34 results on '"Carmen Faso"'
Search Results
2. Nourseothricin as a novel drug for selection of transgenic Giardia lamblia
- Author
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Corina D. Wirdnam, Dawid Warmus, and Carmen Faso
- Subjects
Antibiotic ,Resistance ,Selection marker ,Giardia lamblia ,Transgenesis ,Transfection ,Infectious and parasitic diseases ,RC109-216 - Abstract
Functional gene and protein characterizations in parasitic protists are often limited by their genetic tractability. Despite the development of CRISPR-Cas9-derived or inspired approaches for a handful of protist parasites, the overall genetic tractability of these organisms remains limited. The intestinal parasite Giardia lamblia is one such species, with the added challenge of a paucity of reliable selection markers.To address this limitation, we tested the feasibility of using Nourseothricin as an effective selection agent in Giardia. Here, we report that axenically-grown WB Giardia cells are sensitive to Nourseothricin and that engineering expression of the streptothricin acetyltransferase (SAT-1) gene from Streptomyces rochei in transgenic parasites confers resistance to this antibiotic. Furthermore, we determine that SAT-1-expressing parasites are cross-resistant neither to Neomycin nor Puromycin, which are widely used to select for transgenic parasites. Consequently, we show that Nourseothricin can be used in sequential combination with both Neomycin and Puromycin to select for dual transfection events.This work increases the number of reliable selection agents and markers for Giardia genetic manipulation, expanding the limited molecular toolbox for this species of global medical importance.
- Published
- 2024
- Full Text
- View/download PDF
3. A core UPS molecular complement implicates unique endocytic compartments at the parasite–host interface in Giardia lamblia
- Author
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Erina A. Balmer, Corina D. Wirdnam, and Carmen Faso
- Subjects
Giardia lamblia ,virulence ,unconventional protein secretion ,interactome ,peripheral endocytic compartments ,Infectious and parasitic diseases ,RC109-216 - Abstract
ABSTRACTUnconventional protein secretion (UPS) plays important roles in cell physiology. In contrast to canonical secretory routes, UPS does not generally require secretory signal sequences and often bypasses secretory compartments such as the ER and the Golgi apparatus. Giardia lamblia is a protist parasite with reduced subcellular complexity which releases several proteins, some of them virulence factors, without canonical secretory signals. This implicates UPS at the parasite–host interface. No dedicated machinery nor mechanism(s) for UPS in Giardia are currently known, although speculations on the involvement of endocytic organelles called PV/PECs, have been put forth. To begin to address the question of whether PV/PECs are implicated in virulence-associated UPS and to define the composition of molecular machinery involved in protein release, we employed affinity purification and mass spectrometry, coupled to microscopy-based subcellular localization and signal correlation quantification to investigate the interactomes of 11 reported unconventionally secreted proteins, all predicted to be cytosolic. A subset of these are associated with PV/PECs. Extended and validated interactomes point to a core PV/PECs-associated UPS machinery, which includes uncharacterized and Giardia-specific coiled-coil proteins and NEK kinases. Finally, a subset of the alpha-giardin protein family was enriched in all PV/PECs-associated protein interactomes, highlighting a previously unappreciated role for these proteins at PV/PECs and in UPS. Taken together, our results provide the first characterization of a virulence-associated UPS protein complex in Giardia lamblia at PV/PECs, suggesting a novel link between these primarily endocytic and feeding organelles and UPS at the parasite–host interface.
- Published
- 2023
- Full Text
- View/download PDF
4. Combined nanometric and phylogenetic analysis of unique endocytic compartments in Giardia lamblia sheds light on the evolution of endocytosis in Metamonada
- Author
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Rui Santos, Ásgeir Ástvaldsson, Shweta V. Pipaliya, Jon Paulin Zumthor, Joel B. Dacks, Staffan Svärd, Adrian B. Hehl, and Carmen Faso
- Subjects
Endocytosis ,Super-resolution microscopy (SRM) ,Volumetric electron microscopy ,Peripheral endocytic compartments (PECs) ,Convergent evolution ,Metamonada ,Biology (General) ,QH301-705.5 - Abstract
Abstract Background Giardia lamblia, a parasitic protist of the Metamonada supergroup, has evolved one of the most diverged endocytic compartment systems investigated so far. Peripheral endocytic compartments, currently known as peripheral vesicles or vacuoles (PVs), perform bulk uptake of fluid phase material which is then digested and sorted either to the cell cytosol or back to the extracellular space. Results Here, we present a quantitative morphological characterization of these organelles using volumetric electron microscopy and super-resolution microscopy (SRM). We defined a morphological classification for the heterogenous population of PVs and performed a comparative analysis of PVs and endosome-like organelles in representatives of phylogenetically related taxa, Spironucleus spp. and Tritrichomonas foetus. To investigate the as-yet insufficiently understood connection between PVs and clathrin assemblies in G. lamblia, we further performed an in-depth search for two key elements of the endocytic machinery, clathrin heavy chain (CHC) and clathrin light chain (CLC), across different lineages in Metamonada. Our data point to the loss of a bona fide CLC in the last Fornicata common ancestor (LFCA) with the emergence of a protein analogous to CLC (GlACLC) in the Giardia genus. Finally, the location of clathrin in the various compartments was quantified. Conclusions Taken together, this provides the first comprehensive nanometric view of Giardia’s endocytic system architecture and sheds light on the evolution of GlACLC analogues in the Fornicata supergroup and, specific to Giardia, as a possible adaptation to the formation and maintenance of stable clathrin assemblies at PVs.
- Published
- 2022
- Full Text
- View/download PDF
5. Unexpected organellar locations of ESCRT machinery in Giardia intestinalis and complex evolutionary dynamics spanning the transition to parasitism in the lineage Fornicata
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Shweta V. Pipaliya, Rui Santos, Dayana Salas-Leiva, Erina A. Balmer, Corina D. Wirdnam, Andrew J. Roger, Adrian B. Hehl, Carmen Faso, and Joel B. Dacks
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ESCRT ,PV ,Giardia ,Evolutionary Cell Biology ,Endomembrane ,Parasitism ,Biology (General) ,QH301-705.5 - Abstract
Abstract Background Comparing a parasitic lineage to its free-living relatives is a powerful way to understand how that evolutionary transition to parasitism occurred. Giardia intestinalis (Fornicata) is a leading cause of gastrointestinal disease world-wide and is famous for its unusual complement of cellular compartments, such as having peripheral vacuoles instead of typical endosomal compartments. Endocytosis plays an important role in Giardia’s pathogenesis. Endosomal sorting complexes required for transport (ESCRT) are membrane-deforming proteins associated with the late endosome/multivesicular body (MVB). MVBs are ill-defined in G. intestinalis, and roles for identified ESCRT-related proteins are not fully understood in the context of its unique endocytic system. Furthermore, components thought to be required for full ESCRT functionality have not yet been documented in this species. Results We used genomic and transcriptomic data from several Fornicata species to clarify the evolutionary genome streamlining observed in Giardia, as well as to detect any divergent orthologs of the Fornicata ESCRT subunits. We observed differences in the ESCRT machinery complement between Giardia strains. Microscopy-based investigations of key components of ESCRT machinery such as GiVPS36 and GiVPS25 link them to peripheral vacuoles, highlighting these organelles as simplified MVB equivalents. Unexpectedly, we show ESCRT components associated with the endoplasmic reticulum and, for the first time, mitosomes. Finally, we identified the rare ESCRT component CHMP7 in several fornicate representatives, including Giardia and show that contrary to current understanding, CHMP7 evolved from a gene fusion of VPS25 and SNF7 domains, prior to the last eukaryotic common ancestor, over 1.5 billion years ago. Conclusions Our findings show that ESCRT machinery in G. intestinalis is far more varied and complete than previously thought, associates to multiple cellular locations, and presents changes in ESCRT complement which pre-date adoption of a parasitic lifestyle.
