1
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Bindschedler A, Schmuckli-Maurer J, Buchser S, Fischer TD, Wacker R, Davalan T, Brunner J, Heussler VT. LC3B labeling of the parasitophorous vacuole membrane of Plasmodium berghei liver stage parasites depends on the V-ATPase and ATG16L1. Mol Microbiol 2024. [PMID: 38574236 DOI: 10.1111/mmi.15259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 03/11/2024] [Accepted: 03/14/2024] [Indexed: 04/06/2024]
Abstract
The protozoan parasite Plasmodium, the causative agent of malaria, undergoes an obligatory stage of intra-hepatic development before initiating a blood-stage infection. Productive invasion of hepatocytes involves the formation of a parasitophorous vacuole (PV) generated by the invagination of the host cell plasma membrane. Surrounded by the PV membrane (PVM), the parasite undergoes extensive replication. During intracellular development in the hepatocyte, the parasites provoke the Plasmodium-associated autophagy-related (PAAR) response. This is characterized by a long-lasting association of the autophagy marker protein, and ATG8 family member, LC3B with the PVM. LC3B localization at the PVM does not follow the canonical autophagy pathway since upstream events specific to canonical autophagy are dispensable. Here, we describe that LC3B localization at the PVM of Plasmodium parasites requires the V-ATPase and its interaction with ATG16L1. The WD40 domain of ATG16L1 is crucial for its recruitment to the PVM. Thus, we provide new mechanistic insight into the previously described PAAR response targeting Plasmodium liver stage parasites.
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Affiliation(s)
- Annina Bindschedler
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | | | - Sophie Buchser
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Tara D Fischer
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Rahel Wacker
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Tim Davalan
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Jessica Brunner
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Volker T Heussler
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
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2
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Romano PS, Akematsu T, Besteiro S, Bindschedler A, Carruthers VB, Chahine Z, Coppens I, Descoteaux A, Alberto Duque TL, He CY, Heussler V, Le Roch KG, Li FJ, de Menezes JPB, Menna-Barreto RFS, Mottram JC, Schmuckli-Maurer J, Turk B, Tavares Veras PS, Salassa BN, Vanrell MC. Autophagy in protists and their hosts: When, how and why? Autophagy Rep 2023; 2:2149211. [PMID: 37064813 PMCID: PMC10104450 DOI: 10.1080/27694127.2022.2149211] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 11/15/2022] [Indexed: 03/12/2023]
Abstract
Pathogenic protists are a group of organisms responsible for causing a variety of human diseases including malaria, sleeping sickness, Chagas disease, leishmaniasis, and toxoplasmosis, among others. These diseases, which affect more than one billion people globally, mainly the poorest populations, are characterized by severe chronic stages and the lack of effective antiparasitic treatment. Parasitic protists display complex life-cycles and go through different cellular transformations in order to adapt to the different hosts they live in. Autophagy, a highly conserved cellular degradation process, has emerged as a key mechanism required for these differentiation processes, as well as other functions that are crucial to parasite fitness. In contrast to yeasts and mammals, protist autophagy is characterized by a modest number of conserved autophagy-related proteins (ATGs) that, even though, can drive the autophagosome formation and degradation. In addition, during their intracellular cycle, the interaction of these pathogens with the host autophagy system plays a crucial role resulting in a beneficial or harmful effect that is important for the outcome of the infection. In this review, we summarize the current state of knowledge on autophagy and other related mechanisms in pathogenic protists and their hosts. We sought to emphasize when, how, and why this process takes place, and the effects it may have on the parasitic cycle. A better understanding of the significance of autophagy for the protist life-cycle will potentially be helpful to design novel anti-parasitic strategies.
