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Zhu W, Li J, Pappoe F, Shen J, Yu L. Strategies Developed by Toxoplasma gondii to Survive in the Host. Front Microbiol 2019; 10:899. [PMID: 31080445 PMCID: PMC6497798 DOI: 10.3389/fmicb.2019.00899] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 04/09/2019] [Indexed: 12/21/2022] Open
Abstract
One of the most successful intracellular parasites, Toxoplasma gondii has developed several strategies to avoid destruction by the host. These include approaches such as rapid and efficient cell invasion to avoid phagocytic engulfment, negative regulation of the canonical CD40-CD40L-mediated autophagy pathway, impairment of the noncanonical IFN-γ-dependent autophagy pathway, and modulation of host cell survival and death to obtain lifelong parasite survival. Different virulent strains have even evolved different ways to cope with and evade destruction by the host. This review aims to illustrate every aspect of the game between the host and Toxoplasma during the process of infection. A better understanding of all aspects of the battle between Toxoplasma and its hosts will be useful for the development of better strategies and drugs to control the parasite.
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Affiliation(s)
- Wanbo Zhu
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, China.,Graduate School of Affiliated Anhui Provincial Hospital, Anhui Medical University, Hefei, China
| | - Jingyang Li
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, China.,The Clinical Laboratory of the Third People's Hospital of Heifei, Hefei, China
| | - Faustina Pappoe
- Department of Microbiology and Immunology, School of Medical Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Jilong Shen
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, China
| | - Li Yu
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, China
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52
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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: 53] [Impact Index Per Article: 10.6] [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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Jenwithisuk R, Kangwanrangsan N, Tachibana M, Thongkukiatkul A, Otsuki H, Sattabongkot J, Tsuboi T, Torii M, Ishino T. Identification of a PH domain-containing protein which is localized to crystalloid bodies of Plasmodium ookinetes. Malar J 2018; 17:466. [PMID: 30545367 PMCID: PMC6291999 DOI: 10.1186/s12936-018-2617-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 12/06/2018] [Indexed: 11/30/2022] Open
Abstract
Background For the success of the malaria control and eradication programme it is essential to reduce parasite transmission by mosquito vectors. In the midguts of mosquitoes fed with parasite-infected blood, sexual-stage parasites fertilize to develop into motile ookinetes that traverse midgut epithelial cells and reside adjacent the basal lamina. Therefore, the ookinete is a promising target of transmission-blocking vaccines to break the parasite lifecycle in mosquito vectors. However, the molecular mechanisms of ookinete formation and invasion of epithelial cells have not been fully elucidated. A unique structure called the crystalloid body has been identified in the ookinete cytoplasm by electron microscopy, but its biological functions remain unclear. Methods A recombinant protein of a novel molecule, designated as crystalloid body specific PH domain-containing protein of Plasmodium yoelii (PyCryPH), was synthesized using a wheat germ cell-free system. Specific rabbit antibodies against PyCryPH were obtained to characterize the expression and localization of PyCryPH during sexual-stage parasite development. In addition, PyCryPH knockout parasites were generated by targeted gene disruption to examine PyCryPH function in mosquito-stage parasite development. Results Western blot and immunofluorescence assays using specific antibodies showed that PyCryPH is specifically expressed in zygotes and ookinetes. By immunoelectron microscopy it was demonstrated that PyCryPH is localized within crystalloid bodies. Parasites with a disrupted PyCryPH gene developed normally into ookinetes and formed oocysts on the basal lamina of midguts. In addition, the number of sporozoites residing in salivary glands was comparable to that of wild-type parasites. Conclusions CryPH, containing a signal peptide and PH domain, is predominantly expressed in zygotes and ookinetes and is localized to crystalloid bodies in P. yoelii. CryPH accumulates in vesicle-like structures prior to the appearance of typical crystalloid bodies. Unlike other known crystalloid body localized proteins, CryPH does not appear to have a multiple domain architecture characteristic of the LAP/CCp family proteins. Although CryPH is highly conserved among Plasmodium, Babesia, Theileria, and Cryptosporidium, PyCryPH is dispensable for the development of invasive ookinetes and sporozoites in mosquito bodies. Electronic supplementary material The online version of this article (10.1186/s12936-018-2617-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Rachaneeporn Jenwithisuk
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Ehime, 791-0295, Japan.,Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Niwat Kangwanrangsan
- Department of Pathobiology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Mayumi Tachibana
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Ehime, 791-0295, Japan
| | - Amporn Thongkukiatkul
- Department of Biology, Faculty of Science, Burapha University, Chonburi, 20131, Thailand
| | - Hitoshi Otsuki
- Division of Medical Zoology, Faculty of Medicine, Tottori University, Yonago, Tottori, 683-8503, Japan
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, 790-8577, Japan
| | - Motomi Torii
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Ehime, 791-0295, Japan
| | - Tomoko Ishino
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Ehime, 791-0295, Japan.
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54
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Structural and mechanistic insights into the function of the unconventional class XIV myosin MyoA from Toxoplasma gondii. Proc Natl Acad Sci U S A 2018; 115:E10548-E10555. [PMID: 30348763 DOI: 10.1073/pnas.1811167115] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Parasites of the phylum Apicomplexa are responsible for significant morbidity and mortality on a global scale. Central to the virulence of these pathogens are the phylum-specific, unconventional class XIV myosins that power the essential processes of parasite motility and host cell invasion. Notably, class XIV myosins differ from human myosins in key functional regions, yet they are capable of fast movement along actin filaments with kinetics rivaling previously studied myosins. Toward establishing a detailed molecular mechanism of class XIV motility, we determined the 2.6-Å resolution crystal structure of the Toxoplasma gondii MyoA (TgMyoA) motor domain. Structural analysis reveals intriguing strategies for force transduction and chemomechanical coupling that rely on a divergent SH1/SH2 region, the class-defining "HYAG"-site polymorphism, and the actin-binding surface. In vitro motility assays and hydrogen-deuterium exchange coupled with MS further reveal the mechanistic underpinnings of phosphorylation-dependent modulation of TgMyoA motility whereby localized regions of increased stability and order correlate with enhanced motility. Analysis of solvent-accessible pockets reveals striking differences between apicomplexan class XIV and human myosins. Extending these analyses to high-confidence homology models of Plasmodium and Cryptosporidium MyoA motor domains supports the intriguing potential of designing class-specific, yet broadly active, apicomplexan myosin inhibitors. The successful expression of the functional TgMyoA complex combined with our crystal structure of the motor domain provides a strong foundation in support of detailed structure-function studies and enables the development of small-molecule inhibitors targeting these devastating global pathogens.
