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Currie-Olsen D, Leander BS. Novel cytoskeletal traits in the intestinal parasites (Squirmida, Platyproteum vivax) of Pacific peanut worms (Sipuncula, Phascolosoma agassizii). J Eukaryot Microbiol 2024; 71:e13023. [PMID: 38402546 DOI: 10.1111/jeu.13023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/18/2024] [Accepted: 02/11/2024] [Indexed: 02/26/2024]
Abstract
The cytoskeletal organization of a squirmid, namely Platyproteum vivax, was investigated with confocal laser scanning microscopy (CLSM) to refine inferences about convergent evolution among intestinal parasites of marine invertebrates. Platyproteum inhabits Pacific peanut worms (Phascolosoma agassizii) and has traits that are similar to other lineages of myzozoan parasites, namely gregarine apicomplexans within Selenidium, such as conspicuous feeding stages, called "trophozoites," capable of dynamic undulations. SEM and CLSM of P. vivax revealed an inconspicuous flagellar apparatus and a uniform array of longitudinal microtubules organized in bundles (LMBs). Extreme flattening of the trophozoites and a consistently oblique morphology of the anterior end provided a reliable way to distinguish dorsal and ventral surfaces. CLSM revealed a novel system of microtubules oriented in the flattened dorsoventral plane. Most of these dorsoventral microtubule bundles (DVMBs) had a punctate distribution and were evenly spaced along a curved line spanning the longitudinal axis of the trophozoites. This configuration of microtubules is inferred to function in maintaining the flattened shape of the trophozoites and facilitate dynamic undulations. The novel traits in Platyproteum are consistent with phylogenomic data showing that this lineage is only distantly related to Selenidium and other marine gregarine apicomplexans with dynamic intestinal trophozoites.
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Affiliation(s)
- Danja Currie-Olsen
- Department of Zoology, Beaty Biodiversity Research Centre and Museum, University of British Columbia, Vancouver, British Columbia, Canada
- Hakai Institute, Heriot Bay, Quadra Island, British Columbia, Canada
| | - Brian S Leander
- Department of Zoology, Beaty Biodiversity Research Centre and Museum, University of British Columbia, Vancouver, British Columbia, Canada
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2
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Kellermeier JA, Heaslip AT. Myosin F controls actin organization and dynamics in Toxoplasma gondii. Mol Biol Cell 2024; 35:ar57. [PMID: 38416592 PMCID: PMC11064658 DOI: 10.1091/mbc.e23-12-0510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/14/2024] [Accepted: 02/21/2024] [Indexed: 03/01/2024] Open
Abstract
Intracellular cargo transport is a ubiquitous cellular process in all eukaryotes. In many cell types, membrane bound cargo is associated with molecular motors which transport cargo along microtubule and actin tracks. In Toxoplasma gondii (T. gondii), an obligate intracellular parasite in the phylum Apicomplexa, organization of the endomembrane pathway depends on actin and an unconventional myosin motor, myosin F (MyoF). Loss of MyoF and actin disrupts vesicle transport, organelle positioning, and division of the apicoplast, a nonphotosynthetic plastid organelle. How this actomyosin system contributes to these cellular functions is still unclear. Using live-cell imaging, we observed that MyoF-EmeraldFP (MyoF-EmFP) displayed a dynamic and filamentous-like organization in the parasite cytosol, reminiscent of cytosolic actin filament dynamics. MyoF was not associated with the Golgi, apicoplast or dense granule surfaces, suggesting that it does not function using the canonical cargo transport mechanism. Instead, we found that loss of MyoF resulted in a dramatic rearrangement of the actin cytoskeleton in interphase parasites accompanied by significantly reduced actin dynamics. However, actin organization during parasite replication and motility was unaffected by the loss of MyoF. These findings revealed that MyoF is an actin organizing protein in Toxoplasma and facilitates cargo movement using an unconventional transport mechanism.
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Affiliation(s)
- Jacob A. Kellermeier
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269
| | - Aoife T. Heaslip
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269
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3
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Ribeiro R, Costa L, Pinto E, Sousa E, Fernandes C. Therapeutic Potential of Marine-Derived Cyclic Peptides as Antiparasitic Agents. Mar Drugs 2023; 21:609. [PMID: 38132930 PMCID: PMC10745025 DOI: 10.3390/md21120609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 11/18/2023] [Accepted: 11/23/2023] [Indexed: 12/23/2023] Open
Abstract
Parasitic diseases still compromise human health. Some of the currently available therapeutic drugs have limitations considering their adverse effects, questionable efficacy, and long treatment, which have encouraged drug resistance. There is an urgent need to find new, safe, effective, and affordable antiparasitic drugs. Marine-derived cyclic peptides have been increasingly screened as candidates for developing new drugs. Therefore, in this review, a systematic analysis of the scientific literature was performed and 25 marine-derived cyclic peptides with antiparasitic activity (1-25) were found. Antimalarial activity is the most reported (51%), followed by antileishmanial (27%) and antitrypanosomal (20%) activities. Some compounds showed promising antiparasitic activity at the nM scale, being active against various parasites. The mechanisms of action and targets for some of the compounds have been investigated, revealing different strategies against parasites.
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Affiliation(s)
- Ricardo Ribeiro
- Laboratório de Química Orgânica e Farmacêutica, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal; (R.R.); (L.C.); (E.S.)
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), Edifício do Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4050-208 Matosinhos, Portugal;
| | - Lia Costa
- Laboratório de Química Orgânica e Farmacêutica, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal; (R.R.); (L.C.); (E.S.)
| | - Eugénia Pinto
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), Edifício do Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4050-208 Matosinhos, Portugal;
- Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
| | - Emília Sousa
- Laboratório de Química Orgânica e Farmacêutica, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal; (R.R.); (L.C.); (E.S.)
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), Edifício do Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4050-208 Matosinhos, Portugal;
| | - Carla Fernandes
- Laboratório de Química Orgânica e Farmacêutica, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal; (R.R.); (L.C.); (E.S.)
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), Edifício do Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4050-208 Matosinhos, Portugal;
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Martinez M, Mageswaran SK, Guérin A, Chen WD, Thompson CP, Chavin S, Soldati-Favre D, Striepen B, Chang YW. Origin and arrangement of actin filaments for gliding motility in apicomplexan parasites revealed by cryo-electron tomography. Nat Commun 2023; 14:4800. [PMID: 37558667 PMCID: PMC10412601 DOI: 10.1038/s41467-023-40520-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 07/26/2023] [Indexed: 08/11/2023] Open
Abstract
The phylum Apicomplexa comprises important eukaryotic parasites that invade host tissues and cells using a unique mechanism of gliding motility. Gliding is powered by actomyosin motors that translocate host-attached surface adhesins along the parasite cell body. Actin filaments (F-actin) generated by Formin1 play a central role in this critical parasitic activity. However, their subcellular origin, path and ultrastructural arrangement are poorly understood. Here we used cryo-electron tomography to image motile Cryptosporidium parvum sporozoites and reveal the cellular architecture of F-actin at nanometer-scale resolution. We demonstrate that F-actin nucleates at the apically positioned preconoidal rings and is channeled into the pellicular space between the parasite plasma membrane and the inner membrane complex in a conoid extrusion-dependent manner. Within the pellicular space, filaments on the inner membrane complex surface appear to guide the apico-basal flux of F-actin. F-actin concordantly accumulates at the basal end of the parasite. Finally, analyzing a Formin1-depleted Toxoplasma gondii mutant pinpoints the upper preconoidal ring as the conserved nucleation hub for F-actin in Cryptosporidium and Toxoplasma. Together, we provide an ultrastructural model for the life cycle of F-actin for apicomplexan gliding motility.
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Affiliation(s)
- Matthew Martinez
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Shrawan Kumar Mageswaran
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute of Structural Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Amandine Guérin
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - William David Chen
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Cameron Parker Thompson
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Sabine Chavin
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, USA
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Boris Striepen
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yi-Wei Chang
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Institute of Structural Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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5
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Pavlou G, Touquet B, Vigetti L, Renesto P, Bougdour A, Debarre D, Balland M, Tardieux I. Coupling Polar Adhesion with Traction, Spring, and Torque Forces Allows High-Speed Helical Migration of the Protozoan Parasite Toxoplasma. ACS NANO 2020; 14:7121-7139. [PMID: 32432851 DOI: 10.1021/acsnano.0c01893] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Among the eukaryotic cells that navigate through fully developed metazoan tissues, protozoans from the Apicomplexa phylum have evolved motile developmental stages that move much faster than the fastest crawling cells owing to a peculiar substrate-dependent type of motility, known as gliding. Best-studied models are the Plasmodium sporozoite and the Toxoplasma tachyzoite polarized cells for which motility is vital to achieve their developmental programs in the metazoan hosts. The gliding machinery is shared between the two parasites and is largely characterized. Localized beneath the cell surface, it includes actin filaments, unconventional myosin motors housed within a multimember glideosome unit, and apically secreted transmembrane adhesins. In contrast, less is known about the force mechanisms powering cell movement. Pioneered biophysical studies on the sporozoite and phenotypic analysis of tachyzoite actin-related mutants have added complexity to the general view that force production for parasite forward movement directly results from the myosin-driven rearward motion of the actin-coupled adhesion sites. Here, we have interrogated how forces and substrate adhesion-de-adhesion cycles operate and coordinate to allow the typical left-handed helical gliding mode of the tachyzoite. By combining quantitative traction force and reflection interference microscopy with micropatterning and expansion microscopy, we unveil at the millisecond and nanometer scales the integration of a critical apical anchoring adhesion with specific traction and spring-like forces. We propose that the acto-myoA motor directs the traction force which allows transient energy storage by the microtubule cytoskeleton and therefore sets the thrust force required for T. gondii tachyzoite vital helical gliding capacity.
