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More KJ, Kaur H, Simpson AGB, Spiegel FW, Dacks JB. Contractile vacuoles: a rapidly expanding (and occasionally diminishing?) understanding. Eur J Protistol 2024; 94:126078. [PMID: 38688044 DOI: 10.1016/j.ejop.2024.126078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 03/18/2024] [Accepted: 03/20/2024] [Indexed: 05/02/2024]
Abstract
Osmoregulation is the homeostatic mechanism essential for the survival of organisms in hypoosmotic and hyperosmotic conditions. In freshwater or soil dwelling protists this is frequently achieved through the action of an osmoregulatory organelle, the contractile vacuole. This endomembrane organelle responds to the osmotic challenges and compensates by collecting and expelling the excess water to maintain the cellular osmolarity. As compared with other endomembrane organelles, this organelle is underappreciated and under-studied. Here we review the reported presence or absence of contractile vacuoles across eukaryotic diversity, as well as the observed variability in the structure, function, and molecular machinery of this organelle. Our findings highlight the challenges and opportunities for constructing cellular and evolutionary models for this intriguing organelle.
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Affiliation(s)
- Kiran J More
- Division of Infectious Diseases, Department of Medicine, and Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Harpreet Kaur
- Division of Infectious Diseases, Department of Medicine, and Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Alastair G B Simpson
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, NS, Canada; Department of Biology, Dalhousie University, Halifax, NS, Canada
| | - Frederick W Spiegel
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Joel B Dacks
- Division of Infectious Diseases, Department of Medicine, and Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada; Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic; Centre for Life's Origins and Evolution, Department of Genetics, Evolution, & Environment, University College, London, United Kingdom.
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2
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Velle KB, Garner RM, Beckford TK, Weeda M, Liu C, Kennard AS, Edwards M, Fritz-Laylin LK. A conserved pressure-driven mechanism for regulating cytosolic osmolarity. Curr Biol 2023; 33:3325-3337.e5. [PMID: 37478864 PMCID: PMC10529079 DOI: 10.1016/j.cub.2023.06.061] [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: 03/10/2023] [Revised: 05/24/2023] [Accepted: 06/22/2023] [Indexed: 07/23/2023]
Abstract
Controlling intracellular osmolarity is essential to all cellular life. Cells that live in hypo-osmotic environments, such as freshwater, must constantly battle water influx to avoid swelling until they burst. Many eukaryotic cells use contractile vacuoles to collect excess water from the cytosol and pump it out of the cell. Although contractile vacuoles are essential to many species, including important pathogens, the mechanisms that control their dynamics remain unclear. To identify the basic principles governing contractile vacuole function, we investigate here the molecular mechanisms of two species with distinct vacuolar morphologies from different eukaryotic lineages: the discoban Naegleria gruberi and the amoebozoan slime mold Dictyostelium discoideum. Using quantitative cell biology, we find that although these species respond differently to osmotic challenges, they both use vacuolar-type proton pumps for filling contractile vacuoles and actin for osmoregulation, but not to power water expulsion. We also use analytical modeling to show that cytoplasmic pressure is sufficient to drive water out of contractile vacuoles in these species, similar to findings from the alveolate Paramecium multimicronucleatum. These analyses show that cytoplasmic pressure is sufficient to drive contractile vacuole emptying for a wide range of cellular pressures and vacuolar geometries. Because vacuolar-type proton-pump-dependent contractile vacuole filling and pressure-dependent emptying have now been validated in three eukaryotic lineages that diverged well over a billion years ago, we propose that this represents an ancient eukaryotic mechanism of osmoregulation.
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Affiliation(s)
- Katrina B Velle
- Department of Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Rikki M Garner
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Tatihana K Beckford
- Department of Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Makaela Weeda
- Department of Biology, Amherst College, Amherst, MA 01002, USA
| | - Chunzi Liu
- Department of Applied Mathematics, Harvard University, Cambridge, MA 02138, USA
| | - Andrew S Kennard
- Department of Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Marc Edwards
- Department of Biology, Amherst College, Amherst, MA 01002, USA
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3
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Velle KB, Garner RM, Beckford TK, Weeda M, Liu C, Kennard AS, Edwards M, Fritz-Laylin LK. A conserved pressure-driven mechanism for regulating cytosolic osmolarity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.01.529730. [PMID: 36909496 PMCID: PMC10002747 DOI: 10.1101/2023.03.01.529730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Controlling intracellular osmolarity is essential to all cellular life. Cells that live in hypo-osmotic environments like freshwater must constantly battle water influx to avoid swelling until they burst. Many eukaryotic cells use contractile vacuoles to collect excess water from the cytosol and pump it out of the cell. Although contractile vacuoles are essential to many species, including important pathogens, the mechanisms that control their dynamics remain unclear. To identify basic principles governing contractile vacuole function, we here investigate the molecular mechanisms of two species with distinct vacuolar morphologies from different eukaryotic lineagesâ€"the discoban Naegleria gruberi , and the amoebozoan slime mold Dictyostelium discoideum . Using quantitative cell biology we find that, although these species respond differently to osmotic challenges, they both use actin for osmoregulation, as well as vacuolar-type proton pumps for filling contractile vacuoles. We also use analytical modeling to show that cytoplasmic pressure is sufficient to drive water out of contractile vacuoles in these species, similar to findings from the alveolate Paramecium multimicronucleatum . Because these three lineages diverged well over a billion years ago, we propose that this represents an ancient eukaryotic mechanism of osmoregulation.
