Ana Paula C. A. Lima

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Lysosomal cysteine proteases from mammalian cells and plants are regulated by endogenous tight-binding inhibitors from the cystatin superfamily. The presence of cystatin-like inhibitors in lower eukaryotes such as protozoan parasites has not yet been demonstrated, although these cells express large quantities of cysteine proteases and may also count on(More)
Cysteine-proteinases from parasitic protozoa have been recently characterized as factors of virulence and pathogenicity in several human and veterinary diseases. In Chagas' disease, the chronic infection caused by Trypanosoma cruzi, structure-functional studies on cysteine proteases were thus far limited to the parasite's major isoform, a cathepsin L-like(More)
Human infection with Trypanosoma cruzi (Chagas' disease) is usually accompanied by humoral and cellular immune responses to GP57/51, a major antigen that was recently identified as a prominent cysteinyl proteinase (cruzipain). The PBMC responses of 11 chronic chagasic patients and the properties of anti-cruzipain T cell lines are reported herein. GP57/51,(More)
The Trypanosoma cruzi cysteine protease cruzipain contains a 130-amino-acid C-terminal extension, in addition to the catalytic domain. Natural cruzipain is a complex of isoforms, because of the simultaneous expression of several genes, and the presence of either high mannose-type, hybrid monoantennary-type or complex biantenary-type oligosacharide chains at(More)
Trypanosoma cruzi relies on highly galactosylated molecules as virulence factors and the enzymes involved in sugar biosynthesis are potential therapeutic targets. The synthesis of UDP-galactose in T. cruzi requires the activity of phosphoglucomutase (PGM), the enzyme that catalyzes the interconversion of glucose-6-phosphate and glucose-1-phosphate. Several(More)
The major isoform of Trypanosoma cruzi cysteinyl proteinase (cruzipain) has generated Lys-bradykinin (Lys-BK or kallidin), a proinflammatory peptide, by proteolysis of kininogen. The releasing of this peptide was demonstrated by mass spectrometry, radioimmunoassay, and ileum contractile responses. The kinin-releasing activity was immunoabsorbed selectively(More)
This study examined the process of membrane fusion of yolk granules (YGs) during early embryogenesis of Rhodnius prolixus. We show that eggs collected at days 0 and 3 after oviposition contain different populations of YGs, for example day-3 eggs are enriched in large YGs (LYGs). Day-3 eggs also contain the highest free [Ca(2+)] during early embryogenesis of(More)
Trypanosomatids rely on peptidases as potent virulence factors and were recently found to contain a unique set of natural peptidase inhibitors not found in higher eukaryotes or in yeast, but present in a limited number of bacteria. Chagasin, identified in Trypanosoma cruzi, is a tight-binding, high affinity inhibitor of papain-like cysteine peptidases that(More)
Glycosylated mouse cystatin C (mCysC), an endogenous inhibitor of cysteine cathepsin proteases (CP), has been suggested as a cofactor of β-FGF to induce the differentiation of mouse embryonic stem cells into neural progenitor cells (NPCs). To investigate the possible role of CP in neural differentiation, we treated embryoid bodies (EBs) with (i) E64, an(More)