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Walzer KA, Tandel J, Byerly JH, Daniels AM, Gullicksrud JA, Whelan EC, Carro SD, Krespan E, Beiting DP, Striepen B. Transcriptional control of the Cryptosporidium life cycle. Nature 2024; 630:174-180. [PMID: 38811723 DOI: 10.1038/s41586-024-07466-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 04/25/2024] [Indexed: 05/31/2024]
Abstract
The parasite Cryptosporidium is a leading agent of diarrhoeal disease in young children, and a cause and consequence of chronic malnutrition1,2. There are no vaccines and only limited treatment options3. The parasite infects enterocytes, in which it engages in asexual and sexual replication4, both of which are essential to continued infection and transmission. However, their molecular mechanisms remain largely unclear5. Here we use single-cell RNA sequencing to reveal the gene expression programme of the entire Cryptosporidium parvum life cycle in culture and in infected animals. Diverging from the prevailing model6, we find support for only three intracellular stages: asexual type-I meronts, male gamonts and female gametes. We reveal a highly organized program for the assembly of components at each stage. Dissecting the underlying regulatory network, we identify the transcription factor Myb-M as the earliest determinant of male fate, in an organism that lacks genetic sex determination. Conditional expression of this factor overrides the developmental program and induces widespread maleness, while conditional deletion ablates male development. Both have a profound impact on the infection. A large set of stage-specific genes now provides the opportunity to understand, engineer and disrupt parasite sex and life cycle progression to advance the development of vaccines and treatments.
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Affiliation(s)
- Katelyn A Walzer
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jayesh Tandel
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jessica H Byerly
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Abigail M Daniels
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jodi A Gullicksrud
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Eoin C Whelan
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Stephen D Carro
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Elise Krespan
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Daniel P Beiting
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Boris Striepen
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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2
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Katelas DA, Cruz-Miron R, Arroyo-Olarte RD, Brouwers JF, Srivastav RK, Gupta N. Phosphatidylserine synthase in the endoplasmic reticulum of Toxoplasma is essential for its lytic cycle in human cells. J Lipid Res 2024; 65:100535. [PMID: 38522751 PMCID: PMC11166882 DOI: 10.1016/j.jlr.2024.100535] [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: 09/15/2023] [Revised: 03/04/2024] [Accepted: 03/18/2024] [Indexed: 03/26/2024] Open
Abstract
Glycerophospholipids have emerged as a significant contributor to the intracellular growth of pathogenic protist Toxoplasma gondii. Phosphatidylserine (PtdSer) is one such lipid, attributed to the locomotion and motility-dependent invasion and egress events in its acutely infectious tachyzoite stage. However, the de novo synthesis of PtdSer and the importance of the pathway in tachyzoites remain poorly understood. We show that a base-exchange-type PtdSer synthase (PSS) located in the parasite's endoplasmic reticulum produces PtdSer, which is rapidly converted to phosphatidylethanolamine (PtdEtn) by PtdSer decarboxylase (PSD) activity. The PSS-PSD pathway enables the synthesis of several lipid species, including PtdSer (16:0/18:1) and PtdEtn (18:2/20:4, 18:1/18:2 and 18:2/22:5). The PSS-depleted strain exhibited a lower abundance of the major ester-linked PtdEtn species and concurrent accrual of host-derived ether-PtdEtn species. Most phosphatidylthreonine (PtdThr) species-an exclusive natural analog of PtdSer, also made in the endoplasmic reticulum-were repressed. PtdSer species, however, remained largely unaltered, likely due to the serine-exchange reaction of PtdThr synthase in favor of PtdSer upon PSS depletion. Not least, the loss of PSS abrogated the lytic cycle of tachyzoites, impairing the cell division, motility, and egress. In a nutshell, our data demonstrate a critical role of PSS in the biogenesis of PtdSer and PtdEtn species and its physiologically essential repurposing for the asexual reproduction of a clinically relevant intracellular pathogen.
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Affiliation(s)
- Dimitrios Alexandros Katelas
- Department of Molecular Parasitology, Faculty of Life Sciences, Humboldt University, Berlin, Germany; Intracellular Parasite Education and Research Labs (iPEARL), Department of Biological Sciences, Birla Institute of Technology and Science, Pilani (BITS-Pilani), Hyderabad, India
| | - Rosalba Cruz-Miron
- Department of Molecular Parasitology, Faculty of Life Sciences, Humboldt University, Berlin, Germany; Intracellular Parasite Education and Research Labs (iPEARL), Department of Biological Sciences, Birla Institute of Technology and Science, Pilani (BITS-Pilani), Hyderabad, India
| | - Ruben D Arroyo-Olarte
- Department of Molecular Parasitology, Faculty of Life Sciences, Humboldt University, Berlin, Germany; Carrera de Médico Cirujano y Unidad de Biomedicina (UBIMED), FES-Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla, Mexico
| | - Jos F Brouwers
- Analysis Techniques in the Life Sciences, Centre of Expertise Perspective in Health, Avans University of Applied Sciences, Breda, The Netherlands
| | - Ratnesh Kumar Srivastav
- Intracellular Parasite Education and Research Labs (iPEARL), Department of Biological Sciences, Birla Institute of Technology and Science, Pilani (BITS-Pilani), Hyderabad, India
| | - Nishith Gupta
- Department of Molecular Parasitology, Faculty of Life Sciences, Humboldt University, Berlin, Germany; Intracellular Parasite Education and Research Labs (iPEARL), Department of Biological Sciences, Birla Institute of Technology and Science, Pilani (BITS-Pilani), Hyderabad, India.
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3
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Quan JJ, Nikolov LA, Sha J, Wohlschlegel JA, Coppens I, Bradley PJ. Systematic characterization of all Toxoplasma gondii TBC domain-containing proteins identifies an essential regulator of Rab2 in the secretory pathway. PLoS Biol 2024; 22:e3002634. [PMID: 38713739 PMCID: PMC11101121 DOI: 10.1371/journal.pbio.3002634] [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: 06/04/2023] [Revised: 05/17/2024] [Accepted: 04/22/2024] [Indexed: 05/09/2024] Open
Abstract
Toxoplasma gondii resides in its intracellular niche by employing a series of specialized secretory organelles that play roles in invasion, host cell manipulation, and parasite replication. Rab GTPases are major regulators of the parasite's secretory traffic that function as nucleotide-dependent molecular switches to control vesicle trafficking. While many of the Rab proteins have been characterized in T. gondii, precisely how these Rabs are regulated remains poorly understood. To better understand the parasite's secretory traffic, we investigated the entire family of Tre2-Bub2-Cdc16 (TBC) domain-containing proteins, which are known to be involved in vesicle fusion and secretory protein trafficking. We first determined the localization of all 18 TBC domain-containing proteins to discrete regions of the secretory pathway or other vesicles in the parasite. Second, we use an auxin-inducible degron approach to demonstrate that the protozoan-specific TgTBC9 protein, which localizes to the endoplasmic reticulum (ER), is essential for parasite survival. Knockdown of TgTBC9 results in parasite growth arrest and affects the organization of the ER and mitochondrial morphology. TgTBC9 knockdown also results in the formation of large lipid droplets (LDs) and multi-membranous structures surrounded by ER membranes, further indicating a disruption of ER functions. We show that the conserved dual-finger active site in the TBC domain of the protein is critical for its GTPase-activating protein (GAP) function and that the Plasmodium falciparum orthologue of TgTBC9 can rescue the lethal knockdown. We additionally show by immunoprecipitation and yeast 2 hybrid analyses that TgTBC9 preferentially binds Rab2, indicating that the TBC9-Rab2 pair controls ER morphology and vesicular trafficking in the parasite. Together, these studies identify the first essential TBC protein described in any protozoan and provide new insight into intracellular vesicle trafficking in T. gondii.
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Affiliation(s)
- Justin J. Quan
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Lachezar A. Nikolov
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Jihui Sha
- Department of Biological Chemistry and Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - James A. Wohlschlegel
- Department of Biological Chemistry and Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Peter J. Bradley
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, United States of America
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4
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Jimenéz-Ruiz E, Li W, Meissner M. Where is the EXIT? Phenotypic screens for new egress factors in apicomplexan parasites. Mol Microbiol 2024; 121:359-367. [PMID: 37740453 DOI: 10.1111/mmi.15166] [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: 06/23/2023] [Revised: 08/31/2023] [Accepted: 09/05/2023] [Indexed: 09/24/2023]
Abstract
Apicomplexans, such as Plasmodium and Toxoplasma are obligate intracellular parasites that invade, replicate and finally EXIT their host cell. During replication within a parasitophorous vacuole (PV), the parasites establish an extensive F-actin-containing network that connects individual parasites and is required for material exchange, recycling and the final steps of daughter cell assembly. After multiple rounds of replication, the parasites exit the host cell involving multiple signalling cascades, disassembly of the network, secretion of microneme proteins and activation of the acto-myosin motor. Blocking the host cell EXIT process leads to the formation of large PVs, making the screening for genes involved in exiting the cell relatively straightforward. Given that apicomplexans are highly diverse from other eukaryotes, approximately 30% of all genes are annotated as hypothetical, some apicomplexan-specific factors are likely to be critical during EXIT. This motivated several labs to design and perform forward genetic and phenotypic screens using various approaches, such as random insertion mutagenesis, temperature-sensitive mutants and, more recently, CRISPR/Cas9-mediated targeted editing and conditional mutagenesis. Here we will provide an overview of the technological developments over recent years and the most successful stories that led to the identification of new critical factors in Toxoplasma gondii.
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Affiliation(s)
- Elena Jimenéz-Ruiz
- Experimental Parasitology, Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität, LMU, Munich, Germany
| | - Wei Li
- Experimental Parasitology, Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität, LMU, Munich, Germany
| | - Markus Meissner
- Experimental Parasitology, Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität, LMU, Munich, Germany
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5
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Abdeeva IA, Panina YS, Maloshenok LG. Synthetic Biology Approaches to Posttranslational Regulation in Plants. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:S278-S289. [PMID: 38621756 DOI: 10.1134/s0006297924140165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/10/2023] [Accepted: 10/16/2023] [Indexed: 04/17/2024]
Abstract
To date synthetic biology approaches involving creation of functional genetic modules are used in a wide range of organisms. In plants, such approaches are used both for research in the field of functional genomics and to increase the yield of agricultural crops. Of particular interest are methods that allow controlling genetic apparatus of the plants at post-translational level, which allow reducing non-targeted effects from interference with the plant genome. This review discusses recent advances in the plant synthetic biology for regulation of the plant metabolism at posttranslational level and highlights their future directions.
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Affiliation(s)
- Inna A Abdeeva
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, 119991, Russia.
| | - Yulia S Panina
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Liliya G Maloshenok
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, 119991, Russia.
- Bach Institute of Biochemistry, Federal Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
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6
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Etersque JM, Lee IK, Sharma N, Xu K, Ruff A, Northrup JD, Sarkar S, Nguyen T, Lauman R, Burslem GM, Sellmyer MA. Regulation of eDHFR-tagged proteins with trimethoprim PROTACs. Nat Commun 2023; 14:7071. [PMID: 37923771 PMCID: PMC10624689 DOI: 10.1038/s41467-023-42820-3] [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: 02/07/2023] [Accepted: 10/22/2023] [Indexed: 11/06/2023] Open
Abstract
Temporal control of protein levels in cells and living animals can be used to improve our understanding of protein function. In addition, control of engineered proteins could be used in therapeutic applications. PRoteolysis-TArgeting Chimeras (PROTACs) have emerged as a small-molecule-driven strategy to achieve rapid, post-translational regulation of protein abundance via recruitment of an E3 ligase to the target protein of interest. Here, we develop several PROTAC molecules by covalently linking the antibiotic trimethoprim (TMP) to pomalidomide, a ligand for the E3 ligase, Cereblon. These molecules induce degradation of proteins of interest (POIs) genetically fused to a small protein domain, E. coli dihydrofolate reductase (eDHFR), the molecular target of TMP. We show that various eDHFR-tagged proteins can be robustly degraded to 95% of maximum expression with PROTAC molecule 7c. Moreover, TMP-based PROTACs minimally affect the expression of immunomodulatory imide drug (IMiD)-sensitive neosubstrates using proteomic and biochemical assays. Finally, we show multiplexed regulation with another known degron-PROTAC pair, as well as reversible protein regulation in a rodent model of metastatic cancer, demonstrating the formidable strength of this system. Altogether, TMP PROTACs are a robust approach for selective and reversible degradation of eDHFR-tagged proteins in vitro and in vivo.
