1
|
Back PS, Senthilkumar V, Choi CP, Ly AM, Snyder AK, Lau JG, Ward GE, Bradley PJ. The Toxoplasma subpellicular network is highly interconnected and defines parasite shape for efficient motility and replication. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.10.552545. [PMID: 37609316 PMCID: PMC10441382 DOI: 10.1101/2023.08.10.552545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Apicomplexan parasites possess several specialized structures to invade their host cells and replicate successfully. One of these is the inner membrane complex (IMC), a peripheral membrane-cytoskeletal system underneath the plasma membrane. It is composed of a series of flattened, membrane-bound vesicles and a cytoskeletal subpellicular network (SPN) comprised of intermediate filament-like proteins called alveolins. While the alveolin proteins are conserved throughout the Apicomplexa and the broader Alveolata, their precise functions and interactions remain poorly understood. Here, we describe the function of one of these alveolin proteins, TgIMC6. Disruption of IMC6 resulted in striking morphological defects that led to aberrant motility, invasion, and replication. Deletion analyses revealed that the alveolin domain alone is largely sufficient to restore localization and partially sufficient for function. As this highlights the importance of the IMC6 alveolin domain, we implemented unnatural amino acid photoreactive crosslinking to the alveolin domain and identified multiple binding interfaces between IMC6 and two other cytoskeletal proteins - IMC3 and ILP1. To our knowledge, this provides the first direct evidence of protein-protein interactions in the alveolin domain and supports the long-held hypothesis that the alveolin domain is responsible for filament formation. Collectively, our study features the conserved alveolin proteins as critical components that maintain the parasite's structural integrity and highlights the alveolin domain as a key mediator of SPN architecture.
Collapse
|
2
|
Abstract
Protein kinases of the protozoan parasite Toxoplasma gondii have been shown to play key roles in regulating parasite motility, invasion, replication, egress and survival within the host. The tyrosine kinase-like (TKL) kinase family of proteins are a set of poorly studied kinases that our recent studies have indicated play a critical role in Toxoplasma biology. In this study, we focused on TgTKL4, another member of the TKL family that is predicted to confer parasite fitness. Endogenous tagging of TgTKL4 identified it as a temporally oscillating kinase with dynamic localization in the parasite. Gene disruption experiments suggested that TgTKL4 is important for Toxoplasma propagation in vitro, and loss of this kinase resulted in replication and invasion defects. During parasite division, TgTKL4 expression was limited to the synthesis and mitosis-cytokinesis phases and, interestingly, loss of TgTKL4 led to defects in Toxoplasma morphology. Further analysis of the parasite cytoskeleton indicated that the subpellicular microtubules are shorter and more widely spaced in parasites lacking TgTKL4. Although loss of TgTKL4 caused only moderate changes in the gene expression profile, TgTKL4 null mutants exhibited significant changes in their global phospho-proteome, including in proteins that constitute the parasite cytoskeleton. Additionally, mice inoculated intraperitoneally with TgTKL4 knockout parasites showed increased survival rates, suggesting that TgTKL4 plays an important role in acute toxoplasmosis. Together, these findings suggest that TgTKL4 mediates a signaling pathway that regulates parasite morphology and is an important factor required for parasite fitness in vitro and in vivo. IMPORTANCE Toxoplasma gondii is a protozoan parasite that can cause life-threatening disease in mammals; hence, identifying key factors required for parasite growth and pathogenesis is important to develop novel therapeutics. In this study, we identified and characterized another member of the newly described TKL family, TgTKL4, a cell cycle-regulated kinase. By disrupting TgTKL4, we determined that this kinase is required for normal parasite growth in vitro and that loss of this kinase results in parasites with reduced competence in replication and invasion processes. Specifically, Toxoplasma parasites lacking TgTKL4 had defects in cytoskeletal arrangement, resulting in parasites with abnormal morphology. Phospho-proteome studies provided further clues that decreased phosphorylation of proteins that constitute the Toxoplasma cytoskeleton could be responsible for altered morphology in TgTKL4-deficient parasites. Additionally, loss of TgTKL4 resulted in attenuation of virulence in the animal model, suggesting that TgTKL4 is an important virulence factor. Hence, this study provides a novel insight into the importance of a TgTKL4 as a fitness-determining factor for Toxoplasma propagation in vitro and pathogenesis in vivo.
Collapse
|
3
|
Wichers JS, Wunderlich J, Heincke D, Pazicky S, Strauss J, Schmitt M, Kimmel J, Wilcke L, Scharf S, von Thien H, Burda PC, Spielmann T, Löw C, Filarsky M, Bachmann A, Gilberger TW. Identification of novel inner membrane complex and apical annuli proteins of the malaria parasite Plasmodium falciparum. Cell Microbiol 2021; 23:e13341. [PMID: 33830607 DOI: 10.1111/cmi.13341] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/29/2021] [Accepted: 04/05/2021] [Indexed: 02/06/2023]
Abstract
The inner membrane complex (IMC) is a defining feature of apicomplexan parasites, which confers stability and shape to the cell, functions as a scaffolding compartment during the formation of daughter cells and plays an important role in motility and invasion during different life cycle stages of these single-celled organisms. To explore the IMC proteome of the malaria parasite Plasmodium falciparum we applied a proximity-dependent biotin identification (BioID)-based proteomics approach, using the established IMC marker protein Photosensitized INA-Labelled protein 1 (PhIL1) as bait in asexual blood-stage parasites. Subsequent mass spectrometry-based peptide identification revealed enrichment of 12 known IMC proteins and several uncharacterized candidate proteins. We validated nine of these previously uncharacterized proteins by endogenous GFP-tagging. Six of these represent new IMC proteins, while three proteins have a distinct apical localization that most likely represents structures described as apical annuli in Toxoplasma gondii. Additionally, various Kelch13 interacting candidates were identified, suggesting an association of the Kelch13 compartment and the IMC in schizont and merozoite stages. This work extends the number of validated IMC proteins in the malaria parasite and reveals for the first time the existence of apical annuli proteins in P. falciparum. Additionally, it provides evidence for a spatial association between the Kelch13 compartment and the IMC in late blood-stage parasites.
