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Mielecki D, Detman A, Aleksandrzak-Piekarczyk T, Widomska M, Chojnacka A, Stachurska-Skrodzka A, Walczak P, Grzesiuk E, Sikora A. Unlocking the genome of the non-sourdough Kazachstania humilis MAW1: insights into inhibitory factors and phenotypic properties. Microb Cell Fact 2024; 23:111. [PMID: 38622625 PMCID: PMC11017505 DOI: 10.1186/s12934-024-02380-7] [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: 12/29/2023] [Accepted: 03/22/2024] [Indexed: 04/17/2024] Open
Abstract
BACKGROUND Ascomycetous budding yeasts are ubiquitous environmental microorganisms important in food production and medicine. Due to recent intensive genomic research, the taxonomy of yeast is becoming more organized based on the identification of monophyletic taxa. This includes genera important to humans, such as Kazachstania. Until now, Kazachstania humilis (previously Candida humilis) was regarded as a sourdough-specific yeast. In addition, any antibacterial activity has not been associated with this species. RESULTS Previously, we isolated a yeast strain that impaired bio-hydrogen production in a dark fermentation bioreactor and inhibited the growth of Gram-positive and Gram-negative bacteria. Here, using next generation sequencing technologies, we sequenced the genome of this strain named K. humilis MAW1. This is the first genome of a K. humilis isolate not originating from a fermented food. We used novel phylogenetic approach employing the 18 S-ITS-D1-D2 region to show the placement of the K. humilis MAW1 among other members of the Kazachstania genus. This strain was examined by global phenotypic profiling, including carbon sources utilized and the influence of stress conditions on growth. Using the well-recognized bacterial model Escherichia coli AB1157, we show that K. humilis MAW1 cultivated in an acidic medium inhibits bacterial growth by the disturbance of cell division, manifested by filament formation. To gain a greater understanding of the inhibitory effect of K. humilis MAW1, we selected 23 yeast proteins with recognized toxic activity against bacteria and used them for Blast searches of the K. humilis MAW1 genome assembly. The resulting panel of genes present in the K. humilis MAW1 genome included those encoding the 1,3-β-glucan glycosidase and the 1,3-β-glucan synthesis inhibitor that might disturb the bacterial cell envelope structures. CONCLUSIONS We characterized a non-sourdough-derived strain of K. humilis, including its genome sequence and physiological aspects. The MAW1, together with other K. humilis strains, shows the new organization of the mating-type locus. The revealed here pH-dependent ability to inhibit bacterial growth has not been previously recognized in this species. Our study contributes to the building of genome sequence-based classification systems; better understanding of K.humilis as a cell factory in fermentation processes and exploring bacteria-yeast interactions in microbial communities.
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Affiliation(s)
- Damian Mielecki
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, Warsaw, 02-106, Poland
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Pawińskiego 5, Warsaw, 02-106, Poland
| | - Anna Detman
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, Warsaw, 02-106, Poland
| | | | - Małgorzata Widomska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, Warsaw, 02-106, Poland
| | - Aleksandra Chojnacka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, Warsaw, 02-106, Poland
- Institute of Biology, Warsaw University of Life Sciences, Nowoursynowska 159, Warsaw, 02-776, Poland
| | | | - Paulina Walczak
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, Warsaw, 02-106, Poland
| | - Elżbieta Grzesiuk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, Warsaw, 02-106, Poland
| | - Anna Sikora
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, Warsaw, 02-106, Poland.
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2
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Smejda M, Kądziołka D, Radczuk N, Krutyhołowa R, Chramiec-Głąbik A, Kędracka-Krok S, Jankowska U, Biela A, Glatt S. Same but different - Molecular comparison of human KTI12 and PSTK. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:118945. [PMID: 33417976 DOI: 10.1016/j.bbamcr.2020.118945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 12/01/2020] [Accepted: 12/23/2020] [Indexed: 11/18/2022]
Abstract
Kti12 and PSTK are closely related and highly similar proteins implicated in different aspects of tRNA metabolism. Kti12 has been identified as an essential regulatory factor of the Elongator complex, involved in the modification of uridine bases in eukaryotic tRNAs. PSTK phosphorylates the tRNASec-bound amino acid serine, which is required to synthesize selenocysteine. Kti12 and PSTK have previously been studied independently in various organisms, but only appear simultaneously in some animalia, including humans. As Kti12- and PSTK-related pathways are clinically relevant, it is of prime importance to understand their biological functions and mutual relationship in humans. Here, we use different tRNA substrates to directly compare the enzymatic activities of purified human KTI12 and human PSTK proteins. Our complementary Co-IP and BioID2 approaches in human cells confirm that Elongator is the main interaction partner of KTI12 but additionally indicate potential links to proteins involved in vesicular transport, RNA metabolism and deubiquitination. Moreover, we identify and validate a yet uncharacterized interaction between PSTK and γ-taxilin. Foremost, we demonstrate that human KTI12 and PSTK do not share interactors or influence their respective biological functions. Our data provide a comprehensive analysis of the regulatory networks controlling the activity of the human Elongator complex and selenocysteine biosynthesis.
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Affiliation(s)
- Marta Smejda
- Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland; Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Dominika Kądziołka
- Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland
| | - Natalia Radczuk
- Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland
| | - Rościsław Krutyhołowa
- Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland; Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | | | - Sylwia Kędracka-Krok
- Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland; Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Urszula Jankowska
- Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland
| | - Anna Biela
- Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland.
| | - Sebastian Glatt
- Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland.
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3
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Wang H, Xu C, Zhang Y, Yan X, Jin X, Yao X, Chen P, Zheng B. PtKTI12 genes influence wobble uridine modifications and drought stress tolerance in hybrid poplar. TREE PHYSIOLOGY 2020; 40:1778-1791. [PMID: 32705117 DOI: 10.1093/treephys/tpaa088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 07/13/2020] [Indexed: 06/11/2023]
Abstract
The multisubunit Elongator complex plays key roles in transcription by interacting with RNA polymerase II and chromatin modeling. Kti proteins have been identified as the auxiliary protein for the Elongator complex. However, our knowledge of Kti proteins in woody plants remains limited. In this study, in total 16 KTI gene homologs were identified in Populus trichocarpa. Among them, the two KTI12 candidates were named PtKTI12A and PtKTI12B. Although PtKTI12A and PtKTI12B were largely different in gene expression level and tissue specificity, both genes were induced by heat and drought stresses. PtKTI12A and PtKTI12B RNAi transgenic poplar plants showed reduced levels of modified nucleosides, in particular 5-carbamoylmethyluridine and 5-methoxycarbonylmethyl-2-thiouridine. Meanwhile, their tolerance to drought was improved when subjected to withdrawal of watering. Also, the protein products of PtKTI12A and PtKTI12B had similar subcellular localization and predicted tertiary structure. The results suggest that Kti12 proteins are involved in tRNA wobble uridine modification, stress response and drought stress tolerance in hybrid poplar.
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Affiliation(s)
- Hailang Wang
- College of Plant Science and Technology, Huazhong Agricultural University, Xueyuan Rd, Wuhan 430070, China
| | - Chao Xu
- Yuan Longping High-Tech Agriculture Co. Ltd., No. 638, Heping Rd, Changsha 410001, China
| | - Youbing Zhang
- Guangzhou Vipotion Biotechnology Co. Ltd., 5F, Building J5, No.1 Jiantashan Road, Guangzhou Science Park, Guangzhou 510663, China
| | - Xu Yan
- Shacheng Middle School, Longtan W St, Zhangjiakou 075000, China
| | - Xiaohuan Jin
- College of Plant Science and Technology, Huazhong Agricultural University, Xueyuan Rd, Wuhan 430070, China
| | - Xiaoqing Yao
- College of Plant Science and Technology, Huazhong Agricultural University, Xueyuan Rd, Wuhan 430070, China
| | - Peng Chen
- College of Plant Science and Technology, Huazhong Agricultural University, Xueyuan Rd, Wuhan 430070, China
| | - Bo Zheng
- Key Laboratory of Horticultural Plant Biology of Ministry of Education, College of Horticultural and Forestry Sciences, Huazhong Agricultural University, Xueyuan Rd, Wuhan 430070, China
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4
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Plant Elongator-Protein Complex of Diverse Activities Regulates Growth, Development, and Immune Responses. Int J Mol Sci 2020; 21:ijms21186912. [PMID: 32971769 PMCID: PMC7555253 DOI: 10.3390/ijms21186912] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/16/2020] [Accepted: 09/18/2020] [Indexed: 12/23/2022] Open
Abstract
Contrary to the conserved Elongator composition in yeast, animals, and plants, molecular functions and catalytic activities of the complex remain controversial. Elongator was identified as a component of elongating RNA polymerase II holoenzyme in yeast, animals, and plants. Furthermore, it was suggested that Elonagtor facilitates elongation of transcription via histone acetyl transferase activity. Accordingly, phenotypes of Arabidopsis elo mutants, which show development, growth, or immune response defects, correlate with transcriptional downregulation and the decreased histone acetylation in the coding regions of crucial genes. Plant Elongator was also implicated in other processes: transcription and processing of miRNA, regulation of DNA replication by histone acetylation, and acetylation of alpha-tubulin. Moreover, tRNA modification, discovered first in yeast and confirmed in plants, was claimed as the main activity of Elongator, leading to specificity in translation that might also result indirectly in a deficiency in transcription. Heterologous overexpression of individual Arabidopsis Elongator subunits and their respective phenotypes suggest that single Elongator subunits might also have another function next to being a part of the complex. In this review, we shall present the experimental evidence of all molecular mechanisms and catalytic activities performed by Elongator in nucleus and cytoplasm of plant cells, which might explain how Elongator regulates growth, development, and immune responses.
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5
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Krutyhołowa R, Reinhardt-Tews A, Chramiec-Głąbik A, Breunig KD, Glatt S. Fungal Kti12 proteins display unusual linker regions and unique ATPase p-loops. Curr Genet 2020; 66:823-833. [PMID: 32236652 PMCID: PMC7363723 DOI: 10.1007/s00294-020-01070-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/13/2020] [Accepted: 03/19/2020] [Indexed: 12/24/2022]
Abstract
Kti12 (Kluyveromyces lactis toxin insensitive 12) is an evolutionary highly conserved ATPase, crucial for the tRNA-modification activity of the eukaryotic Elongator complex. The protein consists of an N-terminal ATPase and a C-terminal tRNA-binding domain, which are connected by a flexible linker. The precise role of the linker region and its involvement in the communication between the two domains and their activities remain elusive. Here, we analyzed all available Kti12 protein sequences and report the discovery of a subset of Kti12 proteins with abnormally long linker regions. These Kti12 proteins are characterized by a co-occurring lysine to leucine substitution in their Walker A motif, previously thought to be invariable. We show that the K14L substitution lowers the affinity to ATP, but does not affect the catalytic activity of Kti12 at high ATP concentrations. We compare the activity of mutated variants of Kti12 in vitro with complementation assays in vivo in yeast. Ultimately, we compared Kti12 to other known p-loop ATPase family members known to carry a similar deviant Walker A motif. Our data establish Kti12 of Eurotiomycetes as an example of eukaryotic ATPase harboring a significantly deviating but still functional Walker A motif.
