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Sun SY, Segev-Zarko LA, Pintilie GD, Kim CY, Staggers SR, Schmid MF, Egan ES, Chiu W, Boothroyd JC. Cryogenic electron tomography reveals novel structures in the apical complex of Plasmodium falciparum. mBio 2024; 15:e0286423. [PMID: 38456679 PMCID: PMC11005440 DOI: 10.1128/mbio.02864-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 02/07/2024] [Indexed: 03/09/2024] Open
Abstract
Intracellular infectious agents, like the malaria parasite, Plasmodium falciparum, face the daunting challenge of how to invade a host cell. This problem may be even harder when the host cell in question is the enucleated red blood cell, which lacks the host machinery co-opted by many pathogens for internalization. Evolution has provided P. falciparum and related single-celled parasites within the phylum Apicomplexa with a collection of organelles at their apical end that mediate invasion. This apical complex includes at least two sets of secretory organelles, micronemes and rhoptries, and several structural features like apical rings and a putative pore through which proteins may be introduced into the host cell during invasion. We perform cryogenic electron tomography (cryo-ET) equipped with Volta Phase Plate on isolated and vitrified merozoites to visualize the apical machinery. Through tomographic reconstruction of cellular compartments, we see new details of known structures like the rhoptry tip interacting directly with a rosette resembling the recently described rhoptry secretory apparatus (RSA), or with an apical vesicle docked beneath the RSA. Subtomogram averaging reveals that the apical rings have a fixed number of repeating units, each of which is similar in overall size and shape to the units in the apical rings of tachyzoites of Toxoplasma gondii. Comparison of these polar rings in Plasmodium and Toxoplasma parasites also reveals them to have a structurally conserved assembly pattern. These results provide new insight into the essential and structurally conserved features of this remarkable machinery used by apicomplexan parasites to invade their respective host cells. IMPORTANCE Malaria is an infectious disease caused by parasites of the genus Plasmodium and is a leading cause of morbidity and mortality globally. Upon infection, Plasmodium parasites invade and replicate in red blood cells, where they are largely protected from the immune system. To enter host cells, the parasites employ a specialized apparatus at their anterior end. In this study, advanced imaging techniques like cryogenic electron tomography (cryo-ET) and Volta Phase Plate enable unprecedented visualization of whole Plasmodium falciparum merozoites, revealing previously unknown structural details of their invasion machinery. Key findings include new insights into the structural conservation of apical rings shared between Plasmodium and its apicomplexan cousin, Toxoplasma. These discoveries shed light on the essential and conserved elements of the invasion machinery used by these pathogens. Moreover, the research provides a foundation for understanding the molecular mechanisms underlying parasite-host interactions, potentially informing strategies for combating diseases caused by apicomplexan parasites.
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Affiliation(s)
- Stella Y. Sun
- Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Bioengineering, James H. Clark Center, Stanford University, Stanford, California, USA
| | - Li-av Segev-Zarko
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Grigore D. Pintilie
- Department of Bioengineering, James H. Clark Center, Stanford University, Stanford, California, USA
| | - Chi Yong Kim
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA
| | - Sophia R. Staggers
- Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Michael F. Schmid
- Division of Cryo-EM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California, USA
| | - Elizabeth S. Egan
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA
| | - Wah Chiu
- Department of Bioengineering, James H. Clark Center, Stanford University, Stanford, California, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
- Division of Cryo-EM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California, USA
| | - John C. Boothroyd
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
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2
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Micchelli CE, Percopo C, Traver M, Brzostowski J, Amin SN, Prigge ST, Sá JM, Wellems TE. Progressive heterogeneity of enlarged and irregularly shaped apicoplasts in P. falciparum persister blood stages after drug treatment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.03.574077. [PMID: 38410435 PMCID: PMC10896342 DOI: 10.1101/2024.01.03.574077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Morphological modifications and shifts in organelle relationships are hallmarks of dormancy in eukaryotic cells. Communications between altered mitochondria and nuclei are associated with metabolic quiescence of cancer cells that can survive chemotherapy. In plants, changes in the pathways between nuclei, mitochondria, and chloroplasts are associated with cold stress and bud dormancy. Plasmodium falciparum parasites, the deadliest agent of malaria in humans, contain a chloroplast-like organelle (apicoplast) derived from an ancient photosynthetic symbiont. Antimalarial treatments can fail because a small fraction of the blood stage parasites enter dormancy and recrudesce after drug exposure. Altered mitochondrial-nuclear interactions in these persisters have been described for P. falciparum, but interactions of the apicoplast remained to be characterized. In the present study, we examined the apicoplasts of dormant persisters obtained after exposure to dihydroartemisinin (a first-line antimalarial drug) followed by sorbitol treatment, or after exposure to sorbitol treatment alone. As previously observed, the mitochondrion of persisters was consistently enlarged and in close association with the nucleus. In contrast, the apicoplast varied from compact and oblate, like those of active ring stage parasites, to enlarged and irregularly shaped. Enlarged apicoplasts became more prevalent later in dormancy, but regular size apicoplasts subsequently predominated when actively replicating parasites recrudesced. All three organelles, nucleus, mitochondrion, and apicoplast, became closer during dormancy. Understanding their relationships in erythrocytic-stage persisters may lead to new strategies to prevent recrudescences and protect the future of malaria chemotherapy.
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Affiliation(s)
- Chiara E. Micchelli
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Caroline Percopo
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Maria Traver
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Joseph Brzostowski
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Shuchi N. Amin
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Sean T. Prigge
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore Maryland, USA
| | - Juliana M. Sá
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Thomas E. Wellems
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
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3
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Anwar O, Islam M, Thakur V, Kaur I, Mohmmed A. Defining ER-mitochondria contact dynamics in Plasmodium falciparum by targeting component of phospholipid synthesis pathway, Phosphatidylserine synthase (PfPSS). Mitochondrion 2022; 65:124-138. [PMID: 35623558 DOI: 10.1016/j.mito.2022.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 05/14/2022] [Accepted: 05/22/2022] [Indexed: 10/18/2022]
Abstract
The malaria parasite completes the asexual cycle inside the host erythrocyte, which requires extensive membrane biogenesis for its development and multiplication. Metabolic pathways for the synthesis of membrane phospholipids (PL), including phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS), are crucial for parasite survival. Here, we have studied the P. falciparum enzyme responsible for PS synthesis, Phosphatidylserine synthase (PfPSS), GFP targeting approach confirmed it to be localized in the parasite ER as well as in ER-protrusions. Detailed high resolution microscopy, using these transgenic parasites expressing PfPSS-GFP, redefined the dynamics of ER during the intraerythrocytic life cycle and its association with the mitochondria. We report for the first time presence of ER-mitochondria contact (ERMC) in Plasmodium; ERMC is formed by PfPSS containing ER-protrusions, which associate with the mitochondria surface throughout the parasite growth cycle. Further, ERMC is found to be stable and refractory to ER and mitochondrial stresses, suggesting that it is formed through strong tethering complexes. PfPSS was found to interact with other major key enzyme involved in PL synthesis, choline/Etn-phosphotransferase (CEPT), which suggest that ER is the major site for PL biosynthesis. Overall, this study defines the morphological organisation of ERMC which mediates PL synthesis/transport in the Plasmodium.
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Affiliation(s)
- Omair Anwar
- International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India
| | - Muzahidul Islam
- International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India
| | - Vandana Thakur
- International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India
| | - Inderjeet Kaur
- International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India
| | - Asif Mohmmed
- International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India.
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4
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Elaagip A, Absalon S, Florentin A. Apicoplast Dynamics During Plasmodium Cell Cycle. Front Cell Infect Microbiol 2022; 12:864819. [PMID: 35573785 PMCID: PMC9100674 DOI: 10.3389/fcimb.2022.864819] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/11/2022] [Indexed: 11/21/2022] Open
Abstract
The deadly malaria parasite, Plasmodium falciparum, contains a unique subcellular organelle termed the apicoplast, which is a clinically-proven antimalarial drug target. The apicoplast is a plastid with essential metabolic functions that evolved via secondary endosymbiosis. As an ancient endosymbiont, the apicoplast retained its own genome and it must be inherited by daughter cells during cell division. During the asexual replication of P. falciparum inside human red blood cells, both the parasite, and the apicoplast inside it, undergo massive morphological changes, including DNA replication and division. The apicoplast is an integral part of the cell and thus its development is tightly synchronized with the cell cycle. At the same time, certain aspects of its dynamics are independent of nuclear division, representing a degree of autonomy in organelle biogenesis. Here, we review the different aspects of organelle dynamics during P. falciparum intraerythrocytic replication, summarize our current understanding of these processes, and describe the many open questions in this area of parasite basic cell biology.
