PfNT2, a permease of the equilibrative nucleoside transporter family in the endoplasmic reticulum of Plasmodium falciparum

J Biol Chem. 2010 Jul 2;285(27):20827-33. doi: 10.1074/jbc.M110.118489. Epub 2010 May 3.


The survival and proliferation of the obligate intracellular malaria parasite Plasmodium falciparum require salvage of essential purines from the host. Genetic studies have previously shown that the parasite plasma membrane purine permease, PfNT1, plays an essential function in the transport of all naturally occurring purine nucleosides and nucleobases across the parasite plasma membrane. Here, we describe an intracellular permease, PfNT2. PfNT2 is, like PfNT1, a member of the equilibrative nucleoside transporter family. Confocal and immunoelectron microscopic analyses of transgenic parasites harboring green fluorescent protein- or hemagglutinin-tagged PfNT2 demonstrated endoplasmic reticulum localization. This localization was confirmed by colocalization with the endoplasmic reticulum marker PfBiP. Using yeast as a surrogate system, we show that targeting PfNT2 to the plasma membrane of fui1Delta cells lacking the plasma membrane nucleoside transporter Fui1 confers sensitivity to the toxic nucleoside analog 5-fluorouridine. This study provides the first evidence of an intracellular purine permease in apicomplexan parasites and suggests a novel biological function for the parasite endoplasmic reticulum during malaria infection.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Endoplasmic Reticulum / enzymology*
  • Endoplasmic Reticulum / ultrastructure
  • Erythrocytes / parasitology
  • Floxuridine / metabolism
  • Genes, Reporter
  • Host-Parasite Interactions
  • Humans
  • Malaria, Falciparum / blood
  • Membrane Transport Proteins / genetics*
  • Membrane Transport Proteins / metabolism
  • Microscopy, Immunoelectron
  • Nucleoside Transport Proteins / genetics*
  • Nucleoside Transport Proteins / metabolism
  • Parasitemia / blood
  • Plasmodium falciparum / enzymology*
  • Plasmodium falciparum / genetics
  • Promoter Regions, Genetic
  • Protozoan Proteins / genetics
  • Protozoan Proteins / metabolism
  • Purines / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / growth & development
  • Transfection


  • Membrane Transport Proteins
  • Nucleoside Transport Proteins
  • Protozoan Proteins
  • Purines
  • Floxuridine