Fine structure of the biogenesis of Giardia lamblia encystation secretory vesicles

Lanfredi-Rangel, Adriana; Attias, Márcia; Reiner, David S.; Gillin, Frances D.; Souza, Wanderley de

doi:10.1016/s1047-8477(03)00123-0

Cited by 44 publications

(36 citation statements)

References 46 publications

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“…6B) and the lack of CWP cargo in the ER cisternae. The characteristic DTTinduced ESV morphology was reminiscent of very early stages of ESV development between 2 and 3 h post-encystation and may correspond to the so-called clefts reported in EM studies (10). This implied that the spherical shape of ESVs in later phases of encystation was indicative of a complete or at least more advanced state of cargo maturation and maintained actively.…”

Section: Esv Morphology Is Determined By Cargosupporting

confidence: 53%

“…The exact mechanism of this export is still elusive, however. The available data support two nonmutually exclusive models for ESV genesis: (i) lateral segregation and concentration of cyst wall material in specialized ER subcompartments (10), and/or (ii) export of cyst wall material in COPIIcoated transport vesicles that give rise to ESVs by homotypic fusion (17). In any case, analogous to the generation of vesicular tubular clusters and cis-Golgi compartments, formation of ESVs seems to require the small GTPase Sar1p 3 and thus represents a unique form of Golgi neogenesis.…”

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confidence: 59%

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Organelle Proteomics Reveals Cargo Maturation Mechanisms Associated with Golgi-like Encystation Vesicles in the Early-diverged Protozoan Giardia lamblia

Štefanić

Palm

Svärd

et al. 2006

Journal of Biological Chemistry

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During encystationGiardia trophozoites secrete a fibrillar extracellular matrix of glycans and cyst wall proteins on the cell surface. The cyst wall material is accumulated in encystation-specific vesicles (ESVs), specialized Golgi-like compartments generated de novo, after export from the endoplasmic reticulum (ER) and before secretion. These large post-ER vesicles neither have the morphological characteristics of Golgi cisternae nor sorting functions, but may represent an evolutionary early form of the Golgi-like maturation compartment. Because little is known about the genesis and maturation of ESVs, we used a limited proteomics approach to discover novel proteins that are specific for developing ESVs or associated peripherally with these organelles. Unexpectedly, we identified cytoplasmic and luminal factors of the ER quality control system on two-dimensional electrophoresis gels, i.e. several proteasome subunits and HSP70-BiP. We show that BiP is exported to ESVs and retrieved via its C-terminal KDEL signal from ESVs. In contrast, cytoplasmic proteasome complexes undergo a developmentally regulated re-localization to ESVs during encystation. This suggests that maturation of bulk exported cyst wall material in the Golgi-like ESVs involves both continuous activity of ER-associated quality control mechanisms and retrograde Golgi to ER transport.

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Section: Esv Morphology Is Determined By Cargosupporting

confidence: 53%

mentioning

confidence: 59%

Organelle Proteomics Reveals Cargo Maturation Mechanisms Associated with Golgi-like Encystation Vesicles in the Early-diverged Protozoan Giardia lamblia

Štefanić

Palm

Svärd

et al. 2006

Journal of Biological Chemistry

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“…Encystation-specific vesicles (ESV) are specialized secretory granules that mature during their traffic from ER to the cell surface that act as the equivalents of late Golgi structures and are also a hallmark of encystation induction. ESV arise from: a) specialized regions of the ER, a trans-Golgi equivalent (Gottig et al, 2006); b) enlarged ER cisternae (Lanfredi-Rangel et al, 2003); or c) homotypic fusion of ER-derived COPII-coated transport vesicles into "pre-Golgi" vesicles (Marti et al, 2003). The modestly increased mRNA expression levels of structural and cargo processing molecules of ESV during encystation induction (Marti et al, 2003) suggest that these structures are derived from structural templates in the ER that differentially recruit components required for sorting and cargo maturation.…”

Section: Molecular and Structural Markers Of Giardial Encystationmentioning

confidence: 99%

Encystation commitment inGiardia duodenalis: a long and winding road

Argüello-García

Ortega‐Pierres

2009

Parasite

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“…Although many advances have been made in our understanding of cyst wall formation, particularly with regard to ultrastructural aspects of the transition and to cyst wall morphology (Sheffield and Bjorvat, 1977;Luchtel et al, 1980;Buchel et al, 1987;Erlandsen et al, 1989;Hetsko et al, 1998;Lanfredi-Rangel et al, 2003;Palm et al, 2005;Chávez-Munguía et al, 2007;Midlej and Benchimol, 2009;Bittencourt-Silvestre et al, 2010;Faso and Hehl, 2011), the cytoskeletal changes underlying both encystation and excystation have received less attention. The trophozoite microtubule cytoskeleton comprises four pairs of flagella, with eight basal bodies located between the two nuclei, as well as a ventral adhesive disc (used to attach to the intestinal epithelium) and a prominent bundle of microtubules of unknown function called the median body ( Fig.…”

Section: Introductionmentioning

confidence: 99%

Nuclear Inheritance and Genetic Exchange without Meiosis in the Binucleate ParasiteGiardia intestinalis

Carpenter

Assaf

Gourguechon

et al. 2012

Journal of Cell Science

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SummaryThe protozoan parasite Giardia intestinalis (also known as Giardia lamblia) is a major waterborne pathogen. During its life cycle, Giardia alternates between the actively growing trophozoite, which has two diploid nuclei with low levels of allelic heterozygosity, and the infectious cyst, which has four nuclei and a tough outer wall. Although the formation of the cyst wall has been studied extensively, we still lack basic knowledge about many fundamental aspects of the cyst, including the sources of the four nuclei and their distribution during the transformation from cyst into trophozoite. In this study, we tracked the identities of the nuclei in the trophozoite and cyst using integrated nuclear markers and immunofluorescence staining. We demonstrate that the cyst is formed from a single trophozoite by a mitotic division without cytokinesis and not by the fusion of two trophozoites. During excystation, the cell completes cytokinesis to form two daughter trophozoites. The non-identical nuclear pairs derived from the parent trophozoite remain associated in the cyst and are distributed to daughter cells during excystation as pairs. Thus, nuclear sorting (such that each daughter cell receives a pair of identical nuclei) does not appear to be a mechanism by which Giardia reduces heterozygosity between its nuclei. Rather, we show that the cyst nuclei exchange chromosomal genetic material, perhaps as a way to reduce heterozygosity in the absence of meiosis and sex, which have not been described in Giardia. These results shed light on fundamental aspects of the Giardia life cycle and have implications for our understanding of the population genetics and cell biology of this binucleate parasite.

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Fine structure of the biogenesis of Giardia lamblia encystation secretory vesicles

Cited by 44 publications

References 46 publications

Organelle Proteomics Reveals Cargo Maturation Mechanisms Associated with Golgi-like Encystation Vesicles in the Early-diverged Protozoan Giardia lamblia

Organelle Proteomics Reveals Cargo Maturation Mechanisms Associated with Golgi-like Encystation Vesicles in the Early-diverged Protozoan Giardia lamblia

Encystation commitment inGiardia duodenalis: a long and winding road

Nuclear Inheritance and Genetic Exchange without Meiosis in the Binucleate ParasiteGiardia intestinalis

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