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- 2021
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6. Editorial: The Cell Biology of Protist Parasite-Host Interfaces
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Carmen Faso and Adrian B. Hehl
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parasite-host interactions ,protist ,cell-invasion ,protein-trafficking ,immune-evasion strategies ,parasite nutrition ,Biology (General) ,QH301-705.5 - Published
- 2022
- Full Text
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7. The Road Less Traveled? Unconventional Protein Secretion at Parasite–Host Interfaces
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Erina A. Balmer and Carmen Faso
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unconventional secretion ,protist parasites ,host–pathogen interface ,moonlighting ,glycolysis ,Biology (General) ,QH301-705.5 - Abstract
Protein secretion in eukaryotic cells is a well-studied process, which has been known for decades and is dealt with by any standard cell biology textbook. However, over the past 20 years, several studies led to the realization that protein secretion as a process might not be as uniform among different cargos as once thought. While in classic canonical secretion proteins carry a signal sequence, the secretory or surface proteome of several organisms demonstrated a lack of such signals in several secreted proteins. Other proteins were found to indeed carry a leader sequence, but simply circumvent the Golgi apparatus, which in canonical secretion is generally responsible for the modification and sorting of secretory proteins after their passage through the endoplasmic reticulum (ER). These alternative mechanisms of protein translocation to, or across, the plasma membrane were collectively termed “unconventional protein secretion” (UPS). To date, many research groups have studied UPS in their respective model organism of choice, with surprising reports on the proportion of unconventionally secreted proteins and their crucial roles for the cell and survival of the organism. Involved in processes such as immune responses and cell proliferation, and including far more different cargo proteins in different organisms than anyone had expected, unconventional secretion does not seem so unconventional after all. Alongside mammalian cells, much work on this topic has been done on protist parasites, including genera Leishmania, Trypanosoma, Plasmodium, Trichomonas, Giardia, and Entamoeba. Studies on protein secretion have mainly focused on parasite-derived virulence factors as a main source of pathogenicity for hosts. Given their need to secrete a variety of substrates, which may not be compatible with canonical secretion pathways, the study of mechanisms for alternative secretion pathways is particularly interesting in protist parasites. In this review, we provide an overview on the current status of knowledge on UPS in parasitic protists preceded by a brief overview of UPS in the mammalian cell model with a focus on IL-1β and FGF-2 as paradigmatic UPS substrates.
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- 2021
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8. Phosphoinositide-binding proteins mark, shape and functionally modulate highly-diverged endocytic compartments in the parasitic protist Giardia lamblia.
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Lenka Cernikova, Carmen Faso, and Adrian B Hehl
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Immunologic diseases. Allergy ,RC581-607 ,Biology (General) ,QH301-705.5 - Abstract
Phosphorylated derivatives of phosphatidylinositol (PIPs) are key membrane lipid residues involved in clathrin-mediated endocytosis (CME). CME relies on PIP species PI(4,5)P2 to mark endocytic sites at the plasma membrane (PM) associated to clathrin-coated vesicle (CCV) formation. The highly diverged parasitic protist Giardia lamblia presents disordered and static clathrin assemblies at PM invaginations, contacting specialized endocytic organelles called peripheral vacuoles (PVs). The role for clathrin assemblies in fluid phase uptake and their link to internal membranes via PIP-binding adaptors is unknown. Here we provide evidence for a robust link between clathrin assemblies and fluid-phase uptake in G. lamblia mediated by proteins carrying predicted PX, FYVE and NECAP1 PIP-binding modules. We show that chemical and genetic perturbation of PIP-residue binding and turnover elicits novel uptake and organelle-morphology phenotypes. A combination of co-immunoprecipitation and in silico analysis techniques expands the initial PIP-binding network with addition of new members. Our data indicate that, despite the partial conservation of lipid markers and protein cohorts known to play important roles in dynamic endocytic events in well-characterized model systems, the Giardia lineage presents a strikingly divergent clathrin-centered network. This includes several PIP-binding modules, often associated to domains of currently unknown function that shape and modulate fluid-phase uptake at PVs.
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- 2020
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9. Cyst-Wall-Protein-1 is fundamental for Golgi-like organelle neogenesis and cyst-wall biosynthesis in Giardia lamblia
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Jacqueline A. Ebneter, Sally D. Heusser, Elisabeth M. Schraner, Adrian B. Hehl, and Carmen Faso
- Subjects
Science - Abstract
Giardia lamblia is a human protozoan parasite with two diploid nuclei, which makes complete knock-out of a gene of interest challenging. Here the authors use a Cre/loxP-based approach to knock-out cyst-wall protein 1 (cwp1) and show that CWP1 is essential for cyst-wall biosynthesis.
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- 2016
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10. Five facts about Giardia lamblia.
- Author
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Lenka Cernikova, Carmen Faso, and Adrian B Hehl
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Immunologic diseases. Allergy ,RC581-607 ,Biology (General) ,QH301-705.5 - Published
- 2018
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11. An Interactome-Centered Protein Discovery Approach Reveals Novel Components Involved in Mitosome Function and Homeostasis in Giardia lamblia.
- Author
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Samuel Rout, Jon Paulin Zumthor, Elisabeth M Schraner, Carmen Faso, and Adrian B Hehl
- Subjects
Immunologic diseases. Allergy ,RC581-607 ,Biology (General) ,QH301-705.5 - Abstract
Protozoan parasites of the genus Giardia are highly prevalent globally, and infect a wide range of vertebrate hosts including humans, with proliferation and pathology restricted to the small intestine. This narrow ecological specialization entailed extensive structural and functional adaptations during host-parasite co-evolution. An example is the streamlined mitosomal proteome with iron-sulphur protein maturation as the only biochemical pathway clearly associated with this organelle. Here, we applied techniques in microscopy and protein biochemistry to investigate the mitosomal membrane proteome in association to mitosome homeostasis. Live cell imaging revealed a highly immobilized array of 30-40 physically distinct mitosome organelles in trophozoites. We provide direct evidence for the single giardial dynamin-related protein as a contributor to mitosomal morphogenesis and homeostasis. To overcome inherent limitations that have hitherto severely hampered the characterization of these unique organelles we applied a novel interaction-based proteome discovery strategy using forward and reverse protein co-immunoprecipitation. This allowed generation of organelle proteome data strictly in a protein-protein interaction context. We built an initial Tom40-centered outer membrane interactome by co-immunoprecipitation experiments, identifying small GTPases, factors with dual mitosome and endoplasmic reticulum (ER) distribution, as well as novel matrix proteins. Through iterative expansion of this protein-protein interaction network, we were able to i) significantly extend this interaction-based mitosomal proteome to include other membrane-associated proteins with possible roles in mitosome morphogenesis and connection to other subcellular compartments, and ii) identify novel matrix proteins which may shed light on mitosome-associated metabolic functions other than Fe-S cluster biogenesis. Functional analysis also revealed conceptual conservation of protein translocation despite the massive divergence and reduction of protein import machinery in Giardia mitosomes.
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- 2016
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12. Static Clathrin Assemblies at the Peripheral Vacuole-Plasma Membrane Interface of the Parasitic Protozoan Giardia lamblia.
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Jon Paulin Zumthor, Lenka Cernikova, Samuel Rout, Andres Kaech, Carmen Faso, and Adrian B Hehl
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Immunologic diseases. Allergy ,RC581-607 ,Biology (General) ,QH301-705.5 - Abstract
Giardia lamblia is a parasitic protozoan that infects a wide range of vertebrate hosts including humans. Trophozoites are non-invasive but associate tightly with the enterocyte surface of the small intestine. This narrow ecological specialization entailed extensive morphological and functional adaptations during host-parasite co-evolution, including a distinctly polarized array of endocytic organelles termed peripheral vacuoles (PVs), which are confined to the dorsal cortical region exposed to the gut lumen and are in close proximity to the plasma membrane (PM). Here, we investigated the molecular consequences of these adaptations on the Giardia endocytic machinery and membrane coat complexes. Despite the absence of canonical clathrin coated vesicles in electron microscopy, Giardia possesses conserved PV-associated clathrin heavy chain (GlCHC), dynamin-related protein (GlDRP), and assembly polypeptide complex 2 (AP2) subunits, suggesting a novel function for GlCHC and its adaptors. We found that, in contrast to GFP-tagged AP2 subunits and DRP, CHC::GFP reporters have no detectable turnover in living cells, indicating fundamental differences in recruitment to the membrane and disassembly compared to previously characterized clathrin coats. Histochemical localization in electron tomography showed that these long-lived GlCHC assemblies localized at distinctive approximations between the plasma and PV membrane. A detailed protein interactome of GlCHC revealed all of the conserved factors in addition to novel or highly diverged proteins, including a putative clathrin light chain and lipid-binding proteins. Taken together, our data provide strong evidence for giardial CHC as a component of highly stable assemblies at PV-PM junctions that likely have a central role in organizing continuities between the PM and PV membranes for controlled sampling of the fluid environment. This suggests a novel function for CHC in Giardia and the extent of molecular remodeling of endocytosis in this species.
