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Dimitrova-Paternoga L, Kasvandik S, Beckert B, Granneman S, Tenson T, Wilson DN, Paternoga H. Structural basis of ribosomal 30S subunit degradation by RNase R. Nature 2024; 626:1133-1140. [PMID: 38326618 PMCID: PMC10901742 DOI: 10.1038/s41586-024-07027-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 01/04/2024] [Indexed: 02/09/2024]
Abstract
Protein synthesis is a major energy-consuming process of the cell that requires the controlled production1-3 and turnover4,5 of ribosomes. Although the past few years have seen major advances in our understanding of ribosome biogenesis, structural insight into the degradation of ribosomes has been lacking. Here we present native structures of two distinct small ribosomal 30S subunit degradation intermediates associated with the 3' to 5' exonuclease ribonuclease R (RNase R). The structures reveal that RNase R binds at first to the 30S platform to facilitate the degradation of the functionally important anti-Shine-Dalgarno sequence and the decoding-site helix 44. RNase R then encounters a roadblock when it reaches the neck region of the 30S subunit, and this is overcome by a major structural rearrangement of the 30S head, involving the loss of ribosomal proteins. RNase R parallels this movement and relocates to the decoding site by using its N-terminal helix-turn-helix domain as an anchor. In vitro degradation assays suggest that head rearrangement poses a major kinetic barrier for RNase R, but also indicate that the enzyme alone is sufficient for complete degradation of 30S subunits. Collectively, our results provide a mechanistic basis for the degradation of 30S mediated by RNase R, and reveal that RNase R targets orphaned 30S subunits using a dynamic mechanism involving an anchored switching of binding sites.
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Affiliation(s)
| | - Sergo Kasvandik
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Bertrand Beckert
- Dubochet Center for Imaging (DCI) at EPFL, EPFL SB IPHYS DCI, Lausanne, Switzerland
| | - Sander Granneman
- Centre for Engineering Biology (SynthSys), University of Edinburgh, Edinburgh, UK
| | - Tanel Tenson
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Daniel N Wilson
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany.
| | - Helge Paternoga
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany.
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2
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Kurshakova MM, Yakusheva YA, Georgieva SG. TREX-2-ORC Complex of D. melanogaster Participates in Nuclear Export of Histone mRNA. DOKL BIOCHEM BIOPHYS 2024; 514:11-15. [PMID: 38189888 PMCID: PMC11021305 DOI: 10.1134/s160767292370059x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 10/20/2023] [Accepted: 10/21/2023] [Indexed: 01/09/2024]
Abstract
The TREX-2-ORC protein complex of D. melanogaster is necessary for the export of the bulk of synthesized poly(A)-containing mRNA molecules from the nucleus to the cytoplasm through the nuclear pores. However, the role of this complex in the export of other types of RNA remains unknown. We have shown that TREX-2-ORC participates in the nuclear export of histone mRNAs: it associates with histone mRNPs, binds to histone H3 mRNA at the 3'-terminal part of the coding region, and participates in the export of histone mRNAs from the nucleus to the cytoplasm.
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Affiliation(s)
- M M Kurshakova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia.
| | - Y A Yakusheva
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - S G Georgieva
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
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3
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Kurshakova MM, Georgieva SG, Kopytova DV. The Human TREX-2 Complex Interacts with Subunits of the ORC Complex. DOKL BIOCHEM BIOPHYS 2023; 513:346-349. [PMID: 38066323 PMCID: PMC10810029 DOI: 10.1134/s1607672923700552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 09/08/2023] [Accepted: 09/10/2023] [Indexed: 01/26/2024]
Abstract
The TREX-2 protein complex is the key complex involved in the export of mRNA from the nucleus to the cytoplasm through the nuclear pores. Previously, a joint protein complex of TREX-2 with ORC was isolated in D. melanogaster. It was shown that the interaction of TREX-2 with ORC is necessary for efficient mRNA export from the nucleus to the cytoplasm. In this work, we showed that the TREX-2-ORC joint complex is also formed in human cells.
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Affiliation(s)
- M M Kurshakova
- Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia.
| | - S G Georgieva
- Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - D V Kopytova
- Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
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4
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Yang Y, Guo L, Chen L, Gong B, Jia D, Sun Q. Nuclear transport proteins: structure, function, and disease relevance. Signal Transduct Target Ther 2023; 8:425. [PMID: 37945593 PMCID: PMC10636164 DOI: 10.1038/s41392-023-01649-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Revised: 09/13/2023] [Accepted: 09/14/2023] [Indexed: 11/12/2023] Open
Abstract
Proper subcellular localization is crucial for the functioning of biomacromolecules, including proteins and RNAs. Nuclear transport is a fundamental cellular process that regulates the localization of many macromolecules within the nuclear or cytoplasmic compartments. In humans, approximately 60 proteins are involved in nuclear transport, including nucleoporins that form membrane-embedded nuclear pore complexes, karyopherins that transport cargoes through these complexes, and Ran system proteins that ensure directed and rapid transport. Many of these nuclear transport proteins play additional and essential roles in mitosis, biomolecular condensation, and gene transcription. Dysregulation of nuclear transport is linked to major human diseases such as cancer, neurodegenerative diseases, and viral infections. Selinexor (KPT-330), an inhibitor targeting the nuclear export factor XPO1 (also known as CRM1), was approved in 2019 to treat two types of blood cancers, and dozens of clinical trials of are ongoing. This review summarizes approximately three decades of research data in this field but focuses on the structure and function of individual nuclear transport proteins from recent studies, providing a cutting-edge and holistic view on the role of nuclear transport proteins in health and disease. In-depth knowledge of this rapidly evolving field has the potential to bring new insights into fundamental biology, pathogenic mechanisms, and therapeutic approaches.
