title: Genetic linkage of pfmdr1 with food vacuolar solute import in Plasmodium falciparum.
abstract: The P-glycoprotein homolog of the human malaria parasite Plasmodium falciparum (Pgh-1) has been implicated in decreased susceptibility to several antimalarial drugs, including quinine, mefloquine and artemisinin. Pgh-1 mainly resides within the parasite's food vacuolar membrane. Here, we describe a surrogate assay for Pgh-1 function based on the subcellular distribution of Fluo-4 acetoxymethylester and its free fluorochrome. We identified two distinct Fluo-4 staining phenotypes: preferential staining of the food vacuole versus a more diffuse staining of the entire parasite. Genetic, positional cloning and pharmacological data causatively link the food vacuolar Fluo-4 phenotype to those Pgh-1 variants that are associated with altered drug responses. On the basis of our data, we propose that Pgh-1 imports solutes, including certain antimalarial drugs, into the parasite's food vacuole. The implications of our findings for drug resistance mechanisms and testing are discussed.
authors.affiliation: Hygiene Institut, Abteilung Parasitologie, Universitätsklinikum Heidelberg, Heidelberg, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Rohrbach
authors.forename: Cecilia P
authors.initials: CP
authors.lastname: Sanchez
authors.forename: Karen
authors.initials: K
authors.lastname: Hayton
authors.forename: Oliver
authors.initials: O
authors.lastname: Friedrich
authors.forename: Jigar
authors.initials: J
authors.lastname: Patel
authors.forename: Amar Bir Singh
authors.initials: AB
authors.lastname: Sidhu
authors.forename: Michael T
authors.initials: MT
authors.lastname: Ferdig
authors.forename: David A
authors.initials: DA
authors.lastname: Fidock
authors.forename: Michael
authors.initials: M
authors.lastname: Lanzer
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000502:physiology*; D000814:Aniline Compounds / Q000737:chemistry*; D000818:Animals; D000962:Antimalarials / Q000378:metabolism / Q000494:pharmacology; D037621:Artemisinins / Q000378:metabolism / Q000494:pharmacology; D001693:Biological Transport, Active; D002463:Cell Membrane Permeability; D002738:Chloroquine / Q000378:metabolism / Q000494:pharmacology; D004351:Drug Resistance; D004912:Erythrocytes / Q000469:parasitology; D005456:Fluorescent Dyes / Q000737:chemistry*; D008040:Genetic Linkage; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000502:physiology*; D007783:Lactones / Q000378:metabolism / Q000494:pharmacology; D010963:Plasmodium falciparum / Q000502:physiology*; D011110:Polymorphism, Genetic; D015800:Protozoan Proteins / Q000235:genetics / Q000502:physiology*; D011803:Quinine / Q000378:metabolism / Q000494:pharmacology; D012717:Sesquiterpenes / Q000378:metabolism / Q000494:pharmacology; D013379:Substrate Specificity; D014617:Vacuoles / Q000502:physiology*; D014966:Xanthenes / Q000737:chemistry*
chemical_list: D018528:ATP-Binding Cassette Transporters; D000814:Aniline Compounds; D000962:Antimalarials; D037621:Artemisinins; C409648:Fluo 4; D005456:Fluorescent Dyes; D007783:Lactones; D015800:Protozoan Proteins; D012717:Sesquiterpenes; D014966:Xanthenes; C059987:mdr gene protein, Plasmodium; D002738:Chloroquine; D011803:Quinine; C075875:artemisin