Large-scale proteomic analysis of SUMOylation targets in Trypanosoma cruzi.

BAYONA, J.L.; NAKAYASU, E.S.; ALVAREZ, V.E.; LAVERRIERE, M.; AGUILAR, C.; SOBREIRA, T.P.; CHOI, H.; NESVIZHSKII, A.I.; ALMEIDA, I.C.; CAZZULO, J.J.

Puerto Madryn

Congreso; XLVI Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2010

SUMOylation is a relevant protein post-translational modification in eukaryotes. The C-terminus of proteolytically-activated SUMO is covalently linked to a Lys of the target by an isopeptide bond, by a mechanism that includes an E1-activating enzyme, an E2-conjugating enzyme, and transfer to the target, sometimes with the assistance of a ligase. The modification is reversed by a protease, also responsible for SUMO maturation. A number of proteins have been identified as SUMO targets, participating in the regulation of cell cycle progression, transcription, translation, ubiquitination, and DNA repair. We have reported that the orthologous genes corresponding to the SUMOylation pathway are present in T. cruzi, that the SUMOylation system is functional in the parasite, and defined the requirements for TcSUMO maturation and conjugation. To identify SUMOylation targets and get an insight into their physiological roles we generated transfectant epimastigote lines expressing a double-tagged TcSUMO, and SUMOylated proteins were enriched by tandem affinity chromatography. Over 200 proteins were identified as potential SUMO targets by 2D liquid chromatography-mass spectrometry. Proteomic studies in other organisms have reported that orthologues of T. cruzi putative SUMOylated proteins are similarly modified. So far, we have biochemically validated  metacaspase 3 as SUMOylation substrate.