Collapse
Affiliation(s)
- Jan Stephan Wichers
- Centre for Structural Systems Biology, Hamburg, Germany.,Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,University of Hamburg, Hamburg, Germany
| | - Juliane Wunderlich
- Centre for Structural Systems Biology, Hamburg, Germany.,European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | - Dorothee Heincke
- Centre for Structural Systems Biology, Hamburg, Germany.,Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,University of Hamburg, Hamburg, Germany
| | - Samuel Pazicky
- Centre for Structural Systems Biology, Hamburg, Germany.,European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | - Jan Strauss
- Centre for Structural Systems Biology, Hamburg, Germany.,Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,University of Hamburg, Hamburg, Germany
| | - Marius Schmitt
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Jessica Kimmel
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Louisa Wilcke
- Centre for Structural Systems Biology, Hamburg, Germany.,Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,University of Hamburg, Hamburg, Germany
| | - Sarah Scharf
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Heidrun von Thien
- Centre for Structural Systems Biology, Hamburg, Germany.,Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,University of Hamburg, Hamburg, Germany
| | - Paul-Christian Burda
- Centre for Structural Systems Biology, Hamburg, Germany.,Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,University of Hamburg, Hamburg, Germany
| | - Tobias Spielmann
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Christian Löw
- Centre for Structural Systems Biology, Hamburg, Germany.,European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | - Michael Filarsky
- Centre for Structural Systems Biology, Hamburg, Germany.,University of Hamburg, Hamburg, Germany
| | - Anna Bachmann
- Centre for Structural Systems Biology, Hamburg, Germany.,Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,University of Hamburg, Hamburg, Germany.,German Centre for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Braunschweig, Germany
| | - Tim W Gilberger
- Centre for Structural Systems Biology, Hamburg, Germany.,Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,University of Hamburg, Hamburg, Germany
| |
Collapse
|
4
|
Abstract
Apicomplexans are obligate intracellular parasites harboring three sets of unique secretory organelles termed micronemes, rhoptries, and dense granules that are dedicated to the establishment of infection in the host cell. Apicomplexans rely on the endolysosomal system to generate the secretory organelles and to ingest and digest host cell proteins. These parasites also possess a metabolically relevant secondary endosymbiotic organelle, the apicoplast, which relies on vesicular trafficking for correct incorporation of nuclear-encoded proteins into the organelle. Here, we demonstrate that the trafficking and destination of vesicles to the unique and specialized parasite compartments depend on SNARE proteins that interact with tethering factors. Specifically, all secreted proteins depend on the function of SLY1 at the Golgi. In addition to a critical role in trafficking of endocytosed host proteins, TgVps45 is implicated in the biogenesis of the inner membrane complex (alveoli) in both Toxoplasma gondii and Plasmodium falciparum, likely acting in a coordinated manner with Stx16 and Stx6. Finally, Stx12 localizes to the endosomal-like compartment and is involved in the trafficking of proteins to the apical secretory organelles rhoptries and micronemes as well as to the apicoplast.IMPORTANCE The phylum of Apicomplexa groups medically relevant parasites such as those responsible for malaria and toxoplasmosis. As members of the Alveolata superphylum, these protozoans possess specialized organelles in addition to those found in all members of the eukaryotic kingdom. Vesicular trafficking is the major route of communication between membranous organelles. Neither the molecular mechanism that allows communication between organelles nor the vesicular fusion events that underlie it are completely understood in Apicomplexa. Here, we assessed the function of SEC1/Munc18 and SNARE proteins to identify factors involved in the trafficking of vesicles between these various organelles. We show that SEC1/Munc18 in interaction with SNARE proteins allows targeting of vesicles to the inner membrane complex, prerhoptries, micronemes, apicoplast, and vacuolar compartment from the endoplasmic reticulum, Golgi apparatus, or endosomal-like compartment. These data provide an exciting look at the "ZIP code" of vesicular trafficking in apicomplexans, essential for precise organelle biogenesis, homeostasis, and inheritance.
Collapse
|
5
|
Coghlan MP, Tremp AZ, Saeed S, Vaughan CK, Dessens JT. Distinct Functional Contributions by the Conserved Domains of the Malaria Parasite Alveolin IMC1h. Front Cell Infect Microbiol 2019; 9:266. [PMID: 31428588 PMCID: PMC6689960 DOI: 10.3389/fcimb.2019.00266] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 07/08/2019] [Indexed: 12/31/2022] Open
Abstract
Invasive, motile life cycle stages (zoites) of apicomplexan parasites possess a cortical membrane skeleton composed of intermediate filaments with roles in zoite morphogenesis, tensile strength and motility. Its building blocks include a family of proteins called alveolins that are characterized by conserved "alveolin" domains composed of tandem repeat sequences. A subset of alveolins possess additional conserved domains that are structurally unrelated and the roles of which remain unclear. In this structure-function analysis we investigated the functional contributions of the "alveolin" vs. "non-alveolin" domains of IMC1h, a protein expressed in the ookinete and sporozoite life cycle stages of malaria parasites and essential for parasite transmission. Using allelic replacement in Plasmodium berghei, we show that the alveolin domain is responsible for targeting IMC1h to the membrane skeleton and, consequently, its deletion from the protein results in loss of function manifested by abnormally-shaped ookinetes and sporozoites with reduced tensile strength, motility and infectivity. Conversely, IMC1h lacking its non-alveolin conserved domain is correctly targeted and can facilitate tensile strength but not motility. Our findings support the concept that the alveolin module contains the properties for filament formation, and show for the first time that tensile strength makes an important contribution to zoite infectivity. The data furthermore provide new insight into the underlying molecular mechanisms of motility, indicating that tensile strength is mechanistically uncoupled from locomotion, and pointing to a role of the non-alveolin domain in the motility-enhancing properties of IMC1h possibly by engaging with the locomotion apparatus.