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Affiliation(s)
- Georgios Pavlou
- Institute for Advanced Biosciences (IAB), Team Membrane Dynamics of Parasite-Host Cell Interactions, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, 38700 Grenoble, France
| | - Bastien Touquet
- Institute for Advanced Biosciences (IAB), Team Membrane Dynamics of Parasite-Host Cell Interactions, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, 38700 Grenoble, France
| | - Luis Vigetti
- Institute for Advanced Biosciences (IAB), Team Membrane Dynamics of Parasite-Host Cell Interactions, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, 38700 Grenoble, France
| | - Patricia Renesto
- Institute for Advanced Biosciences (IAB), Team Membrane Dynamics of Parasite-Host Cell Interactions, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, 38700 Grenoble, France
- TIMC-IMAG UMR 5525 - UGA CNRS, 38700 Grenoble, France
| | - Alexandre Bougdour
- Institute for Advanced Biosciences (IAB), Team Host-Pathogen Interactions & Immunity to Infections, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, 38700 Grenoble, France
| | - Delphine Debarre
- Laboratoire Interdisciplinaire de Physique, UMR CNRS, 5588, Université Grenoble Alpes, Grenoble 38402, France
| | - Martial Balland
- Laboratoire Interdisciplinaire de Physique, UMR CNRS, 5588, Université Grenoble Alpes, Grenoble 38402, France
| | - Isabelle Tardieux
- Institute for Advanced Biosciences (IAB), Team Membrane Dynamics of Parasite-Host Cell Interactions, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, 38700 Grenoble, France
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6
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Hunt A, Russell MRG, Wagener J, Kent R, Carmeille R, Peddie CJ, Collinson L, Heaslip A, Ward GE, Treeck M. Differential requirements for cyclase-associated protein (CAP) in actin-dependent processes of Toxoplasma gondii. eLife 2019; 8:e50598. [PMID: 31577230 PMCID: PMC6785269 DOI: 10.7554/elife.50598] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 09/26/2019] [Indexed: 12/26/2022] Open
Abstract
Toxoplasma gondii contains a limited subset of actin binding proteins. Here we show that the putative actin regulator cyclase-associated protein (CAP) is present in two different isoforms and its deletion leads to significant defects in some but not all actin dependent processes. We observe defects in cell-cell communication, daughter cell orientation and the juxtanuclear accumulation of actin, but only modest defects in synchronicity of division and no defect in the replication of the apicoplast. 3D electron microscopy reveals that loss of CAP results in a defect in formation of a normal central residual body, but parasites remain connected within the vacuole. This dissociates synchronicity of division and parasite rosetting and reveals that establishment and maintenance of the residual body may be more complex than previously thought. These results highlight the different spatial requirements for F-actin regulation in Toxoplasma which appear to be achieved by partially overlapping functions of actin regulators.
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Affiliation(s)
- Alex Hunt
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | | | - Jeanette Wagener
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Robyn Kent
- Department of Microbiology and Molecular GeneticsUniversity of Vermont Larner College of MedicineBurlingtonUnited States
| | - Romain Carmeille
- Department of Molecular and Cell BiologyUniversity of ConnecticutStorrsUnited States
| | - Christopher J Peddie
- Electron Microscopy Science Technology Platform, The Francis Crick InstituteLondonUnited Kingdom
| | - Lucy Collinson
- Electron Microscopy Science Technology Platform, The Francis Crick InstituteLondonUnited Kingdom
| | - Aoife Heaslip
- Department of Molecular and Cell BiologyUniversity of ConnecticutStorrsUnited States
| | - Gary E Ward
- Department of Microbiology and Molecular GeneticsUniversity of Vermont Larner College of MedicineBurlingtonUnited States
| | - Moritz Treeck
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
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7
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Tosetti N, Dos Santos Pacheco N, Soldati-Favre D, Jacot D. Three F-actin assembly centers regulate organelle inheritance, cell-cell communication and motility in Toxoplasma gondii. eLife 2019; 8:e42669. [PMID: 30753127 PMCID: PMC6372287 DOI: 10.7554/elife.42669] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 01/29/2019] [Indexed: 01/06/2023] Open
Abstract
Toxoplasma gondii possesses a limited set of actin-regulatory proteins and relies on only three formins (FRMs) to nucleate and polymerize actin. We combined filamentous actin (F-actin) chromobodies with gene disruption to assign specific populations of actin filaments to individual formins. FRM2 localizes to the apical juxtanuclear region and participates in apicoplast inheritance. Restricted to the residual body, FRM3 maintains the intravacuolar cell-cell communication. Conoidal FRM1 initiates a flux of F-actin crucial for motility, invasion and egress. This flux depends on myosins A and H and is controlled by phosphorylation via PKG (protein kinase G) and CDPK1 (calcium-dependent protein kinase 1) and by methylation via AKMT (apical lysine methyltransferase). This flux is independent of microneme secretion and persists in the absence of the glideosome-associated connector (GAC). This study offers a coherent model of the key players controlling actin polymerization, stressing the importance of well-timed post-translational modifications to power parasite motility.
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Affiliation(s)
- Nicolò Tosetti
- Department of Microbiology and Molecular Medicine, CMUUniversity of GenevaGenevaSwitzerland
| | | | | | - Damien Jacot
- Department of Microbiology and Molecular Medicine, CMUUniversity of GenevaGenevaSwitzerland
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8
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Actin from the apicomplexan Neospora caninum (NcACT) has different isoforms in 2D electrophoresis. Parasitology 2018; 146:33-41. [PMID: 29871709 DOI: 10.1017/s0031182018000872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Apicomplexan parasites have unconventional actins that play a central role in important cellular processes such as apicoplast replication, motility of dense granules, endocytic trafficking and force generation for motility and host cell invasion. In this study, we investigated the actin of the apicomplexan Neospora caninum - a parasite associated with infectious abortion and neonatal mortality in livestock. Neospora caninum actin was detected and identified in two bands by one-dimensional (1D) western blot and in nine spots by the 2D technique. The mass spectrometry data indicated that N. caninum has at least nine different actin isoforms, possibly caused by post-translational modifications. In addition, the C4 pan-actin antibody detected specifically actin in N. caninum cellular extract. Extracellular N. caninum tachyzoites were treated with toxins that act on actin, jasplakinolide and cytochalasin D. Both substances altered the peripheric cytoplasmic localization of actin on tachyzoites. Our findings add complexity to the study of the apicomplexan actin in cellular processes, since the multiple functions of this important protein might be regulated by mechanisms involving post-translational modifications.
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9
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Curra C, McMillan PJ, Spanos L, Mollard V, Deligianni E, McFadden G, Tilley L, Siden-Kiamos I. Structured illumination microscopy reveals actin I localization in discreet foci in Plasmodium berghei gametocytes. Exp Parasitol 2017; 181:82-87. [PMID: 28803903 DOI: 10.1016/j.exppara.2017.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 06/30/2017] [Accepted: 08/08/2017] [Indexed: 11/26/2022]
Abstract
Actin has important roles in Plasmodium parasites but its exact function in different life stages is not yet fully elucidated. Here we report the localization of ubiquitous actin I in gametocytes of the rodent model parasite P. berghei. Using an antibody specifically recognizing F-actin and deconvolution microscopy we detected actin I in a punctate pattern in gametocytes. 3D-Structured Illumination Microscopy which allows sub-diffraction limit imaging resolved the signal into structures of less than 130 nm length. A portion of actin I was soluble, but the protein was also found complexed in a stabilized form which could only be completely solubilized by treatment with SDS. An additional population of actin was pelleted at 100 000 × g, consistent with F-actin. Our results suggest that actin in this non-motile form of the parasite is present in short filaments cross-linked to other structures in a cytoskeleton.
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Affiliation(s)
- Chiara Curra
- Institute of Molecular Biology and Biotechnology, FORTH, Heraklion, Greece
| | - Paul J McMillan
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, 3051 VIC, Australia; Biological Optical Microscopy Platform, The University of Melbourne, Melbourne, 3051 VIC, Australia
| | - Lefteris Spanos
- Institute of Molecular Biology and Biotechnology, FORTH, Heraklion, Greece
| | - Vanessa Mollard
- School of BioSciences, The University of Melbourne, Melbourne, 3051 VIC, Australia
| | - Elena Deligianni
- Institute of Molecular Biology and Biotechnology, FORTH, Heraklion, Greece
| | - Geoffrey McFadden
- School of BioSciences, The University of Melbourne, Melbourne, 3051 VIC, Australia
| | - Leann Tilley
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, 3051 VIC, Australia
| | - Inga Siden-Kiamos
- Institute of Molecular Biology and Biotechnology, FORTH, Heraklion, Greece.
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Lateral diffusion and signaling of receptor for advanced glycation end-products (RAGE): a receptor involved in chronic inflammation. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2017. [DOI: 10.1007/s00249-017-1227-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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11
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Stadler RV, White LA, Hu K, Helmke BP, Guilford WH. Direct measurement of cortical force generation and polarization in a living parasite. Mol Biol Cell 2017; 28:1912-1923. [PMID: 28209732 PMCID: PMC5541842 DOI: 10.1091/mbc.e16-07-0518] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 01/19/2017] [Accepted: 02/10/2017] [Indexed: 02/04/2023] Open
Abstract
Apicomplexa is a large phylum of intracellular parasites that are notable for the diseases they cause, including toxoplasmosis, malaria, and cryptosporidiosis. A conserved motile system is critical to their life cycles and drives directional gliding motility between cells, as well as invasion of and egress from host cells. However, our understanding of this system is limited by a lack of measurements of the forces driving parasite motion. We used a laser trap to measure the function of the motility apparatus of living Toxoplasma gondii by adhering a microsphere to the surface of an immobilized parasite. Motion of the microsphere reflected underlying forces exerted by the motile apparatus. We found that force generated at the parasite surface begins with no preferential directionality but becomes directed toward the rear of the cell after a period of time. The transition from nondirectional to directional force generation occurs on spatial intervals consistent with the lateral periodicity of structures associated with the membrane pellicle and is influenced by the kinetics of actin filament polymerization and cytoplasmic calcium. A lysine methyltransferase regulates both the magnitude and polarization of the force. Our work provides a novel means to dissect the motile mechanisms of these pathogens.
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Affiliation(s)
- Rachel V Stadler
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908
| | - Lauren A White
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908
| | - Ke Hu
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Brian P Helmke
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908
| | - William H Guilford
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908
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12
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Jacot D, Tosetti N, Pires I, Stock J, Graindorge A, Hung YF, Han H, Tewari R, Kursula I, Soldati-Favre D. An Apicomplexan Actin-Binding Protein Serves as a Connector and Lipid Sensor to Coordinate Motility and Invasion. Cell Host Microbe 2016; 20:731-743. [PMID: 27978434 DOI: 10.1016/j.chom.2016.10.020] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/16/2016] [Accepted: 10/27/2016] [Indexed: 01/06/2023]
Abstract
Apicomplexa exhibit a unique form of substrate-dependent gliding motility central for host cell invasion and parasite dissemination. Gliding is powered by rearward translocation of apically secreted transmembrane adhesins via their interaction with the parasite actomyosin system. We report a conserved armadillo and pleckstrin homology (PH) domain-containing protein, termed glideosome-associated connector (GAC), that mediates apicomplexan gliding motility, invasion, and egress by connecting the micronemal adhesins with the actomyosin system. TgGAC binds to and stabilizes filamentous actin and specifically associates with the transmembrane adhesin TgMIC2. GAC localizes to the apical pole in invasive stages of Toxoplasma gondii and Plasmodium berghei, and apical positioning of TgGAC depends on an apical lysine methyltransferase, TgAKMT. GAC PH domain also binds to phosphatidic acid, a lipid mediator associated with microneme exocytosis. Collectively, these findings indicate a central role for GAC in spatially and temporally coordinating gliding motility and invasion.
