title: Biochemical characterization of a protein tyrosine phosphatase from Trypanosoma cruzi involved in metacyclogenesis and cell invasion.
abstract: Protein tyrosine phosphatases (PTPs) form a large family of enzymes involved in the regulation of numerous cellular functions in eukaryotes. Several protein tyrosine phosphatases have been recently identified in trypanosomatides. Here we report the purification and biochemical characterization of TcPTP1, a protein tyrosine phosphatase from Trypanosoma cruzi, the causing agent of Chagas' disease. The enzyme was cloned and expressed recombinantly in Escherichia coli and purified by Ni-affinity chromatography. Biochemical characterization of recombinant TcPTP1 with the PTP pseudo-substrate pNPP allowed the estimation of a Michaelis-Menten constant K(m) of 4.5mM and a k(cat) of 2.8s(-1). We were able to demonstrate inhibition of the enzyme by the PTP1b inhibitor BZ3, which on its turn was able to accelerate the differentiation of epimastigotes into metacyclic forms of T. cruzi induced by nutritional stress. Additionally, this compound was able to inhibit by 50% the infectivity of T. cruzi trypomastigotes in a separate cellular assay. In conclusion our results indicate that TcPTP1 is of importance for cellular differentiation and invasivity of this parasite and thus is a valid target for the rational drug design of potential antibiotics directed against T. cruzi.
authors.affiliation: Departamento de Biofísica, Universidade Federal de São Paulo, Rua Botucatu 862, 04023-062 São Paulo, Brazil.
authors.forename: Gloria
authors.initials: G
authors.lastname: Gallo
authors.forename: Thiago Cesar Prata
authors.initials: TC
authors.lastname: Ramos
authors.forename: Fernanda
authors.initials: F
authors.lastname: Tavares
authors.forename: Antonio A
authors.initials: AA
authors.lastname: Rocha
authors.forename: Emerson
authors.initials: E
authors.lastname: Machi
authors.forename: Sergio
authors.initials: S
authors.lastname: Schenkman
authors.forename: Diana
authors.initials: D
authors.lastname: Bahia
authors.forename: João Bosco
authors.initials: JB
authors.lastname: Pesquero
authors.forename: Martin
authors.initials: M
authors.lastname: Würtele
mesh_terms: D002453:Cell Cycle; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry* / Q000235:genetics; D014349:Trypanosoma cruzi / Q000201:enzymology* / Q000472:pathogenicity*
chemical_list: D017027:Protein Tyrosine Phosphatases