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Affiliation(s)
- Rościsław Krutyhołowa
- Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland.,Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | | | | | - Karin D Breunig
- Institut für Biologie, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany.
| | - Sebastian Glatt
- Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland.
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6
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Krutyhołowa R, Hammermeister A, Zabel R, Abdel-Fattah W, Reinhardt-Tews A, Helm M, Stark MJR, Breunig KD, Schaffrath R, Glatt S. Kti12, a PSTK-like tRNA dependent ATPase essential for tRNA modification by Elongator. Nucleic Acids Res 2019; 47:4814-4830. [PMID: 30916349 PMCID: PMC6511879 DOI: 10.1093/nar/gkz190] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 02/14/2019] [Accepted: 03/11/2019] [Indexed: 01/08/2023] Open
Abstract
Posttranscriptional RNA modifications occur in all domains of life. Modifications of anticodon bases are of particular importance for ribosomal decoding and proteome homeostasis. The Elongator complex modifies uridines in the wobble position and is highly conserved in eukaryotes. Despite recent insights into Elongator's architecture, the structure and function of its regulatory factor Kti12 have remained elusive. Here, we present the crystal structure of Kti12′s nucleotide hydrolase domain trapped in a transition state of ATP hydrolysis. The structure reveals striking similarities to an O-phosphoseryl-tRNA kinase involved in the selenocysteine pathway. Both proteins employ similar mechanisms of tRNA binding and show tRNASec-dependent ATPase activity. In addition, we demonstrate that Kti12 binds directly to Elongator and that ATP hydrolysis is crucial for Elongator to maintain proper tRNA anticodon modification levels in vivo. In summary, our data reveal a hitherto uncharacterized link between two translational control pathways that regulate selenocysteine incorporation and affect ribosomal tRNA selection via specific tRNA modifications.
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Affiliation(s)
- Rościsław Krutyhołowa
- Max Planck Research Group at the Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland.,Department of Cell Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | | | - Rene Zabel
- Institut für Biologie, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
| | - Wael Abdel-Fattah
- Institut für Biologie, FG Mikrobiologie, Universität Kassel, Kassel, Germany
| | | | - Mark Helm
- Institut für Pharmazie und Biochemie, Universität Mainz, Mainz, Germany
| | - Michael J R Stark
- Centre for Gene Regulation & Expression, University of Dundee, Dundee, UK
| | - Karin D Breunig
- Institut für Biologie, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
| | - Raffael Schaffrath
- Institut für Biologie, FG Mikrobiologie, Universität Kassel, Kassel, Germany
| | - Sebastian Glatt
- Max Planck Research Group at the Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
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7
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Klamt A, Nagarathinam K, Tanabe M, Kumar A, Balbach J. Hyperbolic Pressure-Temperature Phase Diagram of the Zinc-Finger Protein apoKti11 Detected by NMR Spectroscopy. J Phys Chem B 2019; 123:792-801. [PMID: 30608169 DOI: 10.1021/acs.jpcb.8b11019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
For a comprehensive understanding of the thermodynamic state functions describing the stability of a protein, the influence of the intensive properties of temperature and pressure has to be known. With the zinc-finger-containing Kti11, we found a suitable protein for this purpose because folding and unfolding transitions occur at an experimentally accessible temperature (280-330 °K) and pressure (0.1-240 MPa) range. We solved the crystal structure of the apo form of Kti11 to reveal two disulfide bonds at the metal-binding site, which seals off a cavity in the β-barrel part of the protein. From a generally applicable proton NMR approach, we could determine the populations of folded and unfolded chains under all conditions, leading to a hyperbolic pressure-temperature phase diagram rarely observed for proteins. A global fit of a two-state model to all derived populations disclosed reliable values for the change in Gibbs free energy, volume, entropy, heat capacity, compressibility, and thermal expansion upon unfolding. The unfolded state of apoKti11 has a lower compressibility compared to the native state and a smaller volume at ambient pressure. Therefore, a pressure increase up to 200 MPa reduces the population of the native state, and above this value, the native population increases again. Pressure-induced chemical-shift changes in two-dimensional 1H-15N NMR spectra could be employed for a molecular interpretation of the thermodynamic properties of apoKti11.
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Affiliation(s)
- Andi Klamt
- Institute of Physics, Biophysics , Martin-Luther University Halle-Wittenberg , Betty-Heimann Street 7 , 06120 Halle , Germany
| | - Kumar Nagarathinam
- HALOmem, Membrane Protein Biochemistry , Martin-Luther-University Halle-Wittenberg , Kurt-Mothes-Street 3 , 06120 Halle (Saale) , Germany.,Institute of Virology , Hannover Medical School , Carl-Neuberg-Straße 1 , D-30625 Hannover , Germany
| | - Mikio Tanabe
- HALOmem, Membrane Protein Biochemistry , Martin-Luther-University Halle-Wittenberg , Kurt-Mothes-Street 3 , 06120 Halle (Saale) , Germany.,Structural Biology Research Center, Institute of Materials Structure Science , KEK/High Energy Accelerator Research Organization , 1-1 Oho , Tsukuba , Ibaraki , 305-0801 , Japan
| | - Amit Kumar
- Institute of Physics, Biophysics , Martin-Luther University Halle-Wittenberg , Betty-Heimann Street 7 , 06120 Halle , Germany.,Department of Diabetes, Faculty of Lifesciences and Medicine , King's College London , Great Maze Pond , London SE1 1UL , U.K
| | - Jochen Balbach
- Institute of Physics, Biophysics , Martin-Luther University Halle-Wittenberg , Betty-Heimann Street 7 , 06120 Halle , Germany.,HALOmem, Membrane Protein Biochemistry , Martin-Luther-University Halle-Wittenberg , Kurt-Mothes-Street 3 , 06120 Halle (Saale) , Germany
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8
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Roles of Elongator Dependent tRNA Modification Pathways in Neurodegeneration and Cancer. Genes (Basel) 2018; 10:genes10010019. [PMID: 30597914 PMCID: PMC6356722 DOI: 10.3390/genes10010019] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/18/2018] [Accepted: 12/20/2018] [Indexed: 02/07/2023] Open
Abstract
Transfer RNA (tRNA) is subject to a multitude of posttranscriptional modifications which can profoundly impact its functionality as the essential adaptor molecule in messenger RNA (mRNA) translation. Therefore, dynamic regulation of tRNA modification in response to environmental changes can tune the efficiency of gene expression in concert with the emerging epitranscriptomic mRNA regulators. Several of the tRNA modifications are required to prevent human diseases and are particularly important for proper development and generation of neurons. In addition to the positive role of different tRNA modifications in prevention of neurodegeneration, certain cancer types upregulate tRNA modification genes to sustain cancer cell gene expression and metastasis. Multiple associations of defects in genes encoding subunits of the tRNA modifier complex Elongator with human disease highlight the importance of proper anticodon wobble uridine modifications (xm⁵U34) for health. Elongator functionality requires communication with accessory proteins and dynamic phosphorylation, providing regulatory control of its function. Here, we summarized recent insights into molecular functions of the complex and the role of Elongator dependent tRNA modification in human disease.
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9
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Protein Phosphatase Sit4 Affects Lipid Droplet Synthesis and Soraphen A Resistance Independent of Its Role in Regulating Elongator Dependent tRNA Modification. Biomolecules 2018; 8:biom8030049. [PMID: 29997346 PMCID: PMC6165401 DOI: 10.3390/biom8030049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 07/05/2018] [Accepted: 07/09/2018] [Indexed: 12/15/2022] Open
Abstract
The protein phosphatase Sit4 has been shown to be required for lipogenesis and resistance against the acetyl-CoA carboxylase inhibitor soraphen A. Since Sit4 is also required for biosynthesis of Elongator dependent tRNA modifications such as 5-methoxycarbonylmethyluridine (mcm5U), we investigated the relevance of tRNA modifications in lipogenesis and soraphen A response. While sit4 and Elongator (elp3) mutants copy defects in mcm5U formation and stress sensitivity, they do not share soraphen A sensitivity and low lipid droplet (LD) phenotypes. In contrast to sit4, we found elp3 mutants to display partial soraphen A resistance and a high LD phenotype. Screening a collection of tRNA modification mutants additionally identified the tRNA pseudo-uridine synthase gene DEG1 to be required for soraphen A sensitivity. Since deg1 and elp3 share high LD and soraphen A resistance phenotypes, these are likely caused by translational defects. In support of this notion, we observe overexpression of tRNAGlnUUG suppresses lipolysis defects of deg1 mutants. Hence, the sit4 mutation results in a composite defect including tRNA modification deficiency and loss of Snf1 kinase dephosphorylation, which induce opposite effects on LD regulation. Importantly, however, the Snf1 kinase regulatory defects of the phosphatase mutant dominate over effects on LD regulation imposed by loss of the tRNA modification alone.
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10
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Dalwadi U, Yip CK. Structural insights into the function of Elongator. Cell Mol Life Sci 2018; 75:1613-1622. [PMID: 29332244 PMCID: PMC11105301 DOI: 10.1007/s00018-018-2747-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 12/09/2017] [Accepted: 01/08/2018] [Indexed: 12/13/2022]
Abstract
Conserved from yeast to humans, Elongator is a protein complex implicated in multiple processes including transcription regulation, α-tubulin acetylation, and tRNA modification, and its defects have been shown to cause human diseases such as familial dysautonomia. Elongator consists of two copies of six core subunits (Elp1, Elp2, Elp3, Elp4, Elp5, and Elp6) that are organized into two subcomplexes: Elp1/2/3 and Elp4/5/6 and form a stable assembly of ~ 850 kDa in size. Although the catalytic subunit of Elongator is Elp3, which contains a radical S-adenosyl-L-methionine (SAM) domain and a putative histone acetyltransferase domain, the Elp4/5/6 subcomplex also possesses ATP-modulated tRNA binding activity. How at the molecular level, Elongator performs its multiple functions and how the different subunits regulate Elongator's activities remains poorly understood. Here, we provide an overview of the proposed functions of Elongator and describe how recent structural studies provide new insights into the mechanism of action of this multifunctional complex.
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Affiliation(s)
- Udit Dalwadi
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Calvin K Yip
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
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11
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Lu AX, Chong YT, Hsu IS, Strome B, Handfield LF, Kraus O, Andrews BJ, Moses AM. Integrating images from multiple microscopy screens reveals diverse patterns of change in the subcellular localization of proteins. eLife 2018; 7:e31872. [PMID: 29620521 PMCID: PMC5935485 DOI: 10.7554/elife.31872] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Accepted: 03/30/2018] [Indexed: 01/29/2023] Open
Abstract
The evaluation of protein localization changes on a systematic level is a powerful tool for understanding how cells respond to environmental, chemical, or genetic perturbations. To date, work in understanding these proteomic responses through high-throughput imaging has catalogued localization changes independently for each perturbation. To distinguish changes that are targeted responses to the specific perturbation or more generalized programs, we developed a scalable approach to visualize the localization behavior of proteins across multiple experiments as a quantitative pattern. By applying this approach to 24 experimental screens consisting of nearly 400,000 images, we differentiated specific responses from more generalized ones, discovered nuance in the localization behavior of stress-responsive proteins, and formed hypotheses by clustering proteins that have similar patterns. Previous approaches aim to capture all localization changes for a single screen as accurately as possible, whereas our work aims to integrate large amounts of imaging data to find unexpected new cell biology.