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Pivovarova Y, Liu J, Lesigang J, Koldyka O, Rauschmeier R, Hu K, Dong G. Structure of a Novel Dimeric SET Domain Methyltransferase that Regulates Cell Motility. J Mol Biol 2018; 430:4209-4229. [PMID: 30148980 PMCID: PMC7141177 DOI: 10.1016/j.jmb.2018.08.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 08/17/2018] [Accepted: 08/21/2018] [Indexed: 11/21/2022]
Abstract
Lysine methyltransferases (KMTs) were initially associated with transcriptional control through their methylation of histones and other nuclear proteins, but have since been found to regulate many other cellular activities. The apical complex lysine (K) methyltransferase (AKMT) of the human parasite Toxoplasma gondii was recently shown to play a critical role in regulating cellular motility. Here we report a 2.1-Å resolution crystal structure of the conserved and functional C-terminal portion (aa289-709) of T. gondii AKMT. AKMT dimerizes via a unique intermolecular interface mediated by the C-terminal tetratricopeptide repeat-like domain together with a specific zinc-binding motif that is absent from all other KMTs. Disruption of AKMT dimerization impaired both its enzyme activity and parasite egress from infected host cells in vivo. Structural comparisons reveal that AKMT is related to the KMTs in the SMYD family, with, however, a number of distinct structural features in addition to the unusual dimerization interface. These features are conserved among the apicomplexan parasites and their free-living relatives, but not found in any known KMTs in animals. AKMT therefore is the founding member of a new subclass of KMT that has important implications for the evolution of the apicomplexans.
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Affiliation(s)
- Yulia Pivovarova
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Jun Liu
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Johannes Lesigang
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | | | - Rene Rauschmeier
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Ke Hu
- Department of Biology, Indiana University, Bloomington, IN 47405, USA.
| | - Gang Dong
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
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56
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Epistasis studies reveal redundancy among calcium-dependent protein kinases in motility and invasion of malaria parasites. Nat Commun 2018; 9:4248. [PMID: 30315162 PMCID: PMC6185908 DOI: 10.1038/s41467-018-06733-w] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 09/24/2018] [Indexed: 12/20/2022] Open
Abstract
In malaria parasites, evolution of parasitism has been linked to functional optimisation. Despite this optimisation, most members of a calcium-dependent protein kinase (CDPK) family show genetic redundancy during erythrocytic proliferation. To identify relationships between phospho-signalling pathways, we here screen 294 genetic interactions among protein kinases in Plasmodium berghei. This reveals a synthetic negative interaction between a hypomorphic allele of the protein kinase G (PKG) and CDPK4 to control erythrocyte invasion which is conserved in P. falciparum. CDPK4 becomes critical when PKG-dependent calcium signals are attenuated to phosphorylate proteins important for the stability of the inner membrane complex, which serves as an anchor for the acto-myosin motor required for motility and invasion. Finally, we show that multiple kinases functionally complement CDPK4 during erythrocytic proliferation and transmission to the mosquito. This study reveals how CDPKs are wired within a stage-transcending signalling network to control motility and host cell invasion in malaria parasites. Despite functional optimisation during evolution of parasitism, most members of a calcium dependent protein kinase (CDPK) family show genetic redundancy in Plasmodium. Here, the authors screen 294 genetic interactions among protein kinases in Plasmodium and show how some CDPKs functionally interact to control motility and host cell invasion.
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57
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Uboldi AD, Wilde ML, McRae EA, Stewart RJ, Dagley LF, Yang L, Katris NJ, Hapuarachchi SV, Coffey MJ, Lehane AM, Botte CY, Waller RF, Webb AI, McConville MJ, Tonkin CJ. Protein kinase A negatively regulates Ca2+ signalling in Toxoplasma gondii. PLoS Biol 2018; 16:e2005642. [PMID: 30208022 PMCID: PMC6152992 DOI: 10.1371/journal.pbio.2005642] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 09/24/2018] [Accepted: 08/20/2018] [Indexed: 11/18/2022] Open
Abstract
The phylum Apicomplexa comprises a group of obligate intracellular parasites that alternate between intracellular replicating stages and actively motile extracellular forms that move through tissue. Parasite cytosolic Ca2+ signalling activates motility, but how this is switched off after invasion is complete to allow for replication to begin is not understood. Here, we show that the cyclic adenosine monophosphate (cAMP)-dependent protein kinase A catalytic subunit 1 (PKAc1) of Toxoplasma is responsible for suppression of Ca2+ signalling upon host cell invasion. We demonstrate that PKAc1 is sequestered to the parasite periphery by dual acylation of PKA regulatory subunit 1 (PKAr1). Upon genetic depletion of PKAc1 we show that newly invaded parasites exit host cells shortly thereafter, in a perforin-like protein 1 (PLP-1)-dependent fashion. Furthermore, we demonstrate that loss of PKAc1 prevents rapid down-regulation of cytosolic [Ca2+] levels shortly after invasion. We also provide evidence that loss of PKAc1 sensitises parasites to cyclic GMP (cGMP)-induced Ca2+ signalling, thus demonstrating a functional link between cAMP and these other signalling modalities. Together, this work provides a new paradigm in understanding how Toxoplasma and related apicomplexan parasites regulate infectivity. Central to pathogenesis and infectivity of Toxoplasma and related parasites is their ability to move through tissue, invade host cells, and establish a replicative niche. Ca2+-dependent signalling pathways are important for activating motility, host cell invasion, and egress, yet how this signalling is turned off after invasion is unclear. Here, we show that a cAMP-dependent protein kinase A (PKA) is essential for rapid suppression of Ca2+ signalling upon completion of host cell invasion. Parasites lacking this kinase rapidly invoke an egress program to re-exit host cells, thus preventing the establishment of a stable infection. This finding therefore highlights the first factor required for Toxoplasma (and any related apicomplexan parasite) to switch from invasive to the replicative forms.
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Affiliation(s)
- Alessandro D. Uboldi
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Mary-Louise Wilde
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Emi A. McRae
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Rebecca J. Stewart
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Laura F. Dagley
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Luning Yang
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
- School of Medicine, Tsinghua University, Beijing, China
| | - Nicholas J. Katris
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
- Institute of Advanced Biosciences, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, Grenoble, France
| | | | - Michael J. Coffey
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Adele M. Lehane
- Research School of Biology, The Australian National University, A.C.T., Australia
| | - Cyrille Y. Botte
- Institute of Advanced Biosciences, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, Grenoble, France
| | - Ross F. Waller
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Andrew I. Webb
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Malcolm J. McConville
- Department of Biochemistry and Molecular Biology, Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Australia
| | - Christopher J. Tonkin
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
- * E-mail:
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58
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Douglas RG, Reinig M, Neale M, Frischknecht F. Screening for potential prophylactics targeting sporozoite motility through the skin. Malar J 2018; 17:319. [PMID: 30170589 PMCID: PMC6119338 DOI: 10.1186/s12936-018-2469-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 08/27/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Anti-malarial compounds have not yet been identified that target the first obligatory step of infection in humans: the migration of Plasmodium sporozoites in the host dermis. This movement is essential to find and invade a blood vessel in order to be passively transported to the liver. Here, an imaging screening pipeline was established to screen for compounds capable of inhibiting extracellular sporozoites. METHODS Sporozoites expressing the green fluorescent protein were isolated from infected Anopheles mosquitoes, incubated with compounds from two libraries (MMV Malaria Box and a FDA-approved library) and imaged. Effects on in vitro motility or morphology were scored. In vivo efficacy of a candidate drug was investigated by treating mice ears with a gel prior to infectious mosquito bites. Motility was analysed by in vivo imaging and the progress of infection was monitored by daily blood smears. RESULTS Several compounds had a pronounced effect on in vitro sporozoite gliding or morphology. Notably, monensin sodium potently affected sporozoite movement while gramicidin S resulted in rounding up of sporozoites. However, pre-treatment of mice with a topical gel containing gramicidin did not reduce sporozoite motility and infection. CONCLUSIONS This approach shows that it is possible to screen libraries for inhibitors of sporozoite motility and highlighted the paucity of compounds in currently available libraries that inhibit this initial step of a malaria infection. Screening of diverse libraries is suggested to identify more compounds that could serve as leads in developing 'skin-based' malaria prophylactics. Further, strategies need to be developed that will allow compounds to effectively penetrate the dermis and thereby prevent exit of sporozoites from the skin.
