title: Copper pathways in Plasmodium falciparum infected erythrocytes indicate an efflux role for the copper P-ATPase.
abstract: Copper, like iron, is a transition metal that can generate oxygen radicals by the Fenton reaction. The Plasmodium parasite invades an erythrocyte host cell containing 20 microM copper, of which 70% is contained in the Cu/Zn SOD (cuprozinc superoxide dismutase). In the present study, we follow the copper pathways in the Plasmodium-infected erythrocyte. Metal-determination analysis shows that the total copper content of Percoll-purified trophozoite-stage-infected erythrocytes is 66% that of uninfected erythrocytes. This decrease parallels the decrease seen in Cu/Zn SOD levels in parasite-infected erythrocytes. Neocuproine, an intracellular copper chelator, arrests parasites at the ring-to-trophozoite stage transition and also specifically decreases intraparasitic levels of Cu/Zn SOD and catalase. Up to 150 microM BCS (2,9-dimethyl-4,7-diphenyl-1,10-phenanthrolinedisulphonic acid), an extracellular copper chelator, has no effect on parasite growth. We characterized a single copy PfCuP-ATPase (Plasmodium falciparum copper P-ATPase) transporter, which, like the Crypto-sporidium parvum copper P-ATPase, has a single copper-binding domain: 'Met-Xaa-Cys-Xaa-Xaa-Cys'. Recombinant expression of the N-terminal metal-binding domain reveals that the protein specifically binds reduced copper. Transcription of the PfCuP-ATPase gene is the highest at late ring stage/early trophozoite, and is down-regulated in the presence of neocuproine. Immunofluorescence and electron microscopy indicate the transporter to be both in the parasite and on the erythrocyte membrane. Both the decrease in total copper and the location of the PfCuP-ATPase gene indicate a copper-efflux pathway from the infected erythrocyte.
authors.affiliation: The Malaria Research Institute, W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, The Johns Hopkins University, 615 North Wolfe Street, Baltimore, MD 21205, USA.
authors.forename: Dominique
authors.initials: D
authors.lastname: Rasoloson
authors.forename: Lirong
authors.initials: L
authors.lastname: Shi
authors.forename: Curtis R
authors.initials: CR
authors.lastname: Chong
authors.forename: Bjorn F
authors.initials: BF
authors.lastname: Kafsack
authors.forename: David J
authors.initials: DJ
authors.lastname: Sullivan
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000502:physiology*; D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D029681:Arabidopsis Proteins / Q000235:genetics; D029742:Caenorhabditis elegans Proteins / Q000235:genetics; D027682:Cation Transport Proteins / Q000235:genetics / Q000502:physiology*; D002614:Chelating Agents / Q000494:pharmacology; D002874:Chromosome Mapping / Q000379:methods; D003300:Copper / Q000378:metabolism*; D016054:DNA, Protozoan / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics; D004910:Erythrocyte Membrane / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D004912:Erythrocytes / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism* / Q000469:parasitology*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010618:Phenanthrolines / Q000494:pharmacology; D010963:Plasmodium falciparum / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D015800:Protozoan Proteins / Q000737:chemistry / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D020539:Sequence Analysis, Protein / Q000379:methods; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D029742:Caenorhabditis elegans Proteins; D027682:Cation Transport Proteins; D002614:Chelating Agents; D016054:DNA, Protozoan; D029721:Drosophila Proteins; D010618:Phenanthrolines; D015800:Protozoan Proteins; D029701:Saccharomyces cerevisiae Proteins; D003300:Copper; C002701:neocuproine; D013482:Superoxide Dismutase; D000251:Adenosine Triphosphatases