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Affiliation(s)
- Yang Yang
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Lu Guo
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Lin Chen
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Bo Gong
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, China
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Pediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China.
| | - Qingxiang Sun
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University, and Collaborative Innovation Centre of Biotherapy, Chengdu, China.
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5
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Joshua IM, Lin M, Mardjuki A, Mazzola A, Höfken T. A Protein-Protein Interaction Analysis Suggests a Wide Range of New Functions for the p21-Activated Kinase (PAK) Ste20. Int J Mol Sci 2023; 24:15916. [PMID: 37958899 PMCID: PMC10647699 DOI: 10.3390/ijms242115916] [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: 09/20/2023] [Revised: 10/25/2023] [Accepted: 10/30/2023] [Indexed: 11/15/2023] Open
Abstract
The p21-activated kinases (PAKs) are important signaling proteins. They contribute to a surprisingly wide range of cellular processes and play critical roles in a number of human diseases including cancer, neurological disorders and cardiac diseases. To get a better understanding of PAK functions, mechanisms and integration of various cellular activities, we screened for proteins that bind to the budding yeast PAK Ste20 as an example, using the split-ubiquitin technique. We identified 56 proteins, most of them not described previously as Ste20 interactors. The proteins fall into a small number of functional categories such as vesicle transport and translation. We analyzed the roles of Ste20 in glucose metabolism and gene expression further. Ste20 has a well-established role in the adaptation to changing environmental conditions through the stimulation of mitogen-activated protein kinase (MAPK) pathways which eventually leads to transcription factor activation. This includes filamentous growth, an adaptation to nutrient depletion. Here we show that Ste20 also induces filamentous growth through interaction with nuclear proteins such as Sac3, Ctk1 and Hmt1, key regulators of gene expression. Combining our observations and the data published by others, we suggest that Ste20 has several new and unexpected functions.
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Affiliation(s)
| | - Meng Lin
- Institute of Biochemistry, Kiel University, 24118 Kiel, Germany
| | - Ariestia Mardjuki
- Division of Biosciences, Brunel University London, Uxbridge UB8 3PH, UK; (I.M.J.)
| | - Alessandra Mazzola
- Division of Biosciences, Brunel University London, Uxbridge UB8 3PH, UK; (I.M.J.)
- Department of Biopathology and Medical and Forensic Biotechnologies, University of Palermo, 90133 Palermo, Italy
| | - Thomas Höfken
- Division of Biosciences, Brunel University London, Uxbridge UB8 3PH, UK; (I.M.J.)
- Institute of Biochemistry, Kiel University, 24118 Kiel, Germany
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Kehlenbach RH, Neumann P, Ficner R, Dickmanns A. Interaction of nucleoporins with nuclear transport receptors: a structural perspective. Biol Chem 2023; 404:791-805. [PMID: 37210735 DOI: 10.1515/hsz-2023-0155] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 05/04/2023] [Indexed: 05/23/2023]
Abstract
Soluble nuclear transport receptors and stationary nucleoporins are at the heart of the nucleocytoplasmic transport machinery. A subset of nucleoporins contains characteristic and repetitive FG (phenylalanine-glycine) motifs, which are the basis for the permeability barrier of the nuclear pore complex (NPC) that controls transport of macromolecules between the nucleus and the cytoplasm. FG-motifs can interact with each other and/or with transport receptors, mediating their translocation across the NPC. The molecular details of homotypic and heterotypic FG-interactions have been analyzed at the structural level. In this review, we focus on the interactions of nucleoporins with nuclear transport receptors. Besides the conventional FG-motifs as interaction spots, a thorough structural analysis led us to identify additional similar motifs at the binding interface between nucleoporins and transport receptors. A detailed analysis of all known human nucleoporins revealed a large number of such phenylalanine-containing motifs that are not buried in the predicted 3D-structure of the respective protein but constitute part of the solvent-accessible surface area. Only nucleoporins that are rich in conventional FG-repeats are also enriched for these motifs. This additional layer of potential low-affinity binding sites on nucleoporins for transport receptors may have a strong impact on the interaction of transport complexes with the nuclear pore and, thus, the efficiency of nucleocytoplasmic transport.