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Affiliation(s)
- Arwa Elaagip
- Department of Parasitology and Medical Entomology, Faculty of Medical Laboratory Sciences, University of Khartoum, Khartoum, Sudan
| | - Sabrina Absalon
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States
- *Correspondence: Sabrina Absalon, ; Anat Florentin,
| | - Anat Florentin
- The Kuvin Center for the Study of Infectious and Tropical Diseases, Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
- *Correspondence: Sabrina Absalon, ; Anat Florentin,
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5
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Hammond M, Dorrell RG, Speijer D, Lukeš J. Eukaryotic cellular intricacies shape mitochondrial proteomic complexity. Bioessays 2022; 44:e2100258. [PMID: 35318703 DOI: 10.1002/bies.202100258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 03/08/2022] [Accepted: 03/09/2022] [Indexed: 12/17/2022]
Abstract
Mitochondria have been fundamental to the eco-physiological success of eukaryotes since the last eukaryotic common ancestor (LECA). They contribute essential functions to eukaryotic cells, above and beyond classical respiration. Mitochondria interact with, and complement, metabolic pathways occurring in other organelles, notably diversifying the chloroplast metabolism of photosynthetic organisms. Here, we integrate existing literature to investigate how mitochondrial metabolism varies across the landscape of eukaryotic evolution. We illustrate the mitochondrial remodelling and proteomic changes undergone in conjunction with major evolutionary transitions. We explore how the mitochondrial complexity of the LECA has been remodelled in specific groups to support subsequent evolutionary transitions, such as the acquisition of chloroplasts in photosynthetic species and the emergence of multicellularity. We highlight the versatile and crucial roles played by mitochondria during eukaryotic evolution, extending from its huge contribution to the development of the LECA itself to the dynamic evolution of individual eukaryote groups, reflecting both their current ecologies and evolutionary histories.
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Affiliation(s)
- Michael Hammond
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic.,Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Richard G Dorrell
- Institut de Biologie de l'ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Dave Speijer
- Medical Biochemistry, UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic.,Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
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6
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Abstract
Apicomplexan parasites, such as Toxoplasma gondii and Plasmodium falciparum, are the cause of many important human and animal diseases. While T. gondii tachyzoites replicate through endodyogeny, during which two daughter cells are formed within the parental cell, P. falciparum replicates through schizogony, where up to 32 parasites are formed in a single infected red blood cell and even thousands of daughter cells during mosquito- or liver-stage development. These processes require a tightly orchestrated division and distribution over the daughter parasites of one-per-cell organelles such as the mitochondrion and apicoplast. Although proper organelle segregation is highly essential, the molecular mechanism and the key proteins involved remain largely unknown. In this review, we describe organelle dynamics during cell division in T. gondii and P. falciparum, summarize the current understanding of the molecular mechanisms underlying organelle fission in these parasites, and introduce candidate fission proteins.
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7
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Abstract
The shape and number of mitochondria respond to the metabolic needs during the cell cycle of the eukaryotic cell. In the best-studied model systems of animals and fungi, the cells contain many mitochondria, each carrying its own nucleoid. The organelles, however, mostly exist as a dynamic network, which undergoes constant cycles of division and fusion. These mitochondrial dynamics are driven by intricate protein machineries centered around dynamin-related proteins (DRPs). Here, we review recent advances on the dynamics of mitochondria and mitochondrion-related organelles (MROs) of parasitic protists. In contrast to animals and fungi, many parasitic protists from groups of Apicomplexa or Kinetoplastida carry only a single mitochondrion with a single nucleoid. In these groups, mitochondrial division is strictly coupled to the cell cycle, and the morphology of the organelle responds to the cell differentiation during the parasite life cycle. On the other hand, anaerobic parasitic protists such as Giardia, Entamoeba, and Trichomonas contain multiple MROs that have lost their organellar genomes. We discuss the function of DRPs, the occurrence of mitochondrial fusion, and mitophagy in the parasitic protists from the perspective of eukaryote evolution.
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Affiliation(s)
- Luboš Voleman
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
| | - Pavel Doležal
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
- * E-mail:
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8
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Sharaf A, Füssy Z, Tomčala A, Richtová J, Oborník M. Isolation of plastids and mitochondria from Chromera velia. PLANTA 2019; 250:1731-1741. [PMID: 31422509 DOI: 10.1007/s00425-019-03259-3] [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: 06/19/2019] [Accepted: 08/08/2019] [Indexed: 06/10/2023]
Abstract
We present an easy and effective procedure to purify plastids and mitochondria from Chromera velia. Our method enables downstream analyses of protein and metabolite content of the organelles. Chromerids are alveolate algae that are the closest known phototrophic relatives to apicomplexan parasites such as Plasmodium or Toxoplasma. While genomic and transcriptomic resources for chromerids are in place, tools and experimental conditions for proteomic studies have not been developed yet. Here we describe a rapid and efficient protocol for simultaneous isolation of plastids and mitochondria from the chromerid alga Chromera velia. This procedure involves enzymatic treatment and breakage of cells, followed by differential centrifugation. While plastids sediment in the first centrifugation step, mitochondria remain in the supernatant. Subsequently, plastids can be purified from the crude pellet by centrifugation on a discontinuous 60%/70% sucrose density gradient, while mitochondria can be obtained by centrifugation on a discontinuous 33%/80% Percoll density gradient. Isolated plastids are autofluorescent, and their multi-membrane structure was confirmed by transmission electron microscopy. Fluorescent optical microscopy was used to identify isolated mitochondria stained with MitoTrackerTM green, while their intactness and membrane potential were confirmed by staining with MitoTrackerTM orange CMTMRos. Total proteins were extracted from isolated organellar fractions, and the purity of isolated organelles was confirmed using immunoblotting. Antibodies against the beta subunit of the mitochondrial ATP synthase and the plastid protochlorophyllide oxidoreductase did not cross-react on immunoblots, suggesting that each organellar fraction is free of the residues of the other. The presented protocol represents an essential step for further proteomic, organellar, and cell biological studies of C. velia and can be employed, with minor optimizations, in other thick-walled unicellular algae.
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Affiliation(s)
- Abdoallah Sharaf
- Institute of Parasitology, Biology Centre CAS, Branišovská 31, 37005, České Budějovice, Czech Republic.
- Genetic Department, Faculty of Agriculture, Ain Shams University, Cairo, 11241, Egypt.
| | - Zoltán Füssy
- Institute of Parasitology, Biology Centre CAS, Branišovská 31, 37005, České Budějovice, Czech Republic
| | - Aleš Tomčala
- Institute of Parasitology, Biology Centre CAS, Branišovská 31, 37005, České Budějovice, Czech Republic
| | - Jitka Richtová
- Institute of Parasitology, Biology Centre CAS, Branišovská 31, 37005, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská 31, 37005, České Budějovice, Czech Republic
| | - Miroslav Oborník
- Institute of Parasitology, Biology Centre CAS, Branišovská 31, 37005, České Budějovice, Czech Republic.
- Faculty of Science, University of South Bohemia, Branišovská 31, 37005, České Budějovice, Czech Republic.
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9
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Affiliation(s)
- Michael J. Boucher
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
| | - Ellen Yeh
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Pathology, Stanford University School of Medicine, Stanford, California, United States of America
- Chan Zuckerberg Biohub, San Francisco, California, United States of America
- * E-mail:
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10
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Method for the separation of mitochondria and apicoplast from the malaria parasite Plasmodium falciparum. Parasitol Int 2019; 69:99-102. [DOI: 10.1016/j.parint.2018.12.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Revised: 12/08/2018] [Accepted: 12/10/2018] [Indexed: 11/21/2022]
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11
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Ebrahimzadeh Z, Mukherjee A, Richard D. A map of the subcellular distribution of phosphoinositides in the erythrocytic cycle of the malaria parasite Plasmodium falciparum. Int J Parasitol 2017; 48:13-25. [PMID: 29154995 DOI: 10.1016/j.ijpara.2017.08.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 08/22/2017] [Accepted: 08/31/2017] [Indexed: 12/16/2022]
Abstract
Despite representing a small percentage of the cellular lipids of eukaryotic cells, phosphoinositides (PIPs) are critical in various processes such as intracellular trafficking and signal transduction. Central to their various functions is the differential distribution of PIP species to specific membrane compartments through the actions of kinases, phosphatases and lipases. Despite their importance in the malaria parasite lifecycle, the subcellular distribution of most PIP species in this organism is still unknown. We here localise several species of PIPs throughout the erythrocytic cycle of Plasmodium falciparum. We show that PI3P is mostly found at the apicoplast and the membrane of the food vacuole, that PI4P associates with the Golgi apparatus and the plasma membrane and that PI(4,5)P2, in addition to being detected at the plasma membrane, labels some cavity-like spherical structures. Finally, we show that the elusive PI5P localises to the plasma membrane, the nucleus and potentially to the transitional endoplasmic reticulum (ER). Our map of the subcellular distribution of PIP species in P. falciparum will be a useful tool to shed light on the dynamics of these lipids in this deadly parasite.
