A high-affinity putrescine-cadaverine transporter from Trypanosoma cruzi.
Whereas mammalian cells and most other organisms can synthesize polyamines from basic amino acids, the protozoan parasite Trypanosoma cruzi is incapable of polyamine biosynthesis de novo and therefore obligatorily relies upon putrescine acquisition from the host to meet its nutritional requirements. The cell surface proteins that mediate polyamine transport into T. cruzi, as well as most eukaryotes, however, have by-in-large eluded discovery at the molecular level. Here we report the identification and functional characterization of two polyamine transporters, TcPOT1.1 and TcPOT1.2, encoded by alleles from two T. cruzi haplotypes. Overexpression of the TcPOT1.1 and TcPOT1.2 genes in T. cruzi epimastigotes revealed that TcPOT1.1 and TcPOT1.2 were high-affinity transporters that recognized both putrescine and cadaverine but not spermidine or spermine. Furthermore, the activities and subcellular locations of both TcPOT1.1 and TcPOT1.2 in intact parasites were profoundly influenced by extracellular putrescine availability. These results establish TcPOT1.1 and TcPOT1.2 as key components of the T. cruzi polyamine transport pathway, an indispensable nutritional function for the parasite that may be amenable to therapeutic manipulation.
Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR 97239-3098, USA.
Marie-Pierre
MP
Hasne
Isabelle
I
Coppens
Radika
R
Soysa
Buddy
B
Ullman
D002103:Cadaverine / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry; D003593:Cytoplasm / Q000737:chemistry; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism*; D011700:Putrescine / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D013095:Spermidine / Q000378:metabolism; D013096:Spermine / Q000378:metabolism; D013379:Substrate Specificity; D014349:Trypanosoma cruzi / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism
D016054:DNA, Protozoan; D026901:Membrane Transport Proteins; D015800:Protozoan Proteins; D013096:Spermine; D002103:Cadaverine; D013095:Spermidine; D011700:Putrescine