Collapse
Affiliation(s)
- Michael P Coghlan
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom.,Institute of Structural and Molecular Biology, School of Biological Sciences, Birkbeck, London, United Kingdom
| | - Annie Z Tremp
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Sadia Saeed
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Cara K Vaughan
- Institute of Structural and Molecular Biology, School of Biological Sciences, Birkbeck, London, United Kingdom
| | - Johannes T Dessens
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| |
Collapse
|
6
|
Jumani RS, Hasan MM, Stebbins EE, Donnelly L, Miller P, Klopfer C, Bessoff K, Teixeira JE, Love MS, McNamara CW, Huston CD. A suite of phenotypic assays to ensure pipeline diversity when prioritizing drug-like Cryptosporidium growth inhibitors. Nat Commun 2019; 10:1862. [PMID: 31015448 PMCID: PMC6478823 DOI: 10.1038/s41467-019-09880-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 04/01/2019] [Indexed: 01/07/2023] Open
Abstract
Cryptosporidiosis is a leading cause of life-threatening diarrhea in children, and the only currently approved drug is ineffective in malnourished children and immunocompromised people. Large-scale phenotypic screens are ongoing to identify anticryptosporidial compounds, but optimal approaches to prioritize inhibitors and establish a mechanistically diverse drug development pipeline are unknown. Here, we present a panel of medium-throughput mode of action assays that enable testing of compounds in several stages of the Cryptosporidium life cycle. Phenotypic profiles are given for thirty-nine anticryptosporidials. Using a clustering algorithm, the compounds sort by phenotypic profile into distinct groups of inhibitors that are either chemical analogs (i.e. same molecular mechanism of action (MMOA)) or known to have similar MMOA. Furthermore, compounds belonging to multiple phenotypic clusters are efficacious in a chronic mouse model of cryptosporidiosis. This suite of phenotypic assays should ensure a drug development pipeline with diverse MMOA without the need to identify underlying mechanisms.
Collapse
Affiliation(s)
- Rajiv S Jumani
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT, 05405, USA.,Cellular, Molecular and Biomedical Sciences Graduate Program, University of Vermont, Burlington, VT, 05405, USA.,Novartis Institute for Tropical Diseases, Novartis Institutes for BioMedical Research, Emeryville, CA, 94608, USA
| | - Muhammad M Hasan
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT, 05405, USA.,Cellular, Molecular and Biomedical Sciences Graduate Program, University of Vermont, Burlington, VT, 05405, USA
| | - Erin E Stebbins
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT, 05405, USA
| | - Liam Donnelly
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT, 05405, USA
| | - Peter Miller
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT, 05405, USA
| | - Connor Klopfer
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT, 05405, USA
| | - Kovi Bessoff
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT, 05405, USA.,Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, 94305-5101, USA
| | - Jose E Teixeira
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT, 05405, USA
| | - Melissa S Love
- Calibr at The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Case W McNamara
- Calibr at The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Christopher D Huston
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT, 05405, USA. .,Cellular, Molecular and Biomedical Sciences Graduate Program, University of Vermont, Burlington, VT, 05405, USA. .,Department of Microbiology and Molecular Genetics, University of Vermont Larner College of Medicine, Burlington, VT, 05405, USA.
| |
Collapse
|
7
|
Harding CR, Gow M, Kang JH, Shortt E, Manalis SR, Meissner M, Lourido S. Alveolar proteins stabilize cortical microtubules in Toxoplasma gondii. Nat Commun 2019; 10:401. [PMID: 30674885 PMCID: PMC6344517 DOI: 10.1038/s41467-019-08318-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 01/04/2019] [Indexed: 12/21/2022] Open
Abstract
Single-celled protists use elaborate cytoskeletal structures, including arrays of microtubules at the cell periphery, to maintain polarity and rigidity. The obligate intracellular parasite Toxoplasma gondii has unusually stable cortical microtubules beneath the alveoli, a network of flattened membrane vesicles that subtends the plasmalemma. However, anchoring of microtubules along alveolar membranes is not understood. Here, we show that GAPM1a, an integral membrane protein of the alveoli, plays a role in maintaining microtubule stability. Degradation of GAPM1a causes cortical microtubule disorganisation and subsequent depolymerisation. These changes in the cytoskeleton lead to parasites becoming shorter and rounder, which is accompanied by a decrease in cellular volume. Extended GAPM1a depletion leads to severe defects in division, reminiscent of the effect of disrupting other alveolar proteins. We suggest that GAPM proteins link the cortical microtubules to the alveoli and are required to maintain the shape and rigidity of apicomplexan zoites. Cortical microtubules of Toxoplasma gondii are exceptionally stable, but it isn’t known how they are anchored along membranes. Here, Harding et al. show that GAPM proteins localize to the inner membrane complex and are essential for maintaining the structural stability of parasites.