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Affiliation(s)
- Ross G Douglas
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany.
| | - Miriam Reinig
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
| | - Matthew Neale
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
| | - Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany.
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Darvill N, Dubois DJ, Rouse SL, Hammoudi PM, Blake T, Benjamin S, Liu B, Soldati-Favre D, Matthews S. Structural Basis of Phosphatidic Acid Sensing by APH in Apicomplexan Parasites. Structure 2018; 26:1059-1071.e6. [PMID: 29910186 PMCID: PMC6084407 DOI: 10.1016/j.str.2018.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 03/26/2018] [Accepted: 05/08/2018] [Indexed: 10/29/2022]
Abstract
Plasmodium falciparum and Toxoplasma gondii are obligate intracellular parasites that belong to the phylum of Apicomplexa and cause major human diseases. Their access to an intracellular lifestyle is reliant on the coordinated release of proteins from the specialized apical organelles called micronemes and rhoptries. A specific phosphatidic acid effector, the acylated pleckstrin homology domain-containing protein (APH) plays a central role in microneme exocytosis and thus is essential for motility, cell entry, and egress. TgAPH is acylated on the surface of the micronemes and recruited to phosphatidic acid (PA)-enriched membranes. Here, we dissect the atomic details of APH PA-sensing hub and its functional interaction with phospholipid membranes. We unravel the key determinant of PA recognition for the first time and show that APH inserts into and clusters multiple phosphate head-groups at the bilayer binding surface.
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Affiliation(s)
- Nick Darvill
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - David J Dubois
- Department of Microbiology & Molecular Medicine, Faculty of Medicine, University of Geneva, 1 Rue Michel-Servet, 1211 Geneva, Switzerland
| | - Sarah L Rouse
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Pierre-Mehdi Hammoudi
- Department of Microbiology & Molecular Medicine, Faculty of Medicine, University of Geneva, 1 Rue Michel-Servet, 1211 Geneva, Switzerland
| | - Tom Blake
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Stefi Benjamin
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Bing Liu
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK; BioBank, First Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Dominique Soldati-Favre
- Department of Microbiology & Molecular Medicine, Faculty of Medicine, University of Geneva, 1 Rue Michel-Servet, 1211 Geneva, Switzerland.
| | - Steve Matthews
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK; BioBank, First Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
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Boucher LE, Hopp CS, Muthinja JM, Frischknecht F, Bosch J. Discovery of Plasmodium (M)TRAP-Aldolase Interaction Stabilizers Interfering with Sporozoite Motility and Invasion. ACS Infect Dis 2018; 4:620-634. [PMID: 29411968 DOI: 10.1021/acsinfecdis.7b00225] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
As obligate, intracellular parasites, Plasmodium spp. rely on invasion of host cells in order to replicate and continue their life cycle. The parasite needs to traverse the dermis and endothelium of blood vessels, invade hepatocytes and red blood cells, traverse the mosquito midgut, and enter the salivary glands to continue the cycle of infection and transmission. To traverse and invade cells, the parasite employs an actomyosin motor at the core of a larger invasion machinery complex known as the glideosome. The complex is comprised of multiple protein-protein interactions linking the motor to the internal cytoskeletal network of the parasite and to the extracellular adhesins, which directly contact the host tissue or cell surface. One key interaction is between the cytoplasmic tails of the thrombospondin related anonymous protein (TRAP) and aldolase, a bridging protein to the motor. Here, we present results from screening the Medicines for Malaria Venture (MMV) library of 400 compounds against this key protein-protein interaction. Using a surface plasmon resonance screen, we have identified several compounds that modulate the dynamics of the interaction between TRAP and aldolase. These compounds have been validated in vitro by studying their effects on sporozoite gliding motility and hepatocyte invasion. One of the MMV compounds identified reduced invasion levels by 89% at the lowest concentration tested (16 μM) and severely inhibited gliding at even lower concentrations (5 μM). By targeting protein-protein interactions, we investigated an under-explored area of parasite biology and general drug development, to identify potential antimalarial lead compounds.
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Affiliation(s)
- Lauren E. Boucher
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, Maryland 21205, United States
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, Maryland 21205, United States
| | - Christine S. Hopp
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, Maryland 21205, United States
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, Maryland 21205, United States
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 5625 Fishers Lane, Rockville, Maryland 20852, United States
| | - Julianne Mendi Muthinja
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Jürgen Bosch
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, Maryland 21205, United States
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, Maryland 21205, United States
- InterRayBio, LLC, 1812 Ashland Avenue, Baltimore, Maryland 21205, United States
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Abstract
Plasmodium species cause malaria by proliferating in human erythrocytes. Invasion of immunologically privileged erythrocytes provides a relatively protective niche as well as access to a rich source of nutrients. Plasmodium spp. target erythrocytes of different ages, but share a common mechanism of invasion. Specific engagement of erythrocyte receptors defines target cell tropism, activating downstream events and resulting in the physical penetration of the erythrocyte, powered by the parasite's actinomyosin-based motor. Here we review the latest in our understanding of the molecular composition of this highly complex and fascinating biological process.
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Kumar K, Srinivasan P, Nold MJ, Moch JK, Reiter K, Sturdevant D, Otto TD, Squires RB, Herrera R, Nagarajan V, Rayner JC, Porcella SF, Geromanos SJ, Haynes JD, Narum DL. Profiling invasive Plasmodium falciparum merozoites using an integrated omics approach. Sci Rep 2017; 7:17146. [PMID: 29215067 PMCID: PMC5719419 DOI: 10.1038/s41598-017-17505-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 11/22/2017] [Indexed: 02/06/2023] Open
Abstract
The symptoms of malaria are brought about by blood-stage parasites, which are established when merozoites invade human erythrocytes. Our understanding of the molecular events that underpin erythrocyte invasion remains hampered by the short-period of time that merozoites are invasive. To address this challenge, a Plasmodium falciparum gamma-irradiated long-lived merozoite (LLM) line was developed and investigated. Purified LLMs invaded erythrocytes by an increase of 10–300 fold compared to wild-type (WT) merozoites. Using an integrated omics approach, we investigated the basis for the phenotypic difference. Only a few single nucleotide polymorphisms within the P. falciparum genome were identified and only marginal differences were observed in the merozoite transcriptomes. By contrast, using label-free quantitative mass-spectrometry, a significant change in protein abundance was noted, of which 200 were proteins of unknown function. We determined the relative molar abundance of over 1100 proteins in LLMs and further characterized the major merozoite surface protein complex. A unique processed MSP1 intermediate was identified in LLM but not observed in WT suggesting that delayed processing may be important for the observed phenotype. This integrated approach has demonstrated the significant role of the merozoite proteome during erythrocyte invasion, while identifying numerous unknown proteins likely to be involved in invasion.
