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Divalent cation hinder the solubilization of a tubulin kinase activity from Trypanosoma cruzi epimastigotes
UZCANGA,GRACIELA; GALáN-CARIDAD,JOSé MANUEL; SUAREZ,KAREM NORIS; BUBIS,JOSé;
Biological Research , 2003, DOI: 10.4067/S0716-97602003000300008
Abstract: trypanosoma cruzi epimastigotes were extracted under various conditions in order to examine the role of divalent cations in the solubilization of microtubule proteins. when epimastigotes were homogenized in the presence of 5 mm mg+2 and 5 mm ca+2, a protein kinase responsible for phosphorylating tubulin, as well as the tubulin that became phosphorylated, remained tightly associated with the parasite particulate and detergent-resistant fractions. on the contrary, tubulin kinase and its substrate were predominantly released into the parasite cytosolic and detergent-soluble fractions, when epimastigotes were extracted in the presence of 5 mm edta and 5 mm egta. these evidences demonstrated a divalent cation-dependent solubilization of the enzyme responsible for the phosphorylation of tubulin in t. cruzi epimastigotes and suggested a tight association between tubulin and this kinase. under all conditions tested, tubulin kinase activity in epimastigote extracts was lower than the addition of the corresponding value in the parasite cytosolic and membranous fractions, suggesting the presence of a kinase inhibitor or regulatory subunit which also seemed to be modulated by divalent cations. additionally, inhibition experiments in the presence of heparin, 2,3-bisphosphoglycerate and gtp established that the parasite tubulin kinase corresponded to a protein kinase ck2
Divalent cation hinder the solubilization of a tubulin kinase activity from Trypanosoma cruzi epimastigotes
GRACIELA UZCANGA,JOSé MANUEL GALáN-CARIDAD,KAREM NORIS SUAREZ,JOSé BUBIS
Biological Research , 2003,
Abstract: Trypanosoma cruzi epimastigotes were extracted under various conditions in order to examine the role of divalent cations in the solubilization of microtubule proteins. When epimastigotes were homogenized in the presence of 5 mM Mg+2 and 5 mM Ca+2, a protein kinase responsible for phosphorylating tubulin, as well as the tubulin that became phosphorylated, remained tightly associated with the parasite particulate and detergent-resistant fractions. On the contrary, tubulin kinase and its substrate were predominantly released into the parasite cytosolic and detergent-soluble fractions, when epimastigotes were extracted in the presence of 5 mM EDTA and 5 mM EGTA. These evidences demonstrated a divalent cation-dependent solubilization of the enzyme responsible for the phosphorylation of tubulin in T. cruzi epimastigotes and suggested a tight association between tubulin and this kinase. Under all conditions tested, tubulin kinase activity in epimastigote extracts was lower than the addition of the corresponding value in the parasite cytosolic and membranous fractions, suggesting the presence of a kinase inhibitor or regulatory subunit which also seemed to be modulated by divalent cations. Additionally, inhibition experiments in the presence of heparin, 2,3-bisphosphoglycerate and GTP established that the parasite tubulin kinase corresponded to a protein kinase CK2
Molecular basis of mammalian cell invasion by Trypanosoma cruzi
Yoshida, Nobuko;
Anais da Academia Brasileira de Ciências , 2006, DOI: 10.1590/S0001-37652006000100010
Abstract: establishment of infection by trypanosoma cruzi, the agent of chagas' disease, depends on a series of events involving interactions of diverse parasite molecules with host components. here we focus on the mechanisms of target cell invasion by metacyclic trypomastigotes (mt) and mammalian tissue culture trypomastigotes (tct). during mt or tct internalization, signal transduction pathways are activated both in the parasite and the target cell, leading to ca2+ mobilization. for cell adhesion, mt engage surface glycoproteins, such as gp82 and gp35/50, which are ca2+ signal-inducing molecules. in t. cruzi isolates that enter host cells in gp82-mediated manner, parasite protein tyrosine kinase as well as phospholipase c are activated, and ca2+ is released from ip3-sensitive stores, whereas in t. cruzi isolates that attach to target cells mainly through gp35/50, the signaling pathway involving adenylate cyclase appears to be stimulated, with ca2+ release from acidocalciosomes. in addition, t. cruzi isolate-dependent inhibitory signals, mediated by mt-specific gp90, may be triggered both in the host cell and the parasite. the repertoire of tct molecules implicated in cell invasion includes surface glycoproteins of gp85 family, with members containing binding sites for laminin and cytokeratin 18, enzymes such as cruzipain, trans-sialidase, and an oligopeptidase b that generates a ca2+-agonist from a precursor molecule.