Collapse
Affiliation(s)
- Clare R Harding
- Whitehead Institute for Biomedical Research, Cambridge, 02142, MA, USA.
| | - Matthew Gow
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, G12 8TA, UK
| | - Joon Ho Kang
- Department of Physics, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA.,Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA
| | - Emily Shortt
- Whitehead Institute for Biomedical Research, Cambridge, 02142, MA, USA
| | - Scott R Manalis
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA.,Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA
| | - Markus Meissner
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, G12 8TA, UK.,Department of Veterinary Sciences, Ludwig-Maximilians-Universität, Munich, 80539, Germany
| | - Sebastian Lourido
- Whitehead Institute for Biomedical Research, Cambridge, 02142, MA, USA. .,Biology Department, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA.
| |
Collapse
|
8
|
Saini E, Zeeshan M, Brady D, Pandey R, Kaiser G, Koreny L, Kumar P, Thakur V, Tatiya S, Katris NJ, Limenitakis RS, Kaur I, Green JL, Bottrill AR, Guttery DS, Waller RF, Heussler V, Holder AA, Mohmmed A, Malhotra P, Tewari R. Photosensitized INA-Labelled protein 1 (PhIL1) is novel component of the inner membrane complex and is required for Plasmodium parasite development. Sci Rep 2017; 7:15577. [PMID: 29138437 PMCID: PMC5686188 DOI: 10.1038/s41598-017-15781-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 11/01/2017] [Indexed: 11/09/2022] Open
Abstract
Plasmodium parasites, the causative agents of malaria, possess a distinctive membranous structure of flattened alveolar vesicles supported by a proteinaceous network, and referred to as the inner membrane complex (IMC). The IMC has a role in actomyosin-mediated motility and host cell invasion. Here, we examine the location, protein interactome and function of PhIL1, an IMC-associated protein on the motile and invasive stages of both human and rodent parasites. We show that PhIL1 is located in the IMC in all three invasive (merozoite, ookinete-, and sporozoite) stages of development, as well as in the male gametocyte and locates both at the apical and basal ends of ookinete and sporozoite stages. Proteins interacting with PhIL1 were identified, showing that PhIL1 was bound to only some proteins present in the glideosome motor complex (GAP50, GAPM1–3) of both P. falciparum and P. berghei. Analysis of PhIL1 function using gene targeting approaches indicated that the protein is required for both asexual and sexual stages of development. In conclusion, we show that PhIL1 is required for development of all zoite stages of Plasmodium and it is part of a novel protein complex with an overall composition overlapping with but different to that of the glideosome.
Collapse
Affiliation(s)
- Ekta Saini
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Mohammad Zeeshan
- School of Life Sciences, University of Nottingham, Nottingham, NG72UH, UK
| | - Declan Brady
- School of Life Sciences, University of Nottingham, Nottingham, NG72UH, UK
| | - Rajan Pandey
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Gesine Kaiser
- Institute of Cell Biology, University of Bern, Bern, 3012, Switzerland
| | - Ludek Koreny
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Pradeep Kumar
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Vandana Thakur
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Shreyansh Tatiya
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Nicholas J Katris
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | | | - Inderjeet Kaur
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | | | - Andrew R Bottrill
- Protein and Nucleic Acid Chemistry Laboratory, University of Leicester, Leicester, LE2 7LX, UK
| | - David S Guttery
- Department of Cancer studies, University of Leicester, Leicester, LE2 7LX, UK
| | - Ross F Waller
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Volker Heussler
- Institute of Cell Biology, University of Bern, Bern, 3012, Switzerland
| | | | - Asif Mohmmed
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Pawan Malhotra
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India.
| | - Rita Tewari
- School of Life Sciences, University of Nottingham, Nottingham, NG72UH, UK.
| |
Collapse
|
9
|
Parkyn Schneider M, Liu B, Glock P, Suttie A, McHugh E, Andrew D, Batinovic S, Williamson N, Hanssen E, McMillan P, Hliscs M, Tilley L, Dixon MWA. Disrupting assembly of the inner membrane complex blocks Plasmodium falciparum sexual stage development. PLoS Pathog 2017; 13:e1006659. [PMID: 28985225 PMCID: PMC5646874 DOI: 10.1371/journal.ppat.1006659] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 10/18/2017] [Accepted: 09/20/2017] [Indexed: 11/18/2022] Open
Abstract
Transmission of malaria parasites relies on the formation of a specialized blood form called the gametocyte. Gametocytes of the human pathogen, Plasmodium falciparum, adopt a crescent shape. Their dramatic morphogenesis is driven by the assembly of a network of microtubules and an underpinning inner membrane complex (IMC). Using super-resolution optical and electron microscopies we define the ultrastructure of the IMC at different stages of gametocyte development. We characterize two new proteins of the gametocyte IMC, called PhIL1 and PIP1. Genetic disruption of PhIL1 or PIP1 ablates elongation and prevents formation of transmission-ready mature gametocytes. The maturation defect is accompanied by failure to form an enveloping IMC and a marked swelling of the digestive vacuole, suggesting PhIL1 and PIP1 are required for correct membrane trafficking. Using immunoprecipitation and mass spectrometry we reveal that PhIL1 interacts with known and new components of the gametocyte IMC. Transmission of the malaria parasite from humans to mosquitoes relies on the formation of the specialised blood stage gametocyte. Plasmodium falciparum gametocytes mature over about 10 days, during which time they undergo a remarkable morphological transformation, eventually adopting a characteristic crescent shape. The shape changes are thought to facilitate the mechanical sequestration of maturing gametocytes within the bone marrow and spleen, as well as the eventual release into the circulation. Failure to mature correctly leads to a failure to transmit. Despite the importance of this process, little is known about the molecular basis of elongation. In this work, we introduce 3D Electron Microscopy of P. falciparum gametocytes and use it, in a combination with super-resolution optical microscopy, to elucidate the genesis and expansion of the molecular structures that drive gametocyte elongation. We use protein interaction profiling to identify some of the proteins that help drive the shape change and employ inducible gene knockdown strategies to show that these proteins play a role in remodeling membranes, and are needed for gametocyte elongation. This work points to potential targets for the development of transmission-blocking therapies.