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Affiliation(s)
- Krishan Kumar
- Laboratory of Malaria Immunology and Vaccinology, NIAID, NIH, Rockville, MD, USA
| | - Prakash Srinivasan
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, USA. .,Johns Hopkins Malaria Research Institute, Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | | | - J Kathleen Moch
- Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Karine Reiter
- Laboratory of Malaria Immunology and Vaccinology, NIAID, NIH, Rockville, MD, USA
| | - Dan Sturdevant
- Genomics Unit, Research Technologies Section, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, MT, USA
| | - Thomas D Otto
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, United Kingdom
| | - R Burke Squires
- Computational Biology Section, Bioinformatics and Computational Biosciences Branch, NIAID, NIH, Bethesda, MD, USA
| | - Raul Herrera
- Laboratory of Malaria Immunology and Vaccinology, NIAID, NIH, Rockville, MD, USA
| | - Vijayaraj Nagarajan
- Computational Biology Section, Bioinformatics and Computational Biosciences Branch, NIAID, NIH, Bethesda, MD, USA
| | - Julian C Rayner
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, United Kingdom
| | - Stephen F Porcella
- Genomics Unit, Research Technologies Section, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, MT, USA
| | | | - J David Haynes
- Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - David L Narum
- Laboratory of Malaria Immunology and Vaccinology, NIAID, NIH, Rockville, MD, USA.
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63
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Two Phosphoglucomutase Paralogs Facilitate Ionophore-Triggered Secretion of the Toxoplasma Micronemes. mSphere 2017; 2:mSphere00521-17. [PMID: 29202046 PMCID: PMC5705807 DOI: 10.1128/msphere.00521-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 11/05/2017] [Indexed: 12/28/2022] Open
Abstract
Ca2+-dependent exocytosis is essential for the life cycle of apicomplexan parasites. Toxoplasma gondii harbors a phosphoglucomutase (PGM) ortholog, PRP1, previously associated with Ca2+-dependent microneme secretion. Here it is shown that genetic deletion of either PRP1, its PGM2 ortholog, or both genes is dispensable for the parasite’s lytic cycle, including host cell egress and invasion. Depletion of the proteins abrogated high Ca2+-mediated microneme secretion induced by the ionophore A23187; however, the constitutive and phosphatidic acid-mediated release remained unaffected. Secretion mediated by the former pathway is not essential for tachyzoite survival or acute in vivo infection in the mice. Paralogs of the widely prevalent phosphoglucomutase (PGM) protein called parafusin function in calcium (Ca2+)-mediated exocytosis across eukaryotes. In Toxoplasma gondii, the parafusin-related protein 1 (PRP1) has been associated with Ca2+-dependent microneme organelle secretion required for essential processes like host cell invasion and egress. Using reverse genetics, we observed PRP1 to be dispensable for completion of the lytic cycle, including host cell invasion and egress by the parasite. However, the absence of the gene affected increased microneme release triggered by A23187, a Ca2+ ionophore used to raise the cytoplasmic Ca2+ concentration mimicking the physiological role of Ca2+ during invasion and egress. The basal levels of constitutive microneme release in extracellular parasites and phosphatidic acid-triggered microneme secretion were unaffected in the mutant. The phenotype of the deletion mutant of the second PGM-encoding gene in Toxoplasma, PGM2, was similar to the phenotype of the PRP1 deletion mutant. Furthermore, the ability of the tachyzoites to induce acute infection in the mice remained normal in the absence of both PGM paralogs. Our data thus reveal that the microneme secretion upon high Ca2+ flux is facilitated by the Toxoplasma PGM paralogs, PRP1 and PGM2. However, this protein-mediated release is neither essential for lytic cycle completion nor for acute virulence of the parasite. IMPORTANCE Ca2+-dependent exocytosis is essential for the life cycle of apicomplexan parasites. Toxoplasma gondii harbors a phosphoglucomutase (PGM) ortholog, PRP1, previously associated with Ca2+-dependent microneme secretion. Here it is shown that genetic deletion of either PRP1, its PGM2 ortholog, or both genes is dispensable for the parasite’s lytic cycle, including host cell egress and invasion. Depletion of the proteins abrogated high Ca2+-mediated microneme secretion induced by the ionophore A23187; however, the constitutive and phosphatidic acid-mediated release remained unaffected. Secretion mediated by the former pathway is not essential for tachyzoite survival or acute in vivo infection in the mice.
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64
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Saini E, Zeeshan M, Brady D, Pandey R, Kaiser G, Koreny L, Kumar P, Thakur V, Tatiya S, Katris NJ, Limenitakis RS, Kaur I, Green JL, Bottrill AR, Guttery DS, Waller RF, Heussler V, Holder AA, Mohmmed A, Malhotra P, Tewari R. Photosensitized INA-Labelled protein 1 (PhIL1) is novel component of the inner membrane complex and is required for Plasmodium parasite development. Sci Rep 2017; 7:15577. [PMID: 29138437 PMCID: PMC5686188 DOI: 10.1038/s41598-017-15781-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 11/01/2017] [Indexed: 11/09/2022] Open
Abstract
Plasmodium parasites, the causative agents of malaria, possess a distinctive membranous structure of flattened alveolar vesicles supported by a proteinaceous network, and referred to as the inner membrane complex (IMC). The IMC has a role in actomyosin-mediated motility and host cell invasion. Here, we examine the location, protein interactome and function of PhIL1, an IMC-associated protein on the motile and invasive stages of both human and rodent parasites. We show that PhIL1 is located in the IMC in all three invasive (merozoite, ookinete-, and sporozoite) stages of development, as well as in the male gametocyte and locates both at the apical and basal ends of ookinete and sporozoite stages. Proteins interacting with PhIL1 were identified, showing that PhIL1 was bound to only some proteins present in the glideosome motor complex (GAP50, GAPM1–3) of both P. falciparum and P. berghei. Analysis of PhIL1 function using gene targeting approaches indicated that the protein is required for both asexual and sexual stages of development. In conclusion, we show that PhIL1 is required for development of all zoite stages of Plasmodium and it is part of a novel protein complex with an overall composition overlapping with but different to that of the glideosome.
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Affiliation(s)
- Ekta Saini
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Mohammad Zeeshan
- School of Life Sciences, University of Nottingham, Nottingham, NG72UH, UK
| | - Declan Brady
- School of Life Sciences, University of Nottingham, Nottingham, NG72UH, UK
| | - Rajan Pandey
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Gesine Kaiser
- Institute of Cell Biology, University of Bern, Bern, 3012, Switzerland
| | - Ludek Koreny
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Pradeep Kumar
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Vandana Thakur
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Shreyansh Tatiya
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Nicholas J Katris
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | | | - Inderjeet Kaur
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | | | - Andrew R Bottrill
- Protein and Nucleic Acid Chemistry Laboratory, University of Leicester, Leicester, LE2 7LX, UK
| | - David S Guttery
- Department of Cancer studies, University of Leicester, Leicester, LE2 7LX, UK
| | - Ross F Waller
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Volker Heussler
- Institute of Cell Biology, University of Bern, Bern, 3012, Switzerland
| | | | - Asif Mohmmed
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Pawan Malhotra
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India.
| | - Rita Tewari
- School of Life Sciences, University of Nottingham, Nottingham, NG72UH, UK.