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- 2016
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13. The proteome landscape of Giardia lamblia encystation.
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Carmen Faso, Sylvain Bischof, and Adrian B Hehl
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Medicine ,Science - Abstract
Giardia lamblia is an intestinal protozoan parasite required to survive in the environment in order to be transmitted to a new host. To ensure parasite survival, flagellated trophozoites colonizing the small intestine differentiate into non-motile environmentally-resistant cysts which are then shed in the environment. This cell differentiation process called encystation is characterized by significant morphological remodeling which includes secretion of large amounts of cyst wall material. Although much is known about the transcriptional regulation of encystation and the synthesis and trafficking of cyst wall material, the investigation of global changes in protein content and abundance during G. lamblia encystation is still unaddressed. In this study, we report on the quantitative analysis of the G. lamblia proteome during encystation using tandem mass spectrometry. Quantification of more than 1000 proteins revealed major changes in protein abundance in early, mid and late encystation, notably in constitutive secretory protein trafficking. Early stages of encystation were marked by a striking decrease of endoplasmic reticulum-targeted variant-specific surface proteins and significant increases in cytoskeleton regulatory components, NEK protein kinases and proteins involved in protein folding and glycolysis. This was in stark contrast to cells in the later stages of encystation which presented a surprisingly similar proteome composition to non-encysting trophozoites. Altogether these data constitute the first quantitative atlas of the Giardia proteome covering the whole process of encystation and point towards an important role for post-transcriptional control of gene expression in Giardia differentiation. Furthermore, our data provide a valuable resource for the community-based annotation effort of the G. lamblia genome, where almost 70% of all predicted gene models remains "hypothetical".
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- 2013
- Full Text
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14. A core UPS molecular complement implicates unique endocytic compartments at the parasite-host interface in Giardia lamblia
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Carmen Faso, Corina Wirdnam, and Erina Balmer
- Subjects
Microbiology (medical) ,Infectious Diseases ,Immunology ,Parasitology ,Microbiology - Abstract
Unconventional protein secretion (UPS) plays important roles in processes for the survival of the cell and whole organisms. In contrast to canonical secretory routes, UPS does not generally require secretory signal sequences and often bypasses secretory compartments such as the ER and the Golgi apparatus.Giardia lamblia is a protozoan parasite of global medical importance and reduced subcellular complexity known to release several proteins, some of them virulence factors, without canonical secretory signals, thus implicating UPS at the parasite-host interface. No dedicated machinery nor mechanism(s) for UPS in Giardia are currently known, although speculations on unique endocytic Giardia compartments called PV/PECs have been put forth.To begin to address the question of whether PV/PECs are implicated in virulence-associated UPS and to define the composition of molecular machinery involved in release of confirmed and putative virulence factors, in this study we employed affinity purification and mass spectrometry coupled to microscopy-based subcellular localization and signal correlation quantification techniques to investigate protein complexes of eleven reported unconventionally-secreted putative and confirmed virulence factors, all predicted to be cytosolic. A subset of selected putative and confirmed virulence factors, along with their interaction partners, unequivocally associate to the surface of PV/PECs. Extended and validated interactomes point to a core PV/PECs-associated UPS machinery, which includes uncharacterized and Giardia-specific coiled-coil proteins and NEK kinases. Finally, a specific subset of the alpha-giardin protein family was invariably found enriched in all PV/PECs-associated protein interactomes, highlighting a previously unappreciated role for these proteins at PV/PECs and in UPS.Taken together, our results provide the first characterization of a virulence-associated UPS protein complex in Giardia lamblia at PVs/PECs, suggesting a novel link between these primarily endocytic and feeding organelles and UPS at the parasite-host interface.
- Published
- 2022
15. Combined nanometric and phylogenetic analysis of unique endocytic compartments in Giardia lamblia sheds light on the evolution of endocytosis in Fornicata
- Author
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Rui Santos, Ásgeir Ástvaldsson, Shweta V. Pipaliya, Jon Paulin Zumthor, Joel B. Dacks, Staffan Svärd, Adrian B. Hehl, and Carmen Faso
- Abstract
Giardia lamblia, a parasitic protist of the metamonada supergroup, has evolved one of the most diverged endocytic compartment systems investigated so far. Peripheral endocytic compartments, currently known as peripheral vesicles or vacuoles (PVs), perform bulk uptake of fluid phase material which is then digested and sorted either to the cell cytosol or back to the extracellular space. Here, we present a quantitative morphological characterization of these organelles using volumetric electron microscopy and super-resolution microscopy (SRM). We defined a morphological classification for the heterogenous population of PVs and performed a comparative analysis of PVs and endosome-like organelles in representatives of phylogenetically-related taxa, Spironucleus spp. and Tritrichomonas foetus. To investigate the as-yet insufficiently understood connection between PVs and clathrin assemblies in G. lamblia, we further performed an in-depth search for two key elements of the endocytic machinery, clathrin heavy chain (CHC) and clathrin light chain (CLC) across different lineages in Metamonada. Our data point to the loss of a bona fide CLC in the last Fornicata common ancestor (LFCA) with the emergence of a protein analogous to CLC (GlACLC) in the Giardia genus. Taken together, this provides the first comprehensive nanometric view of Giardia’s endocytic system architecture and sheds light on the evolution of GLACLC analogues in the Fornicata supergroup and, specific to Giardia, as a possible adaptation to the formation and maintenance of stable clathrin assemblies at PVs.
- Published
- 2022
16. A cytonaut's guide to protein trafficking in Giardia lamblia
- Author
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Carmen, Faso and Adrian B, Hehl
- Subjects
Giardiasis ,Protein Transport ,Protozoan Proteins ,Giardia lamblia - Abstract
Over the past years, the subcellular organization of the Excavata member Giardia lamblia (syn. duodenalis, intestinalis) has been investigated in considerable detail. There are several reasons for this endeavour which go beyond this parasite's medical importance and are mostly concerned with its reduced subcellular complexity and debated evolutionary status. One may say that simplification has emerged as a paradigm for the evolution of Giardia's subcellular architecture. However, a complete appreciation of the evolutionary and ecological significance of this phenomenon is far from complete. In this chapter, we present and discuss the most recent data on the main trafficking pathways in G. lamblia which include endo- and exo-cytosis, organellar import and function. We provide perspectives on open questions concerning organelle replication and inheritance and include a technical outlook on methods and approaches to genetic manipulations in G. lamblia. A better understanding of G. lamblia subcellular organization at the morphological and molecular level complements any effort aimed at elucidating this parasitic species' evolutionary status and could provide us with the basis for novel strategies to interfere with parasite transmission and/or pathogenesis.
