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Kwok ACM, Chan WS, Wong JTY. Dinoflagellate Amphiesmal Dynamics: Cell Wall Deposition with Ecdysis and Cellular Growth. Mar Drugs 2023; 21:md21020070. [PMID: 36827111 PMCID: PMC9959387 DOI: 10.3390/md21020070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/11/2023] [Accepted: 01/17/2023] [Indexed: 01/24/2023] Open
Abstract
Dinoflagellates are a major aquatic protist group with amphiesma, multiple cortical membranous "cell wall" layers that contain large circum-cortical alveolar sacs (AVs). AVs undergo extensive remodeling during cell- and life-cycle transitions, including ecdysal cysts (ECs) and resting cysts that are important in some harmful algal bloom initiation-termination. AVs are large cortical vesicular compartments, within which are elaborate cellulosic thecal plates (CTPs), in thecate species, and the pellicular layer (PL). AV-CTPs provide cellular mechanical protection and are targets of vesicular transport that are replaced during EC-swarmer cell transition, or with increased deposition during the cellular growth cycle. AV-PL exhibits dynamical-replacement with vesicular trafficking that are orchestrated with amphiesmal chlortetracycline-labeled Ca2+ stores signaling, integrating cellular growth with different modes of cell division cycle/progression. We reviewed the dynamics of amphiesma during different cell division cycle modes and life cycle stages, and its multifaceted regulations, focusing on the regulatory and functional readouts, including the coral-zooxanthellae interactions.
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Jimenez V, Miranda K, Ingrid A. The old and the new about the contractile vacuole of Trypanosoma cruzi. J Eukaryot Microbiol 2022; 69:e12939. [PMID: 35916682 PMCID: PMC11178379 DOI: 10.1111/jeu.12939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/27/2022] [Accepted: 07/27/2022] [Indexed: 11/28/2022]
Abstract
Osmoregulation is a conserved cellular process required for the survival of all organisms. In protists, the need for robust compensatory mechanisms that can maintain cell volume and tonicity within physiological range is even more relevant, as their life cycles are often completed in different environments. Trypanosoma cruzi, the protozoan pathogen responsible for Chagas disease, is transmitted by an insect vector to multiple types of mammalian hosts. The contractile vacuole complex (CVC) is an organelle that senses and compensates osmotic changes in the parasites, ensuring their survival upon ionic and osmotic challenges. Recent work shows that the contractile vacuole is also a key component of the secretory and endocytic pathways, regulating the selective targeting of surface proteins during differentiation. Here we summarize our current knowledge of the mechanisms involved in the osmoregulatory processes that take place in the vacuole, and we explore the new and exciting functions of this organelle in cell trafficking and signaling.
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Affiliation(s)
- Veronica Jimenez
- Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, California, USA
| | - Kildare Miranda
- Laboratorio de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Centro Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Augusto Ingrid
- Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, California, USA
- Laboratorio de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Plattner H. Ciliate Research. From Myth to Trendsetting Science. J Eukaryot Microbiol 2022; 69:e12926. [PMID: 35608570 DOI: 10.1111/jeu.12926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/18/2022] [Accepted: 05/18/2022] [Indexed: 11/28/2022]
Abstract
This special issue of the Journal of Eukaryotic Microbiology (JEM) summarizes achievements obtained by generations of researchers with ciliates in widely different disciplines. In fact, ciliates range among the first cells seen under the microscope centuries ago. Their beauty made them an object of scientia amabilis and their manifold reactions made them attractive for college experiments and finally challenged causal analyses at the cellular level. Some of this work was honored by a Nobel Prize. Some observations yielded a baseline for additional novel discoveries, occasionally facilitated by specific properties of some ciliates. This also offers some advantage in the exploration of closely related parasites (malaria). Articles contributed here by colleagues from all over the world encompass a broad spectrum of ciliate life, from genetics to evolution, from molecular cell biology to ecology, from intercellular signaling to epigenetics etc. This introductory chapter, largely based on my personal perception, aims at integrating work presented in this special issue of JEM into a broader historical context up to current research.
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Plattner H. Membrane Traffic and Ca 2+ -Signals in Ciliates. J Eukaryot Microbiol 2022; 69:e12895. [PMID: 35156735 DOI: 10.1111/jeu.12895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/01/2022] [Accepted: 02/01/2022] [Indexed: 11/30/2022]
Abstract
A Paramecium cell has as many types of membrane interactions as mammalian cells, as established with monoclonal antibodies by R. Allen and A. Fok. Since then, we have identified key-players, such as SNARE-proteins, Ca2+ -regulating proteins, including Ca2+ -channels, Ca2+ -pumps, Ca2+ -binding proteins of different affinity etc. at the molecular level, probed their function and localized them at the light and electron microscopy level. SNARE-proteins, in conjunction with a synaptotagmin-like Ca2+ -sensor protein, mediate membrane fusion. This interaction is additionally regulated by monomeric GTPases whose spectrum in Tetrahymena and Paramecium has been established by A. Turkewitz. As known from mammalian cells, GTPases are activated on membranes in conjunction with lumenal acidification by an H+ -ATPase. For these complex molecules we found in Paramecium an unsurpassed number of 17 a-subunit paralogs which connect the polymeric head and basis part, V1 and V0. (This multitude may reflect different local functional requirements.) Together with plasmalemmal Ca2+ -influx-channels, locally enriched intracellular InsP3 -type (InsP3 R, mainly in osmoregulatory system) and ryanodine receptor-like Ca2+ -release channels (ryanodine receptor-like proteins, RyR-LP), this complexity mediates Ca2+ signals for most flexible local membrane-to-membrane interactions. As we found, the latter channel types miss a substantial portion of the N-terminal part. Caffeine and 4-chloro-meta-cresol (the agent used to probe mutations of RyRs in man during surgery in malignant insomnia patients) initiate trichocyst exocytosis by activating Ca2+ -release channels type CRC-IV in the peripheral part of alveolar sacs. This is superimposed by Ca2+ -influx, i.e. a mechanism called "store-operated Ca2+ -entry" (SOCE). For the majority of key players, we have mapped paralogs throughout the Paramecium cell, with features in common or at variance in the different organelles participating in vesicle trafficking. Local values of free Ca2+ -concentration, [Ca2+ ]i , and their change, e.g. upon exocytosis stimulation, have been registered by flurochromes and chelator effects. In parallel we have registered release of Ca2+ from alveolar sacs by quenched-flow analysis combined with cryofixation and x-ray microanalysis.
