Phosphatase activity in Trypanosoma cruzi. Phosphate removal from ATP, phosphorylated proteins and other phosphate compounds

Letelier, María Eugenia; Alliende, Cecilia; González, Julieta; Aldunate, J.; Repetto, Yolanda; Morello, Antonio

doi:10.1016/0305-0491(86)90015-5

Cited by 6 publications

(10 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…On the other hand, we reported [12] obtaining (Ca2+-Mg2+)-ATPase from T. cruzi after epimastigote disruption by abrasion with glass beads. Differences between these ATPase preparations were remarkable, since the enzymes isolated by Frasch et al [42] and Letelier et al [43] required no Mg2+ for Ca2+ stimulation of activity, which, however, was essential for our preparations [12]. On the other hand, after cell disruption of T. cruzi epimastigotes by the abrasion method, Cataldi de Flombaum and Stoppani [44] could reproduce our results.…”

Section: Discussionmentioning

confidence: 54%

A calmodulin-stimulated Ca2+ pump in plasma-membrane vesicles from Trypanosoma brucei; selective inhibition by pentamidine

Benaím

López-Estraño

Docampo

et al. 1993

Biochemical Journal

View full text Add to dashboard Cite

Despite previous reports [McLaughlin (1985) Mol. Biochem. Parasitol. 15, 189-201; Ghosh, Ray, Sarkar and Bhaduri (1990) J. Biol. Chem. 265, 11345-11351; Mazumder, Mukherjee, Ghosh, Ray and Bhaduri (1992) J. Biol. Chem. 267, 18440-18446] that the plasma membrane of different trypanosomatids only contains Ca(2+)-ATPase that does not show any demonstrable dependence on Mg2+, a high-affinity (Ca(2+)-Mg2+)-ATPase was demonstrated in the plasma membrane of Trypanosoma brucei. The enzyme became saturated with micromolar amounts of Ca2+, reaching a Vmax. of 3.45 +/- 0.66 nmol of ATP/min per mg of protein. The Km,app. for Ca2+ was 0.52 +/- 0.03 microM. This was decreased to 0.23 +/- 0.05 microM, and the Vmax. was increased to 6.36 +/- 0.22 nmol of ATP/min per mg of protein (about 85%), when calmodulin was present. T. brucei plasma-membrane vesicles accumulated Ca2+ on addition of ATP only when Mg2+ was present, and released it to addition of the Ca2+ ionophore A23187. In addition, this Ca2+ transport was stimulated by calmodulin. Addition of NaCl to Ca(2+)-loaded T. brucei plasma-membrane vesicles did not result in Ca2+ release, thus suggesting the absence of a Na+/Ca2+ exchanger in these parasites. Therefore the (Ca(2+)-Mg2+)-ATPase would be the only mechanism so far described that is responsible for the long-term fine tuning of the intracellular Ca2+ concentration of these parasites. The trypanocidal drug pentamidine inhibited the T. brucei plasma-membrane (Ca(2+)-Mg2+)-ATPase and Ca2+ transport at concentrations that had no effect on the Ca(2+)-ATPase activity of human or pig erythrocytes. In this latter case, pentamidine behaved as a weak calmodulin antagonist, since it inhibited the stimulation of the erythrocyte Ca(2+)-ATPase by calmodulin.

show abstract

Section: Discussionmentioning

confidence: 54%

A calmodulin-stimulated Ca2+ pump in plasma-membrane vesicles from Trypanosoma brucei; selective inhibition by pentamidine

Benaím

López-Estraño

Docampo

et al. 1993

Biochemical Journal

View full text Add to dashboard Cite

show abstract

“…As the characterization of protein kinases is expanding, a better knowledge of the phosphatase complement of these parasites is essential to understand the complexity and regulation of many processes controlled by phosphorylation (Brenchley et al, 2007). More than 55% of total acid phosphatase activity in T. cruzi is associated with the plasma membrane (Nagakura et al, 1985), but is also present in the lysosomes, cytosol, and mitochondria (Letelier et al, 1986). A membrane-bound microsomal acid phosphatase (optimum pH at 4.0), a soluble cytosolic acid phosphatase with an optimum pH of 5.5, and a soluble cytosolic alkaline phosphatase with an optimum pH of 8.0 have been reported in the epimastigote form of T. cruzi (Letelier et al, 1985).…”