- Published
- 2019
17. A cytonaut's guide to protein trafficking in Giardia lamblia
- Author
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Adrian B. Hehl, Carmen Faso, University of Zurich, Ortega-Pierres, Guadalupe, and Hehl, Adrian B
- Subjects
10078 Institute of Parasitology ,0303 health sciences ,2405 Parasitology ,Mitosome ,610 Medicine & health ,Biology ,medicine.disease_cause ,030308 mycology & parasitology ,03 medical and health sciences ,Molecular level ,Evolutionary biology ,600 Technology ,parasitic diseases ,Ecological significance ,medicine ,Giardia lamblia ,570 Life sciences ,biology ,Parasite transmission ,Protein trafficking ,Function (biology) - Abstract
Over the past years, the subcellular organization of the Excavata member Giardia lamblia (syn. duodenalis, intestinalis) has been investigated in considerable detail. There are several reasons for this endeavour which go beyond this parasite's medical importance and are mostly concerned with its reduced subcellular complexity and debated evolutionary status. One may say that simplification has emerged as a paradigm for the evolution of Giardia's subcellular architecture. However, a complete appreciation of the evolutionary and ecological significance of this phenomenon is far from complete. In this chapter, we present and discuss the most recent data on the main trafficking pathways in G. lamblia which include endo- and exo-cytosis, organellar import and function. We provide perspectives on open questions concerning organelle replication and inheritance and include a technical outlook on methods and approaches to genetic manipulations in G. lamblia. A better understanding of G. lamblia subcellular organization at the morphological and molecular level complements any effort aimed at elucidating this parasitic species' evolutionary status and could provide us with the basis for novel strategies to interfere with parasite transmission and/or pathogenesis.
- Published
- 2019
18. Roles of Phosphoinositides and Their binding Proteins in Parasitic Protozoa
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Adrian B. Hehl, Carmen Faso, and Lenka Černíková
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0301 basic medicine ,030231 tropical medicine ,Cell ,Biology ,Trypanosoma brucei ,medicine.disease_cause ,Endocytosis ,Phosphatidylinositols ,03 medical and health sciences ,Entamoeba histolytica ,0302 clinical medicine ,parasitic diseases ,Organelle ,medicine ,Autophagy ,Giardia lamblia ,fungi ,biology.organism_classification ,Cell biology ,Protein Transport ,030104 developmental biology ,Infectious Diseases ,medicine.anatomical_structure ,Protozoa ,lipids (amino acids, peptides, and proteins) ,Parasitology ,Signal transduction ,Carrier Proteins ,Apicomplexa ,Signal Transduction - Abstract
Phosphoinositides (or phosphatidylinositol phosphates, PIPs) are low-abundance membrane phospholipids that act, in conjunction with their binding partners, as important constitutive signals defining biochemical organelle identity as well as membrane trafficking and signal transduction at eukaryotic cellular membranes. In this review, we present roles for PIP residues and PIP-binding proteins in endocytosis and autophagy in protist parasites such as Trypanosoma brucei, Toxoplasma gondii, Plasmodium falciparum, Entamoeba histolytica, and Giardia lamblia. Molecular parasitologists with an interest in comparative cell and molecular biology of membrane trafficking in protist lineages beyond the phylum Apicomplexa, along with cell and molecular biologists generally interested in the diversification of membrane trafficking in eukaryotes, will hopefully find this review to be a useful resource.
- Published
- 2019
19. Inactivation of TGFβ receptor II signalling in pancreatic epithelial cells promotes acinar cell proliferation, acinar-to-ductal metaplasia and fibrosis during pancreatitis
- Author
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Anja Zabel, Rolf Graf, Marta Bombardo, Enrica Saponara, Kamile Grabliauskaite, Theresia Reding, Carmen Faso, Gitta Maria Seleznik, Ermanno Malagola, and Sabrina Sonda
- Subjects
0301 basic medicine ,Acinar cell proliferation ,Pathology ,medicine.medical_specialty ,Biology ,medicine.disease ,Pathology and Forensic Medicine ,03 medical and health sciences ,030104 developmental biology ,medicine.anatomical_structure ,Pancreatic cancer ,Cancer research ,medicine ,Acinar cell ,Hepatic stellate cell ,Pancreatitis ,Pancreas ,Ceruletide ,Transforming growth factor - Abstract
Determining signalling pathways that regulate pancreatic regeneration following pancreatitis is critical for implementing therapeutic interventions. In this study we elucidated the molecular mechanisms underlying the effects of transforming growth factor-β (TGFβ) in pancreatic epithelial cells during tissue regeneration. To this end, we conditionally inactivated TGFβ receptor II (TGFβ-RII) using a Cre-LoxP system under the control of pancreas transcription factor 1a (PTF1a) promoter, specific for the pancreatic epithelium, and evaluated the molecular and cellular changes in a mouse model of cerulein-induced pancreatitis. We show that TGFβ-RII signalling does not mediate the initial acinar cell damage observed at the onset of pancreatitis. However, TGFβ-RII signalling not only restricts acinar cell replication during the regenerative phase of the disease but also limits ADM formation in vivo and in vitro in a cell-autonomous manner. Analyses of molecular mechanisms underlying the observed phenotype revealed that TGFβ-RII signalling stimulates the expression of cyclin-dependent kinase inhibitors and intersects with the EGFR signalling axis. Finally, TGFβ-RII ablation in epithelial cells resulted in increased infiltration of inflammatory cells in the early phases of pancreatitis and increased activation of pancreatic stellate cells in the later stages of pancreatitis, thus highlighting a TGFβ-based crosstalk between epithelial and stromal cells regulating the development of pancreatic inflammation and fibrosis. Collectively, our data not only contribute to clarifying the cellular processes governing pancreatic tissue regeneration, but also emphasize the conserved role of TGFβ as a tumour suppressor, both in the regenerative process following pancreatitis and in the initial phases of pancreatic cancer.
- Published
- 2015
20. Response to Zamponi et al
- Author
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Carmen Faso, Adrian B. Hehl, University of Zurich, and Hehl, Adrian B
- Subjects
0301 basic medicine ,10078 Institute of Parasitology ,biology ,2405 Parasitology ,Giardia ,610 Medicine & health ,2725 Infectious Diseases ,medicine.disease_cause ,Endocytosis ,biology.organism_classification ,Virology ,Clathrin ,03 medical and health sciences ,fluids and secretions ,030104 developmental biology ,Infectious Diseases ,600 Technology ,parasitic diseases ,medicine ,biology.protein ,Giardia lamblia ,570 Life sciences ,Parasitology - Abstract
In their Spotlight article titled ‘Endocytosis in Giardia: evidence of absence’ recently published in Trends in Parasitology [1], Zamponi and colleagues comment on our recent article ‘Static clathrin assemblies at the peripheral vacuole–plasma membrane interface of the parasitic protozoan Giardia lamblia’, published in the July issue of PLoS Pathogens this year [2]. We would like to alert the readership to representations of some aspects of our data and conclusions in their opinion piece with which we disagree.
- Published
- 2017
- Full Text
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21. Export of cyst wall material and Golgi organelle neogenesis inGiardia lambliadepend on endoplasmic reticulum exit sites
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Christian Konrad, Carmen Faso, Adrian B. Hehl, and Elisabeth M. Schraner
- Subjects
0303 health sciences ,Endoplasmic reticulum ,030302 biochemistry & molecular biology ,Immunology ,Golgi apparatus ,Biology ,medicine.disease_cause ,biology.organism_classification ,Microbiology ,Cell biology ,03 medical and health sciences ,symbols.namesake ,Virology ,Organelle ,medicine ,symbols ,Giardia lamblia ,Eukaryote ,Organelle biogenesis ,COPII ,hormones, hormone substitutes, and hormone antagonists ,Biogenesis ,030304 developmental biology - Abstract
Giardia lamblia parasitism accounts for the majority of cases of parasitic diarrheal disease, making this flagellated eukaryote the most successful intestinal parasite worldwide. This organism has undergone secondary reduction/elimination of entire organelle systems such as mitochondria and Golgi. However, trophozoite to cyst differentiation (encystation) requires neogenesis of Golgi-like secretory organelles named encystation-specific vesicles (ESVs), which traffic, modify and partition cyst wall proteins produced exclusively during encystation. In this work we ask whether neogenesis of Golgi-related ESVs during G. lamblia differentiation, similarly to Golgi biogenesis in more complex eukaryotes, requires the maintenance of distinct COPII-associated endoplasmic reticulum (ER) subdomains in the form of ER exit sites (ERES) and whether ERES are also present in non-differentiating trophozoites. To address this question, we identified conserved COPII components in G. lamblia cells and determined their localization, quantity and dynamics at distinct ERES domains in vegetative and differentiating trophozoites. Analogous to ERES and Golgi biogenesis, these domains were closely associated to early stages of newly generated ESV. Ectopic expression of non-functional Sar1 GTPase variants caused ERES collapse and, consequently, ESV ablation, leading to impaired parasite differentiation. Thus, our data show how ERES domains remain conserved in G. lamblia despite elimination of steady-state Golgi. Furthermore, the fundamental eukaryotic principle of ERES to Golgi/Golgi-like compartment correspondence holds true in differentiating Giardia presenting streamlined machinery for secretory organelle biogenesis and protein trafficking. However, in the Golgi-less trophozoites ERES exist as stable ER subdomains, likely as the sole sorting centres for secretory traffic.