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Affiliation(s)
- Ralph H Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany
| | - Piotr Neumann
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, GZMB, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, D-37077 Göttingen, Germany
| | - Ralf Ficner
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, GZMB, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, D-37077 Göttingen, Germany
| | - Achim Dickmanns
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, GZMB, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, D-37077 Göttingen, Germany
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7
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Vdovina YA, Kurshakova MM, Georgieva SG, Kopytova DV. PCID2 Subunit of the Drosophila TREX-2 Complex Has Two RNA-Binding Regions. Curr Issues Mol Biol 2023; 45:5662-5676. [PMID: 37504273 PMCID: PMC10378293 DOI: 10.3390/cimb45070357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/29/2023] [Accepted: 06/29/2023] [Indexed: 07/29/2023] Open
Abstract
Drosophila PCID2 is a subunit of the TREX-2 mRNA nuclear export complex. Although the complex has long been studied in eukaryotes, it is still unclear how TREX-2 interacts with mRNA in multicellular organisms. Here, the interaction between Drosophila PCID2 and the ras2 RNA was studied by EMSA. We show that the C-terminal region of the WH domain of PCID2 specifically binds the 3'-noncoding region of the ras2 RNA. While the same region of PCID2 interacts with the Xmas-2 subunit of the TREX-2 complex, PCID2 interacts with RNA independently of Xmas-2. An additional RNA-binding region (M region) was identified in the N-terminal part of the PCI domain and found to bind RNA nonspecifically. Point mutations of evolutionarily conserved amino acid residues in this region completely abolish the PCID2-RNA interaction, while a deletion of the C-terminal domain only partly decreases it. Thus, the specific interaction of PCID2 with RNA requires nonspecific PCID2-RNA binding.
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Affiliation(s)
- Yulia A Vdovina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Maria M Kurshakova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Sofia G Georgieva
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Daria V Kopytova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
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8
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Kurshakova MM, Georgieva SG, Kopytova DV. The Xmas-2 Protein of Drosophila melanogaster Undergoes Cleavage into Two Fragments. DOKL BIOCHEM BIOPHYS 2023; 509:37-40. [PMID: 37340289 DOI: 10.1134/s1607672923700163] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/07/2022] [Accepted: 11/10/2022] [Indexed: 06/22/2023]
Abstract
The TREX-2 complex integrates several stages of gene expression, such as transcriptional activation and mRNA export. In D. melanogaster, TREX-2 consists of four major proteins: Xmas-2, ENY2, PCID2, and Sem1p. The Xmas-2 protein is the core subunit of the complex, with which other TREX-2 subunits interact. Xmas-2 homologues were found in all higher eukaryotes. Previously, it was shown that the human Xmas-2 homologue, GANP protein, can undergo cleavage into two parts, probably during apoptosis. We showed that the Xmas-2 protein of D. melanogaster can also split into two fragments. The resulting fragments of the protein correspond to the two large Xmas-2 domains. Protein splitting is observed both in vivo and in vitro. However, Xmas-2 cleavage in D. melanogaster is observed under normal conditions and is probably a part of the mechanism of transcription and mRNA export regulation in D. melanogaster.
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Affiliation(s)
- M M Kurshakova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - S G Georgieva
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - D V Kopytova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia.
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Vaishali, Dimitrova-Paternoga L, Haubrich K, Sun M, Ephrussi A, Hennig J. Validation and classification of RNA binding proteins identified by mRNA interactome capture. RNA (NEW YORK, N.Y.) 2021; 27:1173-1185. [PMID: 34215685 PMCID: PMC8456996 DOI: 10.1261/rna.078700.121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
RNA binding proteins (RBPs) take part in all steps of the RNA life cycle and are often essential for cell viability. Most RBPs have a modular organization and comprise a set of canonical RNA binding domains. However, in recent years a number of high-throughput mRNA interactome studies on yeast, mammalian cell lines, and whole organisms have uncovered a multitude of novel mRNA interacting proteins that lack classical RNA binding domains. Whereas a few have been confirmed to be direct and functionally relevant RNA binders, biochemical and functional validation of RNA binding of most others is lacking. In this study, we used a combination of NMR spectroscopy and biochemical studies to test the RNA binding properties of six putative RBPs. Half of the analyzed proteins showed no interaction, whereas the other half displayed weak chemical shift perturbations upon titration with RNA. One of the candidates we found to interact weakly with RNA in vitro is Drosophila melanogaster end binding protein 1 (EB1), a master regulator of microtubule plus-end dynamics. Further analysis showed that EB1's RNA binding occurs on the same surface as that with which EB1 interacts with microtubules. RNA immunoprecipitation and colocalization experiments suggest that EB1 is a rather nonspecific, opportunistic RNA binder. Our data suggest that care should be taken when embarking on an RNA binding study involving these unconventional, novel RBPs, and we recommend initial and simple in vitro RNA binding experiments.