Collapse
Affiliation(s)
- Molly Parkyn Schneider
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Boyin Liu
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Philipp Glock
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Annika Suttie
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Emma McHugh
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Dean Andrew
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Steven Batinovic
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Nicholas Williamson
- Mass Spectrometry and Proteomics Facility, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Eric Hanssen
- Melbourne Advance Microscopy Facility, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Paul McMillan
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Victoria, Australia
- Melbourne Advance Microscopy Facility, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
- Biological Optical Microscopy Platform, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Marion Hliscs
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Leann Tilley
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Matthew W. A. Dixon
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Victoria, Australia
- * E-mail:
| |
Collapse
|
10
|
Leung JM, He Y, Zhang F, Hwang YC, Nagayasu E, Liu J, Murray JM, Hu K. Stability and function of a putative microtubule-organizing center in the human parasite Toxoplasma gondii. Mol Biol Cell 2017; 28:1361-1378. [PMID: 28331073 PMCID: PMC5426850 DOI: 10.1091/mbc.e17-01-0045] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 03/03/2017] [Accepted: 03/17/2017] [Indexed: 12/17/2022] Open
Abstract
KinesinA and APR1 maintain the stability of the apical polar ring, a putative organizing center for the 22 cortical microtubules of Toxoplasma. Parasites lacking these two proteins are defective in invasion, motility, secretion, and growth but can still make 22 cortical microtubules, suggesting that ring stability is not tightly coupled to templating. The organization of the microtubule cytoskeleton is dictated by microtubule nucleators or organizing centers. Toxoplasma gondii, an important human parasite, has an array of 22 regularly spaced cortical microtubules stemming from a hypothesized organizing center, the apical polar ring. Here we examine the functions of the apical polar ring by characterizing two of its components, KinesinA and APR1, and show that its putative role in templating can be separated from its mechanical stability. Parasites that lack both KinesinA and APR1 (ΔkinesinAΔapr1) are capable of generating 22 cortical microtubules. However, the apical polar ring is fragmented in live ΔkinesinAΔapr1 parasites and is undetectable by electron microscopy after detergent extraction. Disintegration of the apical polar ring results in the detachment of groups of microtubules from the apical end of the parasite. These structural defects are linked to a diminished ability of the parasite to move and invade host cells, as well as decreased secretion of effectors important for these processes. Together the findings demonstrate the importance of the structural integrity of the apical polar ring and the microtubule array in the Toxoplasma lytic cycle, which is responsible for massive tissue destruction in acute toxoplasmosis.
Collapse
Affiliation(s)
| | - Yudou He
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Fangliang Zhang
- Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Miami, FL 33136
| | | | - Eiji Nagayasu
- Department of Infectious Diseases, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Jun Liu
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - John M Murray
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Ke Hu
- Department of Biology, Indiana University, Bloomington, IN 47405
| |
Collapse
|
11
|
Global iTRAQ-based proteomic profiling of Toxoplasma gondii oocysts during sporulation. J Proteomics 2016; 148:12-9. [DOI: 10.1016/j.jprot.2016.07.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 06/15/2016] [Accepted: 07/11/2016] [Indexed: 12/19/2022]
|
12
|
Foe IT, Child MA, Majmudar JD, Krishnamurthy S, van der Linden WA, Ward GE, Martin BR, Bogyo M. Global Analysis of Palmitoylated Proteins in Toxoplasma gondii. Cell Host Microbe 2016; 18:501-11. [PMID: 26468752 DOI: 10.1016/j.chom.2015.09.006] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 08/25/2015] [Accepted: 09/16/2015] [Indexed: 02/01/2023]
Abstract
Post-translational modifications (PTMs) such as palmitoylation are critical for the lytic cycle of the protozoan parasite Toxoplasma gondii. While palmitoylation is involved in invasion, motility, and cell morphology, the proteins that utilize this PTM remain largely unknown. Using a chemical proteomic approach, we report a comprehensive analysis of palmitoylated proteins in T. gondii, identifying a total of 282 proteins, including cytosolic, membrane-associated, and transmembrane proteins. From this large set of palmitoylated targets, we validate palmitoylation of proteins involved in motility (myosin light chain 1, myosin A), cell morphology (PhIL1), and host cell invasion (apical membrane antigen 1, AMA1). Further studies reveal that blocking AMA1 palmitoylation enhances the release of AMA1 and other invasion-related proteins from apical secretory organelles, suggesting a previously unrecognized role for AMA1. These findings suggest that palmitoylation is ubiquitous throughout the T. gondii proteome and reveal insights into the biology of this important human pathogen.
Collapse
Affiliation(s)
- Ian T Foe
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Matthew A Child
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jaimeen D Majmudar
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Shruthi Krishnamurthy
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
| | | | - Gary E Ward
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
| | - Brent R Martin
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Matthew Bogyo
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| |
Collapse
|
13
|
Absalon S, Robbins JA, Dvorin JD. An essential malaria protein defines the architecture of blood-stage and transmission-stage parasites. Nat Commun 2016; 7:11449. [PMID: 27121004 PMCID: PMC4853479 DOI: 10.1038/ncomms11449] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 03/29/2016] [Indexed: 11/30/2022] Open
Abstract
Blood-stage replication of the human malaria parasite Plasmodium falciparum occurs via schizogony, wherein daughter parasites are formed by a specialized cytokinesis known as segmentation. Here we identify a parasite protein, which we name P. falciparum Merozoite Organizing Protein (PfMOP), as essential for cytokinesis of blood-stage parasites. We show that, following PfMOP knockdown, parasites undergo incomplete segmentation resulting in a residual agglomerate of partially divided cells. While organelles develop normally, the structural scaffold of daughter parasites, the inner membrane complex (IMC), fails to form in this agglomerate causing flawed segmentation. In PfMOP-deficient gametocytes, the IMC formation defect causes maturation arrest with aberrant morphology and death. Our results provide insight into the mechanisms of replication and maturation of malaria parasites. Blood-stage malaria parasites replicate through a specialised type of cell division known as schizogony. Here, Absalon et al. identify a parasite protein that is essential during schizogony for cytokinesis and formation of the inner membrane complex, the structural scaffold of daughter parasites.