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Affiliation(s)
- Jean M Etersque
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Iris K Lee
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Nitika Sharma
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kexiang Xu
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Andrew Ruff
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Justin D Northrup
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Swarbhanu Sarkar
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Tommy Nguyen
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Richard Lauman
- The Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - George M Burslem
- The Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- The Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Mark A Sellmyer
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- The Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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7
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Aghabi D, Sloan M, Gill G, Hartmann E, Antipova O, Dou Z, Guerra AJ, Carruthers VB, Harding CR. The vacuolar iron transporter mediates iron detoxification in Toxoplasma gondii. Nat Commun 2023; 14:3659. [PMID: 37339985 PMCID: PMC10281983 DOI: 10.1038/s41467-023-39436-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 06/13/2023] [Indexed: 06/22/2023] Open
Abstract
Iron is essential to cells as a cofactor in enzymes of respiration and replication, however without correct storage, iron leads to the formation of dangerous oxygen radicals. In yeast and plants, iron is transported into a membrane-bound vacuole by the vacuolar iron transporter (VIT). This transporter is conserved in the apicomplexan family of obligate intracellular parasites, including in Toxoplasma gondii. Here, we assess the role of VIT and iron storage in T. gondii. By deleting VIT, we find a slight growth defect in vitro, and iron hypersensitivity, confirming its essential role in parasite iron detoxification, which can be rescued by scavenging of oxygen radicals. We show VIT expression is regulated by iron at transcript and protein levels, and by altering VIT localization. In the absence of VIT, T. gondii responds by altering expression of iron metabolism genes and by increasing antioxidant protein catalase activity. We also show that iron detoxification has an important role both in parasite survival within macrophages and in virulence in a mouse model. Together, by demonstrating a critical role for VIT during iron detoxification in T. gondii, we reveal the importance of iron storage in the parasite and provide the first insight into the machinery involved.
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Affiliation(s)
- Dana Aghabi
- Wellcome Centre of Integrative Parasitology, School of Infection and Immunity, University of Glasgow, Glasgow, UK
| | - Megan Sloan
- Wellcome Centre of Integrative Parasitology, School of Infection and Immunity, University of Glasgow, Glasgow, UK
| | - Grace Gill
- Wellcome Centre of Integrative Parasitology, School of Infection and Immunity, University of Glasgow, Glasgow, UK
| | - Elena Hartmann
- Wellcome Centre of Integrative Parasitology, School of Infection and Immunity, University of Glasgow, Glasgow, UK
| | - Olga Antipova
- X-Ray Sciences Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL, USA
| | - Zhicheng Dou
- Department of Biological Sciences, Clemson University, Clemson, SC, USA
| | - Alfredo J Guerra
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
- Cayman Chemical Company, Ann Arbor, MI, USA
| | - Vern B Carruthers
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Clare R Harding
- Wellcome Centre of Integrative Parasitology, School of Infection and Immunity, University of Glasgow, Glasgow, UK.
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8
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Tandel J, Walzer KA, Byerly JH, Pinkston B, Beiting DP, Striepen B. Genetic Ablation of a Female-Specific Apetala 2 Transcription Factor Blocks Oocyst Shedding in Cryptosporidium parvum. mBio 2023; 14:e0326122. [PMID: 36786597 PMCID: PMC10233709 DOI: 10.1128/mbio.03261-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 01/26/2023] [Indexed: 02/15/2023] Open
Abstract
The apicomplexan parasite Cryptosporidium is a leading global cause of diarrheal disease, and the infection poses a particularly grave threat to young children and those with weakened immune function. Infection occurs by ingestion of meiotic spores called oocysts, and transmission relies on fecal shedding of new oocysts. The entire life cycle thus occurs in a single host and features asexual as well as sexual forms of replication. Here, we identify and locus tag two Apetala 2-type (AP2) transcription factors and demonstrate that they are exclusively expressed in male and female gametes, respectively. To enable functional studies of essential genes in Cryptosporidium parvum, we develop and validate a small-molecule-inducible gene excision system, which we apply to the female factor AP2-F to achieve conditional gene knockout. Analyzing this mutant, we find the factor to be dispensable for asexual growth and early female fate determination in vitro but to be required for oocyst shedding in infected animals in vivo. Transcriptional analyses conducted in the presence or absence of AP2-F revealed that the factor controls the transcription of genes encoding crystalloid body proteins, which are exclusively expressed in female gametes. In C. parvum, the organelle is restricted to sporozoites, and its loss in other apicomplexan parasites leads to blocked transmission. Overall, our development of conditional gene ablation in C. parvum provides a robust method for genetic analysis in this parasite that enabled us to identify AP2-F as an essential regulator of transcription required for oocyst shedding and transmission. IMPORTANCE The parasite Cryptosporidium infects millions of people worldwide each year, leading to life-threatening diarrheal disease in young children and immunosuppressed individuals. There is no vaccine and only limited treatment. Transmission occurs via the fecal-oral route by an environmentally resilient spore-like oocyst. Infection takes place in the intestinal epithelium, where parasites initially propagate asexually before transitioning to male and female gametes, with sex leading to the formation of new oocysts. The essential role of sexual development for continuous infection and transmission makes it an attractive target for therapy and prevention. To study essential genes and potential drug targets across the life cycle, we established inducible gene excision for C. parvum. We determined that the female-specific transcription factor AP2-F is not required for asexual growth and early female development in vitro but is necessary for oocyst shedding in vivo. This work enhances the genetic tools available to study Cryptosporidium gene function.
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Affiliation(s)
- Jayesh Tandel
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Katelyn A. Walzer
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jessica H. Byerly
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Brittain Pinkston
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Daniel P. Beiting
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Boris Striepen
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
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9
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Delgado ILS, Tavares A, Francisco S, Santos D, Coelho J, Basto AP, Zúquete S, Müller J, Hemphill A, Meissner M, Soares H, Leitão A, Nolasco S. Characterization of a MOB1 Homolog in the Apicomplexan Parasite Toxoplasma gondii. BIOLOGY 2021; 10:biology10121233. [PMID: 34943148 PMCID: PMC8698288 DOI: 10.3390/biology10121233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/19/2021] [Accepted: 11/23/2021] [Indexed: 01/11/2023]
Abstract
Simple Summary Monopolar spindle One Binder1 (MOB1) proteins regulate key cellular functions, namely cell multiplication and cell division. The unicellular parasite Toxoplasma gondii transitions between several morphological stages, with the need to control the number of parasites in its cellular environment. We hypothesized that MOB1 proteins could participate in the regulation of the T. gondii life cycle, having identified one MOB1 protein (TgMOB1) coded in its genome. However, this study shows that TgMOB1 presents divergent features. While in organisms studied to date the lack of MOB1 has led to cell division defects, this did not occur in T. gondii in vitro cultures where mob1 was not an essential gene. Additionally, the identification of TgMOB1 proximity interacting partners detected novel MOB1 interactors. Still, TgMOB1 localizes to the region between the new-forming nuclei during cell division, and T. gondii parasites multiply slower with TgMOB1 overexpression and faster when there is a lack of TgMOB1, indicating an intricate role for TgMOB1 in T. gondii. This study uncovers new features of the T. gondii biology, a zoonotic parasite and model organism for the phylum Apicomplexa, and highlights the complex roles MOB1 proteins may assume, with possible implications for disease processes. Abstract Monopolar spindle One Binder1 (MOB1) proteins are conserved components of the tumor-suppressing Hippo pathway, regulating cellular processes such as cytokinesis. Apicomplexan parasites present a life cycle that relies on the parasites’ ability to differentiate between stages and regulate their proliferation; thus, Hippo signaling pathways could play an important role in the regulation of the apicomplexan life cycle. Here, we report the identification of one MOB1 protein in the apicomplexan Toxoplasma gondii. To characterize the function of MOB1, we generated gain-of-function transgenic lines with a ligand-controlled destabilization domain, and loss-of-function clonal lines obtained through CRISPR/Cas9 technology. Contrary to what has been characterized in other eukaryotes, MOB1 is not essential for cytokinesis in T. gondii. However, this picture is complex since we found MOB1 localized between the newly individualized daughter nuclei at the end of mitosis. Moreover, we detected a significant delay in the replication of overexpressing tachyzoites, contrasting with increased replication rates in knockout tachyzoites. Finally, using the proximity-biotinylation method, BioID, we identified novel members of the MOB1 interactome, a probable consequence of the observed lack of conservation of some key amino acid residues. Altogether, the results point to a complex evolutionary history of MOB1 roles in apicomplexans, sharing properties with other eukaryotes but also with divergent features, possibly associated with their complex life cycle.
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Affiliation(s)
- Inês L. S. Delgado
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
- Faculdade de Medicina Veterinária, Universidade Lusófona, 1749-024 Lisboa, Portugal
| | - Alexandra Tavares
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
| | - Samuel Francisco
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
| | - Dulce Santos
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
| | - João Coelho
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
| | - Afonso P. Basto
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
| | - Sara Zúquete
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
| | - Joachim Müller
- Institute of Parasitology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, CH-3012 Bern, Switzerland; (J.M.); (A.H.)
| | - Andrew Hemphill
- Institute of Parasitology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, CH-3012 Bern, Switzerland; (J.M.); (A.H.)
| | - Markus Meissner
- Institute for Experimental Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität Munich, D-82152 Munich, Germany;
| | - Helena Soares
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, 1990-096 Lisboa, Portugal; or
- Centro de Química Estrutural–Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Alexandre Leitão
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
| | - Sofia Nolasco
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, 1990-096 Lisboa, Portugal; or
- Correspondence: or
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10
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Courtney TM, Darrah KE, Horst TJ, Tsang M, Deiters A. Blue Light Activated Rapamycin for Optical Control of Protein Dimerization in Cells and Zebrafish Embryos. ACS Chem Biol 2021; 16:2434-2443. [PMID: 34609839 DOI: 10.1021/acschembio.1c00547] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Rapamycin-induced dimerization of FKBP and FRB is the most commonly utilized chemically induced protein dimerization system. It has been extensively used to conditionally control protein localization, split-enzyme activity, and protein-protein interactions in general by simply fusing FKBP and FRB to proteins of interest. We have developed a new aminonitrobiphenylethyl caging group and applied it to the generation of a caged rapamycin analog that can be photoactivated using blue light. Importantly, the caged rapamycin analog shows minimal background activity with regard to protein dimerization and can be directly interfaced with a wide range of established (and often commercially available) FKBP/FRB systems. We have successfully demonstrated its applicability to the optical control of enzymatic function, protein stability, and protein subcellular localization. Further, we also showcased its applicability toward optical regulation of cell signaling, specifically mTOR signaling, in cells and aquatic embryos.