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Affiliation(s)
- Vaishali
- Developmental Biology Unit, EMBL Heidelberg, 69117 Heidelberg, Germany
- Faculty of Biosciences, Heidelberg University, Heidelberg 69120, Germany
| | - Lyudmila Dimitrova-Paternoga
- Developmental Biology Unit, EMBL Heidelberg, 69117 Heidelberg, Germany
- Structural and Computational Biology Unit, EMBL Heidelberg, 69117 Heidelberg, Germany
| | - Kevin Haubrich
- Structural and Computational Biology Unit, EMBL Heidelberg, 69117 Heidelberg, Germany
| | - Mai Sun
- Genome Biology Unit, EMBL Heidelberg, 69117 Heidelberg, Germany
| | - Anne Ephrussi
- Developmental Biology Unit, EMBL Heidelberg, 69117 Heidelberg, Germany
| | - Janosch Hennig
- Structural and Computational Biology Unit, EMBL Heidelberg, 69117 Heidelberg, Germany
- Biochemistry IV, Biophysical Chemistry, University of Bayreuth, 95447 Bayreuth, Germany
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Evolution and diversification of the nuclear pore complex. Biochem Soc Trans 2021; 49:1601-1619. [PMID: 34282823 PMCID: PMC8421043 DOI: 10.1042/bst20200570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/18/2021] [Accepted: 06/21/2021] [Indexed: 12/21/2022]
Abstract
The nuclear pore complex (NPC) is responsible for transport between the cytoplasm and nucleoplasm and one of the more intricate structures of eukaryotic cells. Typically composed of over 300 polypeptides, the NPC shares evolutionary origins with endo-membrane and intraflagellar transport system complexes. The modern NPC was fully established by the time of the last eukaryotic common ancestor and, hence, prior to eukaryote diversification. Despite the complexity, the NPC structure is surprisingly flexible with considerable variation between lineages. Here, we review diversification of the NPC in major taxa in view of recent advances in genomic and structural characterisation of plant, protist and nucleomorph NPCs and discuss the implications for NPC evolution. Furthermore, we highlight these changes in the context of mRNA export and consider how this process may have influenced NPC diversity. We reveal the NPC as a platform for continual evolution and adaptation.
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11
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SAC3B is a target of CML19, the centrin 2 of Arabidopsis thaliana. Biochem J 2020; 477:173-189. [PMID: 31860002 DOI: 10.1042/bcj20190674] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 01/15/2023]
Abstract
Arabidopsis centrin 2, also known as calmodulin-like protein 19 (CML19), is a member of the EF-hand superfamily of calcium (Ca2+)-binding proteins. In addition to the notion that CML19 interacts with the nucleotide excision repair protein RAD4, CML19 was suggested to be a component of the transcription export complex 2 (TREX-2) by interacting with SAC3B. However, the molecular determinants of this interaction have remained largely unknown. Herein, we identified a CML19-binding site within the C-terminus of SAC3B and characterized the binding properties of the corresponding 26-residue peptide (SAC3Bp), which exhibits the hydrophobic triad centrin-binding motif in a reversed orientation (I8W4W1). Using a combination of spectroscopic and calorimetric experiments, we shed light on the SAC3Bp-CML19 complex structure in solution. We demonstrated that the peptide interacts not only with Ca2+-saturated CML19, but also with apo-CML19 to form a protein-peptide complex with a 1 : 1 stoichiometry. Both interactions involve hydrophobic and electrostatic contributions and include the burial of Trp residues of SAC3Bp. However, the peptide likely assumes different conformations upon binding to apo-CML19 or Ca2+-CML19. Importantly, the peptide dramatically increases the affinity for Ca2+ of CML19, especially of the C-lobe, suggesting that in vivo the protein would be Ca2+-saturated and bound to SAC3B even at resting Ca2+-levels. Our results, providing direct evidence that Arabidopsis SAC3B is a CML19 target and proposing that CML19 can bind to SAC3B through its C-lobe independent of a Ca2+ stimulus, support a functional role for these proteins in TREX-2 complex and mRNA export.
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12
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Xie Y, Ren Y. Mechanisms of nuclear mRNA export: A structural perspective. Traffic 2019; 20:829-840. [PMID: 31513326 DOI: 10.1111/tra.12691] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 08/26/2019] [Indexed: 12/28/2022]
Abstract
Export of mRNA from the nucleus to the cytoplasm is a critical process for all eukaryotic gene expression. As mRNA is synthesized, it is packaged with a myriad of RNA-binding proteins to form ribonucleoprotein particles (mRNPs). For each step in the processes of maturation and export, mRNPs must have the correct complement of proteins. Much of the mRNA export pathway revolves around the heterodimeric export receptor yeast Mex67•Mtr2/human NXF1•NXT1, which is recruited to signal the completion of nuclear mRNP assembly, mediates mRNP targeting/translocation through the nuclear pore complex (NPC), and is displaced at the cytoplasmic side of the NPC to release the mRNP into the cytoplasm. Directionality of the transport is governed by at least two DEAD-box ATPases, yeast Sub2/human UAP56 in the nucleus and yeast Dbp5/human DDX19 at the cytoplasmic side of the NPC, which respectively mediate the association and dissociation of Mex67•Mtr2/NXF1•NXT1 onto the mRNP. Here we review recent progress from structural studies of key constituents in different steps of nuclear mRNA export. These findings have laid the foundation for further studies to obtain a comprehensive mechanistic view of the mRNA export pathway.