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A Comparative Perspective on Functionally-Related, Intracellular Calcium Channels: The Insect Ryanodine and Inositol 1,4,5-Trisphosphate Receptors. Biomolecules 2021; 11:biom11071031. [PMID: 34356655 PMCID: PMC8301844 DOI: 10.3390/biom11071031] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/08/2021] [Accepted: 07/10/2021] [Indexed: 02/03/2023] Open
Abstract
Calcium (Ca2+) homeostasis is vital for insect development and metabolism, and the endoplasmic reticulum (ER) is a major intracellular reservoir for Ca2+. The inositol 1,4,5- triphosphate receptor (IP3R) and ryanodine receptor (RyR) are large homotetrameric channels associated with the ER and serve as two major actors in ER-derived Ca2+ supply. Most of the knowledge on these receptors derives from mammalian systems that possess three genes for each receptor. These studies have inspired work on synonymous receptors in insects, which encode a single IP3R and RyR. In the current review, we focus on a fundamental, common question: “why do insect cells possess two Ca2+ channel receptors in the ER?”. Through a comparative approach, this review covers the discovery of RyRs and IP3Rs, examines their structures/functions, the pathways that they interact with, and their potential as target sites in pest control. Although insects RyRs and IP3Rs share structural similarities, they are phylogenetically distinct, have their own structural organization, regulatory mechanisms, and expression patterns, which explains their functional distinction. Nevertheless, both have great potential as target sites in pest control, with RyRs currently being targeted by commercial insecticide, the diamides.
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Pérez-Gordones MC, Ramírez-Iglesias JR, Benaim G, Mendoza M. A store-operated Ca 2+-entry in Trypanosoma equiperdum: Physiological evidences of its presence. Mol Biochem Parasitol 2021; 244:111394. [PMID: 34216677 DOI: 10.1016/j.molbiopara.2021.111394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 06/26/2021] [Accepted: 06/28/2021] [Indexed: 02/06/2023]
Abstract
The Trypanosomatidae family encompasses many unicellular organisms responsible of several tropical diseases that affect humans and animals. Livestock tripanosomosis caused by Trypanosoma brucei brucei (T. brucei), Trypanosoma equiperdum (T. equiperdum) and Trypanosoma evansi (T. evansi), have a significant socio-economic impact and limit animal protein productivity throughout the intertropical zones of the world. Similarly, to all organisms, the maintenance of Ca2+ homeostasis is vital for these parasites, and the mechanism involved in the intracellular Ca2+ regulation have been widely described. However, the evidences related to the mechanisms responsible for the Ca2+ entry are scarce. Even more, to date the presence of a store-operated Ca2+ channel (SOC) has not been reported. Despite the apparent absence of Orai and STIM-like proteins in these parasites, in the present work we demonstrate the presence of a store-operated Ca2+-entry (SOCE) in T. equiperdum, using physiological techniques. This Ca2+-entry is induced by thapsigargin (TG) and 2,5-di-t-butyl-1,4-benzohydroquinone (BHQ), and inhibited by 2-aminoethoxydiphenyl borate (2APB). Additionally, the use of bioinformatics techniques allowed us to identify putative transient receptor potential (TRP) channels, present in members of the Trypanozoon family, which would be possible candidates responsible for the SOCE described in the present work in T. equiperdum.
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Affiliation(s)
- María C Pérez-Gordones
- Instituto de Biología Experimental (IBE), Universidad Central de Venezuela (UCV), Caracas, Venezuela
| | - José R Ramírez-Iglesias
- Group of Neglected and Emerging Diseases, Epidemiology and Biodiversity, Health Sciences Faculty, Universidad Internacional SEK (UISEK), Quito, Ecuador
| | - Gustavo Benaim
- Instituto de Biología Experimental (IBE), Universidad Central de Venezuela (UCV), Caracas, Venezuela; Instituto de Estudios Avanzados (IDEA), Caracas, Venezuela
| | - Marta Mendoza
- Centro de Estudios Biomédicos y Veterinarios, Instituto de Estudios Científicos y Tecnológicos (IDECYT), Universidad Nacional Experimental Simón Rodríguez, Caracas, Venezuela.
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Scarpelli PH, Pecenin MF, Garcia CRS. Intracellular Ca 2+ Signaling in Protozoan Parasites: An Overview with a Focus on Mitochondria. Int J Mol Sci 2021; 22:ijms22010469. [PMID: 33466510 PMCID: PMC7796463 DOI: 10.3390/ijms22010469] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/07/2020] [Accepted: 12/29/2020] [Indexed: 02/06/2023] Open
Abstract
Ca2+ signaling has been involved in controling critical cellular functions such as activation of proteases, cell death, and cell cycle control. The endoplasmatic reticulum plays a significant role in Ca2+ storage inside the cell, but mitochondria have long been recognized as a fundamental Ca2+ pool. Protozoan parasites such as Plasmodium falciparum, Toxoplasma gondii, and Trypanosoma cruzi display a Ca2+ signaling toolkit with similarities to higher eukaryotes, including the participation of mitochondria in Ca2+-dependent signaling events. This review summarizes the most recent knowledge in mitochondrial Ca2+ signaling in protozoan parasites, focusing on the mechanism involved in mitochondrial Ca2+ uptake by pathogenic protists.
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The remembrance of the things past: Conserved signalling pathways link protozoa to mammalian nervous system. Cell Calcium 2018; 73:25-39. [DOI: 10.1016/j.ceca.2018.04.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/01/2018] [Accepted: 04/01/2018] [Indexed: 12/13/2022]
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9
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Troczka BJ, Richardson E, Homem RA, Davies TGE. An analysis of variability in genome organisation of intracellular calcium release channels across insect orders. Gene 2018; 670:70-86. [PMID: 29792951 PMCID: PMC6026295 DOI: 10.1016/j.gene.2018.05.075] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 05/15/2018] [Accepted: 05/18/2018] [Indexed: 10/25/2022]
Abstract
Using publicly available genomic data, combined with RT-PCR validation, we explore structural genomic variation for two major ion channels across insect classes. We have manually curated ryanodine receptor (RyR) and inositol 1,4,5-trisphosphate receptor (IP3R) ORFs and their corresponding genomic structures from 26 different insects covering major insect orders. We found that, despite high protein identity for both RyRs (>75%) and IP3Rs (~67%), the overall complexity of the gene structure varies greatly between different insect orders with the simplest genes (fewest introns) found in Diptera and the most complex in Lepidoptera. Analysis of intron conservation patterns indicated that the majority of conserved introns are found close to the 5' end of the channels and in RyR around the highly conserved mutually exclusive splice site. Of the two channels the IP3Rs appear to have a less well conserved organisation with a greater overall number of unique introns seen between insect orders. We experimentally validated two of the manually curated ORFs for IP3Rs and confirmed an atypical (3799aa) IP3R receptor in Myzus persicae, which is approximately 1000 amino acids larger than previously reported for IP3Rs.