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Affiliation(s)
- Damien Jacot
- Department of Microbiology & Molecular Medicine, University of Geneva, 1 Rue Michel-Servet, 1211 Geneva, Switzerland
| | - Nicolò Tosetti
- Department of Microbiology & Molecular Medicine, University of Geneva, 1 Rue Michel-Servet, 1211 Geneva, Switzerland
| | - Isa Pires
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7, 90220 Oulu, Finland
| | - Jessica Stock
- School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG2 7UH, UK
| | - Arnault Graindorge
- Department of Microbiology & Molecular Medicine, University of Geneva, 1 Rue Michel-Servet, 1211 Geneva, Switzerland
| | - Yu-Fu Hung
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7, 90220 Oulu, Finland
| | - Huijong Han
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7, 90220 Oulu, Finland
| | - Rita Tewari
- School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG2 7UH, UK
| | - Inari Kursula
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7, 90220 Oulu, Finland; Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway.
| | - Dominique Soldati-Favre
- Department of Microbiology & Molecular Medicine, University of Geneva, 1 Rue Michel-Servet, 1211 Geneva, Switzerland.
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Sato Y, Hliscs M, Dunst J, Goosmann C, Brinkmann V, Montagna GN, Matuschewski K. Comparative Plasmodium gene overexpression reveals distinct perturbation of sporozoite transmission by profilin. Mol Biol Cell 2016; 27:2234-44. [PMID: 27226484 PMCID: PMC4945141 DOI: 10.1091/mbc.e15-10-0734] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 05/16/2016] [Indexed: 12/27/2022] Open
Abstract
The roles of vital genes, such as those of G-actin–binding proteins, in malaria parasites are underexplored. Overexpression of Plasmodium profilin perturbs actin dynamics only in sporozoites. Strict actin regulation is particularly important for malaria transmission. Mapping of phenotypes can be done by comparative Plasmodium gene overexpression. Plasmodium relies on actin-based motility to migrate from the site of infection and invade target cells. Using a substrate-dependent gliding locomotion, sporozoites are able to move at fast speed (1–3 μm/s). This motility relies on a minimal set of actin regulatory proteins and occurs in the absence of detectable filamentous actin (F-actin). Here we report an overexpression strategy to investigate whether perturbations of F-actin steady-state levels affect gliding locomotion and host invasion. We selected two vital Plasmodium berghei G-actin–binding proteins, C-CAP and profilin, in combination with three stage-specific promoters and mapped the phenotypes afforded by overexpression in all three extracellular motile stages. We show that in merozoites and ookinetes, additional expression does not impair life cycle progression. In marked contrast, overexpression of C-CAP and profilin in sporozoites impairs circular gliding motility and salivary gland invasion. The propensity for productive motility correlates with actin accumulation at the parasite tip, as revealed by combinations of an actin-stabilizing drug and transgenic parasites. Strong expression of profilin, but not C-CAP, resulted in complete life cycle arrest. Comparative overexpression is an alternative experimental genetic strategy to study essential genes and reveals effects of regulatory imbalances that are not uncovered from deletion-mutant phenotyping.
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Affiliation(s)
- Yuko Sato
- Parasitology Unit, Max Planck Institute for Infection Biology, 10117 Berlin, Germany Infectious Diseases Interdisciplinary Research Group, Singapore-Massachusetts Institute of Technology Alliance for Research and Technology, 138602 Singapore
| | - Marion Hliscs
- Parasitology Unit, Max Planck Institute for Infection Biology, 10117 Berlin, Germany School of BioSciences, University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Josefine Dunst
- Parasitology Unit, Max Planck Institute for Infection Biology, 10117 Berlin, Germany Institute for Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Christian Goosmann
- Imaging Unit, Max Planck Institute for Infection Biology, 10117 Berlin, Germany
| | - Volker Brinkmann
- Imaging Unit, Max Planck Institute for Infection Biology, 10117 Berlin, Germany
| | - Georgina N Montagna
- Parasitology Unit, Max Planck Institute for Infection Biology, 10117 Berlin, Germany Departamento de Microbiologia, Immunologia e Parasitologia, Universidade Federal de São Paulo, 04039-032 São Paulo, Brazil
| | - Kai Matuschewski
- Parasitology Unit, Max Planck Institute for Infection Biology, 10117 Berlin, Germany Institute of Biology, Humboldt University, 10117 Berlin, Germany
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14
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Quadt KA, Streichfuss M, Moreau CA, Spatz JP, Frischknecht F. Coupling of Retrograde Flow to Force Production During Malaria Parasite Migration. ACS NANO 2016; 10:2091-2102. [PMID: 26792112 DOI: 10.1021/acsnano.5b06417] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Migration of malaria parasites is powered by a myosin motor that moves actin filaments, which in turn link to adhesive proteins spanning the plasma membrane. The retrograde flow of these adhesins appears to be coupled to forward locomotion. However, the contact dynamics between the parasite and the substrate as well as the generation of forces are complex and their relation to retrograde flow is unclear. Using optical tweezers we found retrograde flow rates up to 15 μm/s contrasting with parasite average speeds of 1-2 μm/s. We found that a surface protein, TLP, functions in reducing retrograde flow for the buildup of adhesive force and that actin dynamics appear optimized for the generation of force but not for maximizing the speed of retrograde flow. These data uncover that TLP acts by modulating actin dynamics or actin filament organization and couples retrograde flow to force production in malaria parasites.
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Affiliation(s)
- Katharina A Quadt
- Integrative Parasitology, Center for Infectious Diseases, University of Heidelberg Medical School , Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Martin Streichfuss
- Integrative Parasitology, Center for Infectious Diseases, University of Heidelberg Medical School , Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
- University of Heidelberg , Department of Biophysical Chemistry and Max Planck Institute for Intelligent Systems, Department of New Materials and Biosystems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Catherine A Moreau
- Integrative Parasitology, Center for Infectious Diseases, University of Heidelberg Medical School , Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Joachim P Spatz
- University of Heidelberg , Department of Biophysical Chemistry and Max Planck Institute for Intelligent Systems, Department of New Materials and Biosystems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, University of Heidelberg Medical School , Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
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15
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Actin-Dynamics in Plant Cells: The Function of Actin-Perturbing Substances: Jasplakinolide, Chondramides, Phalloidin, Cytochalasins, and Latrunculins. Methods Mol Biol 2016; 1365:243-61. [PMID: 26498789 DOI: 10.1007/978-1-4939-3124-8_13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This chapter gives an overview of the most common F-actin-perturbing substances that are used to study actin dynamics in living plant cells in studies on morphogenesis, motility, organelle movement, or when apoptosis has to be induced. These substances can be divided into two major subclasses: F-actin-stabilizing and -polymerizing substances like jasplakinolide and chondramides and F-actin-severing compounds like chytochalasins and latrunculins. Jasplakinolide was originally isolated form a marine sponge, and can now be synthesized and has become commercially available, which is responsible for its wide distribution as membrane-permeable F-actin-stabilizing and -polymerizing agent, which may even have anticancer activities. Cytochalasins, derived from fungi, show an F-actin-severing function and many derivatives are commercially available (A, B, C, D, E, H, J), also making it a widely used compound for F-actin disruption. The same can be stated for latrunculins (A, B), derived from red sea sponges; however the mode of action is different by binding to G-actin and inhibiting incorporation into the filament. In the case of swinholide a stable complex with actin dimers is formed resulting also in severing of F-actin. For influencing F-actin dynamics in plant cells only membrane permeable drugs are useful in a broad range. We however introduce also the phallotoxins and synthetic derivatives, as they are widely used to visualize F-actin in fixed cells. A particular uptake mechanism has been shown for hepatocytes, but has also been described in siphonal giant algae. In the present chapter the focus is set on F-actin dynamics in plant cells where alterations in cytoplasmic streaming can be particularly well studied; however methods by fluorescence applications including phalloidin and antibody staining as well as immunofluorescence-localization of the inhibitor drugs are given.
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16
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Olshina MA, Baumann H, Willison KR, Baum J. Plasmodium actin is incompletely folded by heterologous protein-folding machinery and likely requires the native Plasmodium chaperonin complex to enter a mature functional state. FASEB J 2015; 30:405-16. [PMID: 26443825 PMCID: PMC5423778 DOI: 10.1096/fj.15-276618] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 09/14/2015] [Indexed: 12/18/2022]
Abstract
Actin filament turnover underpins several processes in the life cycle of the malaria parasite, Plasmodium falciparum. Polymerization and depolymerization are especially important for gliding motility, a substrate-dependent form of cell movement that underpins the protozoan parasite’s ability to disseminate and invade host cells. To date, given difficulties in extraction of native actins directly from parasites, much of our biochemical understanding of malarial actin has instead relied on recombinant protein extracted and purified from heterologous protein expression systems. Here, using in vitro transcription-translation methodologies and quantitative protein-binding assays, we explored the folding state of heterologously expressed P. falciparum actin 1 (PfACTI) with the aim of assessing the reliability of current recombinant-protein-based data. We demonstrate that PfACTI, when expressed in non-native systems, is capable of binding to and release from bacterial, yeast, and mammalian chaperonin complexes but appears to be incompletely folded. Characterization of the native Plasmodium folding machinery in silico, the chaperonin containing t-complex protein-1 complex, highlights key divergences between the different chaperonin systems that likely underpins this incomplete folded state. These results highlight the importance of characterizing actin’s folded state and raise concerns about the interpretation of actin polymerization kinetics based solely on protein derived from heterologous expression systems.—Olshina, M. A., Baumann, H., Willison, K. R., Baum, J. Plasmodium actin is incompletely folded by heterologous protein-folding machinery and likely requires the native Plasmodium chaperonin complex to enter a mature functional state.