- Published
- 2012
22. An interactome-centered protein discovery approach reveals novel components involved in mitosome function and homeostasis in giardia lamblia
- Author
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Adrian B. Hehl, Carmen Faso, Samuel Rout, Elisabeth M. Schraner, Jon Paulin Zumthor, University of Zurich, and Faso, Carmen
- Subjects
Proteomics ,0301 basic medicine ,10078 Institute of Parasitology ,Proteomes ,10077 Institute of Veterinary Anatomy ,Membrane Protein Complexes ,Cell Membranes ,Protozoan Proteins ,2405 Parasitology ,Fluorescent Antibody Technique ,Mitosome ,medicine.disease_cause ,Polymerase Chain Reaction ,Biochemistry ,Interactome ,Mass Spectrometry ,600 Technology ,Homeostasis ,Protein maturation ,lcsh:QH301-705.5 ,Energy-Producing Organelles ,Protozoans ,2404 Microbiology ,Mitochondria ,Cell biology ,Proteome ,590 Animals (Zoology) ,Protein Interaction Networks ,Cellular Structures and Organelles ,Network Analysis ,Research Article ,10244 Institute of Virology ,lcsh:Immunologic diseases. Allergy ,Computer and Information Sciences ,Immunoblotting ,Immunology ,Context (language use) ,610 Medicine & health ,Bioenergetics ,Biology ,Microbiology ,Protein–protein interaction ,03 medical and health sciences ,Microscopy, Electron, Transmission ,1311 Genetics ,Virology ,Genetics ,medicine ,1312 Molecular Biology ,Immunoprecipitation ,Giardia lamblia ,Trophozoites ,Protein Interactions ,Molecular Biology ,Organelles ,Giardia Lamblia ,2403 Immunology ,Organisms, Genetically Modified ,030102 biochemistry & molecular biology ,Giardia ,Organisms ,Biology and Life Sciences ,Membrane Proteins ,Proteins ,Protein Complexes ,Cell Biology ,Outer Membrane Proteins ,Parasitic Protozoans ,030104 developmental biology ,lcsh:Biology (General) ,Protein-Protein Interactions ,2406 Virology ,570 Life sciences ,biology ,Parasitology ,lcsh:RC581-607 ,Biogenesis - Abstract
Protozoan parasites of the genus Giardia are highly prevalent globally, and infect a wide range of vertebrate hosts including humans, with proliferation and pathology restricted to the small intestine. This narrow ecological specialization entailed extensive structural and functional adaptations during host-parasite co-evolution. An example is the streamlined mitosomal proteome with iron-sulphur protein maturation as the only biochemical pathway clearly associated with this organelle. Here, we applied techniques in microscopy and protein biochemistry to investigate the mitosomal membrane proteome in association to mitosome homeostasis. Live cell imaging revealed a highly immobilized array of 30–40 physically distinct mitosome organelles in trophozoites. We provide direct evidence for the single giardial dynamin-related protein as a contributor to mitosomal morphogenesis and homeostasis. To overcome inherent limitations that have hitherto severely hampered the characterization of these unique organelles we applied a novel interaction-based proteome discovery strategy using forward and reverse protein co-immunoprecipitation. This allowed generation of organelle proteome data strictly in a protein-protein interaction context. We built an initial Tom40-centered outer membrane interactome by co-immunoprecipitation experiments, identifying small GTPases, factors with dual mitosome and endoplasmic reticulum (ER) distribution, as well as novel matrix proteins. Through iterative expansion of this protein-protein interaction network, we were able to i) significantly extend this interaction-based mitosomal proteome to include other membrane-associated proteins with possible roles in mitosome morphogenesis and connection to other subcellular compartments, and ii) identify novel matrix proteins which may shed light on mitosome-associated metabolic functions other than Fe-S cluster biogenesis. Functional analysis also revealed conceptual conservation of protein translocation despite the massive divergence and reduction of protein import machinery in Giardia mitosomes., Author Summary Organelles with endosymbiotic origin are present in virtually all extant eukaryotes and have undergone considerable remodeling during > 1 billion years of evolution. Highly diverged organelles such as mitosomes or plastids in some parasitic protozoa are the product of extensive secondary reduction. They are sufficiently unique to generate interest as targets for pharmacological intervention, in addition to providing a rich ground for evolutionary cell biologists. The so-called mitochondria-related organelles (MROs) comprise mitosomes and hydrogenosomes, with the former having lost any role in energy metabolism along with the organelle genome. The mitosomes of the intestinal pathogen Giardia lamblia are the most highly reduced MROs known and have proven difficult to investigate because of their extreme divergence and their unique biophysical properties. Here, we implemented a novel strategy aimed at systematic analysis of the organelle proteome by iterative expansion of a protein-protein interaction network. We combined serial forward and reverse co-immunoprecipitations with mass spectrometry analysis, data mining, and validation by subcellular localization and/or functional analysis to generate an interactome network centered on a giardial Tom40 homolog. This iterative ab initio proteome reconstruction provided protein-protein interaction data in addition to identifying novel organelle proteins and functions. Building on this data we generated information on organelle replication, mitosome morphogenesis and organelle dynamics in living cells.
- Published
- 2016
23. Evidence for the involvement of the Arabidopsis SEC24A in male transmission
- Author
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Michael A. Held, Yani Chen, Renata Conger, Federica Brandizzi, Luciana Renna, Carmen Faso, Silvia Fornaciari, University of Zurich, and Brandizzi, F
- Subjects
10078 Institute of Parasitology ,0106 biological sciences ,Plant Infertility ,Physiology ,Arabidopsis ,Vesicular Transport Proteins ,610 Medicine & health ,Plant Science ,medicine.disease_cause ,01 natural sciences ,03 medical and health sciences ,Species Specificity ,600 Technology ,1110 Plant Science ,medicine ,COPII ,Arabidopsis thaliana ,Gene ,030304 developmental biology ,Gametophyte ,Genetics ,0303 health sciences ,Mutation ,biology ,Arabidopsis Proteins ,Endoplasmic reticulum ,food and beverages ,1314 Physiology ,biology.organism_classification ,Research Papers ,Transport protein ,endoplasmic reticulum ,pollen ,570 Life sciences ,Germ Cells, Plant ,AtSEC24 ,protein traffic ,010606 plant biology & botany - Abstract
Eukaryotic cells use COPII-coated carriers for endoplasmic reticulum (ER)-to-Golgi protein transport. Selective cargo capture into ER-derived carriers is largely driven by the SEC24 component of the COPII coat. The Arabidopsis genome encodes three AtSEC24 genes with overlapping expression profiles but it is yet to be established whether the AtSEC24 proteins have overlapping roles in plant growth and development. Taking advantage of Arabidopsis thaliana as a model plant system for studying gene function in vivo, through reciprocal crosses, pollen characterization, and complementation tests, evidence is provided for a role for AtSEC24A in the male gametophyte. It is established that an AtSEC24A loss-of-function mutation is tolerated in the female gametophyte but that it causes defects in pollen leading to failure of male transmission of the AtSEC24A mutation. These data provide a characterization of plant SEC24 family in planta showing incompletely overlapping functions of the AtSEC24 isoforms. The results also attribute a novel role to SEC24 proteins in a multicellular model system, specifically in male fertility.