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Affiliation(s)
- Taylor M. Courtney
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Kristie E. Darrah
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Trevor J. Horst
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Michael Tsang
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Alexander Deiters
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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11
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Markus BM, Boydston EA, Lourido S. CRISPR-Mediated Transcriptional Repression in Toxoplasma gondii. mSphere 2021; 6:e0047421. [PMID: 34643425 PMCID: PMC8513686 DOI: 10.1128/msphere.00474-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 09/23/2021] [Indexed: 11/20/2022] Open
Abstract
Tools for tuning endogenous gene expression are key to determining the genetic basis of diverse cellular phenotypes. Although synthetic regulatable promoters are available in Toxoplasma, scalable methods for targeted and combinatorial downregulation of gene expression-like RNA interference-have yet to be developed. To investigate the feasibility of CRISPR-mediated transcriptional regulation, we examined the function of two catalytically inactive Cas9 (dCas9) orthologs, from Streptococcus pyogenes and Streptococcus thermophilus, in Toxoplasma. Following the addition of single-guide RNAs (sgRNAs) targeting the promoter and 5' untranslated region (UTR) of the surface antigen gene SAG1, we profiled changes in protein abundance of targeted genes by flow cytometry for transcriptional reporters and immunoblotting. We found that the dCas9 orthologs generated a range of target gene expression levels, and the degree of repression was durable and stably inherited. Therefore, S. pyogenes and S. thermophilus dCas9 can effectively produce intermediate levels of gene expression in Toxoplasma. The distinct sgRNA scaffold requirements of the two dCas9s permit their orthogonal use for simultaneous examination of two distinct loci through transcriptional modulation, labeling for microscopy-based studies, or other dCas9-based approaches. Taking advantage of newly available genomic transcription start site data, these tools will aid in the development of new loss-of-function screening approaches in Toxoplasma. IMPORTANCE Toxoplasma gondii is a ubiquitous intracellular parasite of humans and animals that causes life-threatening disease in immunocompromised patients, fetal abnormalities when contracted during gestation, and recurrent eye lesions in some patients. Despite its health implications, about half of the Toxoplasma genome still lacks functional annotation. A particularly powerful tool for the investigation of an organism's cell biology is the modulation of gene expression, which can produce the subtle phenotypes often required for informing gene function. In Toxoplasma, such tools have limited throughput and versatility. Here, we detail the adaptation of a new set of tools based on CRISPR-Cas9, which allows the targeted downregulation of gene expression in Toxoplasma. With its scalability and adaptability to diverse genomic loci, this approach has the potential to greatly accelerate the functional characterization of the Toxoplasma genome.
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Affiliation(s)
- Benedikt M. Markus
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, USA
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | | | - Sebastian Lourido
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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12
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Briquet S, Gissot M, Silvie O. A toolbox for conditional control of gene expression in apicomplexan parasites. Mol Microbiol 2021; 117:618-631. [PMID: 34564906 PMCID: PMC9293482 DOI: 10.1111/mmi.14821] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 01/29/2023]
Abstract
Apicomplexan parasites encompass diverse pathogens for humans and animals, including the causative agents of malaria and toxoplasmosis, Plasmodium spp. and Toxoplasma gondii. Genetic manipulation of these parasites has become central to explore parasite biology, unravel gene function and identify new targets for therapeutic strategies. Tremendous progress has been achieved over the past years with the advent of next generation sequencing and powerful genome editing methods. In particular, various methods for conditional gene expression have been developed in both Plasmodium and Toxoplasma to knockout or knockdown essential genes, or for inducible expression of master developmental regulators or mutant versions of proteins. Conditional gene expression can be achieved at three distinct levels. At the DNA level, inducible site‐specific recombinases allow conditional genome editing. At the RNA level, regulation can be achieved during transcription, using stage‐specific or regulatable promoters, or post‐transcriptionally through alteration of mRNA stability or translation. At the protein level, several systems have been developed for inducible degradation or displacement of a protein of interest. In this review, we provide an overview of current systems for conditional control of gene expression in Plasmodium and Toxoplasma parasites, highlighting the advantages and limitations of each approach.
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Affiliation(s)
- Sylvie Briquet
- INSERM, CNRS, Centre d'Immunologie et des Maladies Infectieuses, Sorbonne Université, Paris, France
| | - Mathieu Gissot
- CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, Center for Infection and Immunity of Lille, CIIL, Univ. Lille, Lille, France
| | - Olivier Silvie
- INSERM, CNRS, Centre d'Immunologie et des Maladies Infectieuses, Sorbonne Université, Paris, France
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13
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López Del Amo V, Leger BS, Cox KJ, Gill S, Bishop AL, Scanlon GD, Walker JA, Gantz VM, Choudhary A. Small-Molecule Control of Super-Mendelian Inheritance in Gene Drives. Cell Rep 2021; 31:107841. [PMID: 32610142 PMCID: PMC7587219 DOI: 10.1016/j.celrep.2020.107841] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/20/2020] [Accepted: 06/09/2020] [Indexed: 11/29/2022] Open
Abstract
Synthetic CRISPR-based gene-drive systems have tremendous potential in public health and agriculture, such as for fighting vector-borne diseases or suppressing crop pest populations. These elements can rapidly spread in a population by breaching the inheritance limit of 50% dictated by Mendel's law of gene segregation, making them a promising tool for population engineering. However, current technologies lack control over their propagation capacity, and there are important concerns about potential unchecked spreading. Here, we describe a gene-drive system in Drosophila that generates an analog inheritance output that can be tightly and conditionally controlled to between 50% and 100%. This technology uses a modified SpCas9 that responds to a synthetic, orally available small molecule, fine-tuning the inheritance probability. This system opens a new avenue to feasibility studies for spatial and temporal control of gene drives using small molecules.
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Affiliation(s)
- Víctor López Del Amo
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Brittany S Leger
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Kurt J Cox
- Chemical Biology and Therapeutics Science, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA; Divisions of Renal Medicine and Engineering, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Shubhroz Gill
- Chemical Biology and Therapeutics Science, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Alena L Bishop
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Garrett D Scanlon
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - James A Walker
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Cancer Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
| | - Valentino M Gantz
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA.
| | - Amit Choudhary
- Chemical Biology and Therapeutics Science, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA; Divisions of Renal Medicine and Engineering, Brigham and Women's Hospital, Boston, MA 02115, USA.
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14
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Dos Santos Pacheco N, Soldati-Favre D. Coupling Auxin-Inducible Degron System with Ultrastructure Expansion Microscopy to Accelerate the Discovery of Gene Function in Toxoplasma gondii. Methods Mol Biol 2021; 2369:121-137. [PMID: 34313987 DOI: 10.1007/978-1-0716-1681-9_8] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Ultrastructure expansion microscopy (U-ExM) is an emerging technique allowing the localization of proteins and cellular structures, at a level of resolution only distinguishable previously via immunoelectron microscopy. U-ExM, as its name indicates, is based on the physical expansion of the sample in the three dimensions without altering its internal features. The proteins of interest are later immunostained for their detection. To accelerate the discovery of gene function in the protozoan parasite Toxoplasma gondii, U-ExM can be coupled to the auxin-inducible degron system (mAiD system). This pipeline led to the subcellular localization of the gene product at unprecedented resolution and simultaneously assessed the consequences of conditional gene disruption. In this chapter, we explain the specific U-ExM protocol used for T. gondii tachyzoite samples and provide non-trivial advice and tips to successfully perform the experiments.
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Affiliation(s)
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva, Switzerland
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15
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Blake TCA, Haase S, Baum J. Actomyosin forces and the energetics of red blood cell invasion by the malaria parasite Plasmodium falciparum. PLoS Pathog 2020; 16:e1009007. [PMID: 33104759 PMCID: PMC7644091 DOI: 10.1371/journal.ppat.1009007] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 11/05/2020] [Accepted: 09/28/2020] [Indexed: 11/29/2022] Open
Abstract
All symptoms of malaria disease are associated with the asexual blood stages of development, involving cycles of red blood cell (RBC) invasion and egress by the Plasmodium spp. merozoite. Merozoite invasion is rapid and is actively powered by a parasite actomyosin motor. The current accepted model for actomyosin force generation envisages arrays of parasite myosins, pushing against short actin filaments connected to the external milieu that drive the merozoite forwards into the RBC. In Plasmodium falciparum, the most virulent human malaria species, Myosin A (PfMyoA) is critical for parasite replication. However, the precise function of PfMyoA in invasion, its regulation, the role of other myosins and overall energetics of invasion remain unclear. Here, we developed a conditional mutagenesis strategy combined with live video microscopy to probe PfMyoA function and that of the auxiliary motor PfMyoB in invasion. By imaging conditional mutants with increasing defects in force production, based on disruption to a key PfMyoA phospho-regulation site, the absence of the PfMyoA essential light chain, or complete motor absence, we define three distinct stages of incomplete RBC invasion. These three defects reveal three energetic barriers to successful entry: RBC deformation (pre-entry), mid-invasion initiation, and completion of internalisation, each requiring an active parasite motor. In defining distinct energetic barriers to invasion, these data illuminate the mechanical challenges faced in this remarkable process of protozoan parasitism, highlighting distinct myosin functions and identifying potential targets for preventing malaria pathogenesis.
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Affiliation(s)
- Thomas C. A. Blake
- Department of Life Sciences, Imperial College London, South Kensington, London, United Kingdom
| | - Silvia Haase
- Department of Life Sciences, Imperial College London, South Kensington, London, United Kingdom
| | - Jake Baum
- Department of Life Sciences, Imperial College London, South Kensington, London, United Kingdom
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16
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Kloehn J, Oppenheim RD, Siddiqui G, De Bock PJ, Kumar Dogga S, Coute Y, Hakimi MA, Creek DJ, Soldati-Favre D. Multi-omics analysis delineates the distinct functions of sub-cellular acetyl-CoA pools in Toxoplasma gondii. BMC Biol 2020; 18:67. [PMID: 32546260 PMCID: PMC7296777 DOI: 10.1186/s12915-020-00791-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 05/08/2020] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Acetyl-CoA is a key molecule in all organisms, implicated in several metabolic pathways as well as in transcriptional regulation and post-translational modification. The human pathogen Toxoplasma gondii possesses at least four enzymes which generate acetyl-CoA in the nucleo-cytosol (acetyl-CoA synthetase (ACS); ATP citrate lyase (ACL)), mitochondrion (branched-chain α-keto acid dehydrogenase-complex (BCKDH)) and apicoplast (pyruvate dehydrogenase complex (PDH)). Given the diverse functions of acetyl-CoA, we know very little about the role of sub-cellular acetyl-CoA pools in parasite physiology. RESULTS To assess the importance and functions of sub-cellular acetyl-CoA-pools, we measured the acetylome, transcriptome, proteome and metabolome of parasites lacking ACL/ACS or BCKDH. We demonstrate that ACL/ACS constitute a synthetic lethal pair. Loss of both enzymes causes a halt in fatty acid elongation, hypo-acetylation of nucleo-cytosolic and secretory proteins and broad changes in gene expression. In contrast, loss of BCKDH results in an altered TCA cycle, hypo-acetylation of mitochondrial proteins and few specific changes in gene expression. We provide evidence that changes in the acetylome, transcriptome and proteome of cells lacking BCKDH enable the metabolic adaptations and thus the survival of these parasites. CONCLUSIONS Using multi-omics and molecular tools, we obtain a global and integrative picture of the role of distinct acetyl-CoA pools in T. gondii physiology. Cytosolic acetyl-CoA is essential and is required for the synthesis of parasite-specific fatty acids. In contrast, loss of mitochondrial acetyl-CoA can be compensated for through metabolic adaptations implemented at the transcriptional, translational and post-translational level.
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Affiliation(s)
- Joachim Kloehn
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Rue Michel-Servet 1, 1211, Geneva, Switzerland
| | - Rebecca D Oppenheim
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Rue Michel-Servet 1, 1211, Geneva, Switzerland
| | - Ghizal Siddiqui
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville campus, Parkville, VIC, 3052, Australia
| | - Pieter-Jan De Bock
- University Grenoble Alpes, CEA, INSERM, IRIG, BGE, F-38000, Grenoble, France
| | - Sunil Kumar Dogga
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Rue Michel-Servet 1, 1211, Geneva, Switzerland
| | - Yohann Coute
- University Grenoble Alpes, CEA, INSERM, IRIG, BGE, F-38000, Grenoble, France
| | - Mohamed-Ali Hakimi
- Epigenetic and Parasites Team, UMR5163/LAPM, Domaine de la Merci, Jean Roget Institute, 38700, La Tronche, France
| | - Darren J Creek
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville campus, Parkville, VIC, 3052, Australia
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Rue Michel-Servet 1, 1211, Geneva, Switzerland.