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Affiliation(s)
- Bartlomiej J Troczka
- Biointeractions and Crop Protection Department, Rothamsted Research, Harpenden AL5 2JQ, UK.
| | - Ewan Richardson
- Biointeractions and Crop Protection Department, Rothamsted Research, Harpenden AL5 2JQ, UK.
| | - Rafael A Homem
- Biointeractions and Crop Protection Department, Rothamsted Research, Harpenden AL5 2JQ, UK.
| | - T G Emyr Davies
- Biointeractions and Crop Protection Department, Rothamsted Research, Harpenden AL5 2JQ, UK.
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10
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Plattner H, Verkhratsky A. Inseparable tandem: evolution chooses ATP and Ca2+ to control life, death and cellular signalling. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0419. [PMID: 27377729 DOI: 10.1098/rstb.2015.0419] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2016] [Indexed: 01/01/2023] Open
Abstract
From the very dawn of biological evolution, ATP was selected as a multipurpose energy-storing molecule. Metabolism of ATP required intracellular free Ca(2+) to be set at exceedingly low concentrations, which in turn provided the background for the role of Ca(2+) as a universal signalling molecule. The early-eukaryote life forms also evolved functional compartmentalization and vesicle trafficking, which used Ca(2+) as a universal signalling ion; similarly, Ca(2+) is needed for regulation of ciliary and flagellar beat, amoeboid movement, intracellular transport, as well as of numerous metabolic processes. Thus, during evolution, exploitation of atmospheric oxygen and increasingly efficient ATP production via oxidative phosphorylation by bacterial endosymbionts were a first step for the emergence of complex eukaryotic cells. Simultaneously, Ca(2+) started to be exploited for short-range signalling, despite restrictions by the preset phosphate-based energy metabolism, when both phosphates and Ca(2+) interfere with each other because of the low solubility of calcium phosphates. The need to keep cytosolic Ca(2+) low forced cells to restrict Ca(2+) signals in space and time and to develop energetically favourable Ca(2+) signalling and Ca(2+) microdomains. These steps in tandem dominated further evolution. The ATP molecule (often released by Ca(2+)-regulated exocytosis) rapidly grew to be the universal chemical messenger for intercellular communication; ATP effects are mediated by an extended family of purinoceptors often linked to Ca(2+) signalling. Similar to atmospheric oxygen, Ca(2+) must have been reverted from a deleterious agent to a most useful (intra- and extracellular) signalling molecule. Invention of intracellular trafficking further increased the role for Ca(2+) homeostasis that became critical for regulation of cell survival and cell death. Several mutually interdependent effects of Ca(2+) and ATP have been exploited in evolution, thus turning an originally unholy alliance into a fascinating success story.This article is part of the themed issue 'Evolution brings Ca(2+) and ATP together to control life and death'.
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Affiliation(s)
- Helmut Plattner
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Alexei Verkhratsky
- Faculty of Biological Sciences, University of Manchester, Manchester M13 9PT, UK Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain University of Nizhny Novgorod, Nizhny Novgorod 603022, Russia
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11
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Plattner H. Evolutionary Cell Biology of Proteins from Protists to Humans and Plants. J Eukaryot Microbiol 2017; 65:255-289. [PMID: 28719054 DOI: 10.1111/jeu.12449] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 07/04/2017] [Accepted: 07/07/2017] [Indexed: 01/10/2023]
Abstract
During evolution, the cell as a fine-tuned machine had to undergo permanent adjustments to match changes in its environment, while "closed for repair work" was not possible. Evolution from protists (protozoa and unicellular algae) to multicellular organisms may have occurred in basically two lineages, Unikonta and Bikonta, culminating in mammals and angiosperms (flowering plants), respectively. Unicellular models for unikont evolution are myxamoebae (Dictyostelium) and increasingly also choanoflagellates, whereas for bikonts, ciliates are preferred models. Information accumulating from combined molecular database search and experimental verification allows new insights into evolutionary diversification and maintenance of genes/proteins from protozoa on, eventually with orthologs in bacteria. However, proteins have rarely been followed up systematically for maintenance or change of function or intracellular localization, acquirement of new domains, partial deletion (e.g. of subunits), and refunctionalization, etc. These aspects are discussed in this review, envisaging "evolutionary cell biology." Protozoan heritage is found for most important cellular structures and functions up to humans and flowering plants. Examples discussed include refunctionalization of voltage-dependent Ca2+ channels in cilia and replacement by other types during evolution. Altogether components serving Ca2+ signaling are very flexible throughout evolution, calmodulin being a most conservative example, in contrast to calcineurin whose catalytic subunit is lost in plants, whereas both subunits are maintained up to mammals for complex functions (immune defense and learning). Domain structure of R-type SNAREs differs in mono- and bikonta, as do Ca2+ -dependent protein kinases. Unprecedented selective expansion of the subunit a which connects multimeric base piece and head parts (V0, V1) of H+ -ATPase/pump may well reflect the intriguing vesicle trafficking system in ciliates, specifically in Paramecium. One of the most flexible proteins is centrin when its intracellular localization and function throughout evolution is traced. There are many more examples documenting evolutionary flexibility of translation products depending on requirements and potential for implantation within the actual cellular context at different levels of evolution. From estimates of gene and protein numbers per organism, it appears that much of the basic inventory of protozoan precursors could be transmitted to highest eukaryotic levels, with some losses and also with important additional "inventions."
