Lysine transporters in human trypanosomatid pathogens
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In previous studies we characterized arginine transporter genes from Trypanosoma cruzi and Leishmania donovani, the etiological agents of chagas disease and kala azar, respectively, both fatal diseases in humans. Unlike arginine transporters in higher eukaryotes that transport also lysine, these parasite transporters translocate only arginine. This phenomenon prompted us to identify and characterize parasite lysine transporters. Here we demonstrate that LdAAP7 and TcAAP7 encode lysine-specific permeases in L. donovani and T. cruzi, respectively. These two lysine permeases are both members of the large amino acid/auxin permease family and share certain biochemical properties, such as specificity and Km. However, we evidence that LdAAP7 and TcAAP7 differ in their regulation and localization, such differences are likely a reflection of the dissimilar L. donovani and T. cruzi life cycles. Failed attempts to delete both alleles of LdAAP7 support the premise that this is an essential gene that encodes the only lysine permeases expressed in L. donovani promastigotes and T. cruzi epimastigotes, respectively.
KeywordsLysine transport Amino acid transport Leishmania Trypanosoma
We thank Professor Isabel Roditi for knockout constructs and Ronit Zilberstein-Levy for editing this manuscript. This work was supported by grant number 402/08 from The Israel Science Foundation founded by The Academy of Sciences and Humanities and by grant number CRSII3 127300 from the Swiss National Science Foundation by grants from Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET, PIP 2010 0685) and Agencia Nacional de Promoción Científica y Tecnológica (FONCyT PICT 2005 33431 and PICT 2008 1209). C.A.P. and C.C. are members of the career of scientific investigator of CONICET (Argentina), and G.E.C. is research fellow from CONICET. The study is dedicated to my dear friend Professor Mariano Levin.
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