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Affiliation(s)
- Patricia Silvia Romano
- Laboratorio de Biología de Trypanosoma cruzi y de la célula hospedadora. Instituto de Histología y Embriología de Mendoza. Universidad Nacional de Cuyo. (IHEM-CONICET-UNCUYO). Facultad de Ciencias Médicas. Universidad Nacional de Cuyo. Av. Libertador 80 (5500), Mendoza, Argentina
| | - Takahiko Akematsu
- Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo, Japan
| | | | | | - Vern B Carruthers
- Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, MI, USA
| | - Zeinab Chahine
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology. Department of Molecular Microbiology and Immunology. Johns Hopkins Malaria Research Institute. Johns Hopkins University Bloomberg School of Public Health. Baltimore 21205, MD, USA
| | - Albert Descoteaux
- Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique, Laval, QC
| | - Thabata Lopes Alberto Duque
- Autophagy Inflammation and Metabolism Center, University of New Mexico Health Sciences Center, Albuquerque, NM, USA; Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Cynthia Y He
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Volker Heussler
- Institute of Cell Biology.University of Bern. Baltzerstr. 4 3012 Bern
| | - Karine G Le Roch
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA
| | - Feng-Jun Li
- Department of Biological Sciences, National University of Singapore, Singapore
| | | | | | - Jeremy C Mottram
- York Biomedical Research Institute, Department of Biology, University of York, York, UK
| | | | - Boris Turk
- Department of Biochemistry and Molecular and Structural Biology, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Patricia Sampaio Tavares Veras
- Laboratory of Host-Parasite Interaction and Epidemiology, Gonçalo Moniz Institute, Fiocruz-Bahia
- National Institute of Science and Technology of Tropical Diseases - National Council for Scientific Research and Development (CNPq)
| | - Betiana Nebai Salassa
- Laboratorio de Biología de Trypanosoma cruzi y de la célula hospedadora. Instituto de Histología y Embriología de Mendoza. Universidad Nacional de Cuyo. (IHEM-CONICET-UNCUYO). Facultad de Ciencias Médicas. Universidad Nacional de Cuyo. Av. Libertador 80 (5500), Mendoza, Argentina
| | - María Cristina Vanrell
- Laboratorio de Biología de Trypanosoma cruzi y de la célula hospedadora. Instituto de Histología y Embriología de Mendoza. Universidad Nacional de Cuyo. (IHEM-CONICET-UNCUYO). Facultad de Ciencias Médicas. Universidad Nacional de Cuyo. Av. Libertador 80 (5500), Mendoza, Argentina
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3
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Bindschedler A, Wacker R, Egli J, Eickel N, Schmuckli-Maurer J, Franke-Fayard BM, Janse CJ, Heussler VT. Plasmodium berghei sporozoites in nonreplicative vacuole are eliminated by a PI3P-mediated autophagy-independent pathway. Cell Microbiol 2020; 23:e13271. [PMID: 32979009 PMCID: PMC7757174 DOI: 10.1111/cmi.13271] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/01/2022]
Abstract
The protozoan parasite Plasmodium, causative agent of malaria, invades hepatocytes by invaginating the host cell plasma membrane and forming a parasitophorous vacuole membrane (PVM). Surrounded by this PVM, the parasite undergoes extensive replication. Parasites inside a PVM provoke the Plasmodium‐associated autophagy‐related (PAAR) response. This is characterised by a long‐lasting association of the autophagy marker protein LC3 with the PVM, which is not preceded by phosphatidylinositol 3‐phosphate (PI3P)‐labelling. Prior to productive invasion, sporozoites transmigrate several cells and here we describe that a proportion of traversing sporozoites become trapped in a transient traversal vacuole, provoking a host cell response that clearly differs from the PAAR response. These trapped sporozoites provoke PI3P‐labelling of the surrounding vacuolar membrane immediately after cell entry, followed by transient LC3‐labelling and elimination of the parasite by lysosomal acidification. Our data suggest that this PI3P response is not only restricted to sporozoites trapped during transmigration but also affects invaded parasites residing in a compromised vacuole. Thus, host cells can employ a pathway distinct from the previously described PAAR response to efficiently recognise and eliminate Plasmodium parasites.
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Affiliation(s)
- Annina Bindschedler
- Institute of Cell Biology, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Rahel Wacker
- Institute of Cell Biology, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Jessica Egli
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Nina Eickel
- Institute of Cell Biology, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | | | - Blandine M Franke-Fayard
- Leiden malaria group, Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Chris J Janse
- Leiden malaria group, Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
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4
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Niklaus L, Agop-Nersesian C, Schmuckli-Maurer J, Wacker R, Grünig V, Heussler VT. Deciphering host lysosome-mediated elimination of Plasmodium berghei liver stage parasites. Sci Rep 2019; 9:7967. [PMID: 31138850 PMCID: PMC6538699 DOI: 10.1038/s41598-019-44449-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 05/13/2019] [Indexed: 02/08/2023] Open
Abstract
Liver stage Plasmodium parasites reside in a parasitophorous vacuole (PV) that associates with lysosomes. It has previously been shown that these organelles can have beneficial as well as harmful effects on the parasite. Yet it is not clear how the association of lysosomes with the parasite is controlled and how interactions with these organelles lead to the antagonistic outcomes. In this study we used advanced imaging techniques to characterize lysosomal interactions with the PV. In host cells harboring successfully developing parasites we observed that these interaction events reach an equilibrium at the PV membrane (PVM). In a population of arrested parasites, this equilibrium appeared to shift towards a strongly increased lysosomal fusion with the PVM witnessed by strong PVM labeling with the lysosomal marker protein LAMP1. This was followed by acidification of the PV and elimination of the parasite. To systematically investigate elimination of arrested parasites, we generated transgenic parasites that express the photosensitizer KillerRed, which leads to parasite killing after activation. Our work provides insights in cellular details of intracellular killing and lysosomal elimination of Plasmodium parasites independent of cells of the immune system.
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Affiliation(s)
- L Niklaus
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- Graduate School of Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - C Agop-Nersesian
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, MA, USA
| | | | - R Wacker
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - V Grünig
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - V T Heussler
- Institute of Cell Biology, University of Bern, Bern, Switzerland.