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Affiliation(s)
- Katrina B. Velle
- Department of Biology, University of Massachusetts Amherst, Amherst, MA
| | - Rikki M. Garner
- Department of Systems Biology, Harvard Medical School, Boston, MA
| | | | | | - Chunzi Liu
- Department of Applied Mathematics, Harvard University, Cambridge, MA
| | - Andrew S. Kennard
- Department of Biology, University of Massachusetts Amherst, Amherst, MA
| | - Marc Edwards
- Department of Biology, Amherst College, Amherst, MA
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4
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Free-Living Amoebas in Extreme Environments: The True Survival in our Planet. BIOMED RESEARCH INTERNATIONAL 2022; 2022:2359883. [PMID: 36303587 PMCID: PMC9596261 DOI: 10.1155/2022/2359883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 09/08/2022] [Indexed: 12/03/2022]
Abstract
Free-living amoebas (FLAs) are microorganisms, unicellular protozoa widely distributed in nature and present in different environments, such as water or soil; they are maintained in ecosystems and play a fundamental role in the biological control of bacteria, other protozoa, and mushrooms. In particular circumstances, some can reach humans or animals, promoting several health complications. Notably, FLAs are characterized by a robust capacity to survive in extreme environments. However, currently, there is no updated information on the existence and distribution of this protozoan in inhospitable places. Undoubtedly, the cellular physiology of these protozoan microorganisms is very particular. They can resist and live in extreme environments due to their encysting capacity and tolerance to different osmolarities, temperatures, and other environmental factors, which give them excellent adaptative resistance. In this review, we summarized the most relevant evidence related to FLAs and the possible mechanism, which could explain their adaptative capacity to several extreme environments.
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5
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Quintana JF, Field MC. Evolution, function and roles in drug sensitivity of trypanosome aquaglyceroporins. Parasitology 2021; 148:1137-1142. [PMID: 33602349 PMCID: PMC8311954 DOI: 10.1017/s0031182021000354] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/10/2021] [Accepted: 02/15/2021] [Indexed: 12/13/2022]
Abstract
Aquaglyceroporins (AQPs) are membrane proteins that function in osmoregulation and the uptake of low molecular weight solutes, in particular glycerol and urea. The AQP family is highly conserved, with two major subfamilies having arisen very early in prokaryote evolution and retained by eukaryotes. A complex evolutionary history indicates multiple lineage-specific expansions, losses and not uncommonly a complete loss. Consequently, the AQP family is highly evolvable and has been associated with significant events in life on Earth. In the African trypanosomes, a role for the AQP2 paralogue, in sensitivity to two chemotherapeutic agents, pentamidine and melarsoprol, is well established, albeit with the mechanisms for cell entry and resistance unclear until very recently. Here, we discuss AQP evolution, structure and mechanisms by which AQPs impact drug sensitivity, suggesting that AQP2 stability is highly sensitive to mutation while serving as the major uptake pathway for pentamidine.
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Affiliation(s)
- Juan F. Quintana
- Wellcome Centre for Integrative Parasitology (WCIP), Institute of Biodiversity, Animal Health and Comparative Medicine (IBAHCM), University of Glasgow, GlasgowG61 1QH, UK
| | - Mark C. Field
- School of Life Sciences, University of Dundee, DundeeDD1 5EH, UK
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005Ceske Budejovice, Czech Republic
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6
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Ishida M, Hori M, Ooba Y, Kinoshita M, Matsutani T, Naito M, Hagimoto T, Miyazaki K, Ueda S, Miura K, Tominaga T. A Functional Aqp1 Gene Product Localizes on The Contractile Vacuole Complex in Paramecium multimicronucleatum. J Eukaryot Microbiol 2021; 68:e12843. [PMID: 33501744 DOI: 10.1111/jeu.12843] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/17/2020] [Accepted: 12/17/2020] [Indexed: 11/28/2022]
Abstract
In a ciliate Paramecium, the presence of water channels on the membrane of contractile vacuole has long been predicted by both morphological and physiological data, however, to date either the biochemical or the molecular biological data have not been provided. In the present study, to examine the presence of aquaporin in Paramecium, we carried out RT-PCR with degenerated primers designed based on the ParameciumDB, and an aquaporin cDNA (aquaporin 1, aqp1) with a full-length ORF encoding 251 amino acids was obtained from Paramecium multimicronucleatum by using RACE. The deduced amino acid sequence of AQP1 had NPA-NPG motifs, and the prediction of protein secondary structure by CNR5000 and hydropathy plot showed the presence of six putative transmembrane domains and five connecting loops. Phylogenetic analysis results showed that the amino acid sequence of AQP1 was close to that of the Super-aquaporin group. The AQP1-GFP fusion protein clearly demonstrated the subcellular localization of AQP1 on the contractile vacuole complex, except for the decorated spongiome membrane. The functional analyses of aqp1 were done by RNA interference-based gene silencing, using an established feeding method. The aqp1 was found to be crucial for the total fluid output of the cell, the function of contractile vacuole membranes.
