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Blood, 1 March 2007, Vol. 109, No. 5, pp. 2217-2224. Prepublished online as a Blood First Edition Paper on October 17, 2006; DOI 10.1182/blood-2005-11-026963. This Article Full Text Full Text (PDF) All Versions of this Article: blood-2005-11-026963v1 109/5/2217    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Martin, R. E. Articles by Kirk, K. Search for Related Content PubMed PubMed Citation Articles by Martin, R. E. Articles by Kirk, K. Related Collections Red Cells Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  RED CELLS Transport of the essential nutrient isoleucine in human erythrocytes infected with the malaria parasite Plasmodium falciparum Rowena E. Martin1, and Kiaran Kirk1 1 School of Biochemistry and Molecular Biology, The Australian National University, Canberra, Australia The intraerythrocytic malaria parasite derives much of its requirement for amino acids from the digestion of the hemoglobin of its host cell. However, one amino acid, isoleucine, is absent from adult human hemoglobin and must therefore be obtained from the extracellular medium. In this study we have characterized the mechanisms involved in the uptake of isoleucine by the intraerythrocytic parasite. Under physiologic conditions the rate of transport of isoleucine into human erythrocytes infected with mature trophozoite-stage Plasmodium falciparum parasites is increased to approximately 5-fold that in uninfected cells, with the increased flux being via the new permeability pathways (NPPs) induced by the parasite in the host cell membrane. Transport via the NPPs ensures that protein synthesis is not rate limited by the flux of isoleucine across the erythrocyte membrane. On entering the infected erythrocyte, isoleucine is taken up into the parasite via a saturable, ATP-, Na+-, and H+-independent system which has the capacity to mediate the influx of isoleucine in exchange for leucine (liberated from hemoglobin). The accumulation of radiolabeled isoleucine within the parasite is mediated by a second (high-affinity, ATP-dependent) mechanism, perhaps involving metabolism and/or the concentration of isoleucine within an intracellular organelle. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: A. M. Lehane, R. Hayward, K. J. Saliba, and K. Kirk A verapamil-sensitive chloroquine-associated H+ leak from the digestive vacuole in chloroquine-resistant malaria parasites J. Cell Sci., May 15, 2008; 121(10): 1624 - 1632. [Abstract] [Full Text] [PDF] S. Dalal and M. Klemba Roles for Two Aminopeptidases in Vacuolar Hemoglobin Catabolism in Plasmodium falciparum J. Biol. Chem., December 7, 2007; 282(49): 35978 - 35987. [Abstract] [Full Text] [PDF]

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