Secretory granule biogenesis and the organization of membrane compartements via SNARE proteins in Giardia lamblia.

ELIAS, VANINA ELIANA; GOTTIG, NATALIA; QUIROGA, RODRIGO; LUJAN, HUGO DANIEL

Giardia and Cryptosporidium: From Molecules to Disease.

CABI Publishing

Lugar: Wallingford, Oxfordshire, United Kingdom.; Año: 2009; p. 409 - 417

Giardia lambia trophozoites lack organelles typical of higher eukaryotes such as
mitochondria, peroxisomes and compartments involved in intracellular protein traffick-
ing and secretion, the Golgi apparatus and secretory granules. Nevertheless, the minimal
machinery for protein transport and sorting is present in this parasite. When Giardia
undergoes encystation, the biogenesis of secretory organelles necessary to transport cyst
wall constituents to the cell surface takes place. Although both constitutive and regulated
pathways for protein secretion exist in Giandia, little is known about the molecules and
mechanisms specifically involved in vesicular docking and fusion. In higher eukaryotes,
soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) of the
vesicle-associated membrane protein (tVAMP) and syntaxin proteins play an essential role
in these processes through the formation of complexes between proteins present on donor
and target membranes. Recent studies in both vegetative and encysting trophozoites
have provided interesting information regarding the secretory pathway of this important
pathogen.