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5
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Wacker R, Eickel N, Schmuckli-Maurer J, Annoura T, Niklaus L, Khan SM, Guan JL, Heussler VT. LC3-association with the parasitophorous vacuole membrane of Plasmodium berghei liver stages follows a noncanonical autophagy pathway. Cell Microbiol 2017; 19. [PMID: 28573684 DOI: 10.1111/cmi.12754] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 05/23/2017] [Accepted: 05/31/2017] [Indexed: 12/22/2022]
Abstract
Eukaryotic cells can employ autophagy to defend themselves against invading pathogens. Upon infection by Plasmodium berghei sporozoites, the host hepatocyte targets the invader by labelling the parasitophorous vacuole membrane (PVM) with the autophagy marker protein LC3. Until now, it has not been clear whether LC3 recruitment to the PVM is mediated by fusion of autophagosomes or by direct incorporation. To distinguish between these possibilities, we knocked out genes that are essential for autophagosome formation and for direct LC3 incorporation into membranes. The CRISPR/Cas9 system was employed to generate host cell lines deficient for either FIP200, a member of the initiation complex for autophagosome formation, or ATG5, responsible for LC3 lipidation and incorporation of LC3 into membranes. Infection of these knockout cell lines with P. berghei sporozoites revealed that LC3 recruitment to the PVM indeed depends on functional ATG5 and the elongation machinery, but not on FIP200 and the initiation complex, suggesting a direct incorporation of LC3 into the PVM. Importantly, in P. berghei-infected ATG5-/- host cells, lysosomes still accumulated at the PVM, indicating that the recruitment of lysosomes follows an LC3-independent pathway.
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Affiliation(s)
- Rahel Wacker
- Institute of Cell Biology, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Nina Eickel
- Institute of Cell Biology, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | | | - Takeshi Annoura
- Department of Parasitology, National Institute of Infectious Diseases (NIID), Tokyo, Japan
| | - Livia Niklaus
- Institute of Cell Biology, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Shahid M Khan
- Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Jun-Lin Guan
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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6
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Prado M, Eickel N, De Niz M, Heitmann A, Agop-Nersesian C, Wacker R, Schmuckli-Maurer J, Caldelari R, Janse CJ, Khan SM, May J, Meyer CG, Heussler VT. Long-term live imaging reveals cytosolic immune responses of host hepatocytes against Plasmodium infection and parasite escape mechanisms. Autophagy 2016. [PMID: 26208778 PMCID: PMC4590598 DOI: 10.1080/15548627.2015.1067361] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Plasmodium parasites are transmitted by Anopheles mosquitoes to the mammalian host and actively infect hepatocytes after passive transport in the bloodstream to the liver. In their target host hepatocyte, parasites reside within a parasitophorous vacuole (PV). In the present study it was shown that the parasitophorous vacuole membrane (PVM) can be targeted by autophagy marker proteins LC3, ubiquitin, and SQSTM1/p62 as well as by lysosomes in a process resembling selective autophagy. The dynamics of autophagy marker proteins in individual Plasmodium berghei-infected hepatocytes were followed by live imaging throughout the entire development of the parasite in the liver. Although the host cell very efficiently recognized the invading parasite in its vacuole, the majority of parasites survived this initial attack. Successful parasite development correlated with the gradual loss of all analyzed autophagy marker proteins and associated lysosomes from the PVM. However, other autophagic events like nonselective canonical autophagy in the host cell continued. This was indicated as LC3, although not labeling the PVM anymore, still localized to autophagosomes in the infected host cell. It appears that growing parasites even benefit from this form of nonselective host cell autophagy as an additional source of nutrients, as in host cells deficient for autophagy, parasite growth was retarded and could partly be rescued by the supply of additional amino acid in the medium. Importantly, mouse infections with P. berghei sporozoites confirmed LC3 dynamics, the positive effect of autophagy activation on parasite growth, and negative effects upon autophagy inhibition.
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Affiliation(s)
- Monica Prado
- b Molecular Parasitology; Bernhard Nocht Institute for Tropical Medicine ; Hamburg , Germany
| | - Nina Eickel
- a Institute of Cell Biology; University of Bern ; Bern , Switzerland
| | - Mariana De Niz
- a Institute of Cell Biology; University of Bern ; Bern , Switzerland
| | - Anna Heitmann
- b Molecular Parasitology; Bernhard Nocht Institute for Tropical Medicine ; Hamburg , Germany
| | | | - Rahel Wacker
- a Institute of Cell Biology; University of Bern ; Bern , Switzerland
| | | | - Reto Caldelari
- a Institute of Cell Biology; University of Bern ; Bern , Switzerland
| | - Chris J Janse
- c Center of Infectious Diseases; Leiden University Medical Center ; Leiden , The Netherlands
| | - Shahid M Khan
- c Center of Infectious Diseases; Leiden University Medical Center ; Leiden , The Netherlands
| | - Jürgen May
- d Infectious Disease Epidemiology; Bernhard Nocht Institute for Tropical Medicine ; Hamburg , Germany
| | - Christian G Meyer
- e Molecular Medicine; Bernhard Nocht Institute for Tropical Medicine ; Hamburg , Germany.,f Institute of Tropical Medicine; Eberhard-Karls University ; Tübingen , Germany
| | - Volker T Heussler