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17
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Patil H, Hughes KR, Lemgruber L, Philip N, Dickens N, Starnes GL, Waters AP. Zygote morphogenesis but not the establishment of cell polarity in Plasmodium berghei is controlled by the small GTPase, RAB11A. PLoS Pathog 2020; 16:e1008091. [PMID: 32463831 PMCID: PMC7255598 DOI: 10.1371/journal.ppat.1008091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 02/29/2020] [Indexed: 11/19/2022] Open
Abstract
Plasmodium species are apicomplexan parasites whose zoites are polarized cells with a marked apical organisation where the organelles associated with host cell invasion and colonization reside. Plasmodium gametes mate in the mosquito midgut to form the spherical and presumed apolar zygote that morphs during the following 24 hours into a polarized, elongated and motile zoite form, the ookinete. Endocytosis-mediated protein transport is generally necessary for the establishment and maintenance of polarity in epithelial cells and neurons, and the small GTPase RAB11A is an important regulator of protein transport via recycling endosomes. PbRAB11A is essential in blood stage asexual of Plasmodium. Therefore, a promoter swap strategy was employed to down-regulate PbRAB11A expression in gametocytes and zygotes of the rodent malaria parasite, Plasmodium berghei which demonstrated the essential role of RAB11A in ookinete development. The approach revealed that lack of PbRAB11A had no effect on gamete production and fertility rates however, the zygote to ookinete transition was almost totally inhibited and transmission through the mosquito was prevented. Lack of PbRAB11A did not prevent meiosis and mitosis, nor the establishment of polarity as indicated by the correct formation and positioning of the Inner Membrane Complex (IMC) and apical complex. However, morphological maturation was prevented and parasites remained spherical and immotile and furthermore, they were impaired in the secretion and distribution of microneme cargo. The data are consistent with the previously proposed model of RAB11A endosome mediated delivery of plasma membrane in Toxoplasma gondii if not its role in IMC formation and implicate it in microneme function.
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Affiliation(s)
- Harshal Patil
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Katie R. Hughes
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Leandro Lemgruber
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Nisha Philip
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Nicholas Dickens
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - G. Lucas Starnes
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Andrew. P. Waters
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, Scotland, United Kingdom
- * E-mail:
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18
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The Bradyzoite: A Key Developmental Stage for the Persistence and Pathogenesis of Toxoplasmosis. Pathogens 2020; 9:pathogens9030234. [PMID: 32245165 PMCID: PMC7157559 DOI: 10.3390/pathogens9030234] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 03/18/2020] [Accepted: 03/19/2020] [Indexed: 12/19/2022] Open
Abstract
Toxoplasma gondii is a ubiquitous parasitic protist found in a wide variety of hosts, including a large proportion of the human population. Beyond an acute phase which is generally self-limited in immunocompetent individuals, the ability of the parasite to persist as a dormant stage, called bradyzoite, is an important aspect of toxoplasmosis. Not only is this stage not eliminated by current treatments, but it can also reactivate in immunocompromised hosts, leading to a potentially fatal outcome. Yet, despite its critical role in the pathology, the bradyzoite stage is relatively understudied. One main explanation is that it is a considerably challenging model, which essentially has to be derived from in vivo sources. However, recent progress on genetic manipulation and in vitro differentiation models now offers interesting perspectives for tackling key biological questions related to this particularly important developmental stage.
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19
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Hanquier J, Gimeno T, Jeffers V, Sullivan WJ. Evaluating the GCN5b bromodomain as a novel therapeutic target against the parasite Toxoplasma gondii. Exp Parasitol 2020; 211:107868. [PMID: 32119930 PMCID: PMC7483680 DOI: 10.1016/j.exppara.2020.107868] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 02/10/2020] [Accepted: 02/25/2020] [Indexed: 01/02/2023]
Abstract
Toxoplasma gondii is a protozoan parasite of great importance in human and veterinary health. The frontline treatment of antifolates suffers a variety of drawbacks, including toxicity and allergic reactions, underscoring the need to identify novel drug targets for new therapeutics to be developed. We previously showed that the Toxoplasma lysine acetyltransferase (KAT) GCN5b is an essential chromatin remodeling enzyme in the parasite linked to the regulation of gene expression. We have previously established that the KAT domain is a liability that can be targeted in the parasite by compounds like garcinol; here, we investigate the potential of the bromodomain as a targetable element of GCN5b. Bromodomains bind acetylated lysine residues on histones, which helps stabilize the KAT complex at gene promoters. Using an inducible dominant-negative strategy, we found that the GCN5b bromodomain is critical for Toxoplasma viability. We also found that the GCN5-family bromodomain inhibitor, L-Moses, interferes with the ability of the GCN5b bromodomain to associate with acetylated histone residues using an in vitro binding assay. Moreover, L-Moses displays potent activity against Toxoplasma tachyzoites in vitro, which can be overcome if parasites are engineered to over-express GCN5b. Collectively, our data support the GCN5b bromodomain as an attractive target for the development of new therapeutics.
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Affiliation(s)
- Jocelyne Hanquier
- Department of Microbiology & Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Thomas Gimeno
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Victoria Jeffers
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - William J Sullivan
- Department of Microbiology & Immunology, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, IN, USA.
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20
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Deng W, Bates JA, Wei H, Bartoschek MD, Conradt B, Leonhardt H. Tunable light and drug induced depletion of target proteins. Nat Commun 2020; 11:304. [PMID: 31949141 PMCID: PMC6965615 DOI: 10.1038/s41467-019-14160-8] [Citation(s) in RCA: 20] [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: 05/06/2019] [Accepted: 12/12/2019] [Indexed: 12/28/2022] Open
Abstract
Biological processes in development and disease are controlled by the abundance, localization and modification of cellular proteins. We have developed versatile tools based on recombinant E3 ubiquitin ligases that are controlled by light or drug induced heterodimerization for nanobody or DARPin targeted depletion of endogenous proteins in cells and organisms. We use this rapid, tunable and reversible protein depletion for functional studies of essential proteins like PCNA in DNA repair and to investigate the role of CED-3 in apoptosis during Caenorhabditis elegans development. These independent tools can be combined for spatial and temporal depletion of different sets of proteins, can help to distinguish immediate cellular responses from long-term adaptation effects and can facilitate the exploration of complex networks.
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Affiliation(s)
- Wen Deng
- Department of Biology II, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Jack A Bates
- Department of Biology II, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Hai Wei
- Department of Biology II, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Michael D Bartoschek
- Department of Biology II, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Barbara Conradt
- Department of Biology II, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Heinrich Leonhardt
- Department of Biology II, Ludwig-Maximilians-Universität München, Munich, Germany.
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21
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Boothroyd JC. What a Difference 30 Years Makes! A Perspective on Changes in Research Methodologies Used to Study Toxoplasma gondii. Methods Mol Biol 2020; 2071:1-25. [PMID: 31758444 DOI: 10.1007/978-1-4939-9857-9_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Toxoplasma gondii is a remarkable species with a rich cell, developmental, and population biology. It is also sometimes responsible for serious disease in animals and humans and the stages responsible for such disease are relatively easy to study in vitro or in laboratory animal models. As a result of all this, Toxoplasma has become the subject of intense investigation over the last several decades, becoming a model organism for the study of the phylum of which it is a member, Apicomplexa. This has led to an ever-growing number of investigators applying an ever-expanding set of techniques to dissecting how Toxoplasma "ticks" and how it interacts with its many hosts. In this perspective piece I first wind back the clock 30 years and then trace the extraordinary pace of methodologies that have propelled the field forward to where we are today. In keeping with the theme of this collection, I focus almost exclusively on the parasite, rather than host side of the equation. I finish with a few thoughts about where the field might be headed-though if we have learned anything, the only sure prediction is that the pace of technological advance will surely continue to accelerate and the future will give us still undreamed of methods for taking apart (and then putting back together) this amazing organism with all its intricate biology. We have so far surely just scratched the surface.
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Affiliation(s)
- John C Boothroyd
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA.
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Jacot D, Soldati-Favre D. CRISPR/Cas9-Mediated Generation of Tetracycline Repressor-Based Inducible Knockdown in Toxoplasma gondii. Methods Mol Biol 2020; 2071:125-141. [PMID: 31758450 DOI: 10.1007/978-1-4939-9857-9_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The phylum Apicomplexa groups numerous pathogenic protozoan parasites including Plasmodium, the causative agent of malaria, Cryptosporidium which can cause severe gastrointestinal infections, as well as Babesia, Eimeria, and Theileria that account for considerable economic burdens to poultry and cattle industry. Toxoplasma gondii is the most ubiquitous and opportunistic member of this phylum able to infect all warm-blooded animals and responsible for severe disease in immunocompromised individuals and unborn fetuses.Due to its ease of cultivation and genetic tractability T. gondii has served as recipient for the transfer and adaptation of multiple genetic tools developed to control gene expression. In these parasites, a collection of tight conditional systems exists to control gene expression at the levels of transcription, RNA degradation or protein stability. The recent implementation of the CRISPR/Cas9 technology considerably reduces time and effort to generate transgenic parasites and at the same time increases to an ultimate level of precision the editing of the parasite genome. Here, we provide a step-by-step protocol for CRISPR/Cas9-mediated generation of tetracycline repressor-based inducible knockdown in T. gondii.
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Affiliation(s)
- Damien Jacot
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva, Switzerland.
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva, Switzerland
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Leung JM, Liu J, Wetzel LA, Hu K. Centrin2 from the human parasite Toxoplasma gondii is required for its invasion and intracellular replication. J Cell Sci 2019; 132:jcs.228791. [PMID: 31182647 DOI: 10.1242/jcs.228791] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 06/03/2019] [Indexed: 12/24/2022] Open
Abstract
Centrins are EF-hand containing proteins ubiquitously found in eukaryotes and are key components of centrioles/basal bodies as well as certain contractile fibers. We previously identified three centrins in the human parasite Toxoplasma gondii, all of which localized to the centrioles. However, one of them, T. gondii (Tg) Centrin2 (CEN2), is also targeted to structures at the apical and basal ends of the parasite, as well as to annuli at the base of the apical cap of the membrane cortex. The role(s) that CEN2 play in these locations were unknown. Here, we report the functional characterization of CEN2 using a conditional knockdown method that combines transcriptional and protein stability control. The knockdown resulted in an ordered loss of CEN2 from its four compartments, due to differences in incorporation kinetics and structural inheritance over successive generations. This was correlated with a major invasion deficiency at early stages of CEN2 knockdown, and replication defects at later stages. These results indicate that CEN2 is incorporated into multiple cytoskeletal structures to serve distinct functions that are required for parasite survival.
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Affiliation(s)
| | - Jun Liu
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Laura A Wetzel
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Ke Hu
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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Jørgensen FP, Madsen D, Meldal M, Olsen JV, Petersen M, Granhøj J, Bols M. Synthesis of Shld Derivatives, Their Binding to the Destabilizing Domain, and Influence on Protein Accumulation in Transgenic Plants. J Med Chem 2019; 62:5191-5216. [PMID: 31059249 DOI: 10.1021/acs.jmedchem.9b00497] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of 35 analogues of Shld with modifications in the A-residue and the C-residues were prepared and investigated for binding to FKBP and GFP accumulation in transgenic plants. The modifications investigated explored variations that were supposedly inside or outside the receptor binding site with the latter being important by influencing the overall polarity of the compounds in order to improve the absorption in plants. The binding of the new compounds to the destabilizing domain was determined using a fluorescence polarization competition assay, and the GFP expression in engineered Arabidopsis thaliana was studied. The results showed that modifications of the C-building block phenol with acidic, basic, and neutral groups led to better ligands with some being better than Shld in the plant. Generally small, polar substituents showed the best GFP accumulation.