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Affiliation(s)
- Maya A Olshina
- *Walter and Eliza Hall Institute of Medical Research and Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia; Department of Life Sciences and Department of Chemistry, Imperial College London, South Kensington, London, United Kingdom
| | - Hella Baumann
- *Walter and Eliza Hall Institute of Medical Research and Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia; Department of Life Sciences and Department of Chemistry, Imperial College London, South Kensington, London, United Kingdom
| | - Keith R Willison
- *Walter and Eliza Hall Institute of Medical Research and Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia; Department of Life Sciences and Department of Chemistry, Imperial College London, South Kensington, London, United Kingdom
| | - Jake Baum
- *Walter and Eliza Hall Institute of Medical Research and Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia; Department of Life Sciences and Department of Chemistry, Imperial College London, South Kensington, London, United Kingdom
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17
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Haase S, Zimmermann D, Olshina MA, Wilkinson M, Fisher F, Tan YH, Stewart RJ, Tonkin CJ, Wong W, Kovar DR, Baum J. Disassembly activity of actin-depolymerizing factor (ADF) is associated with distinct cellular processes in apicomplexan parasites. Mol Biol Cell 2015; 26:3001-12. [PMID: 26157165 PMCID: PMC4551315 DOI: 10.1091/mbc.e14-10-1427] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 06/30/2015] [Indexed: 12/15/2022] Open
Abstract
Complementation of a conditional KO of actin-depolymerizing factor (ADF) in Toxoplasma gondii demonstrates that ADF-dependent actin filament disassembly is essential for parasite development but not for cell motility. Furthermore, trans-genera complementation highlights genus-specific coevolution between ADF proteins and their native actins. Proteins of the actin-depolymerizing factor (ADF)/cofilin family have been shown to be crucial for the motility and survival of apicomplexan parasites. However, the mechanisms by which ADF proteins fulfill their function remain poorly understood. In this study, we investigate the comparative activities of ADF proteins from Toxoplasma gondii and Plasmodium falciparum, the human malaria parasite, using a conditional T. gondii ADF-knockout line complemented with ADF variants from either species. We show that P. falciparum ADF1 can fully restore native TgADF activity, demonstrating functional conservation between parasites. Strikingly, mutation of a key basic residue (Lys-72), previously implicated in disassembly in PfADF1, had no detectable phenotypic effect on parasite growth, motility, or development. In contrast, organelle segregation was severely impaired when complementing with a TgADF mutant lacking the corresponding residue (Lys-68). Biochemical analyses of each ADF protein confirmed the reduced ability of lysine mutants to mediate actin depolymerization via filament disassembly although not severing, in contrast to previous reports. These data suggest that actin filament disassembly is essential for apicomplexan parasite development but not for motility, as well as pointing to genus-specific coevolution between ADF proteins and their native actin.
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Affiliation(s)
- Silvia Haase
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Dennis Zimmermann
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637
| | - Maya A Olshina
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Mark Wilkinson
- Department of Life Sciences, Imperial College, London SW7 2AZ, United Kingdom
| | - Fabio Fisher
- Department of Life Sciences, Imperial College, London SW7 2AZ, United Kingdom
| | - Yan Hong Tan
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Rebecca J Stewart
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Christopher J Tonkin
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Wilson Wong
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637
| | - Jake Baum
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia Department of Life Sciences, Imperial College, London SW7 2AZ, United Kingdom
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18
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Hliscs M, Millet C, Dixon MW, Siden-Kiamos I, McMillan P, Tilley L. Organization and function of an actin cytoskeleton inPlasmodium falciparumgametocytes. Cell Microbiol 2014; 17:207-25. [DOI: 10.1111/cmi.12359] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 08/16/2014] [Accepted: 08/19/2014] [Indexed: 01/05/2023]
Affiliation(s)
- Marion Hliscs
- Department of Biochemistry and Molecular Biology; Bio21 Molecular Science and Biotechnology Institute; Melbourne Vic. 3010 Australia
- Australian Research Council Centre of Excellence for Coherent X-ray Science; The University of Melbourne; Melbourne Vic. 3010 Australia
- School of Botany; The University of Melbourne; Melbourne Vic. 3010 Australia
| | - Coralie Millet
- Department of Biochemistry and Molecular Biology; Bio21 Molecular Science and Biotechnology Institute; Melbourne Vic. 3010 Australia
- Australian Research Council Centre of Excellence for Coherent X-ray Science; The University of Melbourne; Melbourne Vic. 3010 Australia
| | - Matthew W. Dixon
- Department of Biochemistry and Molecular Biology; Bio21 Molecular Science and Biotechnology Institute; Melbourne Vic. 3010 Australia
- Australian Research Council Centre of Excellence for Coherent X-ray Science; The University of Melbourne; Melbourne Vic. 3010 Australia
| | - Inga Siden-Kiamos
- Institute of Molecular Biology and Biotechnology; Foundation for Research and Technology; Hellas, 700 13 Heraklion Crete Greece
| | - Paul McMillan
- Department of Biochemistry and Molecular Biology; Bio21 Molecular Science and Biotechnology Institute; Melbourne Vic. 3010 Australia
- The Biological Optical Microscopy Platform; The University of Melbourne; Melbourne Vic. 3010 Australia
| | - Leann Tilley
- Department of Biochemistry and Molecular Biology; Bio21 Molecular Science and Biotechnology Institute; Melbourne Vic. 3010 Australia
- Australian Research Council Centre of Excellence for Coherent X-ray Science; The University of Melbourne; Melbourne Vic. 3010 Australia
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19
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Ma C, Diraviyam K, Maier ME, Sept D, Sibley LD. Synthetic chondramide A analogues stabilize filamentous actin and block invasion by Toxoplasma gondii. JOURNAL OF NATURAL PRODUCTS 2013; 76:1565-1572. [PMID: 24020843 PMCID: PMC3787807 DOI: 10.1021/np400196w] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Indexed: 05/31/2023]
Abstract
Apicomplexan parasites such as Toxoplasma gondii rely on actin-based motility to cross biological barriers and invade host cells. Key structural and biochemical differences in host and parasite actins make this an attractive target for small-molecule inhibitors. Here we took advantage of recent advances in the synthesis of cyclic depsipeptide compounds that stabilize filamentous actin to test the ability of chondramides to disrupt growth of T. gondii in vitro. Structural modeling of chondramide A (2) binding to an actin filament model revealed variations in the binding site between host and parasite actins. A series of 10 previously synthesized analogues (2b-k) with substitutions in the β-tyrosine moiety blocked parasite growth on host cell monolayers with EC₅₀ values that ranged from 0.3 to 1.3 μM. In vitro polymerization assays using highly purified recombinant actin from T. gondii verified that synthetic and natural product chondramides target the actin cytoskeleton. Consistent with this, chondramide treatment blocked parasite invasion into host cells and was more rapidly effective than pyrimethamine, a standard therapeutic agent. Although the current compounds lack specificity for parasite vs host actin, these studies provide a platform for the future design and synthesis of synthetic cyclic peptide inhibitors that selectively disrupt actin dynamics in parasites.
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Affiliation(s)
- Christopher
I. Ma
- Department
of Molecular Microbiology, Washington University
School of Medicine, St. Louis, Missouri 63110, United States
| | - Karthikeyan Diraviyam
- Department
of Biomedical Engineering and Center for Computational Medicine and
Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Martin E. Maier
- Institut
für Organische Chemie, Universität
Tübingen, 72076 Tübingen, Germany
| | - David Sept
- Department
of Biomedical Engineering and Center for Computational Medicine and
Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - L. David Sibley
- Department
of Molecular Microbiology, Washington University
School of Medicine, St. Louis, Missouri 63110, United States
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20
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Valigurová A, Vaškovicová N, Musilová N, Schrével J. The enigma of eugregarine epicytic folds: where gliding motility originates? Front Zool 2013; 10:57. [PMID: 24053424 PMCID: PMC3849649 DOI: 10.1186/1742-9994-10-57] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Accepted: 08/24/2013] [Indexed: 11/12/2022] Open
Abstract
Background In the past decades, many studies focused on the cell motility of apicomplexan invasive stages as they represent a potential target for chemotherapeutic intervention. Gregarines (Conoidasida, Gregarinasina) are a heterogeneous group that parasitize invertebrates and urochordates, and are thought to be an early branching lineage of Apicomplexa. As characteristic of apicomplexan zoites, gregarines are covered by a complicated pellicle, consisting of the plasma membrane and the closely apposed inner membrane complex, which is associated with a number of cytoskeletal elements. The cell cortex of eugregarines, the epicyte, is more complicated than that of other apicomplexans, as it forms various superficial structures. Results The epicyte of the eugregarines, Gregarina cuneata, G. polymorpha and G. steini, analysed in the present study is organised in longitudinal folds covering the entire cell. In mature trophozoites and gamonts, each epicytic fold exhibits similar ectoplasmic structures and is built up from the plasma membrane, inner membrane complex, 12-nm filaments, rippled dense structures and basal lamina. In addition, rib-like myonemes and an ectoplasmic network are frequently observed. Under experimental conditions, eugregarines showed varied speeds and paths of simple linear gliding. In all three species, actin and myosin were associated with the pellicle, and this actomyosin complex appeared to be restricted to the lateral parts of the epicytic folds. Treatment of living gamonts with jasplakinolide and cytochalasin D confirmed that actin actively participates in gregarine gliding. Contributions to gliding of specific subcellular components are discussed. Conclusions Cell motility in gregarines and other apicomplexans share features in common, i.e. a three-layered pellicle, an actomyosin complex, and the polymerisation of actin during gliding. Although the general architecture and supramolecular organisation of the pellicle is not correlated with gliding rates of eugregarines, an increase in cytoplasmic mucus concentration is correlated. Furthermore, our data suggest that gregarines utilize several mechanisms of cell motility and that this is influenced by environmental conditions.
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Affiliation(s)
- Andrea Valigurová
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic.
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21
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Kühni-Boghenbor K, Ma M, Lemgruber L, Cyrklaff M, Frischknecht F, Gaschen V, Stoffel M, Baumgartner M. Actin-mediated plasma membrane plasticity of the intracellular parasite Theileria annulata. Cell Microbiol 2012; 14:1867-79. [PMID: 22891986 DOI: 10.1111/cmi.12006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 06/22/2012] [Accepted: 08/07/2012] [Indexed: 11/27/2022]
Abstract
Pathogen-host interactions are modulated at multiple levels by both the pathogen and the host cell. Modulation of host cell functions is particularly intriguing in the case of the intracellular Theileria parasite, which resides as a multinucleated schizont free in the cytosol of the host cell. Direct contact between the schizont plasma membrane and the cytoplasm enables the parasite to affect the function of host cell proteins through direct interaction or through the secretion of regulators. Structure and dynamics of the schizont plasma membrane are poorly understood and whether schizont membrane dynamics contribute to parasite propagation is not known. Here we show that the intracellular Theileria schizont can dynamically change its shape by actively extending filamentous membrane protrusions. We found that isolated schizonts bound monomeric tubulin and in vitro polymerized microtubules, and monomeric tubulin polymerized into dense assemblies at the parasite surface. However, we established that isolated Theileria schizonts free of host cell microtubules maintained a lobular morphology and extended filamentous protrusions, demonstrating that host microtubules are dispensable both forthe maintenance of lobular schizont morphology and for the generation of membrane protrusions. These protrusions resemble nanotubes and extend in an actin polymerization-dependent manner; using cryo-electron tomography, we detected thin actin filaments beneath these protrusions, indicating that their extension is driven by schizont actin polymerization. Thus the membrane of the schizont and its underlying actin cytoskeleton possess intrinsic activity for shape control and likely function as a peri-organelle to interact with and manipulate host cell components.
