INIMEC - CONICET   05467
INSTITUTO DE INVESTIGACION MEDICA MERCEDES Y MARTIN FERREYRA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Sorting role of the perinuclear region and ER in Giardia lamblia.
Autor/es:
ZAMPONI N; FELIZIANI C; MIRAS S; LANFREDI-RANGEL; TOUZ MC
Reunión:
Congreso; SAIB; 2012
Resumen:
The unicellular parasite Giardia lamblia belongs to the
Diplomonads, a group which belongs to the earliest branches in
eukaryotic evolution. One of the most striking characteristics of
Giardia is the presence of protein sorting even though it lacks a
morphological discernible Golgi apparatus. By using bodipy FLC5-
ceramide, a marker for Golgi apparatus, we showed that the
membrane network comprised by the nuclear envelope and the
endoplasmic reticulum (ER) possesses Golgi characteristics in both
growing and encysting trophozoites. DAB photooxidation-coupled
MET showed that ceramide accumulates specifically at the
perinuclear region of the cell, a very dynamic zone, sensitive to
brefeldin A treatment and to low temperature exposure. During
encystation, there was a remarkable change in the endomembrane
system, with ceramide progressively accumulating at the nuclear
membrane and ER exit-sites (ERES), from which we observed that
secretory granules are formed de novo. This accumulation at the
ERES was found also to be sensitive to brefeldinAtreatment, which
causes the reabsorption of the secretion material back to the ER,
although some fully formed vesicles remained, and were entirely
separated from the ER. Altogether, these results suggest that the
perinuclear region and ER play an important role in protein and
membrane sorting in this unique eukaryotic cell.