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Affiliation(s)
- Alex X Lu
- Department of Computer ScienceUniversity of TorontoTorontoCanada
| | - Yolanda T Chong
- Terrence Donnelly Centre for Cellular and Biomolecular ResearchUniversity of TorontoTorontoCanada
| | - Ian Shen Hsu
- Department of Cell and Systems BiologyUniversity of TorontoTorontoCanada
| | - Bob Strome
- Department of Cell and Systems BiologyUniversity of TorontoTorontoCanada
| | | | - Oren Kraus
- Department of Electrical and Computer EngineeringUniversity of TorontoTorontoCanada
| | - Brenda J Andrews
- Terrence Donnelly Centre for Cellular and Biomolecular ResearchUniversity of TorontoTorontoCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoCanada
| | - Alan M Moses
- Department of Computer ScienceUniversity of TorontoTorontoCanada
- Department of Cell and Systems BiologyUniversity of TorontoTorontoCanada
- Center for Analysis of Genome Evolution and FunctionUniversity of TorontoTorontoCanada
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12
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Wang C, Zhang X, Li J, Zhang Y, Mou Z. The Elongator complex-associated protein DRL1 plays a positive role in immune responses against necrotrophic fungal pathogens in Arabidopsis. MOLECULAR PLANT PATHOLOGY 2018; 19:286-299. [PMID: 27868335 PMCID: PMC6637984 DOI: 10.1111/mpp.12516] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 11/15/2016] [Accepted: 11/18/2016] [Indexed: 05/24/2023]
Abstract
DEFORMED ROOT AND LEAVES1 (DRL1) is an Arabidopsis homologue of the yeast TOXIN TARGET4 (TOT4)/KILLER TOXIN-INSENSITIVE12 (KTI12) protein that is physically associated with the RNA polymerase II-interacting protein complex named Elongator. Mutations in DRL1 and Elongator lead to similar morphological and molecular phenotypes, suggesting that DRL1 and Elongator may functionally overlap in Arabidopsis. We have shown previously that Elongator plays an important role in both salicylic acid (SA)- and jasmonic acid (JA)/ethylene (ET)-mediated defence responses. Here, we tested whether DRL1 also plays a similar role as Elongator in plant immune responses. Our results show that, although DRL1 partially contributes to SA-induced cytotoxicity, it does not play a significant role in SA-mediated expression of PATHOGENESIS-RELATED genes and resistance to the virulent bacterial pathogen Pseudomonas syringae pv. maculicola ES4326. In contrast, DRL1 is required for JA/ET- and necrotrophic fungal pathogen Botrytis cinerea-induced defence gene expression and for resistance to B. cinerea and Alternaria brassicicola. Furthermore, unlike the TOT4/KTI12 gene which, when overexpressed in yeast, confers zymocin resistance, a phenotype of the tot4/kti12 mutant, overexpression of DRL1 does not change B. cinerea-induced defence gene expression and resistance to this pathogen. Finally, DRL1 contains an N-terminal P-loop and a C-terminal calmodulin (CaM)-binding domain and is a CaM-binding protein. We demonstrate that both the P-loop and the CaM-binding domain are essential for the function of DRL1 in B. cinerea-induced expression of PDF1.2 and ORA59, and in resistance to B. cinerea, suggesting that the function of DRL1 in plant immunity may be regulated by ATP/GTP and CaM binding.
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Affiliation(s)
- Chenggang Wang
- Department of Microbiology and Cell ScienceUniversity of Florida, PO Box 110700GainesvilleFL32611USA
| | - Xudong Zhang
- Department of Microbiology and Cell ScienceUniversity of Florida, PO Box 110700GainesvilleFL32611USA
| | - Jian‐Liang Li
- Sanford Burnham Prebys Medical Discovery Institute at Lake NonaOrlandoFL32827USA
| | - Yanping Zhang
- Interdisciplinary Center for Biotechnology Research, University of Florida, PO Box 103622GainesvilleFL32610USA
| | - Zhonglin Mou
- Department of Microbiology and Cell ScienceUniversity of Florida, PO Box 110700GainesvilleFL32611USA
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13
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Wang Y, Pang C, Li X, Hu Z, Lv Z, Zheng B, Chen P. Identification of tRNA nucleoside modification genes critical for stress response and development in rice and Arabidopsis. BMC PLANT BIOLOGY 2017; 17:261. [PMID: 29268705 PMCID: PMC5740945 DOI: 10.1186/s12870-017-1206-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 12/06/2017] [Indexed: 05/20/2023]
Abstract
BACKGROUND Modification of nucleosides on transfer RNA (tRNA) is important either for correct mRNA decoding process or for tRNA structural stabilization. Nucleoside methylations catalyzed by MTase (methyltransferase) are the most common type among all tRNA nucleoside modifications. Although tRNA modified nucleosides and modification enzymes have been extensively studied in prokaryotic systems, similar research remains preliminary in higher plants, especially in crop species, such as rice (Oryza sativa). Rice is a monocot model plant as well as an important cereal crop, and stress tolerance and yield are of great importance for rice breeding. RESULTS In this study, we investigated how the composition and abundance of tRNA modified nucleosides could change in response to drought, salt and cold stress, as well as in different tissues during the whole growth season in two model plants-O. sativa and Arabidopsis thaliana. Twenty two and 20 MTase candidate genes were identified in rice and Arabidopsis, respectively, by protein sequence homology and conserved domain analysis. Four methylated nucleosides, Am, Cm, m1A and m7G, were found to be very important in stress response both in rice and Arabidopsis. Additionally, three nucleosides,Gm, m5U and m5C, were involved in plant development. Hierarchical clustering analysis revealed consistency on Am, Cm, m1A and m7G MTase candidate genes, and the abundance of the corresponding nucleoside under stress conditions. The same is true for Gm, m5U and m5C modifications and corresponding methylation genes in different tissues during different developmental stages. CONCLUSIONS We identified candidate genes for various tRNA modified nucleosides in rice and Arabidopsis, especially on MTases for methylated nucleosides. Based on bioinformatics analysis, nucleoside abundance assessments and gene expression profiling, we propose four methylated nucleosides (Am, Cm, m1A and m7G) that are critical for stress response in rice and Arabidopsis, and three methylated nucleosides (Gm, m5U and m5C) that might be important during development.
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Affiliation(s)
- Youmei Wang
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, 430070 China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070 China
| | - Chaoqun Pang
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, 430070 China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070 China
| | - Xukai Li
- College of Life Sciences, Shanxi Agricultural University, Taigu, Shanxi Province 030801 China
| | - Zhen Hu
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, 430070 China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070 China
| | - Zhengyi Lv
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, 430070 China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070 China
| | - Bo Zheng
- Key Laboratory of Horticultural Plant Biology of Ministry of Education, Huazhong Agricultural University, Wuhan, 430070 China
- College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070 China
| | - Peng Chen
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, 430070 China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070 China
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14
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Dauden MI, Jaciuk M, Müller CW, Glatt S. Structural asymmetry in the eukaryotic Elongator complex. FEBS Lett 2017; 592:502-515. [DOI: 10.1002/1873-3468.12865] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 09/08/2017] [Accepted: 09/24/2017] [Indexed: 12/28/2022]
Affiliation(s)
- Maria I. Dauden
- Structural and Computational Biology Unit European Molecular Biology Laboratory Heidelberg Germany
| | - Marcin Jaciuk
- Max Planck Research Group at the Malopolska Centre of Biotechnology Jagiellonian University Krakow Poland
| | - Christoph W. Müller
- Structural and Computational Biology Unit European Molecular Biology Laboratory Heidelberg Germany
| | - Sebastian Glatt
- Max Planck Research Group at the Malopolska Centre of Biotechnology Jagiellonian University Krakow Poland
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15
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Mehlgarten C, Prochaska H, Hammermeister A, Abdel-Fattah W, Wagner M, Krutyhołowa R, Jun SE, Kim GT, Glatt S, Breunig KD, Stark MJR, Schaffrath R. Use of a Yeast tRNase Killer Toxin to Diagnose Kti12 Motifs Required for tRNA Modification by Elongator. Toxins (Basel) 2017; 9:E272. [PMID: 28872616 PMCID: PMC5618205 DOI: 10.3390/toxins9090272] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 08/29/2017] [Accepted: 09/03/2017] [Indexed: 01/23/2023] Open
Abstract
Saccharomyces cerevisiae cells are killed by zymocin, a tRNase ribotoxin complex from Kluyveromyces lactis, which cleaves anticodons and inhibits protein synthesis. Zymocin's action requires specific chemical modification of uridine bases in the anticodon wobble position (U34) by the Elongator complex (Elp1-Elp6). Hence, loss of anticodon modification in mutants lacking Elongator or related KTI (K. lactis Toxin Insensitive) genes protects against tRNA cleavage and confers resistance to the toxin. Here, we show that zymocin can be used as a tool to genetically analyse KTI12, a gene previously shown to code for an Elongator partner protein. From a kti12 mutant pool of zymocin survivors, we identify motifs in Kti12 that are functionally directly coupled to Elongator activity. In addition, shared requirement of U34 modifications for nonsense and missense tRNA suppression (SUP4; SOE1) strongly suggests that Kti12 and Elongator cooperate to assure proper tRNA functioning. We show that the Kti12 motifs are conserved in plant ortholog DRL1/ELO4 from Arabidopsis thaliana and seem to be involved in binding of cofactors (e.g., nucleotides, calmodulin). Elongator interaction defects triggered by mutations in these motifs correlate with phenotypes typical for loss of U34 modification. Thus, tRNA modification by Elongator appears to require physical contact with Kti12, and our preliminary data suggest that metabolic signals may affect proper communication between them.
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Affiliation(s)
- Constance Mehlgarten
- Institut für Biologie, Martin Luther Universität Halle-Wittenberg, Weinbergweg 10, 06120 Halle/Saale, Germany.
| | - Heike Prochaska
- Institut für Biologie, Martin Luther Universität Halle-Wittenberg, Weinbergweg 10, 06120 Halle/Saale, Germany.
| | - Alexander Hammermeister
- Institut für Biologie, FG Mikrobiologie, Universität Kassel, Heirich-Plett-Str. 40, 34132 Kassel, Germany.
| | - Wael Abdel-Fattah
- Institut für Biologie, FG Mikrobiologie, Universität Kassel, Heirich-Plett-Str. 40, 34132 Kassel, Germany.
| | - Melanie Wagner
- Institut für Biologie, Martin Luther Universität Halle-Wittenberg, Weinbergweg 10, 06120 Halle/Saale, Germany.
| | - Rościsław Krutyhołowa
- Max Planck Research Group at the Malopolska Centre of Biotechnology, Jagiellonian University, 31-007 Krakow, Poland.