Molecular basis of mammalian cell invasion by Trypanosoma cruzi  [cached]
Yoshida Nobuko
Anais da Academia Brasileira de Ciências , 2006,
Abstract: Establishment of infection by Trypanosoma cruzi, the agent of Chagas' disease, depends on a series of events involving interactions of diverse parasite molecules with host components. Here we focus on the mechanisms of target cell invasion by metacyclic trypomastigotes (MT) and mammalian tissue culture trypomastigotes (TCT). During MT or TCT internalization, signal transduction pathways are activated both in the parasite and the target cell, leading to Ca2+ mobilization. For cell adhesion, MT engage surface glycoproteins, such as gp82 and gp35/50, which are Ca2+ signal-inducing molecules. In T. cruzi isolates that enter host cells in gp82-mediated manner, parasite protein tyrosine kinase as well as phospholipase C are activated, and Ca2+ is released from I P3-sensitive stores, whereas in T. cruzi isolates that attach to target cells mainly through gp35/50, the signaling pathway involving adenylate cyclase appears to be stimulated, with Ca2+ release from acidocalciosomes. In addition, T. cruzi isolate-dependent inhibitory signals, mediated by MT-specific gp90, may be triggered both in the host cell and the parasite. The repertoire of TCT molecules implicated in cell invasion includes surface glycoproteins of gp85 family, with members containing binding sites for laminin and cytokeratin 18, enzymes such as cruzipain, trans-sialidase, and an oligopeptidase B that generates a Ca2+-agonist from a precursor molecule.
A Soluble Factor from Trypanosoma cruzi Inhibits Transforming Growth Factor-?-Induced MAP Kinase Activation and Gene Expression in Dermal Fibroblasts  [PDF]
G. Adam Mott, Jaime A. Costales, Barbara A. Burleigh
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0023482
Abstract: The protozoan parasite Trypanosoma cruzi, which causes human Chagas' disease, exerts a variety of effects on host extracellular matrix (ECM) including proteolytic degradation of collagens and dampening of ECM gene expression. Exposure of primary human dermal fibroblasts to live infective T. cruzi trypomastigotes or their shed/secreted products results in a rapid down-regulation of the fibrogenic genes collagenIα1, fibronectin and connective tissue growth factor (CTGF/CCN2). Here we demonstrate the ability of a secreted/released T. cruzi factor to antagonize ctgf/ccn2 expression in dermal fibroblasts in response to TGF-?, lysophosphatidic acid or serum, where agonist-induced phosphorylation of the mitogen-activated protein (MAP) kinases Erk1/2, p38 and JNK was also inhibited. Global analysis of gene expression in dermal fibroblasts identified a discrete subset of TGF-?-inducible genes involved in cell proliferation, wound repair, and immune regulation that are inhibited by T. cruzi secreted/released factors, where the genes exhibiting the highest sensitivity to T. cruzi are known to be regulated by MAP kinase-activated transcription factors. Consistent with this observation, the Ets-family transcription factor binding site in the proximal promoter region of the ctgf/ccn2 gene (?91 bp to ?84 bp) was shown to be required for T. cruzi-mediated down-regulation of ctgf/ccn2 reporter expression. The cumulative data suggest a model in which T. cruzi-derived molecules secreted/released early in the infective process dampen MAP kinase signaling and the activation of transcription factors that regulate expression of fibroblast genes involved in wound repair and tissue remodelling, including ctgf/ccn2. These findings have broader implications for local modulation of ECM synthesis/remodelling by T. cruzi during the early establishment of infection in the mammalian host and highlight the potential for pathogen-derived molecules to be exploited as tools to modulate the fibrogenic response.
The increase of adenylate kinase activity in the blood can control aggregation of platelets in coronary or peripheral arterial ischemia  [PDF]
Bozena Studzińska, Anna Seroka, Marta Lepicka, Katarzyna Roszek, Michal Komoszyński
Health (Health) , 2010, DOI: 10.4236/health.2010.23035
Abstract: Activation and aggregation of blood platelets is crucial for hemostasis and thrombosis. In the vascular system adenine nucleotides are important signaling molecules playing a key role in hemostasis. ADP was the first low molecular weight agent recognized to cause blood platelets activation and aggregation. NTPDases and adenylate kinase (AK) are the main enzymes involved in metabolism of extracellular adenine nucleotides. The majority of studies concentrated on the role of NTPDase1 (apyrase) in the inhibition of platelets aggregation. Up to now, there are still insufficient data concerning the role of AK in this process. We found that adenylate kinase activity in the serum of patients with myocardial infarction is significantly increased when compared to the healthy volunteers. The elevated activity of AK is connected to appearance of another isoform of that enzyme, expressed in patients with myocardial infarction. The influence of AK on the pig blood platelets aggregation induced by 20 μM ADP or 7.5 μg/ml rat collagen was examined. 1U of adenylate kinase added to platelet-rich plasma (PRP) before ADP or collagen, inhibited the platelets aggregation. One minute after induction of platelets activation by ADP as much as 5U of adenylate kinase was necessary to stop the platelet aggregation. In the case of collagen activated aggregation, only 2U of AK added 1 or 5 minutes after initiation of the aggregation process were sufficient for disaggregation of platelets. The increase of ATP: ADP ratio is probably responsible for the initiation of disaggregation process. We conclude that adenylate kinase is involved in regulation of plate-lets aggregation. Anticoagulative role of AK indicates the possibility of using this enzyme in the treatment of cardiovascular diseases.
