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Erber L, Hoffmann A, Fallmann J, Hagedorn M, Hammann C, Stadler PF, Betat H, Prohaska S, Mörl M. Unusual Occurrence of Two Bona-Fide CCA-Adding Enzymes in Dictyostelium discoideum. Int J Mol Sci 2020; 21:ijms21155210. [PMID: 32717856 PMCID: PMC7432833 DOI: 10.3390/ijms21155210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/20/2020] [Accepted: 07/22/2020] [Indexed: 01/12/2023] Open
Abstract
Dictyostelium discoideum, the model organism for the evolutionary supergroup of Amoebozoa, is a social amoeba that, upon starvation, undergoes transition from a unicellular to a multicellular organism. In its genome, we identified two genes encoding for tRNA nucleotidyltransferases. Such pairs of tRNA nucleotidyltransferases usually represent collaborating partial activities catalyzing CC- and A-addition to the tRNA 3'-end, respectively. In D. discoideum, however, both enzymes exhibit identical activities, representing bona-fide CCA-adding enzymes. Detailed characterization of the corresponding activities revealed that both enzymes seem to be essential and are regulated inversely during different developmental stages of D. discoideum. Intriguingly, this is the first description of two functionally equivalent CCA-adding enzymes using the same set of tRNAs and showing a similar distribution within the cell. This situation seems to be a common feature in Dictyostelia, as other members of this phylum carry similar pairs of tRNA nucleotidyltransferase genes in their genome.
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Affiliation(s)
- Lieselotte Erber
- Institute for Biochemistry, University of Leipzig, Brüderstraße 34, 04103 Leipzig, Germany; (L.E.); (H.B.)
| | - Anne Hoffmann
- Interdisciplinary Center for Bioinformatics, Leipzig University, Härtelstraße 16-18, 04107 Leipzig, Germany; (A.H.); (J.F.); (P.F.S.); (S.P.)
| | - Jörg Fallmann
- Interdisciplinary Center for Bioinformatics, Leipzig University, Härtelstraße 16-18, 04107 Leipzig, Germany; (A.H.); (J.F.); (P.F.S.); (S.P.)
| | - Monica Hagedorn
- Ribogenetics Biochemistry Lab, Department of Life Sciences and Chemistry, Jacobs University Bremen gGmbH, Campus Ring 1, 28759 Bremen, Germany; (M.H.); (C.H.)
| | - Christian Hammann
- Ribogenetics Biochemistry Lab, Department of Life Sciences and Chemistry, Jacobs University Bremen gGmbH, Campus Ring 1, 28759 Bremen, Germany; (M.H.); (C.H.)
| | - Peter F. Stadler
- Interdisciplinary Center for Bioinformatics, Leipzig University, Härtelstraße 16-18, 04107 Leipzig, Germany; (A.H.); (J.F.); (P.F.S.); (S.P.)
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Competence Center for Scalable Data Services and Solutions, and Leipzig Research Center for Civilization Diseases, Leipzig University, 04103 Leipzig, Germany
- Max Planck Institute for Mathematics in the Sciences, 04103 Leipzig, Germany
- Facultad de Ciencias, Universidad National de Colombia, Sede Bogotá, Carrera 45 No. 26-85, Colombia
- Santa Fe Institute for Complex Systems, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
- Department of Theoretical Chemistry of the University of Vienna, A-1090 Vienna, Austria
| | - Heike Betat
- Institute for Biochemistry, University of Leipzig, Brüderstraße 34, 04103 Leipzig, Germany; (L.E.); (H.B.)
| | - Sonja Prohaska
- Interdisciplinary Center for Bioinformatics, Leipzig University, Härtelstraße 16-18, 04107 Leipzig, Germany; (A.H.); (J.F.); (P.F.S.); (S.P.)
- Computational EvoDevo Group, Department of Computer Science, Leipzig University, Härtelstraße 16-18, 04107 Leipzig, Germany
| | - Mario Mörl
- Institute for Biochemistry, University of Leipzig, Brüderstraße 34, 04103 Leipzig, Germany; (L.E.); (H.B.)