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65
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Songsungthong W, Kulawonganunchai S, Wilantho A, Tongsima S, Koonyosying P, Uthaipibull C, Kamchonwongpaisan S, Shaw PJ. The Plasmodium berghei RC strain is highly diverged and harbors putatively novel drug resistance variants. PeerJ 2017; 5:e3766. [PMID: 29018598 PMCID: PMC5632537 DOI: 10.7717/peerj.3766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 08/15/2017] [Indexed: 11/20/2022] Open
Abstract
Background The current first line drugs for treating uncomplicated malaria are artemisinin (ART) combination therapies. However, Plasmodium falciparum parasites resistant to ART and partner drugs are spreading, which threatens malaria control efforts. Rodent malaria species are useful models for understanding antimalarial resistance, in particular genetic variants responsible for cross resistance to different compounds. Methods The Plasmodium berghei RC strain (PbRC) is described as resistant to different antimalarials, including chloroquine (CQ) and ART. In an attempt to identify the genetic basis for the antimalarial resistance trait in PbRC, its genome was sequenced and compared with five other previously sequenced P. berghei strains. Results We found that PbRC is eight-fold less sensitive to the ART derivative artesunate than the reference strain PbANKA. The genome of PbRC is markedly different from other strains, and 6,974 single nucleotide variants private to PbRC were identified. Among these PbRC private variants, non-synonymous changes were identified in genes known to modulate antimalarial sensitivity in rodent malaria species, including notably the ubiquitin carboxyl-terminal hydrolase 1 gene. However, no variants were found in some genes with strong evidence of association with ART resistance in P. falciparum such as K13 propeller protein. Discussion The variants identified in PbRC provide insight into P. berghei genome diversity and genetic factors that could modulate CQ and ART resistance in Plasmodium spp.
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Affiliation(s)
- Warangkhana Songsungthong
- Protein-Ligand Engineering and Molecular Biology Laboratory, Medical Molecular Biology Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand.,Biomolecular Analysis and Application Laboratory, Biosensing Technology Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand
| | - Supasak Kulawonganunchai
- Biostatistics and Bioinformatics Laboratory, Genome Technology Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand
| | - Alisa Wilantho
- Biostatistics and Bioinformatics Laboratory, Genome Technology Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand
| | - Sissades Tongsima
- Biostatistics and Bioinformatics Laboratory, Genome Technology Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand
| | - Pongpisid Koonyosying
- Protein-Ligand Engineering and Molecular Biology Laboratory, Medical Molecular Biology Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand
| | - Chairat Uthaipibull
- Protein-Ligand Engineering and Molecular Biology Laboratory, Medical Molecular Biology Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand
| | - Sumalee Kamchonwongpaisan
- Protein-Ligand Engineering and Molecular Biology Laboratory, Medical Molecular Biology Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand
| | - Philip J Shaw
- Protein-Ligand Engineering and Molecular Biology Laboratory, Medical Molecular Biology Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand
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66
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Kumpula EP, Pires I, Lasiwa D, Piirainen H, Bergmann U, Vahokoski J, Kursula I. Apicomplexan actin polymerization depends on nucleation. Sci Rep 2017; 7:12137. [PMID: 28939886 PMCID: PMC5610305 DOI: 10.1038/s41598-017-11330-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/22/2017] [Indexed: 01/21/2023] Open
Abstract
Filamentous actin is critical for apicomplexan motility and host cell invasion. Yet, parasite actin filaments are short and unstable. Their kinetic characterization has been hampered by the lack of robust quantitative methods. Using a modified labeling method, we carried out thorough biochemical characterization of malaria parasite actin. In contrast to the isodesmic polymerization mechanism suggested for Toxoplasma gondii actin, Plasmodium falciparum actin I polymerizes via the classical nucleation-elongation pathway, with kinetics similar to canonical actins. A high fragmentation rate, governed by weak lateral contacts within the filament, is likely the main reason for the short filament length. At steady state, Plasmodium actin is present in equal amounts of short filaments and dimers, with a small proportion of monomers, representing the apparent critical concentration of ~0.1 µM. The dimers polymerize but do not serve as nuclei. Our work enhances understanding of actin evolution and the mechanistic details of parasite motility, serving as a basis for exploring parasite actin and actin nucleators as drug targets against malaria and other apicomplexan parasitic diseases.
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Affiliation(s)
- Esa-Pekka Kumpula
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7, 90220, Oulu, Finland
| | - Isa Pires
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7, 90220, Oulu, Finland
| | - Devaki Lasiwa
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7, 90220, Oulu, Finland
| | - Henni Piirainen
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7, 90220, Oulu, Finland
| | - Ulrich Bergmann
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7, 90220, Oulu, Finland
| | - Juha Vahokoski
- 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
| | - 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.
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67
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Near-atomic structure of jasplakinolide-stabilized malaria parasite F-actin reveals the structural basis of filament instability. Proc Natl Acad Sci U S A 2017; 114:10636-10641. [PMID: 28923924 DOI: 10.1073/pnas.1707506114] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
During their life cycle, apicomplexan parasites, such as the malaria parasite Plasmodium falciparum, use actomyosin-driven gliding motility to move and invade host cells. For this process, actin filament length and stability are temporally and spatially controlled. In contrast to canonical actin, P. falciparum actin 1 (PfAct1) does not readily polymerize into long, stable filaments. The structural basis of filament instability, which plays a pivotal role in host cell invasion, and thus infectivity, is poorly understood, largely because high-resolution structures of PfAct1 filaments were missing. Here, we report the near-atomic structure of jasplakinolide (JAS)-stabilized PfAct1 filaments determined by electron cryomicroscopy. The general filament architecture is similar to that of mammalian F-actin. The high resolution of the structure allowed us to identify small but important differences at inter- and intrastrand contact sites, explaining the inherent instability of apicomplexan actin filaments. JAS binds at regular intervals inside the filament to three adjacent actin subunits, reinforcing filament stability by hydrophobic interactions. Our study reveals the high-resolution structure of a small molecule bound to F-actin, highlighting the potential of electron cryomicroscopy for structure-based drug design. Furthermore, our work serves as a strong foundation for understanding the structural design and evolution of actin filaments and their function in motility and host cell invasion of apicomplexan parasites.
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68
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Dogga SK, Mukherjee B, Jacot D, Kockmann T, Molino L, Hammoudi PM, Hartkoorn RC, Hehl AB, Soldati-Favre D. A druggable secretory protein maturase of Toxoplasma essential for invasion and egress. eLife 2017; 6. [PMID: 28898199 PMCID: PMC5595437 DOI: 10.7554/elife.27480] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 08/08/2017] [Indexed: 12/19/2022] Open
Abstract
Micronemes and rhoptries are specialized secretory organelles that deploy their contents at the apical tip of apicomplexan parasites in a regulated manner. The secretory proteins participate in motility, invasion, and egress and are subjected to proteolytic maturation prior to organellar storage and discharge. Here we establish that Toxoplasma gondii aspartyl protease 3 (ASP3) resides in the endosomal-like compartment and is crucially associated to rhoptry discharge during invasion and to host cell plasma membrane lysis during egress. A comparison of the N-terminome, by terminal amine isotopic labelling of substrates between wild type and ASP3 depleted parasites identified microneme and rhoptry proteins as repertoire of ASP3 substrates. The role of ASP3 as a maturase for previously described and newly identified secretory proteins is confirmed in vivo and in vitro. An antimalarial compound based on a hydroxyethylamine scaffold interrupts the lytic cycle of T. gondii at submicromolar concentration by targeting ASP3.