Collapse
Affiliation(s)
- Sabrina Absalon
- Division of Infectious Diseases, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Jonathan A Robbins
- Division of Infectious Diseases, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Division of Infectious Diseases, Massachusetts General Hospital/Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
| | - Jeffrey D Dvorin
- Division of Infectious Diseases, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA
| |
Collapse
|
14
|
Harding CR, Egarter S, Gow M, Jiménez-Ruiz E, Ferguson DJP, Meissner M. Gliding Associated Proteins Play Essential Roles during the Formation of the Inner Membrane Complex of Toxoplasma gondii. PLoS Pathog 2016; 12:e1005403. [PMID: 26845335 PMCID: PMC4742064 DOI: 10.1371/journal.ppat.1005403] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/24/2015] [Indexed: 11/18/2022] Open
Abstract
The inner membrane complex (IMC) of apicomplexan parasites is a specialised structure localised beneath the parasite’s plasma membrane, and is important for parasite stability and intracellular replication. Furthermore, it serves as an anchor for the myosin A motor complex, termed the glideosome. While the role of this protein complex in parasite motility and host cell invasion has been well described, additional roles during the asexual life cycle are unknown. Here, we demonstrate that core elements of the glideosome, the gliding associated proteins GAP40 and GAP50 as well as members of the GAPM family, have critical roles in the biogenesis of the IMC during intracellular replication. Deletion or disruption of these genes resulted in the rapid collapse of developing parasites after initiation of the cell cycle and led to redistribution of other glideosome components. Toxoplasma gondii is an important parasite of humans and animals that must actively invade host cells in order to replicate. Beneath the surface of the parasite lies the inner membrane complex (IMC) which is important in maintaining the stability of the parasite, as well as acting as a base for a protein complex known as the glideosome. This assembly of proteins has an important role in allowing the parasite to invade host cells. Here, we examined the function of proteins known to be part of the glideosome, GAP40, GAP50 and five proteins of the GAPM family. We found that in the absence of GAP40 or GAP50, the parasite is able to start replication but is unable to complete it, suggesting that these proteins have a structural role in maintaining the stability of the developing IMC during replication. We also saw that disruption of some members of the GAPM protein family led to a loss of parasite structure. Our study demonstrates that some components of the glideosome have multiple roles in T. gondii biology and gives us new insights into how cells are constructed during parasite replication.
Collapse
Affiliation(s)
- Clare R. Harding
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail: (CRH); (MM)
| | - Saskia Egarter
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Matthew Gow
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Elena Jiménez-Ruiz
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - David J. P. Ferguson
- Nuffield Department of Clinical Laboratory Science, Oxford University, Oxford, United Kingdom
| | - Markus Meissner
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail: (CRH); (MM)
| |
Collapse
|
15
|
Kaneko I, Iwanaga S, Kato T, Kobayashi I, Yuda M. Genome-Wide Identification of the Target Genes of AP2-O, a Plasmodium AP2-Family Transcription Factor. PLoS Pathog 2015; 11:e1004905. [PMID: 26018192 PMCID: PMC4446032 DOI: 10.1371/journal.ppat.1004905] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 04/21/2015] [Indexed: 12/20/2022] Open
Abstract
Stage-specific transcription is a fundamental biological process in the life cycle of the Plasmodium parasite. Proteins containing the AP2 DNA-binding domain are responsible for stage-specific transcriptional regulation and belong to the only known family of transcription factors in Plasmodium parasites. Comprehensive identification of their target genes will advance our understanding of the molecular basis of stage-specific transcriptional regulation and stage-specific parasite development. AP2-O is an AP2 family transcription factor that is expressed in the mosquito midgut-invading stage, called the ookinete, and is essential for normal morphogenesis of this stage. In this study, we identified the genome-wide target genes of AP2-O by chromatin immunoprecipitation-sequencing and elucidate how this AP2 family transcription factor contributes to the formation of this motile stage. The analysis revealed that AP2-O binds specifically to the upstream genomic regions of more than 500 genes, suggesting that approximately 10% of the parasite genome is directly regulated by AP2-O. These genes are involved in distinct biological processes such as morphogenesis, locomotion, midgut penetration, protection against mosquito immunity and preparation for subsequent oocyst development. This direct and global regulation by AP2-O provides a model for gene regulation in Plasmodium parasites and may explain how these parasites manage to control their complex life cycle using a small number of sequence-specific AP2 transcription factors. Although malarial parasites have a complex life cycle, they harbor only 30 transcription factors in their genome. The majority of these transcription factors belong to a single family referred to as the AP2 family. Our previous study suggested that stage-specific AP2 family transcription factors have critical roles in maintaining the Plasmodium parasite life cycle. However, it remains fairly elusive as to how these transcription factors regulate each stage. AP2-O is an AP2 family transcription factor that is expressed during the mosquito midgut-invading stage, the ookinete, and is essential for normal development of this stage. In the present study, we identified the entire set of AP2-O target genes to elucidate how this AP2 family transcription factor contributes to the formation of this stage. Our results showed that AP2-O directly regulates 10% of the parasite genome and is involved in the whole process of mosquito midgut-invasion by ookinetes. The global and comprehensive regulation by the AP2 family transcription factor that we revealed provides a model for transcriptional regulation of this parasite and may explain how malarial parasites regulate their complex life cycle using a small number of sequence-specific transcription factors.