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Affiliation(s)
- Zeinab Ebrahimzadeh
- Centre de recherche en infectiologie, CRCHU de Québec-Université Laval, 2705 Boul. Laurier, Québec, QC G1V 4G2, Canada
| | - Angana Mukherjee
- Centre de recherche en infectiologie, CRCHU de Québec-Université Laval, 2705 Boul. Laurier, Québec, QC G1V 4G2, Canada
| | - Dave Richard
- Centre de recherche en infectiologie, CRCHU de Québec-Université Laval, 2705 Boul. Laurier, Québec, QC G1V 4G2, Canada.
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12
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Kraft LM, Lackner LL. Mitochondrial anchors: Positioning mitochondria and more. Biochem Biophys Res Commun 2017; 500:2-8. [PMID: 28676393 DOI: 10.1016/j.bbrc.2017.06.193] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 06/30/2017] [Indexed: 01/08/2023]
Abstract
The shape and position of mitochondria are intimately connected to both mitochondrial and cellular function. Mitochondrial anchors play a central role in mitochondrial positioning by exerting spatial, temporal, and contextual control over the cellular position of the organelle. Investigations into the molecular mechanisms of mitochondrial anchoring are still in the early stages, and we are beginning to appreciate the number and variety of anchors that exist. From the insight gained thus far, it is clear that mitochondrial anchoring has functional and physiological consequences that extend beyond mitochondrial positioning to other critical cellular processes.
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Affiliation(s)
- Lauren M Kraft
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Laura L Lackner
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
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13
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Insights on Heme Synthesis in the Malaria Parasite. Trends Parasitol 2017; 33:583-586. [PMID: 28495484 DOI: 10.1016/j.pt.2017.04.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 04/06/2017] [Accepted: 04/14/2017] [Indexed: 01/25/2023]
Abstract
The malaria parasite has a functional heme-biosynthetic pathway, although it can access host hemoglobin-heme. The heme pathway is dispensable for blood stages, but essential in the mosquito stages which do not acquire hemoglobin-heme. We propose that the blood stage parasites maintain a dynamic heme pool through multiple back-up mechanisms.
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14
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Chakraborty A. Understanding the biology of the Plasmodium falciparum apicoplast; an excellent target for antimalarial drug development. Life Sci 2016; 158:104-10. [DOI: 10.1016/j.lfs.2016.06.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/28/2016] [Accepted: 06/30/2016] [Indexed: 11/29/2022]
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15
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Three-dimensional analysis of morphological changes in the malaria parasite infected red blood cell by serial block-face scanning electron microscopy. J Struct Biol 2016; 193:162-171. [PMID: 26772147 DOI: 10.1016/j.jsb.2016.01.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 12/16/2015] [Accepted: 01/05/2016] [Indexed: 01/22/2023]
Abstract
The human malaria parasite, Plasmodium falciparum, exhibits morphological changes during the blood stage cycle in vertebrate hosts. Here, we used serial block-face scanning electron microscopy (SBF-SEM) to visualize the entire structures of P. falciparum-infected red blood cells (iRBCs) and to examine their morphological and volumetric changes at different stages. During developmental stages, the parasite forms Maurer's clefts and vesicles in the iRBC cytoplasm and knobs on the iRBC surface, and extensively remodels the iRBC structure for proliferation of the parasite. In our observations, the Maurer's clefts and vesicles in the P. falciparum-iRBCs, resembling the so-called tubovesicular network (TVN), were not connected to each other, and continuous membrane networks were not observed between the parasitophorous vacuole membrane (PVM) and the iRBC cytoplasmic membrane. In the volumetric analysis, the iRBC volume initially increased and then decreased to the end of the blood stage cycle. This suggests that it is necessary to absorb a substantial amount of nutrients from outside the iRBC during the initial stage, but to release waste materials from inside the iRBC at the multinucleate stage. Transportation of the materials may be through the iRBC membrane, rather than a special structure formed by the parasite, because there is no direct connection between the iRBC membrane and the parasite. These results provide new insights as to how the malaria parasite grows in the iRBC and remodels iRBC structure during developmental stages; these observation can serve as a baseline for further experiments on the effects of therapeutic agents on malaria.
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16
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Mailu BM, Li L, Arthur J, Nelson TM, Ramasamy G, Fritz-Wolf K, Becker K, Gardner MJ. Plasmodium Apicoplast Gln-tRNAGln Biosynthesis Utilizes a Unique GatAB Amidotransferase Essential for Erythrocytic Stage Parasites. J Biol Chem 2015; 290:29629-41. [PMID: 26318454 DOI: 10.1074/jbc.m115.655100] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Indexed: 01/25/2023] Open
Abstract
The malaria parasite Plasmodium falciparum apicoplast indirect aminoacylation pathway utilizes a non-discriminating glutamyl-tRNA synthetase to synthesize Glu-tRNA(Gln) and a glutaminyl-tRNA amidotransferase to convert Glu-tRNA(Gln) to Gln-tRNA(Gln). Here, we show that Plasmodium falciparum and other apicomplexans possess a unique heterodimeric glutamyl-tRNA amidotransferase consisting of GatA and GatB subunits (GatAB). We localized the P. falciparum GatA and GatB subunits to the apicoplast in blood stage parasites and demonstrated that recombinant GatAB converts Glu-tRNA(Gln) to Gln-tRNA(Gln) in vitro. We demonstrate that the apicoplast GatAB-catalyzed reaction is essential to the parasite blood stages because we could not delete the Plasmodium berghei gene encoding GatA in blood stage parasites in vivo. A phylogenetic analysis placed the split between Plasmodium GatB, archaeal GatE, and bacterial GatB prior to the phylogenetic divide between bacteria and archaea. Moreover, Plasmodium GatA also appears to have emerged prior to the bacterial-archaeal phylogenetic divide. Thus, although GatAB is found in Plasmodium, it emerged prior to the phylogenetic separation of archaea and bacteria.
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Affiliation(s)
- Boniface M Mailu
- From the Center for Infectious Disease Research, Seattle, Washington 98109
| | - Ling Li
- From the Center for Infectious Disease Research, Seattle, Washington 98109
| | - Jen Arthur
- From the Center for Infectious Disease Research, Seattle, Washington 98109
| | - Todd M Nelson
- From the Center for Infectious Disease Research, Seattle, Washington 98109
| | - Gowthaman Ramasamy
- From the Center for Infectious Disease Research, Seattle, Washington 98109
| | - Karin Fritz-Wolf
- the Department of Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University, Giessen 35392 Germany, and the Max-Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
| | - Katja Becker
- the Department of Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University, Giessen 35392 Germany, and
| | - Malcolm J Gardner
- From the Center for Infectious Disease Research, Seattle, Washington 98109, the Department of Global Health, University of Washington, Seattle, Washington 98195,
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17
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Knabe W, Washausen S. Early development of the nervous system of the eutherian <i>Tupaia belangeri</i>. Primate Biol 2015. [DOI: 10.5194/pb-2-25-2015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Abstract. The longstanding debate on the taxonomic status of Tupaia belangeri (Tupaiidae, Scandentia, Mammalia) has persisted in times of molecular biology and genetics. But way beyond that Tupaia belangeri has turned out to be a valuable and widely accepted animal model for studies in neurobiology, stress research, and virology, among other topics. It is thus a privilege to have the opportunity to provide an overview on selected aspects of neural development and neuroanatomy in Tupaia belangeri on the occasion of this special issue dedicated to Hans-Jürg Kuhn. Firstly, emphasis will be given to the optic system. We report rather "unconventional" findings on the morphogenesis of photoreceptor cells, and on the presence of capillary-contacting neurons in the tree shrew retina. Thereafter, network formation among directionally selective retinal neurons and optic chiasm development are discussed. We then address the main and accessory olfactory systems, the terminal nerve, the pituitary gland, and the cerebellum of Tupaia belangeri. Finally, we demonstrate how innovative 3-D reconstruction techniques helped to decipher and interpret so-far-undescribed, strictly spatiotemporally regulated waves of apoptosis and proliferation which pass through the early developing forebrain and eyes, midbrain and hindbrain, and through the panplacodal primordium which gives rise to all ectodermal placodes. Based on examples, this paper additionally wants to show how findings gained from the reported projects have influenced current neuroembryological and, at least partly, medical research.