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22
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Delorme-Walker V, Abrivard M, Lagal V, Anderson K, Perazzi A, Gonzalez V, Page C, Chauvet J, Ochoa W, Volkmann N, Hanein D, Tardieux I. Toxofilin upregulates the host cortical actin cytoskeleton dynamics, facilitating Toxoplasma invasion. J Cell Sci 2012; 125:4333-42. [PMID: 22641695 DOI: 10.1242/jcs.103648] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Toxoplasma gondii, a human pathogen and a model apicomplexan parasite, actively and rapidly invades host cells. To initiate invasion, the parasite induces the formation of a parasite-cell junction, and progressively propels itself through the junction, inside a newly formed vacuole that encloses the entering parasite. Little is known about how a parasite that is a few microns in diameter overcomes the host cell cortical actin barrier to achieve the remarkably rapid process of internalization (less than a few seconds). Using correlative light and electron microscopy in conjunction with electron tomography and three-dimensional image analysis we identified that toxofilin, an actin-binding protein, secreted by invading parasites correlates with localized sites of disassembly of the host cell actin meshwork. Moreover, quantitative fluorescence speckle microscopy of cells expressing toxofilin showed that toxofilin regulates actin filament disassembly and turnover. Furthermore, Toxoplasma tachyzoites lacking toxofilin, were found to be impaired in cortical actin disassembly and exhibited delayed invasion kinetics. We propose that toxofilin locally upregulates actin turnover thus increasing depolymerization events at the site of entry that in turn loosens the local host cell actin meshwork, facilitating parasite internalization and vacuole folding.
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Affiliation(s)
- Violaine Delorme-Walker
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA
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23
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Angrisano F, Riglar DT, Sturm A, Volz JC, Delves MJ, Zuccala ES, Turnbull L, Dekiwadia C, Olshina MA, Marapana DS, Wong W, Mollard V, Bradin CH, Tonkin CJ, Gunning PW, Ralph SA, Whitchurch CB, Sinden RE, Cowman AF, McFadden GI, Baum J. Spatial localisation of actin filaments across developmental stages of the malaria parasite. PLoS One 2012; 7:e32188. [PMID: 22389687 PMCID: PMC3289632 DOI: 10.1371/journal.pone.0032188] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Accepted: 01/23/2012] [Indexed: 02/02/2023] Open
Abstract
Actin dynamics have been implicated in a variety of developmental processes during the malaria parasite lifecycle. Parasite motility, in particular, is thought to critically depend on an actomyosin motor located in the outer pellicle of the parasite cell. Efforts to understand the diverse roles actin plays have, however, been hampered by an inability to detect microfilaments under native conditions. To visualise the spatial dynamics of actin we generated a parasite-specific actin antibody that shows preferential recognition of filamentous actin and applied this tool to different lifecycle stages (merozoites, sporozoites and ookinetes) of the human and mouse malaria parasite species Plasmodium falciparum and P. berghei along with tachyzoites from the related apicomplexan parasite Toxoplasma gondii. Actin filament distribution was found associated with three core compartments: the nuclear periphery, pellicular membranes of motile or invasive parasite forms and in a ring-like distribution at the tight junction during merozoite invasion of erythrocytes in both human and mouse malaria parasites. Localisation at the nuclear periphery is consistent with an emerging role of actin in facilitating parasite gene regulation. During invasion, we show that the actin ring at the parasite-host cell tight junction is dependent on dynamic filament turnover. Super-resolution imaging places this ring posterior to, and not concentric with, the junction marker rhoptry neck protein 4. This implies motor force relies on the engagement of dynamic microfilaments at zones of traction, though not necessarily directly through receptor-ligand interactions at sites of adhesion during invasion. Combined, these observations extend current understanding of the diverse roles actin plays in malaria parasite development and apicomplexan cell motility, in particular refining understanding on the linkage of the internal parasite gliding motor with the extra-cellular milieu.
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Affiliation(s)
- Fiona Angrisano
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - David T. Riglar
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Angelika Sturm
- School of Botany University of Melbourne, Parkville, Victoria, Australia
| | - Jennifer C. Volz
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Michael J. Delves
- Department of Biological Sciences, Imperial College of Science, Technology and Medicine, London, United Kingdom
| | - Elizabeth S. Zuccala
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Lynne Turnbull
- The ithree Institute, University of Technology Sydney, Sydney, New South Wales, Australia
| | - Chaitali Dekiwadia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Maya A. Olshina
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Danushka S. Marapana
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Wilson Wong
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Vanessa Mollard
- Department of Biological Sciences, Imperial College of Science, Technology and Medicine, London, United Kingdom
| | - Clare H. Bradin
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Christopher J. Tonkin
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Peter W. Gunning
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Stuart A. Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Cynthia B. Whitchurch
- The ithree Institute, University of Technology Sydney, Sydney, New South Wales, Australia
| | - Robert E. Sinden
- School of Botany University of Melbourne, Parkville, Victoria, Australia
| | - Alan F. Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Geoffrey I. McFadden
- Department of Biological Sciences, Imperial College of Science, Technology and Medicine, London, United Kingdom
| | - Jake Baum
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
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24
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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.
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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
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25
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Montagna GN, Buscaglia CA, Münter S, Goosmann C, Frischknecht F, Brinkmann V, Matuschewski K. Critical role for heat shock protein 20 (HSP20) in migration of malarial sporozoites. J Biol Chem 2011; 287:2410-22. [PMID: 22139844 DOI: 10.1074/jbc.m111.302109] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Plasmodium sporozoites, single cell eukaryotic pathogens, use their own actin/myosin-based motor machinery for life cycle progression, which includes forward locomotion, penetration of cellular barriers, and invasion of target cells. To display fast gliding motility, the parasite uses a high turnover of actin polymerization and adhesion sites. Paradoxically, only a few classic actin regulatory proteins appear to be encoded in the Plasmodium genome. Small heat shock proteins have been associated with cytoskeleton modulation in various biological processes. In this study, we identify HSP20 as a novel player in Plasmodium motility and provide molecular genetics evidence for a critical role of a small heat shock protein in cell traction and motility. We demonstrate that HSP20 ablation profoundly affects sporozoite-substrate adhesion, which translates into aberrant speed and directionality in vitro. Loss of HSP20 function impairs migration in the host, an important sporozoite trait required to find a blood vessel and reach the liver after being deposited in the skin by the mosquito. Our study also shows that fast locomotion of sporozoites is crucial during natural malaria transmission.
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26
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Angrisano F, Delves MJ, Sturm A, Mollard V, McFadden GI, Sinden RE, Baum J. A GFP-actin reporter line to explore microfilament dynamics across the malaria parasite lifecycle. Mol Biochem Parasitol 2011; 182:93-6. [PMID: 22138565 DOI: 10.1016/j.molbiopara.2011.11.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 11/07/2011] [Accepted: 11/15/2011] [Indexed: 11/18/2022]
Abstract
Malaria parasite motility relies on an internal parasite actomyosin motor that, when linked to the host cell substrate, propels motile zoites forward. Despite their key role in this process, attempts to visualize actin microfilaments (F-actin) during motility and under native microscopy conditions have not to date been successful. Towards facilitating their visualization we present here a Plasmodium berghei transgenic line in which a green fluorescent protein (GFP)-actin fusion is constitutively expressed through the lifecycle. Focused investigation of the largest motile form, the insect stage ookinete, demonstrates a large cytosolic pool of actin with no obvious F-actin structures. However, following treatment with the actin filament-stabilizing drug Jasplakinolide, we show evidence for concentration of F-actin dynamics in the parasite pellicle and at polar apices. These observations support current models for gliding motility and establish a cellular tool for further exploration of the diverse roles actin is thought to play throughout parasite development.
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Affiliation(s)
- Fiona Angrisano
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, 3052, Australia
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27
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Sattler JM, Ganter M, Hliscs M, Matuschewski K, Schüler H. Actin regulation in the malaria parasite. Eur J Cell Biol 2011; 90:966-71. [DOI: 10.1016/j.ejcb.2010.11.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 11/22/2010] [Accepted: 11/23/2010] [Indexed: 10/18/2022] Open
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28
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Evolutionarily divergent, unstable filamentous actin is essential for gliding motility in apicomplexan parasites. PLoS Pathog 2011; 7:e1002280. [PMID: 21998582 PMCID: PMC3188518 DOI: 10.1371/journal.ppat.1002280] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 08/17/2011] [Indexed: 01/05/2023] Open
Abstract
Apicomplexan parasites rely on a novel form of actin-based motility called gliding, which depends on parasite actin polymerization, to migrate through their hosts and invade cells. However, parasite actins are divergent both in sequence and function and only form short, unstable filaments in contrast to the stability of conventional actin filaments. The molecular basis for parasite actin filament instability and its relationship to gliding motility remain unresolved. We demonstrate that recombinant Toxoplasma (TgACTI) and Plasmodium (PfACTI and PfACTII) actins polymerized into very short filaments in vitro but were induced to form long, stable filaments by addition of equimolar levels of phalloidin. Parasite actins contain a conserved phalloidin-binding site as determined by molecular modeling and computational docking, yet vary in several residues that are predicted to impact filament stability. In particular, two residues were identified that form intermolecular contacts between different protomers in conventional actin filaments and these residues showed non-conservative differences in apicomplexan parasites. Substitution of divergent residues found in TgACTI with those from mammalian actin resulted in formation of longer, more stable filaments in vitro. Expression of these stabilized actins in T. gondii increased sensitivity to the actin-stabilizing compound jasplakinolide and disrupted normal gliding motility in the absence of treatment. These results identify the molecular basis for short, dynamic filaments in apicomplexan parasites and demonstrate that inherent instability of parasite actin filaments is a critical adaptation for gliding motility.