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Affiliation(s)
- Frederik Præstholm Jørgensen
- Departments of Chemistry and Biology , University of Copenhagen , Universitetsparken 5 , 2100 Copenhagen Ø, Denmark
| | - Daniel Madsen
- Departments of Chemistry and Biology , University of Copenhagen , Universitetsparken 5 , 2100 Copenhagen Ø, Denmark
| | - Morten Meldal
- Departments of Chemistry and Biology , University of Copenhagen , Universitetsparken 5 , 2100 Copenhagen Ø, Denmark
| | - Jacob Valdbjørn Olsen
- Departments of Chemistry and Biology , University of Copenhagen , Universitetsparken 5 , 2100 Copenhagen Ø, Denmark
| | - Morten Petersen
- Departments of Chemistry and Biology , University of Copenhagen , Universitetsparken 5 , 2100 Copenhagen Ø, Denmark
| | - Jeppe Granhøj
- Departments of Chemistry and Biology , University of Copenhagen , Universitetsparken 5 , 2100 Copenhagen Ø, Denmark
| | - Mikael Bols
- Departments of Chemistry and Biology , University of Copenhagen , Universitetsparken 5 , 2100 Copenhagen Ø, Denmark
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Melatti C, Pieperhoff M, Lemgruber L, Pohl E, Sheiner L, Meissner M. A unique dynamin-related protein is essential for mitochondrial fission in Toxoplasma gondii. PLoS Pathog 2019; 15:e1007512. [PMID: 30947298 PMCID: PMC6448817 DOI: 10.1371/journal.ppat.1007512] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Accepted: 12/10/2018] [Indexed: 11/19/2022] Open
Abstract
The single mitochondrion of apicomplexan protozoa is thought to be critical for all stages of the life cycle, and is a validated drug target against these important human and veterinary parasites. In contrast to other eukaryotes, replication of the mitochondrion is tightly linked to the cell cycle. A key step in mitochondrial segregation is the fission event, which in many eukaryotes occurs by the action of dynamins constricting the outer membrane of the mitochondria from the cytosolic face. To date, none of the components of the apicomplexan fission machinery have been identified and validated. We identify here a highly divergent, dynamin-related protein (TgDrpC), conserved in apicomplexans as essential for mitochondrial biogenesis and potentially for fission in Toxoplasma gondii. We show that TgDrpC is found adjacent to the mitochondrion, and is localised both at its periphery and at its basal part, where fission is expected to occur. We demonstrate that depletion or dominant negative expression of TgDrpC results in interconnected mitochondria and ultimately in drastic changes in mitochondrial morphology, as well as in parasite death. Intriguingly, we find that the canonical adaptor TgFis1 is not required for mitochondrial fission. The identification of an Apicomplexa-specific enzyme required for mitochondrial biogenesis and essential for parasite growth highlights parasite adaptation. This work paves the way for future drug development targeting TgDrpC, and for the analysis of additional partners involved in this crucial step of apicomplexan multiplication.
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Affiliation(s)
- Carmen Melatti
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, United Kingdom
| | - Manuela Pieperhoff
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, United Kingdom
| | - Leandro Lemgruber
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, United Kingdom
| | - Ehmke Pohl
- Department of Biosciences, & Biophysical Sciences Institute, Durham University, Durham, United Kingdom
| | - Lilach Sheiner
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, United Kingdom
| | - Markus Meissner
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, United Kingdom
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Florimond C, Cordonnier C, Taujale R, van der Wel H, Kannan N, West CM, Blader IJ. A Toxoplasma Prolyl Hydroxylase Mediates Oxygen Stress Responses by Regulating Translation Elongation. mBio 2019; 10:e00234-19. [PMID: 30914506 PMCID: PMC6437050 DOI: 10.1128/mbio.00234-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Accepted: 02/08/2019] [Indexed: 02/08/2023] Open
Abstract
As the protozoan parasite Toxoplasma gondii disseminates through its host, it responds to environmental changes by altering its gene expression, metabolism, and other processes. Oxygen is one variable environmental factor, and properly adapting to changes in oxygen levels is critical to prevent the accumulation of reactive oxygen species and other cytotoxic factors. Thus, oxygen-sensing proteins are important, and among these, 2-oxoglutarate-dependent prolyl hydroxylases are highly conserved throughout evolution. Toxoplasma expresses two such enzymes, TgPHYa, which regulates the SCF-ubiquitin ligase complex, and TgPHYb. To characterize TgPHYb, we created a Toxoplasma strain that conditionally expresses TgPHYb and report that TgPHYb is required for optimal parasite growth under normal growth conditions. However, exposing TgPHYb-depleted parasites to extracellular stress leads to severe decreases in parasite invasion, which is likely due to decreased abundance of parasite adhesins. Adhesin protein abundance is reduced in TgPHYb-depleted parasites as a result of inactivation of the protein synthesis elongation factor eEF2 that is accompanied by decreased rates of translational elongation. In contrast to most other oxygen-sensing proteins that mediate cellular responses to low O2, TgPHYb is specifically required for parasite growth and protein synthesis at high, but not low, O2 tensions as well as resistance to reactive oxygen species. In vivo, reduced TgPHYb expression leads to lower parasite burdens in oxygen-rich tissues. Taken together, these data identify TgPHYb as a sensor of high O2 levels, in contrast to TgPHYa, which supports the parasite at low O2IMPORTANCE Because oxygen plays a key role in the growth of many organisms, cells must know how much oxygen is available. O2-sensing proteins are therefore critical cellular factors, and prolyl hydroxylases are the best-studied type of O2-sensing proteins. In general, prolyl hydroxylases trigger cellular responses to decreased oxygen availability. But, how does a cell react to high levels of oxygen? Using the protozoan parasite Toxoplasma gondii, we discovered a prolyl hydroxylase that allows the parasite to grow at elevated oxygen levels and does so by regulating protein synthesis. Loss of this enzyme also reduces parasite burden in oxygen-rich tissues, indicating that sensing both high and low levels of oxygen impacts the growth and physiology of Toxoplasma.
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Affiliation(s)
- Celia Florimond
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, USA
| | - Charlotte Cordonnier
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, USA
| | - Rahil Taujale
- Institute of Bioinformatics, University of Georgia, Athens, Georgia, USA
| | - Hanke van der Wel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Natarajan Kannan
- Institute of Bioinformatics, University of Georgia, Athens, Georgia, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Christopher M West
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Ira J Blader
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, USA
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Harding CR, Gow M, Kang JH, Shortt E, Manalis SR, Meissner M, Lourido S. Alveolar proteins stabilize cortical microtubules in Toxoplasma gondii. Nat Commun 2019; 10:401. [PMID: 30674885 PMCID: PMC6344517 DOI: 10.1038/s41467-019-08318-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 01/04/2019] [Indexed: 12/21/2022] Open
Abstract
Single-celled protists use elaborate cytoskeletal structures, including arrays of microtubules at the cell periphery, to maintain polarity and rigidity. The obligate intracellular parasite Toxoplasma gondii has unusually stable cortical microtubules beneath the alveoli, a network of flattened membrane vesicles that subtends the plasmalemma. However, anchoring of microtubules along alveolar membranes is not understood. Here, we show that GAPM1a, an integral membrane protein of the alveoli, plays a role in maintaining microtubule stability. Degradation of GAPM1a causes cortical microtubule disorganisation and subsequent depolymerisation. These changes in the cytoskeleton lead to parasites becoming shorter and rounder, which is accompanied by a decrease in cellular volume. Extended GAPM1a depletion leads to severe defects in division, reminiscent of the effect of disrupting other alveolar proteins. We suggest that GAPM proteins link the cortical microtubules to the alveoli and are required to maintain the shape and rigidity of apicomplexan zoites. Cortical microtubules of Toxoplasma gondii are exceptionally stable, but it isn’t known how they are anchored along membranes. Here, Harding et al. show that GAPM proteins localize to the inner membrane complex and are essential for maintaining the structural stability of parasites.
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Affiliation(s)
- Clare R Harding
- Whitehead Institute for Biomedical Research, Cambridge, 02142, MA, USA.
| | - Matthew Gow
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, G12 8TA, UK
| | - Joon Ho Kang
- Department of Physics, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA.,Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA
| | - Emily Shortt
- Whitehead Institute for Biomedical Research, Cambridge, 02142, MA, USA
| | - Scott R Manalis
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA.,Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA
| | - Markus Meissner
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, G12 8TA, UK.,Department of Veterinary Sciences, Ludwig-Maximilians-Universität, Munich, 80539, Germany
| | - Sebastian Lourido
- Whitehead Institute for Biomedical Research, Cambridge, 02142, MA, USA. .,Biology Department, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA.
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Berry L, Chen CT, Francia ME, Guerin A, Graindorge A, Saliou JM, Grandmougin M, Wein S, Bechara C, Morlon-Guyot J, Bordat Y, Gubbels MJ, Lebrun M, Dubremetz JF, Daher W. Toxoplasma gondii chromosomal passenger complex is essential for the organization of a functional mitotic spindle: a prerequisite for productive endodyogeny. Cell Mol Life Sci 2018; 75:4417-4443. [PMID: 30051161 PMCID: PMC6260807 DOI: 10.1007/s00018-018-2889-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 06/28/2018] [Accepted: 07/23/2018] [Indexed: 12/20/2022]
Abstract
The phylum Apicomplexa encompasses deadly pathogens such as malaria and Cryptosporidium. Apicomplexa cell division is mechanistically divergent from that of their mammalian host, potentially representing an attractive source of drug targets. Depending on the species, apicomplexan parasites can modulate the output of cell division, producing two to thousands of daughter cells at once. The inherent flexibility of their cell division mechanisms allows these parasites to adapt to different niches, facilitating their dissemination. Toxoplasma gondii tachyzoites divide using a unique form of cell division called endodyogeny. This process involves a single round of DNA replication, closed nuclear mitosis, and assembly of two daughter cells within a mother. In higher Eukaryotes, the four-subunit chromosomal passenger complex (CPC) (Aurora kinase B (ARKB)/INCENP/Borealin/Survivin) promotes chromosome bi-orientation by detaching incorrect kinetochore-microtubule attachments, playing an essential role in controlling cell division fidelity. Herein, we report the characterization of the Toxoplasma CPC (Aurora kinase 1 (Ark1)/INCENP1/INCENP2). We show that the CPC exhibits dynamic localization in a cell cycle-dependent manner. TgArk1 interacts with both TgINCENPs, with TgINCENP2 being essential for its translocation to the nucleus. While TgINCENP1 appears to be dispensable, interfering with TgArk1 or TgINCENP2 results in pronounced division and growth defects. Significant anti-cancer drug development efforts have focused on targeting human ARKB. Parasite treatment with low doses of hesperadin, a known inhibitor of human ARKB at higher concentrations, phenocopies the TgArk1 and TgINCENP2 mutants. Overall, our study provides new insights into the mechanisms underpinning cell cycle control in Apicomplexa, and highlights TgArk1 as potential drug target.
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Affiliation(s)
- Laurence Berry
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Chun-Ti Chen
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
| | - Maria E Francia
- Molecular Biology Unit, Institut Pasteur de Montevideo, Mataojo 2020, 11400, Montevideo, Uruguay
| | - Amandine Guerin
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM, Université de Montpellier, Montpellier, France
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3800, Spruce Street, Philadelphia, PA, 19104, USA
| | - Arnault Graindorge
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Jean-Michel Saliou
- CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019, UMR 8204, CIIL-Centre d'Infection et d'Immunité de Lille, University of Lille, 59000, Lille, France
| | - Maurane Grandmougin
- CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019, UMR 8204, CIIL-Centre d'Infection et d'Immunité de Lille, University of Lille, 59000, Lille, France
| | - Sharon Wein
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Chérine Bechara
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM, Université de Montpellier, Montpellier, France
- Institut de Génomique Fonctionnelle, CNRS, UMR5230 INSERM U1191, University of Montpellier, 34094, Montpellier, France
| | - Juliette Morlon-Guyot
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Yann Bordat
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Marc-Jan Gubbels
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
| | - Maryse Lebrun
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Jean-François Dubremetz
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Wassim Daher
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM, Université de Montpellier, Montpellier, France.
