title: The Mu subunit of Plasmodium falciparum clathrin-associated adaptor protein 2 modulates in vitro parasite response to artemisinin and quinine.
abstract: The emergence of drug-resistant parasites is a serious threat faced by malaria control programs. Understanding the genetic basis of resistance is critical to the success of treatment and intervention strategies. A novel locus associated with antimalarial resistance, ap2-mu (encoding the mu chain of the adaptor protein 2 [AP2] complex), was recently identified in studies on the rodent malaria parasite Plasmodium chabaudi (pcap2-mu). Furthermore, analysis in Kenyan malaria patients of polymorphisms in the Plasmodium falciparum ap2-mu homologue, pfap2-mu, found evidence that differences in the amino acid encoded by codon 160 are associated with enhanced parasite survival in vivo following combination treatments which included artemisinin derivatives. Here, we characterize the role of pfap2-mu in mediating the in vitro antimalarial drug response of P. falciparum by generating transgenic parasites constitutively expressing codon 160 encoding either the wild-type Ser (Ser160) or the Asn mutant (160Asn) form of pfap2-mu. Transgenic parasites carrying the pfap2-mu 160Asn allele were significantly less sensitive to dihydroartemisinin using a standard 48-h in vitro test, providing direct evidence of an altered parasite response to artemisinin. Our data also provide evidence that pfap2-mu variants can modulate parasite sensitivity to quinine. No evidence was found that pfap2-mu variants contribute to the slow-clearance phenotype exhibited by P. falciparum in Cambodian patients treated with artesunate monotherapy. These findings provide compelling evidence that pfap2-mu can modulate P. falciparum responses to multiple drugs. We propose that this gene should be evaluated further as a potential molecular marker of antimalarial resistance.
authors.affiliation: Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Gisela
authors.initials: G
authors.lastname: Henriques
authors.affiliation: Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Donelly A
authors.initials: DA
authors.lastname: van Schalkwyk
authors.affiliation: Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Rebekah
authors.initials: R
authors.lastname: Burrow
authors.affiliation: Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: David C
authors.initials: DC
authors.lastname: Warhurst
authors.affiliation: Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Eloise
authors.initials: E
authors.lastname: Thompson
authors.affiliation: Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: David A
authors.initials: DA
authors.lastname: Baker
authors.affiliation: Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, New York, USA Division of Infectious Diseases, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Fidock
authors.affiliation: Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Rachel
authors.initials: R
authors.lastname: Hallett
authors.affiliation: Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Christian
authors.initials: C
authors.lastname: Flueck
authors.affiliation: Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom Department of Clinical Parasitology, Hospital for Tropical Diseases, University College London Hospital, London, United Kingdom Colin.sutherland@lshtm.ac.uk.
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Sutherland
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D037621:Artemisinins / Q000494:pharmacology*; D018076:DNA, Complementary; D016366:Open Reading Frames / Q000235:genetics; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011803:Quinine / Q000494:pharmacology*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D037621:Artemisinins; D018076:DNA, Complementary; D021122:Protein Subunits; C031327:artemisinin; D011803:Quinine