The objective of this proposal is to characterize at the molecular level several transporters from Leishmania and trypanosomes that mediate the uptake of important nutrients from the hosts. These nutrients include glucose which is an major source of metabolic energy in the insect stage of the life cycle, purines which are essential nutrients that the parasites cannot synthesize de novo, and amino acids which are both catabolized to generate energy and utilized in anabolic pathways such as protein synthesis. In the first aim, the physiological functions of the LdGT1 and LdGT2 glucose transporter isoforms of L. donovani will be probed by generating null mutants and analyzing their phenotypes. These studies may elucidate the functional differences between the flagellar membrane LdGT1 and the pellicular plasma membrane LdGT2. In the second aim, the permeation pathway of the L. donovani adenosine/pyrimidine nucleoside transporter LdNT1.1 will be probed by a combination of cysteine-scanning mutagenesis and sulfhydryl group chemical modification. These studies have been guided by the detection of two distinct point mutations that inactivate LdNT1.1, possibly by altering amino acids that line the permeation pathway. The TbNT8 transporter from Trypanosoma brucei, whose mRNA is expressed exclusively in insect stage parasites, is closely related in sequence to other well characterized nucleoside transporters, but it's function remains to be defined.
This third aim will characterize a strongly developmentally regulated nucleoside transporter and allow its comparison to other bloodstream-specific nucleoside transporters.
The final aim will functionally characterize a novel amino acid transporter from L. major that is related in sequence to mamrnalian N-type amino acid permeases that mediate the uptake of glutamine, and histidine, essential amino acids for growth of Leishmania parasites. These studies will initiate the molecular analysis of amino acid transporters in Leishmania.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI025920-18
Application #
6896092
Study Section
Special Emphasis Panel (ZRG1-VR (01))
Program Officer
Rogers, Martin J
Project Start
1991-09-01
Project End
2006-05-31
Budget Start
2005-06-01
Budget End
2006-05-31
Support Year
18
Fiscal Year
2005
Total Cost
$339,750
Indirect Cost
Name
Oregon Health and Science University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
096997515
City
Portland
State
OR
Country
United States
Zip Code
97239
Landfear, Scott M; Tran, Khoa D; Sanchez, Marco A (2015) Flagellar membrane proteins in kinetoplastid parasites. IUBMB Life 67:668-76
Rodriguez-Contreras, Dayana; Aslan, Hamide; Feng, Xiuhong et al. (2015) Regulation and biological function of a flagellar glucose transporter in Leishmania mexicana: a potential glucose sensor. FASEB J 29:11-24
Rodriguez-Contreras, Dayana; Landfear, Scott M (2014) Transporters, channels and receptors in flagella. Channels (Austin) 8:477-8
Tran, Khoa D; Rodriguez-Contreras, Dayana; Vieira, Danielle P et al. (2013) KHARON1 mediates flagellar targeting of a glucose transporter in Leishmania mexicana and is critical for viability of infectious intracellular amastigotes. J Biol Chem 288:22721-33
Feng, Xiuhong; Rodriguez-Contreras, Dayana; Polley, Tamsen et al. (2013) 'Transient' genetic suppression facilitates generation of hexose transporter null mutants in Leishmania mexicana. Mol Microbiol 87:412-29
Tran, Khoa D; Rodriguez-Contreras, Dayana; Shinde, Ujwal et al. (2012) Both sequence and context are important for flagellar targeting of a glucose transporter. J Cell Sci 125:3293-8
Blume, Martin; Hliscs, Marion; Rodriguez-Contreras, Dayana et al. (2011) A constitutive pan-hexose permease for the Plasmodium life cycle and transgenic models for screening of antimalarial sugar analogs. FASEB J 25:1218-29
Vince, James E; Tull, Dedreia; Landfear, Scott et al. (2011) Lysosomal degradation of Leishmania hexose and inositol transporters is regulated in a stage-, nutrient- and ubiquitin-dependent manner. Int J Parasitol 41:791-800
Feng, Xiuhong; Feistel, Torben; Buffalo, Cosmo et al. (2011) Remodeling of protein and mRNA expression in Leishmania mexicana induced by deletion of glucose transporter genes. Mol Biochem Parasitol 175:39-48
Landfear, S M (2010) Transporters for drug delivery and as drug targets in parasitic protozoa. Clin Pharmacol Ther 87:122-5

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