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29
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Yadav R, Pathak PP, Shukla VK, Jain A, Srivastava S, Tripathi S, Krishna Pulavarti SVSR, Mehta S, Sibley LD, Arora A. Solution structure and dynamics of ADF from Toxoplasma gondii. J Struct Biol 2011; 176:97-111. [PMID: 21820516 DOI: 10.1016/j.jsb.2011.07.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 07/13/2011] [Accepted: 07/19/2011] [Indexed: 12/01/2022]
Abstract
Toxoplasma gondii ADF (TgADF) belongs to a functional subtype characterized by strong G-actin sequestering activity and low F-actin severing activity. Among the characterized ADF/cofilin proteins, TgADF has the shortest length and is missing a C-terminal helix implicated in F-actin binding. In order to understand its characteristic properties, we have determined the solution structure of TgADF and studied its backbone dynamics from ¹⁵N-relaxation measurements. TgADF has conserved ADF/cofilin fold consisting of a central mixed β-sheet comprised of six β-strands that are partially surrounded by three α-helices and a C-terminal helical turn. The high G-actin sequestering activity of TgADF relies on highly structurally and dynamically optimized interactions between G-actin and G-actin binding surface of TgADF. The equilibrium dissociation constant for TgADF and rabbit muscle G-actin was 23.81 nM, as measured by ITC, which reflects very strong affinity of TgADF and G-actin interactions. The F-actin binding site of TgADF is partially formed, with a shortened F-loop that does not project out of the ellipsoid structure and a C-terminal helical turn in place of the C-terminal helix α4. Yet, it is more rigid than the F-actin binding site of Leishmania donovani cofilin. Experimental observations and structural features do not support the interaction of PIP2 with TgADF, and PIP2 does not affect the interaction of TgADF with G-actin. Overall, this study suggests that conformational flexibility of G-actin binding sites enhances the affinity of TgADF for G-actin, while conformational rigidity of F-actin binding sites of conventional ADF/cofilins is necessary for stable binding to F-actin.
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Affiliation(s)
- Rahul Yadav
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow 226001, India
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30
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Mehta S, Sibley LD. Actin depolymerizing factor controls actin turnover and gliding motility in Toxoplasma gondii. Mol Biol Cell 2011; 22:1290-9. [PMID: 21346192 PMCID: PMC3078074 DOI: 10.1091/mbc.e10-12-0939] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Actin-based motility is vital for host cell invasion by protozoan parasites such as Toxoplasma, which provides a model for studying actin-based motility in parasites. Our study reveals that, in addition to intrinsic differences in actin dynamics, regulatory proteins like actin depolymerizing factor are required to regulate this process in vivo. Apicomplexan parasites rely on actin-based gliding motility to move across the substratum, cross biological barriers, and invade their host cells. Gliding motility depends on polymerization of parasite actin filaments, yet ∼98% of actin is nonfilamentous in resting parasites. Previous studies suggest that the lack of actin filaments in the parasite is due to inherent instability, leaving uncertain the role of actin-binding proteins in controlling dynamics. We have previously shown that the single allele of Toxoplasma gondii actin depolymerizing factor (TgADF) has strong actin monomer–sequestering and weak filament-severing activities in vitro. Here we used a conditional knockout strategy to investigate the role of TgADF in vivo. Suppression of TgADF led to accumulation of actin-rich filaments that were detected by immunofluorescence and electron microscopy. Parasites deficient in TgADF showed reduced speed of motility, increased aberrant patterns of motion, and inhibition of sustained helical gliding. Lack of TgADF also led to severe defects in entry and egress from host cells, thus blocking infection in vitro. These studies establish that the absence of stable actin structures in the parasite are not simply the result of intrinsic instability, but that TgADF is required for the rapid turnover of parasite actin filaments, gliding motility, and cell invasion.
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Affiliation(s)
- Simren Mehta
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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31
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Schmitz S, Schaap IAT, Kleinjung J, Harder S, Grainger M, Calder L, Rosenthal PB, Holder AA, Veigel C. Malaria parasite actin polymerization and filament structure. J Biol Chem 2010; 285:36577-85. [PMID: 20826799 PMCID: PMC2978586 DOI: 10.1074/jbc.m110.142638] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 09/02/2010] [Indexed: 11/06/2022] Open
Abstract
A novel form of acto-myosin regulation has been proposed in which polymerization of new actin filaments regulates motility of parasites of the apicomplexan class of protozoa. In vivo and in vitro parasite F-actin is very short and unstable, but the structural basis and details of filament dynamics remain unknown. Here, we show that long actin filaments can be obtained by polymerizing unlabeled rabbit skeletal actin (RS-actin) onto both ends of the short rhodamine-phalloidin-stabilized Plasmodium falciparum actin I (Pf-actin) filaments. Following annealing, hybrid filaments of micron length and "zebra-striped" appearance are observed by fluorescence microscopy that are stable enough to move over myosin class II motors in a gliding filament assay. Using negative stain electron microscopy we find that pure Pf-actin stabilized by jasplakinolide (JAS) also forms long filaments, indistinguishable in length from RS-actin filaments, and long enough to be characterized structurally. To compare structures in near physiological conditions in aqueous solution we imaged Pf-actin and RS-actin filaments by atomic force microscopy (AFM). We found the monomer stacking to be distinctly different for Pf-actin compared with RS-actin, such that the pitch of the double helix of Pf-actin filaments was 10% larger. Our results can be explained by a rotational angle between subunits that is larger in the parasite compared with RS-actin. Modeling of the AFM data using high-resolution actin filament models supports our interpretation of the data. The structural differences reported here may be a consequence of weaker inter- and intra-strand contacts, and may be critical for differences in filament dynamics and for regulation of parasite motility.
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Affiliation(s)
| | | | | | - Simone Harder
- From the Division of Physical Biochemistry
- the Division of Parasitology, National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
| | - Munira Grainger
- the Division of Parasitology, National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
| | | | | | - Anthony A. Holder
- the Division of Parasitology, National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
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32
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Kucera K, Koblansky AA, Saunders LP, Frederick KB, De La Cruz EM, Ghosh S, Modis Y. Structure-based analysis of Toxoplasma gondii profilin: a parasite-specific motif is required for recognition by Toll-like receptor 11. J Mol Biol 2010; 403:616-29. [PMID: 20851125 DOI: 10.1016/j.jmb.2010.09.022] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 09/02/2010] [Accepted: 09/08/2010] [Indexed: 11/19/2022]
Abstract
Profilins promote actin polymerization by exchanging ADP for ATP on monomeric actin and delivering ATP-actin to growing filament barbed ends. Apicomplexan protozoa such as Toxoplasma gondii invade host cells using an actin-dependent gliding motility. Toll-like receptor (TLR) 11 generates an innate immune response upon sensing T. gondii profilin (TgPRF). The crystal structure of TgPRF reveals a parasite-specific surface motif consisting of an acidic loop, followed by a long β-hairpin. A series of structure-based profilin mutants show that TLR11 recognition of the acidic loop is responsible for most of the interleukin (IL)-12 secretion response to TgPRF in peritoneal macrophages. Deletion of both the acidic loop and the β-hairpin completely abrogates IL-12 secretion. Insertion of the T. gondii acidic loop and β-hairpin into yeast profilin is sufficient to generate TLR11-dependent signaling. Substitution of the acidic loop in TgPRF with the homologous loop from the apicomplexan parasite Cryptosporidium parvum does not affect TLR11-dependent IL-12 secretion, while substitution with the acidic loop from Plasmodium falciparum results in reduced but significant IL-12 secretion. We conclude that the parasite-specific motif in TgPRF is the key molecular pattern recognized by TLR11. Unlike other profilins, TgPRF slows nucleotide exchange on monomeric rabbit actin and binds rabbit actin weakly. The putative TgPRF actin-binding surface includes the β-hairpin and diverges widely from the actin-binding surfaces of vertebrate profilins.
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Affiliation(s)
- Kaury Kucera
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06520, USA
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33
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Holzinger A. Jasplakinolide: an actin-specific reagent that promotes actin polymerization. Methods Mol Biol 2010; 586:71-87. [PMID: 19768425 DOI: 10.1007/978-1-60761-376-3_4] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Jasplakinolide, a cyclo-depsipeptide is a commonly used actin filament polymerizing and stabilizing drug. The substance has originally been isolated from a marine sponge, and can now be synthesized and has become commercially available. This, together with the benefit that jasplakinolide is membrane permeable has made it a commonly used tool in cell biology, when actin filament stabilization or polymerization has to be achieved. This may either be the case in studies on morphogenesis, motility, organelle movement, or when apoptosis has to be induced. Its use as a potent anticancer drug is discussed. The direct action on actin filaments may have further consequences in golgi body and membrane raft protein organization. In this chapter, the visualization of jasplaklinolide effects by different fluorescent and transmission electron microscopic methods is described. As competitive binding capacities of jasplakinolide and phalloidin make the detection of actin filaments by fluorescently labeled phalloidin problematic, alternatives are given here.
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Affiliation(s)
- Andreas Holzinger
- Institute of Botany, Department of Physiology and Cell Physiology, University of Innsbruck, Innsbruck, Austria
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34
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Andavan GSB, Lemmens-Gruber R. Cyclodepsipeptides from marine sponges: natural agents for drug research. Mar Drugs 2010; 8:810-34. [PMID: 20411126 PMCID: PMC2857363 DOI: 10.3390/md8030810] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 03/04/2010] [Accepted: 03/19/2010] [Indexed: 11/24/2022] Open
Abstract
A number of natural products from marine sponges, such as cyclodepsipeptides, have been identified. The structural characteristics of this family of cyclic peptides include various unusual amino acid residues and unique N-terminal polyketide-derived moieties. Papuamides are representatives of a class of marine sponge derived cyclic depsipeptides, including callipeltin A, celebesides A and B, homophymine A, mirabamides, microspinosamide, neamphamide A and theopapuamides. They are thought to have cytoprotective activity against HIV-1 in vitro by inhibiting viral entry. Jasplakinolide, a representative member of marine sponge-derived cyclodepsipeptides that include arenastatin A, geodiamolides, homophymines, spongidepsin and theopapuamides, is a potent inducer of actin polymerization in vitro. Although actin dynamics is essential for tumor metasasis, no actin targeting drugs have been used in clinical trials due to their severe cytotoxicity. Nonetheless, the actin cytoskeleton remains a potential target for anti-cancer drug development. These features imply the use of cyclodepsipeptides as molecular models in drug research.