- Department of Cell Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 31-007 Krakow, Poland.
| | - Sang Eun Jun
- Department of Molecular Biotechnology, Dong-A University, Busan 604-714, Korea.
| | - Gyung-Tae Kim
- Department of Molecular Biotechnology, Dong-A University, Busan 604-714, Korea.
| | - Sebastian Glatt
- Max Planck Research Group at the Malopolska Centre of Biotechnology, Jagiellonian University, 31-007 Krakow, Poland.
| | - Karin D Breunig
- Institut für Biologie, Martin Luther Universität Halle-Wittenberg, Weinbergweg 10, 06120 Halle/Saale, Germany.
| | - Michael J R Stark
- Centre for Gene Regulation & Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
| | - Raffael Schaffrath
- Institut für Biologie, Martin Luther Universität Halle-Wittenberg, Weinbergweg 10, 06120 Halle/Saale, Germany.
- Institut für Biologie, FG Mikrobiologie, Universität Kassel, Heirich-Plett-Str. 40, 34132 Kassel, Germany.
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16
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Abstract
Wobble uridines (U34) are generally modified in all species. U34 modifications can be essential in metazoans but are not required for viability in fungi. In this review, we provide an overview on the types of modifications and how they affect the physico-chemical properties of wobble uridines. We describe the molecular machinery required to introduce these modifications into tRNA posttranscriptionally and discuss how posttranslational regulation may affect the activity of the modifying enzymes. We highlight the activity of anticodon specific RNases that target U34 containing tRNA. Finally, we discuss how defects in wobble uridine modifications lead to phenotypes in different species. Importantly, this review will mainly focus on the cytoplasmic tRNAs of eukaryotes. A recent review has extensively covered their bacterial and mitochondrial counterparts.1
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Affiliation(s)
- Raffael Schaffrath
- a Institut für Biologie, FG Mikrobiologie , Universität Kassel , Germany
| | - Sebastian A Leidel
- b Max Planck Institute for Molecular Biomedicine , Germany.,c Cells-in-Motion Cluster of Excellence , University of Münster , Münster , Germany.,d Medical Faculty , University of Münster , Albert-Schweitzer-Campus 1, Münster , Germany
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17
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Kolaj-Robin O, Séraphin B. Structures and Activities of the Elongator Complex and Its Cofactors. RNA MODIFICATION 2017; 41:117-149. [DOI: 10.1016/bs.enz.2017.03.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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18
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Karlsborn T, Tükenmez H, Mahmud AKMF, Xu F, Xu H, Byström AS. Elongator, a conserved complex required for wobble uridine modifications in eukaryotes. RNA Biol 2015; 11:1519-28. [PMID: 25607684 DOI: 10.4161/15476286.2014.992276] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Elongator is a 6 subunit protein complex highly conserved in eukaryotes. The role of this complex has been controversial as the pleiotropic phenotypes of Elongator mutants have implicated the complex in several cellular processes. However, in yeast there is convincing evidence that the primary and probably only role of this complex is in formation of the 5-methoxycarbonylmethyl (mcm(5)) and 5-carbamoylmethyl (ncm(5)) side chains on uridines at wobble position in tRNA. In this review we summarize the cellular processes that have been linked to the Elongator complex and discuss its role in tRNA modification and regulation of translation. We also describe additional gene products essential for formation of ncm(5) and mcm(5) side chains at U34 and their influence on Elongator activity.
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Affiliation(s)
- Tony Karlsborn
- a Department of Molecular Biology ; Umeå University; Umeå , Sweden
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19
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Ghalei H, Schaub FX, Doherty JR, Noguchi Y, Roush WR, Cleveland JL, Stroupe ME, Karbstein K. Hrr25/CK1δ-directed release of Ltv1 from pre-40S ribosomes is necessary for ribosome assembly and cell growth. J Cell Biol 2015; 208:745-59. [PMID: 25778921 PMCID: PMC4362465 DOI: 10.1083/jcb.201409056] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 02/02/2015] [Indexed: 11/25/2022] Open
Abstract
Casein kinase 1δ/ε (CK1δ/ε) and their yeast homologue Hrr25 are essential for cell growth. Further, CK1δ is overexpressed in several malignancies, and CK1δ inhibitors have shown promise in several preclinical animal studies. However, the substrates of Hrr25 and CK1δ/ε that are necessary for cell growth and survival are unknown. We show that Hrr25 is essential for ribosome assembly, where it phosphorylates the assembly factor Ltv1, which causes its release from nascent 40S subunits and allows subunit maturation. Hrr25 inactivation or expression of a nonphosphorylatable Ltv1 variant blocked Ltv1 release in vitro and in vivo, and prevented entry into the translation-like quality control cycle. Conversely, phosphomimetic Ltv1 variants rescued viability after Hrr25 depletion. Finally, Ltv1 knockdown in human breast cancer cells impaired apoptosis induced by CK1δ/ε inhibitors, establishing that the antiproliferative activity of these inhibitors is due, at least in part, to disruption of ribosome assembly. These findings validate the ribosome assembly pathway as a novel target for the development of anticancer therapeutics.
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Affiliation(s)
- Homa Ghalei
- Department of Cancer Biology and Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458
| | - Franz X Schaub
- Department of Cancer Biology and Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458 Department of Tumor Biology, Moffitt Cancer and Research Institute, Tampa, FL 33612
| | - Joanne R Doherty
- Department of Cancer Biology and Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458
| | - Yoshihiko Noguchi
- Department of Cancer Biology and Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458
| | - William R Roush
- Department of Cancer Biology and Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458
| | - John L Cleveland
- Department of Cancer Biology and Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458 Department of Tumor Biology, Moffitt Cancer and Research Institute, Tampa, FL 33612
| | - M Elizabeth Stroupe
- Department of Biological Science and Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306 Department of Biological Science and Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306
| | - Katrin Karbstein
- Department of Cancer Biology and Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458
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20
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Jun SE, Cho KH, Hwang JY, Abdel-Fattah W, Hammermeister A, Schaffrath R, Bowman JL, Kim GT. Comparative analysis of the conserved functions of Arabidopsis DRL1 and yeast KTI12. Mol Cells 2015; 38:243-50. [PMID: 25518926 PMCID: PMC4363724 DOI: 10.14348/molcells.2015.2297] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 12/03/2014] [Accepted: 12/03/2014] [Indexed: 12/18/2022] Open
Abstract
Patterning of the polar axis during the early leaf developmental stage is established by cell-to-cell communication between the shoot apical meristem (SAM) and the leaf primordia. In a previous study, we showed that the DRL1 gene, which encodes a homolog of the Elongator-associated protein KTI12 of yeast, acts as a positive regulator of adaxial leaf patterning and shoot meristem activity. To determine the evolutionally conserved functions of DRL1, we performed a comparison of the deduced amino acid sequence of DRL1 and its yeast homolog, KTI12, and found that while overall homology was low, well-conserved domains were presented. DRL1 contained two conserved plant-specific domains. Expression of the DRL1 gene in a yeast KTI12-deficient yeast mutant suppressed the growth retardation phenotype, but did not rescue the caffeine sensitivity, indicating that the role of Arabidopsis Elongator-associated protein is partially conserved with yeast KTI12, but may have changed between yeast and plants in response to caffeine during the course of evolution. In addition, elevated expression of DRL1 gene triggered zymocin sensitivity, while overexpression of KTI12 maintained zymocin resistance, indicating that the function of Arabidopsis DRL1 may not overlap with yeast KTI12 with regards to toxin sensitivity. In this study, expression analysis showed that class-I KNOX genes were downregulated in the shoot apex, and that YAB and KAN were upregulated in leaves of the Arabidopsis drl1-101 mutant. Our results provide insight into the communication network between the SAM and leaf primordia required for the establishment of leaf polarity by mediating histone acetylation or through other mechanisms.
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Affiliation(s)
- Sang Eun Jun
- Department of Molecular Biotechnology, Dong-A University, Busan 604-714,
Korea
| | - Kiu-Hyung Cho
- Department of Molecular Biotechnology, Dong-A University, Busan 604-714,
Korea
| | - Ji-Young Hwang
- Department of Molecular Biotechnology, Dong-A University, Busan 604-714,
Korea
| | - Wael Abdel-Fattah
- Institut für Biologie, FG Mikrobiologie, Universität Kassel,
Germany
| | | | - Raffael Schaffrath
- Department of Genetics, University of Leicester,
UK
- Institut für Biologie, FG Mikrobiologie, Universität Kassel,
Germany
| | - John L. Bowman
- School of Biological Sciences, Monash University, Melbourne,
Australia
| | - Gyung-Tae Kim
- Department of Molecular Biotechnology, Dong-A University, Busan 604-714,
Korea
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21
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Kolaj-Robin O, McEwen AG, Cavarelli J, Séraphin B. Structure of the Elongator cofactor complex Kti11/Kti13 provides insight into the role of Kti13 in Elongator-dependent tRNA modification. FEBS J 2015; 282:819-33. [PMID: 25604895 DOI: 10.1111/febs.13199] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 01/12/2015] [Accepted: 01/14/2015] [Indexed: 12/26/2022]
Abstract
UNLABELLED Modification of wobble uridines of many eukaryotic tRNAs requires the Elongator complex, a highly conserved six-subunit eukaryotic protein assembly, as well as the Killer toxin-insensitive (Kti) proteins 11-14. Kti11 was additionally shown to be implicated in the biosynthesis of diphthamide, a post-translationally modified histidine of translation elongation factor 2. Recent data indicate that iron-bearing Kti11 functions as an electron donor to the [4Fe-4S] cluster of radical S-Adenosylmethionine enzymes, triggering the subsequent radical reaction. We show here that recombinant yeast Kti11 forms a stable 1 : 1 complex with Kti13. To obtain insights into the function of this heterodimer, the Kti11/Kti13 complex was purified to homogeneity, crystallized, and its structure determined at 1.45 Å resolution. The importance of several residues mediating complex formation was confirmed by mutagenesis. Kti13 adopts a fold characteristic of RCC1-like proteins. The seven-bladed β-propeller consists of a unique mixture of four- and three-stranded blades. In the complex, Kti13 orients Kti11 and restricts access to its electron-carrying iron atom, constraining the electron transfer capacity of Kti11. Based on these findings, we propose a role for Kti13, and discuss the possible functional implications of complex formation. DATABASE Structural data have been submitted to the Protein Data Bank under accession number 4X33.