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Heredero-Bermejo I, Varberg JM, Charvat R, Jacobs K, Garbuz T, Sullivan WJ, Arrizabalaga G. TgDrpC, an atypical dynamin-related protein in Toxoplasma gondii, is associated with vesicular transport factors and parasite division. Mol Microbiol 2018; 111:46-64. [PMID: 30362624 DOI: 10.1111/mmi.14138] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2018] [Indexed: 01/01/2023]
Abstract
Dynamin-related proteins (Drps) are involved in diverse processes such as organelle division and vesicle trafficking. The intracellular parasite Toxoplasma gondii possesses three distinct Drps. TgDrpC, whose function remains unresolved, is unusual in that it lacks a conserved GTPase Effector Domain, which is typically required for function. Here, we show that TgDrpC localizes to cytoplasmic puncta; however, in dividing parasites, TgDrpC redistributes to the growing edge of the daughter cells. By conditional knockdown, we determined that loss of TgDrpC stalls division and leads to rapid deterioration of multiple organelles and the IMC. We also show that TgDrpC interacts with proteins that exhibit homology to those involved in vesicle transport, including members of the adaptor complex 2. Two of these proteins, a homolog of the adaptor protein 2 (AP-2) complex subunit alpha-1 and a homolog of the ezrin-radixin-moesin (ERM) family proteins, localize to puncta and associate with the daughter cells. Consistent with the association with vesicle transport proteins, re-distribution of TgDrpC to the IMC during division is dependent on post-Golgi trafficking. Together, these results support that TgDrpC contributes to vesicle trafficking and is critical for stability of parasite organelles and division.
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Affiliation(s)
- Irene Heredero-Bermejo
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Joseph M Varberg
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Robert Charvat
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Kylie Jacobs
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Tamila Garbuz
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - William J Sullivan
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Gustavo Arrizabalaga
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
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Impact of Engineered Expression of Mitochondrial Association Factor 1b on Toxoplasma gondii Infection and the Host Response in a Mouse Model. mSphere 2018; 3:3/5/e00471-18. [PMID: 30333181 PMCID: PMC6193605 DOI: 10.1128/msphere.00471-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The parasite Toxoplasma gondii currently infects approximately one-third of the world’s population and causes life-threatening toxoplasmosis in individuals with undeveloped or weakened immune systems. Current treatments are unable to cure T. gondii infection, leaving infected individuals with slow-growing tissue cysts for the remainder of their lives. Previous work has shown that expression of the parasite protein mitochondrial association factor 1 (MAF1b) is responsible for the association of T. gondii parasites with host mitochondria and provides a selective advantage during acute infection. Here we examine the impact of MAF1b expression during chronic T. gondii infection. We find that mice infected with MAF1b-expressing parasites have higher cyst burden and cytokine levels than their wild-type counterparts. A better understanding of the genes involved in establishing and maintaining chronic infection will aid in discovering effective therapeutics for chronically infected individuals. The opportunistic intracellular parasite Toxoplasma gondii causes a lifelong chronic infection capable of reactivating in immunocompromised individuals, which can lead to life-threatening complications. Following invasion of the host cell, host mitochondria associate with the parasitophorous vacuole membrane. This phenotype is T. gondii strain specific and is mediated by expression of a host mitochondrial association-competent (HMA+) paralog of the parasite protein mitochondrial association factor 1 (MAF1b). Previous work demonstrated that expression of MAF1b in strains that do not normally associate with host mitochondria increases their fitness during acute infection in vivo. However, the impact of MAF1b expression during chronic T. gondii infection is unclear. In this study, we assess the impact of MAF1b expression on cyst formation and cytokine production in mice. Despite generally low numbers of cysts generated by the in vitro culture-adapted strains used in this study, we find that parasites expressing MAF1b have higher numbers of cysts in the brains of chronically infected mice and that MAF1b+ cyst burden significantly increases during the course of chronic infection. Consistent with this, mice infected with MAF1b+ parasites have higher levels of the serum cytokines RANTES and VEGF (vascular endothelial growth factor) at day 57 postinfection, although this could be due to higher parasite burden at this time point rather than direct manipulation of these cytokines by MAF1b. Overall these data indicate that MAF1b expression may also be important in determining infection outcome during the chronic phase, either by directly altering the cytokine/signaling environment or by increasing proliferation during the acute and/or chronic phase. IMPORTANCE The parasite Toxoplasma gondii currently infects approximately one-third of the world’s population and causes life-threatening toxoplasmosis in individuals with undeveloped or weakened immune systems. Current treatments are unable to cure T. gondii infection, leaving infected individuals with slow-growing tissue cysts for the remainder of their lives. Previous work has shown that expression of the parasite protein mitochondrial association factor 1 (MAF1b) is responsible for the association of T. gondii parasites with host mitochondria and provides a selective advantage during acute infection. Here we examine the impact of MAF1b expression during chronic T. gondii infection. We find that mice infected with MAF1b-expressing parasites have higher cyst burden and cytokine levels than their wild-type counterparts. A better understanding of the genes involved in establishing and maintaining chronic infection will aid in discovering effective therapeutics for chronically infected individuals.
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Abstract
Chemogenetic technologies enable selective pharmacological control of specific cell populations. An increasing number of approaches have been developed that modulate different signaling pathways. Selective pharmacological control over G protein-coupled receptor signaling, ion channel conductances, protein association, protein stability, and small molecule targeting allows modulation of cellular processes in distinct cell types. Here, we review these chemogenetic technologies and instances of their applications in complex tissues in vivo and ex vivo.
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Affiliation(s)
- Deniz Atasoy
- Department of Physiology, School of Medicine and Regenerative-Restorative Medicine Research Center (REMER), Istanbul Medipol University , Istanbul , Turkey ; and Janelia Research Campus, Howard Hughes Medical Institute , Ashburn, Virginia
| | - Scott M Sternson
- Department of Physiology, School of Medicine and Regenerative-Restorative Medicine Research Center (REMER), Istanbul Medipol University , Istanbul , Turkey ; and Janelia Research Campus, Howard Hughes Medical Institute , Ashburn, Virginia
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Morlon-Guyot J, El Hajj H, Martin K, Fois A, Carrillo A, Berry L, Burchmore R, Meissner M, Lebrun M, Daher W. A proteomic analysis unravels novel CORVET and HOPS proteins involved in Toxoplasma gondii
secretory organelles biogenesis. Cell Microbiol 2018; 20:e12870. [DOI: 10.1111/cmi.12870] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 05/23/2018] [Accepted: 06/05/2018] [Indexed: 01/10/2023]
Affiliation(s)
- Juliette Morlon-Guyot
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM; Université de Montpellier; Montpellier France
| | - Hiba El Hajj
- Departments of Internal Medicine and Experimental Pathology, Immunology and Microbiology; American University of Beirut; Beirut Lebanon
| | - Kevin Martin
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM; Université de Montpellier; Montpellier France
| | - Adrien Fois
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM; Université de Montpellier; Montpellier France
| | - Amandine Carrillo
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM; Université de Montpellier; Montpellier France
| | - Laurence Berry
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM; Université de Montpellier; Montpellier France
| | | | - Markus Meissner
- Wellcome Centre for Molecular Parasitology; University of Glasgow; Glasgow UK
- Department of Veterinary Sciences, Experimental Parasitology; Ludwig-Maximilians-Universität München; Munich Germany
| | - Maryse Lebrun
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM; Université de Montpellier; Montpellier France
| | - Wassim Daher
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM; Université de Montpellier; Montpellier France
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Natsume T, Kanemaki MT. Conditional Degrons for Controlling Protein Expression at the Protein Level. Annu Rev Genet 2018; 51:83-102. [PMID: 29178817 DOI: 10.1146/annurev-genet-120116-024656] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The conditional depletion of a protein of interest (POI) is useful not only for loss-of-function studies, but also for the modulation of biological pathways. Technologies that work at the level of DNA, mRNA, and protein are available for temporal protein depletion. Compared with technologies targeting the pretranslation steps, direct protein depletion (or protein knockdown approaches) is advantageous in terms of specificity, reversibility, and time required for depletion, which can be achieved by fusing a POI with a protein domain called a degron that induces rapid proteolysis of the fusion protein. Conditional degrons can be activated or inhibited by temperature, small molecules, light, or the expression of another protein. The conditional degron-based technologies currently available are described and discussed.
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Affiliation(s)
- Toyoaki Natsume
- Division of Molecular Cell Engineering, National Institute of Genetics, Research Organization of Information and Systems (ROIS), and Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka 411-8540, Japan;
| | - Masato T Kanemaki
- Division of Molecular Cell Engineering, National Institute of Genetics, Research Organization of Information and Systems (ROIS), and Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka 411-8540, Japan;
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Morlon-Guyot J, Berry L, Sauquet I, Singh Pall G, El Hajj H, Meissner M, Daher W. Conditional knock-down of a novel coccidian protein leads to the formation of aberrant apical organelles and abrogates mature rhoptry positioning in Toxoplasma gondii. Mol Biochem Parasitol 2018; 223:19-30. [DOI: 10.1016/j.molbiopara.2018.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/23/2018] [Accepted: 06/23/2018] [Indexed: 01/21/2023]
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Kogenaru M, Isalan M. Drug-Inducible Control of Lethality Genes: A Low Background Destabilizing Domain Architecture Applied to the Gal4-UAS System in Drosophila. ACS Synth Biol 2018; 7:1496-1506. [PMID: 29733646 PMCID: PMC6008732 DOI: 10.1021/acssynbio.7b00302] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Indexed: 11/28/2022]
Abstract
Destabilizing domains (DDs) are genetic tags that conditionally control the level of abundance of proteins-of-interest (POI) with specific stabilizing small-molecule drugs, rapidly and reversibly, in a wide variety of organisms. The amount of the DD-tagged fusion protein directly impacts its molecular function. Hence, it is important that the background levels be tightly regulated in the absence of any drug. This is especially true for classes of proteins that function at extremely low levels, such as lethality genes involved in tissue development and certain transcriptional activator proteins. Here, we establish the uninduced background and induction levels for two widely used DDs (FKBP and DHFR) by developing an accurate quantification method. We show that both DDs exhibit functional background levels in the absence of a drug, but each to a different degree. To overcome this limitation, we systematically test a double architecture for these DDs (DD-POI-DD) that completely suppresses the protein's function in an uninduced state, while allowing tunable functional levels upon adding a drug. As an example, we generate a drug-stabilizable Gal4 transcriptional activator with extremely low background levels. We show that this functions in vivo in the widely used Gal4-UAS bipartite expression system in Drosophila melanogaster. By regulating a cell death gene, we demonstrate that only the low background double architecture enables tight regulation of the lethal phenotype in vivo. These improved tools will enable applications requiring exceptionally tight control of protein function in living cells and organisms.
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Affiliation(s)
| | - Mark Isalan
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom
- Imperial College Centre
for
Synthetic Biology, Imperial College London, London, SW7 2AZ, United Kingdom
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36
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Abstract
A synthesis of the important FKBP ligand Shld is reported. The synthesis avoids stoichiometric use of expensive and chiral reagents, maintains enantioselectivity and provides a high overall yield (39%). The main features in the method are enantioselective alkylation for preparation of the phenyl acetic acid moiety (building block A), catalytic enantioselective reduction for obtaining the chiral diaryl-1-propanol (building block C), and direct acylation of S-pipecolic tartrate rather than use of expensive Fmoc-pipecolic acid. The assembly of the building blocks A-C is reversed in comparison to previous synthesis, which also eliminates the need for protective groups.
