The complete set of SNARE proteins that define membrane compartments and mediate fusion events in Giardia lamblia.

VANINA ELÍAS; RODRIGO QUIROGA; HUGO DANIEL LUJÁN

Woods Hole, Estados Unidos

Congreso; Molecular Parasitology Meeting; 2007

The early branching protist Giardia lamblia is an intestinal parasite that has a simple life cycle, alternating between the vegetative trophozoite and the infective cyst. In higher eukaryotic cells, the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins are the core fusion machinery for intracellular vesicle trafficking and specific SNARE pairing is required for appropriate membrane fusion. To infer the functional role of the SNARE proteins in Giardia, we determined their localization through transfection and expression of the epitope-tagged constructs in vegetative and encysting trophozoites. Our results indicate that each Giardia SNARE localizes to a particular subcellular compartment and that some of them are involved in the regulated secretory pathway occurring during cyst wall formation. By antisense knock-down expression, we also found that most SNAREs are essential for parasite viability, demonstrating the importance of the SNARE proteins in constituting a minimal machinery for vesicle fusion in eukaryotes. Considering that vesicle trafficking in this human pathogen is important for maintenance of infection and disease, our study might facilitate the development of new anti-Giardia drugs using the SNARE proteins as targets