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Affiliation(s)
- Olga Kolaj-Robin
- Equipe Labellisée La Ligue, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Centre National de Recherche Scientifique UMR 7104/Institut National de Santé et de Recherche Médicale U964/Université de Strasbourg, Illkirch, France
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22
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Abdel-Fattah W, Jablonowski D, Di Santo R, Thüring KL, Scheidt V, Hammermeister A, ten Have S, Helm M, Schaffrath R, Stark MJR. Phosphorylation of Elp1 by Hrr25 is required for elongator-dependent tRNA modification in yeast. PLoS Genet 2015; 11:e1004931. [PMID: 25569479 PMCID: PMC4287497 DOI: 10.1371/journal.pgen.1004931] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 12/01/2014] [Indexed: 12/26/2022] Open
Abstract
Elongator is a conserved protein complex comprising six different polypeptides that has been ascribed a wide range of functions, but which is now known to be required for modification of uridine residues in the wobble position of a subset of tRNAs in yeast, plants, worms and mammals. In previous work, we showed that Elongator's largest subunit (Elp1; also known as Iki3) was phosphorylated and implicated the yeast casein kinase I Hrr25 in Elongator function. Here we report identification of nine in vivo phosphorylation sites within Elp1 and show that four of these, clustered close to the Elp1 C-terminus and adjacent to a region that binds tRNA, are important for Elongator's tRNA modification function. Hrr25 protein kinase directly modifies Elp1 on two sites (Ser-1198 and Ser-1202) and through analyzing non-phosphorylatable (alanine) and acidic, phosphomimic substitutions at Ser-1198, Ser-1202 and Ser-1209, we provide evidence that phosphorylation plays a positive role in the tRNA modification function of Elongator and may regulate the interaction of Elongator both with its accessory protein Kti12 and with Hrr25 kinase. tRNA molecules function as adapters in protein synthesis, bringing amino acids to the ribosome and reading the genetic code through codon-anticodon base pairing. When the tRNA contains a uridine residue in the “wobble position” of its anticodon, which base-pairs with purine residues in the third position of a cognate codon, it is almost always chemically modified and modification is required for efficient decoding. In eukaryotic cells, these wobble uridine modifications require a conserved protein complex called Elongator. Our work shows that Elp1, Elongator's largest subunit, is phosphorylated on several sites. By blocking phosphorylation at these positions using mutations, we identified four phosphorylation sites that are important for Elongator's role in tRNA modification. We have also shown that Hrr25 protein kinase, a member of the casein kinase I (CKI) family, is responsible for modification of two of the sites that are important for Elongator function. Phosphorylation appears to affect interaction of the Elongator complex both with its kinase (Hrr25) and with Kti12, an accessory protein previously implicated in Elongator function. Our studies imply that Elp1 phosphorylation plays a positive role in Elongator-mediated tRNA modification and raise the possibility that wobble uridine modification may be regulated, representing a potential translational control mechanism.
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Affiliation(s)
- Wael Abdel-Fattah
- Centre for Gene Regulation & Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom
- Institut für Biologie, FG Mikrobiologie, Universität Kassel, Germany
| | | | - Rachael Di Santo
- Centre for Gene Regulation & Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Kathrin L. Thüring
- Institut für Pharmazie und Biochemie, Johannes Gutenberg-Universität Mainz, Germany
| | - Viktor Scheidt
- Institut für Biologie, FG Mikrobiologie, Universität Kassel, Germany
| | | | - Sara ten Have
- Centre for Gene Regulation & Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Mark Helm
- Institut für Pharmazie und Biochemie, Johannes Gutenberg-Universität Mainz, Germany
| | - Raffael Schaffrath
- Institut für Biologie, FG Mikrobiologie, Universität Kassel, Germany
- Department of Genetics, University of Leicester, Leicester, United Kingdom
- * E-mail: (RS); (MJRS)
| | - Michael J. R. Stark
- Centre for Gene Regulation & Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom
- * E-mail: (RS); (MJRS)
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23
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Glatt S, Zabel R, Vonkova I, Kumar A, Netz DJ, Pierik AJ, Rybin V, Lill R, Gavin AC, Balbach J, Breunig KD, Müller CW. Structure of the Kti11/Kti13 heterodimer and its double role in modifications of tRNA and eukaryotic elongation factor 2. Structure 2014; 23:149-160. [PMID: 25543256 DOI: 10.1016/j.str.2014.11.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 11/11/2014] [Accepted: 11/13/2014] [Indexed: 12/14/2022]
Abstract
The small, highly conserved Kti11 alias Dph3 protein encoded by the Kluyveromyces lactis killer toxin insensitive gene KTI11/DPH3 is involved in the diphthamide modification of eukaryotic elongation factor 2 and, together with Kti13, in Elongator-dependent tRNA wobble base modifications, thereby affecting the speed and accuracy of protein biosynthesis through two distinct mechanisms. We have solved the crystal structures of Saccharomyces cerevisiae Kti13 and the Kti11/Kti13 heterodimer at 2.4 and 2.9 Å resolution, respectively, and validated interacting residues through mutational analysis in vitro and in vivo. We show that metal coordination by Kti11 and its heterodimerization with Kti13 are essential for both translational control mechanisms. Our structural and functional analyses identify Kti13 as an additional component of the diphthamide modification pathway and provide insight into the molecular mechanisms that allow the Kti11/Kti13 heterodimer to coregulate two consecutive steps in ribosomal protein synthesis.
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Affiliation(s)
- Sebastian Glatt
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Rene Zabel
- Martin-Luther-Universität Halle-Wittenberg, Institut für Biologie, Weinbergweg 10, 06120 Halle (Saale), Germany
| | - Ivana Vonkova
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Amit Kumar
- Martin-Luther-Universität Halle-Wittenberg, Institut für Physik, Betty-Heimann-Straße 7, 06120 Halle (Saale), Germany
| | - Daili J Netz
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Straße 6, 35037 Marburg, Germany
| | - Antonio J Pierik
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Straße 6, 35037 Marburg, Germany
| | - Vladimir Rybin
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Roland Lill
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Straße 6, 35037 Marburg, Germany; LOEWE Zentrum für Synthetische Mikrobiologie SynMikro, Hans-Meerwein-Straße, 35043 Marburg, Germany
| | - Anne-Claude Gavin
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Jochen Balbach
- Martin-Luther-Universität Halle-Wittenberg, Institut für Physik, Betty-Heimann-Straße 7, 06120 Halle (Saale), Germany
| | - Karin D Breunig
- Martin-Luther-Universität Halle-Wittenberg, Institut für Biologie, Weinbergweg 10, 06120 Halle (Saale), Germany.
| | - Christoph W Müller
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany.
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24
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Schaffrath R, Abdel-Fattah W, Klassen R, Stark MJR. The diphthamide modification pathway from Saccharomyces cerevisiae--revisited. Mol Microbiol 2014; 94:1213-26. [PMID: 25352115 DOI: 10.1111/mmi.12845] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2014] [Indexed: 01/09/2023]
Abstract
Diphthamide is a conserved modification in archaeal and eukaryal translation elongation factor 2 (EF2). Its name refers to the target function for diphtheria toxin, the disease-causing agent that, through ADP ribosylation of diphthamide, causes irreversible inactivation of EF2 and cell death. Although this clearly emphasizes a pathobiological role for diphthamide, its physiological function is unclear, and precisely why cells need EF2 to contain diphthamide is hardly understood. Nonetheless, the conservation of diphthamide biosynthesis together with syndromes (i.e. ribosomal frame-shifting, embryonic lethality, neurodegeneration and cancer) typical of mutant cells that cannot make it strongly suggests that diphthamide-modified EF2 occupies an important and translation-related role in cell proliferation and development. Whether this is structural and/or regulatory remains to be seen. However, recent progress in dissecting the diphthamide gene network (DPH1-DPH7) from the budding yeast Saccharomyces cerevisiae has significantly advanced our understanding of the mechanisms required to initiate and complete diphthamide synthesis on EF2. Here, we review recent developments in the field that not only have provided novel, previously overlooked and unexpected insights into the pathway and the biochemical players required for diphthamide synthesis but also are likely to foster innovative studies into the potential regulation of diphthamide, and importantly, its ill-defined biological role.
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Affiliation(s)
- Raffael Schaffrath
- Department of Genetics, University of Leicester, Leicester, LE1 7RH, UK; Institut für Biologie, Abteilung Mikrobiologie, Universität Kassel, 34132, Kassel, Germany
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25
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Di Santo R, Bandau S, Stark MJR. A conserved and essential basic region mediates tRNA binding to the Elp1 subunit of the Saccharomyces cerevisiae Elongator complex. Mol Microbiol 2014; 92:1227-42. [PMID: 24750273 PMCID: PMC4150532 DOI: 10.1111/mmi.12624] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2014] [Indexed: 12/25/2022]
Abstract
Elongator is a conserved, multi-protein complex discovered in Saccharomyces cerevisiae, loss of which confers a range of pleiotropic phenotypes. Elongator in higher eukaryotes is required for normal growth and development and a mutation in the largest subunit of human Elongator (Elp1) causes familial dysautonomia, a severe recessive neuropathy. Elongator promotes addition of mcm(5) and ncm(5) modifications to uridine in the tRNA anticodon 'wobble' position in both yeast and higher eukaryotes. Since these modifications are required for the tRNAs to function efficiently, a translation defect caused by hypomodified tRNAs may therefore underlie the variety of phenotypes associated with Elongator dysfunction. The Elp1 carboxy-terminal domain contains a highly conserved arginine/lysine-rich region that resembles a nuclear localization sequence (NLS). Using alanine substitution mutagenesis, we show that this region is essential for Elongator's function in tRNA wobble uridine modification. However, rather than acting to determine the nucleo-cytoplasmic distribution of Elongator, we find that the basic region plays a critical role in a novel interaction between tRNA and the Elp1 carboxy-terminal domain. Thus the conserved basic region in Elp1 may be essential for tRNA wobble uridine modification by acting as tRNA binding motif.
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Affiliation(s)
- Rachael Di Santo
- Centre for Gene Regulation & Expression, College of Life Sciences, MSI/WTB Complex, University of DundeeDundee, DD1 5EH, Scotland, UK
| | | | - Michael J R Stark
- Centre for Gene Regulation & Expression, College of Life Sciences, MSI/WTB Complex, University of DundeeDundee, DD1 5EH, Scotland, UK
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26
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A novel Sit4 phosphatase complex is involved in the response to ceramide stress in yeast. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:129645. [PMID: 24082981 PMCID: PMC3777123 DOI: 10.1155/2013/129645] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 06/28/2013] [Accepted: 07/25/2013] [Indexed: 12/17/2022]
Abstract
Ceramide is a building block for complex sphingolipids in the plasma membrane, but it also plays a significant role in secondary signalling pathways regulating cell proliferation and apoptosis in response to stress. Ceramide activated protein phosphatase activity has been previously observed in association with the Sit4 protein phosphatase. Here we find that sit4Δ mutants have decreased ceramide levels and display resistance to exogenous ceramides and phytosphingosine. Mutants lacking SIT4 or KTI12 display a shift towards nonhydroxylated forms of long chain bases and sphingolipids, suggesting regulation of hydroxylase (SUR2) or ceramide synthase by Sit4p. We have identified novel subunits of the Sit4 complex and have also shown that known Sit4 regulatory subunits—SAP proteins—are not involved in the ceramide response. This is the first observation of separation of function between Sit4 and SAP proteins. We also find that the Sit4p target Elongator is not involved in the ceramide response but that cells deficient in Kti12p—an accessory protein with an undefined regulatory role—have similar ceramide phenotypes to sit4Δ mutants. Therefore, Kti12p may play a similar secondary role in the ceramide response. This evidence points to a novel Sit4-dependent regulatory mechanism in response to ceramide stress.
