Phosphatidylinositol kinase activities in Trypanosoma cruzi epimastigotes.

Phosphatidylinositol (PtdIns) metabolism through phosphatidylinositol kinase (PIKs) activities plays a central role in different signaling pathways. In Trypanosoma cruzi, causative agent of Chagas disease, PIKs have been proposed as target for drug design in order to combat this pathogen. In this work, we studied the classes of PI4K, PIPK and PI3K that could participate in signaling pathways in T. cruzi epimastigote forms. For this reason, we analyzed their enzymatic parameters and detailed responses to avowed kinase inhibitors (adenosine, sodium deoxycholate, wortmannin and LY294002) and activators (Ca(2+), phosphatidic acid, spermine and heparin). Our results suggest the presence and activity of a class III PI4K, a class I PIPK, a class III PI3K previously described (TcVps34) and a class I PI3K. Class I PI3K enzyme, here named TcPI3K, was cloned and expressed in a bacterial system, and their product was tested for kinase activity. The possible participation of TcPI3K in central cellular events of the parasite is also discussed.