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Affiliation(s)
- Helmut Plattner
- Department of Biology, University of Konstanz, P. O. Box M625, Konstanz, 78457, Germany
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12
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Garcia CRS, Alves E, Pereira PHS, Bartlett PJ, Thomas AP, Mikoshiba K, Plattner H, Sibley LD. InsP3 Signaling in Apicomplexan Parasites. Curr Top Med Chem 2017; 17:2158-2165. [PMID: 28137231 PMCID: PMC5490149 DOI: 10.2174/1568026617666170130121042] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 10/20/2016] [Accepted: 10/30/2016] [Indexed: 11/22/2022]
Abstract
Background:
Phosphoinositides (PIs) and their derivatives are essential cellular components that form the building blocks for cell membranes and regulate numerous cell functions. Specifically, the ability to generate myo-inositol 1,4,5-trisphosphate (InsP3) via phospholipase C (PLC) dependent hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) to InsP3 and diacylglycerol (DAG) initiates intracellular calcium signaling events representing a fundamental signaling mechanism dependent on PIs. InsP3 produced by PI turnover as a second messenger causes intracellular calcium release, especially from endoplasmic reticulum, by binding to the InsP3 receptor (InsP3R). Various PIs and the enzymes, such as phosphatidylinositol synthase and phosphatidylinositol 4-kinase, necessary for their turnover have been characterized in Apicomplexa, a large phylum of mostly commensal organisms that also includes several clinically relevant parasites. However, InsP3Rs have not been identified in genomes of apicomplexans, despite evidence that these parasites produce InsP3 that mediates intracellular Ca2+ signaling. Conclusion: Evidence to supporting IP3-dependent signaling cascades in apicomplexans suggests that they may harbor a primitive or non-canonical InsP3R. Understanding these pathways may be informative about early branching eukaryotes, where such signaling pathways also diverge from animal systems, thus identifying potential novel and essential targets for therapeutic intervention.
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Affiliation(s)
- Celia R S Garcia
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo. Sao Paulo 05508-090, Brazil
| | - Eduardo Alves
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo. Sao Paulo 05508-000, Brazil
| | - Pedro H S Pereira
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo. Sao Paulo 05508-090, Brazil,Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo. Sao Paulo 05508-000, Brazil
| | - Paula J Bartlett
- New Jersey Medical School, Rutgers, The State University of New Jersey, New Jersey, USA
| | - Andrew P Thomas
- New Jersey Medical School, Rutgers, The State University of New Jersey, New Jersey, USA
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute, Wako, Saitama, Japan
| | - Helmut Plattner
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - L David Sibley
- Department of Molecular Microbiology, Washington University Sch. Med., Saint Louis, USA
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Staudt E, Ramasamy P, Plattner H, Simon M. Differential subcellular distribution of four phospholipase C isoforms and secretion of GPI-PLC activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:3157-3168. [PMID: 27693913 DOI: 10.1016/j.bbamem.2016.09.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 09/04/2016] [Accepted: 09/27/2016] [Indexed: 12/11/2022]
Abstract
Phospholipase C (PLC) is an important enzyme of signal transduction pathways by generation of second messengers from membrane lipids. PLCs are also indicated to cleave glycosylphosphatidylinositol (GPI)-anchors of surface proteins thus releasing these into the environment. However, it remains unknown whether this enzymatic activity on the surface is due to distinct PLC isoforms in higher eukaryotes. Ciliates have, in contrast to other unicellular eukaryotes, multiple PLC isoforms as mammals do. Thus, Paramecium represents a perfect model to study subcellular distribution and potential surface activity of PLC isoforms. We have identified distinct subcellular localizations of four PLC isoforms indicating functional specialization. The association with different calcium release channels (CRCs) argues for distinct subcellular functions. They may serve as PI-PLCs in microdomains for local second messenger responses rather than free floating IP3. In addition, all isoforms can be found on the cell surface and they are found together with GPI-cleaved surface proteins in salt/ethanol washes of cells. We can moreover show them in medium supernatants of living cells where they have access to GPI-anchored surface proteins. Among the isoforms we cannot assign GPI-PLC activity to specific PLC isoforms; rather each PLC is potentially responsible for the release of GPI-anchored proteins from the surface.
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Affiliation(s)
- Emanuel Staudt
- Saarland University, Molecular Cell Dynamics, Centre for Human and Molecular Biology, Campus A2 4, 66123 Saarbrücken, Germany; University of Kaiserslautern, Department of Biology, Erwin-Schrödinger Straße, Building Nr. 14, 67663 Kaiserslautern, Germany
| | - Pathmanaban Ramasamy
- Saarland University, Molecular Cell Dynamics, Centre for Human and Molecular Biology, Campus A2 4, 66123 Saarbrücken, Germany
| | - Helmut Plattner
- University of Konstanz, Senior Research Group for Cell Biology and Ultrastructure Research, Department of Biology, 78457 Konstanz, Germany
| | - Martin Simon
- Saarland University, Molecular Cell Dynamics, Centre for Human and Molecular Biology, Campus A2 4, 66123 Saarbrücken, Germany.
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Plattner H. Trichocysts-Paramecium'sProjectile-like Secretory Organelles. J Eukaryot Microbiol 2016; 64:106-133. [DOI: 10.1111/jeu.12332] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/09/2016] [Accepted: 05/21/2016] [Indexed: 12/31/2022]
Affiliation(s)
- Helmut Plattner
- Department of Biology; University of Konstanz; PO Box M625 78457 Konstanz Germany
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15
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Plattner H. Signalling in ciliates: long- and short-range signals and molecular determinants for cellular dynamics. Biol Rev Camb Philos Soc 2015; 92:60-107. [PMID: 26487631 DOI: 10.1111/brv.12218] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 07/28/2015] [Accepted: 08/21/2015] [Indexed: 12/30/2022]
Abstract
In ciliates, unicellular representatives of the bikont branch of evolution, inter- and intracellular signalling pathways have been analysed mainly in Paramecium tetraurelia, Paramecium multimicronucleatum and Tetrahymena thermophila and in part also in Euplotes raikovi. Electrophysiology of ciliary activity in Paramecium spp. is a most successful example. Established signalling mechanisms include plasmalemmal ion channels, recently established intracellular Ca2+ -release channels, as well as signalling by cyclic nucleotides and Ca2+ . Ca2+ -binding proteins (calmodulin, centrin) and Ca2+ -activated enzymes (kinases, phosphatases) are involved. Many organelles are endowed with specific molecules cooperating in signalling for intracellular transport and targeted delivery. Among them are recently specified soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs), monomeric GTPases, H+ -ATPase/pump, actin, etc. Little specification is available for some key signal transducers including mechanosensitive Ca2+ -channels, exocyst complexes and Ca2+ -sensor proteins for vesicle-vesicle/membrane interactions. The existence of heterotrimeric G-proteins and of G-protein-coupled receptors is still under considerable debate. Serine/threonine kinases dominate by far over tyrosine kinases (some predicted by phosphoproteomic analyses). Besides short-range signalling, long-range signalling also exists, e.g. as firmly installed microtubular transport rails within epigenetically determined patterns, thus facilitating targeted vesicle delivery. By envisaging widely different phenomena of signalling and subcellular dynamics, it will be shown (i) that important pathways of signalling and cellular dynamics are established already in ciliates, (ii) that some mechanisms diverge from higher eukaryotes and (iii) that considerable uncertainties still exist about some essential aspects of signalling.