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Affiliation(s)
- Masaki Ishida
- School of Science Education, Nara University of Education, Nara, 630-8528, Japan
| | - Manabu Hori
- Department of Biological Science and Chemistry, Faculty of Science, Yamaguchi University, Yamaguchi, Japan
| | - Yui Ooba
- School of Science Education, Nara University of Education, Nara, 630-8528, Japan
| | - Masako Kinoshita
- School of Science Education, Nara University of Education, Nara, 630-8528, Japan
| | - Tsuyoshi Matsutani
- School of Science Education, Nara University of Education, Nara, 630-8528, Japan
| | - Musumi Naito
- School of Science Education, Nara University of Education, Nara, 630-8528, Japan
| | - Taeko Hagimoto
- School of Science Education, Nara University of Education, Nara, 630-8528, Japan
| | - Kuniko Miyazaki
- School of Science Education, Nara University of Education, Nara, 630-8528, Japan
| | - Sou Ueda
- School of Science Education, Nara University of Education, Nara, 630-8528, Japan
| | - Ken Miura
- Laboratory of Applied Entomology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Takashi Tominaga
- Institute of Neuroscience, Tokushima Bunri University, Kagawa, Japan
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Calcino AD, de Oliveira AL, Simakov O, Schwaha T, Zieger E, Wollesen T, Wanninger A. The quagga mussel genome and the evolution of freshwater tolerance. DNA Res 2020; 26:411-422. [PMID: 31504356 PMCID: PMC6796509 DOI: 10.1093/dnares/dsz019] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 08/01/2019] [Indexed: 02/06/2023] Open
Abstract
Freshwater dreissenid mussels evolved from marine ancestors during the Miocene ∼30 million years ago and today include some of the most successful and destructive invasive species of freshwater environments. Here, we sequenced the genome of the quagga mussel Dreissena rostriformis to identify adaptations involved in embryonic osmoregulation. We provide evidence that a lophotrochozoan-specific aquaporin water channel, a vacuolar ATPase subunit and a sodium/hydrogen exchanger are involved in osmoregulation throughout early cleavage, during which time large intercellular fluid-filled 'cleavage cavities' repeatedly form, coalesce and collapse, expelling excess water to the exterior. Independent expansions of aquaporins coinciding with at least five freshwater colonization events confirm their role in freshwater adaptation. Repeated aquaporin expansions and the evolution of membrane-bound fluid-filled osmoregulatory structures in diverse freshwater taxa point to a fundamental principle guiding the evolution of freshwater tolerance and provide a framework for future species control efforts.
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Affiliation(s)
- Andrew D Calcino
- Department of Integrative Zoology, University of Vienna, Vienna, Austria
| | | | - Oleg Simakov
- Department of Molecular Evolution and Development, University of Vienna, Vienna, Austria
| | - Thomas Schwaha
- Department of Integrative Zoology, University of Vienna, Vienna, Austria
| | - Elisabeth Zieger
- Department of Integrative Zoology, University of Vienna, Vienna, Austria
| | - Tim Wollesen
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Andreas Wanninger
- Department of Integrative Zoology, University of Vienna, Vienna, Austria
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Non-periodic oscillatory deformation of an actomyosin microdroplet encapsulated within a lipid interface. Sci Rep 2016; 6:18964. [PMID: 26754862 PMCID: PMC4709586 DOI: 10.1038/srep18964] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 11/30/2015] [Indexed: 11/29/2022] Open
Abstract
Active force generation in living organisms, which is mainly involved in actin cytoskeleton and myosin molecular motors, plays a crucial role in various biological processes. Although the contractile properties of actomyosin have been extensively investigated, their dynamic contribution to a deformable membrane remains unclear because of the cellular complexities and the difficulties associated with in vitro reconstitution. Here, by overcoming these experimental difficulties, we demonstrate the dynamic deformation of a reconstituted lipid interface coupled with self-organized structure of contractile actomyosin. Therein, the lipid interface repeatedly oscillates without any remarkable periods. The oscillatory deformation of the interface is caused by the aster-like three-dimensional hierarchical structure of actomyosin inside the droplet, which is revealed that the oscillation occurs stochastically as a Poisson process.
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9
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Ito H, Nishigami Y, Sonobe S, Ichikawa M. Wrinkling of a spherical lipid interface induced by actomyosin cortex. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:062711. [PMID: 26764731 DOI: 10.1103/physreve.92.062711] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Indexed: 06/05/2023]
Abstract
Actomyosin actively generates contractile forces that provide the plasma membrane with the deformation stresses essential to carry out biological processes. Although the contractile property of purified actomyosin has been extensively studied, to understand the physical contribution of the actomyosin contractile force on a deformable membrane is still a challenging problem and of great interest in the field of biophysics. Here, we reconstitute a model system with a cell-sized deformable interface that exhibits anomalous curvature-dependent wrinkling caused by the actomyosin cortex underneath the spherical closed interface. Through a shape analysis of the wrinkling deformation, we find that the dominant contributor to the wrinkled shape changes from bending elasticity to stretching elasticity of the reconstituted cortex upon increasing the droplet curvature radius of the order of the cell size, i.e., tens of micrometers. The observed curvature dependence is explained by the theoretical description of the cortex elasticity and contractility. Our present results provide a fundamental insight into the deformation of a curved membrane induced by the actomyosin cortex.