Collapse
Affiliation(s)
- Izumi Kaneko
- Department of Medical Zoology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Shiroh Iwanaga
- Department of Medical Zoology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Tomomi Kato
- Department of Medical Zoology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Issei Kobayashi
- Core-Lab, Graduate School of Regional Innovation Studies, Mie University, Tsu, Mie, Japan
| | - Masao Yuda
- Department of Medical Zoology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
- * E-mail:
| |
Collapse
|
16
|
Lentini G, Kong-Hap M, El Hajj H, Francia M, Claudet C, Striepen B, Dubremetz JF, Lebrun M. Identification and characterization of Toxoplasma SIP, a conserved apicomplexan cytoskeleton protein involved in maintaining the shape, motility and virulence of the parasite. Cell Microbiol 2014; 17:62-78. [PMID: 25088010 DOI: 10.1111/cmi.12337] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/22/2014] [Accepted: 07/24/2014] [Indexed: 12/30/2022]
Abstract
Apicomplexa possess a complex pellicle that is composed of a plasma membrane and a closely apposed inner membrane complex (IMC) that serves as a support for the actin-myosin motor required for motility and host cell invasion. The IMC consists of longitudinal plates of flattened vesicles, fused together and lined on the cytoplasmic side by a subpellicular network of intermediate filament-like proteins. The spatial organization of the IMC has been well described by electron microscopy, but its composition and molecular organization is largely unknown. Here, we identify a novel protein of the IMC cytoskeletal network in Toxoplasma gondii, called TgSIP, and conserved among apicomplexan parasites. To finely pinpoint the localization of TgSIP, we used structured illumination super-resolution microscopy and revealed that it likely decorates the transverse sutures of the plates and the basal end of the IMC. This suggests that TgSIP might contribute to the organization or physical connection among the different components of the IMC. We generated a T.gondii SIP deletion mutant and showed that parasites lacking TgSIP are significantly shorter than wild-type parasites and show defects in gliding motility, invasion and reduced infectivity in mice.
Collapse
Affiliation(s)
- Gaelle Lentini
- UMR 5235 CNRS, Université de Montpellier 1 and 2, 34095, Montpellier, France
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Tilley LD, Krishnamurthy S, Westwood NJ, Ward GE. Identification of TgCBAP, a novel cytoskeletal protein that localizes to three distinct subcompartments of the Toxoplasma gondii pellicle. PLoS One 2014; 9:e98492. [PMID: 24887026 PMCID: PMC4041824 DOI: 10.1371/journal.pone.0098492] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 05/04/2014] [Indexed: 01/17/2023] Open
Abstract
The cytoskeletons of Toxoplasma gondii and related apicomplexan parasites are highly polarized, with apical and basal regions comprised of distinct protein complexes. Components of these complexes are known to play important roles in parasite shape, cell division, and host cell invasion. During an effort to discover the biologically relevant target of a small-molecule inhibitor of T. gondii invasion (Conoidin A), we discovered a novel cytoskeletal protein that we named TgCBAP (Conserved Basal Apical Peripheral protein). Orthologs of TgCBAP are only found in the genomes of other apicomplexans; they contain no identifiable domains or motifs and their function(s) is unknown. As a first step toward elucidating the function of this highly conserved family of proteins, we disrupted the TgCBAP gene by double homologous recombination. Parasites lacking TgCBAP are as sensitive to the effects of Conoidin A as wild-type parasites, demonstrating that TgCBAP is not the biologically relevant target of Conoidin A. However, ΔTgCBAP parasites are significantly shorter than wild-type parasites and have a growth defect in culture. Furthermore, TgCBAP has an unusual subcellular localization, forming small rings at the apical and basal ends of the parasite and localizing to punctate, ring-like structures around the parasite periphery. These data identify a new marker of the apical and basal subcompartments of T. gondii, reveal a potentially novel compartment along the parasite periphery, and identify TgCBAP as a determinant of parasite size that is required for a maximally efficient lytic cycle.
Collapse
Affiliation(s)
- Lucas D. Tilley
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, United States of America
| | - Shruthi Krishnamurthy
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, United States of America
| | - Nicholas J. Westwood
- School of Chemistry and Biomedical Sciences Research Complex, University of St Andrews and EaStCHEM, North Haugh, St Andrews, Fife, Scotland, United Kingdom
| | - Gary E. Ward
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, United States of America
- * E-mail:
| |
Collapse
|
18
|
Harding CR, Meissner M. The inner membrane complex through development of Toxoplasma gondii and Plasmodium. Cell Microbiol 2014; 16:632-41. [PMID: 24612102 PMCID: PMC4286798 DOI: 10.1111/cmi.12285] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 02/20/2014] [Accepted: 02/20/2014] [Indexed: 12/30/2022]
Abstract
Plasmodium spp. and Toxoplasma gondii are important human and veterinary pathogens. These parasites possess an unusual double membrane structure located directly below the plasma membrane named the inner membrane complex (IMC). First identified in early electron micrograph studies, huge advances in genetic manipulation of the Apicomplexa have allowed the visualization of a dynamic, highly structured cellular compartment with important roles in maintaining the structure and motility of these parasites. This review summarizes recent advances in the field and highlights the changes the IMC undergoes during the complex life cycles of the Apicomplexa.