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Affiliation(s)
| | - Mikael Bols
- Department of Chemistry , University of Copenhagen , Universitetsparken 5 , 2100 Copenhagen Ø , Denmark
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37
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Radke JB, Worth D, Hong D, Huang S, Sullivan WJ, Wilson EH, White MW. Transcriptional repression by ApiAP2 factors is central to chronic toxoplasmosis. PLoS Pathog 2018; 14:e1007035. [PMID: 29718996 PMCID: PMC5951591 DOI: 10.1371/journal.ppat.1007035] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 05/14/2018] [Accepted: 04/17/2018] [Indexed: 12/20/2022] Open
Abstract
Tachyzoite to bradyzoite development in Toxoplasma is marked by major changes in gene expression resulting in a parasite that expresses a new repertoire of surface antigens hidden inside a modified parasitophorous vacuole called the tissue cyst. The factors that control this important life cycle transition are not well understood. Here we describe an important transcriptional repressor mechanism controlling bradyzoite differentiation that operates in the tachyzoite stage. The ApiAP2 factor, AP2IV-4, is a nuclear factor dynamically expressed in late S phase through mitosis/cytokinesis of the tachyzoite cell cycle. Remarkably, deletion of the AP2IV-4 locus resulted in the expression of a subset of bradyzoite-specific proteins in replicating tachyzoites that included tissue cyst wall components BPK1, MCP4, CST1 and the surface antigen SRS9. In the murine animal model, the mis-timing of bradyzoite antigens in tachyzoites lacking AP2IV-4 caused a potent inflammatory monocyte immune response that effectively eliminated this parasite and prevented tissue cyst formation in mouse brain tissue. Altogether, these results indicate that suppression of bradyzoite antigens by AP2IV-4 during acute infection is required for Toxoplasma to successfully establish a chronic infection in the immune-competent host. The Toxoplasma biology that underlies the establishment of a chronic infection is developmental conversion of the acute tachyzoite stage into the latent bradyzoite-tissue cyst stage. Despite the important clinical consequences of this developmental pathway, the molecular basis of the switch mechanisms that control formation of the tissue cyst is still poorly understood. A fundamental feature of tissue cyst formation is the expression of bradyzoite-specific genes. Here we show the transcription factor AP2IV-4 directly silences bradyzoite mRNA and protein expression in the acute tachyzoite stage demonstrating that developmental control of tissue cyst formation is as much about when not to express bradyzoite genes as it is about when to activate them. Losing the suppression of bradyzoite gene expression in the acute tachyzoite stage caused by deleting AP2IV-4 blocked the establishment of chronic disease in healthy animals via increased protective immunity suggesting a possible strategy for preventing chronic Toxoplasma infections.
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Affiliation(s)
- Joshua B. Radke
- Department of Global Health, University of South Florida, Tampa, FL, United States of America
| | - Danielle Worth
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, United States of America
| | - David Hong
- Department of Global Health, University of South Florida, Tampa, FL, United States of America
| | - Sherri Huang
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States of America
| | - William J. Sullivan
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States of America
| | - Emma H. Wilson
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, United States of America
| | - Michael W. White
- Department of Global Health, University of South Florida, Tampa, FL, United States of America
- * E-mail:
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Zhang J, Yin K, Sun J, Gao J, Du Q, Li H, Qiu J. Direct and tunable modulation of protein levels in rice and wheat with a synthetic small molecule. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:472-481. [PMID: 28682500 PMCID: PMC5787845 DOI: 10.1111/pbi.12787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 06/24/2017] [Accepted: 07/03/2017] [Indexed: 06/07/2023]
Abstract
Direct control of protein level enables rapid and efficient analyses of gene functions in crops. Previously, we developed the RDDK-Shield1 (Shld1) system in the model plant Arabidopsis thaliana for direct modulation of protein stabilization using a synthetic small molecule. However, it was unclear whether this system is applicable to economically important crops. In this study, we show that the RDDK-Shld1 system enables rapid and tunable control of protein levels in rice and wheat. Accumulation of RDDK fusion proteins can be reversibly and spatio-temporally controlled by the synthetic small-molecule Shld1. Moreover, RDDK-Bar and RDDK-Pid3 fusions confer herbicide and rice blast resistance, respectively, in a Shld1-dependent manner. Therefore, the RDDK-Shld1 system provides a reversible and tunable technique for controlling protein functions and conditional expression of transgenes in crops.
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Affiliation(s)
- Jingbo Zhang
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Kangquan Yin
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
| | - Juan Sun
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
| | - Jinlan Gao
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
| | - Qiuli Du
- Department of Life Science and EngineeringJining UniversityQufuChina
- National Center for Soybean ImprovementNational Key Laboratory of Crop Genetics and Germplasm EnhancementNanjing Agricultural UniversityNanjingChina
| | - Huali Li
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
| | - Jin‐Long Qiu
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
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Jia Y, Marq JB, Bisio H, Jacot D, Mueller C, Yu L, Choudhary J, Brochet M, Soldati-Favre D. Crosstalk between PKA and PKG controls pH-dependent host cell egress of Toxoplasma gondii. EMBO J 2017; 36:3250-3267. [PMID: 29030485 PMCID: PMC5666616 DOI: 10.15252/embj.201796794] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 09/08/2017] [Accepted: 09/12/2017] [Indexed: 12/27/2022] Open
Abstract
Toxoplasma gondii encodes three protein kinase A catalytic (PKAc1-3) and one regulatory (PKAr) subunits to integrate cAMP-dependent signals. Here, we show that inactive PKAc1 is maintained at the parasite pellicle by interacting with acylated PKAr. Either a conditional knockdown of PKAr or the overexpression of PKAc1 blocks parasite division. Conversely, down-regulation of PKAc1 or stabilisation of a dominant-negative PKAr isoform that does not bind cAMP triggers premature parasite egress from infected cells followed by serial invasion attempts leading to host cell lysis. This untimely egress depends on host cell acidification. A phosphoproteome analysis suggested the interplay between cAMP and cGMP signalling as PKAc1 inactivation changes the phosphorylation profile of a putative cGMP-phosphodiesterase. Concordantly, inhibition of the cGMP-dependent protein kinase G (PKG) blocks egress induced by PKAc1 inactivation or environmental acidification, while a cGMP-phosphodiesterase inhibitor circumvents egress repression by PKAc1 or pH neutralisation. This indicates that pH and PKAc1 act as balancing regulators of cGMP metabolism to control egress. These results reveal a crosstalk between PKA and PKG pathways to govern egress in T. gondii.
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Affiliation(s)
- Yonggen Jia
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva 4, Switzerland
| | - Jean-Baptiste Marq
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva 4, Switzerland
| | - Hugo Bisio
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva 4, Switzerland
| | - Damien Jacot
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva 4, Switzerland
| | - Christina Mueller
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva 4, Switzerland
| | - Lu Yu
- Proteomic Mass-spectrometry Team, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Jyoti Choudhary
- Proteomic Mass-spectrometry Team, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Mathieu Brochet
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva 4, Switzerland
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva 4, Switzerland
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40
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Bonner JM, Boulianne GL. Diverse structures, functions and uses of FK506 binding proteins. Cell Signal 2017; 38:97-105. [DOI: 10.1016/j.cellsig.2017.06.013] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 06/15/2017] [Accepted: 06/20/2017] [Indexed: 02/08/2023]
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Affiliation(s)
- George M. Burslem
- Departments of Molecular,
Cellular, and Developmental Biology, Chemistry, and Pharmacology, Yale University, 219 Prospect Street, New Haven, Connecticut 06511, United States
| | - Craig M. Crews
- Departments of Molecular,
Cellular, and Developmental Biology, Chemistry, and Pharmacology, Yale University, 219 Prospect Street, New Haven, Connecticut 06511, United States
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42
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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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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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Venugopal K, Werkmeister E, Barois N, Saliou JM, Poncet A, Huot L, Sindikubwabo F, Hakimi MA, Langsley G, Lafont F, Marion S. Dual role of the Toxoplasma gondii clathrin adaptor AP1 in the sorting of rhoptry and microneme proteins and in parasite division. PLoS Pathog 2017; 13:e1006331. [PMID: 28430827 PMCID: PMC5415223 DOI: 10.1371/journal.ppat.1006331] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 05/03/2017] [Accepted: 04/03/2017] [Indexed: 12/13/2022] Open
Abstract
Toxoplasma gondii possesses a highly polarized secretory system, which efficiently assembles de novo micronemes and rhoptries during parasite replication. These apical secretory organelles release their contents into host cells promoting parasite invasion and survival. Using a CreLox-based inducible knock-out strategy and the ddFKBP over-expression system, we unraveled novel functions of the clathrin adaptor complex TgAP1. First, our data indicate that AP1 in T. gondii likely functions as a conserved heterotetrameric complex composed of the four subunits γ, β, μ1, σ1 and interacts with known regulators of clathrin-mediated vesicular budding such as the unique ENTH-domain containing protein, which we named Epsin-like protein (TgEpsL). Disruption of the μ1 subunit resulted in the mis-sorting of microneme proteins at the level of the Trans-Golgi-Network (TGN). Furthermore, we demonstrated that TgAP1 regulates rhoptry biogenesis by activating rhoptry protein exit from the TGN, but also participates in the post-Golgi maturation process of preROP compartments into apically anchored club-shaped mature organelles. For this latter activity, our data indicate a specific functional relationship between TgAP1 and the Rab5A-positive endosome-like compartment. In addition, we unraveled an original role for TgAP1 in the regulation of parasite division. APμ1-depleted parasites undergo normal daughter cell budding and basal complex assembly but fail to segregate at the end of cytokinesis. The phylum Apicomplexa comprises a large group of obligate intracellular parasites of wide human and agricultural significance. Most notable are Plasmodium, the causative agent of malaria, and Toxoplasma gondii, one of the most common human parasites, responsible for disease of the developing fetus and immune-compromised individuals. Apicomplexa are characterized by the presence of an apical complex consisting of secretory organelles named micronemes (MIC) and rhoptries (ROP). MIC and ROP proteins, released upon host cell recognition, are essential for host cell invasion and parasite survival. After invasion, these organelles are neo-synthesized at each parasite replication cycle. In our study, we demonstrate a crucial role for the T. gondii clathrin adaptor complex AP1 in the vesicular transport of neo-synthesized MIC and ROP proteins, thereby regulating mature apical organelle formation. In addition, we unravel an original role for TgAP1 in the late stages of the parasite division process during daughter cell segregation. Therefore, our study provides new insights into key regulatory mechanisms of the vesicular trafficking system essential for host invasion and intracellular survival of Toxoplasma gondii.
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Affiliation(s)
- Kannan Venugopal
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Elisabeth Werkmeister
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Nicolas Barois
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Jean-Michel Saliou
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Anais Poncet
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Ludovic Huot
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Fabien Sindikubwabo
- IAB, Team Host-pathogen interactions & immunity to infection, Université Grenoble Alpes, Inserm U1209, CNRS UMR5309, Grenoble, France
| | - Mohamed Ali Hakimi
- IAB, Team Host-pathogen interactions & immunity to infection, Université Grenoble Alpes, Inserm U1209, CNRS UMR5309, Grenoble, France
| | - Gordon Langsley
- Laboratoire de Biologie Cellulaire Comparative des Apicomplexes, Faculté de Médicine, Université Paris Descartes-Sorbonne Paris Cité, France. Inserm U1016, CNRS UMR8104, Institut Cochin, Paris, France
| | - Frank Lafont
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Sabrina Marion
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
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45
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Periz J, Whitelaw J, Harding C, Gras S, Del Rosario Minina MI, Latorre-Barragan F, Lemgruber L, Reimer MA, Insall R, Heaslip A, Meissner M. Toxoplasma gondii F-actin forms an extensive filamentous network required for material exchange and parasite maturation. eLife 2017; 6:e24119. [PMID: 28322189 PMCID: PMC5375643 DOI: 10.7554/elife.24119] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 03/09/2017] [Indexed: 01/14/2023] Open
Abstract
Apicomplexan actin is important during the parasite's life cycle. Its polymerization kinetics are unusual, permitting only short, unstable F-actin filaments. It has not been possible to study actin in vivo and so its physiological roles have remained obscure, leading to models distinct from conventional actin behaviour. Here a modified version of the commercially available actin-chromobody was tested as a novel tool for visualising F-actin dynamics in Toxoplasma gondii. Cb labels filamentous actin structures within the parasite cytosol and labels an extensive F-actin network that connects parasites within the parasitophorous vacuole and allows vesicles to be exchanged between parasites. In the absence of actin, parasites lack a residual body and inter-parasite connections and grow in an asynchronous and disorganized manner. Collectively, these data identify new roles for actin in the intracellular phase of the parasites lytic cycle and provide a robust new tool for imaging parasitic F-actin dynamics.