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Peatey CL, Chavchich M, Chen N, Gresty KJ, Gray KA, Gatton ML, Waters NC, Cheng Q. Mitochondrial Membrane Potential in a Small Subset of Artemisinin-Induced Dormant Plasmodium falciparum Parasites In Vitro. J Infect Dis 2015; 212:426-34. [PMID: 25635122 DOI: 10.1093/infdis/jiv048] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 01/20/2015] [Indexed: 11/12/2022] Open
Abstract
Artemisinin-induced dormancy is a proposed mechanism for failures of monotherapy and is linked with artemisinin resistance in Plasmodium falciparum. The biological characterization and dynamics of dormant parasites are not well understood. Here we report that after dihydroartemisinin treatment in vitro, a small subset of morphologically dormant parasites was stained with rhodamine 123 (RH), a mitochondrial membrane potential marker, and persisted to recovery. RH-positive parasites sorted with fluorescence-activated cell sorting resumed growth at 10,000/well whereas RH-negative parasites failed to recover at 5 million/well. Furthermore, transcriptional activity for mitochondrial enzymes was detected only in RH-positive dormant parasites. Importantly, after treatment of dormant parasites with different concentrations of atovaquone, a mitochondrial inhibitor, the recovery of dormant parasites was delayed or stopped. This demonstrates that mitochondrial activity is critical for survival and regrowth of dormant parasites and that RH staining provides a means of identifying these parasites. These findings provide novel paths for studying and eradicating this dormant stage.
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Affiliation(s)
- Christopher L Peatey
- Drug Resistance and Diagnostics, Australian Army Malaria Institute Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute
| | - Marina Chavchich
- Drug Resistance and Diagnostics, Australian Army Malaria Institute
| | - Nanhua Chen
- Drug Resistance and Diagnostics, Australian Army Malaria Institute
| | - Karryn J Gresty
- Drug Resistance and Diagnostics, Australian Army Malaria Institute Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute
| | - Karen-Ann Gray
- Drug Resistance and Diagnostics, Australian Army Malaria Institute Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute
| | - Michelle L Gatton
- School of Public Health and Social Work, Queensland University of Technology, Brisbane, Australia
| | - Norman C Waters
- Walter Reed Army Institute of Research, Malaria Vaccine Branch, Military Malaria Research Program, Silver Spring, Maryland
| | - Qin Cheng
- Drug Resistance and Diagnostics, Australian Army Malaria Institute Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute
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19
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Affiliation(s)
- Paul A. Sigala
- Departments of Medicine and Molecular Microbiology and the Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, Missouri 63110; ,
| | - Daniel E. Goldberg
- Departments of Medicine and Molecular Microbiology and the Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, Missouri 63110; ,
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20
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Comparative ultrastructure and molecular phylogeny of Selenidium melongena n. sp. and S. terebellae Ray 1930 demonstrate niche partitioning in marine gregarine parasites (apicomplexa). Protist 2014; 165:493-511. [PMID: 24998785 DOI: 10.1016/j.protis.2014.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 05/29/2014] [Accepted: 05/30/2014] [Indexed: 11/21/2022]
Abstract
Gregarine apicomplexans are a diverse group of single-celled parasites that have feeding stages (trophozoites) and gamonts that generally inhabit the extracellular spaces of invertebrate hosts living in marine, freshwater, and terrestrial environments. Inferences about the evolutionary morphology of gregarine apicomplexans are being incrementally refined by molecular phylogenetic data, which suggest that several traits associated with the feeding cells of gregarines arose by convergent evolution. The study reported here supports these inferences by showing how molecular data reveals traits that are phylogenetically misleading within the context of comparative morphology alone. We examined the ultrastructure and molecular phylogenetic positions of two gregarine species isolated from the spaghetti worm Thelepus japonicus: Selenidium terebellaeRay 1930 and S. melongena n. sp. The ultrastructural traits of S. terebellae were very similar to other species of Selenidium sensu stricto, such as having vermiform trophozoites with an apical complex, few epicytic folds, and a dense array of microtubules underlying the trilayered pellicle. By contrast, S. melongena n. sp. lacked a comparably discrete assembly of subpellicular microtubules, instead employing a system of fibrils beneath the cell surface that supported a relatively dense array of helically arranged epicytic folds. Molecular phylogenetic analyses of small subunit rDNA sequences derived from single-cell PCR unexpectedly demonstrated that these two gregarines are close sister species. The ultrastructural differences between these two species were consistent with the fact that S. terebellae infects the inner lining of the host intestines, and S. melongena n. sp. primarily inhabits the coelom, infecting the outside wall of the host intestine. Altogether, these data demonstrate a compelling case of niche partitioning and associated morphological divergence in marine gregarine apicomplexans.
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21
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Marvin RG, Wolford JL, Kidd MJ, Murphy S, Ward J, Que EL, Mayer ML, Penner-Hahn JE, Haldar K, O'Halloran TV. Fluxes in "free" and total zinc are essential for progression of intraerythrocytic stages of Plasmodium falciparum. ACTA ACUST UNITED AC 2014; 19:731-41. [PMID: 22726687 DOI: 10.1016/j.chembiol.2012.04.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 03/27/2012] [Accepted: 04/16/2012] [Indexed: 02/07/2023]
Abstract
Dynamic fluxes in the concentration of ions and small molecules are fundamental features of cell signaling, differentiation, and development. Similar roles for fluxes in transition metal concentrations are less well established. Here, we show that massive zinc fluxes are essential in the infection cycle of an intracellular eukaryotic parasite. Using single-cell quantitative imaging, we show that growth of the blood-stage Plasmodium falciparum parasite requires acquisition of 30 million zinc atoms per erythrocyte before host cell rupture, corresponding to a 400% increase in total zinc concentration. Zinc accumulates in a freely available form in parasitophorous compartments outside the food vacuole, including mitochondria. Restriction of zinc availability via small molecule treatment causes a drop in mitochondrial membrane potential and severely inhibits parasite growth. Thus, extraordinary zinc acquisition and trafficking are essential for parasite development.
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Affiliation(s)
- Rebecca G Marvin
- Department of Chemistry and Chemistry of Life Processes Institute, Northwestern University, Evanston, IL 60208, USA
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22
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Chemical and genetic validation of thiamine utilization as an antimalarial drug target. Nat Commun 2013; 4:2060. [PMID: 23804074 DOI: 10.1038/ncomms3060] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 05/28/2013] [Indexed: 11/08/2022] Open
Abstract
Thiamine is metabolized into an essential cofactor for several enzymes. Here we show that oxythiamine, a thiamine analog, inhibits proliferation of the malaria parasite Plasmodium falciparum in vitro via a thiamine-related pathway and significantly reduces parasite growth in a mouse malaria model. Overexpression of thiamine pyrophosphokinase (the enzyme that converts thiamine into its active form, thiamine pyrophosphate) hypersensitizes parasites to oxythiamine by up to 1,700-fold, consistent with oxythiamine being a substrate for thiamine pyrophosphokinase and its conversion into an antimetabolite. We show that parasites overexpressing the thiamine pyrophosphate-dependent enzymes oxoglutarate dehydrogenase and pyruvate dehydrogenase are up to 15-fold more resistant to oxythiamine, consistent with the antimetabolite inactivating thiamine pyrophosphate-dependent enzymes. Our studies therefore validate thiamine utilization as an antimalarial drug target and demonstrate that a single antimalarial can simultaneously target several enzymes located within distinct organelles.
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23
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Mailu BM, Ramasamay G, Mudeppa DG, Li L, Lindner SE, Peterson MJ, DeRocher AE, Kappe SHI, Rathod PK, Gardner MJ. A nondiscriminating glutamyl-tRNA synthetase in the plasmodium apicoplast: the first enzyme in an indirect aminoacylation pathway. J Biol Chem 2013; 288:32539-32552. [PMID: 24072705 PMCID: PMC3820887 DOI: 10.1074/jbc.m113.507467] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/23/2013] [Indexed: 11/06/2022] Open
Abstract
The malaria parasite Plasmodium falciparum and related organisms possess a relict plastid known as the apicoplast. Apicoplast protein synthesis is a validated drug target in malaria because antibiotics that inhibit translation in prokaryotes also inhibit apicoplast protein synthesis and are sometimes used for malaria prophylaxis or treatment. We identified components of an indirect aminoacylation pathway for Gln-tRNA(Gln) biosynthesis in Plasmodium that we hypothesized would be essential for apicoplast protein synthesis. Here, we report our characterization of the first enzyme in this pathway, the apicoplast glutamyl-tRNA synthetase (GluRS). We expressed the recombinant P. falciparum enzyme in Escherichia coli, showed that it is nondiscriminating because it glutamylates both apicoplast tRNA(Glu) and tRNA(Gln), determined its kinetic parameters, and demonstrated its inhibition by a known bacterial GluRS inhibitor. We also localized the Plasmodium berghei ortholog to the apicoplast in blood stage parasites but could not delete the PbGluRS gene. These data show that Gln-tRNA(Gln) biosynthesis in the Plasmodium apicoplast proceeds via an essential indirect aminoacylation pathway that is reminiscent of bacteria and plastids.
