The role of conserved residues of chagasin in the inhibition of cysteine peptidases

Reis, Flavia C G; Smith, Brian O.; Santos, C.; Costa, Tatiana F. R.; Scharfstein, Júlio; Coombs, Graham H.; Mottram, Jeremy C.; Lima, Ana Paula

doi:10.1016/j.febslet.2008.01.008

Cited by 19 publications

(15 citation statements)

References 16 publications

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“…The antimyosin reaction in response to immunization with T. cruzi proteins does not induce cardiac damage (231). Also, the T. cruzi antigens Cha, cruzipain (119), and 45-kDa calreticulin, highly conserved in humans, rabbits, and mice, have been reported to cross-react with host antigens. The challenge of mice with immunogenic recombinant calreticulin induces an inflammatory reaction against a host 45-kDa protein.…”

Section: Autoimmunitymentioning

confidence: 99%

“…However, the clinical and pathological manifestations of the disease have not been obtained by conventional immunizations with wild or with recombinant T. cruzi antigens (386), and therefore, the origin of the autoimmunity in Chagas' disease is unresolved. This explains the necessity to reproduce experimentally the clinical and pathological gross lesions and the microscopic rejection of the target cells in in vivo myocarditis in a parasite-free model system, which cannot be obtained by the injection of antigens into laboratory animals (40,119,152,311,324,344,400,401,417). Within this context, the challenge is to demonstrate that LkDT and VkDT are triggers of the genetically driven autoimmune inflammatory cardiomyopathy in human Chagas' disease.…”

Section: Mosaic Recombination and Hitchhiking: Changing Paradigmmentioning

confidence: 99%

“…The long-standing adaptation of T. cruzi to vertebrate hosts has been credited to the structural and functional polymorphism of cysteine protease isoforms of the parasite cruzipain genes showing different substrate preferences and susceptibility inhibitors (119,237). The generation of kinins by cruzipain results in bradykinin receptor (B 2 R)-mediated signaling through phospholipase C (PLC) and inositol triphosphate (IP 3 )-kinase to release endoplasmic reticulum (ER)-bound calcium (128).…”

Section: Interactions Of Trypanosoma Cruzi With Vertebrate Hostsmentioning

confidence: 99%

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Pathogenesis of Chagas' Disease: Parasite Persistence and Autoimmunity

et al. 2011

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SUMMARY Acute Trypanosoma cruzi infections can be asymptomatic, but chronically infected individuals can die of Chagas' disease. The transfer of the parasite mitochondrial kinetoplast DNA (kDNA) minicircle to the genome of chagasic patients can explain the pathogenesis of the disease; in cases of Chagas' disease with evident cardiomyopathy, the kDNA minicircles integrate mainly into retrotransposons at several chromosomes, but the minicircles are also detected in coding regions of genes that regulate cell growth, differentiation, and immune responses. An accurate evaluation of the role played by the genotype alterations in the autoimmune rejection of self-tissues in Chagas' disease is achieved with the cross-kingdom chicken model system, which is refractory to T. cruzi infections. The inoculation of T. cruzi into embryonated eggs prior to incubation generates parasite-free chicks, which retain the kDNA minicircle sequence mainly in the macrochromosome coding genes. Crossbreeding transfers the kDNA mutations to the chicken progeny. The kDNA-mutated chickens develop severe cardiomyopathy in adult life and die of heart failure. The phenotyping of the lesions revealed that cytotoxic CD45, CD8 + γδ, and CD8α + T lymphocytes carry out the rejection of the chicken heart. These results suggest that the inflammatory cardiomyopathy of Chagas' disease is a genetically driven autoimmune disease.

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Section: Autoimmunitymentioning

confidence: 99%

Section: Mosaic Recombination and Hitchhiking: Changing Paradigmmentioning

confidence: 99%

Section: Interactions Of Trypanosoma Cruzi With Vertebrate Hostsmentioning

confidence: 99%

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Pathogenesis of Chagas' Disease: Parasite Persistence and Autoimmunity

et al. 2011

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“…The first motif of cruzipain has been shown to interact with the catalytic cysteine of the target protease [21]. This was confirmed in a recent mutagenesis study of chagasin in which the L2 loop, containing the NPPTGY motif, was critical to inhibit its native target, cruzain [45]. The key inhibitory residues may depend on the target enzyme, however, as mutants in Loop 4 were critical for leishmanal ICP interactions with papain [46], while the chagasin L6 loop with LxYxRPW was important to inhibit human cathepsin L [45].…”

