Intracellular membrane fusion events are mediated by conserved proteins of the snares family in Giardia lamblia

NATALIA GOTTIG; VANINA ELIAS; A NEIMAN; HUGO DANIEL LUJÁN; THEODORE NASH; MARIA CAROLINA TOUZ

Mendoza - Argentina

Congreso; VII Congreso Argentino Protozoología y Enfermedades parasitarias; 2005

Sociedad Argentina de Protozoología

The early branching protist G.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. We identify and characterize seven putative SNAREs proteins,three of the vesicle-associated membrane protein family and four of the Syntaxin family in Giardia.To infer their functional role,we determined their localitation through the transfection and expression of epitope-tagged constructs in Giardia trophozoites.Using Northern blot assays,we also analyzed their level of expression during the life cycle of Giardia and possible interactions between them by yeast two-hybrid analysis.Our result show that these seven Giardia SNARE localize to different subcellular compartments,are essential for parasite viability, and show specific SNARE-SNARE interactions.These results are of considerable biological interest because they contribute to the understanding of the biology of the eukaryotic origins,particulary of the endomembrane-mediated system of protein modification, sorting, and transport. Moreover, considering that vesicle trafficking in this human pathogen is important in maintaining infection and disease, our study will allow the development of new specific drugs using the SNAREs proteinas targets.