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Affiliation(s)
- Yihu Xie
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Yi Ren
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee
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13
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Unique Interactions of the Nuclear Export Receptors TbMex67 and TbMtr2 with Components of the 5S Ribonuclear Particle in Trypanosoma brucei. mSphere 2019; 4:4/4/e00471-19. [PMID: 31413174 PMCID: PMC6695518 DOI: 10.1128/msphere.00471-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Trypanosoma brucei is the causative agent for both African sleeping sickness in humans and nagana in cattle. Ribosome biogenesis in these pathogens requires both conserved and trypanosome-specific proteins to coordinate in a complex pathway. We have previously shown that the trypanosome-specific proteins P34/P37 are essential to the interaction of the TbNmd3-TbXpoI export complex with the 60S ribosomal subunits, allowing their translocation across the nuclear envelope. Our recent studies show that the trypanosome orthologues of the auxiliary export proteins TbMex67-TbMtr2 are required for ribosome assembly, proper rRNA processing, and polysome formation. Here we show that TbMex67-TbMtr2 interact with members of the 60S ribosomal subunit 5S RNP. Although TbMex67 has a unique structure among the Mex67 orthologues and forms unique interactions with the 5S RNP, particularly with trypanosome-specific P34/P37, it performs a conserved function in ribosome assembly. These unique structures and parasite-specific interactions may provide new therapeutic targets against this important parasite. Eukaryotic ribosome biogenesis is a complicated and highly conserved biological process. A critical step in ribosome biogenesis is the translocation of the immature ribosomal subunits from the nucleoplasm, across the nucleopore complex, to the cytoplasm where they undergo final maturation. Many nonribosomal proteins are needed to facilitate export of the ribosomal subunits, and one complex participating in export of the pre-60S in Saccharomyces cerevisiae is the heterodimer Mex67-Mtr2. In Trypanomsoma brucei, the process of ribosome biogenesis differs from the yeast process in key steps and is not yet fully characterized. However, our laboratory has previously identified the trypanosome-specific proteins P34/P37 and has shown that P34/P37 are necessary for the formation of the 5S ribonuclear particle (RNP) and for the nuclear export of the pre-60S subunit. We have also shown that loss of TbMex67 or TbMtr2 leads to aberrant ribosome formation, rRNA processing, and polysome formation in T. brucei. In this study, we characterize the interaction of TbMex67 and TbMtr2 with the components of the 5S RNP (P34/P37, L5 and 5S rRNA) of the 60S subunit. We demonstrate that TbMex67 directly interacts with P34 and L5 proteins as well as 5S rRNA, while TbMtr2 does not. Using protein sequence alignments and structure prediction modeling, we show that TbMex67 lacks the amino acids previously shown to be essential for binding to 5S rRNA in yeast and in general aligns more closely with the human orthologue (NXF1 or TAP). This work suggests that the T. brucei Mex67-Mtr2 binds ribosomal cargo differently from the yeast system. IMPORTANCETrypanosoma brucei is the causative agent for both African sleeping sickness in humans and nagana in cattle. Ribosome biogenesis in these pathogens requires both conserved and trypanosome-specific proteins to coordinate in a complex pathway. We have previously shown that the trypanosome-specific proteins P34/P37 are essential to the interaction of the TbNmd3-TbXpoI export complex with the 60S ribosomal subunits, allowing their translocation across the nuclear envelope. Our recent studies show that the trypanosome orthologues of the auxiliary export proteins TbMex67-TbMtr2 are required for ribosome assembly, proper rRNA processing, and polysome formation. Here we show that TbMex67-TbMtr2 interact with members of the 60S ribosomal subunit 5S RNP. Although TbMex67 has a unique structure among the Mex67 orthologues and forms unique interactions with the 5S RNP, particularly with trypanosome-specific P34/P37, it performs a conserved function in ribosome assembly. These unique structures and parasite-specific interactions may provide new therapeutic targets against this important parasite.
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Abstract
The Three prime repair exonuclease 2 (TREX-2) complex functions as a platform to which many of the components of the nuclear mRNA processing machinery bind, facilitating integration of this phase of the gene expression pathway, as well as mediating the re-positioning of highly regulated actively transcribing genes (such as GAL1) to nuclear pores (NPCs) to accelerate their activation. In Saccharomyces cerevisiae the TREX-2 complex is based on a Sac3 scaffold to which Thp1, Sem1, Cdc31 and two Sus1 chains are bound. A combination of X-ray crystallography and electron microscopy studies have established the structure of two major regions of this complex: the M-region that functions to bind nucleic acids and the CID region that functions to link the complex to nuclear pores. These structures have facilitated the engineering of mutants that have been used to define the contributions made by the TREX-2 complex to locating high-expressed genes to nuclear pores and the contributions made to mRNA nuclear export.
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Affiliation(s)
- Murray Stewart
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK.
