Sterol biosynthesis compartmentalization in Trypanosoma cruzi

PORTAL PATRICIO; FLAWIÁ MIRTHA; PAVETO CRISTINA

Potrero de los Funes, San Luis

Congreso; XLVII Reunión anual de la Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular; 2011

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Sterol-enriched membrane microdomains are involved in many vital cellular processes as endocytosis, replication, compartmentalization and signaling. CYP51, a Cytochrome P450 (CYP) enzyme is a key enzyme in sterol synthesis present in Trypanosomatids. Moreover, ergosterol biosynthesis pathway is considered to be a selective drug target in Fungi, Leishmania and Trypanosoma, since their mammalian host use cholesterol instead. TcCPR-A, TcCPR-B and TcCPR-C are members of putative Cytochrome P450 reductases (CPR) family in T. cruzi. The recombinant proteins TcCPR-B and TcCPR-C expressed in E. coli were able to complement CYP activities in an in vitro system. Moreover, ergosterol content was significantly increased in TcCPR-B and C overexpressing parasites. We present here the results of complementation experiments showing that the introduction of T. cruzi CPR-B gene into a cpr knock-out Saccharomyces cerevisiae strain (cpr-) WRDelta can restore the yeast normal growth. Interestingly, immunofluorescence studies in T. cruzi localize these enzymes to different subcellular compartments. On the contrary, TcCPR-A overexpression was lethal, displaying aberrant cells, with abnormal morphology and ultrastructural alterations.