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Affiliation(s)
- Javier Periz
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Jamie Whitelaw
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Clare Harding
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Simon Gras
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Mario Igor Del Rosario Minina
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Fernanda Latorre-Barragan
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Leandro Lemgruber
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Madita Alice Reimer
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Robert Insall
- Cancer Research United Kingdom Beatson Institute, Bearsden, United Kingdom
| | - Aoife Heaslip
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, United States
| | - Markus Meissner
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
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Opposing Transcriptional Mechanisms Regulate Toxoplasma Development. mSphere 2017; 2:mSphere00347-16. [PMID: 28251183 PMCID: PMC5322347 DOI: 10.1128/msphere.00347-16] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 02/01/2017] [Indexed: 11/20/2022] Open
Abstract
Toxoplasma infections are lifelong because of the development of the bradyzoite tissue cyst, which is effectively invisible to the immune system. Despite the important clinical consequences of this developmental pathway, the molecular basis of the switch mechanisms that control tissue cyst formation is still poorly understood. Significant changes in gene expression are associated with tissue cyst development, and ApiAP2 transcription factors are an important mechanism regulating this developmental transcriptome. However, the molecular composition of these ApiAP2 complexes and the operating principles of ApiAP2 mechanisms are not well defined. Here we establish that competing ApiAP2 transcriptional mechanisms operate to regulate this clinically important developmental pathway. The Toxoplasma biology that underlies human chronic infection is developmental conversion of the acute tachyzoite stage into the latent bradyzoite stage. We investigated the roles of two alkaline-stress-induced ApiAP2 transcription factors, AP2IV-3 and AP2IX-9, in bradyzoite development. These factors were expressed in two overlapping waves during bradyzoite development, with AP2IX-9 increasing expression earlier than AP2IV-3, which peaked as AP2IX-9 expression was declining. Disruption of the AP2IX-9 gene enhanced, while deletion of AP2IV-3 gene decreased, tissue cyst formation, demonstrating that these factors have opposite functions in bradyzoite development. Conversely, conditional overexpression of FKBP-modified AP2IX-9 or AP2IV-3 with the small molecule Shield 1 had a reciprocal effect on tissue cyst formation, confirming the conclusions of the knockout experiments. The AP2IX-9 repressor and AP2IV-3 activator tissue cyst phenotypes were borne out in gene expression studies that determined that many of the same bradyzoite genes were regulated in an opposite manner by these transcription factors. A common gene target was the canonical bradyzoite marker BAG1, and mechanistic experiments determined that, like AP2IX-9, AP2IV-3 regulates a BAG1 promoter-luciferase reporter and specifically binds the BAG1 promoter in parasite chromatin. Altogether, these results suggest that the AP2IX-9 transcriptional repressor and the AP2IV-3 transcriptional activator likely compete to control bradyzoite gene expression, which may permit Toxoplasma to better adapt to different tissue environments and select a suitable host cell for long-term survival of the dormant tissue cyst. IMPORTANCEToxoplasma infections are lifelong because of the development of the bradyzoite tissue cyst, which is effectively invisible to the immune system. Despite the important clinical consequences of this developmental pathway, the molecular basis of the switch mechanisms that control tissue cyst formation is still poorly understood. Significant changes in gene expression are associated with tissue cyst development, and ApiAP2 transcription factors are an important mechanism regulating this developmental transcriptome. However, the molecular composition of these ApiAP2 complexes and the operating principles of ApiAP2 mechanisms are not well defined. Here we establish that competing ApiAP2 transcriptional mechanisms operate to regulate this clinically important developmental pathway.
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Whitelaw JA, Latorre-Barragan F, Gras S, Pall GS, Leung JM, Heaslip A, Egarter S, Andenmatten N, Nelson SR, Warshaw DM, Ward GE, Meissner M. Surface attachment, promoted by the actomyosin system of Toxoplasma gondii is important for efficient gliding motility and invasion. BMC Biol 2017; 15:1. [PMID: 28100223 PMCID: PMC5242020 DOI: 10.1186/s12915-016-0343-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 12/10/2016] [Indexed: 12/17/2022] Open
Abstract
Background Apicomplexan parasites employ a unique form of movement, termed gliding motility, in order to invade the host cell. This movement depends on the parasite’s actomyosin system, which is thought to generate the force during gliding. However, recent evidence questions the exact molecular role of this system, since mutants for core components of the gliding machinery, such as parasite actin or subunits of the MyoA-motor complex (the glideosome), remain motile and invasive, albeit at significantly reduced efficiencies. While compensatory mechanisms and unusual polymerisation kinetics of parasite actin have been evoked to explain these findings, the actomyosin system could also play a role distinct from force production during parasite movement. Results In this study, we compared the phenotypes of different mutants for core components of the actomyosin system in Toxoplasma gondii to decipher their exact role during gliding motility and invasion. We found that, while some phenotypes (apicoplast segregation, host cell egress, dense granule motility) appeared early after induction of the act1 knockout and went to completion, a small percentage of the parasites remained capable of motility and invasion well past the point at which actin levels were undetectable. Those act1 conditional knockout (cKO) and mlc1 cKO that continue to move in 3D do so at speeds similar to wildtype parasites. However, these mutants are virtually unable to attach to a collagen-coated substrate under flow conditions, indicating an important role for the actomyosin system of T. gondii in the formation of attachment sites. Conclusion We demonstrate that parasite actin is essential during the lytic cycle and cannot be compensated by other molecules. Our data suggest a conventional polymerisation mechanism in vivo that depends on a critical concentration of G-actin. Importantly, we demonstrate that the actomyosin system of the parasite functions in attachment to the surface substrate, and not necessarily as force generator. Electronic supplementary material The online version of this article (doi:10.1186/s12915-016-0343-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jamie A Whitelaw
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow, G12 8TA, UK
| | - Fernanda Latorre-Barragan
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow, G12 8TA, UK
| | - Simon Gras
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow, G12 8TA, UK
| | - Gurman S Pall
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow, G12 8TA, UK
| | - Jacqueline M Leung
- Department of Biology, Indiana University, Bloomington, Myers Hall 240, 915 E 3rd St Bloomington, Bloomington, IN, 47405, USA.,University of Vermont, Department of Microbiology and Molecular Genetics, College of Medicine, Burlington, VT, 05405, USA
| | - Aoife Heaslip
- University of Vermont, Department of Molecular Physiology and Biophysics Burlington, Vermont, 05405, USA
| | - Saskia Egarter
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow, G12 8TA, UK
| | - Nicole Andenmatten
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow, G12 8TA, UK
| | - Shane R Nelson
- University of Vermont, Department of Molecular Physiology and Biophysics Burlington, Vermont, 05405, USA
| | - David M Warshaw
- University of Vermont, Department of Molecular Physiology and Biophysics Burlington, Vermont, 05405, USA
| | - Gary E Ward
- University of Vermont, Department of Microbiology and Molecular Genetics, College of Medicine, Burlington, VT, 05405, USA
| | - Markus Meissner
- Wellcome Trust Centre For Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow, G12 8TA, UK.
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Phosphatidic Acid-Mediated Signaling Regulates Microneme Secretion in Toxoplasma. Cell Host Microbe 2016; 19:349-60. [PMID: 26962945 DOI: 10.1016/j.chom.2016.02.006] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 09/28/2015] [Accepted: 02/17/2016] [Indexed: 11/24/2022]
Abstract
The obligate intracellular lifestyle of apicomplexan parasites necessitates an invasive phase underpinned by timely and spatially controlled secretion of apical organelles termed micronemes. In Toxoplasma gondii, extracellular potassium levels and other stimuli trigger a signaling cascade culminating in phosphoinositide-phospholipase C (PLC) activation, which generates the second messengers diacylglycerol (DAG) and IP3 and ultimately results in microneme secretion. Here we show that a delicate balance between DAG and its downstream product, phosphatidic acid (PA), is essential for controlling microneme release. Governing this balance is the apicomplexan-specific DAG-kinase-1, which interconverts PA and DAG, and whose depletion impairs egress and causes parasite death. Additionally, we identify an acylated pleckstrin-homology (PH) domain-containing protein (APH) on the microneme surface that senses PA during microneme secretion and is necessary for microneme exocytosis. As APH is conserved in Apicomplexa, these findings highlight a potentially widely used mechanism in which key lipid mediators regulate microneme exocytosis.
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Serpeloni M, Jiménez-Ruiz E, Vidal NM, Kroeber C, Andenmatten N, Lemgruber L, Mörking P, Pall GS, Meissner M, Ávila AR. UAP56 is a conserved crucial component of a divergent mRNA export pathway in Toxoplasma gondii. Mol Microbiol 2016; 102:672-689. [PMID: 27542978 PMCID: PMC5118106 DOI: 10.1111/mmi.13485] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/18/2016] [Indexed: 01/28/2023]
Abstract
Nucleo‐cytoplasmic RNA export is an essential post‐transcriptional step to control gene expression in eukaryotic cells and is poorly understood in apicomplexan parasites. With the exception of UAP56, a component of TREX (Transcription Export) complex, other components of mRNA export machinery are not well conserved in divergent supergroups. Here, we use Toxoplasma gondii as a model system to functionally characterize TgUAP56 and its potential interaction factors. We demonstrate that TgUAP56 is crucial for mRNA export and that functional interference leads to significant accumulation of mRNA in the nucleus. It was necessary to employ bioinformatics and phylogenetic analysis to identify orthologs related to mRNA export, which show a remarkable low level of conservation in T. gondii. We adapted a conditional Cas9/CRISPR system to carry out a genetic screen to verify if these factors were involved in mRNA export in T. gondii. Only the disruption of TgRRM_1330 caused accumulation of mRNA in the nucleus as found with TgUAP56. This protein is potentially a divergent partner of TgUAP56, and provides insight into a divergent mRNA export pathway in apicomplexans.
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Affiliation(s)
- Mariana Serpeloni
- Instituto Carlos Chagas, FIOCRUZ, Curitiba, Brazil.,Departamento de Biologia Celular e Molecular, Universidade Federal do Paraná, Curitiba, Brazil.,College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity & Inflammation, Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, UK
| | - Elena Jiménez-Ruiz
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity & Inflammation, Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, UK
| | - Newton Medeiros Vidal
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Constanze Kroeber
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity & Inflammation, Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, UK
| | - Nicole Andenmatten
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity & Inflammation, Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, UK
| | - Leandro Lemgruber
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity & Inflammation, Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, UK
| | | | - Gurman S Pall
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity & Inflammation, Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, UK
| | - Markus Meissner
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity & Inflammation, Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, UK
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Morse D, Webster W, Kalanon M, Langsley G, McFadden GI. Plasmodium falciparum Rab1A Localizes to Rhoptries in Schizonts. PLoS One 2016; 11:e0158174. [PMID: 27348424 PMCID: PMC4922565 DOI: 10.1371/journal.pone.0158174] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 06/11/2016] [Indexed: 12/17/2022] Open
Abstract
Over-expression of a GFP-PfRab1A fusion protein in Plasmodium falciparum schizonts produces a punctate pattern of fluorescence typical of rhoptries, secretory organelles involved in host cell invasion. The GFP-positive bodies were purified by a combination of differential and density gradient centrifugation and their protein content determined by MS/MS sequencing. Consistent with the GFP rhoptry-like pattern of transgenic parasites, four of the 19 proteins identified have been previously described to be rhoptry-associated and another four are ER or ER-associated proteins. Confirmation that GFP-PfRab1A decorates rhoptries was obtained by its co-localization with Rap1 and Ron4 in late phase schizonts. We conclude that PfRab1A potentially regulates vesicular traffic from the endoplasmic reticulum to the rhoptries in Apicomplexa parasites.
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Affiliation(s)
- David Morse
- School of BioSciences, University of Melbourne, Melbourne, VIC, 3010, Australia
- * E-mail:
| | - Wesley Webster
- School of BioSciences, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Ming Kalanon
- School of BioSciences, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Gordon Langsley
- Laboratoire de Biologie Cellulaire Comparative des Apicomplexes, Institut Cochin, INSERM U1016, CNRS UMR 8104, Université Paris Descartes, 75014, Paris, France
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