- a Institute of Cell Biology; University of Bern ; Bern , Switzerland
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7
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Blazkova H, von Schubert C, Mikule K, Schwab R, Angliker N, Schmuckli-Maurer J, Fernandez PC, Doxsey S, Dobbelaere DA. The IKK Inhibitor BMS-345541 Affects Multiple Mitotic Cell Cycle Transitions. Cell Cycle 2014; 6:2531-40. [PMID: 17704647 DOI: 10.4161/cc.6.20.4807] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The IkappaB kinase (IKK) complex controls processes such as inflammation, immune responses, cell survival and the proliferation of both normal and tumor cells. By activating NFkappaB, the IKK complex contributes to G1/S transition and first evidence has been presented that IKKalpha also regulates entry into mitosis. At what stage IKK is required and whether IKK also contributes to progression through mitosis and cytokinesis, however, has not yet been determined. In this study, we use BMS-345541, a potent allosteric small molecule inhibitor of IKK, to inhibit IKK specifically during G2 and during mitosis. We show that BMS-345541 affects several mitotic cell cycle transitions, including mitotic entry, prometaphase to anaphase progression and cytokinesis. Adding BMS-345541 to the cells released from arrest in S-phase blocked the activation of Aurora A, B and C, Cdk1 activation and histone H3 phosphorylation. Additionally, treatment of the mitotic cells with BMS-345541 resulted in precocious cyclin B1 and securin degradation, defective chromosome separation and improper cytokinesis. BMS-345541 was also found to override the spindle checkpoint in nocodazole-arrested cells. In vitro kinase assays using BMS-345541 indicate that these effects are not primarily due to a direct inhibitory effect of BMS-345541 on mitotic kinases such as Cdk1, Aurora A or B, Plk1 or NEK2. This study points towards a new potential role of IKK in cell cycle progression. Since deregulation of the cell cycle is one of the hallmarks of tumor formation and progression, the newly discovered level of BMS-345541 function could be useful for cell cycle control studies and may provide valuable clues for the design of future therapeutics.
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Affiliation(s)
- Hana Blazkova
- Division of Molecular Pathology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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8
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Xue G, von Schubert C, Hermann P, Peyer M, Maushagen R, Schmuckli-Maurer J, Bütikofer P, Langsley G, Dobbelaere DAE. Characterisation of gp34, a GPI-anchored protein expressed by schizonts of Theileria parva and T. annulata. Mol Biochem Parasitol 2010; 172:113-20. [PMID: 20381541 PMCID: PMC2880791 DOI: 10.1016/j.molbiopara.2010.03.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 03/29/2010] [Accepted: 03/31/2010] [Indexed: 01/01/2023]
Abstract
Using bioinformatics tools, we searched the predicted Theileria annulata and T. parva proteomes for putative schizont surface proteins. This led to the identification of gp34, a GPI-anchored protein that is stage-specifically expressed by schizonts of both Theileria species and is downregulated upon induction of merogony. Transfection experiments in HeLa cells showed that the gp34 signal peptide and GPI anchor signal are also functional in higher eukaryotes. Epitope-tagged Tp-gp34, but not Ta-gp34, expressed in the cytosol of COS-7 cells was found to localise to the central spindle and midbody. Overexpression of Tp-gp34 and Ta-gp34 induced cytokinetic defects and resulted in accumulation of binucleated cells. These findings suggest that gp34 could contribute to important parasite–host interactions during host cell division.
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Affiliation(s)
- Gondga Xue
- Division of Molecular Pathobiology, DCR-VPH, Vetsuisse Faculty, University of Bern, CH-3013 Bern, Switzerland
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9
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Schmuckli-Maurer J, Kinnaird J, Pillai S, Hermann P, McKellar S, Weir W, Dobbelaere D, Shiels B. Modulation of NF-kappaB activation in Theileria annulata-infected cloned cell lines is associated with detection of parasite-dependent IKK signalosomes and disruption of the actin cytoskeleton. Cell Microbiol 2009; 12:158-73. [PMID: 19804486 DOI: 10.1111/j.1462-5822.2009.01386.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Apicomplexan parasites within the genus Theileria have the ability to induce continuous proliferation and prevent apoptosis of the infected bovine leukocyte. Protection against apoptosis involves constitutive activation of the bovine transcription factor NF-kappaB in a parasite-dependent manner. Activation of NF-kappaB is thought to involve recruitment of IKK signalosomes at the surface of the macroschizont stage of the parasite, and it has been postulated that additional host proteins with adaptor or scaffolding function may be involved in signalosome formation. In this study two clonal cell lines were identified that show marked differences in the level of activated NF-kappaB. Further characterization of these lines demonstrated that elevated levels of activated NF-kappaB correlated with increased resistance to cell death and detection of parasite-associated IKK signalosomes, supporting results of our previous studies. Evidence was also provided for the existence of host- and parasite-dependent NF-kappaB activation pathways that are influenced by the architecture of the actin cytoskeleton. Despite this influence, it appears that the primary event required for formation of the parasite-dependent IKK signalosome is likely to be an interaction between a signalosome component and a parasite-encoded surface ligand.
