The Complete set of SNARE proteins that mediate membrana fusion events in Giardia lamblia.

ELIANA VANINA ELÍAS; RODRIGO QUIROGA; HUGO DANIEL LUJÁN

Marine Biological Laboratory, Woods Hole, Maryland, USA

Jornada; Molecular Parasitology Meeting XVIII; 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 cysst. In higher eukaryotic cells, the SNARE (soluble N-ethylmaleimide-sensitive factor-attachment protein receptor) proteins constitue 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 prteins in Giardia, we determined their subcellular localization through transfection and expression of the pitope-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 occuring during cyst wall formation. By antisense knock-down xpression, 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 trafficing in this human pathogen is important for maintainance of infection and disease, our study migh facilitate the development of new anti-Giardia drugs using the SNARE proteins as targets.