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15
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Xiao C, Yu Q, Zhang B, Li J, Zhang D, Li M. The mRNA export factor Sac3 maintains nuclear homeostasis and regulates cytoskeleton organization in Candida albicans. Future Microbiol 2018; 13:283-296. [PMID: 29436239 DOI: 10.2217/fmb-2017-0191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AIM In eukaryotes, the nuclear export of mRNAs is essential for gene expression and regulations of numerous cellular processes. This study aimed to identify the mRNA export factor Sac3 in Candida albicans. MATERIALS & METHODS A sac3Δ/Δ mutant was obtained using PCR-mediated homologous recombination. RESULTS Disruption of SAC3 caused abnormal accumulation of mRNA in the nuclei. Further investigations revealed that sac3Δ/Δ mutant exhibited a severely growth defect, which was related to abnormal aggregation of microtubules. Moreover, loss of Sac3 caused a defect in hyphal polarized growth, which was associated with depolarization of actin cytoskeleton. In addition, the virulence of sac3Δ/Δ mutant was seriously attenuated. CONCLUSION Our findings provide new insights into the mRNA export factor Sac3 in C. albicans.
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Affiliation(s)
- Chenpeng Xiao
- Key Laboratory of Molecular Microbiology & Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Qilin Yu
- Key Laboratory of Molecular Microbiology & Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Bing Zhang
- Key Laboratory of Molecular Microbiology & Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Jianrong Li
- Key Laboratory of Molecular Microbiology & Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Dan Zhang
- Key Laboratory of Molecular Microbiology & Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Mingchun Li
- Key Laboratory of Molecular Microbiology & Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, PR China
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16
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Gordon JMB, Aibara S, Stewart M. Structure of the Sac3 RNA-binding M-region in the Saccharomyces cerevisiae TREX-2 complex. Nucleic Acids Res 2017; 45:5577-5585. [PMID: 28334829 PMCID: PMC5435946 DOI: 10.1093/nar/gkx158] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 03/01/2017] [Indexed: 01/29/2023] Open
Abstract
Transcription-export complex 2 (TREX-2, or THSC) facilitates localization of actively transcribing genes such as GAL1 to the nuclear periphery, contributes to the generation of export-competent mRNPs and influences gene expression through interactions with Mediator. TREX-2 is based on a Sac3 scaffold to which Thp1, Sem1, Cdc31 and Sus1 bind and consists of three modules: the N-region (Sac3∼1-100), which binds mRNA export factor Mex67:Mtr2; the M-region, in which Thp1 and Sem1 bind to Sac3∼100-550; and the CID region in which Cdc31 and two Sus1 chains bind to Sac3∼720-805. Although the M-region of Sac3 was originally thought to encompass residues ∼250-550, we report here the 2.3Å resolution crystal structure of a complex containing Sac3 residues 60–550 that indicates that the TPR-like repeats of the M-region extend to residue 137 and that residues 90–125 form a novel loop that links Sac3 to Thp1. These new structural elements are important for growth and mRNA export in vivo. Although deleting Sac3 residues 1–90 produced a wild-type phenotype, deletion of the loop as well generated growth defects at 37°C, whereas the deletion of residues 1–250 impaired mRNA export and also generated longer lag times when glucose or raffinose was replaced by galactose as the carbon source.
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Affiliation(s)
- James M B Gordon
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Shintaro Aibara
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Murray Stewart
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
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17
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Robinson GC, Vegunta Y, Gabus C, Gaubitz C, Thore S. Cloning, expression, purification, and characterisation of the HEAT-repeat domain of TOR from the thermophilic eukaryote Chaetomium thermophilum. Protein Expr Purif 2017; 133:90-95. [PMID: 28284995 DOI: 10.1016/j.pep.2017.03.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 03/02/2017] [Accepted: 03/06/2017] [Indexed: 11/29/2022]
Abstract
The Target of Rapamycin Complex is a central controller of cell growth and differentiation in eukaryotes. Its global architecture has been described by cryoelectron microscopy, and regions of its central TOR protein have been described by X-ray crystallography. However, the N-terminal region of this protein, which consists of a series of HEAT repeats, remains uncharacterised at high resolution, most likely due to the absence of a suitable purification procedure. Here, we present a robust method for the preparation of the HEAT-repeat domain, utilizing the thermophilic fungus Chaetomium thermophilum as a source organism. We describe construct design and stable expression in insect cells. An efficient two-step purification procedure is presented, and the purified product is characterised by SEC and MALDI-TOF MS. The methods described pave the way for a complete high-resolution characterisation of this elusive region of the TOR protein.
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Affiliation(s)
- Graham C Robinson
- Department of Molecular Biology, University of Geneva, 30 quai Ernest Ansermet, 1211 Geneva, Switzerland
| | - Yogesh Vegunta
- Department of Molecular Biology, University of Geneva, 30 quai Ernest Ansermet, 1211 Geneva, Switzerland
| | - Caroline Gabus
- Department of Molecular Biology, University of Geneva, 30 quai Ernest Ansermet, 1211 Geneva, Switzerland
| | - Christl Gaubitz
- Department of Molecular Biology, University of Geneva, 30 quai Ernest Ansermet, 1211 Geneva, Switzerland
| | - Stéphane Thore
- Department of Molecular Biology, University of Geneva, 30 quai Ernest Ansermet, 1211 Geneva, Switzerland; INSERM U-1212, CNRS UMR-5320, Université de Bordeaux, 146 rue Léo Saignat, 33000 Bordeaux, France.