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Affiliation(s)
- Helmut Plattner
- Department of Biology, University of Konstanz, PO Box M625, 78457, Konstanz, Germany
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Plattner H. Molecular aspects of calcium signalling at the crossroads of unikont and bikont eukaryote evolution – The ciliated protozoan Paramecium in focus. Cell Calcium 2015; 57:174-85. [DOI: 10.1016/j.ceca.2014.12.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 12/01/2014] [Accepted: 12/02/2014] [Indexed: 12/19/2022]
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Plattner H, Verkhratsky A. The ancient roots of calcium signalling evolutionary tree. Cell Calcium 2015; 57:123-32. [DOI: 10.1016/j.ceca.2014.12.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 12/05/2014] [Indexed: 12/26/2022]
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18
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Evolution of acidic Ca2+ stores and their resident Ca2+-permeable channels. Cell Calcium 2015; 57:222-30. [DOI: 10.1016/j.ceca.2014.12.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 12/05/2014] [Accepted: 12/09/2014] [Indexed: 11/18/2022]
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Kumar U, Saier MH. Comparative Genomic Analysis of Integral Membrane Transport Proteins in Ciliates. J Eukaryot Microbiol 2014; 62:167-87. [DOI: 10.1111/jeu.12156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 04/23/2014] [Accepted: 04/28/2014] [Indexed: 11/25/2022]
Affiliation(s)
- Ujjwal Kumar
- Division of Biological Sciences; University of California at San Diego; La Jolla California
| | - Milton H. Saier
- Division of Biological Sciences; University of California at San Diego; La Jolla California
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Cai X, Wang X, Patel S, Clapham DE. Insights into the early evolution of animal calcium signaling machinery: a unicellular point of view. Cell Calcium 2014; 57:166-73. [PMID: 25498309 PMCID: PMC4355082 DOI: 10.1016/j.ceca.2014.11.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 11/18/2014] [Accepted: 11/24/2014] [Indexed: 11/15/2022]
Abstract
The basic principles of Ca(2+) regulation emerged early in prokaryotes. Ca(2+) signaling acquired more extensive and varied functions when life evolved into multicellular eukaryotes with intracellular organelles. Animals, fungi and plants display differences in the mechanisms that control cytosolic Ca(2+) concentrations. The aim of this review is to examine recent findings from comparative genomics of Ca(2+) signaling molecules in close unicellular relatives of animals and in common unicellular ancestors of animals and fungi. Also discussed are the evolution and origins of the sperm-specific CatSper channel complex, cation/Ca(2+) exchangers and four-domain voltage-gated Ca(2+) channels. Newly identified evolutionary evidence suggests that the distinct Ca(2+) signaling machineries in animals, plants and fungi likely originated from an ancient Ca(2+) signaling machinery prior to early eukaryotic radiation.
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Affiliation(s)
- Xinjiang Cai
- Division of Endocrinology, Metabolism and Nutrition, Department of Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08903, USA.
| | - Xiangbing Wang
- Division of Endocrinology, Metabolism and Nutrition, Department of Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08903, USA
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - David E Clapham
- Howard Hughes Medical Institute, Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
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Seo MD, Enomoto M, Ishiyama N, Stathopulos PB, Ikura M. Structural insights into endoplasmic reticulum stored calcium regulation by inositol 1,4,5-trisphosphate and ryanodine receptors. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:1980-91. [PMID: 25461839 DOI: 10.1016/j.bbamcr.2014.11.023] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Revised: 11/17/2014] [Accepted: 11/19/2014] [Indexed: 10/24/2022]
Abstract
The two major calcium (Ca²⁺) release channels on the sarco/endoplasmic reticulum (SR/ER) are inositol 1,4,5-trisphosphate and ryanodine receptors (IP3Rs and RyRs). They play versatile roles in essential cell signaling processes, and abnormalities of these channels are associated with a variety of diseases. Structural information on IP3Rs and RyRs determined using multiple techniques including X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy and cryo-electron microscopy (EM), has significantly advanced our understanding of the mechanisms by which these Ca²⁺ release channels function under normal and pathophysiological circumstances. In this review, structural advances on the understanding of the mechanisms of IP3R and RyR function and dysfunction are summarized. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.
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Affiliation(s)
- Min-Duk Seo
- Department of Molecular Science and Technology, Ajou University, Suwon, Gyeonggi 443-749, Republic of Korea; College of Pharmacy, Ajou University, Suwon, Gyeonggi 443-749, Republic of Korea
| | - Masahiro Enomoto
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Noboru Ishiyama
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Mitsuhiko Ikura
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON M5G 1L7, Canada.