- Published
- 2011
24. Membrane trafficking and organelle biogenesis in Giardia lamblia: use it or lose it
- Author
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Carmen Faso and Adrian B. Hehl
- Subjects
Protozoan Proteins ,Mitosome ,Biology ,medicine.disease_cause ,03 medical and health sciences ,symbols.namesake ,Organelle ,medicine ,Giardia lamblia ,Protein maturation ,030304 developmental biology ,Organelles ,0303 health sciences ,Organelle Biogenesis ,Cell Membrane ,030302 biochemistry & molecular biology ,Golgi apparatus ,Transport protein ,Cell biology ,Protein Transport ,Infectious Diseases ,symbols ,570 Life sciences ,biology ,Parasitology ,Organelle biogenesis ,Biogenesis - Abstract
The secretory transport capacity of Giardia trophozoites is perfectly adapted to the changing environment in the small intestine of the host and is able to deploy essential protective surface coats as well as molecules which act on epithelia. These lumen-dwelling parasites take up nutrients by bulk endocytosis through peripheral vesicles or by receptor-mediated transport. The environmentally-resistant cyst form is quiescent but poised for activation following stomach passage. Its versatility and fidelity notwithstanding, the giardial trafficking systems appear to be the product of a general secondary reduction process geared towards minimization of all components and machineries identified to date. Since membrane transport is directly linked to organelle biogenesis and maintenance, less complexity also means loss of organelle structures and functions. A case in point is the Golgi apparatus which is missing as a steady-state organelle system. Only a few basic Golgi functions have been experimentally demonstrated in trophozoites undergoing encystation. Similarly, mitochondrial remnants have reached a terminally minimized state and appear to be functionally restricted to essential iron-sulfur protein maturation processes. Giardia's minimized organization combined with its genetic tractability provides unique opportunities to study basic principles of secretory transport in an uncluttered cellular environment. Not surprisingly, Giardia is gaining increasing attention as a model for the investigation of gene regulation, organelle biogenesis, and export of simple but highly protective cell wall biopolymers, a hallmark of all perorally transmitted protozoan and metazoan parasites.
- Published
- 2011
- Full Text
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25. Five facts about Giardia lamblia
- Author
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Carmen Faso, Lenka Černíková, Adrian B. Hehl, University of Zurich, Odom, Audrey Ragan, and Hehl, Adrian B
- Subjects
10078 Institute of Parasitology ,Giardiasis ,Protozoan Vaccines ,0301 basic medicine ,Cell Membranes ,2405 Parasitology ,Endoplasmic Reticulum ,medicine.disease_cause ,Pearls ,600 Technology ,Medicine and Health Sciences ,lcsh:QH301-705.5 ,Protozoans ,Secretory Pathway ,2404 Microbiology ,Eukaryota ,Cell Processes ,590 Animals (Zoology) ,Cellular Structures and Organelles ,Neglected Tropical Diseases ,lcsh:Immunologic diseases. Allergy ,Diarrhea ,Immunology ,610 Medicine & health ,Computational biology ,Biology ,Microbiology ,03 medical and health sciences ,1311 Genetics ,Virology ,Parasite Groups ,1312 Molecular Biology ,Parasitic Diseases ,Genetics ,medicine ,Animals ,Humans ,Giardia lamblia ,Trophozoites ,Molecular Biology ,Giardia Lamblia ,2403 Immunology ,Protozoan Infections ,Giardia ,Endoplasmic reticulum ,Organisms ,Biology and Life Sciences ,Cell Biology ,Tropical Diseases ,Parasitic Protozoans ,030104 developmental biology ,lcsh:Biology (General) ,Parasitology ,Vacuoles ,2406 Virology ,570 Life sciences ,biology ,lcsh:RC581-607 ,Parasitic Intestinal Diseases ,Extracellular Space ,Apicomplexa - Published
- 2018
26. Deciphering the Golgi Apparatus: From Imaging to Genes
- Author
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Carmen Faso, Federica Brandizzi, and Aurelia Boulaflous
- Subjects
Endosome ,Green Fluorescent Proteins ,Arabidopsis ,Golgi Apparatus ,Vacuole ,Biology ,Endoplasmic Reticulum ,Biochemistry ,symbols.namesake ,Structural Biology ,Genetics ,Molecular Biology ,Cellular compartment ,Secretory pathway ,Microscopy, Confocal ,Arabidopsis Proteins ,Vesicular-tubular cluster ,Cell Membrane ,Membrane Proteins ,Cell Biology ,COPI ,Golgi apparatus ,Cell biology ,Protein Transport ,Mutation ,symbols ,Organelle biogenesis - Abstract
The Golgi apparatus is a vital organelle in eukaryotic cells. It grabs and processes secretory materials synthesized by the endoplasmic reticulum (ER) before sorting them to their destination. The Golgi also receives materials from vacuoles/lysosomes and the plasma membrane for further recycling to other compartments within the cell (1) (Figure 1). Given the vital role of the Golgi in a cell, it is important to understand how this organelle attains and maintains its structural and functional integrity during the intense processes of membrane traffic. Despite an equally central role of the Golgi in membrane traffic in eukaryotes, the organization of this organelle has some unique features in each cell system. Therefore, the wealth of information available on the structure and activity of the Golgi in one system is not always directly transferable to others. However, certain morphological and functional aspects are common among cell systems. Therefore, studying the factors that regulate organelle biogenesis and organization of the Golgi apparatus is important in basic cell biology of eukaryotes and may also contribute to a better understanding of how different cell systems have evolved. In this study, we report on the identification of Golgi mutants in plant cells. We have developed a screen that is a promising strategy not only for the identification of genes responsible for the morphological and functional integrity of the plant Golgi but could also provide fundamental information on other multicellular systems for which the power of forward genetics cannot be exploited as easily as in Arabidopsis.
- Published
- 2008
27. The Cre/loxP system in Giardia lamblia: genetic manipulations in a binucleate tetraploid protozoan
- Author
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Carmen Faso, Petra B. Wampfler, Adrian B. Hehl, University of Zurich, and Hehl, Adrian B
- Subjects
10078 Institute of Parasitology ,Genetics, Microbial ,2405 Parasitology ,Intestinal parasite ,Gene Expression ,610 Medicine & health ,medicine.disease_cause ,Genome ,03 medical and health sciences ,600 Technology ,parasitic diseases ,medicine ,Giardia lamblia ,Bacteriophages ,Molecular Biology ,Selectable marker ,030304 developmental biology ,Genetics ,Recombination, Genetic ,0303 health sciences ,biology ,Integrases ,030306 microbiology ,Giardia ,2725 Infectious Diseases ,biology.organism_classification ,Tetraploidy ,Infectious Diseases ,570 Life sciences ,590 Animals (Zoology) ,Protozoa ,Parasitology ,Cre-Lox recombination - Abstract
The bacteriophage-derived Cre/loxP system is a valuable tool that has revolutionised genetic and cell biological research in many organisms. We implemented this system in the intestinal parasite Giardia lamblia, an evolutionarily diverged protozoan whose binucleate and tetraploid genome organisation severely limits the application of reverse genetic approaches. We show that Cre-recombinase is functionally expressed in G. lamblia and demonstrate “recycling” of selectable markers. Providing the means for more complex and versatile genetic modifications, this technique massively increases the scope of functional investigations in G. lamblia and other protozoa with similar limitations with respect to genetic manipulation.