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Affiliation(s)
- Jacqueline Schmuckli-Maurer
- Division of Molecular Pathobiology, Department of Clinical Research and VPH, Vetsuisse Faculty Bern, Bern, Switzerland
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10
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Schmuckli-Maurer J, Casanova C, Schmied S, Affentranger S, Parvanova I, Kang'a S, Nene V, Katzer F, McKeever D, Müller J, Bishop R, Pain A, Dobbelaere DAE. Expression analysis of the Theileria parva subtelomere-encoded variable secreted protein gene family. PLoS One 2009; 4:e4839. [PMID: 19325907 PMCID: PMC2657828 DOI: 10.1371/journal.pone.0004839] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Accepted: 02/04/2009] [Indexed: 11/23/2022] Open
Abstract
Background The intracellular protozoan parasite Theileria parva transforms bovine lymphocytes inducing uncontrolled proliferation. Proteins released from the parasite are assumed to contribute to phenotypic changes of the host cell and parasite persistence. With 85 members, genes encoding subtelomeric variable secreted proteins (SVSPs) form the largest gene family in T. parva. The majority of SVSPs contain predicted signal peptides, suggesting secretion into the host cell cytoplasm. Methodology/Principal Findings We analysed SVSP expression in T. parva-transformed cell lines established in vitro by infection of T or B lymphocytes with cloned T. parva parasites. Microarray and quantitative real-time PCR analysis revealed mRNA expression for a wide range of SVSP genes. The pattern of mRNA expression was largely defined by the parasite genotype and not by host background or cell type, and found to be relatively stable in vitro over a period of two months. Interestingly, immunofluorescence analysis carried out on cell lines established from a cloned parasite showed that expression of a single SVSP encoded by TP03_0882 is limited to only a small percentage of parasites. Epitope-tagged TP03_0882 expressed in mammalian cells was found to translocate into the nucleus, a process that could be attributed to two different nuclear localisation signals. Conclusions Our analysis reveals a complex pattern of Theileria SVSP mRNA expression, which depends on the parasite genotype. Whereas in cell lines established from a cloned parasite transcripts can be found corresponding to a wide range of SVSP genes, only a minority of parasites appear to express a particular SVSP protein. The fact that a number of SVSPs contain functional nuclear localisation signals suggests that proteins released from the parasite could contribute to phenotypic changes of the host cell. This initial characterisation will facilitate future studies on the regulation of SVSP gene expression and the potential biological role of these enigmatic proteins.
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Affiliation(s)
| | - Carlo Casanova
- Molecular Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Stéfanie Schmied
- Molecular Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Sarah Affentranger
- Molecular Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Iana Parvanova
- Molecular Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Simon Kang'a
- The Institute for Genomic Research (TIGR), Rockville, Maryland, United States of America
| | - Vishvanath Nene
- The Institute for Genomic Research (TIGR), Rockville, Maryland, United States of America
| | - Frank Katzer
- Centre for Tropical Veterinary Medicine, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Veterinary Centre, Roslin, Midlothian, United Kingdom
| | - Declan McKeever
- Centre for Tropical Veterinary Medicine, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Veterinary Centre, Roslin, Midlothian, United Kingdom
| | - Joachim Müller
- Institute of Parasitology, University of Bern, Bern, Switzerland
| | - Richard Bishop
- International Livestock Research Institute, Nairobi, Kenya
| | - Arnab Pain
- Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Dirk A. E. Dobbelaere
- Molecular Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- * E-mail:
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11
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Stoller P, Marti D, Schmuckli-Maurer J, Dobbelaere D, Frenz M. Multiphoton imaging of ultrashort pulse laser ablation in the intracellular parasite Theileria. J Biomed Opt 2008; 13:044021. [PMID: 19021349 DOI: 10.1117/1.2960524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Theileria annulata is an intracellular parasite that infects and transforms bovine leukocytes, inducing continuous proliferation of its host cell both in vivo and in vitro. Theileria-infected cells can easily be propagated in the laboratory and serve as a good model for laser ablation studies. Using single pulses from an amplified ultrashort pulse laser system, we developed a technique to introduce submicrometer holes in the plasma membrane of the intracellular schizont stage of Theileria annulata. This was achieved without compromising either the viability of the organisms or that of the host cell that harbors the parasite in its cytoplasm. Multiphoton microscopy was used to generate image stacks of the parasite before and after ablation. The high axial resolution allowed precise selection of the region of the membrane that was ablated. It also allowed observation of the size of the holes generated (in fixed, stained cells) and determination of the structural changes in the parasite resulting from the laser pulses (in living cells in vitro). This technique opens a new possibility for the transfection of Theileria or delivery of molecules to the schizont that may prove useful in the study of this special host-parasite relationship.
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Affiliation(s)
- Patrick Stoller
- University of Bern, Institute of Applied Physics, Sidlerstrasse 5, Bern, Switzerland
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Schmuckli-Maurer J, Shiels B, Dobbelaere DA. Stochastic induction of Theileria annulata merogony in vitro by chloramphenicol. Int J Parasitol 2008; 38:1705-15. [PMID: 18573257 DOI: 10.1016/j.ijpara.2008.05.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 05/16/2008] [Indexed: 11/29/2022]
Abstract
Theileria annulata inhabits the cytoplasm of bovine leukocytes where it can be found as a multinucleated schizont. The schizont is the pathogenic stage of the life cycle and by interfering with host signalling pathways, it induces unlimited host cell proliferation and protection against apoptosis. In the infected animal, the schizont differentiates to the merozoite life cycle stage in a process called merogony. This takes place within the host leukocyte, resulting in the production of merozoites that are subsequently released by leukocyte lysis. In established cultures of T. annulata-transformed cells, merogony does not spontaneously occur, but the process can be activated by a shift in temperature. In this study we show that chloramphenicol induces schizont differentiation in proliferating T. annulata-transformed cells. We demonstrate that chloramphenicol-induced merogony is inherently asynchronous and has a quantitative basis. The process is accompanied by the down-regulation of schizont-specific surface proteins, de novo expression of merozoite-specific markers such as Tamr1 and Tams1 and the morphological hallmarks of merogony. Chloramphenicol-induced parasite differentiation was found to be associated with diminished proliferation potential and extensive morphological changes of the host cell, including increased numbers of pseudopodia. Significantly, chloramphenicol treatment can accelerate merogony induced by elevated temperature, supporting postulation that the differentiation event is a stochastic process that can be manipulated to alter the outcome of parasitic infection.