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Affiliation(s)
- Hiroaki Ito
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Yukinori Nishigami
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Seiji Sonobe
- Department of Life Science, Graduate School of Life Science, University of Hyogo, Harima Science Park City, Hyogo 678-1297, Japan
| | - Masatoshi Ichikawa
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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Von Bülow J, Beitz E. Number and regulation of protozoan aquaporins reflect environmental complexity. THE BIOLOGICAL BULLETIN 2015; 229:38-46. [PMID: 26338868 DOI: 10.1086/bblv229n1p38] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Protozoa are a diverse group of unicellular eukaryotes. Evidence has accumulated that protozoan aquaporin water and solute channels (AQP) contribute to adaptation in changing environments. Intracellular protozoan parasites live a well-sheltered life. Plasmodium spp. express a single AQP, Toxoplasma gondii two, while Trypanosoma cruzi and Leishamnia spp. encode up to five AQPs. Their AQPs are thought to import metabolic precursors and simultaneously to dispose of waste and to help parasites survive osmotic stress during transmission to and from the insect vector or during kidney passages. Trypanosoma brucei is a protozoan parasite that swims freely in the human blood. Expression and intracellular localization of the three T. brucei AQPs depend on the stage of differentiation during the life cycle, suggesting distinct roles in energy generation, metabolism, and cell motility. Free-living amoebae are in direct contact with the environment, encountering severe and sudden changes in the availability of nutrition, and in the osmotic conditions due to rainfall or drought. Amoeba proteus expresses a single AQP that is present in the contractile vacuole complex required for osmoregulation, whereas Dictyostelium discoideum expresses four AQPs, of which two are present in the single-celled amoeboidal stage and two more in the later multicellular stages preceding spore formation. The number and regulation of protozoan aquaporins may reflect environmental complexity. We highlight the gated AqpB from D. discoideum as an example of how life in the wild is challenged by a complex AQP structure-function relationship.
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Affiliation(s)
- Julia Von Bülow
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76, 24118 Kiel, Germany
| | - Eric Beitz
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76, 24118 Kiel, Germany
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11
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von Bülow J, Golldack A, Albers T, Beitz E. The amoeboidalDictyosteliumaquaporin AqpB is gated via Tyr216 andaqpBgene deletion affects random cell motility. Biol Cell 2015; 107:78-88. [DOI: 10.1111/boc.201400070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 12/22/2014] [Indexed: 02/03/2023]
Affiliation(s)
- Julia von Bülow
- Pharmaceutical and Medicinal Chemistry; Christian-Albrechts-University of Kiel; Kiel 24118 Germany
| | - André Golldack
- Pharmaceutical and Medicinal Chemistry; Christian-Albrechts-University of Kiel; Kiel 24118 Germany
| | - Tineke Albers
- Pharmaceutical and Medicinal Chemistry; Christian-Albrechts-University of Kiel; Kiel 24118 Germany
| | - Eric Beitz
- Pharmaceutical and Medicinal Chemistry; Christian-Albrechts-University of Kiel; Kiel 24118 Germany
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12
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Raven JA, Doblin MA. Active water transport in unicellular algae: where, why, and how. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:6279-6292. [PMID: 25205578 DOI: 10.1093/jxb/eru360] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The occurrence of active water transport (net transport against a free energy gradient) in photosynthetic organisms has been debated for several decades. Here, active water transport is considered in terms of its roles, where it is found, and the mechanisms by which it could occur. First there is a brief consideration of the possibility of active water transport into plant xylem in the generation of root pressure and the refilling of embolized xylem elements, and from an unsaturated atmosphere into terrestrial organisms living in habitats with limited availability of liquid water. There is then a more detailed consideration of volume and osmotic regulation in wall-less freshwater unicells, and the possibility of generation of buoyancy in marine phytoplankton such as large-celled diatoms. Calculations show that active water transport is a plausible mechanism to assist cells in upwards vertical movements, requires less energy than synthesis of low-density organic solutes, and potentially on a par with excluding certain ions from the vacuole.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK School of Plant Biology, University of Western Australia, M048, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Martina A Doblin
- Plant Functional Biology and Climate Change Cluster (C3), University of Technology Sydney, PO Box 123, NSW 2007, Australia
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Komsic-Buchmann K, Wöstehoff L, Becker B. The contractile vacuole as a key regulator of cellular water flow in Chlamydomonas reinhardtii. EUKARYOTIC CELL 2014; 13:1421-30. [PMID: 25217463 PMCID: PMC4248701 DOI: 10.1128/ec.00163-14] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 09/08/2014] [Indexed: 01/29/2023]
Abstract
Most freshwater flagellates use contractile vacuoles (CVs) to expel excess water. We have used Chlamydomonas reinhardtii as a green model system to investigate CV function during adaptation to osmotic changes in culture medium. We show that the contractile vacuole in Chlamydomonas is regulated in two different ways. The size of the contractile vacuoles increases during cell growth, with the contraction interval strongly depending on the osmotic strength of the medium. In contrast, there are only small fluctuations in cytosolic osmolarity and plasma membrane permeability. Modeling of the CV membrane permeability indicates that only a small osmotic gradient is necessary for water flux into the CV, which most likely is facilitated by the aquaporin major intrinsic protein 1 (MIP1). We show that MIP1 is localized to the contractile vacuole, and that the expression rate and protein level of MIP1 exhibit only minor fluctuations under different osmotic conditions. In contrast, SEC6, a protein of the exocyst complex that is required for the water expulsion step, and a dynamin-like protein are upregulated under strong hypotonic conditions. The overexpression of a CreMIP1-GFP construct did not change the physiology of the CV. The functional implications of these results are discussed.
