Multiple drugs compete for transport via the Plasmodium falciparum chloroquine resistance transporter at distinct but interdependent sites.
Mutations in the "chloroquine resistance transporter" (PfCRT) are a major determinant of drug resistance in the malaria parasite Plasmodium falciparum. We have previously shown that mutant PfCRT transports the antimalarial drug chloroquine away from its target, whereas the wild-type form of PfCRT does not. However, little is understood about the transport of other drugs via PfCRT or the mechanism by which PfCRT recognizes different substrates. Here we show that mutant PfCRT also transports quinine, quinidine, and verapamil, indicating that the protein behaves as a multidrug resistance carrier. Detailed kinetic analyses revealed that chloroquine and quinine compete for transport via PfCRT in a manner that is consistent with mixed-type inhibition. Moreover, our analyses suggest that PfCRT accepts chloroquine and quinine at distinct but antagonistically interacting sites. We also found verapamil to be a partial mixed-type inhibitor of chloroquine transport via PfCRT, further supporting the idea that PfCRT possesses multiple substrate-binding sites. Our findings provide new mechanistic insights into the workings of PfCRT, which could be exploited to design potent inhibitors of this key mediator of drug resistance.
From the Department of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
Sebastiano
S
Bellanca
the Research School of Biology, Australian National University, Canberra, Australian Capital Territory 0200, Australia, and.
Robert L
RL
Summers
From the Department of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
Max
M
Meyrath
From the Department of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
Anurag
A
Dave
the Research School of Biology, Australian National University, Canberra, Australian Capital Territory 0200, Australia, and.
Megan N
MN
Nash
From the Department of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
Martin
M
Dittmer
From the Department of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
Cecilia P
CP
Sanchez
the Department of Biological Chemistry, Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Wilfred D
WD
Stein
the Research School of Biology, Australian National University, Canberra, Australian Capital Territory 0200, Australia, and rowena.martin@anu.edu.au.
Rowena E
RE
Martin
From the Department of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany, michael_lanzer@med.uni-heidelberg.de.
Michael
M
Lanzer
D000818:Animals; D000962:Antimalarials / Q000378:metabolism* / Q000494:pharmacology; D001665:Binding Sites; D001667:Binding, Competitive; D001692:Biological Transport; D002478:Cells, Cultured; D002738:Chloroquine / Q000378:metabolism / Q000494:pharmacology; D004351:Drug Resistance; D005260:Female; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D026901:Membrane Transport Proteins / Q000502:physiology*; D010963:Plasmodium falciparum / Q000378:metabolism*; D015800:Protozoan Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D011802:Quinidine / Q000378:metabolism; D011803:Quinine / Q000378:metabolism; D014700:Verapamil / Q000378:metabolism / Q000494:pharmacology; D014982:Xenopus laevis
D000962:Antimalarials; D026901:Membrane Transport Proteins; C416369:PfCRT protein, Plasmodium falciparum; D015800:Protozoan Proteins; D002738:Chloroquine; D011803:Quinine; D014700:Verapamil; D011802:Quinidine
Chloroquine; Drug Resistance; Malaria; Membrane Transport; Mixed-type Inhibition; Parasitology; Quinine; Transporter; Verapamil