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18
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Baßler J, Ahmed YL, Kallas M, Kornprobst M, Calviño FR, Gnädig M, Thoms M, Stier G, Ismail S, Kharde S, Castillo N, Griesel S, Bastuck S, Bradatsch B, Thomson E, Flemming D, Sinning I, Hurt E. Interaction network of the ribosome assembly machinery from a eukaryotic thermophile. Protein Sci 2017; 26:327-342. [PMID: 27863450 DOI: 10.1002/pro.3085] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 10/24/2016] [Accepted: 11/08/2016] [Indexed: 12/30/2022]
Abstract
Ribosome biogenesis in eukaryotic cells is a highly dynamic and complex process innately linked to cell proliferation. The assembly of ribosomes is driven by a myriad of biogenesis factors that shape pre-ribosomal particles by processing and folding the ribosomal RNA and incorporating ribosomal proteins. Biochemical approaches allowed the isolation and characterization of pre-ribosomal particles from Saccharomyces cerevisiae, which lead to a spatiotemporal map of biogenesis intermediates along the path from the nucleolus to the cytoplasm. Here, we cloned almost the entire set (∼180) of ribosome biogenesis factors from the thermophilic fungus Chaetomium thermophilum in order to perform an in-depth analysis of their protein-protein interaction network as well as exploring the suitability of these thermostable proteins for structural studies. First, we performed a systematic screen, testing about 80 factors for crystallization and structure determination. Next, we performed a yeast 2-hybrid analysis and tested about 32,000 binary combinations, which identified more than 1000 protein-protein contacts between the thermophilic ribosome assembly factors. To exemplary verify several of these interactions, we performed biochemical reconstitution with the focus on the interaction network between 90S pre-ribosome factors forming the ctUTP-A and ctUTP-B modules, and the Brix-domain containing assembly factors of the pre-60S subunit. Our work provides a rich resource for biochemical reconstitution and structural analyses of the conserved ribosome assembly machinery from a eukaryotic thermophile.
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Affiliation(s)
- Jochen Baßler
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Yasar Luqman Ahmed
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Martina Kallas
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Markus Kornprobst
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Fabiola R Calviño
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Marén Gnädig
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Matthias Thoms
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Gunter Stier
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Sherif Ismail
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Satyavati Kharde
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Nestor Castillo
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Sabine Griesel
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Sonja Bastuck
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Bettina Bradatsch
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Emma Thomson
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Dirk Flemming
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Irmgard Sinning
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
| | - Ed Hurt
- Biochemistry Center Heidelberg BZH, University of Heidelberg, Heidelberg, 69120, Germany
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19
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Popova VV, Glukhova AA, Georgieva SG, Kopytova DV. Interactions of the TREX-2 complex with mRNP particle of β-tubulin 56D gene. Mol Biol 2016. [DOI: 10.1134/s0026893316060157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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20
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The Sac3 TPR-like region in the Saccharomyces cerevisiae TREX-2 complex is more extensive but independent of the CID region. J Struct Biol 2016; 195:316-324. [PMID: 27422657 PMCID: PMC4991852 DOI: 10.1016/j.jsb.2016.07.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 07/08/2016] [Accepted: 07/11/2016] [Indexed: 11/21/2022]
Abstract
Transcription-export complex 2 (TREX-2 complex) facilitates the localization of actively transcribing genes to the nuclear periphery and also functions to contribute to the generation of export-competent mRNPs through interactions with the general mRNA nuclear export factor Mex67:Mtr2. The TREX-2 complex is based on a Sac3 scaffold to which Thp1, Sem1, Cdc31, and Sus1 bind. TREX-2 can be subdivided into two modules: one, in which Thp1 and Sem1 bind to the Sac3M region (residues ∼100–551), and the other in which Cdc31 and two Sus1 chains bind to the Sac3CID region (residues ∼710–805). Complementary structural analyses using X-ray crystallography, electron microscopy, and small-angle X-ray scattering of the Saccharomyces cerevisiae TREX-2 complex, expressed using Baculovirus-infected Sf9 cells, have indicated that the TPR-like repeats of the Sac3M region extend considerably further towards the N-terminus than previously thought, and also indicate that this region and Sac3CID:Sus1:Cdc31 region of the S. cerevisiae complex are structurally independent. Although the density visible accounted for only ∼100 kDa, a 5.3 Å resolution cryo-EM reconstruction was obtained of the M-region of TREX-2 that showed an additional three putative α-helices extending towards the Sac3 N-terminus and these helices were also seen in a 4.9 Å resolution structure obtained by X-ray crystallography. Summary statement We describe the expression, purification and structural characterization of the S. cerevisiae TREX-2 complex and demonstrate that the Sac3 TPR-like repeats are more extensive than previously thought and that the M- and CID-regions do not appear to have a defined spatial orientation.