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27
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Structural insights into Elongator function. Curr Opin Struct Biol 2013; 23:235-42. [PMID: 23510783 DOI: 10.1016/j.sbi.2013.02.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 02/26/2013] [Indexed: 11/20/2022]
Abstract
The eukaryotic Elongator complex was initially identified in yeast as a RNA polymerase II (Pol II) associated transcription elongation factor, although there is accumulating evidence that its main cellular function is the specific modification of uridines at the wobble base position of tRNAs. Elongator complex is built up by six highly conserved subunits and was shown to be involved in a variety of different cellular activities. Here, we summarize structural and functional information on individual Elongator subunits or subcomplexes. On the basis of homology models of the Elp1, Elp2 and Elp3 subunits and the crystal structure of the Elp456 subcomplex, the role of each subunit in Elongator complex assembly and catalytic activity is discussed.
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28
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Santos A, Alonso A, Belda I, Marquina D. Cell cycle arrest and apoptosis, two alternative mechanisms for PMKT2 killer activity. Fungal Genet Biol 2012; 50:44-54. [PMID: 23137543 DOI: 10.1016/j.fgb.2012.10.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 10/12/2012] [Accepted: 10/25/2012] [Indexed: 10/27/2022]
Abstract
Pichia membranifaciens CYC 1086 secretes a unique 30kDa killer toxin (PMKT2) that inhibits a variety of spoilage yeasts and fungi of agronomical interest. The cytocidal effect of PMKT2 on Saccharomyces cerevisiae cells was studied. Metabolic events associated with the loss of S. cerevisiae viability caused by PMKT2 were qualitatively identical to those reported for K28 killer toxin activity, but different to those reported for PMKT. At higher doses, none of the cellular events accounting for the action of PMKT, the killer toxin secreted by P. membranifaciens CYC 1106, was observed for PMKT2. Potassium leakage, sodium influx and the decrease of intracellular pH were not among the primary effects of PMKT2. We report here that this protein is unable to form ion-permeable channels in liposome membranes, suggesting that channel formation is not the mechanism of cytotoxic action of PMKT2. Nevertheless, flow cytometry studies have revealed a cell cycle arrest at an early S-phase with an immature bud and pre-replicated 1n DNA content. By testing the sensitivity of cells arrested at different stages in the cell cycle, we hoped to identify the execution point for lethality more precisely. Cells arrested at the G1-phase by α-factor or arrested at G2-phase by the spindle poison methyl benzimidazol-2-yl-carbamate (MBC) were protected against the toxin. Cells released from the arrest in both cases were killed by PMKT2 at a similar rate. Nevertheless, cells released from MBC-arrest were able to grow for a short time, and then viability dropped rapidly. These findings suggest that cells released from G2-phase are initially able to divide, but die in the presence of PMKT2 after initiating the S-phase in a new cycle, adopting a terminal phenotype within that cycle. By contrast, low doses of PMKT and PMKT2 were able to generate the same cellular response. The evidence presented here shows that treating yeast with low doses of PMKT2 leads to the typical membranous, cytoplasmic, mitochondrial and nuclear markers of apoptosis, namely, the production of reactive oxygen species, DNA strand breaks, metacaspase activation and cytochrome c release.
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Affiliation(s)
- Antonio Santos
- Department of Microbiology, Complutense University of Madrid, Madrid, Spain
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29
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Satwika D, Klassen R, Meinhardt F. Anticodon nuclease encoding virus-like elements in yeast. Appl Microbiol Biotechnol 2012; 96:345-56. [PMID: 22899498 DOI: 10.1007/s00253-012-4349-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 07/31/2012] [Accepted: 08/01/2012] [Indexed: 11/29/2022]
Abstract
A variety of yeast species are known to host systems of cytoplasmic linear dsDNA molecules that establish replication and transcription independent of the nucleus via self-encoded enzymes that are phylogenetically related to those encoded by true infective viruses. Such yeast virus-like elements (VLE) fall into two categories: autonomous VLEs encode all the essential functions for their inheritance, and additional, dependent VLEs, which may encode a toxin-antitoxin system, generally referred to as killer toxin and immunity. In the two cases studied in depth, killer toxin action relies on chitin binding and hydrophobic domains, together allowing a separate toxic subunit to sneak into the target cell. Mechanistically, the latter sabotages codon-anticodon interaction by endonucleolytic cleavage of specific tRNAs 3' of the wobble nucleotide. This primary action provokes a number of downstream effects, including DNA damage accumulation, which contribute to the cell-killing efficiency and highlight the importance of proper transcript decoding capacity for other cellular processes than translation itself. Since wobble uridine modifications are crucial for efficient anticodon nuclease (ACNase) action of yeast killer toxins, the latter are valuable tools for the characterization of a surprisingly complex network regulating the addition of wobble base modifications in tRNA.
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Affiliation(s)
- Dhira Satwika
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Corrensstr. 3, 48149, Münster, Germany
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30
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Zhabokritsky A, Kutky M, Burns LA, Karran RA, Hudak KA. RNA toxins: mediators of stress adaptation and pathogen defense. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 2:890-903. [PMID: 21809449 DOI: 10.1002/wrna.99] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
RNA toxins are a group of enzymes primarily synthesized by bacteria, fungi, and plants that either cleave or depurinate RNA molecules. These proteins may be divided according to their RNA substrates: ribotoxins are nucleases that cleave ribosomal RNA (rRNA), ribosome inactivating proteins are glycosidases that remove a base from rRNA, messenger RNA (mRNA) interferases are nucleases that cleave mRNAs, and anticodon nucleases cleave transfer RNAs (tRNAs). These modifications to the RNAs may substantially alter gene expression and translation rates. Given that some of these enzymes cause cell death, it has been suggested that they function mainly in defense, either to kill competing cells or to elicit suicide and thereby limit pathogen spread from infected cells. Although good correlations have been drawn between their enzymatic functions and toxicity, recent work has shown that some RNA toxins cause apoptosis in the absence of damage to RNA and that defense against pathogens can be achieved without host cell death. Moreover, a decrease in cellular translation rate, insufficient to cause cell death, allows some organisms to adapt to stress and environmental change. Although ascribing effects observed in vitro to the roles of these toxins in nature has been challenging, recent results have expanded our understanding of their modes of action, and emphasized the importance of these toxins in development, adaptation to stress and defense against pathogens.
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Jain R, Poulos MG, Gros J, Chakravarty AK, Shuman S. Substrate specificity and mutational analysis of Kluyveromyces lactis gamma-toxin, a eukaryal tRNA anticodon nuclease. RNA (NEW YORK, N.Y.) 2011; 17:1336-43. [PMID: 21610213 PMCID: PMC3138569 DOI: 10.1261/rna.2722711] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 04/11/2011] [Indexed: 05/30/2023]
Abstract
tRNA anticodon damage inflicted by the Kluyveromyces lactis γ-toxin underlies an RNA-based innate immune system that distinguishes self from nonself species. γ-toxin arrests the growth of Saccharomyces cerevisiae by incising a single phosphodiester 3' of the wobble base of tRNA(Glu(UUC)) to generate a break with 2',3'-cyclic phosphate and 5'-OH ends. Recombinant γ-toxin cleaves oligonucleotide substrates in vitro that mimic the anticodon stem-loop of tRNA(Glu). A single 2'-deoxy sugar substitution at the wobble nucleoside abolishes anticodon nuclease activity. To gain further insights to γ-toxin's substrate specificity, we tested deoxynucleoside effects at positions other than the site of transesterification. The results attest to a stringent requirement for a ribonucleoside at the uridine 5' of the wobble base. In contrast, every other nonwobble ribonucleoside in the anticodon loop can be replaced by a deoxy without significantly affecting γ-toxin's cleavage activity. Whereas either the 5' half or the 3' half of the anticodon stem can be replaced en bloc with DNA without a major effect, simultaneously replacing both strands with DNA interfered strongly, signifying that γ-toxin requires an A-form helical conformation of the anticodon stem. We purified γ-toxin mutants identified previously as nontoxic in vivo and gauged their anticodon nuclease activities in vitro. The results highlight Glu9 and Arg151 as candidate catalytic residues, along with His209 implicated previously. By analogy to other endoribonucleases, we speculate that γ-toxin drives transesterification by general acid-base catalysis (via His209 and Glu9) and transition-state stabilization (via Arg151).
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Affiliation(s)
- Ruchi Jain
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA.
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32
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Genome-wide identification of genes that play a role in boron stress response in yeast. Genomics 2011; 97:106-11. [DOI: 10.1016/j.ygeno.2010.10.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2010] [Revised: 10/21/2010] [Accepted: 10/22/2010] [Indexed: 11/21/2022]
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33
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Shigematsu M, Ogawa T, Kido A, Kitamoto HK, Hidaka M, Masaki H. Cellular and transcriptional responses of yeast to the cleavage of cytosolic tRNAs induced by colicin D. Yeast 2009; 26:663-73. [PMID: 19877125 DOI: 10.1002/yea.1725] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
MESH Headings
- Base Sequence
- Cell Proliferation
- Cytosol/metabolism
- Escherichia coli Proteins/chemistry
- Escherichia coli Proteins/genetics
- Escherichia coli Proteins/metabolism
- Nucleic Acid Conformation
- Oligonucleotide Array Sequence Analysis
- Peptide Fragments/chemistry
- Peptide Fragments/genetics
- Peptide Fragments/metabolism
- Pheromones/metabolism
- Plasmids/genetics
- Protein Structure, Tertiary
- RNA, Bacterial/chemistry
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Fungal/chemistry
- RNA, Fungal/genetics
- RNA, Fungal/metabolism
- RNA, Transfer/chemistry
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- RNA, Transfer, Arg/chemistry
- RNA, Transfer, Arg/genetics
- RNA, Transfer, Arg/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/growth & development
- Saccharomyces cerevisiae/metabolism
- Saccharomyces cerevisiae Proteins/metabolism
- Signal Transduction
- Transcription, Genetic
- Transformation, Genetic
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Affiliation(s)
- Megumi Shigematsu
- Department of Biotechnology, University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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34
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Mehlgarten C, Jablonowski D, Breunig KD, Stark MJR, Schaffrath R. Elongator function depends on antagonistic regulation by casein kinase Hrr25 and protein phosphatase Sit4. Mol Microbiol 2009; 73:869-81. [PMID: 19656297 DOI: 10.1111/j.1365-2958.2009.06811.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In yeast, the role for the Elongator complex in tRNA anticodon modification is affected by phosphorylation of Elongator subunit Elp1. Thus, hyperphosphorylation of Elp1 due to inactivation of protein phosphatase Sit4 correlates with Elongator-minus phenotypes including resistance towards zymocin, a tRNase cleaving anticodons of Elongator-dependent tRNAs. Here we show that zymocin resistance of casein kinase hrr25 mutants associates with hypophosphorylation of Elp1 and that nonsense suppression by the Elongator-dependent SUP4 tRNA is abolished in hrr25 or sit4 mutants. Thus changes that perturb the evenly balanced ratio between hyper- and hypophosphorylated Elp1 forms present in wild-type cells lead to Elongator inactivation. Antagonistic roles for Hrr25 and Sit4 in Elongator function are further supported by our data that Sit4 inactivation is capable of restoring both zymocin sensitivity and normal ratios between the two Elp1 forms in hrr25 mutants. Hrr25 binds to Elongator in a fashion dependent on Elongator partner Kti12. Like sit4 mutants, overexpression of Kti12 triggers Elp1 hyperphosphorylation. Intriguingly, this effect of Kti12 is blocked by hrr25 mutations, which also show enhanced binding of Kti12 to Elongator. Collectively, our data suggest that rather than directly targeting Elp1, the Hrr25 kinase indirectly affects Elp1 phosphorylation states through control of Sit4-dependent dephosphorylation of Elp1.
