The expression and intracellular distribution of phosphoglycerate kinase isoenzymes in Trypanosoma cruzi

In this paper, we report the subcellular distribution of phosphoglycerate kinase (PGK) in epimastigotes of Trypanosoma cruzi. Approximately 80% of the PGK activity was found in the cytosol, 20% in the glycosomes. Western blot analysis suggested that two isoenzymes of 56 and 48 kDa, respectively, are...

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Bibliographic Details
Published in:Molecular and biochemical parasitology 2001-11, Vol.118 (1), p.111-121
Main Authors: Concepción, Juan Luis, Adjé, Christiane A., Quiñones, Wilfredo, Chevalier, Nathalie, Dubourdieu, Michel, Michels, Paul A.M.
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Animals
Cytosol - enzymology
Glycosomes
Isoenzymes
Isoenzymes - metabolism
Membrane attachment
Microbodies - enzymology
Molecular Sequence Data
Phosphoglycerate kinase
Phosphoglycerate Kinase - genetics
Phosphoglycerate Kinase - metabolism
Sequence Analysis, DNA
Subcellular Fractions - enzymology
Trypanosoma cruzi
Trypanosoma cruzi - enzymology
Trypanosoma cruzi - genetics
Trypanosoma cruzi - growth & development
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Summary:In this paper, we report the subcellular distribution of phosphoglycerate kinase (PGK) in epimastigotes of Trypanosoma cruzi. Approximately 80% of the PGK activity was found in the cytosol, 20% in the glycosomes. Western blot analysis suggested that two isoenzymes of 56 and 48 kDa, respectively, are responsible for the glycosomal PGK activity, whereas the cytosolic activity should be attributed to a single PGK of 48 kDa. In analogy to the situation previously reported for PGK in Trypanosoma brucei, these isoenzymes were called PGKA, C and B, respectively. However, in T. cruzi, PGKA seems not to be a minor enzyme like its counterpart in T. brucei. Whereas PGKC behaved as a soluble glycosomal matrix protein, PGKA appeared to be present at the inner surface of the organelle's membrane. After alkaline carbonate treatment, the enzyme remained associated with the particulate fraction of the organelles. Upon solubilization of glycosomes with Triton X-114, PGKA was recovered from the detergent phase, indicating its (partial) hydrophobic character and therefore, a possible hydrophobic interaction with the membrane. The PGKA gene was cloned and sequenced, but the predicted amino-acid sequence did not reveal an obvious clue as to the mechanism by which the enzyme is attached to the glycosomal membrane.
ISSN:0166-6851
1872-9428
DOI:10.1016/S0166-6851(01)00381-4