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14
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Niyogi S, Mucci J, Campetella O, Docampo R. Rab11 regulates trafficking of trans-sialidase to the plasma membrane through the contractile vacuole complex of Trypanosoma cruzi. PLoS Pathog 2014; 10:e1004224. [PMID: 24968013 PMCID: PMC4072791 DOI: 10.1371/journal.ppat.1004224] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 05/19/2014] [Indexed: 01/09/2023] Open
Abstract
Trypanosoma cruzi is the etiologic agent of Chagas disease. Although this is not a free-living organism it has conserved a contractile vacuole complex (CVC) to regulate its osmolarity. This obligate intracellular pathogen is, in addition, dependent on surface proteins to invade its hosts. Here we used a combination of genetic and biochemical approaches to delineate the contribution of the CVC to the traffic of glycosylphosphatidylinositol (GPI)-anchored proteins to the plasma membrane of the parasite and promote host invasion. While T. cruzi Rab11 (GFP-TcRab11) localized to the CVC, a dominant negative (DN) mutant tagged with GFP (GFP-TcRab11DN) localized to the cytosol, and epimastigotes expressing this mutant were less responsive to hyposmotic and hyperosmotic stress. Mutant parasites were still able to differentiate into metacyclic forms and infect host cells. GPI-anchored trans-sialidase (TcTS), mucins of the 60-200 KDa family, and trypomastigote small surface antigen (TcTSSA II) co-localized with GFP-TcRab11 to the CVC during transformation of intracellular amastigotes into trypomastigotes. Mucins of the gp35/50 family also co-localized with the CVC during metacyclogenesis. Parasites expressing GFP-TcRab11DN prevented TcTS, but not other membrane proteins, from reaching the plasma membrane, and were less infective as compared to wild type cells. Incubation of these mutants in the presence of exogenous recombinant active, but not inactive, TcTS, and a sialic acid donor, before infecting host cells, partially rescued infectivity of trypomastigotes. Taking together these results reveal roles of TcRab11 in osmoregulation and trafficking of trans-sialidase to the plasma membrane, the role of trans-sialidase in promoting infection, and a novel unconventional mechanism of GPI-anchored protein secretion.
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Affiliation(s)
- Sayantanee Niyogi
- Department of Cellular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Juan Mucci
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín/Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Oscar Campetella
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín/Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Roberto Docampo
- Department of Cellular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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15
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Parasite aquaporins: Current developments in drug facilitation and resistance. Biochim Biophys Acta Gen Subj 2014; 1840:1566-73. [DOI: 10.1016/j.bbagen.2013.10.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 10/02/2013] [Accepted: 10/06/2013] [Indexed: 01/15/2023]
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Larsen EH, Deaton LE, Onken H, O'Donnell M, Grosell M, Dantzler WH, Weihrauch D. Osmoregulation and Excretion. Compr Physiol 2014; 4:405-573. [DOI: 10.1002/cphy.c130004] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Farlora R, Araya-Garay J, Gallardo-Escárate C. Discovery of sex-related genes through high-throughput transcriptome sequencing from the salmon louse Caligus rogercresseyi. Mar Genomics 2014; 15:85-93. [PMID: 24642131 DOI: 10.1016/j.margen.2014.02.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 02/24/2014] [Accepted: 02/25/2014] [Indexed: 01/16/2023]
Abstract
Understanding the molecular underpinnings involved in the reproduction of the salmon louse is critical for designing novel strategies of pest management for this ectoparasite. However, genomic information on sex-related genes is still limited. In the present work, sex-specific gene transcription was revealed in the salmon louse Caligus rogercresseyi using high-throughput Illumina sequencing. A total of 30,191,914 and 32,292,250 high quality reads were generated for females and males, and these were de novo assembled into 32,173 and 38,177 contigs, respectively. Gene ontology analysis showed a pattern of higher expression in the female as compared to the male transcriptome. Based on our sequence analysis and known sex-related proteins, several genes putatively involved in sex differentiation, including Dmrt3, FOXL2, VASA, and FEM1, and other potentially significant candidate genes in C. rogercresseyi, were identified for the first time. In addition, the occurrence of SNPs in several differentially expressed contigs annotating for sex-related genes was found. This transcriptome dataset provides a useful resource for future functional analyses, opening new opportunities for sea lice pest control.
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Affiliation(s)
- Rodolfo Farlora
- Laboratory of Biotechnology and Aquatic Genomics, Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, P.O. Box 160-C, Chile
| | - José Araya-Garay
- Laboratory of Biotechnology and Aquatic Genomics, Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, P.O. Box 160-C, Chile
| | - Cristian Gallardo-Escárate
- Laboratory of Biotechnology and Aquatic Genomics, Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, P.O. Box 160-C, Chile.
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Staniscuaski F, Paluzzi JP, Real-Guerra R, Carlini CR, Orchard I. Expression analysis and molecular characterization of aquaporins in Rhodnius prolixus. JOURNAL OF INSECT PHYSIOLOGY 2013; 59:1140-1150. [PMID: 24035749 DOI: 10.1016/j.jinsphys.2013.08.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 08/28/2013] [Accepted: 08/30/2013] [Indexed: 06/02/2023]
Abstract
Aquaporins (AQPs) are water channels responsible for transport of water and, in some cases, transport of small solutes such as urea and glycerol across lipid bilayer membranes. Hematophagous insects, such as Rhodnius prolixus, ingest large volumes of fluid and must rapidly eliminate the excess of water and salts from the blood meal within the gut. In order to deal with this increase in body fluid volume, a hormone-controlled diuresis is activated, during which a high rate of water and salt absorption occurs across the anterior midgut, followed by secretion of water and salts by the Malpighian tubules (MTs). Previously, one member of the MIP family (major intrinsic protein that includes the AQP family) was identified in the MTs of R. prolixus, and named RpMIP. We have described here that the RpMIP gene has different variants, and is present in tissues other than MTs. In addition, we have characterized a new AQP (RhoprAQP1) found in different tissues of R. prolixus. The expression of these transcripts in unfed insects as well as blood fed insects was evaluated using real-time quantitative PCR. Molecular models of the predicted proteins were constructed and the characteristics of their pores evaluated. A yeast complementation assay was used to validate that the products of these transcripts were bona fide AQPs. Both RhoprAQP1 and RhoprMIP-A were capable of transporting water whereas RhoprMIP-A was also capable of transporting H2O2. Taken together, these analyses suggest that RhoprMIP is probably an aquaglyceroporin, while RhoprAQP1 appears to be a strict aquaporin that transports only water.
