Palmitoylation in Giardia lamblia: possible palmitoyl transferases and target proteins

MERINO MC; VRANYCH CV; MIRAS S; TOUZ MC; ANDREA SILVANA ROPOLO

Mar del Plata

Congreso; IX Congreso Argentino de Protozoología y Enfermedades Parasitarias; 2011

Sociedad Argentina de Protozoología

A key step in the life cycle of G. lamblia is the differentiation of the trophozoites into cysts. This process is induced in response to host-specific factors such as high levels of bile, low levels of cholesterol and a basic pH. One of the early events that occur during encystation is the synthesis of cyst wall proteins (CWP). Post-translational modifications (PTM) such as palmitoylation, are important to regulate molecular mechanisms involved in cell homeostasis and intracellular signaling. It has been shown that Variant-specific surface proteins of G. lamblia are palmitoylated, and the enzyme responsible for this activity has been characterized. However, the role of palmitoylation in encystation has not been reported yet. So, the aim of this work is to elucidate the role of this PTM in encystation in G. lamblia. We observed that when palmitoylation is inhibited by adding 2-fluoro-palmitic acid to the encysting media the percentage of cells expressing CWP1 decreased. Moreover, we observed an increase of CWP1+ parasites in encysting G. lamblia trophozoites that overexpressed a palmitoyl transferase, compared to wild type G. lamblia. Due to the many intracellular signals involved in the encystation process it is possible that PTM such as palmitoylation have an important role. Further studies are needed to find out the molecular mechanisms in which palmitoylation may be involved.