Localization of the phosphodiesterase TcrPDEC2 and its role in osmoregulation in Trypanosoma cruzi

SCHOIJET, AC; DOCAMPO R; MIRANDA K; DE SOUZA W; TORRES HN; FLAWIÁ MM; ALONSO GD

San MIguel de Tucumán -Argentina

Congreso; XLV Reunión anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB),; 2009

SAIB

Trypanosoma cruzi, the causative agent of Chagas disease, possesses a complex life cycle during which it encounters extreme fluctuations in external osmolarity. It has been found that cyclic AMP levels increase when parasites are subjected to hyposmotic stress. Recently, we have described a cAMP-specific phosphodiesterase, TcrPDEC2, which possesses a FYVE domain, which is known to bind to membranes enriched in phosphatidylinositol 3-phosphate (PI 3-P). In addition, we have characterized TcVps34, the first phosphatidylinositol 3-kinase (PI3K) described in T. cruzi. In this work, we report a functional role for TcrPDEC2 in osmoregulation in T. cruzi. Treatment with TcrPDEC2 inhibitors affects their capability to respond to hyposmotic stress. Moreover, TcrPDEC2 showed to be localized in the contractile vacuole complex (CVC), a key organelle involved in the release of water. Furthermore, in TcVps34-overexpressing parasites this PDE is localized not only in the CVC but also in other intracellular structures, suggesting a possible role of TcVps34 in TcrPDEC2 localization. Finally, we demonstrated that transgenic parasites without the FYVE domain do not have phosphodiesterase activity. Taken together, these results show that TcrPDEC2 plays a prominent role in vital processes such as osmoregulation and reveal the importance of the FYVE domain for the functionality of this enzyme.