title: Trypanosoma rangeli: a possible role for ecto-phosphatase activity on cell proliferation.
abstract: Here we demonstrate for the first time that growth of Trypanosoma rangeli, a protozoa parasite, is strongly dependent on the presence of inorganic phosphate (Pi) in the culture medium and that the replacement of the inorganic phosphate in the culture medium by beta-glycerophosphate, a substrate for phosphatases lead the cells to achieve its maximal growth. The ecto-phosphatase activity present on the external surface of T. rangeli decreased during the growth phase of the parasite, suggesting that this enzyme could be important for the development. Accordingly, the inhibition of this ecto-phosphatase activity by sodium orthovanadate also inhibited the proliferation of T. rangeli. Parasites maintained in a Pi-starved culture medium (2 mM Pi) had 4-fold more ecto-phosphatase activity as compared to parasites maintained in a Pi-supplemented culture medium (50 mM Pi). Altogether, these results presented here suggest that this ecto-phosphatase activity leads to hydrolysis of phosphorylated compounds present in the extracellular medium, which could contribute to the acquisition of inorganic phosphate during the development of T. rangeli epimastigotes.
authors.affiliation: Laboratório de Bioquímica Celular, Instituto de Bioquímica Medica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, CCS, bloco H, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ, Brazil.
authors.forename: André L
authors.initials: AL
authors.lastname: Fonseca-de-Souza
authors.forename: Claudia Fernanda
authors.initials: CF
authors.lastname: Dick
authors.forename: André Luiz Araújo
authors.initials: AL
authors.lastname: dos Santos
authors.forename: Fábio Vasconcelos
authors.initials: FV
authors.lastname: Fonseca
authors.forename: José Roberto
authors.initials: JR
authors.lastname: Meyer-Fernandes
mesh_terms: D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D003470:Culture Media; D010710:Phosphates / Q000378:metabolism / Q000494:pharmacology*; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014345:Trypanosoma / Q000166:cytology / Q000201:enzymology / Q000254:growth & development*
chemical_list: D003470:Culture Media; D010710:Phosphates; D010749:Phosphoprotein Phosphatases