Profiling the Trypanosoma cruzi Phosphoproteome  [PDF]
Fabricio K. Marchini, Lyris M. F. de Godoy, Rita C. P. Rampazzo, Daniela P. Pavoni, Christian M. Probst, Florian Gnad, Matthias Mann, Marco A. Krieger
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0025381
Abstract: Protein phosphorylation is a reversible post-translational modification essential for the regulation of several signal transduction pathways and biological processes in the living cell. Therefore, the identification of protein phosphorylation sites is crucial to understand cell signaling control at the molecular level. Based on mass spectrometry, recent studies have reported the large-scale mapping of phosphorylation sites in various eukaryotes and prokaryotes. However, little is known about the impact of phosphorylation in protozoan parasites. To in depth characterize the phosphoproteome of Trypanosoma cruzi, a parasite of the Kinetoplastida class, protein samples from cells at different phases of the metacyclogenesis – differentiation process of the parasites from non-infective epimastigotes to infective metacyclic trypomastigotes - were enriched for phosphopeptides using TiO2 chromatography and analyzed on an LTQ-Orbitrap mass spectrometer. In total, 1,671 proteins were identified, including 753 phosphoproteins, containing a total of 2,572 phosphorylation sites. The distribution of phosphorylated residues was 2,162 (84.1%) on serine, 384 (14.9%) on threonine and 26 (1.0%) on tyrosine. Here, we also report several consensus phosphorylation sequence motifs and as some of these conserved groups have enriched biological functions, we can infer the regulation by protein kinases of this functions. To our knowledge, our phosphoproteome is the most comprehensive dataset identified until now for Kinetoplastida species. Here we also were able to extract biological information and infer groups of sites phosphorylated by the same protein kinase. To make our data accessible to the scientific community, we uploaded our study to the data repositories PHOSIDA, Proteome Commons and TriTrypDB enabling researchers to access information about the phosphorylation sites identified here.
The cell surface of Trypanosoma cruzi
Souza, Wanderley de;Souto-Padrón, Thais;
Memórias do Instituto Oswaldo Cruz , 1984, DOI: 10.1590/S0074-02761984000500003
Abstract: the cell surface of trypanosomatids is formed by the plasma membrane and a layer of sub-pellicular microtubules which are connected to the plasma membrane. the plasma membrane is composed by proteins, lipids and carbohydrates which form the glycocalix. in this paper we will review briefly aspects related to the organization of the cell surface of trypanosoma cruzi.
Trypanosoma cruzi: circulating antigens
Bongertz, V.;Hungerer, Klaus-Dieter;Galv?o-Castro, Bernardo;
Memórias do Instituto Oswaldo Cruz , 1981, DOI: 10.1590/S0074-02761981000100008
Abstract: circulating antigens were detected in sera of mice experimentally infected with a high close of trypanosoma cruzi by reaction with sera from chronically infected mice. the immunodiffusion reaction between homologous acute and chronic sera produced four precipitation lines. by reaction with chronic mouse serum, circulating antingens were detected in sera from heavily infected hamsters, dogs, rabbits and in sera from chagasic patients. a reaction was also found in urine from acutely infected mice and dogs. trypanosoma cruzi exoantigen was detected in trypanosome culture medium and in the supernatant of infected cell cultures. attempts to isolate the antigens are described.
Activation and conformational changes of adenylate kinase in urea solution
Hongjie Zhang,Xianming Pan,Junmei Zhou,Kihara Hiroshi
Science China Life Sciences , 1998, DOI: 10.1007/BF02895098
Abstract: The activation and inactivation of adenylate kinase during deneturation in urea are compared with changes in UV absorbance at 287 nm. CD spectrum change at 222 nm, fluorescence intensity of ANS biding and small angle of X-ray scattering. At 1 mol/L, of urea the enzyme is activated 1.5-fold companied with a subtie decressing of its second structure, whereas its tertiary structure is fairly resistant to denaturation. By comparing the studies of the crystal structure and the mechanism of the catalysis of adenylste kinase, the activation is believed to result the effect that low concentration of urea increases the flexibility of the active site of the enzyme. This suggestion was confirmed by the results of the fluorescence intensity changes of ANS binding to adenylate kinase versus the concentration of urea.
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