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Affiliation(s)
| | - Rosa Lemmens-Gruber
- * Author to whom correspondence should be addressed; E-Mail:
; Tel.: +43-1-4277-55325; Fax: +43-1-4277-9553
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35
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Kudryashev M, Lepper S, Baumeister W, Cyrklaff M, Frischknecht F. Geometric constrains for detecting short actin filaments by cryogenic electron tomography. PMC BIOPHYSICS 2010; 3:6. [PMID: 20214767 PMCID: PMC2844354 DOI: 10.1186/1757-5036-3-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Accepted: 03/05/2010] [Indexed: 01/30/2023]
Abstract
Polymerization of actin into filaments can push membranes forming extensions like filopodia or lamellipodia, which are important during processes such as cell motility and phagocytosis. Similarly, small organelles or pathogens can be moved by actin polymerization. Such actin filaments can be arranged in different patterns and are usually hundreds of nanometers in length as revealed by various electron microscopy approaches. Much shorter actin filaments are involved in the motility of apicomplexan parasites. However, these short filaments have to date not been visualized in intact cells. Here, we investigated Plasmodium sporozoites, the motile forms of the malaria parasite that are transmitted by the mosquito, using cryogenic electron tomography. We detected filopodia-like extensions of the plasma membrane and observed filamentous structures in the supra-alveolar space underneath the plasma membrane. However, these filaments could not be unambiguously assigned as actin filaments. In silico simulations of EM data collection and tomographic reconstruction identify the limits in revealing the filaments due to their length, concentration and orientation. PACS Codes: 87.64.Ee
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Affiliation(s)
- Mikhail Kudryashev
- Parasitology, Department of Infectious Diseases, University of Heidelberg Medical School, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany.
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36
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TgMORN1 is a key organizer for the basal complex of Toxoplasma gondii. PLoS Pathog 2010; 6:e1000754. [PMID: 20140195 PMCID: PMC2816694 DOI: 10.1371/journal.ppat.1000754] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 01/06/2010] [Indexed: 01/02/2023] Open
Abstract
Toxoplasma gondii is a leading cause of congenital birth defects, as well as a cause for ocular and neurological diseases in humans. Its cytoskeleton is essential for parasite replication and invasion and contains many unique structures that are potential drug targets. Therefore, the biogenesis of the cytoskeletal structure of T. gondii is not only important for its pathogenesis, but also of interest to cell biology in general. Previously, we and others identified a new T. gondii cytoskeletal protein, TgMORN1, which is recruited to the basal complex at the very beginning of daughter formation. However, its function remained largely unknown. In this study, we generated a knock-out mutant of TgMORN1 (ΔTgMORN1) using a Cre-LoxP based approach. We found that the structure of the basal complex was grossly affected in ΔTgMORN1 parasites, which also displayed defects in cytokinesis. Moreover, ΔTgMORN1 parasites showed significant growth impairment in vitro, and this translated into greatly attenuated virulence in mice. Therefore, our results demonstrate that TgMORN1 is required for maintaining the structural integrity of the parasite posterior end, and provide direct evidence that cytoskeleton integrity is essential for parasite virulence and pathogenesis. The disease toxoplasmosis is the result of uncontrolled growth and proliferation of the intracellular parasite Toxoplasma gondii, which is pathogenic for most warm-blooded animals. If growth of the parasite is blocked, then it does not cause disease, even though it may persist in the host as a chronic infection. Proper assembly of the cytoskeleton of T. gondii is known to be essential for its growth, and consequently required for virulence. In this study, we investigated the function of a novel cytoskeletal protein, TgMORN1, in T. gondii. TgMORN1 is a major component of the basal complex, a novel cytoskeletal assembly located at the posterior end of the parasite. We found that TgMORN1 is required for maintaining the structural integrity of the parasite posterior end and is important for ensuring successful separation of daughters at late stage of parasite replication. In addition, infection with parasites deficient in TgMORN1 not only failed to kill mice but also provided protective immunity against a lethal challenge infection, indicating the importance of TgMORN1 in T. gondii growth both in vitro and in vivo.
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37
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38
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Mehta S, Sibley LD. Toxoplasma gondii actin depolymerizing factor acts primarily to sequester G-actin. J Biol Chem 2009; 285:6835-47. [PMID: 20042603 DOI: 10.1074/jbc.m109.068155] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Toxoplasma gondii is a protozoan parasite belonging to the phylum Apicomplexa. Parasites in this phylum utilize a unique process of motility termed gliding, which is dependent on parasite actin filaments. Surprisingly, 98% of parasite actin is maintained as G-actin, suggesting that filaments are rapidly assembled and turned over. Little is known about the regulated disassembly of filaments in the Apicomplexa. In higher eukaryotes, the related actin depolymerizing factor (ADF) and cofilin proteins are essential regulators of actin filament turnover. ADF is one of the few actin-binding proteins conserved in apicomplexan parasites. In this study we examined the mechanism by which T. gondii ADF (TgADF) regulates actin filament turnover. Unlike other members of the ADF/cofilin (AC) family, apicomplexan ADFs lack key F-actin binding sites. Surprisingly, this promotes their enhanced disassembly of actin filaments. Restoration of the C-terminal F-actin binding site to TgADF stabilized its interaction with filaments but reduced its net filament disassembly activity. Analysis of severing activity revealed that TgADF is a weak severing protein, requiring much higher concentrations than typical AC proteins. Investigation of TgADF interaction with T. gondii actin (TgACT) revealed that TgADF disassembled short TgACT oligomers. Kinetic and steady-state polymerization assays demonstrated that TgADF has strong monomer-sequestering activity, inhibiting TgACT polymerization at very low concentrations. Collectively these data indicate that TgADF promoted the efficient turnover of actin filaments via weak severing of filaments and strong sequestering of monomers. This suggests a dual role for TgADF in maintaining high G-actin concentrations and effecting rapid filament turnover.
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Affiliation(s)
- Simren Mehta
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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39
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Frénal K, Soldati-Favre D. Role of the parasite and host cytoskeleton in apicomplexa parasitism. Cell Host Microbe 2009; 5:602-11. [PMID: 19527887 DOI: 10.1016/j.chom.2009.05.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 05/22/2009] [Accepted: 05/28/2009] [Indexed: 11/25/2022]
Abstract
The phylum Apicomplexa includes a large and diverse group of obligate intracellular parasites that rely on actomyosin-based motility to migrate, enter host cells, and egress from infected cells. To ensure their intracellular survival and replication, the apicomplexans have evolved sophisticated strategies for subversion of the host cytoskeleton. Given the properties in common between the host and parasite cytoskeleton, dissecting their individual contribution to the establishment of parasitic infection has been challenging. Nevertheless, recent studies have provided new insights into the mechanisms by which parasites subvert the dynamic properties of host actin and tubulin to promote their entry, development, and egress.
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Affiliation(s)
- Karine Frénal
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, 1 rue Michel-Servet, 1211 Geneva 4, Switzerland.
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40
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Heintzelman MB, Mateer MJ. GpMyoF, a WD40 repeat-containing myosin associated with the myonemes of Gregarina polymorpha. J Parasitol 2008; 94:158-68. [PMID: 18372636 DOI: 10.1645/ge-1339.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
This study presents the first characterization of a WD40 repeat-containing myosin identified in the apicomplexan parasite Gregarina polymorpha. This 222.7 kDa myosin, GpMyoF, contains a canonical myosin motor domain, a neck domain with 6 IQ motifs, a tail domain containing short regions of predicted coiled-coil structure, and, most notably, multiple WD40 repeats at the C-terminus. In other proteins such repeats assemble into a beta-propeller structure implicated in mediating protein-protein interactions. Confocal microscopy suggests that GpMyoF is localized to the annular myonemes that gird the parasite cortex. Extraction studies indicate that this myosin shows an unusually tight association with the cytoskeletal fraction and can be solubilized only by treatment with high pH (11.5) or the anionic detergent sarkosyl. This novel myosin and its homologs, which have been identified in several related genera, appear to be unique to the Apicomplexa and represent the only myosins known to contain the WD40 domain. The function of this myosin in G. polymorpha or any of the other apicomplexan parasites remains uncertain.
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Affiliation(s)
- Matthew B Heintzelman
- Department of Biology, Program in Cell Biology and Biochemistry, Bucknell University, Lewisburg, Pennsylvania 17837, USA.
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Plattner F, Yarovinsky F, Romero S, Didry D, Carlier MF, Sher A, Soldati-Favre D. Toxoplasma profilin is essential for host cell invasion and TLR11-dependent induction of an interleukin-12 response. Cell Host Microbe 2008; 3:77-87. [PMID: 18312842 DOI: 10.1016/j.chom.2008.01.001] [Citation(s) in RCA: 263] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2007] [Revised: 11/14/2007] [Accepted: 01/08/2008] [Indexed: 11/24/2022]
Abstract
Apicomplexan parasites exhibit actin-dependent gliding motility that is essential for migration across biological barriers and host cell invasion. Profilins are key contributors to actin polymerization, and the parasite Toxoplasma gondii possesses a profilin-like protein that is recognized by Toll-like receptor TLR11 in the host innate immune system. Here, we show by conditional disruption of the corresponding gene that T.gondii profilin, while not required for intracellular growth, is indispensable for gliding motility, host cell invasion, active egress from host cells, and virulence in mice. Furthermore, parasites lacking profilin are unable to induce TLR11-dependent production in vitro and in vivo of the defensive host cytokine interleukin-12. Thus, profilin is an essential element of two aspects of T. gondii infection. Like bacterial flagellin, profilin plays a role in motility while serving as a microbial ligand recognized by the host innate immune system.
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Affiliation(s)
- Fabienne Plattner
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, 1 rue Michel-Servet, 1211 Geneva 4, Switzerland
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A Malaria Parasite Formin Regulates Actin Polymerization and Localizes to the Parasite-Erythrocyte Moving Junction during Invasion. Cell Host Microbe 2008; 3:188-98. [DOI: 10.1016/j.chom.2008.02.006] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 01/22/2008] [Accepted: 02/18/2008] [Indexed: 11/21/2022]
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Schüler H, Matuschewski K. Regulation of apicomplexan microfilament dynamics by a minimal set of actin-binding proteins. Traffic 2006; 7:1433-9. [PMID: 17010119 DOI: 10.1111/j.1600-0854.2006.00484.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Efficient and rapid host cell invasion is a prerequisite for an intracellular parasitic life style. Pathogens typically induce receptor-mediated endocytosis and hijack the force-transducing system of a host cell to gain access to a replication-competent niche. In striking contrast, apicomplexan parasites such as Plasmodium, the causative agent of malaria, and the human and animal pathogens Toxoplasma and Cryptosporidium employ their own actomyosin motor machinery to propel themselves into prospective host cells. Understanding the regulation and dynamics of actin-based motility of these parasites is therefore central to understanding their pathogenesis. The parasite genomes harbour surprisingly few potential actin-regulatory proteins indicating that a basic repertoire meets the requirements to regulate actin dynamics. In this article, we summarize our current knowledge of Plasmodium microfilament dynamics and describe its potential players.