- Correspondence: ; Tel.: +49-341-9736-911; Fax: +49-341-9736-919
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2
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Shikha S, Schneider A. The single CCA-adding enzyme of T. brucei has distinct functions in the cytosol and in mitochondria. J Biol Chem 2020; 295:6138-6150. [PMID: 32234763 DOI: 10.1074/jbc.ra119.011877] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 03/23/2020] [Indexed: 12/27/2022] Open
Abstract
tRNAs universally carry a CCA nucleotide triplet at their 3'-ends. In eukaryotes, the CCA is added post-transcriptionally by the CCA-adding enzyme (CAE). The mitochondrion of the parasitic protozoan Trypanosoma brucei lacks tRNA genes and therefore imports all of its tRNAs from the cytosol. This has generated interest in the tRNA modifications and their distribution in this organism, including how CCA is added to tRNAs. Here, using a BLAST search for genes encoding putative CAE proteins in T. brucei, we identified a single ORF, Tb927.9.8780, as a potential candidate. Knockdown of this putative protein, termed TbCAE, resulted in the accumulation of truncated tRNAs, abolished translation, and inhibited both total and mitochondrial CCA-adding activities, indicating that TbCAE is located both in the cytosol and mitochondrion. However, mitochondrially localized tRNAs were much less affected by the TbCAE ablation than the other tRNAs. Complementation assays revealed that the N-terminal 10 amino acids of TbCAE are dispensable for its activity and mitochondrial localization and that deletion of 10 further amino acids abolishes both. A growth arrest caused by the TbCAE knockdown was rescued by the expression of the cytosolic isoform of yeast CAE, even though it was not imported into mitochondria. This finding indicated that the yeast enzyme complements the essential function of TbCAE by adding CCA to the primary tRNA transcripts. Of note, ablation of the mitochondrial TbCAE activity, which likely has a repair function, only marginally affected growth.
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Affiliation(s)
- Shikha Shikha
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland
| | - André Schneider
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland.
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3
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Erber L, Franz P, Betat H, Prohaska S, Mörl M. Divergent Evolution of Eukaryotic CC- and A-Adding Enzymes. Int J Mol Sci 2020; 21:ijms21020462. [PMID: 31936900 PMCID: PMC7014341 DOI: 10.3390/ijms21020462] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/06/2020] [Accepted: 01/09/2020] [Indexed: 12/04/2022] Open
Abstract
Synthesis of the CCA end of essential tRNAs is performed either by CCA-adding enzymes or as a collaboration between enzymes restricted to CC- and A-incorporation. While the occurrence of such tRNA nucleotidyltransferases with partial activities seemed to be restricted to Bacteria, the first example of such split CCA-adding activities was reported in Schizosaccharomyces pombe. Here, we demonstrate that the choanoflagellate Salpingoeca rosetta also carries CC- and A-adding enzymes. However, these enzymes have distinct evolutionary origins. Furthermore, the restricted activity of the eukaryotic CC-adding enzymes has evolved in a different way compared to their bacterial counterparts. Yet, the molecular basis is very similar, as highly conserved positions within a catalytically important flexible loop region are missing in the CC-adding enzymes. For both the CC-adding enzymes from S. rosetta as well as S. pombe, introduction of the loop elements from closely related enzymes with full activity was able to restore CCA-addition, corroborating the significance of this loop in the evolution of bacterial as well as eukaryotic tRNA nucleotidyltransferases. Our data demonstrate that partial CC- and A-adding activities in Bacteria and Eukaryotes are based on the same mechanistic principles but, surprisingly, originate from different evolutionary events.
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Affiliation(s)
- Lieselotte Erber
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany; (L.E.); (P.F.); (H.B.)
| | - Paul Franz
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany; (L.E.); (P.F.); (H.B.)
| | - Heike Betat
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany; (L.E.); (P.F.); (H.B.)
| | - Sonja Prohaska
- Computational EvoDevo Group, Department of Computer Science, Leipzig University, Härtelstraße 16-18, 04107 Leipzig, Germany;
- Interdisciplinary Center for Bioinformatics, Leipzig University, Härtelstraße 16-18, 04107 Leipzig, Germany
- Santa Fe Institute for Complex Systems, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
| | - Mario Mörl
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany; (L.E.); (P.F.); (H.B.)