- Published
- 2014
28. The proteome landscape of Giardia lamblia encystation
- Author
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Sylvain Bischof, Adrian B. Hehl, Carmen Faso, and University of Zurich
- Subjects
10078 Institute of Parasitology ,Proteomics ,Giardiasis ,Proteome ,Protozoan Proteins ,lcsh:Medicine ,Protozoology ,medicine.disease_cause ,Biochemistry ,Tandem Mass Spectrometry ,600 Technology ,Gene expression ,lcsh:Science ,Protein Metabolism ,Regulation of gene expression ,0303 health sciences ,Multidisciplinary ,Spectrometric Identification of Proteins ,biology ,Proteomic Databases ,030302 biochemistry & molecular biology ,Microbial Growth and Development ,Giardia ,Gene Expression Regulation, Developmental ,Cell Differentiation ,Genomics ,Cell biology ,Transport protein ,Infectious Diseases ,Carbohydrate Metabolism ,Medicine ,Research Article ,610 Medicine & health ,1100 General Agricultural and Biological Sciences ,Biosynthesis ,Microbiology ,03 medical and health sciences ,1300 General Biochemistry, Genetics and Molecular Biology ,Genome Analysis Tools ,parasitic diseases ,medicine ,Parasitic Diseases ,Giardia lamblia ,Animals ,Humans ,Secretion ,Trophozoites ,Gene Prediction ,Biology ,Microbial Pathogens ,030304 developmental biology ,Giardia Lamblia ,1000 Multidisciplinary ,lcsh:R ,Proteins ,Biological Transport ,biology.organism_classification ,Cytoskeletal Proteins ,Secretory protein ,Metabolism ,Parastic Protozoans ,570 Life sciences ,lcsh:Q ,Parasitology ,Protein Abundance ,Developmental Biology - Abstract
Giardia lamblia is an intestinal protozoan parasite required to survive in the environment in order to be transmitted to a new host. To ensure parasite survival, flagellated trophozoites colonizing the small intestine differentiate into non-motile environmentally-resistant cysts which are then shed in the environment. This cell differentiation process called encystation is characterized by significant morphological remodeling which includes secretion of large amounts of cyst wall material. Although much is known about the transcriptional regulation of encystation and the synthesis and trafficking of cyst wall material, the investigation of global changes in protein content and abundance during G. lamblia encystation is still unaddressed. In this study, we report on the quantitative analysis of the G. lamblia proteome during encystation using tandem mass spectrometry. Quantification of more than 1000 proteins revealed major changes in protein abundance in early, mid and late encystation, notably in constitutive secretory protein trafficking. Early stages of encystation were marked by a striking decrease of endoplasmic reticulum-targeted variant-specific surface proteins and significant increases in cytoskeleton regulatory components, NEK protein kinases and proteins involved in protein folding and glycolysis. This was in stark contrast to cells in the later stages of encystation which presented a surprisingly similar proteome composition to non-encysting trophozoites. Altogether these data constitute the first quantitative atlas of the Giardia proteome covering the whole process of encystation and point towards an important role for post-transcriptional control of gene expression in Giardia differentiation. Furthermore, our data provide a valuable resource for the community-based annotation effort of the G. lamblia genome, where almost 70% of all predicted gene models remains “hypothetical”., PLoS ONE, 8 (12), ISSN:1932-6203
- Published
- 2013
29. Export of cyst wall material and Golgi organelle neogenesis in Giardia lamblia depend on endoplasmic reticulum exit sites
- Author
-
Carmen, Faso, Christian, Konrad, Elisabeth M, Schraner, and Adrian B, Hehl
- Subjects
Spores, Protozoan ,Cell Differentiation ,Giardia lamblia ,Endoplasmic Reticulum - Abstract
Giardia lamblia parasitism accounts for the majority of cases of parasitic diarrheal disease, making this flagellated eukaryote the most successful intestinal parasite worldwide. This organism has undergone secondary reduction/elimination of entire organelle systems such as mitochondria and Golgi. However, trophozoite to cyst differentiation (encystation) requires neogenesis of Golgi-like secretory organelles named encystation-specific vesicles (ESVs), which traffic, modify and partition cyst wall proteins produced exclusively during encystation. In this work we ask whether neogenesis of Golgi-related ESVs during G. lamblia differentiation, similarly to Golgi biogenesis in more complex eukaryotes, requires the maintenance of distinct COPII-associated endoplasmic reticulum (ER) subdomains in the form of ER exit sites (ERES) and whether ERES are also present in non-differentiating trophozoites. To address this question, we identified conserved COPII components in G. lamblia cells and determined their localization, quantity and dynamics at distinct ERES domains in vegetative and differentiating trophozoites. Analogous to ERES and Golgi biogenesis, these domains were closely associated to early stages of newly generated ESV. Ectopic expression of non-functional Sar1 GTPase variants caused ERES collapse and, consequently, ESV ablation, leading to impaired parasite differentiation. Thus, our data show how ERES domains remain conserved in G. lamblia despite elimination of steady-state Golgi. Furthermore, the fundamental eukaryotic principle of ERES to Golgi/Golgi-like compartment correspondence holds true in differentiating Giardia presenting streamlined machinery for secretory organelle biogenesis and protein trafficking. However, in the Golgi-less trophozoites ERES exist as stable ER subdomains, likely as the sole sorting centres for secretory traffic.
- Published
- 2012
30. A cross-sectional study of biotechnology awareness and teaching in European high schools
- Author
-
Kazim Yalcin Arga, Carmen Faso, Martin Stupak, Nadia Silva, Yech An Laizet, Klára Šimková, Paulina Leduchowska, Dominik Heinzmann, Hervé Vanderschuren, and Helen Hoerzer
- Subjects
Male ,Sociology of scientific knowledge ,Work ,Cross-sectional study ,media_common.quotation_subject ,Science ,Food, Genetically Modified ,Bioengineering ,Specific knowledge ,Environment ,Public opinion ,Science education ,Perception ,Surveys and Questionnaires ,Humans ,Applied research ,Students ,Molecular Biology ,media_common ,Schools ,business.industry ,General Medicine ,Awareness ,Biotechnology ,Europe ,Cross-Sectional Studies ,Work (electrical) ,Public Opinion ,570 Life sciences ,biology ,Female ,business - Abstract
Undoubtedly, biotechnology has a tremendous impact on our daily lives. As a result of this and in parallel to the advancement of knowledge in this field of applied research, consumer awareness of the potential benefits and risks of this technology has steadily increased, leading to a thorough investigation of the public perception of biotechnology in the past years. Indeed, it has become clear that it is in the general interest of science and especially of applied research to inform the public of its advances. A promising next step is to strengthen biotechnology communication in scholastic institutions. In this paper, we investigate the perception of biotechnology in a specific target group, namely high-school students in the 16-20-year-old age range. We conducted a questionnaire-based survey on a total of 1410 students in six European countries to investigate students' perception, concern, scientific knowledge, and awareness. Our data revealed some unexpected patterns of acceptance and concern about biotechnology. Knowledge analysis indicated that pupils lack specific knowledge about biotechnological applications and their interest in biotechnology appeared to be linked to knowledge. Analysis of specific questions about teaching practices at schools suggests that a better targeted choice in media as vehicles for information together with selected speakers could be instrumental in increasing students' interest in science and more specifically in biotechnology.
- Published
- 2009
31. The plant Golgi apparatus: last 10 years of answered and open questions
- Author
-
Aurelia Boulaflous, Carmen Faso, and Federica Brandizzi
- Subjects
Biophysics ,Golgi Apparatus ,Vacuole ,Biology ,Endoplasmic Reticulum ,Biochemistry ,Biotechnological process ,symbols.namesake ,Structural Biology ,Plant Cells ,Organelle ,Genetics ,Golgi ,Molecular Biology ,Cellular compartment ,Secretory pathway ,Plant Proteins ,food and beverages ,Cell Biology ,Cell plate ,Golgi apparatus ,Plants ,Cell biology ,symbols ,570 Life sciences ,biology ,ER export site ,Cell Division ,Golgin - Abstract
Plant Golgi bodies possess unique morphological and functional characteristics that are key to several biological and biotechnological processes, such as transport of the cell’s building blocks to energy-rich compartments, including chloroplasts, storage vacuoles and a cellulosic cell wall. During the last decade it has become apparent that the plant Golgi apparatus has features that are remarkably different from other systems. Here we summarize the most recent findings on this organelle and we highlight pressing questions that are likely to drive the next 10 years of research on the plant Golgi apparatus.
