The glycosomal-membrane associated phosphoglycerate kinase isoenzyme A plays a role in sustaining the glucose flux in Trypanosoma cruzi epimastigotes.
In Trypanosoma cruzi three isoenzymes of phosphoglycerate kinase (PGK) are found which are simultaneously expressed: the cytosolic isoenzyme PGKB as well as two glycosomal enzymes, PGKA and PGKC. In this paper, we show that PGKA in T. cruzi epimastigotes is associated to the glycosomal membrane; it is responsible for about 23% of the glycosomal PGK activity, the fraction that remains in the pellet after osmotic shock treatment of purified organelles, in contrast to the 77% soluble activity that is mainly attributed to PGKC. Antibodies against the unique 80 amino-acid insertion of PGKA blocked almost completely the glucose consumption by epimastigotes that were partially permeabilized with digitonin. These results indicate that PGKA is the predominant isoenzyme for sustaining glycolysis through the glycosomes of these parasites.
Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de los Andes, La Hechicera, 5101 Mérida, Venezuela.
Ximena
X
Barros-Álvarez
Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de los Andes, La Hechicera, 5101 Mérida, Venezuela.
Ana J
AJ
Cáceres
Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de los Andes, La Hechicera, 5101 Mérida, Venezuela.
Maria T
MT
Ruiz
Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de los Andes, La Hechicera, 5101 Mérida, Venezuela; Research Unit for Tropical Diseases, de Duve Institute, Université catholique de Louvain, Brussels, Belgium.
Paul A M
PA
Michels
Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de los Andes, La Hechicera, 5101 Mérida, Venezuela.
Juan Luis
JL
Concepción
Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de los Andes, La Hechicera, 5101 Mérida, Venezuela. Electronic address: wilqui@ula.ve.
Wilfredo
W
Quiñones
D001692:Biological Transport; D014355:Chagas Disease / Q000469:parasitology; D003600:Cytosol / Q000201:enzymology; D005947:Glucose / Q000378:metabolism*; D006019:Glycolysis; D006801:Humans; D007425:Intracellular Membranes / Q000201:enzymology* / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008830:Microbodies / Q000201:enzymology*; D010735:Phosphoglycerate Kinase / Q000235:genetics / Q000378:metabolism*; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D014349:Trypanosoma cruzi / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
D007527:Isoenzymes; D015800:Protozoan Proteins; D010735:Phosphoglycerate Kinase; D005947:Glucose
Carbohydrate metabolism regulation; Digitonin; Glycolysis; Osmotic shock; Phosphoglycerate kinase; Trypanosoma cruzi