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Affiliation(s)
- Fernanda Staniscuaski
- Department of Molecular Biology and Biotechnology, Institute of Biosciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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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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Nishigami Y, Ichikawa M, Kazama T, Kobayashi R, Shimmen T, Yoshikawa K, Sonobe S. Reconstruction of active regular motion in amoeba extract: dynamic cooperation between sol and gel states. PLoS One 2013; 8:e70317. [PMID: 23940560 PMCID: PMC3734023 DOI: 10.1371/journal.pone.0070317] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 06/17/2013] [Indexed: 11/18/2022] Open
Abstract
Amoeboid locomotion is one of the typical modes of biological cell migration. Cytoplasmic sol–gel conversion of an actomyosin system is thought to play an important role in locomotion. However, the mechanisms underlying sol–gel conversion, including trigger, signal, and regulating factors, remain unclear. We developed a novel model system in which an actomyosin fraction moves like an amoeba in a cytoplasmic extract. Rheological study of this model system revealed that the actomyosin fraction exhibits shear banding: the sol–gel state of actomyosin can be regulated by shear rate or mechanical force. Furthermore, study of the living cell indicated that the shear-banding property also causes sol–gel conversion with the same order of magnitude as that of shear rate. Our results suggest that the inherent sol–gel transition property plays an essential role in the self-regulation of autonomous translational motion in amoeba.
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Affiliation(s)
- Yukinori Nishigami
- Department of Life Science, Graduate School of Life Science, University of Hyogo, Harima Science Park City, Hyogo, Japan
| | - Masatoshi Ichikawa
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, Japan
- * E-mail: (MI); (SS)
| | - Toshiya Kazama
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Japan
| | - Ryo Kobayashi
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Japan
| | - Teruo Shimmen
- Department of Life Science, Graduate School of Life Science, University of Hyogo, Harima Science Park City, Hyogo, Japan
| | - Kenichi Yoshikawa
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, Japan
- Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Seiji Sonobe
- Department of Life Science, Graduate School of Life Science, University of Hyogo, Harima Science Park City, Hyogo, Japan
- * E-mail: (MI); (SS)
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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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New insights into roles of acidocalcisomes and contractile vacuole complex in osmoregulation in protists. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 305:69-113. [PMID: 23890380 DOI: 10.1016/b978-0-12-407695-2.00002-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
While free-living protists are usually subjected to hyposmotic environments, parasitic protists are also in contact with hyperosmotic habitats. Recent work in one of these parasites, Trypanosoma cruzi, has revealed that its contractile vacuole complex, which usually collects and expels excess water as a mechanism of regulatory volume decrease after hyposmotic stress, has also a role in cell shrinking when the cells are submitted to hyperosmotic stress. Trypanosomes also have an acidic calcium store rich in polyphosphate (polyP), named the acidocalcisome, which is involved in their response to osmotic stress. Here, we review newly emerging insights on the role of acidocalcisomes and the contractile vacuole complex in the cellular response to hyposmotic and hyperosmotic stresses. We also review the current state of knowledge on the composition of these organelles and their other roles in calcium homeostasis and protein trafficking.
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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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Komsic-Buchmann K, Stephan LM, Becker B. The SEC6 protein is required for contractile vacuole function in Chlamydomonas reinhardtii. J Cell Sci 2012; 125:2885-95. [PMID: 22427688 DOI: 10.1242/jcs.099184] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Contractile vacuoles (CVs) are essential for osmoregulation in many protists. To investigate the mechanism of CV function in Chlamydomonas, we isolated novel osmoregulatory mutants. Four of the isolated mutant cell lines carried the same 33,641 base deletion, rendering the cell lines unable to grow under strong hypotonic conditions. One mutant cell line (Osmo75) was analyzed in detail. The CV morphology was variable in mutant cells, and most cells had multiple small CVs. In addition, one or two enlarged CVs or no visible CVs at all, were observed by light microscopy. These findings suggest that the mutant is impaired in homotypic vacuolar and exocytotic membrane fusion. Furthermore the mutants had long flagella. One of the affected genes is the only SEC6 homologue in Chlamydomonas (CreSEC6). The SEC6 protein is a component of the exocyst complex that is required for efficient exocytosis. Transformation of the Osmo75 mutant with a CreSEC6-GFP construct rescued the mutant completely (osmoregulation and flagellar length). Rescued strains overexpressed CreSEC6 (as a GFP-tagged protein) and displayed a modified CV activity. CVs were larger, whereas the CV contraction interval remained unchanged, leading to increased water efflux rates. Electron microscopy analysis of Osmo75 cells showed that the mutant is able to form the close contact zones between the plasma membrane and the CV membrane observed during late diastole and systole. These results indicate that CreSEC6 is essential for CV function and required for homotypic vesicle fusion during diastole and water expulsion during systole. In addition, CreSEC6 is not only necessary for CV function, but possibly influences the CV cycle in an indirect manner and flagellar length in Chlamydomonas.
