title: Protein kinase A activity is associated with metacyclogenesis in Leishmania amazonensis.
abstract: Because of the importance of cell signalling processes in proliferation and differentiation, the adenylate cyclase pathway was studied, specifically the protein kinase A (PKA) in Leishmania amazonensis. The PKAs of soluble (SF) and enriched membrane fractions (MF) from infective/non-infective promastigotes and axenic amastigotes were assayed. In order to purify the PKA molecule, fractions were chromatographed on DEAE-cellulose columns and the phosphorylative activity was evaluated using [gamma(32)P]-ATP as the phosphate source. These experiments were performed in the presence of cyclic adenosine monophosphate (cAMP) and an inhibitor of PKA. Our data demonstrated that the PKA activity was significantly higher (about two times) in SF from promastigotes with a high concentration of metacyclic forms, when compared with the non-infective promastigotes, suggesting an association of this activity and the metacyclogenesis process. A discrete phosphorylative activity in axenic amastigotes was observed. As the adenylate cyclase/cAMP pathway would be involved in the parasite-host interiorization, the PKA activity may constitute a good intracellular target for studies of leishmanicidal drugs.
authors.affiliation: Department of Immunology, Oswaldo Cruz Institute, 21045-900 Rio de Janeiro, RJ, Brazil. genestra@ioc.fiocruz.br
authors.forename: Marcelo
authors.initials: M
authors.lastname: Genestra
authors.forename: Léa
authors.initials: L
authors.lastname: Cysne-Finkelstein
authors.forename: Leonor
authors.initials: L
authors.lastname: Leon
mesh_terms: D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism; D007894:Leishmania mexicana / Q000201:enzymology* / Q000254:growth & development; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D015800:Protozoan Proteins / Q000032:analysis
chemical_list: D047428:Protein Kinase Inhibitors; D015800:Protozoan Proteins; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D006152:Cyclic GMP