- Correspondence: ; Tel.: +49-341-9736-911; Fax: +49-341-9736-919
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Leibovitch M, Reid NE, Victoria J, Hanic-Joyce PJ, Joyce PBM. Analysis of the pathogenic I326T variant of human tRNA nucleotidyltransferase reveals reduced catalytic activity and thermal stability in vitro linked to a conformational change. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1867:616-626. [PMID: 30959222 DOI: 10.1016/j.bbapap.2019.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 03/22/2019] [Accepted: 04/02/2019] [Indexed: 12/22/2022]
Abstract
The I326T mutation in the TRNT1 gene encoding human tRNA nucleotidyltransferase (tRNA-NT) is linked to a relatively mild form of SIFD. Previous work indicated that the I326T variant was unable to incorporate AMP into tRNAs in vitro, however, expression of the mutant allele from a strong heterologous promoter supported in vivo CCA addition to both cytosolic and mitochondrial tRNAs in a yeast strain lacking tRNA-NT. To address this discrepancy, we determined the biochemical and biophysical characteristics of the I326T variant enzyme and the related variant, I326A. Our in vitro analysis revealed that the I326T substitution decreases the thermal stability of the enzyme and causes a ten-fold reduction in enzyme activity. We propose that the structural changes in the I326T variant that lead to these altered parameters result from a rearrangement of helices within the body domain of the protein which can be probed by the inability of the monomeric enzyme to form a covalent dimer in vitro mediated by C373. In addition, we confirm that the effects of the I326T or I326A substitutions are relatively mild in vivo by demonstrating that the mutant alleles support both mitochondrial and cytosolic CCA-addition in yeast.
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Affiliation(s)
- M Leibovitch
- Department of Chemistry and Biochemistry and Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke St. W., Montréal H4B 1R6, Québec, Canada
| | - N E Reid
- Department of Chemistry and Biochemistry and Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke St. W., Montréal H4B 1R6, Québec, Canada
| | - J Victoria
- Department of Chemistry and Biochemistry and Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke St. W., Montréal H4B 1R6, Québec, Canada
| | - P J Hanic-Joyce
- Department of Chemistry and Biochemistry and Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke St. W., Montréal H4B 1R6, Québec, Canada
| | - P B M Joyce
- Department of Chemistry and Biochemistry and Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke St. W., Montréal H4B 1R6, Québec, Canada.
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Reid NE, Ngou JS, Joyce PBM. Schizosaccharomyces pombe contains separate CC- and A-adding tRNA nucleotidyltransferases. Biochem Biophys Res Commun 2018; 508:785-790. [PMID: 30528393 DOI: 10.1016/j.bbrc.2018.11.131] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 11/13/2018] [Accepted: 11/20/2018] [Indexed: 01/22/2023]
Abstract
A specific cytidine-cytidine-adenosine (CCA) sequence is required at the 3'-terminus of all functional tRNAs. This sequence is added during tRNA maturation or repair by tRNA nucleotidyltransferase enzymes. While most eukaryotes have a single enzyme responsible for CCA addition, some bacteria have separate CC- and A-adding activities. The fungus, Schizosaccharomyces pombe, has two genes (cca1 and cca2) that are thought, based on predicted amino acid sequences, to encode tRNA nucleotidyltransferases. Here, we show that both genes together are required to complement a Saccharomyces cerevisiae strain bearing a null mutation in the single gene encoding its tRNA nucleotidyltransferase. Using enzyme assays we show further that the purified S. pombe cca1 gene product specifically adds two cytidine residues to a tRNA substrate lacking this sequence while the cca2 gene product specifically adds the terminal adenosine residue thereby completing the CCA sequence. These data indicate that S. pombe represents the first eukaryote known to have separate CC- and A-adding activities for tRNA maturation and repair. In addition, we propose that a novel structural change in a tRNA nucleotidyltransferase is responsible for defining a CC-adding enzyme.
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Affiliation(s)
- Nathalie E Reid
- Department of Chemistry and Biochemistry, Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke St. W, Montréal, Québec, H4B 1R6, Canada
| | - Judith S Ngou
- Department of Chemistry and Biochemistry, Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke St. W, Montréal, Québec, H4B 1R6, Canada
| | - Paul B M Joyce
- Department of Chemistry and Biochemistry, Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke St. W, Montréal, Québec, H4B 1R6, Canada.
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6
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Leibovitch M, Hanic-Joyce PJ, Joyce PBM. In vitro studies of disease-linked variants of human tRNA nucleotidyltransferase reveal decreased thermal stability and altered catalytic activity. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:527-540. [PMID: 29454993 DOI: 10.1016/j.bbapap.2018.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 02/09/2018] [Accepted: 02/14/2018] [Indexed: 11/15/2022]
Abstract
Mutations in the human TRNT1 gene encoding tRNA nucleotidyltransferase (tRNA-NT), an essential enzyme responsible for addition of the CCA (cytidine-cytidine-adenosine) sequence to the 3'-termini of tRNAs, have been linked to disease phenotypes including congenital sideroblastic anemia with B-cell immunodeficiency, periodic fevers and developmental delay (SIFD) or retinitis pigmentosa with erythrocyte microcytosis. The effects of these disease-linked mutations on the structure and function of tRNA-NT have not been explored. Here we use biochemical and biophysical approaches to study how five SIFD-linked amino acid substitutions (T154I, M158V, L166S, R190I and I223T), residing in the N-terminal head and neck domains of the enzyme, affect the structure and activity of human tRNA-NT in vitro. Our data suggest that the SIFD phenotype is linked to poor stability of the T154I and L166S variant proteins, and to a combination of reduced stability and altered catalytic efficiency in the M158 V, R190I and I223T variants.