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Affiliation(s)
- Boniface M Mailu
- From the Seattle Biomedical Research Institute, Seattle, Washington 98109
| | | | - Devaraja G Mudeppa
- the Department of Chemistry, University of Washington, Seattle, Washington 98195-1700
| | - Ling Li
- From the Seattle Biomedical Research Institute, Seattle, Washington 98109
| | - Scott E Lindner
- From the Seattle Biomedical Research Institute, Seattle, Washington 98109
| | - Megan J Peterson
- From the Seattle Biomedical Research Institute, Seattle, Washington 98109
| | - Amy E DeRocher
- From the Seattle Biomedical Research Institute, Seattle, Washington 98109
| | - Stefan H I Kappe
- From the Seattle Biomedical Research Institute, Seattle, Washington 98109,; the Department of Global Health, University of Washington, Seattle, Washington 98195
| | - Pradipsinh K Rathod
- the Department of Chemistry, University of Washington, Seattle, Washington 98195-1700; the Department of Global Health, University of Washington, Seattle, Washington 98195
| | - Malcolm J Gardner
- From the Seattle Biomedical Research Institute, Seattle, Washington 98109,; the Department of Global Health, University of Washington, Seattle, Washington 98195.
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24
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An FtsH protease is recruited to the mitochondrion of Plasmodium falciparum. PLoS One 2013; 8:e74408. [PMID: 24058559 PMCID: PMC3772908 DOI: 10.1371/journal.pone.0074408] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 08/01/2013] [Indexed: 11/19/2022] Open
Abstract
The two organelles, apicoplast and mitochondrion, of the malaria parasite Plasmodium falciparum have unique morphology in liver and blood stages; they undergo complex branching and looping prior to division and segregation into daughter merozoites. Little is known about the molecular processes and proteins involved in organelle biogenesis in the parasite. We report the identification of an AAA+/FtsH protease homolog (PfFtsH1) that exhibits ATP- and Zn(2+)-dependent protease activity. PfFtsH1 undergoes processing, forms oligomeric assemblies, and is associated with the membrane fraction of the parasite cell. Generation of a transfectant parasite line with hemagglutinin-tagged PfFtsH1, and immunofluorescence assay with anti-PfFtsH1 Ab demonstrated that the protein localises to P. falciparum mitochondria. Phylogenetic analysis and the single transmembrane region identifiable in PfFtsH1 suggest that it is an i-AAA like inner mitochondrial membrane protein. Expression of PfFtsH1 in Escherichia coli converted a fraction of bacterial cells into division-defective filamentous forms implying a sequestering effect of the Plasmodium factor on the bacterial homolog, indicative of functional conservation with EcFtsH. These results identify a membrane-associated mitochondrial AAA+/FtsH protease as a candidate regulatory protein for organelle biogenesis in P. falciparum.
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Next-generation sequencing reveals cryptic mtDNA diversity of Plasmodium relictum in the Hawaiian Islands. Parasitology 2013; 140:1741-50. [PMID: 23953131 DOI: 10.1017/s0031182013000905] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Next-generation 454 sequencing techniques were used to re-examine diversity of mitochondrial cytochrome b lineages of avian malaria (Plasmodium relictum) in Hawaii. We document a minimum of 23 variant lineages of the parasite based on single nucleotide transitional changes, in addition to the previously reported single lineage (GRW4). A new, publicly available portal (Integroomer) was developed for initial parsing of 454 datasets. Mean variant prevalence and frequency was higher in low elevation Hawaii Amakihi (Hemignathus virens) with Avipoxvirus-like lesions (P = 0·001), suggesting that the variants may be biologically distinct. By contrast, variant prevalence and frequency did not differ significantly among mid-elevation Apapane (Himatione sanguinea) with or without lesions (P = 0·691). The low frequency and the lack of detection of variants independent of GRW4 suggest that multiple independent introductions of P. relictum to Hawaii are unlikely. Multiple variants may have been introduced in heteroplasmy with GRW4 or exist within the tandem repeat structure of the mitochondrial genome. The discovery of multiple mitochondrial lineages of P. relictum in Hawaii provides a measure of genetic diversity within a geographically isolated population of this parasite and suggests the origins and evolution of parasite diversity may be more complicated than previously recognized.
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26
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Hanssen E, Dekiwadia C, Riglar DT, Rug M, Lemgruber L, Cowman AF, Cyrklaff M, Kudryashev M, Frischknecht F, Baum J, Ralph SA. Electron tomography of Plasmodium falciparum merozoites reveals core cellular events that underpin erythrocyte invasion. Cell Microbiol 2013; 15:1457-72. [PMID: 23461734 DOI: 10.1111/cmi.12132] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 02/25/2013] [Accepted: 02/27/2013] [Indexed: 11/29/2022]
Abstract
Erythrocyte invasion by merozoites forms of the malaria parasite is a key step in the establishment of human malaria disease. To date, efforts to understand cellular events underpinning entry have been limited to insights from non-human parasites, with no studies at sub-micrometer resolution undertaken using the most virulent human malaria parasite, Plasmodium falciparum. This leaves our understanding of the dynamics of merozoite sub-cellular compartments during infectionincomplete, in particular that of the secretory organelles. Using advances in P. falciparum merozoite isolation and new imaging techniques we present a three-dimensional study of invasion using electron microscopy, cryo-electron tomography and cryo-X-ray tomography. We describe the core architectural features of invasion and identify fusion between rhoptries at the commencement of invasion as a hitherto overlooked event that likely provides a critical step that initiates entry. Given the centrality of merozoite organelle proteins to vaccine development, these insights provide a mechanistic framework to understand therapeutic strategies targeted towards the cellular events of invasion.
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Affiliation(s)
- Eric Hanssen
- Advanced Microscopy Facility and Center of Excellence for Coherent X-ray Science, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Vic., 3010, Australia
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27
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Lemgruber L, Kudryashev M, Dekiwadia C, Riglar DT, Baum J, Stahlberg H, Ralph SA, Frischknecht F. Cryo-electron tomography reveals four-membrane architecture of the Plasmodium apicoplast. Malar J 2013; 12:25. [PMID: 23331966 PMCID: PMC3662607 DOI: 10.1186/1475-2875-12-25] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 01/15/2013] [Indexed: 12/21/2022] Open
Abstract
Background The apicoplast is a plastid organelle derived from a secondary endosymbiosis, containing biosynthetic pathways essential for the survival of apicomplexan parasites. The Toxoplasma apicoplast clearly possesses four membranes but in related Plasmodium spp. the apicoplast has variably been reported to have either three or four membranes. Methods Cryo-electron tomography was employed to image merozoites of Plasmodium falciparum and Plasmodium berghei frozen in their near-native state. Three-dimensional reconstructions revealed the number of apicoplast membranes and the association of the apicoplast with other organelles. Routine transmission electron microscopy of parasites preserved by high-pressure freezing followed by freeze substitution techniques was also used to analyse apicoplast morphology. Results Cryo-preserved parasites showed clearly four membranes surrounding the apicoplast. A wider gap between the second and third apicoplast membranes was frequently observed. The apicoplast was found in close proximity to the nucleus and to the rhoptries. The apicoplast matrix showed ribosome-sized particles and membranous whorls. Conclusions The Plasmodium apicoplast possesses four membranes, as do the apicoplasts of other apicomplexan parasites. This is consistent with a four-membraned secondary endosymbiotic plastid ancestor.
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Affiliation(s)
- Leandro Lemgruber
- Parasitology, Department of Infectious Diseases, University of Heidelberg Medical School, Im Neuenheimer Feld 324, Heidelberg 69120, Germany
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28
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van Dooren GG, Kennedy AT, McFadden GI. The use and abuse of heme in apicomplexan parasites. Antioxid Redox Signal 2012; 17:634-56. [PMID: 22320355 DOI: 10.1089/ars.2012.4539] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
SIGNIFICANCE Heme is an essential prosthetic group for most life on Earth. It functions in numerous cellular redox reactions, including in antioxidant defenses and at several stages of the electron transport chain in prokaryotes and eukaryotic mitochondria. Heme also functions as a sensor and transport molecule for gases such as oxygen. Heme is a complex organic molecule and can only be synthesized through a multienzyme pathway from simpler precursors. Most free-living organisms synthesize their own heme by a broadly conserved metabolic pathway. Parasites are adept at scavenging molecules from their hosts, and heme is no exception. RECENT ADVANCES In this review we examine recent advances in understanding heme usage and acquisition in Apicomplexa, a group of parasites that include the causative agents of malaria, toxoplasmosis, and several major parasites of livestock. CRITICAL ISSUES Heme is critical to the survival of Apicomplexa, although the functions of heme in these organisms remain poorly understood. Some Apicomplexa likely scavenge heme from their host organisms, while others retain the ability to synthesize heme. Surprisingly, some Apicomplexa may be able to both synthesize and scavenge heme. Several Apicomplexa live in intracellular environments that contain high levels of heme. Since heme is toxic at high concentrations, parasites must carefully regulate intracellular heme levels and develop mechanisms to detoxify excess heme. Indeed, drugs interfering with heme detoxification serve as major antimalarials. FUTURE DIRECTIONS Understanding heme requirements and regulation in apicomplexan parasites promises to reveal multiple targets for much-needed therapeutic intervention against these parasites.