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Affiliation(s)
- Sunil Kumar Dogga
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Budhaditya Mukherjee
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Damien Jacot
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Tobias Kockmann
- Functional Genomics Center Zurich, ETH Zurich/University of Zurich, Zurich, Switzerland
| | - Luca Molino
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Pierre-Mehdi Hammoudi
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Ruben C Hartkoorn
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland.,Chemical Biology of Antibiotics, Center for Infection and Immunity, Inserm U1019, CNRS UMR8204, Institut Pasteur de Lille, Lille, France
| | - Adrian B Hehl
- Institute of Parasitology, University of Zurich, Zurich, Switzerland
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
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69
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70
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Proteogenomic analysis of the total and surface-exposed proteomes of Plasmodium vivax salivary gland sporozoites. PLoS Negl Trop Dis 2017; 11:e0005791. [PMID: 28759593 PMCID: PMC5552340 DOI: 10.1371/journal.pntd.0005791] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 08/10/2017] [Accepted: 07/10/2017] [Indexed: 12/29/2022] Open
Abstract
Plasmodium falciparum and Plasmodium vivax cause the majority of human malaria cases. Research efforts predominantly focus on P. falciparum because of the clinical severity of infection and associated mortality rates. However, P. vivax malaria affects more people in a wider global range. Furthermore, unlike P. falciparum, P. vivax can persist in the liver as dormant hypnozoites that can be activated weeks to years after primary infection, causing relapse of symptomatic blood stages. This feature makes P. vivax unique and difficult to eliminate with the standard tools of vector control and treatment of symptomatic blood stage infection with antimalarial drugs. Infection by Plasmodium is initiated by the mosquito-transmitted sporozoite stage, a highly motile invasive cell that targets hepatocytes in the liver. The most advanced malaria vaccine for P. falciparum (RTS,S, a subunit vaccine containing of a portion of the major sporozoite surface protein) conferred limited protection in Phase III trials, falling short of WHO-established vaccine efficacy goals. However, blocking the sporozoite stage of infection in P. vivax, before the establishment of the chronic liver infection, might be an effective malaria vaccine strategy to reduce the occurrence of relapsing blood stages. It is also thought that a multivalent vaccine comprising multiple sporozoite surface antigens will provide better protection, but a comprehensive analysis of proteins in P. vivax sporozoites is not available. To inform sporozoite-based vaccine development, we employed mass spectrometry-based proteomics to identify nearly 2,000 proteins present in P. vivax salivary gland sporozoites. Analysis of protein post-translational modifications revealed extensive phosphorylation of glideosome proteins as well as regulators of transcription and translation. Additionally, the sporozoite surface proteins CSP and TRAP, which were recently discovered to be glycosylated in P. falciparum salivary gland sporozoites, were also observed to be similarly modified in P. vivax sporozoites. Quantitative comparison of the P. vivax and P. falciparum salivary gland sporozoite proteomes revealed a high degree of similarity in protein expression levels, including among invasion-related proteins. Nevertheless, orthologs with significantly different expression levels between the two species could be identified, as well as highly abundant, species-specific proteins with no known orthologs. Finally, we employed chemical labeling of live sporozoites to isolate and identify 36 proteins that are putatively surface-exposed on P. vivax salivary gland sporozoites. In addition to identifying conserved sporozoite surface proteins identified by similar analyses of other Plasmodium species, our analysis identified several as-yet uncharacterized proteins, including a putative 6-Cys protein with no known ortholog in P. falciparum. Malaria is one of the most important infectious diseases in the world with hundreds of millions of new cases every year. Malaria is caused by parasites of the genus Plasmodium which have a complex life cycle, alternating between mosquito and mammalian hosts. Human infections are initiated with a sporozoite inoculum deposited into the skin by parasite-infected mosquitoes as they probe for blood. Sporozoites must locate blood vessels and enter the circulation to reach the liver where they invade and grow in hepatocytes. In the case of Plasmodium vivax, one of the two Plasmodium species responsible for the majority of the disease burden in the world, the parasite has the ability to persist for months in the liver after the initial infection and its activation causes the recurring appearance of the parasite in the blood. Though all clinical symptoms are attributable to the blood stages, it is only by attacking the transmission stages before the formation of hypnozoites (the persisting parasites in the liver) that an impact on the burden of vivax malaria can be achieved. We used state-of-the-art mass spectrometry-based proteomics tools to identify the total protein make-up of P. vivax sporozoites. By analyzing which proteins are exposed to the parasite surface and determining the degree of protein’s post-translational modifications, our investigation will aid the understanding of the novel biology of sporozoites and importantly, advise the development of potential vaccine candidates targeting this parasite stage.
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Gras S, Jackson A, Woods S, Pall G, Whitelaw J, Leung JM, Ward GE, Roberts CW, Meissner M. Parasites lacking the micronemal protein MIC2 are deficient in surface attachment and host cell egress, but remain virulent in vivo. Wellcome Open Res 2017. [PMID: 28630943 PMCID: PMC5473411 DOI: 10.12688/wellcomeopenres.11594.2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: Micronemal proteins of the thrombospondin-related anonymous protein (TRAP) family are believed to play essential roles during gliding motility and host cell invasion by apicomplexan parasites, and currently represent major vaccine candidates against
Plasmodium falciparum, the causative agent of malaria. However, recent evidence suggests that they play multiple and different roles than previously assumed. Here, we analyse a null mutant for MIC2, the TRAP homolog in
Toxoplasma gondii.
Methods: We performed a careful analysis of parasite motility in a 3D-environment, attachment under shear stress conditions, host cell invasion and
in vivo virulence.
Results: We verified the role of MIC2 in efficient surface attachment, but were unable to identify any direct function of MIC2 in sustaining gliding motility or host cell invasion once initiated. Furthermore, we find that deletion of
mic2 causes a slightly delayed infection
in vivo, leading only to mild attenuation of virulence; like with wildtype parasites, inoculation with even low numbers of
mic2 KO parasites causes lethal disease in mice. However, deletion of
mic2 causes delayed host cell egress
in vitro, possibly via disrupted signal transduction pathways.
Conclusions: We confirm a critical role of MIC2 in parasite attachment to the surface, leading to reduced parasite motility and host cell invasion. However, MIC2 appears to not be critical for gliding motility or host cell invasion, since parasite speed during these processes is unaffected. Furthermore, deletion of MIC2 leads only to slight attenuation of the parasite.