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Affiliation(s)
- M Leibovitch
- Department of Chemistry and Biochemistry and Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke St. W., Montréal H4B 1R6, Québec, Canada
| | - P J Hanic-Joyce
- Department of Chemistry and Biochemistry and Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke St. W., Montréal H4B 1R6, Québec, Canada
| | - P B M Joyce
- Department of Chemistry and Biochemistry and Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke St. W., Montréal H4B 1R6, Québec, Canada.
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Bionda T, Gross LE, Becker T, Papasotiriou DG, Leisegang MS, Karas M, Schleiff E. Eukaryotic Hsp70 chaperones in the intermembrane space of chloroplasts. PLANTA 2016; 243:733-47. [PMID: 26669598 DOI: 10.1007/s00425-015-2440-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 11/27/2015] [Indexed: 06/05/2023]
Abstract
MAIN CONCLUSION Multiple eukaryotic Hsp70 typically localized in the cytoplasm are also distributed to the intermembrane space of chloroplasts and might thereby represent the missing link in energizing protein translocation. Protein translocation into organelles is a central cellular process that is tightly regulated. It depends on signals within the preprotein and on molecular machines catalyzing the process. Molecular chaperones participate in transport and translocation of preproteins into organelles to control folding and to provide energy for the individual steps. While most of the processes are explored and the components are identified, the transfer of preproteins into and across the intermembrane space of chloroplasts is not yet understood. The existence of an energy source in this compartment is discussed, because the required transit peptide length for successful translocation into chloroplasts is shorter than that found for mitochondria where energy is provided exclusively by matrix chaperones. Furthermore, a cytosolic-type Hsp70 homologue was proposed as component of the chloroplast translocon in the intermembrane space energizing the initial translocation. The molecular identity of such intermembrane space localized Hsp70 remained unknown, which led to a controversy concerning its existence. We identified multiple cytosolic Hsp70s by mass spectrometry on isolated, thermolysin-treated Medicago sativa chloroplasts. The localization of these Hsp70s of M. sativa or Arabidopsis thaliana in the intermembrane space was confirmed by a self-assembly GFP-based in vivo system. The localization of cytosolic Hsp70s in the stroma of chloroplasts or different mitochondrial compartments could not be observed. Similarly, we could not identify any cytosolic Hsp90 in the intermembrane space of chloroplast. With respect to our results we discuss the possible targeting and function of the Hsp70 found in the intermembrane space.
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Affiliation(s)
- Tihana Bionda
- Molecular Cell Biology of Plants, Goethe University, Max von Laue Str. 9, 60438, Frankfurt, Germany
- Institute of Biochemistry II, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Lucia E Gross
- Molecular Cell Biology of Plants, Goethe University, Max von Laue Str. 9, 60438, Frankfurt, Germany
| | - Thomas Becker
- Molecular Cell Biology of Plants, Goethe University, Max von Laue Str. 9, 60438, Frankfurt, Germany
- Biochemistry and Molecular Biology, ZBMZ, and BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Stefan-Meier-Str. 17, 79104, Freiburg, Germany
| | - Dimitrios G Papasotiriou
- Pharmaceutical Chemistry, Goethe University, Max von Laue Str. 9, 60438, Frankfurt, Germany
- Syngenta Ltd., Jealott's Hill International Research Centre, Bracknell, Berkshire, RG42 6EY, UK
| | - Matthias S Leisegang
- Molecular Cell Biology of Plants, Goethe University, Max von Laue Str. 9, 60438, Frankfurt, Germany
- Institute for Cardiovascular Physiology, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Michael Karas
- Pharmaceutical Chemistry, Goethe University, Max von Laue Str. 9, 60438, Frankfurt, Germany
| | - Enrico Schleiff
- Molecular Cell Biology of Plants, Goethe University, Max von Laue Str. 9, 60438, Frankfurt, Germany.