Section: Discussionmentioning

confidence: 99%

“…The homogenates were incubated for 15 min at 37 C in 1 ml of a reaction mixture containing buffer and 10 mM of p-nitrophenylphosphate (p-NPP). The buffers were used at the final concentration of 0.1 M with sodium citrate at pH 3.0, sodium acetate for assays at pH 4.0 and 5.0, Bis-Tris for pH 6.0, Hepes for assays at pH 7.0, and Tris-HCl for pH 8.0 (Letelier et al, 1986). The reaction was initiated by addition of the homogenate and stopped with 1 ml of 1 M NaOH.…”

Section: Enzyme Activity Assaysmentioning

confidence: 99%

“…Trypanosoma cruzi is the etiologic agent of Chagas' disease, which affects 17 million people in Latin America (Dutra et al, 2005). The treatment is ineffective during the chronic stage of the disease, and toxic side effects have been reported (Letelier et al, 1986). Unfortunately, no advances have been achieved toward a more efficient treatment; the current treatment has remained the same since its discovery 3 decades ago (Croft et al, 2005).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Distinct Phosphatase Activity Profiles in Two Strains of Trypanosoma cruzi

Morales-Neto¹,

Hulshof²,

Ferreira³

et al. 2009

Journal of Parasitology

View full text Add to dashboard Cite

Phosphorylation of parasite proteins plays a key role in the process of cell invasion by Trypanosoma cruzi, the etiologic agent of Chagas' disease. In this sense, characterization of parasite kinases and phosphatases could open new possibilities for the rational design of chemotherapeutic agents for the treatment of Chagas' disease. In this work, we analyzed phosphatase activities in T. cruzi homogenates from 2 strains belonging to different lineages and with different resistance to oxidative stress. Tulahuen 2 cells (Lineage I) showed higher phosphatase activities and specificity constants when compared to the Y strain (Lineage II). Tulahuen 2 had an optimum phosphatase activity at pH 4.0 and the Y strain at pH 7.0. In both cases, neutral–basic, but not acid, phosphatase activities were increased in the presence of Mg2+. Although calcium had an inhibitory effect at a pH of 7.0 and 8.0 in the Y strain, this inhibition was restricted to pH 8.0 in the other strain. Different substrates and acid phosphotyrosine and alkaline phosphatase inhibitors exhibited distinct effects on the phosphatase activity of both strains. Our results provide a better understanding of T. cruzi phosphatases and reinforce the notion of heterogeneity among T. cruzi populations.

show abstract

“…Por outro lado, duas atividades fosfatásicas citosólicas permaneciam altas somente durante os primeiros dias de crescimento, 7-8 dias de cultura, que corresponde a fase logartímica de crescimento. Quando essa cultura entrava na fase estacionária da curva de crescimento as duas atividades enzimáticas citosólicas declinavam, estabilizando-se quando alcançava um valor que era em tomo de 60 % abaixo do máximo (Letelier et al, 1986). Esse dado mostra que algumas enzimas revelam diferentes velocidades de hidrólise para o seu substrato dependendo da fase de crescimento.…”

Section: Purificação Parcial Da Atp-difosfohidrolase Por Eletroforeseunclassified