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Affiliation(s)
- Simon Gras
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, G12 8TA, UK
| | - Allison Jackson
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, G12 8TA, UK
| | - Stuart Woods
- Strathclyde Institute of Pharmacy and Biomedical Sciences, Glasgow, G4 0RE, UK
| | - Gurman Pall
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, G12 8TA, UK
| | - Jamie Whitelaw
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, G12 8TA, UK
| | - Jacqueline M Leung
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA.,Department of Microbiology and Molecular Genetics, College of Medicine, University of Vermont, Burlington, VT, 05405, USA
| | - Gary E Ward
- Department of Microbiology and Molecular Genetics, College of Medicine, University of Vermont, Burlington, VT, 05405, USA
| | - Craig W Roberts
- Strathclyde Institute of Pharmacy and Biomedical Sciences, Glasgow, G4 0RE, UK
| | - Markus Meissner
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, G12 8TA, UK
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Gras S, Jackson A, Woods S, Pall G, Whitelaw J, Leung JM, Ward GE, Roberts CW, Meissner M. Parasites lacking the micronemal protein MIC2 are deficient in surface attachment and host cell egress, but remain virulent in vivo. Wellcome Open Res 2017. [PMID: 28630943 DOI: 10.12688/wellcomeopenres.11594.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: Micronemal proteins of the thrombospondin-related anonymous protein (TRAP) family are believed to play essential roles during gliding motility and host cell invasion by apicomplexan parasites, and currently represent major vaccine candidates against Plasmodium falciparum, the causative agent of malaria. However, recent evidence suggests that they play multiple and different roles than previously assumed. Here, we analyse a null mutant for MIC2, the TRAP homolog in Toxoplasma gondii. Methods: We performed a careful analysis of parasite motility in a 3D-environment, attachment under shear stress conditions, host cell invasion and in vivo virulence. Results: We verified the role of MIC2 in efficient surface attachment, but were unable to identify any direct function of MIC2 in sustaining gliding motility or host cell invasion once initiated. Furthermore, we find that deletion of mic2 causes a slightly delayed infection in vivo, leading only to mild attenuation of virulence; like with wildtype parasites, inoculation with even low numbers of mic2 KO parasites causes lethal disease in mice. However, deletion of mic2 causes delayed host cell egress in vitro, possibly via disrupted signal transduction pathways. Conclusions: We confirm a critical role of MIC2 in parasite attachment to the surface, leading to reduced parasite motility and host cell invasion. However, MIC2 appears to not be critical for gliding motility or host cell invasion, since parasite speed during these processes is unaffected. Furthermore, deletion of MIC2 leads only to slight attenuation of the parasite.
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Affiliation(s)
- Simon Gras
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, G12 8TA, UK
| | - Allison Jackson
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, G12 8TA, UK
| | - Stuart Woods
- Strathclyde Institute of Pharmacy and Biomedical Sciences, Glasgow, G4 0RE, UK
| | - Gurman Pall
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, G12 8TA, UK
| | - Jamie Whitelaw
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, G12 8TA, UK
| | - Jacqueline M Leung
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA.,Department of Microbiology and Molecular Genetics, College of Medicine, University of Vermont, Burlington, VT, 05405, USA
| | - Gary E Ward
- Department of Microbiology and Molecular Genetics, College of Medicine, University of Vermont, Burlington, VT, 05405, USA
| | - Craig W Roberts
- Strathclyde Institute of Pharmacy and Biomedical Sciences, Glasgow, G4 0RE, UK
| | - Markus Meissner
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, G12 8TA, UK
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73
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Moreau CA, Bhargav SP, Kumar H, Quadt KA, Piirainen H, Strauss L, Kehrer J, Streichfuss M, Spatz JP, Wade RC, Kursula I, Frischknecht F. A unique profilin-actin interface is important for malaria parasite motility. PLoS Pathog 2017; 13:e1006412. [PMID: 28552953 PMCID: PMC5464670 DOI: 10.1371/journal.ppat.1006412] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 06/08/2017] [Accepted: 05/16/2017] [Indexed: 11/30/2022] Open
Abstract
Profilin is an actin monomer binding protein that provides ATP-actin for incorporation into actin filaments. In contrast to higher eukaryotic cells with their large filamentous actin structures, apicomplexan parasites typically contain only short and highly dynamic microfilaments. In apicomplexans, profilin appears to be the main monomer-sequestering protein. Compared to classical profilins, apicomplexan profilins contain an additional arm-like β-hairpin motif, which we show here to be critically involved in actin binding. Through comparative analysis using two profilin mutants, we reveal this motif to be implicated in gliding motility of Plasmodium berghei sporozoites, the rapidly migrating forms of a rodent malaria parasite transmitted by mosquitoes. Force measurements on migrating sporozoites and molecular dynamics simulations indicate that the interaction between actin and profilin fine-tunes gliding motility. Our data suggest that evolutionary pressure to achieve efficient high-speed gliding has resulted in a unique profilin-actin interface in these parasites. The malaria parasite Plasmodium has two invasive forms that migrate across different tissue barriers, the ookinete and the very rapidly migrating sporozoite. Previous work has shown that the motility of these and related parasites (e.g. Toxoplasma gondii) depends on a highly dynamic actin cytoskeleton and retrograde flow of surface adhesins. These unusual actin dynamics are due to the divergent structure of protozoan actins and the actions of actin-binding proteins, which can have non-canonical functions in these parasites. Profilin is one of the most important and most investigated actin-binding proteins, which binds ADP-actin and catalyzes ADP-ATP exchange to then promote actin polymerization. Parasite profilins bind monomeric actin and contain an additional domain compared to canonical profilins. Here we show that this additional domain of profilin is critical for actin binding and rapid sporozoite motility but has little impact on the slower ookinete. Sporozoites of a parasite line carrying mutations in this domain cannot translate force production and retrograde flow into optimal parasite motility. Using molecular dynamics simulations, we find that differences between mutant parasites in their capacity to migrate can be traced back to a single hydrogen bond at the actin-profilin interface.
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Affiliation(s)
- Catherine A. Moreau
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
| | - Saligram P. Bhargav
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Hirdesh Kumar
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), Heidelberg, Germany
| | - Katharina A. Quadt
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
- Institute for Physical Chemistry, Biophysical Chemistry, Heidelberg University, Heidelberg, Germany
| | - Henni Piirainen
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Léanne Strauss
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
| | - Jessica Kehrer
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
| | - Martin Streichfuss
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
- Institute for Physical Chemistry, Biophysical Chemistry, Heidelberg University, Heidelberg, Germany
| | - Joachim P. Spatz
- Institute for Physical Chemistry, Biophysical Chemistry, Heidelberg University, Heidelberg, Germany
- Department of Cellular Biophysics, Max-Planck Institute for Medical Research, Heidelberg, Germany
| | - Rebecca C. Wade
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), Heidelberg, Germany
- Center for Molecular Biology (ZMBH), DKFZ-ZMBH Alliance and Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Heidelberg, Germany
| | - Inari Kursula
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
- Department of Biomedicine, University of Bergen, Bergen, Norway
- * E-mail: (IK); (FF)
| | - Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
- * E-mail: (IK); (FF)
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Abstract
Early electron microscopy studies revealed the elaborate cellular features that define the unique adaptations of apicomplexan parasites. Among these were bulbous rhoptry (ROP) organelles and small, dense granules (GRAs), both of which are secreted during invasion of host cells. These early morphological studies were followed by the exploration of the cellular contents of these secretory organelles, revealing them to be comprised of highly divergent protein families with few conserved domains or predicted functions. In parallel, studies on host-pathogen interactions identified many host signaling pathways that were mysteriously altered by infection. It was only with the advent of forward and reverse genetic strategies that the connections between individual parasite effectors and the specific host pathways that they targeted finally became clear. The current repertoire of parasite effectors includes ROP kinases and pseudokinases that are secreted during invasion and that block host immune pathways. Similarly, many secretory GRA proteins alter host gene expression by activating host transcription factors, through modification of chromatin, or by inducing small noncoding RNAs. These effectors highlight novel mechanisms by which T. gondii has learned to harness host signaling to favor intracellular survival and will guide future studies designed to uncover the additional complexity of this intricate host-pathogen interaction.