- Published
- 2009
32. A missense mutation in the arabidopsis copii coat protein sec24a induces the formation of clusters of the endoplasmic reticulum and golgi apparatus
- Author
-
Leslie Kung, RamuSubramanian Saravanan, Kentaro Tamura, Michael A. Held, Yani Chen, Lucia Marti, Chris Hawes, Carmen Faso, Starla Zemelis, Eric Hummel, Elizabeth A. Miller, and Federica Brandizzi
- Subjects
Arabidopsis ,Mutation, Missense ,Vesicular Transport Proteins ,Golgi Apparatus ,Plant Science ,Endoplasmic Reticulum ,symbols.namesake ,Microscopy, Electron, Transmission ,Gene Expression Regulation, Plant ,Arabidopsis thaliana ,COPII ,Secretory pathway ,Research Articles ,Conserved Sequence ,Golgi membrane ,Microscopy, Confocal ,biology ,Actin Cytoskeleton ,Arabidopsis Proteins ,COP-Coated Vesicles ,Intracellular Membranes ,Protein Transport ,Seedlings ,Cell Biology ,Endoplasmic reticulum ,COPI ,Golgi apparatus ,biology.organism_classification ,Cell biology ,symbols ,570 Life sciences - Abstract
How the endoplasmic reticulum (ER) and the Golgi apparatus maintain their morphological and functional identity while working in concert to ensure the production of biomolecules necessary for the cell's survival is a fundamental question in plant biology. Here, we isolated and characterized an Arabidopsis thaliana mutant that partially accumulates Golgi membrane markers and a soluble secretory marker in globular structures composed of a mass of convoluted ER tubules that maintain a connection with the bulk ER. We established that the aberrant phenotype was due to a missense recessive mutation in sec24A, one of the three Arabidopsis isoforms encoding the coat protomer complex II (COPII) protein Sec24, and that the mutation affects the distribution of this critical component at ER export sites. By contrast, total loss of sec24A function was lethal, suggesting that Arabidopsis sec24A is an essential gene. These results produce important insights into the functional diversification of plant COPII coat components and the role of these proteins in maintaining the dynamic identity of organelles of the early plant secretory pathway.
- Published
- 2009
33. Inducible expression of maize polyamine oxidase in the nucleus of MCF-7 human breast cancer cells confers sensitivity to etoposide
- Author
-
Bruno Mondovi, S Leone, Rodolfo Federico, A Antoccia, Carmen Faso, Lucia Marcocci, Paraskevi Tavladoraki, M Casadei, Pasquale Stano, Marcocci, L, Casadei, M, Faso, C, Antoccia, A, Stano, P, Leone, S, Mondovì, B, Federico, R, and Tavladoraki, Paraskevi
- Subjects
polyamines ,Clinical Biochemistry ,aminoaldehydes ,Spermine ,Cellular homeostasis ,Breast Neoplasms ,hydrogen peroxide ,Biology ,Zea mays ,Biochemistry ,etoposide ,Gene Expression Regulation, Enzymologic ,chemistry.chemical_compound ,terminal catabolism ,Cell Line, Tumor ,Humans ,Cell Proliferation ,Cell Nucleus ,Oxidoreductases Acting on CH-NH Group Donors ,Organic Chemistry ,Antineoplastic Agents, Phytogenic ,Recombinant Proteins ,human breast cancer cells ,polyamine oxidase ,Spermidine ,chemistry ,Doxycycline ,Cancer cell ,Putrescine ,Polyamine homeostasis ,Polyamine ,Polyamine oxidase - Abstract
In this study, polyamine oxidase from maize (MPAO), which is involved in the terminal catabolism of spermidine and spermine to produce an aminoaldehyde, 1,3-diaminopropane and H(2)O(2), has been conditionally expressed at high levels in the nucleus of MCF-7 human breast cancer cells, with the aim to interfere with polyamine homeostasis and cell proliferation. Recombinant MPAO expression induced accumulation of a high amount of 1,3-diaminopropane, an increase of putrescine levels and no alteration in the cellular content of spermine and spermidine. Furthermore, recombinant MPAO expression did not interfere with cell growth of MCF-7 cells under normal conditions but it did confer higher growth sensitivity to etoposide, a DNA topoisomerase II inhibitor widely used as antineoplastic drug. These data suggest polyamine oxidases as a potential tool to improve the efficiency of antiproliferative agents despite the difficulty to interfere with cellular homeostasis of spermine and spermidine.
- Published
- 2008
34. Lys300 plays a major role in the catalytic mechanism of maize polyamine oxidase
- Author
-
Carmen Faso, Rodolfo Federico, Fabio Polticelli, Paraskevi Tavladoraki, Giovanni Minervini, R Angelini, Jaswir Basran, Alessandra Cona, Nigel S. Scrutton, Polticelli, Fabio, Basran, J, Faso, C, Cona, Alessandra, Minervini, G, Angelini, R, Federico, R, SCRUTTON N., S, and Tavladoraki, Paraskevi
- Subjects
Models, Molecular ,Spermine oxidase ,Stereochemistry ,Flavin group ,catalytic mechanism ,Biochemistry ,Zea mays ,chemistry.chemical_compound ,Models ,Flavins ,Site-Directed ,spermine oxidase ,Plant Proteins ,chemistry.chemical_classification ,Flavin adenine dinucleotide ,Oxidoreductases Acting on CH-NH Group Donors ,Binding Sites ,biology ,Molecular Structure ,Lysine ,Molecular ,Hydrogen-Ion Concentration ,Flavin-Adenine Dinucleotide ,Mutagenesis, Site-Directed ,Oxidation-Reduction ,molecular dynamics ,Enzyme assay ,polyamine oxidase ,Spermidine ,Dissociation constant ,Enzyme ,chemistry ,Mutagenesis ,biology.protein ,Polyamine oxidase - Abstract
Maize polyamine oxidase (MPAO) is a flavin adenine dinucleotide (FAD)-dependent enzyme that catalyses the oxidation of spermine and spermidine at the secondary amino groups. The structure of MPAO indicates a 30-A long U-shaped tunnel that forms the catalytic site, with residues Glu62 and Glu170 located close to the enzyme-bound FAD and residue Tyr298 in close proximity to Lys300, which in turn is hydrogen-bonded to the flavin N(5) atom via a water molecule (HOH309). To provide insight into the role of these residues in the catalytic mechanism of FAD reduction, we have performed steady-state and stopped-flow studies with wild-type, Glu62Gln, Glu170Gln, Tyr298Phe, and Lys300Met MPAO enzymes. We show that the steady-state enzyme activity is governed by an ionisable group with a macroscopic pK(a) of approximately 5.8. Kinetic analysis of the Glu62Gln, Glu170Gln, and Tyr298Phe MPAO enzymes have indicated (i) only small perturbations in catalytic activity as a result of mutation and (ii) steady-state pH profiles essentially unaltered when compared to the wild-type enzyme, suggesting that these residues do not play a critical role in the reaction mechanism. These kinetic observations are consistent with computational calculations that suggest that Glu62 and Glu170 are protonated over the pH range accessible to kinetic studies. Substitution of Lys300 with Met in MPAO resulted in a 1400-fold decrease in the rate of flavin reduction and a 160-fold decrease in the equilibrium dissociation constant for the Lys300Met-spermidine complex, consistent with a major role for this residue in the mechanism of substrate oxidation. A sizable solvent isotope effect (SIE = 5) accompanies FAD reduction in the wild-type enzyme and steady-state turnover (SIE = 2.3) of MPAO, consistent with the reductive half-reaction of MPAO making a major contribution to rate limitation in steady-state turnover. Studies using the enzyme-monitored turnover method indicate that oxidized FAD is the prominent form during steady-state turnover, consistent with the reductive half-reaction being rate-limiting. Our studies indicate the importance of Lys300 and probable importance of HOH309 to the mechanism of flavin reduction in MPAO. Possible roles for Lys300 and water in the mechanism of flavin reduction are discussed.
- Published
- 2005
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