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Affiliation(s)
- Constance Mehlgarten
- Institut für Biologie, Genetik, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
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35
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Huang B, Lu J, Byström AS. A genome-wide screen identifies genes required for formation of the wobble nucleoside 5-methoxycarbonylmethyl-2-thiouridine in Saccharomyces cerevisiae. RNA (NEW YORK, N.Y.) 2008; 14:2183-94. [PMID: 18755837 PMCID: PMC2553728 DOI: 10.1261/rna.1184108] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We recently showed that the gamma-subunit of Kluyveromyces lactis killer toxin (gamma-toxin) is a tRNA endonuclease that cleaves tRNA(mcm5s2UUC Glu), tRNA(mcm5s2UUU Lys), and tRNA(mcm5s2UUG Gln) 3' of the wobble nucleoside 5-methoxycarbonylmethyl-2-thiouridine (mcm(5)s(2)U). The 5-methoxycarbonylmethyl (mcm(5)) side chain was important for efficient cleavage by gamma-toxin, and defects in mcm(5) side-chain synthesis correlated with resistance to gamma-toxin. Based on this correlation, a genome-wide screen was performed to identify gene products involved in the formation of the mcm(5) side chain. From a collection of 4826 homozygous diploid Saccharomyces cerevisiae strains, each with one nonessential gene deleted, 63 mutants resistant to Kluyveromyces lactis killer toxin were identified. Among these, eight were earlier identified to have a defect in formation of the mcm(5) side chain. Analysis of the remaining mutants and other known gamma-toxin resistant mutants revealed that sit4, kti14, and KTI5 mutants also have a defect in the formation of mcm(5). A mutant lacking two of the Sit4-associated proteins, Sap185 and Sap190, displays the same modification defect as a sit4-null mutant. Interestingly, several mutants were found to be defective in the synthesis of the 2-thio (s(2)) group of the mcm(5)s(2)U nucleoside. In addition to earlier described mutants, formation of the s(2) group was also abolished in urm1, uba4, and ncs2 mutants and decreased in the yor251c mutant. Like the absence of the mcm(5) side chain, the lack of the s(2) group renders tRNA(mcm5s2UUC Glu) less sensitive to gamma-toxin, reinforcing the importance of the wobble nucleoside mcm(5)s(2)U for tRNA cleavage by gamma-toxin.
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Affiliation(s)
- Bo Huang
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden
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36
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Studte P, Zink S, Jablonowski D, Bär C, von der Haar T, Tuite MF, Schaffrath R. tRNA and protein methylase complexes mediate zymocin toxicity in yeast. Mol Microbiol 2008; 69:1266-77. [PMID: 18657261 DOI: 10.1111/j.1365-2958.2008.06358.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Modification of Saccharomyces cerevisiae tRNA anticodons at the wobble uridine (U34) position is required for tRNA cleavage by the zymocin tRNase killer toxin from Kluyveromyces lactis. Hence, U34 modification defects including lack of the U34 tRNA methyltransferase Trm9 protect against tRNA cleavage and zymocin. Using zymocin as a tool, we have identified toxin-resistant mutations in TRM9 that are likely to affect the U34 methylation reaction. Most strikingly, C-terminal truncations in Trm9 abolish interaction with Trm112, a protein shown to individually purify with Lys9 and two more methylases, Trm11 and Mtq2. Downregulation of a GAL1-TRM112 allele protects against zymocin whereas LYS9, TRM11 and MTQ2 are dosage suppressors of zymocin. Based on immune precipitation studies, the latter scenario correlates with competition for Trm112 and in excess, some of these Trm112 partners interfere with formation of the toxin-relevant Trm9.Trm112 complex. In contrast to trm11Delta or lys9Delta cells, trm112Delta and mtq2Delta null mutants are zymocin resistant. In line with the identified role that methylation of Sup45 by Mtq2 has for translation termination by the release factor dimer Sup45.Sup35, we observe that SUP45 overexpression and sup45 mutants suppress zymocin. Intriguingly, this suppression correlates with upregulated levels of tRNA species targeted by zymocin's tRNase activity.
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Affiliation(s)
- Patrick Studte
- Institut für Biologie, Bereich Genetik, Martin-Luther-Universität, Halle-Wittenberg, Weinbergweg 10, D-06120 Halle (Saale), Germany
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37
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3D local structure around Zn in Kti11p as a representative Zn-(Cys)4 motif as obtained by MXAN. Biochem Biophys Res Commun 2008; 374:28-32. [PMID: 18606152 DOI: 10.1016/j.bbrc.2008.06.116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2008] [Accepted: 06/19/2008] [Indexed: 11/23/2022]
Abstract
Zinc is an important component of many proteins that play key roles in transcription, translation, and catalysis. Kti11p, DESR1, both belonging to a protein family characterized by a CSL zinc finger domain, and the co-catalytic zinc-protein PML containing a Zn(2+) binding domain called RING or C(3)HC(4) finger are all structurally determined by NMR although the zinc sites are silent to this spectroscopical method. The comparison of X-ray absorption near-edge spectroscopy (XANES) data for the three proteins demonstrates that fingerprints effect is a reliable method for a primary characterization of ligand species. Ab initio full MS calculations performed by MXAN are applied to obtain chemical and stereo structural information around the Zn ion in Kti11p. For the first time this high-spatial resolution technique confirms the formation of a stable Zn tetrahedral configuration with four sulfur ligands, and returns extremely accurate bond angle information between ligands.
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38
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Bär C, Zabel R, Liu S, Stark MJR, Schaffrath R. A versatile partner of eukaryotic protein complexes that is involved in multiple biological processes: Kti11/Dph3. Mol Microbiol 2008; 69:1221-33. [PMID: 18627462 DOI: 10.1111/j.1365-2958.2008.06350.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The Kluyveromyces lactis killer toxin zymocin insensitive 11 (KTI11) gene from Saccharomyces cerevisiae is allelic with the diphthamide synthesis 3 (DPH3) locus. Here, we present evidence that the KTI11 gene product is a versatile partner of proteins and operates in multiple biological processes. Notably, Kti11 immune precipitates contain Elp2 and Elp5, two subunits of the Elongator complex which is involved in transcription, tRNA modification and zymocin toxicity. KTI11 deletion phenocopies Elongator-minus cells and causes antisuppression of nonsense and missense suppressor tRNAs (SUP4, SOE1), zymocin resistance and protection against the tRNase attack of zymocin. In addition and unlike Elongator mutants, kti11 mutants resist diphtheria toxin (DT), protect against ADP-ribosylation of eukaryotic translation elongation factor 2 (eEF2) by DT and induce resistance against sordarin, an eEF2 poisoning antifungal. The latter phenotype applies to all diphthamide mutants (dph1-dph5) tested and Kti11/Dph3 physically interacts with diphthamide synthesis factors Dph1 and Dph2, presumably as part of a trimeric complex. Moreover, we present a separation of function mutation in KTI11, kti11-1, which dissociates zymocin resistance from DT sensitivity. It encodes a C-terminal Kti11 truncation that almost entirely abolishes Elongator interaction without affecting association with Kti13, another Kti11 partner protein.
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Affiliation(s)
- Christian Bär
- Biologicum, Institut für Genetik, Martin-Luther-Universität Halle-Wittenberg, Weinbergweg 10, D-06120 Halle (Saale), Germany
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39
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Klassen R, Paluszynski JP, Wemhoff S, Pfeiffer A, Fricke J, Meinhardt F. The primary target of the killer toxin from Pichia acaciae is tRNA(Gln). Mol Microbiol 2008; 69:681-97. [PMID: 18532979 DOI: 10.1111/j.1365-2958.2008.06319.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Pichia acaciae killer toxin (PaT) arrests yeast cells in the S-phase of the cell cycle and induces DNA double-strand breaks (DSBs). Surprisingly, loss of the tRNA-methyltransferase Trm9 - along with the Elongator complex involved in synthesis of 5-methoxy-carbonyl-methyl (mcm(5)) modification in certain tRNAs - conferred resistance against PaT. Overexpression of mcm(5)-modified tRNAs identified tRNA(Gln)((UUG)) as the intracellular target. Consistently, toxin-challenged cells displayed reduced levels of tRNA(Gln) and in vitro the heterologously expressed active toxin subunit disrupts the integrity of tRNA(Gln)((UUG)). Other than Kluyveromyces lactis zymocin, an endonuclease specific for tRNA(Glu)((UUC)), affecting its target in a mcm(5)-dependent manner, PaT exerts activity also on tRNA(Gln) lacking such modification. As sensitivity is restored in trm9 elp3 double mutants, target tRNA cleavage is selectively inhibited by incomplete wobble uridine modification, as seen in trm9, but not in elp3 or trm9 elp3 cells. In addition to tRNA(Gln)((UUG)), tRNA(Gln)((CUG)) is also cleaved in vitro and overexpression of the corresponding gene increased resistance. Consistent with tRNA(Gln)((CUG)) as an additional TRM9-independent target, overexpression of PaT's tRNase subunit abolishes trm9 resistance. Most interestingly, a functional DSB repair pathway confers PaT but also zymocin resistance, suggesting DNA damage to occur generally concomitant with specific tRNA offence.
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Affiliation(s)
- Roland Klassen
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Corrensstr. 3, D-48149 Münster, Germany
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Zabel R, Bär C, Mehlgarten C, Schaffrath R. Yeast alpha-tubulin suppressor Ats1/Kti13 relates to the Elongator complex and interacts with Elongator partner protein Kti11. Mol Microbiol 2008; 69:175-87. [PMID: 18466297 DOI: 10.1111/j.1365-2958.2008.06273.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The alpha-tubulin suppressor 1 (ATS1) gene and the killer toxin-insensitive 13 (KTI13) locus from Saccharomyces cerevisiae are allelic. The Ats1/Kti13 gene product interacts with the cell polarity factor Nap1 and promotes growth inhibition of S. cerevisiae by zymocin, a tRNAse toxin complex from Kluyveromyces lactis. Kti13 removal causes zymocin resistance, a trait that is typical of defects in the Elongator complex. Here, we show that Kti13 co-purifies with the Elongator partner protein Kti11 and that the Kti11 interaction, not the Nap1 partnership, requires the C-terminus of Kti13. Moreover, Kti13 functionally relates to roles of the Elongator complex in tRNA wobble uridine modification, tRNA suppression of nonsense (SUP4) and missense (SOE1) mutations and tRNA restriction by zymocin. Also, inactivation of Kti13 or Elongator rescues the thermosensitive growth defect of secretory mutants (sec2-59(ts), sec12-4(ts)), suggesting that Kti13 and Elongator affect secretion processes that depend on the GTP exchange factors Sec2 and Sec12 respectively. Distinct from tandem deletions in KTI13 and Elongator genes, a kti13Delta kti11Delta double deletion induces synthetic sickness or lethality. In sum, our data suggest that Kti13 and Kti11 support Elongator functions and that they both share Elongator-independent role(s) that are important for cell viability.
