Protein phosphatase 2A plays a crucial role in Giardia lamblia differentiation
Davids, Barbara J.
Birkeland, Shanda R.
Cipriano, Michael J.
Preheim, Sarah P.
Svard, Staffan G.
McArthur, Andrew G.
Gillin, Frances D.
MetadataShow full item record
The ability of Giardia lamblia to undergo two distinct differentiations in response to physiologic stimuli is central to its pathogenesis. The giardial cytoskeleton changes drastically during encystation and excystation. However, the signal transduction pathways mediating these transformations are poorly understood. We tested the hypothesis that PP2A, a highly conserved serine/threonine protein phosphatase, might be important in giardial differentiation. We found that in vegetatively growing trophozoites, gPP2A-C protein localizes to basal bodies/centrosomes, and to cytoskeletal structures unique to Giardia: the ventral disk, and the dense rods of the anterior, posterior-lateral, and caudal flagella. During encystation, gPP2A-C protein disappears from only the anterior flagellar dense rods. During excystation, gPP2A-C localizes to the cyst wall in excysting cysts but is not found in the wall of cysts with emerging excyzoites. Transcriptome and immunoblot analyses indicated that gPP2A-C mRNA and protein are upregulated in mature cysts and during the early stage of excystation that models passage through the host stomach. Stable expression of gPP2A-C antisense RNA did not affect vegetative growth, but strongly inhibited the formation of encystation secretory vesicles (ESV) and water-resistant cysts. Moreover, the few cysts that formed were highly defective in excystation. Thus, gPP2A-C localizes to universal cytoskeletal structures and to structures unique to Giardia. It is also important for encystation and excystation, crucial giardial transformations that entail entry into and exit from dormancy.
Author Posting. © The Authors, 2006. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Molecular and Biochemical Parasitology 152 (2007): 80-89, doi:10.1016/j.molbiopara.2006.12.001.
Showing items related by title, author, creator and subject.
GiardiaDB and TrichDB : integrated genomic resources for the eukaryotic protist pathogens Giardia lamblia and Trichomonas vaginalis Aurrecoechea, Cristina; Brestelli, John; Brunk, Brian P.; Carlton, Jane M.; Dommer, Jennifer; Fischer, Steve; Gajria, Bindu; Gao, Xin; Gingle, Alan; Grant, Greg; Harb, Omar S.; Heiges, Mark; Innamorato, Frank; Iodice, John; Kissinger, Jessica C.; Kraemer, Eileen; Li, Wei; Miller, John A.; Morrison, Hilary G.; Nayak, Vishal; Pennington, Cary; Pinney, Deborah F.; Roos, David S.; Ross, Chris; Stoeckert, Christian J.; Sullivan, Steven; Treatman, Charles; Wang, Haiming (Oxford University Press, 2008-09-29)GiardiaDB (http://GiardiaDB.org) and TrichDB (http://TrichDB.org) house the genome databases for Giardia lamblia and Trichomonas vaginalis, respectively, and represent the latest additions to the EuPathDB (http://EuPathDB.org) ...
Prabhu, Anjali; Morrison, Hilary G.; Martinez, Charles R.; Adam, Rodney D. (2006-12-04)Giardia trophozoites are polyploid and have five chromosomes. The chromosome homologues demonstrate considerable size heterogeneity due to variation in the subtelomeric regions. We used clones from the genome project with ...
The transcriptional response to encystation stimuli in Giardia lamblia is restricted to a small set of genes Morf, Laura; Spycher, Cornelia; Rehrauer, Hubert; Fournier, Catharine Aquino; Morrison, Hilary G.; Hehl, Adrian B. (2010-07)The protozoan parasite Giardia lamblia undergoes stage-differentiation in the small intestine of the host to an environmentally resistant and infectious cyst. Encystation involves secretion of an extracellular matrix ...