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Affiliation(s)
- Herwig Schüler
- Max Delbrück Center for Molecular Medicine, Berlin 13125, Germany.
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Siden-Kiamos I, Pinder JC, Louis C. Involvement of actin and myosins in Plasmodium berghei ookinete motility. Mol Biochem Parasitol 2006; 150:308-17. [PMID: 17028009 DOI: 10.1016/j.molbiopara.2006.09.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Revised: 09/04/2006] [Accepted: 09/04/2006] [Indexed: 11/27/2022]
Abstract
Ookinetes of the genus Plasmodium are motile, invasive cells that develop in the mosquito midgut following ingestion of a parasite-infected blood meal. We show here that ookinetes display gliding motility on glass slides in the presence of insect cells. Moreover, in addition to stationary "flexing" and "twirling" of the cells, two distinct types of movements occur: productive forward translocational motility in straight segment that progresses with an average speed of approximately 6mum/min and rotational motility, which does not lead to forward translocation. Locomotion is reduced by treatment with butanedione monoxime, an inhibitor of myosin ATPase, and by three different actin inhibitors. We also studied the expression during ookinete development of genes encoding actin and two small class XIV myosins, PbMyoA, and PbMyoB. Western immunoblots revealed that PbMyoA is only present in fully mature ookinetes, whilst the other two proteins are additionally expressed in gametocytes and zygotes. Immunofluorescence experiments reveal that MyoA and actin co-localize in the apical tip of the parasite whereas MyoB displays a punctate pattern of expression around the entire cell periphery. Following treatment with jasplakinolide, the apparent level of detectable actin appears to substantially increase and becomes concentrated in a discrete area in the basal pole of the ookinete.
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Affiliation(s)
- Inga Siden-Kiamos
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Vassilika Vouton, P.O. Box 1385, 71110 Heraklion, Crete, Greece
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Baum J, Papenfuss AT, Baum B, Speed TP, Cowman AF. Regulation of apicomplexan actin-based motility. Nat Rev Microbiol 2006; 4:621-8. [PMID: 16845432 DOI: 10.1038/nrmicro1465] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Apicomplexan parasites are an ancient group of protozoan parasites that includes several significant pathogens of humans and animals. To target and invade host cells they use a unique form of actin-based motility, called gliding motility. At the centre of the molecular motor that underlies this unique mode of locomotion are short, highly dynamic actin filaments. Recent molecular work, along with the availability of completed genomes for several Apicomplexa, has highlighted unique features of parasite actin and its regulation - features that might provide new ways to block motility and, consequently, prevent infection and disease.
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Affiliation(s)
- Jake Baum
- Division of Infection and Immunity, The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria 3050, Australia
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Heintzelman MB. Cellular and Molecular Mechanics of Gliding Locomotion in Eukaryotes. INTERNATIONAL REVIEW OF CYTOLOGY 2006; 251:79-129. [PMID: 16939778 DOI: 10.1016/s0074-7696(06)51003-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Gliding is a form of substrate-dependent cell locomotion exploited by a variety of disparate cell types. Cells may glide at rates well in excess of 1 microm/sec and do so without the gross distortion of cellular form typical of amoeboid crawling. In the absence of a discrete locomotory organelle, gliding depends upon an assemblage of molecules that links cytoplasmic motor proteins to the cell membrane and thence to the appropriate substrate. Gliding has been most thoroughly studied in the apicomplexan parasites, including Plasmodium and Toxoplasma, which employ a unique assortment of proteins dubbed the glideosome, at the heart of which is a class XIV myosin motor. Actin and myosin also drive the gliding locomotion of raphid diatoms (Bacillariophyceae) as well as the intriguing form of gliding displayed by the spindle-shaped cells of the primitive colonial protist Labyrinthula. Chlamydomonas and other flagellated protists are also able to abandon their more familiar swimming locomotion for gliding, during which time they recruit a motility apparatus independent of that driving flagellar beating.
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Affiliation(s)
- Matthew B Heintzelman
- Department of Biology, Program in Cell Biology and Biochemistry, Bucknell University, Lewisburg, PA 17837, USA
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Sahoo N, Beatty W, Heuser J, Sept D, Sibley LD. Unusual kinetic and structural properties control rapid assembly and turnover of actin in the parasite Toxoplasma gondii. Mol Biol Cell 2005; 17:895-906. [PMID: 16319175 PMCID: PMC1356598 DOI: 10.1091/mbc.e05-06-0512] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Toxoplasma is a protozoan parasite in the phylum Apicomplexa, which contains a number of medically important parasites that rely on a highly unusual form of motility termed gliding to actively penetrate their host cells. Parasite actin filaments regulate gliding motility, yet paradoxically filamentous actin is rarely detected in these parasites. To investigate the kinetics of this unusual parasite actin, we expressed TgACT1 in baculovirus and purified it to homogeneity. Biochemical analysis showed that Toxoplasma actin (TgACT1) rapidly polymerized into filaments at a critical concentration that was 3-4-fold lower than conventional actins, yet it failed to copolymerize with mammalian actin. Electron microscopic analysis revealed that TgACT1 filaments were 10 times shorter and less stable than rabbit actin. Phylogenetic comparison of actins revealed a limited number of apicomplexan-specific residues that likely govern the unusual behavior of parasite actin. Molecular modeling identified several key alterations that affect interactions between monomers and that are predicted to destabilize filaments. Our findings suggest that conserved molecular differences in parasite actin favor rapid cycles of assembly and disassembly that govern the unusual form of gliding motility utilized by apicomplexans.
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Affiliation(s)
- Nivedita Sahoo
- Department of Molecular Microbiology, Center for Infectious Diseases, Washington University School of Medicine, St. Louis, MO 63110, USA
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Wetzel DM, Schmidt J, Kuhlenschmidt MS, Dubey JP, Sibley LD. Gliding motility leads to active cellular invasion by Cryptosporidium parvum sporozoites. Infect Immun 2005; 73:5379-87. [PMID: 16113253 PMCID: PMC1231075 DOI: 10.1128/iai.73.9.5379-5387.2005] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We examined gliding motility and cell invasion by an early-branching apicomplexan, Cryptosporidium parvum, which causes diarrheal disease in humans and animals. Real-time video microscopy demonstrated that C. parvum sporozoites undergo circular and helical gliding, two of the three stereotypical movements exhibited by Toxoplasma gondii tachyzoites. C. parvum sporozoites moved more rapidly than T. gondii sporozoites, which showed the same rates of motility as tachyzoites. Motility by C. parvum sporozoites was prevented by latrunculin B and cytochalasin D, drugs that depolymerize the parasite actin cytoskeleton, and by the myosin inhibitor 2,3-butanedione monoxime. Imaging of the initial events in cell entry by Cryptosporidium revealed that invasion occurs rapidly; however, the parasite does not enter deep into the cytosol but rather remains at the cell surface in a membrane-bound compartment. Invasion did not stimulate rearrangement of the host cell cytoskeleton and was inhibited by cytochalasin D, even in host cells that were resistant to the drug. Our studies demonstrate that C. parvum relies on a conserved actin-myosin motor for motility and active penetration of its host cell, thus establishing that this is a widely conserved feature of the Apicomplexa.
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Affiliation(s)
- Dawn M Wetzel
- Department of Molecular Microbiology, Campus Box 8230, Washington University School of Medicine, St. Louis, MO 63110, USA
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Canton DA, Litchfield DW. The shape of things to come: an emerging role for protein kinase CK2 in the regulation of cell morphology and the cytoskeleton. Cell Signal 2005; 18:267-75. [PMID: 16126370 DOI: 10.1016/j.cellsig.2005.07.008] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2005] [Revised: 07/04/2005] [Accepted: 07/18/2005] [Indexed: 01/24/2023]
Abstract
Protein kinase CK2 is a highly conserved, pleiotropic, protein serine/threonine kinase that is essential for life in eukaryotes. CK2 has been implicated in diverse cellular processes such as cell cycle regulation, circadian rhythms, apoptosis, transformation and tumorigenesis. In addition, there is increasing evidence that CK2 is involved in the maintenance of cell morphology and cell polarity, and in the regulation of the actin and tubulin cytoskeletons. Accordingly, this review will highlight published evidence in experimental models ranging from yeast to mammals documenting the emerging roles of protein kinase CK2 in the regulation of cell polarity, cell morphology and the cytoskeleton.
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Affiliation(s)
- David A Canton
- Regulatory Biology and Functional Genomics Group, Siebens-Drake Medical Research Institute, Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A 5C1
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Cárdenas L, Lovy-Wheeler A, Wilsen KL, Hepler PK. Actin polymerization promotes the reversal of streaming in the apex of pollen tubes. ACTA ACUST UNITED AC 2005; 61:112-27. [PMID: 15849722 DOI: 10.1002/cm.20068] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Actin polymerization is important in the control of pollen tube growth. Thus, treatment of pollen tubes with low concentrations of latrunculin B (Lat-B), which inhibits actin polymerization, permits streaming but reversibly blocks oscillatory growth. In the current study, we employ Jasplakinolide (Jas), a sponge cyclodepsipeptide that stabilizes actin microfilaments and promotes polymerization. Uniquely, Jas (2 microM) blocks streaming in the shank of the tube, but induces the formation of a toroidal-shaped domain in the swollen apex, of which longitudinal optical sections exhibit circles of motion. The polarity of this rotary motion is identical to that of reverse fountain motility in control pollen tubes, with the forward direction occurring at the edge of the cell and the rearward direction in the cell interior. Support for the idea that actin polymerization in the apical domain contributes to the formation of this rotary motility activity derives from the appearance therein of aggregates and flared cables of F-actin, using immunofluorescence, and by the reduction in G-actin as indicated with fluorescent DNAse. In addition, Jas reduces the tip-focused Ca2+ gradient. However, the alkaline band appears in the swollen apex and is spatially localized with the reverse fountain streaming activity. Taken together, our results support the idea that actin polymerization promotes reversal of streaming in the apex of the lily pollen tube.
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Affiliation(s)
- Luis Cárdenas
- Biology Department, and the Plant Biology Graduate Program, Morrill Science Center, University of Massachusetts, Amherst, USA.
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