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Affiliation(s)
- René Zabel
- Biologicum, Institut für Biologie, Institutsbereich Genetik, Martin-Luther-Universität, Halle-Wittenberg, Weinbergweg 10, D-06120 Halle (Saale), Germany
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Wu F, Zhang J, Sun J, Huang H, Ji P, Chu W, Yu M, Yang F, Wu Z, Wu J, Shi Y. Solution structure of human DESR1, a CSL zinc-binding protein. Proteins 2008; 71:514-8. [PMID: 18214955 DOI: 10.1002/prot.21915] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Fangming Wu
- National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
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Abstract
Growth inhibition of Saccharomyces cerevisiae by the plasmid-encoded trimeric (alphabetagamma) zymocin toxin from dairy yeast, Kluyveromyces lactis, depends on a multistep response pathway in budding yeast. Following early processes that mediate cell-surface contact by the chitinase alpha-subunit of zymocin, later steps enable import of the gamma-toxin tRNase subunit and cleavage of target tRNAs that carry modified U34 (wobble uridine) bases. With the emergence of zymocin-like toxins, continued zymocin research is expected to yield new insights into the evolution of yeast pathosystems and their lethal modes of action.
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Mehlgarten C, Zink S, Rutter J, Schaffrath R. Dosage suppression of the Kluyveromyces lactis zymocin by Saccharomyces cerevisiae ISR1 and UGP1. FEMS Yeast Res 2007; 7:722-30. [PMID: 17367514 DOI: 10.1111/j.1567-1364.2007.00216.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The Kluyveromyces lactis zymocin complex kills Saccharomyces cerevisiae cells in a process that involves tRNA cleavage by its tRNAse gamma-toxin subunit. In contrast to the gamma-toxin mode of action, the early steps of the zymocin response are less well characterized. Here, we present high-dosage suppressors of zymocin that encode a putative Pkc1-related kinase (ISR1) and UDP-glucose pyrophosphorylase (UGPase) (UGP1). Anti-UGPase Western blots and GAL10 - ISR1 overexpression suggest that zymocin suppression correlates with overproduction of UGPase or Isr1. As judged from protection against exo-zymocin and unaltered sensitivity to endogenous gamma-toxin, high-copy ISR1 and UGP1 operate in early, nontarget steps of the zymocin pathway. Consistent with a recent report on in vitro phosphorylation of Isr1 and UGPase by the CDK Pho85, high-copy ISR1 and UGP1 suppression of zymocin is abolished in a pho85 null mutant lacking CDK activity of Pho85. Moreover, suppression requires UGPase enzyme activity, and ISR1 overexpression also protects against CFW, a chitin-interfering poison. Our data agree with roles for UGPase in cell wall biosynthetic processes and for Isr1 in Pkc1-related cell wall integrity. In sum, high-copy ISR1 and UGP1 cells affect early steps of the zymocin response and potentially prevent the lethal K. lactis killer complex from establishing cell surface recognition and/or contact.
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Affiliation(s)
- Constance Mehlgarten
- Biologicum, Institut für Biologie, Institutsbereich Genetik, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
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Jeske S, Meinhardt F, Klassen R. Extranuclear Inheritance: Virus-Like DNA-Elements in Yeast. ACTA ACUST UNITED AC 2007. [DOI: 10.1007/978-3-540-36832-8_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
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Jablonowski D, Zink S, Mehlgarten C, Daum G, Schaffrath R. tRNAGlu wobble uridine methylation by Trm9 identifies Elongator's key role for zymocin-induced cell death in yeast. Mol Microbiol 2006; 59:677-88. [PMID: 16390459 DOI: 10.1111/j.1365-2958.2005.04972.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Zymocin-induced cell death in Saccharomyces cerevisiae requires the toxin-target (TOT) effector Elongator, a protein complex with functions in transcription, exocytosis and tRNA modification. In line with the latter, trm9Delta cells lacking a tRNA methylase specific for wobble uridine (U(34)) residues survive zymocin and in excess, the Trm9 substrate tRNA(Glu) copies zymocin protection of Elongator mutants. Phenotypes typical of a tot3/elp3Delta Elongator mutant are absent from trm9Delta cells but copied in a tot3Deltatrm9Delta double mutant suggesting that Elongator acts upstream of Trm9. Consistent with Elongator-dependent tRNA modification being more important to mRNA decoding than Trm9, SUP4 and SOE1TRNA suppressors are highly sensitive to loss of Elongator and tRNA U(34) hypomodification. As Trm9 overexpression counteracts the effect of high-copy tRNA(Glu), zymocin suppression by high-copy tRNA(Glu) may reflect tRNA hypomethylation of trm9Delta cells. Thus, Trm9 methylation may enable recognition of tRNA by zymocin, a notion supported by a dramatic reduction of tRNA(Glu) levels in zymocin-treated cells and by cytotoxic zymocin residues conserved between bacterial nucleases and a tRNA modifying GTPase. In sum, Trm9 is a bona fideTOT pathway component whose methylation may be hijacked by zymocin to target tRNA function and eventually, mRNA translation.
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Affiliation(s)
- Daniel Jablonowski
- Biologicum, Institut für Genetik, Martin-Luther-Universität Halle-Wittenberg, Weinbergweg 10, D-06120 Halle, Saale, Germany
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Klassen R, Jablonowski D, Stark MJR, Schaffrath R, Meinhardt F. Mating-type locus control of killer toxins fromKluyveromyces lactisandPichia acaciae. FEMS Yeast Res 2006; 6:404-13. [PMID: 16630280 DOI: 10.1111/j.1567-1364.2005.00006.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Killer-toxin complexes produced by Kluyveromyces lactis and Pichia acaciae inhibit cell proliferation of Saccharomyces cerevisiae. Analysis of their actions in haploid MATalpha cells revealed that introduction of the opposite mating-type locus (MATa) significantly suppressed antizymosis. Together with resistance expressed by MATa/MATalpha diploids, the reciprocal action of MATa or MATalpha in haploids of opposite mating types suggests that these killer toxins may be subject to MAT locus control. Congruently, derepressing the silent mating-type loci, HMR and HML, by removing individual components of the histone deacetylase complex Sir1-4, either by transposon-tagging or by chemically inactivating the histone deacetylase catalytic subunit Sir2, yields toxin resistance. Consistent with MAT control of toxin action, killer-toxin-insensitive S. cerevisiae mutants (kti) become mating-compromised despite resisting the toxins' cell-cycle effects. Mating inhibition largely depends on the time point of toxin application to the mating mixtures and is less pronounced in Elongator mutants, whose resistance to the toxins' cell-cycle effects is the result of toxin-target process deficiencies. In striking contrast, non-Elongator mutants defective in early-response events such as toxin import/activation hardly recover from toxin-induced mating inhibition. This study reveals a novel effect of yeast killer toxins on mating and sexual reproduction that is independent of their impact on cellular proliferation and cell-cycle progression.
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Affiliation(s)
- Roland Klassen
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Münster, Germany
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Lu J, Huang B, Esberg A, Johansson MJO, Byström AS. The Kluyveromyces lactis gamma-toxin targets tRNA anticodons. RNA (NEW YORK, N.Y.) 2005; 11:1648-54. [PMID: 16244131 PMCID: PMC1370851 DOI: 10.1261/rna.2172105] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Kluyveromyces lactis killer strains secrete a heterotrimeric toxin (zymocin), which causes an irreversible growth arrest of sensitive yeast cells. Despite many efforts, the target(s) of the cytotoxic gamma-subunit of zymocin has remained elusive. Here we show that three tRNA species tRNA(Glu)(mcm(5)s(2)UUC), tRNA(Lys)(mcm(5)s(2)UUU), and tRNA(Gln)(mcm(5)s(2)UUG) are the targets of gamma-toxin. The toxin inhibits growth by cleaving these tRNAs at the 3' side of the modified wobble nucleoside 5-methoxycarbonylmethyl-2-thiouridine (mcm(5)s(2)U). Transfer RNA lacking a part of or the entire mcm(5) group is inefficiently cleaved by gamma-toxin, explaining the gamma-toxin resistance of the modification-deficient trm9, elp1-elp6, and kti11-kti13 mutants. The K. lactis gamma-toxin is the first eukaryotic toxin shown to target tRNA.
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Affiliation(s)
- Jian Lu
- Department of Molecular Biology, Umeå University, Sweden
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Huang B, Johansson MJO, Byström AS. An early step in wobble uridine tRNA modification requires the Elongator complex. RNA (NEW YORK, N.Y.) 2005; 11:424-36. [PMID: 15769872 PMCID: PMC1370732 DOI: 10.1261/rna.7247705] [Citation(s) in RCA: 351] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Accepted: 01/06/2005] [Indexed: 05/17/2023]
Abstract
Elongator has been reported to be a histone acetyltransferase complex involved in elongation of RNA polymerase II transcription. In Saccharomyces cerevisiae, mutations in any of the six Elongator protein subunit (ELP1-ELP6) genes or the three killer toxin insensitivity (KTI11-KTI13) genes cause similar pleiotropic phenotypes. By analyzing modified nucleosides in individual tRNA species, we show that the ELP1-ELP6 and KTI11-KTI13 genes are all required for an early step in synthesis of 5-methoxycarbonylmethyl (mcm5) and 5-carbamoylmethyl (ncm5) groups present on uridines at the wobble position in tRNA. Transfer RNA immunoprecipitation experiments showed that the Elp1 and Elp3 proteins specifically coprecipitate a tRNA susceptible to formation of an mcm5 side chain, indicating a direct role of Elongator in tRNA modification. The presence of mcm5U, ncm5U, or derivatives thereof at the wobble position is required for accurate and efficient translation, suggesting that the phenotypes of elp1-elp6 and kti11-kti13 mutants could be caused by a translational defect. Accordingly, a deletion of any ELP1-ELP6 or KTI11-KTI13 gene prevents an ochre suppressor tRNA that normally contains mcm5U from reading ochre stop codons.
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Affiliation(s)
- Bo Huang
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden
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Schaerer-Brodbeck C, Barberis A. Coupling homologous recombination with growth selection in yeast: a tool for construction of random DNA sequence libraries. Biotechniques 2005; 37:202, 204, 206. [PMID: 15335209 DOI: 10.2144/04372bm05] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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50
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Kluyveromyces lactis zymocin and other plasmid-encoded yeast killer toxins. ACTA ACUST UNITED AC 2004. [DOI: 10.1007/b100196] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
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