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Plattner H. Calcium signalling in the ciliated protozoan model, Paramecium: strict signal localisation by epigenetically controlled positioning of different Ca²⁺-channels. Cell Calcium 2014; 57:203-13. [PMID: 25277862 DOI: 10.1016/j.ceca.2014.09.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 09/01/2014] [Indexed: 11/17/2022]
Abstract
The Paramecium tetraurelia cell is highly organised, with regularly spaced elements pertinent to Ca(2+) signalling under epigenetic control. Vesicles serving as stationary Ca(2+) stores or undergoing trafficking contain Ca(2+)-release channels (PtCRCs) which, according to sequence and domain comparison, are related either to inositol 1,4,5-trisphosphate (InsP3) receptors (IP3R) or to ryanodine receptor-like proteins (RyR-LP) or to both, with intermediate characteristics or deviation from conventional domain structure. Six groups of such PtCRCs have been found. The ryanodine-InsP3-receptor homology (RIH) domain is not always recognisable, in contrast to the channel domain with six trans-membrane domains and the pore between transmembrane domain 5 and 6. Two CRC subtypes tested more closely, PtCRC-II and PtCRC-IV, with and without an InsP3-binding domain, reacted to InsP3 and to caffeine, respectively, and hence represent IP3Rs and RyR-LPs. IP3Rs occur in the contractile vacuole complex where they allow for stochastic constitutive Ca(2+) reflux into the cytosol. RyR-LPs are localised to cortical Ca(2+) stores; they are engaged in dense core-secretory vesicle exocytosis by Ca(2+) release, superimposed by Ca(2+)-influx via non-ciliary Ca(2+)-channels. One or two different types of PtCRCs also occur in other vesicles undergoing trafficking. Since the PtCRCs described combine different features they are considered derivatives of primitive precursors. The highly regular, epigenetically controlled design of a Paramecium cell allows it to make Ca(2+) available very locally, in a most efficient way, along predetermined trafficking pathways, including regulation of exocytosis, endocytosis, phagocytosis and recycling phenomena. The activity of cilia is also regulated by Ca(2+), yet independently from any CRCs, by de- and hyperpolarisation of the cell membrane potential.
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Affiliation(s)
- Helmut Plattner
- Department of Biology, University of Konstanz, P.O. Box M625, 78457 Konstanz, Germany.
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Echevarria ML, Wolfe GV, Strom SL, Taylor AR. Connecting alveolate cell biology with trophic ecology in the marine plankton using the ciliateFavellaas a model. FEMS Microbiol Ecol 2014; 90:18-38. [DOI: 10.1111/1574-6941.12382] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 07/11/2014] [Accepted: 07/13/2014] [Indexed: 11/30/2022] Open
Affiliation(s)
- Michael L. Echevarria
- Department of Biology and Marine Biology; University of North Carolina Wilmington; Wilmington NC USA
| | - Gordon V. Wolfe
- Department Biological Sciences; California State University of Chico; Chico CA USA
| | - Suzanne L. Strom
- Shannon Point Marine Center; Western Washington University; Anacortes WA USA
| | - Alison R. Taylor
- Department of Biology and Marine Biology; University of North Carolina Wilmington; Wilmington NC USA
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Simon M, Plattner H. Unicellular Eukaryotes as Models in Cell and Molecular Biology. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 309:141-98. [DOI: 10.1016/b978-0-12-800255-1.00003-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Abstract
Ca(2+)-signaling pathways and intracellular Ca(2+) channels are present in protozoa. Ancient origin of inositol 1,4,5-trisphosphate receptors (IP3Rs) and other intracellular channels predates the divergence of animals and fungi as evidenced by their presence in the choanoflagellate Monosiga brevicollis, the closest known relative to metazoans. The first protozoan IP3R cloned, from the ciliate Paramecium, displays strong sequence similarity to the rat type 3 IP3R. This ciliate has a large number of IP3- and ryanodine(Ry)-like receptors in six subfamilies suggesting the evolutionary adaptation to local requirements for an expanding diversification of vesicle trafficking. IP3Rs have also been functionally characterized in trypanosomatids, where they are essential for growth, differentiation, and establishment of infection. The presence of the mitochondrial calcium uniporter (MCU) in a number of protozoa indicates that mitochondrial regulation of Ca(2+) signaling is also an early appearance in evolution, and contributed to the discovery of the molecular nature of this channel in mammalian cells. There is only sequence evidence for the occurrence of two-pore channels (TPCs), transient receptor potential Ca(2+) channels (TRPCs) and intracellular mechanosensitive Ca(2+)-channels in Paramecium and in parasitic protozoa.
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Plattner H. Calcium regulation in the protozoan model, Paramecium tetraurelia. J Eukaryot Microbiol 2013; 61:95-114. [PMID: 24001309 DOI: 10.1111/jeu.12070] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 06/21/2013] [Accepted: 06/28/2013] [Indexed: 01/24/2023]
Abstract
Early in eukaryotic evolution, the cell has evolved a considerable inventory of proteins engaged in the regulation of intracellular Ca(2+) concentrations, not only to avoid toxic effects but beyond that to exploit the signaling capacity of Ca(2+) by small changes in local concentration. Among protozoa, the ciliate Paramecium may now be one of the best analyzed models. Ciliary activity and exo-/endocytosis are governed by Ca(2+) , the latter by Ca(2+) mobilization from alveolar sacs and a superimposed store-operated Ca(2+) -influx. Paramecium cells possess plasma membrane- and endoplasmic reticulum-resident Ca(2+) -ATPases/pumps (PMCA, SERCA), a variety of Ca(2+) influx channels, including mechanosensitive and voltage-dependent channels in the plasma membrane, furthermore a plethora of Ca(2+) -release channels (CRC) of the inositol 1,4,5-trisphosphate and ryanodine receptor type in different compartments, notably the contractile vacuole complex and the alveolar sacs, as well as in vesicles participating in vesicular trafficking. Additional types of CRC probably also occur but they have not been identified at a molecular level as yet, as is the equivalent of synaptotagmin as a Ca(2+) sensor for exocytosis. Among established targets and sensors of Ca(2+) in Paramecium are calmodulin, calcineurin, as well as Ca(2+) /calmodulin-dependent protein kinases, all with multiple functions. Thus, basic elements of Ca(2+) signaling are available for Paramecium.