Section: Discussionmentioning

confidence: 93%

The cathepsin L of Toxoplasma gondii (TgCPL) and its endogenous macromolecular inhibitor, toxostatin

Huang

Que

Hirata

et al. 2009

Molecular and Biochemical Parasitology

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T. gondii is an obligate intracellular parasite of all vertebrates, including man. Successful invasion and replication requires the synchronized release of parasite proteins, many of which require proteolytic processing. Unlike most parasites, T. gondii has a limited number of Clan CA, family C1 cysteine proteinases with one cathepsin B (TgCPB), one cathepsin L (TgCPL) and three cathepsin Cs (TgCPC1, 2, 3). Previously, we characterized toxopain, the only cathepsin B enzyme, which localizes to the rhoptry organelle. Two cathepsin Cs are trafficked through dense granules to the parasitophorous vacuole where they degrade peptides. We now report the cloning, expression, and modeling of the sole cathepsin L gene and the identification of two new endogenous inhibitors. TgCPL differs from human cathepsin L with a pH optimum of 6.5 and its substrate preference for leucine (vs. phenylalanine) in the P2 position. This distinct preference is explained by homology modeling, which reveals a non-canonical aspartic acid (Asp 216) at the base of the predicted active site S2 pocket, which limits substrate access. To further our understanding of the regulation of cathepsins in T. gondii, we identified two genes encoding endogenous cysteine proteinase inhibitors (ICPs or toxostatins), which are active against both TgCPB and TgCPL in the nanomolar range. Over expression of toxostatin-1 significantly decreased overall cysteine proteinase activity in parasite lysates, but had no detectable effect on invasion or intracellular multiplication. These findings provide important insights into the proteolytic cascades of T. gondii and their endogenous control.

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“…These mutations were previously shown not to affect the chagasin structure but significantly reduce the affinity of chagasin for papain [37]. The wild-type and mutant Cip1 proteins are soluble proteins and were purified using the N-terminal His-tag ( Fig 7C ).…”

Section: Resultsmentioning

confidence: 99%

Screen of Non-annotated Small Secreted Proteins of Pseudomonas syringae Reveals a Virulence Factor That Inhibits Tomato Immune Proteases

et al. 2016

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Pseudomonas syringae pv. tomato DC3000 (PtoDC3000) is an extracellular model plant pathogen, yet its potential to produce secreted effectors that manipulate the apoplast has been under investigated. Here we identified 131 candidate small, secreted, non-annotated proteins from the PtoDC3000 genome, most of which are common to Pseudomonas species and potentially expressed during apoplastic colonization. We produced 43 of these proteins through a custom-made gateway-compatible expression system for extracellular bacterial proteins, and screened them for their ability to inhibit the secreted immune protease C14 of tomato using competitive activity-based protein profiling. This screen revealed C14-inhibiting protein-1 (Cip1), which contains motifs of the chagasin-like protease inhibitors. Cip1 mutants are less virulent on tomato, demonstrating the importance of this effector in apoplastic immunity. Cip1 also inhibits immune protease Pip1, which is known to suppress PtoDC3000 infection, but has a lower affinity for its close homolog Rcr3, explaining why this protein is not recognized in tomato plants carrying the Cf-2 resistance gene, which uses Rcr3 as a co-receptor to detect pathogen-derived protease inhibitors. Thus, this approach uncovered a protease inhibitor of P. syringae, indicating that also P. syringae secretes effectors that selectively target apoplastic host proteases of tomato, similar to tomato pathogenic fungi, oomycetes and nematodes.

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The role of conserved residues of chagasin in the inhibition of cysteine peptidases

Cited by 19 publications

References 16 publications

Pathogenesis of Chagas' Disease: Parasite Persistence and Autoimmunity

Pathogenesis of Chagas' Disease: Parasite Persistence and Autoimmunity

The cathepsin L of Toxoplasma gondii (TgCPL) and its endogenous macromolecular inhibitor, toxostatin

Screen of Non-annotated Small Secreted Proteins of Pseudomonas syringae Reveals a Virulence Factor That Inhibits Tomato Immune Proteases

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