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Affiliation(s)
- Jacqueline Schmuckli-Maurer
- Division of Molecular Pathobiology, Department of Clinical Research and VPH, Vetsuisse Faculty Bern, CH-3012 Bern, Switzerland
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Abstract
The RAD54 gene of Saccharomyces cerevisiae encodes a conserved dsDNA-dependent ATPase of the Swi2/Snf2 family with a specialized function during recombinational DNA repair. Here we analyzed the consequences of the loss of Rad54 function in vegetative (mitotic) cells. Mutants in RAD54 exhibited drastically reduced rates of spontaneous intragenic recombination but were proficient for spontaneous intergenic recombinant formation. The intergenic recombinants likely arose by a RAD54-independent pathway of break-induced replication. Significantly increased rates of spontaneous chromosome loss for diploid rad54/rad54 cells were identified in several independent assays. Inter estingly, the increase in chromosome loss appeared to depend on the presence of a homolog. In addition, the rate of complex genetic events involving chromosome loss were drastically increased in diploid rad54/rad54 cells. Together, these data suggest a role for Rad54 protein in the repair of spontaneous damage, where in the absence of Rad54 protein, homologous recombination is initiated but not properly terminated, leading to misrepair and chromosome loss.
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Rottenberg S, Schmuckli-Maurer J, Grimm S, Heussler VT, Dobbelaere DAE. Characterization of the bovine IkappaB kinases (IKK)alpha and IKKbeta, the regulatory subunit NEMO and their substrate IkappaBalpha. Gene 2002; 299:293-300. [PMID: 12459277 DOI: 10.1016/s0378-1119(02)01011-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The Nuclear factor (NF)-kappaB signalling pathway plays a critical role in the regulation and coordination of a wide range of cellular events such as cell growth, apoptosis and cell differentiation. Activation of the IKK (inhibitor of NF-kappaB kinase) complex is a crucial step and a point of convergence of all known NF-kappaB signalling pathways. To analyse bovine IKKalpha (IKK1), IKKbeta (IKK2) and IKKgamma (or NF-kappaB Essential MOdulator, NEMO) and their substrate IkappaBalpha (Inhibitor of NF-kappaB), the corresponding cDNAs of these molecules were isolated, sequenced and characterized. A comparison of the amino acid sequences with those of their orthologues in other species showed a very high degree of identity, suggesting that the IKK complex and its substrate IkappaBalpha are evolutionarily highly conserved components of the NF-kappaB pathway. Bovine IKKalpha and IKKbeta are related protein kinases showing 50% identity which is especially prominent in the kinase and leucine zipper domains. Co-immunoprecipitation assays and GST-pull-down experiments were carried out to determine the composition of bovine IKK complexes compared to that in human Jurkat T cells. Using these approaches, the presence of bovine IKK complexes harbouring IKKalpha, IKKbeta, NEMO and the interaction of IKK with its substrate IkappaBalpha could be demonstrated. Parallel experiments using human Jurkat T cells confirmed the high degree of conservation also at the level of protein-protein interactions. Finally, a yeast two-hybrid analysis showed that bovine NEMO molecules, in addition to the binding to IKKalpha and IKKbeta, also strongly interact with each other.
