Characterization of D-glucose transport in Trypanosoma rangeli.
Like in other trypanosomatids D-glucose is a crucial source of energy to Trypanosoma rangeli, a non-pathogenic parasite that in Central and South America infects triatomine vectors and different mammalian species, including humans. In several trypanosome species, D-glucose transporters were already described and cloned. In this study, we characterized the D-glucose transport activity present in 2 life-stage forms of T. rangeli (epimastigotes and trypomastigotes) using D-[U-14C]glucose as substrate. Our results indicate that T. rangeli transports D-glucose with high affinity in both epimastigote (Km 30 microM) and trypomastigotes (Km 80 microM) life-forms. Both transport activities were inhibited by Cytochalasin B and Phloretin, indicating that probably D-glucose uptake in T. rangeli is mediated by facilitated diffusion of the sugar. Significant differences were observed between epimastigotes and trypomastigotes in relation to their affinity for D-glucose analogues, and the predicted amino acid sequence of a putative D-glucose transporter from T. rangeli (TrHT1) showed a larger identity with the T. cruzi D-glucose transporter encoded by the TcrHT1 gene than with other transporters already characterized in trypanosomatids.
Miletti
L C
LC
Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC 88040-900, Brazil. lcmilett@yahoo.com.br
Koerich
L B
LB
Pacheco
L K
LK
Steindel
M
M
Stambuk
B U
BU
D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D005947:Glucose / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014345:Trypanosoma / Q000254:growth & development* / Q000378:metabolism*
D009004:Monosaccharide Transport Proteins; D015800:Protozoan Proteins; C100828:TcrHT1 protein, Trypanosoma cruzi; D005947:Glucose