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von Bülow J, Müller-Lucks A, Kai L, Bernhard F, Beitz E. Functional characterization of a novel aquaporin from Dictyostelium discoideum amoebae implies a unique gating mechanism. J Biol Chem 2012; 287:7487-94. [PMID: 22262860 DOI: 10.1074/jbc.m111.329102] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The social amoeba Dictyostelium discoideum is a widely used model organism for studying basic functions of protozoan and metazoan cells, such as osmoregulation and cell motility. There is evidence from other species that cellular water channels, aquaporins (AQP), are central to both processes. Yet, data on D. discoideum AQPs is almost absent. Despite cloning of two putative D. discoideum AQPs, WacA, and AqpA, water permeability has not been shown. Further, WacA and AqpA are expressed at the late multicellular stage and in spores but not in amoebae. We cloned a novel AQP, AqpB, from amoeboidal D. discoideum cells. Wild-type AqpB was impermeable to water, glycerol, and urea when expressed in Xenopus laevis oocytes. Neither stepwise truncation of the N terminus nor selected point mutations activated the water channel. However, mutational truncation by 12 amino acids of an extraordinary long intracellular loop induced water permeability of AqpB, hinting at a novel gating mechanism. This AqpB mutant was inhibited by mercuric chloride, confirming the presence of a cysteine residue in the selectivity filter as predicted by our structure model. We detected AqpB by Western blot analysis in a glycosylated and a non-glycosylated form throughout all developmental stages. When expressed in D. discoideum amoebae, AqpB-GFP fusion constructs localized to vacuolar structures, to the plasma membrane, and to lamellipodia-like membrane protrusions. We conclude that the localization pattern in conjunction with channel gating may be indicative of AqpB functions in osmoregulation as well as cell motility of D. discoideum.
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Affiliation(s)
- Julia von Bülow
- Department of Medicinal and Pharmaceutical Chemistry, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
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26
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Ulrich PN, Jimenez V, Park M, Martins VP, Atwood J, Moles K, Collins D, Rohloff P, Tarleton R, Moreno SNJ, Orlando R, Docampo R. Identification of contractile vacuole proteins in Trypanosoma cruzi. PLoS One 2011; 6:e18013. [PMID: 21437209 PMCID: PMC3060929 DOI: 10.1371/journal.pone.0018013] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Accepted: 02/22/2011] [Indexed: 11/19/2022] Open
Abstract
Contractile vacuole complexes are critical components of cell volume regulation
and have been shown to have other functional roles in several free-living
protists. However, very little is known about the functions of the contractile
vacuole complex of the parasite Trypanosoma cruzi, the
etiologic agent of Chagas disease, other than a role in osmoregulation.
Identification of the protein composition of these organelles is important for
understanding their physiological roles. We applied a combined proteomic and
bioinfomatic approach to identify proteins localized to the contractile vacuole.
Proteomic analysis of a T. cruzi fraction enriched for
contractile vacuoles and analyzed by one-dimensional gel electrophoresis and
LC-MS/MS resulted in the addition of 109 newly detected proteins to the group of
expressed proteins of epimastigotes. We also identified different peptides that
map to at least 39 members of the dispersed gene family 1 (DGF-1) providing
evidence that many members of this family are simultaneously expressed in
epimastigotes. Of the proteins present in the fraction we selected several
homologues with known localizations in contractile vacuoles of other organisms
and others that we expected to be present in these vacuoles on the basis of
their potential roles. We determined the localization of each by expression as
GFP-fusion proteins or with specific antibodies. Six of these putative proteins
(Rab11, Rab32, AP180, ATPase subunit B, VAMP1, and phosphate transporter)
predominantly localized to the vacuole bladder. TcSNARE2.1, TcSNARE2.2, and
calmodulin localized to the spongiome. Calmodulin was also cytosolic. Our
results demonstrate the utility of combining subcellular fractionation,
proteomic analysis, and bioinformatic approaches for localization of organellar
proteins that are difficult to detect with whole cell methodologies. The CV
localization of the proteins investigated revealed potential novel roles of
these organelles in phosphate metabolism and provided information on the
potential participation of adaptor protein complexes in their biogenesis.
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Affiliation(s)
- Paul N. Ulrich
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - Veronica Jimenez
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - Miyoung Park
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - Vicente P. Martins
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - James Atwood
- Complex Carbohydrate Research Center,
University of Georgia, Athens, Georgia, United States of America
| | - Kristen Moles
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - Dalis Collins
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - Peter Rohloff
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - Rick Tarleton
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - Silvia N. J. Moreno
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - Ron Orlando
- Complex Carbohydrate Research Center,
University of Georgia, Athens, Georgia, United States of America
| | - Roberto Docampo
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
- * E-mail:
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Drake LL, Boudko DY, Marinotti O, Carpenter VK, Dawe AL, Hansen IA. The Aquaporin gene family of the yellow fever mosquito, Aedes aegypti. PLoS One 2010; 5:e15578. [PMID: 21249121 PMCID: PMC3014591 DOI: 10.1371/journal.pone.0015578] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 11/17/2010] [Indexed: 11/18/2022] Open
Abstract
Background The mosquito, Aedes aegypti, is the principal vector of the Dengue and yellow fever viruses. During feeding, an adult female can take up more than its own body weight in vertebrate blood. After a blood meal females excrete large amounts of urine through their excretion system, the Malpighian tubules (MT). Diuresis starts within seconds after the mosquito starts feeding. Aquaporins (AQPs) are a family of membrane transporters that regulate the flow of water, glycerol and other small molecules across cellular membranes in both prokaryotic and eukaryotic cells. Our aim was to identify aquaporins that function as water channels, mediating transcellular water transport in MTs of adult female Ae. aegypti. Methodology/Principal Findings Using a bioinformatics approach we screened genome databases and identified six putative AQPs in the genome of Ae. aegypti. Phylogenetic analysis showed that five of the six Ae. aegypti AQPs have high similarity to classical water-transporting AQPs of vertebrates. Using microarray, reverse transcription and real time PCR analysis we found that all six AQPs are expressed in distinct patterns in mosquito tissues/body parts. AaAQP1, 4, and 5 are strongly expressed in the adult female MT. RNAi-mediated knockdown of the MT-expressed mosquito AQPs resulted in significantly reduced diuresis. Conclusions/Significance Our results support the notion that AQP1, 4, and 5 function as water transporters in the MTs of adult female Ae. aegypti mosquitoes. Our results demonstrate the importance of these AQPs for mosquito diuresis after blood ingestion and highlight their potential as targets for the development of novel vector control strategies.
