INIMEC - CONICET   05467
INSTITUTO DE INVESTIGACION MEDICA MERCEDES Y MARTIN FERREYRA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
SUMOYLATION IN GIARDIA LAMBLIA: A COMPLEX POST-TRANSLATIONAL MODIFICATION IN ONE OF THE MOST PRIMITIVE EUKARYOTIC CELLS
Autor/es:
VRANYCH CV; MERINO MC; RIVERO MR; TOUZ MC; ROPOLO AS
Lugar:
Ascochinga
Reunión:
Congreso; XXIV Reunión Científica Anual Sociedad Argentina de Protozoología.; 2010
Resumen:
Post-translational modifications are rapid, efficient and reversible means of regulating protein stability, interactions, localization, and function. Interaction with SUMO (small ubiquitin-like modifier) is one of the most complex and interesting studied mechanisms of protein regulation in eukaryotes, with diverse consequences and targets. However, little is know about how this system is used by parasites although it has been already described in Toxoplasma gondii and Plasmodium falciparum. The complex life cycle of parasites, in general, requires dynamic protein expression and gene regulation to exploit efficaciously the different environments. In contrast to eight members in Arabidopsis thaliana and four in mammals, and similar to what happens in Saccharomyces cerevisiae and Drosophila melanogaster we found in Giardia lamblia a single SUMO gene corresponding to Sentrin, a homologue protein to Human SUMO1. After amplification by PCR we used this gene and we transfected Giardia trophozoites. Inmunofluorescense assays showed that Sentrin protein localized mainly in the cell cytoplasm, though also in the flagella and surrounding the nuclei, even inside it in some trophozoites. By Western Blot we could observe several sumoylated proteins, but at this time, only arginine deiminase (an enzyme involved in survival and antigenic variation in Giardia) was confirmed as a sumoylated substrate by Western Blot and Inmunoprecipitation. Nevertheless, though the Sumoylation system appears to be a functionally pathway for protein modification in Giardia lamblia only one component of the Sumoylation cascade was found in its genome: the sentrin protease. After amplification by PCR, we transfected Giardia trophozoites and we determined the subcellular localization of this protein that presented mainly sub-nuclear localization, as some proteases of other eukaryotics. The study of the Sumoylation process, not characterized still in Giardia, might not only provide insight into the biology of this important intestinal parasite but also contribute to the understanding of this novel post-translational modification in the evolution of eukaryotic cells.