • Acrylamide
  • Doxorubicin
  • Adenosine Triphosphatases
  • Daunorubicin