Role of Palmitoylation during Giardia lamblia Encystation

MERINO M.C. ; VRANYCH C.V.; MIRAS S.L.; TOUZ M.C.; RÓPOLO A.S.

Congreso; 47th Annual Meeting. Argentine Society for Biochemistry and Molecular Biology Research; 2011

A key step in the life cycle of G. lamblia is the differentiation of thetrophozoites into cysts. This process is induced in response to hostspecific factors such as high levels of bile, low levels of cholesteroland a basic pH. One of the early events that occur during encystationis the synthesis of cyst wall proteins (CWP). Post-translationalmodifications (PTM) such as palmitoylation, are important toregulate molecular mechanisms involved in cell homeostasis andintracellular signaling. It has been shown that Variant-specificsurface proteins of G. lamblia are palmitoylated, and the enzymeresponsible for this activity has been characterized. However, therole of palmitoylation in encystation has not been reported yet. So,the aim of this work is to elucidate the role of this PTM inencystation in G. lamblia. We observed that when palmitoylation isinhibited by adding 2-Fluoro palmitic acid to the encystation mediathe percentage of cells expressing CWP1+ decreased. Moreover, weobserved an increase of CWP1+ parasites in encysting G. lambliatrophozoites that overexpressed a palmitoyl transferase, comparedto wild type G. lamblia. Due to the many intracellular signalsinvolved in the encystation process is possible that PTM such aspalmitoylation have an important role. Further studies are needed tofind out the molecular mechanisms in which palmitoylation may beinvolved.