- Molecular Cell Biology of Plants, Cluster of Excellence Frankfurt, Goethe University, Max von Laue Str. 9, 60438, Frankfurt, Germany.
- Buchmann Institut for Molecular Life Sciences, Max von Laue Str. 9, 60438, Frankfurt, Germany.
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Betat H, Mede T, Tretbar S, Steiner L, Stadler PF, Mörl M, Prohaska SJ. The ancestor of modern Holozoa acquired the CCA-adding enzyme from Alphaproteobacteria by horizontal gene transfer. Nucleic Acids Res 2015; 43:6739-46. [PMID: 26117543 PMCID: PMC4538823 DOI: 10.1093/nar/gkv631] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 06/07/2015] [Indexed: 12/03/2022] Open
Abstract
Transfer RNAs (tRNAs) require the absolutely conserved sequence motif CCA at their 3′-ends, representing the site of aminoacylation. In the majority of organisms, this trinucleotide sequence is not encoded in the genome and thus has to be added post-transcriptionally by the CCA-adding enzyme, a specialized nucleotidyltransferase. In eukaryotic genomes this ubiquitous and highly conserved enzyme family is usually represented by a single gene copy. Analysis of published sequence data allows us to pin down the unusual evolution of eukaryotic CCA-adding enzymes. We show that the CCA-adding enzymes of animals originated from a horizontal gene transfer event in the stem lineage of Holozoa, i.e. Metazoa (animals) and their unicellular relatives, the Choanozoa. The tRNA nucleotidyltransferase, acquired from an α-proteobacterium, replaced the ancestral enzyme in Metazoa. However, in Choanoflagellata, the group of Choanozoa that is closest to Metazoa, both the ancestral and the horizontally transferred CCA-adding enzymes have survived. Furthermore, our data refute a mitochondrial origin of the animal tRNA nucleotidyltransferases.
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Affiliation(s)
- Heike Betat
- Institute for Biochemistry, University of Leipzig, Brüderstraße 34, D-04103 Leipzig, Germany
| | - Tobias Mede
- Computational EvoDevo Group, Department of Computer Science, University of Leipzig, Härtelstraße 16-18, D-04107 Leipzig, Germany
| | - Sandy Tretbar
- Institute for Biochemistry, University of Leipzig, Brüderstraße 34, D-04103 Leipzig, Germany
| | - Lydia Steiner
- Computational EvoDevo Group, Department of Computer Science, University of Leipzig, Härtelstraße 16-18, D-04107 Leipzig, Germany
| | - Peter F Stadler
- Bioinformatics Group, Department of Computer Science, University of Leipzig, Härtelstraße 16-18, D-04107 Leipzig, Germany Interdisciplinary Center for Bioinformatics, University of Leipzig, Härtelstraße 16-18, D-04107 Leipzig, Germany Max-Planck-Institute for Mathematics in the Sciences, Inselstraße 22, D-04103 Leipzig, Germany Fraunhofer Institut für Zelltherapie und Immunologie, Perlickstraße 1, D-04103 Leipzig, Germany Department of Theoretical Chemistry, University of Vienna, Währingerstraße 17, A-1090 Wien, Austria Center for non-coding RNA in Technology and Health, University of Copenhagen, Grønnegårdsvej 3, DK-1870 Frederiksberg, Denmark Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
| | - Mario Mörl
- Institute for Biochemistry, University of Leipzig, Brüderstraße 34, D-04103 Leipzig, Germany
| | - Sonja J Prohaska
- Computational EvoDevo Group, Department of Computer Science, University of Leipzig, Härtelstraße 16-18, D-04107 Leipzig, Germany Interdisciplinary Center for Bioinformatics, University of Leipzig, Härtelstraße 16-18, D-04107 Leipzig, Germany
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9
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Tillmann B, Röth S, Bublak D, Sommer M, Stelzer EHK, Scharf KD, Schleiff E. Hsp90 is involved in the regulation of cytosolic precursor protein abundance in tomato. MOLECULAR PLANT 2015; 8:228-41. [PMID: 25619681 DOI: 10.1016/j.molp.2014.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 09/22/2014] [Accepted: 10/03/2014] [Indexed: 05/09/2023]
Abstract
Cytosolic chaperones are involved in the regulation of cellular protein homeostasis in general. Members of the families of heat stress proteins 70 (Hsp70) and 90 (Hsp90) assist the transport of preproteins to organelles such as chloroplasts or mitochondria. In addition, Hsp70 was described to be involved in the degradation of chloroplast preproteins that accumulate in the cytosol. Because a similar function has not been established for Hsp90, we analyzed the influences of Hsp90 and Hsp70 on the protein abundance in the cellular context using an in vivo system based on mesophyll protoplasts. We observed a differential behavior of preproteins with respect to the cytosolic chaperone-dependent regulation. Some preproteins such as pOE33 show a high dependence on Hsp90, whereas the abundance of preproteins such as pSSU is more strongly dependent on Hsp70. The E3 ligase, C-terminus of Hsp70-interacting protein (Chip), appears to have a more general role in the control of cytosolic protein abundance. We discuss why the different reaction modes are comparable with the cytosolic unfolded protein response.