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Affiliation(s)
- Giel G van Dooren
- Research School of Biology, Australian National University, Canberra, ACT, Australia.
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Kitamura K, Kishi-Itakura C, Tsuboi T, Sato S, Kita K, Ohta N, Mizushima N. Autophagy-related Atg8 localizes to the apicoplast of the human malaria parasite Plasmodium falciparum. PLoS One 2012; 7:e42977. [PMID: 22900071 PMCID: PMC3416769 DOI: 10.1371/journal.pone.0042977] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 07/16/2012] [Indexed: 01/24/2023] Open
Abstract
Autophagy is a membrane-mediated degradation process, which is governed by sequential functions of Atg proteins. Although Atg proteins are highly conserved in eukaryotes, protozoa possess only a partial set of Atg proteins. Nonetheless, almost all protozoa have the complete factors belonging to the Atg8 conjugation system, namely, Atg3, Atg4, Atg7, and Atg8. Here, we report the biochemical properties and subcellular localization of the Atg8 protein of the human malaria parasite Plasmodium falciparum (PfAtg8). PfAtg8 is expressed during intra-erythrocytic development and associates with membranes likely as a lipid-conjugated form. Fluorescence microscopy and immunoelectron microscopy show that PfAtg8 localizes to the apicoplast, a four membrane-bound non-photosynthetic plastid. Autophagosome-like structures are not observed in the erythrocytic stages. These data suggest that, although Plasmodium parasites have lost most Atg proteins during evolution, they use the Atg8 conjugation system for the unique organelle, the apicoplast.
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Affiliation(s)
- Kei Kitamura
- Department of Physiology and Cell Biology, Tokyo Medical and Dental University, Tokyo, Japan
- Department of Environmental Parasitology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Chieko Kishi-Itakura
- Department of Physiology and Cell Biology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takafumi Tsuboi
- Cell-Free Science and Technology Research Center and Venture Business Laboratory, Ehime University, Matsuyama, Ehime, Japan
| | - Shigeharu Sato
- Division of Parasitology, MRC National Institute for Medical Research, London, United Kingdom
| | - Kiyoshi Kita
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Nobuo Ohta
- Department of Environmental Parasitology, Tokyo Medical and Dental University, Tokyo, Japan
- * E-mail: (NO); (NM)
| | - Noboru Mizushima
- Department of Physiology and Cell Biology, Tokyo Medical and Dental University, Tokyo, Japan
- * E-mail: (NO); (NM)
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Soares Medeiros LC, De Souza W, Jiao C, Barrabin H, Miranda K. Visualizing the 3D architecture of multiple erythrocytes infected with Plasmodium at nanoscale by focused ion beam-scanning electron microscopy. PLoS One 2012; 7:e33445. [PMID: 22432024 PMCID: PMC3303842 DOI: 10.1371/journal.pone.0033445] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Accepted: 02/09/2012] [Indexed: 12/20/2022] Open
Abstract
Different methods for three-dimensional visualization of biological structures have been developed and extensively applied by different research groups. In the field of electron microscopy, a new technique that has emerged is the use of a focused ion beam and scanning electron microscopy for 3D reconstruction at nanoscale resolution. The higher extent of volume that can be reconstructed with this instrument represent one of the main benefits of this technique, which can provide statistically relevant 3D morphometrical data. As the life cycle of Plasmodium species is a process that involves several structurally complex developmental stages that are responsible for a series of modifications in the erythrocyte surface and cytoplasm, a high number of features within the parasites and the host cells has to be sampled for the correct interpretation of their 3D organization. Here, we used FIB-SEM to visualize the 3D architecture of multiple erythrocytes infected with Plasmodium chabaudi and analyzed their morphometrical parameters in a 3D space. We analyzed and quantified alterations on the host cells, such as the variety of shapes and sizes of their membrane profiles and parasite internal structures such as a polymorphic organization of hemoglobin-filled tubules. The results show the complex 3D organization of Plasmodium and infected erythrocyte, and demonstrate the contribution of FIB-SEM for the obtainment of statistical data for an accurate interpretation of complex biological structures.
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Affiliation(s)
- Lia Carolina Soares Medeiros
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratório de Membranas Transportadoras, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Wanderley De Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratório de Biotecnologia, Diretoria de Programas, Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (INMETRO), Xerém, Rio de Janeiro, Brazil
| | | | - Hector Barrabin
- Laboratório de Membranas Transportadoras, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Kildare Miranda
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratório de Biotecnologia, Diretoria de Programas, Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (INMETRO), Xerém, Rio de Janeiro, Brazil
- * E-mail:
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GFP-targeting allows visualization of the apicoplast throughout the life cycle of live malaria parasites. Biol Cell 2012; 101:415-30, 5 p following 430. [DOI: 10.1042/bc20080202] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Caballero MC, Pedroni MJ, Palmer GH, Suarez CE, Davitt C, Lau AOT. Characterization of acyl carrier protein and LytB in Babesia bovis apicoplast. Mol Biochem Parasitol 2011; 181:125-33. [PMID: 22057350 PMCID: PMC3278595 DOI: 10.1016/j.molbiopara.2011.10.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2011] [Revised: 10/12/2011] [Accepted: 10/18/2011] [Indexed: 01/09/2023]
Abstract
The apicoplast is a highly specialized organelle that mediates required functions in the growth and replication of apicomplexan parasites. Despite structural conservation of the apicoplast among different parasite genera and species, there are also critical differences in the metabolic requirements of different parasites and at different stages of the life cycle. To specifically compare apicoplast pathways between parasites that have both common and unique stages, we characterized the apicoplast in Babesia bovis, which has only intraerythrocytic asexual stages in the mammalian host, and compared it to that of Plasmodium falciparum, which has both asexual intraerythrocytic and hepatic stages. Specifically focusing on the type II fatty acid (FASII) and isoprenoid (MEP) biosynthesis pathways, we searched for pathway components and retention of active sites within the genome, localized key components [acyl carrier protein (ACP) and 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (LytB)] to the apicoplast, and demonstrated that the N-terminal bipartite signals of both proteins are required and sufficient for trafficking to the apicoplast lumen. Using specific pharmacologic inhibition, we demonstrated that MEP biosynthesis may be disrupted and its presence is required for intraerythrocytic growth of B. bovis asexual stages, consistent with the genomic pathway analysis and with its requirement in the asexual erythrocytic stages of P. falciparum. In contrast, FASII biosynthesis may or may not be present and specific drug targets did not have any inhibitory effect to B. bovis intraerythrocytic growth, which is consistent with the lack of requirement for P. falciparum intraerythrocytic growth. However, genomic analysis revealed the loss of FASII pathway components in B. bovis whereas the pathway is intact for P. falciparum but regulated to be expressed when needed (hepatic stages) and silent when not (intraerythrocytic stages). The results indicate specialized molding of apicoplast biosynthetic pathways to meet the requirements of individual apicomplexan parasites and their unique intracellular niches.
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Affiliation(s)
- Marina C Caballero
- Program of Genomics, Department of Veterinary Microbiology and Pathology and Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7040, USA
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Abstract
Parasites like malaria and Toxoplasma possess a vestigial plastid homologous to the chloroplasts of plants. The plastid (known as the apicoplast) is non-photosynthetic but retains many hallmarks of its ancestry including a circular genome that it synthesises proteins from and a suite of biosynthetic pathways of cyanobacterial origin. In this review, the discovery of the apicoplast and its integration, function and purpose are explored. New insights into the apicoplast fatty acid biosynthesis pathway and some novel roles of the apicoplast in vaccine development are reviewed.
