Functional expression and subcellular localization of a high-Km hexose transporter from Leishmania donovani.
We have used expression in Xenopus oocytes to characterize a new hexose transporter from the parasitic protozoan Leishmania donovani. This transporter utilizes the hexoses glucose, fructose, and mannose as substrates. A substrate saturation curve for 2-deoxy-D-glucose reveals a very high Km, estimated to be approximately 150 mM. Immunolocalization of the protein with an antibody directed against the COOH terminus indicates that the transporter is present primarily in the parasite plasma membrane but is not detectable in the flagellar membrane. Since this protein is expressed in the insect stage promastigotes but not in the intracellular amastigotes, it may be specialized to function following an insect sugar meal when the concentrations of sugars surrounding the parasite are high.
Langford
C K
CK
Department of Molecular Microbiology and Immunology, Oregan Health Sciences University, Portland 97201, USA.
Kavanaugh
M P
MP
Stenberg
P E
PE
Drew
M E
ME
Zhang
W
W
Landfear
S M
SM
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002241:Carbohydrates / Q000494:pharmacology; D003847:Deoxyglucose / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D017125:Genes, Protozoan; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007700:Kinetics; D007893:Leishmania donovani / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D016253:Microscopy, Immunoelectron; D009004:Monosaccharide Transport Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009705:Nucleosides / Q000494:pharmacology; D009865:Oocytes / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D014981:Xenopus
D002241:Carbohydrates; D009004:Monosaccharide Transport Proteins; D009705:Nucleosides; D003847:Deoxyglucose