Molecular and functional characterization and tissue localization of 2 glucose transporter homologues (TGTP1 and TGTP2) from the tapeworm Taenia solium.
Tapeworms absorb and consume large quantities of glucose through their syncytial tegument, storing the excess as glycogen. Although some studies on the metabolism of glucose in several tapeworms are available, the proteins that mediate its uptake and distribution in their tissue have not been identified. We describe the isolation and characterization of cDNA clones encoding 2 facilitated diffusion glucose transporters (TGTP1 and TGTP2) from Taenia solium, the causal agent of human and porcine cysticercosis. Radio-isotope labelled hexose uptake mediated by TGTP1 expressed in Xenopus oocytes is inhibited by the natural stereoisomers D-glucose and D-mannose but not by L-glucose. Transport by TGTP1 is sensitive to classical inhibitors of facilitated diffusion such as phloretin and cytochalasin B, and insensitive to ouabain. TGTP2 did not function in Xenopus oocytes. Localization studies using specific anti-TGTP1 and anti-TGTP2 antibodies show that TGTP1 is abundant in a number of structures underlying the tegument in adult parasites and larvae, whereas TGTP2 appears to be localized only on the tegumentary surface of the larvae and is not detected in adults.
Rodríguez-Contreras
D
D
Department of Immunology, Facultad de Medicina, Universidad Nacional Autónoma de México, México D.F.
Skelly
P J
PJ
Landa
A
A
Shoemaker
C B
CB
Laclette
J P
JP
D000595:Amino Acid Sequence; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D000918:Antibody Specificity; D016367:Baculoviridae / Q000235:genetics; D006224:Cricetinae; D018076:DNA, Complementary / Q000235:genetics; D019084:Fluorescent Antibody Technique, Indirect; D005822:Genetic Vectors; D005947:Glucose / Q000378:metabolism; D051246:Glucose Transport Proteins, Facilitative; D015801:Helminth Proteins / Q000737:chemistry / Q000378:metabolism*; D008358:Mannose / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009865:Oocytes / Q000737:chemistry; D016133:Polymerase Chain Reaction; D013552:Swine; D013621:Taenia / Q000737:chemistry* / Q000254:growth & development
D000909:Antibodies, Helminth; D018076:DNA, Complementary; D051246:Glucose Transport Proteins, Facilitative; D015801:Helminth Proteins; D009004:Monosaccharide Transport Proteins; C117622:TGTP1 protein, Taenia solium; C117623:TGTP2 protein, Taenia solium; D005947:Glucose; D008358:Mannose