Secretion by Trypanosoma cruzi of a hemolysin active at low pH

Andrews, Norma W.; Whitlow, Michael B.

doi:10.1016/0166-6851(89)90086-8

Cited by 88 publications

(61 citation statements)

References 18 publications

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“…2) but dramatically affected their escape, increasing the mean residence by at least a factor of two, whereas not affecting the parameters of amastigote transit, suggesting that the mechanisms engaged for parasitophorous membrane disruption is stage-specific. Of the two known components involved, hemolysin and transialidase, (Andrews & Whitlow 1989, Hall et al 1992) only hemolysin activity could be detected in amastigotes whereas in metacyclic trypomastigotes none of the activities could be detected. a: T 1/2 formation: half-life for parasitophorous vacuole formation.…”

Section: Discussionmentioning

confidence: 92%

“…Hemolysin and transialidase assays -Hemolysin (TcTOX) activity was determined as described by Andrews and Whitlow (1989), with minor modifications. Briefly, freshly collected female albino mouse erythrocytes were washed three times with isotonic PBS/ 0.1% gelatin, 0.15% CaCl 2 and 1mM MgCl 2 .…”

Section: Methodsmentioning

confidence: 99%

“…It has been shown that Ca 2+ mobilization is involved in the signaling pathway leading to parasitophorous vacuole formation during trypomastigote invasion (Burleigh & Andrews 1995). Moreover, the combined activities of hemolysin and transialidase, activated within the acidified trypomastigote parasitophorous vacuole, are believed to be crucial in providing the means for these forms to escape into the cytoplasm, that is facilitated in cells lacking proper sialylation of lysosomal glycoproteins (Andrews & Whitlow 1989, Hall et al 1992. By contrast, little is known on the signals triggered during amastigote invasion, and the available data (Procópio et al 1998) indicate that parasitophorous vacuole formation probably involves lysosomal recruitment.…”

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confidence: 99%

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Parameters affecting cellular invasion and escape from the parasitophorous vacuole by different infective forms of Trypanosoma cruzi

Stecconi-Silva

Andreoli

Mortara

2003

Mem. Inst. Oswaldo Cruz

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Section: Discussionmentioning

confidence: 92%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Parameters affecting cellular invasion and escape from the parasitophorous vacuole by different infective forms of Trypanosoma cruzi

Stecconi-Silva

Andreoli

Mortara

2003

Mem. Inst. Oswaldo Cruz

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“…9A). Although lytic activity has been primarily associated with amastigotes, epimastigotes have also been shown to express low levels of lytic activity (1). Consequently, the lytic activity of wild-type and LYT1 mutant parasites was assessed, with the result that in each case mutant epimastigotes expressed less lytic activity than wild-type epimastigotes did (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…One parasite factor likely to be involved is TC-TOX, a secreted acidstable hemolytic protein (2). This protein has membrane poreforming activity at low pH levels and cross-reacts with monoclonal antibodies directed against C9, and it has been postulated that it mediates the escape of T. cruzi from the parasitophorous vacuole into the cytosol (1,5). Another protein shown to be involved in infection was a trypomastigotesecreted peptidyl-prolyl cis or trans isomerase (17), but its specific target on the host cell remains to be elucidated.…”

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LYT1 Protein Is Required for Efficient In Vitro Infection by Trypanosoma cruzi

et al. 2001

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Trypanosoma cruzi invasion of host cells involves several discrete steps: attachment, parasite internalization mediated by recruitment and fusion of host cell lysosomes, and escape from the parasitophorous vacuole to liberate amastigotes to multiply freely in the cytosol. This report describes the initial characterization of the LYT1 gene and the demonstration that the gene product is involved in cell lysis and infectivity. Mutational analysis demonstrated that deletion of LYT1 resulted in attenuation of infection, which was associated with diminished hemolytic activity. Reintroduction of LYT1 restored infectivity in null mutants, confirming the critical role of LYT1 in infection. Additionally, in vitro stage transition experiments with LYT1-deficient lines showed that these parasites converted to extracellular amastigote-like cells and metacyclic trypomastigotes more rapidly than wild-type parasites, suggesting that the diminished infectivity was not a result of the LYT1 deficiency that affected the parasite's ability to complete the life cycle.

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Secretion by Trypanosoma cruzi of a peptidyl-prolyl cis-trans isomerase involved in cell infection.

et al. 1995

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Macrophage infectivity potentiators are membrane proteins described as virulence factors in bacterial intracellular parasites, such as Legionella and Chlamydia. These factors share amino acid homology to eukaryotic peptidyl-prolyl cis-trans isomerases that are inhibited by FK506, an inhibitor of signal transduction in mammalian cells with potent immunosuppressor activity. We report here the characterization of a protein released into the culture medium by the infective stage of the protozoan intracellular parasite Trypanosoma cruzi. The protein possesses a peptidylprolyl cis-trans isomerase activity that is inhibited by FK506 and its non-immunosuppressing derivative L-685,818. The corresponding gene presents sequence homology with bacterial macrophage infectivity potentiators. The addition of the protein, produced heterologously in Escherichia coli, to cultures of trypomastigotes and simian epithelial or HeLa cells enhances invasion of the mammalian cells by the parasites. Antibodies raised in mice against the T.cruzi isomerase greatly reduce infectivity. A similar reduction of infectivity is obtained by addition to the cultures of FK506 and L-685,818. We concluded that the T.cruzi isomerase is involved in cell invasion.

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Secretion by Trypanosoma cruzi of a hemolysin active at low pH

Cited by 88 publications

References 18 publications

Parameters affecting cellular invasion and escape from the parasitophorous vacuole by different infective forms of Trypanosoma cruzi

Parameters affecting cellular invasion and escape from the parasitophorous vacuole by different infective forms of Trypanosoma cruzi

LYT1 Protein Is Required for Efficient In Vitro Infection by Trypanosoma cruzi

Secretion by Trypanosoma cruzi of a peptidyl-prolyl cis-trans isomerase involved in cell infection.

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