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75
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Calmodulin-like proteins localized to the conoid regulate motility and cell invasion by Toxoplasma gondii. PLoS Pathog 2017; 13:e1006379. [PMID: 28475612 PMCID: PMC5435356 DOI: 10.1371/journal.ppat.1006379] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 05/17/2017] [Accepted: 04/26/2017] [Indexed: 01/09/2023] Open
Abstract
Toxoplasma gondii contains an expanded number of calmodulin (CaM)-like proteins whose functions are poorly understood. Using a combination of CRISPR/Cas9-mediated gene editing and a plant-like auxin-induced degron (AID) system, we examined the roles of three apically localized CaMs. CaM1 and CaM2 were individually dispensable, but loss of both resulted in a synthetic lethal phenotype. CaM3 was refractory to deletion, suggesting it is essential. Consistent with this prediction auxin-induced degradation of CaM3 blocked growth. Phenotypic analysis revealed that all three CaMs contribute to parasite motility, invasion, and egress from host cells, and that they act downstream of microneme and rhoptry secretion. Super-resolution microscopy localized all three CaMs to the conoid where they overlap with myosin H (MyoH), a motor protein that is required for invasion. Biotinylation using BirA fusions with the CaMs labeled a number of apical proteins including MyoH and its light chain MLC7, suggesting they may interact. Consistent with this hypothesis, disruption of MyoH led to degradation of CaM3, or redistribution of CaM1 and CaM2. Collectively, our findings suggest these CaMs may interact with MyoH to control motility and cell invasion. One of the most common motifs that binds calcium to transduce intracellular signals is called an EF hand- named after the globular domain structure first characterized in ovalbumin. A conserved cluster of four EF hands, each of which that binds one calcium atom, is a conserved feature of calmodulin, centrins, and calmodulin-like proteins, including myosin light chains. Although the presence of EF hands is predictive of calcium binding, it alone does not allow classification of biological function as this set of conserved proteins have very diverse functions. Here we used modified editing procedures based on CRISPR/Cas9 combined with a plant-like degradation system to define the roles of three calmodulin-like proteins in T. gondii. These proteins all localized to a specialized apical structure called the conoid where they overlap with the motor protein called MyoH. Additionally, biochemical and genetic studies suggest they coordinately regulate cell invasion. These new genomic editing tools, combined with an efficient system for protein degradation, expand the functional tool kit for an analysis of essential genes and proteins in T. gondii.
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76
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Abstract
Cyclic GMP (cGMP)-dependent protein kinase (protein kinase G [PKG]) is essential for microneme secretion, motility, invasion, and egress in apicomplexan parasites, However, the separate roles of two isoforms of the kinase that are expressed by some apicomplexans remain uncertain. Despite having identical regulatory and catalytic domains, PKGI is plasma membrane associated whereas PKGII is cytosolic in Toxoplasma gondii. To determine whether these isoforms are functionally distinct or redundant, we developed an auxin-inducible degron (AID) tagging system for conditional protein depletion in T. gondii. By combining AID regulation with genome editing strategies, we determined that PKGI is necessary and fully sufficient for PKG-dependent cellular processes. Conversely, PKGII is functionally insufficient and dispensable in the presence of PKGI. The difference in functionality mapped to the first 15 residues of PKGI, containing a myristoylated Gly residue at position 2 that is critical for membrane association and PKG function. Collectively, we have identified a novel requirement for cGMP signaling at the plasma membrane and developed a new system for examining essential proteins in T. gondii. Toxoplasma gondii is an obligate intracellular apicomplexan parasite and important clinical and veterinary pathogen that causes toxoplasmosis. Since apicomplexans can only propagate within host cells, efficient invasion is critically important for their life cycles. Previous studies using chemical genetics demonstrated that cyclic GMP signaling through protein kinase G (PKG)-controlled invasion by apicomplexan parasites. However, these studies did not resolve functional differences between two compartmentalized isoforms of the kinase. Here we developed a conditional protein regulation tool to interrogate PKG isoforms in T. gondii. We found that the cytosolic PKG isoform was largely insufficient and dispensable. In contrast, the plasma membrane-associated isoform was necessary and fully sufficient for PKG function. Our studies identify the plasma membrane as a key location for PKG activity and provide a broadly applicable system for examining essential proteins in T. gondii.
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77
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Niu YQ, He T, Song J, Chen SP, Liu XY, Chen ZG, Yu YJ, Chen SG. A new AIE multi-block polyurethane copolymer material for subcellular microfilament imaging in living cells. Chem Commun (Camb) 2017. [DOI: 10.1039/c7cc02555f] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A multi-block fluorescent amphiphilic polyurethane copolymer (TPE-PU), self-assembling into hairy, water-soluble micelles, is used as a subcellular microfilament probe in living cells.
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Affiliation(s)
- Yu-qing Niu
- Nanshan District Key Lab for Biopolymers and Safety Evaluation
- Shenzhen Key Laboratory of Polymer Science and Technology
- Guangdong Research Center for Interfacial Engineering of Functional Materials
- College of Materials Science and Engineering
- Shenzhen University
| | - Tao He
- Multidisciplinary Research Center
- Shantou University
- Shantou
- China
| | - Jun Song
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province
- College of Optoelectronic Engineering
- Shenzhen University
- Shenzhen 518060
- P. R. China
| | - Si-ping Chen
- Shenzhen University Health Science Center
- Shenzhen 518060
- P. R. China
| | - Xiang-yu Liu
- Nanshan District Key Lab for Biopolymers and Safety Evaluation
- Shenzhen Key Laboratory of Polymer Science and Technology
- Guangdong Research Center for Interfacial Engineering of Functional Materials
- College of Materials Science and Engineering
- Shenzhen University
| | - Zhi-gang Chen
- Nanshan District Key Lab for Biopolymers and Safety Evaluation
- Shenzhen Key Laboratory of Polymer Science and Technology
- Guangdong Research Center for Interfacial Engineering of Functional Materials
- College of Materials Science and Engineering
- Shenzhen University
| | - Ying-jie Yu
- Department of Materials Science and Engineering
- Stony Brook University
- Stony Brook
- USA
| | - Shi-guo Chen
- Nanshan District Key Lab for Biopolymers and Safety Evaluation
- Shenzhen Key Laboratory of Polymer Science and Technology
- Guangdong Research Center for Interfacial Engineering of Functional Materials
- College of Materials Science and Engineering
- Shenzhen University
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