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Affiliation(s)
- Bodo Tillmann
- Department of Molecular Cell Biology of Plants, Goethe-University, Max-von-Laue Street 9, 60438 Frankfurt am Main, Germany
| | - Sascha Röth
- Department of Molecular Cell Biology of Plants, Goethe-University, Max-von-Laue Street 9, 60438 Frankfurt am Main, Germany
| | - Daniela Bublak
- Department of Molecular Cell Biology of Plants, Goethe-University, Max-von-Laue Street 9, 60438 Frankfurt am Main, Germany
| | - Manuel Sommer
- Department of Molecular Cell Biology of Plants, Goethe-University, Max-von-Laue Street 9, 60438 Frankfurt am Main, Germany; Buchman Institute for Molecular Life Sciences, Goethe University, Max-von-Laue Street 15, 60438 Frankfurt am Main, Germany; Institute of Cell Biology, Goethe-Universität, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Ernst H K Stelzer
- Cluster of Excellence 'Macromolecular Complexes', Goethe-University, 60438 Frankfurt am Main, Germany; Center of Membrane Proteomics, Goethe University, Max-von-Laue Street 9, 60438 Frankfurt am Main, Germany; Buchman Institute for Molecular Life Sciences, Goethe University, Max-von-Laue Street 15, 60438 Frankfurt am Main, Germany; Institute of Cell Biology, Goethe-Universität, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Klaus-Dieter Scharf
- Department of Molecular Cell Biology of Plants, Goethe-University, Max-von-Laue Street 9, 60438 Frankfurt am Main, Germany
| | - Enrico Schleiff
- Department of Molecular Cell Biology of Plants, Goethe-University, Max-von-Laue Street 9, 60438 Frankfurt am Main, Germany; Cluster of Excellence 'Macromolecular Complexes', Goethe-University, 60438 Frankfurt am Main, Germany; Center of Membrane Proteomics, Goethe University, Max-von-Laue Street 9, 60438 Frankfurt am Main, Germany; Buchman Institute for Molecular Life Sciences, Goethe University, Max-von-Laue Street 15, 60438 Frankfurt am Main, Germany.
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10
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Goring ME, Leibovitch M, Gea-Mallorqui E, Karls S, Richard F, Hanic-Joyce PJ, Joyce PBM. The ability of an arginine to tryptophan substitution in Saccharomyces cerevisiae tRNA nucleotidyltransferase to alleviate a temperature-sensitive phenotype suggests a role for motif C in active site organization. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:2097-106. [PMID: 23872483 DOI: 10.1016/j.bbapap.2013.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 07/08/2013] [Accepted: 07/10/2013] [Indexed: 11/15/2022]
Abstract
We report that the temperature-sensitive (ts) phenotype in Saccharomyces cerevisiae associated with a variant tRNA nucleotidyltransferase containing an amino acid substitution at position 189 results from a reduced ability to incorporate AMP and CMP into tRNAs. We show that this defect can be compensated for by a second-site suppressor converting residue arginine 64 to tryptophan. The R64W substitution does not alter the structure or thermal stability of the enzyme dramatically but restores catalytic activity in vitro and suppresses the ts phenotype in vivo. R64 is found in motif A known to be involved in catalysis and nucleotide triphosphate binding while E189 lies within motif C previously thought only to connect the head and neck domains of the protein. Although mutagenesis experiments indicate that residues R64 and E189 do not interact directly, our data suggest a critical role for residue E189 in enzyme structure and function. Both R64 and E189 may contribute to the organization of the catalytic domain of the enzyme. These results, along with overexpression and deletion analyses, show that the ts phenotype of cca1-E189F does not arise from thermal instability of the variant tRNA nucleotidyltransferase but instead from the inability of a partially active enzyme to support growth only at higher temperatures.
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Affiliation(s)
- Mark E Goring
- Department of Biology, Concordia University, Montréal, H4B 1R6, Canada
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