INGEBI   02650
INSTITUTO DE INVESTIGACIONES EN INGENIERIA GENETICA Y BIOLOGIA MOLECULAR "DR. HECTOR N TORRES"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
TcrPDEA1, an unusual cAMP-specific phosphodiesterase from Trypanosoma cruzi.
Autor/es:
SCHOIJET, A.C.; TORRES, H.N.; FLAWIÁ, M.M.; ALONSO, G.D.
Lugar:
Rosario. Santa Fe, Argentina. Noviembre de 2006.
Reunión:
Congreso; XLII Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular.; 2006
Institución organizadora:
SAIB
Resumen:
Cyclic nucleotide phosphodiesterases (PDEs) catalyze the degradation of cAMP and cGMP, and by controlling the levels of these second messengers regulate numerous cellular processes. In particular, the complexity of the life cycle of Trypanosoma cruzi requires that this parasite must sense, and rapidly adapt to different environments in its mammalian host and the insect vector. Cyclic nucleotide signal could be an important modulator of such changes, thus cAMP has been shown to downregulate cell proliferation and differentiation in T. cruzi. In the present work, we report the identification of TcrPDEA1, a novel phosphodiesterase from T. cruzi. This enzyme shows homology with PDE1 subfamily members, is coded by a single copy gene and its sequence contains no regulatory domains outside of the catalytic region. TcrPDEA1 was able to complement a yeast mutant strain deficient in PDEs genes and displayed an unusual high Km value of about 200 ƒÝM for cAMP. The enzyme activity decrease according to the incubation time in the presence of EDTA and in a dose¡¦ dependent form. Once the enzyme was inactivated, the addition of Mg2+ did not restore its activity. It is noteworthy that TcrPDEA1 was not inhibited by several PDE inhibitors even at high concentrations. Moreover, TcrPDEA1 activity was not stimulated by cGMP, indicating that this enzyme is specific for cAMP.