Caracterização de uma ATP-Difosfohidrolase de <i>Trypanosoma cruzi</i>

Nascimento¹

View full text Add to dashboard Cite

À mainha Jose/a, que me deu não apenas à luz, mas também a luz que ilumina o meu caminho."Que a tua Luz possa de alguma maneira iluminar a mente daqueles que acreditam apenas na escuridão da ciência".A painho Pedro e aos meus irmãos Tan, Véio, Lóren, Lon e Bi.Obrigado por vocês serem assim.À minha noiva Carla. ''Nenhum ser se tornará Uno, até que encontre a si mesmo. E isso só será possível, quando ele encontrar outro Ser".Obrigado Carla por você ter tornado-me Uno. AGRADECIMENTOSAo Proi Sergio Verjovski-Almeida que me recebeu em seu laboratório e fez deste um local de aprendizado inestimável, sem o qual ficaria difícil dar continuidade a posteriores desafios na carreira científica. À Prof. Maria Julia Manso Alves, para a qual, sem dúvida alguma, também dirigo os agradecimentos do primeiro parágrafo.Ao Proi Jorge Mauricio David que me iniciou na pesquisa científica.À prof. Marisa Medeiros, que se fez presente em um momento inicial, mas fundamental, para o desenvolvimento do meu mestrado.Ao Prof. Roberto Casadei, que mostrou desde o início uma preocupação pela minha formação e que me fez ver, que nem só de arrogância vive a ciência.Aos colegas de pós-graduação, Marinez, Luiz, Fátima, Jorge, Fernando, Bia, TeIma, Luciano, Lucivanda, Izaura , em fim, à todos que se tomaram, de alguma maneira, parte integrante da minha passagem por esse instituto, tornando-a bem mais agradável.À Marinei Gonçalves e ao Roberto, e de um modo geral a todos os funciónarios técnicos, peças humanas importantíssimas nessa engrenagem chamada pesquisa científica.Ao colega Ricardo Giordano, que dedicou muito do seu tempo e paciência, para ensinar-me técnicas, que apesar de não terem sido relatadas nesse trabalho, foram, sem dúvida alguma, tão importantes quanto o trabalho aqui apresentado.À colega Eveline Vasconcelos, por ter dado-me o suporte técnico necessário ao desenvolvimento desse trabalho, o qual foi de extrema importância para que o mesmo chegasse ao seu término.Aos colegas de laboratório Eduardo, Vitor, Alessandra, Juliana, Roberto, Pautinho, Paolo, André, Melissa, Valéria, Juliana, Jefferson e Ivone. "Que os motivos que nos levaram a partilharmos do mesmo espaço, possam de alguma maneira estenderem-se a outros tantos", Aos amigos Humberto, Newman, Glauber, Lucas, que por serem baianos já justificaria os agradecimentos, mas não sendo isso o bastante, então por estarem presentes aqui, tomando a distância da terra mãe, não tão distante assim.Aos amigos Almir, Carlisvan, Eduardo, Evanilson, Josué, Luciano, Renivaldo, Robison, e Josélia que acreditam e torcem por mim.A todos os amigos distantes, mas não esquecidos, que por motivos culturais e históricos não puderam também fazerem-se distantes, e que vêem em mim uma espécie de "auto-realização". Brener, 1973;Brack, 1968;Dias, 1934; Zeledon et aI., 1977 Há muitas informações a respeito de fosfohidrolases em tripanosomatídeos. Aqui, serão citadas apenas as ATPases julgadas importantes ao trabalho, ou seja, aquelas que de algum modo poderiam mascarar os resultados previstos para a api...

show abstract

Phosphatase activity in Trypanosoma cruzi. Phosphate removal from ATP, phosphorylated proteins and other phosphate compounds

Cited by 6 publications

References 15 publications

A calmodulin-stimulated Ca2+ pump in plasma-membrane vesicles from Trypanosoma brucei; selective inhibition by pentamidine

A calmodulin-stimulated Ca2+ pump in plasma-membrane vesicles from Trypanosoma brucei; selective inhibition by pentamidine

Distinct Phosphatase Activity Profiles in Two Strains of Trypanosoma cruzi

Caracterização de uma ATP-Difosfohidrolase de <i>Trypanosoma cruzi</i>

Contact Info

Product

Resources

About