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Affiliation(s)
- Sven Rottenberg
- Institute of Animal Pathology, Molecular Pathology, University of Berne, Länggassstrasse 122, CH-3012 Berne, Switzerland
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Walsh L, Schmuckli-Maurer J, Billinton N, Barker MG, Heyer WD, Walmsley RM. DNA-damage induction of RAD54 can be regulated independently of the RAD9- and DDC1-dependent checkpoints that regulate RNR2. Curr Genet 2002; 41:232-40. [PMID: 12172964 DOI: 10.1007/s00294-002-0302-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2002] [Accepted: 03/04/2002] [Indexed: 11/24/2022]
Abstract
DNA damage checkpoints regulate a number of physiological responses after DNA damage. The transcriptional level of many genes is specifically induced in response to genotoxic stress in a checkpoint-dependent manner. The regulation of DNA damage-induced transcription of RAD54 and RNR2 by RAD9, DDC1, DUN1, CRT1 and MBP1 was investigated in Saccharomyces cerevisiae, using green fluorescent protein reporter assays and Northern blots. RAD54 and RNR2 reporter activity in response to the DNA damaging agent, methyl methanesulphonate, was measured in ddc1-Delta, rad9-Delta, ddc1-Delta/rad9-Delta, dun1-Delta, crt1-Delta and mbp1-Delta mutants and was compared with that of the wild type. RAD9 and DDC1 were shown to be required for a full RNR2 transcriptional response, although with the double mutant, ddc1-Delta/rad9-Delta, no additive effect on RNR2 induction was observed. RAD54 promoter activity was not significantly reduced in either rad9-Delta or ddc1-Delta mutants and was only partially reduced in the rad9-Delta/ddc1-Delta strain, suggesting that DNA damage induction of RAD54 must depend on other genes, in addition to RAD9 and DDC1. In the dun1-Delta mutant, RNR2 promoter activity was lowered, whilst that of RAD54 was increased, confirming that DUN1 is required for transcriptional induction of RNR2, but is not required for damage-induced transcription of RAD54. Analysis of the crt1-Delta strain confirmed that RNR2 is regulated via the CRT1 repressor pathway, downstream of DUN1, but RAD54 is not. MBP1 was shown to be required for transcription of RNR2, but was not needed for transcription of RAD54. These results indicate that RNR2 and RAD54 are regulated in different ways.
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Affiliation(s)
- Lindsey Walsh
- Department of Biomolecular Sciences, UMIST, PO Box 88, Manchester, M60 1QD, UK
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Reubi JC, Wenger S, Schmuckli-Maurer J, Schaer JC, Gugger M. Bombesin receptor subtypes in human cancers: detection with the universal radioligand (125)I-[D-TYR(6), beta-ALA(11), PHE(13), NLE(14)] bombesin(6-14). Clin Cancer Res 2002; 8:1139-46. [PMID: 11948125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
PURPOSE Bombesin and bombesin receptors have been shown to play a role in cancer. Whereas the gastrin-releasing peptide (GRP) receptor is a bombesin receptor subtype frequently expressed by tumors, the other three subtypes, the neuromedin B (NMB), BB3, and BB4 receptors, have been poorly investigated in human tissues. EXPERIMENTAL DESIGN We investigated 161 human tumors for their bombesin receptor subtype expression using in vitro receptor autoradiography with the universal bombesin radioligand (125)I-[D-Tyr(6), beta-Ala(11), Phe(13), Nle(14)]bombesin(6-14) in displacement experiments with unlabeled GRP, bombesin, NMB, and [D-Tyr(6), beta-Ala(11), Phe(13), Nle(14)]bombesin(6-14). The distinct rank order of potencies of these analogues for each receptor subtype allows us to identify the predominant subtype expressed by each tumor. RESULTS Twelve of 12 prostate cancers, 41 of 57 breast cancers, and 5 of 5 gastrinomas expressed predominantly GRP receptors; 11 of 24 intestinal, 1 of 26 bronchial, and 1 of 1 thymic carcinoids had preferentially NMB receptors; 9 of 26 bronchial carcinoids, 1 large cell neuroendocrine lung carcinoma, and 4 of 9 small cell lung carcinomas had preferentially BB3 receptors, whereas 3 of 9 small cell lung carcinomas had GRP receptors. Renal cell carcinomas had GRP receptors in 6 of 16 cases and BB3 receptors in 4 of 16 cases. Finally, 2 of 10 Ewing sarcomas had BB3 receptors. In situ hybridization detected BB3 receptor mRNA in neuroendocrine tumors expressing the BB3 protein. CONCLUSIONS This is the first study detecting the proteins of BB3, NMB, and GRP receptors in a group of human tumors using differential binding techniques. Particularly relevant is the BB3 expression in lung carcinoids and other neuroendocrine lung tumors, whereas gastrointestinal carcinoids preferably express NMB receptors. These tumors may be targets for diagnostic and radiotherapeutic applications of subtype-selective bombesin analogues.
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Affiliation(s)
- Jean Claude Reubi
- Division of Cell Biology and Experimental Cancer Research, Institute of Pathology, University of Berne, CH-3010 Berne, Switzerland.
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Abstract
The Rad54 protein is an important component of the recombinational DNA repair pathway in vegetative Saccharomyces cerevisiae cells. Unlike those in other members of the RAD52 group, the meiotic defect in rad54 is rather mild, reducing spore viability only to 26%-65%. A consistently greater requirement for Rad54p during meiosis was observed in hybrid strains, suggesting that Rad54p has a certain role in interhomolog interactions. Such a role is probably minor as no recombination defects were found in the surviving gametes in three genetic intervals on chromosome V. Also, the spore viability pattern in tetrads did not reflect an increase in nondisjunction at meiosis I indicative of a meiotic recombination defect. We suggest that the meiotic defect of rad54 cells lies in the failure to repair meiosis-specific double-strand breaks outside the context of the highly differentiated pathway leading to interhomolog joint molecules and meiotic crossovers that ensure accurate segregation at meiosis I.