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Affiliation(s)
- Helmut Plattner
- Department of Biology, University of Konstanz, P.O. Box 5544, 78457, Konstanz, Germany
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Plattner H. The contractile vacuole complex of protists--new cues to function and biogenesis. Crit Rev Microbiol 2013; 41:218-27. [PMID: 23919298 DOI: 10.3109/1040841x.2013.821650] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The contractile vacuole complex (CVC) of freshwater protists sequesters the excess of water and ions (Ca(2+)) for exocytosis cycles at the pore. Sequestration is based on a chemiosmotic proton gradient produced by a V-type H(+)-ATPase. So far, many pieces of information available have not been combined to a comprehensive view on CVC biogenesis and function. One main function now appears as follows. Ca(2+)-release channels, type inositol 1,4,5-trisphosphate receptors (InsP3R), may serve for fine-tuning of local cytosolic Ca(2+) concentration and mediate numerous membrane-to-membrane interactions within the tubular spongiome meshwork. Such activity is suggested by the occurrence of organelle-specific soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) and Ras-related in brain (Rab) proteins, which may regulate functional requirements. For tubulation, F-Bin-amphiphysin-Rvs (F-BAR) proteins are available. In addition, there is indirect evidence for the occurrence of H(+)/Ca(2+) exchangers (to sequester Ca(2+)) and mechanosensitive Ca(2+)-channels (for signaling the filling sate). The periodic activity of the CVC may be regulated by the mechanosensitive Ca(2+)-channels. Such channels are known to colocalize with and to be functionally supported by stomatins, which were recently detected in the CVC. A Kif18-related kinesin motor protein might control the length of radial arms. Two additional InsP3-related channels and several SNAREs are associated with the pore. De novo organelle biogenesis occurs under epigenetic control during mitotic activity and may involve the assembly of γ-tubulin, centrin, calmodulin and a never in mitosis A-type (NIMA) kinase - components also engaged in mitotic processes.
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Affiliation(s)
- Helmut Plattner
- Department of Biology, University of Konstanz , Konstanz , Germany
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Abstract
Early in evolution, Ca(2+) emerged as the most important second messenger for regulating widely different cellular functions. In eukaryotic cells Ca(2+) signals originate from several sources, i.e. influx from the outside medium, release from internal stores or from both. In mammalian cells, Ca(2+)-release channels represented by inositol 1,4,5-trisphosphate receptors and ryanodine receptors (InsP3R and RyR, respectively) are the most important. In unicellular organisms and plants, these channels are characterised with much less precision. In the ciliated protozoan, Paramecium tetraurelia, 34 molecularly distinct Ca(2+)-release channels that can be grouped in six subfamilies, based on criteria such as domain structure, pore, selectivity filter and activation mechanism have been identified. Some of these channels are genuine InsP3Rs and some are related to RyRs. Others show some--but not all--features that are characteristic for one or the other type of release channel. Localisation and gene silencing experiments revealed widely different--yet distinct--localisation, activation and functional engagement of the different Ca(2+)-release channels. Here, we shall discuss early evolutionary routes of Ca(2+)-release machinery in protozoa and demonstrate that detailed domain analyses and scrutinised functional analyses are instrumental for in-depth evolutionary mapping of Ca(2+)-release channels in unicellular organisms.
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Affiliation(s)
- Helmut Plattner
- Faculty of Biology, University of Konstanz, 78457 Konstanz, Germany.
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Zhang D, Liu X, Chan JD, Marchant JS. Characterization of a flatworm inositol (1,4,5) trisphosphate receptor (IP₃R) reveals a role in reproductive physiology. Cell Calcium 2013; 53:307-14. [PMID: 23481272 PMCID: PMC3665645 DOI: 10.1016/j.ceca.2013.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 01/22/2013] [Accepted: 01/29/2013] [Indexed: 11/15/2022]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP₃Rs) are intracellular Ca²⁺ channels that elevate cytoplasmic Ca²⁺ in response to the second messenger IP3. Here, we describe the identification and in vivo functional characterization of the planarian IP₃R, the first intracellular Ca²⁺ channel to be defined in flatworms. A single IP₃R gene in Dugesia japonica encoded a 2666 amino acid protein (Dj.IP₃R) that shared well conserved structural features with vertebrate IP₃R counterparts. Expression of an NH₂-terminal Dj.IP₃R region (amino acid residues 223-585) recovered high affinity ³H-IP₃ binding (0.9±0.1 nM) which was abolished by a single point mutation of an arginine residue (R495L) important for IP₃ coordination. In situ hybridization revealed that Dj.IP₃R mRNA was most strongly expressed in the pharynx and optical nerve system as well as the reproductive system in sexualized planarians. Consistent with this observed tissue distribution, in vivo RNAi of Dj.IP₃R resulted in a decreased egg-laying behavior suggesting Dj.IP₃R plays an upstream role in planarian reproductive physiology.
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Affiliation(s)
- Dan Zhang
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
| | - Xiaolong Liu
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
| | - John D. Chan
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
| | - Jonathan S. Marchant
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
- The Stem Cell Institute, University of Minnesota Medical School, MN 55455, USA
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Hashimoto M, Enomoto M, Morales J, Kurebayashi N, Sakurai T, Hashimoto T, Nara T, Mikoshiba K. Inositol 1,4,5-trisphosphate receptor regulates replication, differentiation, infectivity and virulence of the parasitic protist Trypanosoma cruzi. Mol Microbiol 2013; 87:1133-50. [PMID: 23320762 DOI: 10.1111/mmi.12155] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/09/2013] [Indexed: 11/26/2022]
Abstract
In animals, inositol 1,4,5-trisphosphate receptors (IP3 Rs) are ion channels that play a pivotal role in many biological processes by mediating Ca(2+) release from the endoplasmic reticulum. Here, we report the identification and characterization of a novel IP3 R in the parasitic protist, Trypanosoma cruzi, the pathogen responsible for Chagas disease. DT40 cells lacking endogenous IP3 R genes expressing T. cruzi IP3 R (TcIP3 R) exhibited IP3 -mediated Ca(2+) release from the ER, and demonstrated receptor binding to IP3 . TcIP3 R was expressed throughout the parasite life cycle but the expression level was much lower in bloodstream trypomastigotes than in intracellular amastigotes or epimastigotes. Disruption of two of the three TcIP3 R gene loci led to the death of the parasite, suggesting that IP3 R is essential for T. cruzi. Parasites expressing reduced or increased levels of TcIP3 R displayed defects in growth, transformation and infectivity, indicating that TcIP3 R is an important regulator of the parasite's life cycle. Furthermore, mice infected with T. cruzi expressing reduced levels of TcIP3 R exhibited a reduction of disease symptoms, indicating that TcIP3 R is an important virulence factor. Combined with the fact that the primary structure of TcIP3 R has low similarity to that of mammalian IP3 Rs, TcIP3 R is a promising drug target for Chagas disease.