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Stanway RR, Mueller N, Zobiak B, Graewe S, Froehlke U, Zessin PJM, Aepfelbacher M, Heussler VT. Organelle segregation into Plasmodium liver stage merozoites. Cell Microbiol 2011; 13:1768-82. [PMID: 21801293 DOI: 10.1111/j.1462-5822.2011.01657.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The liver stage of the Plasmodium parasite remains one of the most promising targets for intervention against malaria as it is clinically silent, precedes the symptomatic blood stage and represents a bottleneck in the parasite life cycle. However, many aspects of the development of the parasite during this stage are far from understood. During the liver stage, the parasite undergoes extensive replication, forming tens of thousands of infectious merozoites from each invading sporozoite. This implies a very efficient and accurate process of cytokinesis and thus also of organelle development and segregation. We have generated for the first time Plasmodium berghei double-fluorescent parasite lines, allowing visualization of the apicoplast, mitochondria and nuclei in live liver stage parasites. Using these we have seen that in parallel with nuclear division, the apicoplast and mitochondrion become two extensively branched and intertwining structures. The organelles then undergo impressive morphological and positional changes prior to cell division. To form merozoites, the parasite undergoes cytokinesis and the complex process of organelle development and segregation into the forming daughter merozoites could be analysed in detail using the newly generated transgenic parasites.
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Affiliation(s)
- Rebecca R Stanway
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Str. 74, 20359 Hamburg, Germany.
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Fernández Robledo JA, Caler E, Matsuzaki M, Keeling PJ, Shanmugam D, Roos DS, Vasta GR. The search for the missing link: a relic plastid in Perkinsus? Int J Parasitol 2011; 41:1217-29. [PMID: 21889509 DOI: 10.1016/j.ijpara.2011.07.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 07/27/2011] [Accepted: 07/28/2011] [Indexed: 12/11/2022]
Abstract
Perkinsus marinus (Phylum Perkinsozoa) is a protozoan parasite that has devastated natural and farmed oyster populations in the USA, significantly affecting the shellfish industry and the estuarine environment. The other two genera in the phylum, Parvilucifera and Rastrimonas, are parasites of microeukaryotes. The Perkinsozoa occupies a key position at the base of the dinoflagellate branch, close to its divergence from the Apicomplexa, a clade that includes parasitic protista, many harbouring a relic plastid. Thus, as a taxon that has also evolved toward parasitism, the Perkinsozoa has attracted the attention of biologists interested in the evolution of this organelle, both in its ultrastructure and the conservation, loss or transfer of its genes. A review of the recent literature reveals mounting evidence in support of the presence of a relic plastid in P. marinus, including the presence of multimembrane structures, characteristic metabolic pathways and proteins with a bipartite N-terminal extension. Further, these findings raise intriguing questions regarding the potential functions and unique adaptation of the putative plastid and/or plastid genes in the Perkinsozoa. In this review we analyse the above-mentioned evidence and evaluate the potential future directions and expected benefits of addressing such questions. Given the rapidly expanding molecular/genetic resources and methodological toolbox for Perkinsus spp., these organisms should complement the currently established models for investigating plastid evolution within the Chromalveolata.
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Affiliation(s)
- José A Fernández Robledo
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, IMET, Baltimore, MD 21202-3101, USA.
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Sato S. The apicomplexan plastid and its evolution. Cell Mol Life Sci 2011; 68:1285-96. [PMID: 21380560 PMCID: PMC3064897 DOI: 10.1007/s00018-011-0646-1] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 02/15/2011] [Accepted: 02/15/2011] [Indexed: 11/24/2022]
Abstract
Protistan species belonging to the phylum Apicomplexa have a non-photosynthetic secondary plastid-the apicoplast. Although its tiny genome and even the entire nuclear genome has been sequenced for several organisms bearing the organelle, the reason for its existence remains largely obscure. Some of the functions of the apicoplast, including housekeeping ones, are significantly different from those of other plastids, possibly due to the organelle's unique symbiotic origin.
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Affiliation(s)
- Shigeharu Sato
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, UK.
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Read M, Müller IB, Mitchell SL, Sims PFG, Hyde JE. Dynamic subcellular localization of isoforms of the folate pathway enzyme serine hydroxymethyltransferase (SHMT) through the erythrocytic cycle of Plasmodium falciparum. Malar J 2010; 9:351. [PMID: 21129192 PMCID: PMC3014972 DOI: 10.1186/1475-2875-9-351] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Accepted: 12/03/2010] [Indexed: 11/10/2022] Open
Abstract
Background The folate pathway enzyme serine hydroxymethyltransferase (SHMT) converts serine to glycine and 5,10-methylenetetrahydrofolate and is essential for the acquisition of one-carbon units for subsequent transfer reactions. 5,10-methylenetetrahydrofolate is used by thymidylate synthase to convert dUMP to dTMP for DNA synthesis. In Plasmodium falciparum an enzymatically functional SHMT (PfSHMTc) and a related, apparently inactive isoform (PfSHMTm) are found, encoded by different genes. Here, patterns of localization of the two isoforms during the parasite erythrocytic cycle are investigated. Methods Polyclonal antibodies were raised to PfSHMTc and PfSHMTm, and, together with specific markers for the mitochondrion and apicoplast, were employed in quantitative confocal fluorescence microscopy of blood-stage parasites. Results As well as the expected cytoplasmic occupancy of PfSHMTc during all stages, localization into the mitochondrion and apicoplast occurred in a stage-specific manner. Although early trophozoites lacked visible organellar PfSHMTc, a significant percentage of parasites showed such fluorescence during the mid-to-late trophozoite and schizont stages. In the case of the mitochondrion, the majority of parasites in these stages at any given time showed no marked PfSHMTc fluorescence, suggesting that its occupancy of this organelle is of limited duration. PfSHMTm showed a distinctly more pronounced mitochondrial location through most of the erythrocytic cycle and GFP-tagging of its N-terminal region confirmed the predicted presence of a mitochondrial signal sequence. Within the apicoplast, a majority of mitotic schizonts showed a marked concentration of PfSHMTc, whose localization in this organelle was less restricted than for the mitochondrion and persisted from the late trophozoite to the post-mitotic stages. PfSHMTm showed a broadly similar distribution across the cycle, but with a distinctive punctate accumulation towards the ends of elongating apicoplasts. In very late post-mitotic schizonts, both PfSHMTc and PfSHMTm were concentrated in the central region of the parasite that becomes the residual body on erythrocyte lysis and merozoite release. Conclusions Both PfSHMTc and PfSHMTm show dynamic, stage-dependent localization among the different compartments of the parasite and sequence analysis suggests they may also reversibly associate with each other, a factor that may be critical to folate cofactor function, given the apparent lack of enzymic activity of PfSHMTm.
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Affiliation(s)
- Martin Read
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
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Hanssen E, McMillan PJ, Tilley L. Cellular architecture of Plasmodium falciparum-infected erythrocytes. Int J Parasitol 2010; 40:1127-35. [DOI: 10.1016/j.ijpara.2010.04.012] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2010] [Revised: 04/15/2010] [Accepted: 04/15/2010] [Indexed: 01/11/2023]
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Nagaraj VA, Prasad D, Arumugam R, Rangarajan PN, Padmanaban G. Characterization of coproporphyrinogen III oxidase in Plasmodium falciparum cytosol. Parasitol Int 2010. [DOI: 10.1016/j.parint.2009.12.001 10.1016/j.molbiopara.2009.05.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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40
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van Doorn WG, Yoshimoto K. Role of chloroplasts and other plastids in ageing and death of plants and animals: a tale of Vishnu and Shiva. Ageing Res Rev 2010; 9:117-30. [PMID: 19720162 DOI: 10.1016/j.arr.2009.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2009] [Revised: 08/25/2009] [Accepted: 08/25/2009] [Indexed: 12/11/2022]
Abstract
Chloroplasts (chlorophyll-containing plastids) and other plastids are found in all plants and many animals. They are crucial to the survival of plants and most of the animals that harbour them. An example of a non-photosynthesizing plastid in animals is the apicoplast in the malaria-causing Plasmodium species, which is required for survival of the parasite. Many animals (such as sea slugs, sponges, reef corals, and clams) consume prey containing chloroplasts, or feed on algae. Some of these incorporate the chloroplasts from their food, or whole algal cells, into their own cells. Other species from these groups place algal cells between their own cells. Reef-building corals often lose their intracellular algae as a result of environmental changes, resulting in coral bleaching and death. The sensitivity of the chloroplast internal membranes to temperature stress is one of the reasons for coral death. Chloroplasts can also be a causal factor in the processes leading to whole-plant death, as the knockout of a gene encoding a chloroplast protein delayed the yellowing that proceeds death in tobacco plants. It is concluded that chloroplasts and other plastids are essential to individual survival in many species, including animals, and that they also play a role in triggering death in some plant and animal species.