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Abstract
Checkpoints, which are integral to the cellular response to DNA damage, coordinate transient cell cycle arrest and the induced expression of DNA repair genes after genotoxic stress. DNA repair ensures cellular survival and genomic stability, utilizing a multipathway network. Here we report evidence that the two systems, DNA damage checkpoint control and DNA repair, are directly connected by demonstrating that the Rad55 double-strand break repair protein of the recombinational repair pathway is a terminal substrate of DNA damage and replication block checkpoints. Rad55p was specifically phosphorylated in response to DNA damage induced by the alkylating agent methyl methanesulfonate, dependent on an active DNA damage checkpoint. Rad55p modification was also observed after gamma ray and UV radiation. The rapid time course of phosphorylation and the recombination defects identified in checkpoint-deficient cells are consistent with a role of the DNA damage checkpoint in activating recombinational repair. Rad55p phosphorylation possibly affects the balance between different competing DNA repair pathways.
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Affiliation(s)
- V I Bashkirov
- Institute of General Microbiology, CH-3012 Bern, Switzerland
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Clever B, Schmuckli-Maurer J, Sigrist M, Glassner BJ, Heyer WD. Specific negative effects resulting from elevated levels of the recombinational repair protein Rad54p in Saccharomyces cerevisiae. Yeast 1999; 15:721-40. [PMID: 10398342 DOI: 10.1002/(sici)1097-0061(19990630)15:9<721::aid-yea414>3.0.co;2-w] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
RAD54 is an important gene in the RAD52 group that controls recombinational repair of DNA damage in Saccharomyces cerevisiae. Rad54p is a DNA-dependent ATPase and shares seven conserved sequence motifs with proteins of the Swi2p/Snf2p family. Genetic analysis of mutations in motif IA, the putative ATP-binding fold of Rad54p, demonstrated the functional importance of this motif. Overexpression of these mutant proteins resulted in strong, dominant-negative effects on cell survival. High levels of full-length wild-type Rad54p or specific parts of Rad54p also resulted in negative effects, dependent on the ploidy of the host cell. This differential effect was not under a/alpha mating-type control. Deletion of the RAD54 gene led to a small but significant increase in the mutation rate. However, the negative overexpression effects in haploid cells could not be explained by an accumulation of (recessive) lethal mutations. All negative overexpression effects were found to be enhanced under genotoxic stress. We suggest that the negative overexpression effects are the result of unbalanced protein-protein interactions, indicating that Rad54p is involved in multiple interactions, dependent on the physiological situation. Diploid wild-type cells contained an estimated 7000 Rad54p molecules/cell, whereas haploid cells about 3500/cell. Rad54p levels were highest in actively growing cells compared to stationary phase cells. Rad54 protein levels were found to be elevated after DNA damage.
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Affiliation(s)
- B Clever
- Institute for General Microbiology, University of Bern, Bern, Switzerland
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Schmuckli-Maurer J, Heyer WD. The Saccharomyces cerevisiae RAD54 gene is important but not essential for natural homothallic mating-type switching. Mol Gen Genet 1999; 260:551-8. [PMID: 9928934 DOI: 10.1007/s004380050928] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Homothallic Saccharomyces cerevisiae strains switch their mating-type in a specific gene conversion event induced by a DNA double strand break made by the HO endonuclease. The RAD52 group genes control recombinational repair of DNA double strand breaks, and we examined their role in native homothallic mating-type switching. Surprisingly, we found that the Rad54 protein was important but not essential for mating-type switching under natural conditions. As an upper limit, we estimate that 29% of the rad54 spore clones can successfully switch their mating-type. The RAD55 and RAD57 gene products were even less important, but their presence increased the efficiency of the process. In contrast, the RAD51 and RAD52 genes are essential for homothallic mating-type switching. We propose that mating-type switching in RAD54 mutants occurs stochastically with a low probability, possibly reflecting different states of chromosomal structure.
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Clever B, Interthal H, Schmuckli-Maurer J, King J, Sigrist M, Heyer WD. Recombinational repair in yeast: functional interactions between Rad51 and Rad54 proteins. EMBO J 1997; 16:2535-44. [PMID: 9171366 PMCID: PMC1169853 DOI: 10.1093/emboj/16.9.2535] [Citation(s) in RCA: 148] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Rad51p is a eukaryotic homolog of RecA, the central homologous pairing and strand exchange protein in Escherichia coli. Rad54p belongs to the Swi2p/Snf2p family of DNA-stimulated ATPases. Both proteins are also important members of the RAD52 group which controls recombinational DNA damage repair of double-strand breaks and other DNA lesions in Saccharomyces cerevisiae. Here we demonstrate by genetic, molecular and biochemical criteria that Rad51 and Rad54 proteins interact. Strikingly, overexpression of Rad54p can functionally suppress the UV and methyl methanesulfonate sensitivity caused by a deletion of the RAD51 gene. However, no suppression was observed for the defects of rad51 cells in the repair of gamma-ray-induced DNA damage, mating type switching or spontaneous hetero-allelic recombination. This suppression is genetically dependent on the presence of two other members of the recombinational repair group, RAD55 and RAD57. Our data provide compelling evidence that Rad51 and Rad54 proteins interact in vivo and that this interaction is functionally important for recombinational DNA damage repair. As both proteins are conserved throughout evolution from yeasts to humans, a similar protein-protein interaction may be expected in other organisms.
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Affiliation(s)
- B Clever
- Institute of General Microbiology, Bern, Switzerland
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