- Glucosylceramide Synthase in parasites. A key enzyme of the glycosphingolipid pathway

PIÑERO, T.A.,; LANDONI, M; SOPRANO L; KATZIN A.M; DUSCHAKV.G; COUTO A.S

Madryn-Chubut

Congreso; XLVI Reunión Anual de la SAIB.; 2010

SAIB

GLUCOSYLCERAMIDE SYNTHASE IN PARASITES, A KEY ENZYME OF THE GLYCOSPHINGOLIPID PATHWAY   Piñero, T.A.1, Landoni, M.1, Soprano, A.M.Katzin3, M.I.2, DuschakV.G.2 and Couto A.S.1 1CIHIDECAR, FCEN-UBA, 2Inst.Nac.Parasit., ANLIS, Argentina, 3Inst. Cs. Biomédicas, USP, Brasil.   Sphingolipids are important components of eukaryotic cells, many of which function as bioactive signaling molecules. Although for mammalian cells most metabolic products of the sphingolipid via have been largely studied and a lot of the enzymes involved have been well-characterized, the panorama in parasitic protozoa is practically unknown. The core structure of the glycosphingolipids, glucosylceramide, is synthesized by a UDP-glucose: ceramide glucosyltransferase (GCS). In a previous work, we have shown the presence of an active GCS enzyme in the intraerythrocytic stages of P. falciparum with a substrate specificity different from that of the mammalian counterpart. Later on we showed that epimastigote forms of Trypanosoma. cruzi present an active GCS with the same substrate specificity of the mammalian enzyme. GCS purified from T. cruzi was used to obtain a specific polyclonal antibody developed in mice. This antibody was able to detect the presence of GCS in lysates of P. falciparum, Toxoplasma gondii, Leishmania amazoniensis and Trypanosoma brucei. Furthermore, activity assays with NBD-Ceramide and NBD-Dihydroceramide were performed using lysates from the different parasites as the enzyme source. Differences between this key enzyme of the glycosphingolipid pathway and the mammalian enzyme would allow considering GCS as a new chemotherapeutic target.  Supported by UBA-CONICET-ANPCYT