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Affiliation(s)
- Lisa L. Drake
- Department of Biology, New Mexico State University, Las Cruces, New Mexico, United States of America
| | - Dmitri Y. Boudko
- Chicago Medical School, Rosalind Franklin University, North Chicago, Illinois, United States of America
| | - Osvaldo Marinotti
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California, United States of America
| | - Victoria K. Carpenter
- Department of Biology, New Mexico State University, Las Cruces, New Mexico, United States of America
| | - Angus L. Dawe
- Department of Biology, New Mexico State University, Las Cruces, New Mexico, United States of America
- Molecular Biology Program, New Mexico State University, Las Cruces, New Mexico, United States of America
| | - Immo A. Hansen
- Department of Biology, New Mexico State University, Las Cruces, New Mexico, United States of America
- Institute of Applied Biosciences, New Mexico State University, Las Cruces, New Mexico, United States of America
- Molecular Biology Program, New Mexico State University, Las Cruces, New Mexico, United States of America
- * E-mail:
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Betapudi V, Egelhoff TT. Roles of an unconventional protein kinase and myosin II in amoeba osmotic shock responses. Traffic 2009; 10:1773-84. [PMID: 19843280 DOI: 10.1111/j.1600-0854.2009.00992.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The contractile vacuole (CV) is a dynamic organelle that enables Dictyostelium amoeba and other protist to maintain osmotic homeostasis by expelling excess water. In the present study, we have uncovered a mechanism that coordinates the mechanics of the CV with myosin II, regulated by VwkA, an unconventional protein kinase that is conserved in an array of protozoa. Green fluorescent protein (GFP)-VwkA fusion proteins localize persistently to the CV during both filling and expulsion phases of water. In vwkA null cells, the established CV marker dajumin still localizes to the CV, but these structures are large, spherical and severely impaired for discharge. Furthermore, myosin II cortical localization and assembly are abnormal in vwkA null cells. Parallel analysis of wild-type cells treated with myosin II inhibitors or of myosin II null cells also results in enlarged CVs with impaired dynamics. We suggest that the myosin II cortical cytoskeleton, regulated by VwkA, serves a critical conserved role in the periodic contractions of the CV, as part of the osmotic protective mechanism of protozoa.
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Affiliation(s)
- Venkaiah Betapudi
- Department of Cell Biology, The Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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Benga G. Water channel proteins (later called aquaporins) and relatives: past, present, and future. IUBMB Life 2009; 61:112-33. [PMID: 19165894 DOI: 10.1002/iub.156] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Water channels or water channel proteins (WCPs) are transmembrane proteins that have a specific three-dimensional structure with a pore that can be permeated by water molecules. WCPs are large families (over 450 members) that are present in all kingdoms of life. The first WCP was discovered in the human red blood cell (RBC) membrane in 1980s. In 1990s other WCPs were discovered in plants, microorganisms, various animals, and humans; and it became obvious that the WCPs belong to the superfamily of major intrinsic proteins (MIPs, over 800 members). WCPs include three subfamilies: (a) aquaporins (AQPs), which are water specific (or selective water channels); (b) aquaglyceroporins (and glycerol facilitators), which are permeable to water and/or other small molecules; and (c) "superaquaporins" or subcellular AQPs. WCPs (and MIPs) have several structural characteristics which were better understood after the atomic structure of some MIPs was deciphered. The structure-function relationships of MIPs expressed in microorganisms (bacteria, archaea, yeast, and protozoa), plants, and some multicellular animal species [nematodes, insects, fishes, amphibians, mammals (and humans)] are described. A synthetic overview on the WCPs from RBCs from various species is provided. The physiological roles of WCPs in kidney, gastrointestinal system, respiratory apparatus, central nervous system, eye, adipose tissue, skin are described, and some implications of WCPs in various diseases are briefly presented. References of detailed reviews on each topic are given. This is the first review providing in a condensed form an overview of the whole WCP field that became in the last 20 years a very hot area of research in biochemistry and molecular cell biology, with wide and increasing implications.
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Affiliation(s)
- Gheorghe Benga
- Department of Cell and Molecular Biology, Iuliu HaTieganu University of Medicine and Pharmacy Cluj-Napoca, Cluj-Napoca, Romania.
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30
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Invertebrate aquaporins: a review. J Comp Physiol B 2008; 178:935-55. [DOI: 10.1007/s00360-008-0288-2] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Revised: 06/03/2008] [Accepted: 06/10/2008] [Indexed: 10/25/2022]
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