Collapse
Affiliation(s)
- Clare R Harding
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, The University of Glasgow, Glasgow, UK
| | | |
Collapse
|
19
|
Disruption of TgPHIL1 alters specific parameters of Toxoplasma gondii motility measured in a quantitative, three-dimensional live motility assay. PLoS One 2014; 9:e85763. [PMID: 24489670 PMCID: PMC3906025 DOI: 10.1371/journal.pone.0085763] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 11/30/2013] [Indexed: 01/15/2023] Open
Abstract
T. gondii uses substrate-dependent gliding motility to invade cells of its hosts, egress from these cells at the end of its lytic cycle and disseminate through the host organism during infection. The ability of the parasite to move is therefore critical for its virulence. T. gondii engages in three distinct types of gliding motility on coated two-dimensional surfaces: twirling, circular gliding and helical gliding. We show here that motility in a three-dimensional Matrigel-based environment is strikingly different, in that all parasites move in irregular corkscrew-like trajectories. Methods developed for quantitative analysis of motility parameters along the smoothed trajectories demonstrate a complex but periodic pattern of motility with mean and maximum velocities of 0.58±0.07 µm/s and 2.01±0.17 µm/s, respectively. To test how a change in the parasite's crescent shape might affect trajectory parameters, we compared the motility of Δphil1 parasites, which are shorter and wider than wild type, to the corresponding parental and complemented lines. Although comparable percentages of parasites were moving for all three lines, the Δphil1 mutant exhibited significantly decreased trajectory lengths and mean and maximum velocities compared to the parental parasite line. These effects were either partially or fully restored upon complementation of the Δphil1 mutant. These results show that alterations in morphology may have a significant impact on T. gondii motility in an extracellular matrix-like environment, provide a possible explanation for the decreased fitness of Δphil1 parasites in vivo, and demonstrate the utility of the quantitative three-dimensional assay for studying parasite motility.
Collapse
|
20
|
Tremp AZ, Carter V, Saeed S, Dessens JT. Morphogenesis of Plasmodium zoites is uncoupled from tensile strength. Mol Microbiol 2013; 89:552-64. [PMID: 23773015 PMCID: PMC3912903 DOI: 10.1111/mmi.12297] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2013] [Indexed: 12/17/2022]
Abstract
A shared feature of the motile stages (zoites) of malaria parasites is a cortical cytoskeletal structure termed subpellicular network (SPN), thought to define and maintain cell shape. Plasmodium alveolins comprise structural components of the SPN, and alveolin gene knockout causes morphological abnormalities that coincide with markedly reduced tensile strength of the affected zoites, indicating the alveolins are prime cell shape determinants. Here, we characterize a novel SPN protein of Plasmodium berghei ookinetes and sporozoites named G2 (glycine at position 2), which is structurally unrelated to alveolins. G2 knockout abolishes parasite transmission and causes zoite malformations and motility defects similar to those observed in alveolin null mutants. Unlike alveolins, however, G2 contributes little to tensile strength, arguing against a cause-effect relationship between tensile strength and cell shape. We also show that G2 null mutant sporozoites display an abnormal arrangement of their subpellicular microtubules. These results provide important new understanding of the factors that determine zoite morphogenesis, as well as the potential roles of the cortical cytoskeleton in gliding motility.
Collapse
Affiliation(s)
- Annie Z Tremp
- Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | | | | | | |
Collapse
|
21
|
Dubremetz JF, Lebrun M. Virulence factors of Toxoplasma gondii. Microbes Infect 2012; 14:1403-10. [PMID: 23006855 DOI: 10.1016/j.micinf.2012.09.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 09/03/2012] [Accepted: 09/04/2012] [Indexed: 11/28/2022]
Abstract
Toxoplasma gondii virulence is dependent on factors involved in either parasite-host cell interaction, or in host immune response. It is essentially defined in the mouse and little is known concerning human infection. The genetic dependence of virulence is a growing field, benefiting from the recent development of research of the population structure of T. gondii.
Collapse
Affiliation(s)
- Jean François Dubremetz
- UMR 5235 CNRS, Université de Montpellier 2, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France.
| | | |
Collapse
|
22
|
Anderson-White B, Beck JR, Chen CT, Meissner M, Bradley PJ, Gubbels MJ. Cytoskeleton assembly in Toxoplasma gondii cell division. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 298:1-31. [PMID: 22878103 PMCID: PMC4066374 DOI: 10.1016/b978-0-12-394309-5.00001-8] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Cell division across members of the protozoan parasite phylum Apicomplexa displays a surprising diversity between different species as well as between different life stages of the same parasite. In most cases, infection of a host cell by a single parasite results in the formation of a polyploid cell from which individual daughters bud in a process dependent on a final round of mitosis. Unlike other apicomplexans, Toxoplasma gondii divides by a binary process consisting of internal budding that results in only two daughter cells per round of division. Since T. gondii is experimentally accessible and displays the simplest division mode, it has manifested itself as a model for apicomplexan daughter formation. Here, we review newly emerging insights in the prominent role that assembly of the cortical cytoskeletal scaffold plays in the process of daughter parasite formation.
Collapse
Affiliation(s)
| | - Josh R. Beck
- University of California Los Angeles, Department of Microbiology, Immunology and Molecular Genetics, Los Angeles, CA 90095, USA
| | - Chun-Ti Chen
- Boston College, Department of Biology, Chestnut Hill, MA 02467, USA
| | - Markus Meissner
- Division of Infection and Immunity, Institute of Biomedical Life Sciences, Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow G12 8TA, UK
| | - Peter J. Bradley
- University of California Los Angeles, Department of Microbiology, Immunology and Molecular Genetics, Los Angeles, CA 90095, USA
| | - Marc-Jan Gubbels
- Boston College, Department of Biology, Chestnut Hill, MA 02467, USA
| |
Collapse
|