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Seeber F, Soldati-Favre D. Metabolic Pathways in the Apicoplast of Apicomplexa. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 281:161-228. [DOI: 10.1016/s1937-6448(10)81005-6] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Hanssen E, Goldie KN, Tilley L. Ultrastructure of the asexual blood stages of Plasmodium falciparum. Methods Cell Biol 2010; 96:93-116. [PMID: 20869520 DOI: 10.1016/s0091-679x(10)96005-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Plasmodium falciparum is the most deadly of the human malaria parasites. The particular virulence of this species derives from its ability to subvert the physiology of its host during the blood stages of its development. The parasite grows and divides within erythrocytes, feeding on the hemoglobin, and remodeling its host cells so they adhere to blood vessel walls. The advent of molecular transfection technology, coupled with optical microscopy of fluorescent protein reporters, has greatly improved our understanding of the ways in which the malaria parasite alters its host cell. However, a full interpretation of the information from these studies requires similar advances in our knowledge of the ultrastructure of the parasite. Here we give an overview of different electron microscopy techniques that have revealed the fine structure of the parasite at different stages of development. We present data on some of the unusual organelles of P. falciparum, in particular, the membrane structures that are elaborated in the erythrocyte cytoplasm and are thought to play an important role in trafficking of virulence proteins. We present and discuss some of the exciting whole cell imaging techniques that represent a new frontier in the studies of parasite ultrastructure.
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Affiliation(s)
- Eric Hanssen
- Electron Microscopy Unit, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
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43
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Bhatt TK, Kapil C, Khan S, Jairajpuri MA, Sharma V, Santoni D, Silvestrini F, Pizzi E, Sharma A. A genomic glimpse of aminoacyl-tRNA synthetases in malaria parasite Plasmodium falciparum. BMC Genomics 2009; 10:644. [PMID: 20042123 PMCID: PMC2813244 DOI: 10.1186/1471-2164-10-644] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 12/31/2009] [Indexed: 12/14/2022] Open
Abstract
Background Plasmodium parasites are causative agents of malaria which affects >500 million people and claims ~2 million lives annually. The completion of Plasmodium genome sequencing and availability of PlasmoDB database has provided a platform for systematic study of parasite genome. Aminoacyl-tRNA synthetases (aaRSs) are pivotal enzymes for protein translation and other vital cellular processes. We report an extensive analysis of the Plasmodium falciparum genome to identify and classify aaRSs in this organism. Results Using various computational and bioinformatics tools, we have identified 37 aaRSs in P. falciparum. Our key observations are: (i) fraction of proteome dedicated to aaRSs in P. falciparum is very high compared to many other organisms; (ii) 23 out of 37 Pf-aaRS sequences contain signal peptides possibly directing them to different cellular organelles; (iii) expression profiles of Pf-aaRSs vary considerably at various life cycle stages of the parasite; (iv) several PfaaRSs posses very unusual domain architectures; (v) phylogenetic analyses reveal evolutionary relatedness of several parasite aaRSs to bacterial and plants aaRSs; (vi) three dimensional structural modelling has provided insights which could be exploited in inhibitor discovery against parasite aaRSs. Conclusion We have identified 37 Pf-aaRSs based on our bioinformatics analysis. Our data reveal several unique attributes in this protein family. We have annotated all 37 Pf-aaRSs based on predicted localization, phylogenetics, domain architectures and their overall protein expression profiles. The sets of distinct features elaborated in this work will provide a platform for experimental dissection of this family of enzymes, possibly for the discovery of novel drugs against malaria.
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Affiliation(s)
- Tarun Kumar Bhatt
- Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India.
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44
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Nagaraj VA, Prasad D, Arumugam R, Rangarajan PN, Padmanaban G. Characterization of coproporphyrinogen III oxidase in Plasmodium falciparum cytosol. Parasitol Int 2009; 59:121-7. [PMID: 20006984 DOI: 10.1016/j.parint.2009.12.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 11/28/2009] [Accepted: 12/07/2009] [Indexed: 10/20/2022]
Abstract
A unique hybrid pathway has been proposed for de novo heme biosynthesis in Plasmodium falciparum involving three different compartments of the parasite, namely mitochondrion, apicoplast and cytosol. While parasite mitochondrion and apicoplast have been shown to harbor key enzymes of the pathway, there has been no experimental evidence for the involvement of parasite cytosol in heme biosynthesis. In this study, a recombinant P. falciparum coproporphyrinogen III oxidase (rPfCPO) was produced in E. coli and confirmed to be active under aerobic conditions. rPfCPO behaved as a monomer of 61kDa molecular mass in gel filtration analysis. Immunofluorescence studies using antibodies to rPfCPO suggested that the enzyme was present in the parasite cytosol. These results were confirmed by detection of enzyme activity only in the parasite soluble fraction. Western blot analysis with anti-rPfCPO antibodies also revealed a 58kDa protein only in this fraction and not in the membrane fraction. The cytosolic presence of PfCPO provides evidence for a hybrid heme-biosynthetic pathway in the malarial parasite.
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45
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Tomova C, Humbel BM, Geerts WJC, Entzeroth R, Holthuis JCM, Verkleij AJ. Membrane Contact Sites between Apicoplast and ER inToxoplasma gondiiRevealed by Electron Tomography. Traffic 2009; 10:1471-80. [DOI: 10.1111/j.1600-0854.2009.00954.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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46
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Oborník M, Janouškovec J, Chrudimský T, Lukeš J. Evolution of the apicoplast and its hosts: From heterotrophy to autotrophy and back again. Int J Parasitol 2009; 39:1-12. [DOI: 10.1016/j.ijpara.2008.07.010] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 07/23/2008] [Accepted: 07/25/2008] [Indexed: 10/21/2022]
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Maeda-Sano K, Sato S, Ueda T, Yui R, Ito K, Hata M, Nakano A, Kita K, Murakami-Murofushi K, Sasaki N. Visualization of Mitochondrial and Apicoplast Nucleoids in the Human Malaria Parasite Plasmodium falciparum by SYBR Green I and PicoGreen Staining. CYTOLOGIA 2009. [DOI: 10.1508/cytologia.74.449] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | - Shigeharu Sato
- Division of Parasitology, MRC National Institute for Medical Research
| | - Takashi Ueda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo
| | - Ryoko Yui
- Division of Biological Science, Graduate School of Science, Nagoya University
| | - Kie Ito
- Division of Biology, Faculty of Science, Ochanomizu University
- Division of Biological Science, Graduate School of Science, Nagoya University
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo
| | - Masayuki Hata
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo
| | - Akihiko Nakano
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo
- RIKEN Advanced Science Institute
| | - Kiyoshi Kita
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo
| | | | - Narie Sasaki
- Division of Biological Science, Graduate School of Science, Nagoya University
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48
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Kim E, Archibald JM. Diversity and Evolution of Plastids and Their Genomes. PLANT CELL MONOGRAPHS 2008. [DOI: 10.1007/978-3-540-68696-5_1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Localisation of Plasmodium falciparum uroporphyrinogen III decarboxylase of the heme-biosynthetic pathway in the apicoplast and characterisation of its catalytic properties. Int J Parasitol 2008; 39:559-68. [PMID: 19041871 DOI: 10.1016/j.ijpara.2008.10.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 10/06/2008] [Accepted: 10/15/2008] [Indexed: 11/23/2022]
Abstract
Uroporphyrinogen decarboxylase (UROD) is a key enzyme in the heme-biosynthetic pathway and in Plasmodium falciparum it occupies a strategic position in the proposed hybrid pathway for heme biosynthesis involving shuttling of intermediates between different subcellular compartments in the parasite. In the present study, we demonstrate that an N-terminally truncated recombinant P. falciparum UROD (r(Delta)PfUROD) over-expressed and purified from Escherichia coli cells, as well as the native enzyme from the parasite were catalytically less efficient compared with the host enzyme, although they were similar in other enzyme parameters. Molecular modeling of PfUROD based on the known crystal structure of the human enzyme indicated that the protein manifests a distorted triose phosphate isomerase (TIM) barrel fold which is conserved in all the known structures of UROD. The parasite enzyme shares all the conserved or invariant amino acid residues at the active and substrate binding sites, but is rich in lysine residues compared with the host enzyme. Mutation of specific lysine residues corresponding to residues at the dimer interface in human UROD enhanced the catalytic efficiency of the enzyme and dimer stability indicating that the lysine rich nature and weak dimer interface of the wild-type PfUROD could be responsible for its low catalytic efficiency. PfUROD was localised to the apicoplast, indicating the requirement of additional mechanisms for transport of the product coproporphyrinogen to other subcellular sites for its further conversion and ultimate heme formation.
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50
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Apicoplast and mitochondrion in gametocytogenesis of Plasmodium falciparum. EUKARYOTIC CELL 2008; 8:128-32. [PMID: 18996983 DOI: 10.1128/ec.00267-08] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Live cell imaging of human malaria parasites Plasmodium falciparum during gametocytogenesis revealed that the apicoplast does not grow, whereas the mitochondrion undergoes remarkable morphological development. A close connection of the two organelles is consistently maintained. The apicoplast and mitochondrion are not components of the male gametes, suggesting maternal inheritance.
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