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Affiliation(s)
- Muneaki Hashimoto
- Department of Molecular and Cellular Parasitology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
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Identification, localization, and functional implications of the microdomain-forming stomatin family in the ciliated protozoan Paramecium tetraurelia. EUKARYOTIC CELL 2013; 12:529-44. [PMID: 23376944 DOI: 10.1128/ec.00324-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The SPFH protein superfamily is assumed to occur universally in eukaryotes, but information from protozoa is scarce. In the Paramecium genome, we found only Stomatins, 20 paralogs grouped in 8 families, STO1 to STO8. According to cDNA analysis, all are expressed, and molecular modeling shows the typical SPFH domain structure for all subgroups. For further analysis we used family-specific sequences for fluorescence and immunogold labeling, gene silencing, and functional tests. With all family members tested, we found a patchy localization at/near the cell surface and on vesicles. The Sto1p and Sto4p families are also associated with the contractile vacuole complex. Sto4p also makes puncta on some food vacuoles and is abundant on vesicles recycling from the release site of spent food vacuoles to the site of nascent food vacuole formation. Silencing of the STO1 family reduces mechanosensitivity (ciliary reversal upon touching an obstacle), thus suggesting relevance for positioning of mechanosensitive channels in the plasmalemma. Silencing of STO4 members increases pulsation frequency of the contractile vacuole complex and reduces phagocytotic activity of Paramecium cells. In summary, Sto1p and Sto4p members seem to be involved in positioning specific superficial and intracellular microdomain-based membrane components whose functions may depend on mechanosensation (extracellular stimuli and internal osmotic pressure).
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Contractile Vacuole Complex—Its Expanding Protein Inventory. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 306:371-416. [DOI: 10.1016/b978-0-12-407694-5.00009-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Schönemann B, Bledowski A, Sehring IM, Plattner H. A set of SNARE proteins in the contractile vacuole complex of Paramecium regulates cellular calcium tolerance and also contributes to organelle biogenesis. Cell Calcium 2012; 53:204-16. [PMID: 23280185 DOI: 10.1016/j.ceca.2012.11.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 11/15/2012] [Accepted: 11/29/2012] [Indexed: 02/07/2023]
Abstract
The contractile vacuole complex (CVC) of freshwater protists serves the extrusion of water and ions, including Ca(2+). No vesicle trafficking based on SNAREs has been detected so far in any CVC. SNAREs (soluble NSF [N-ethylmaleimide sensitive factor] attachment protein receptors) are required for membrane-to-membrane interaction, i.e. docking and fusion also in Paramecium. We have identified three v-/R- and three t/Q-SNAREs selectively in the CVC. Posttranscriptional silencing of Syb2, Syb6 or Syx2 slows down the pumping cycle; silencing of the latter two also causes vacuole swelling. Increase in extracellular Ca(2+) after Syb2, Syb6 or Syx2 silencing causes further swelling of the contractile vacuole and deceleration of its pulsation. Silencing of Syx14 or Syx15 entails lethality in the Ca(2+) stress test. Thus, the effects of silencing strictly depend on the type of the silenced SNARE and on the concentration of Ca(2+) in the medium. This shows the importance of organelle-resident SNARE functions (which may encompass the vesicular delivery of other organelle-resident proteins) for Ca(2+) tolerance. A similar principle may be applicable also to the CVC in widely different unicellular organisms. In addition, in Paramecium, silencing particularly of Syx6 causes aberrant positioning of the CVC during de novo biogenesis before cytokinesis.
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Holder AA, Mohd Ridzuan MA, Green JL. Calcium dependent protein kinase 1 and calcium fluxes in the malaria parasite. Microbes Infect 2012; 14:825-30. [PMID: 22584104 DOI: 10.1016/j.micinf.2012.04.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 04/11/2012] [Accepted: 04/11/2012] [Indexed: 01/20/2023]
Abstract
Calcium dependent protein kinases (CDPKs) are found only in plants and alveolates and are distinguished from other kinases by an activation domain that binds calcium directly. Plants contain families of these kinases and their functions are modulated by post translational modifications as well as calcium activation. Apicomplexan parasites also contain CDPK families and this review is focused on CDPK1 in Plasmodium spp. This enzyme has been implicated in parasite motility and host cell invasion and at least two substrates associated with the actomyosin motor complex have been identified. By analogy with the plant CDPKs we propose that its activity is modulated both by post translational modifications and by its subcellular location in a compartment within the parasite's pellicle, which may regulate the calcium concentration required for activation.
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Affiliation(s)
- Anthony A Holder
- Division of Parasitology, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK.
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Plattner H, Sehring IM, Mohamed IK, Miranda K, De Souza W, Billington R, Genazzani A, Ladenburger EM. Calcium signaling in closely related protozoan groups (Alveolata): non-parasitic ciliates (Paramecium, Tetrahymena) vs. parasitic Apicomplexa (Plasmodium, Toxoplasma). Cell Calcium 2012; 51:351-82. [PMID: 22387010 DOI: 10.1016/j.ceca.2012.01.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 01/10/2012] [Accepted: 01/12/2012] [Indexed: 12/20/2022]
Abstract
The importance of Ca2+-signaling for many subcellular processes is well established in higher eukaryotes, whereas information about protozoa is restricted. Recent genome analyses have stimulated such work also with Alveolates, such as ciliates (Paramecium, Tetrahymena) and their pathogenic close relatives, the Apicomplexa (Plasmodium, Toxoplasma). Here we compare Ca2+ signaling in the two closely related groups. Acidic Ca2+ stores have been characterized in detail in Apicomplexa, but hardly in ciliates. Two-pore channels engaged in Ca2+-release from acidic stores in higher eukaryotes have not been stingently characterized in either group. Both groups are endowed with plasma membrane- and endoplasmic reticulum-type Ca2+-ATPases (PMCA, SERCA), respectively. Only recently was it possible to identify in Paramecium a number of homologs of ryanodine and inositol 1,3,4-trisphosphate receptors (RyR, IP3R) and to localize them to widely different organelles participating in vesicle trafficking. For Apicomplexa, physiological experiments suggest the presence of related channels although their identity remains elusive. In Paramecium, IP3Rs are constitutively active in the contractile vacuole complex; RyR-related channels in alveolar sacs are activated during exocytosis stimulation, whereas in the parasites the homologous structure (inner membrane complex) may no longer function as a Ca2+ store. Scrutinized comparison of the two closely related protozoan phyla may stimulate further work and elucidate adaptation to parasitic life. See also "Conclusions" section.
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Affiliation(s)
- H Plattner
- Department of Biology, University of Konstanz, P.O. Box 5560, 78457 Konstanz, Germany.
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