title: Identification and characterization of a polyamine permease from the protozoan parasite Leishmania major.
abstract: The proteins that mediate polyamine translocation into eukaryotic cells have not been identified at the molecular level. To define the polyamine transport pathways in eukaryotic cells we have cloned a gene, LmPOT1, that encodes a polyamine transporter from the protozoan pathogen, Leishmania major. Sequence analysis of LmPOT1 predicted an unusual 803-residue polytopic protein with 9-12 transmembrane domains. Expression of LmPOT1 cRNA in Xenopus laevis oocytes revealed LmPOT1 to be a high affinity transporter for both putrescine and spermidine, whereas expression of LmPOT1 in Trypanosoma brucei stimulated putrescine uptake that was sensitive to inhibition by pentamidine and proton ionophores. Immunoblot analysis established that LmPOT1 was expressed predominantly in the insect vector form of L. major, and immunofluorescence demonstrated that LmPOT1 was localized predominantly to the parasite plasma membrane. To our knowledge this is the first molecular identification and characterization of a cell surface polyamine transporter in eukaryotic cells.
authors.affiliation: Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239-3098, USA.
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Hasne
authors.forename: Buddy
authors.initials: B
authors.lastname: Ullman
mesh_terms: D000465:Algorithms; D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D015153:Blotting, Western; D027682:Cation Transport Proteins / Q000737:chemistry* / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D004305:Dose-Response Relationship, Drug; D015151:Immunoblotting; D007150:Immunohistochemistry; D018320:Leishmania major; D008024:Ligands; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D010419:Pentamidine / Q000494:pharmacology; D011073:Polyamines / Q000737:chemistry / Q000378:metabolism; D011522:Protons; D011700:Putrescine / Q000737:chemistry; D018075:RNA, Complementary / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012964:Sodium / Q000737:chemistry / Q000378:metabolism; D013095:Spermidine / Q000737:chemistry; D014162:Transfection; D014982:Xenopus laevis
chemical_list: D027682:Cation Transport Proteins; D008024:Ligands; D026901:Membrane Transport Proteins; C500804:POT1 protein, Leishmania major; D011073:Polyamines; D011522:Protons; D018075:RNA, Complementary; D010419:Pentamidine; D012964:Sodium; D013095:Spermidine; D011700:Putrescine