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Gasse L, Flemming D, Hurt E. Coordinated Ribosomal ITS2 RNA Processing by the Las1 Complex Integrating Endonuclease, Polynucleotide Kinase, and Exonuclease Activities. Mol Cell 2016; 60:808-815. [PMID: 26638174 DOI: 10.1016/j.molcel.2015.10.021] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 09/11/2015] [Accepted: 10/09/2015] [Indexed: 12/28/2022]
Abstract
The rapidly evolving internal transcribed spacer 2 (ITS2) in the pre-ribosomal RNA is one of the most commonly applied phylogenetic markers at species and genus level. Yet, during ribosome biogenesis ITS2 is removed in all eukaryotes by a common, but still unknown, mechanism. Here we describe the existence of an RNA processome, assembled from four conserved subunits, Las1-Grc3-Rat1-Rai1, that carries all the necessary RNA processing enzymes to mediate coordinated ITS2 rRNA removal. Las1 is the long-sought-after endonuclease cleaving 27SB pre-rRNA at site C2 to yield a 5'-OH end at the 26S pre-rRNA and 2',3' cyclic phosphate at the 3' end of 7S pre-rRNA. Subsequently, polynucleotide kinase Grc3 catalyzes ATP-dependent 5'-OH phosphorylation of 26S pre-rRNA, which in turn enables Rat1-Rai1 exonuclease to generate 25S' pre-rRNA. ITS2 processing is reminiscent of tRNA splicing, but instead of subsequent tRNA ligation, the Las1 complex carries along an exonuclease tool to degrade the ITS2 rRNA.
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Affiliation(s)
- Lisa Gasse
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, Heidelberg 69120, Germany
| | - Dirk Flemming
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, Heidelberg 69120, Germany
| | - Ed Hurt
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, Heidelberg 69120, Germany.
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22
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Grecu D, Irudayaraj VPR, Martinez-Sanz J, Mallet JM, Assairi L. A chirality change in XPC- and Sfi1-derived peptides affects their affinity for centrin. Peptides 2016; 78:77-86. [PMID: 26923803 DOI: 10.1016/j.peptides.2016.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/18/2016] [Accepted: 02/19/2016] [Indexed: 12/30/2022]
Abstract
The Ca(2+)-binding protein centrin binds to a hydrophobic motif (W(1)xxL(4)xxxL(8)) included in the sequence of several cellular targets: XPC (xeroderma pigmentosum group C protein), Sfi1 (suppressor of fermentation-induced loss of stress resistance protein1), and Sac3 [the central component of the transcription and mRNA export (TREX-2) complex]. However, centrin binding occurs in a reversed orientation (L(8)xxxL(4)xxW(1)) for Sfi1 and Sac3 compared with XPC. Because D-peptides have been investigated for future therapeutic use, we analyzed their centrin-binding properties. Their affinity for centrin was measured using isothermal titration calorimetry. The chirality change in the target-derived peptides affected their ability to bind centrin in a specific manner depending on the sequence orientation of the centrin-binding motif. In contrast to L-XPC-P10, D-XPC-P10 bound C-HsCen1 in a Ca(2+)-dependent manner and to a lesser extent. D-XPC-P10 exhibited a reduced affinity for C-HsCen1 (Ka=0.064 × 10(6) M(-1)) by a factor of 2000 compared with L-XPC-P10 (Ka=132 × 10(6) M(-1)). D-peptides have a lower affinity than L-peptides for centrin, and the strength of this affinity depends on the sequence orientation of the target-derived peptides. The residual affinity observed for D-XPC suggests that the use of d-peptides represents a promising strategy for inhibiting centrin binding to its targets.
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Affiliation(s)
- Dora Grecu
- Institut Curie-Centre de Recherche, F-91405 Orsay Cédex, France; Institut National de la Santé et de la Recherche Médicale (INSERM) U759, F-91405 Orsay Cédex, France
| | - Victor Paul Raj Irudayaraj
- Institut Curie-Centre de Recherche, F-91405 Orsay Cédex, France; Institut National de la Santé et de la Recherche Médicale (INSERM) U759, F-91405 Orsay Cédex, France; UMR CNRS 7203, Paris Cédex 05, France; ENS Ecole Normale Supérieure de Paris, Paris Cédex 05, France; Université Paris 6, Paris Cédex 05, France
| | - Juan Martinez-Sanz
- Institut Curie-Centre de Recherche, F-91405 Orsay Cédex, France; Institut National de la Santé et de la Recherche Médicale (INSERM) U759, F-91405 Orsay Cédex, France; UMR9187-U1196, F-91405 Orsay Cédex, France
| | - Jean-Maurice Mallet
- UMR CNRS 7203, Paris Cédex 05, France; ENS Ecole Normale Supérieure de Paris, Paris Cédex 05, France; Université Paris 6, Paris Cédex 05, France
| | - Liliane Assairi
- Institut Curie-Centre de Recherche, F-91405 Orsay Cédex, France; Institut National de la Santé et de la Recherche Médicale (INSERM) U759, F-91405 Orsay Cédex, France.
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Abstract
Nuclear pore proteins interact dynamically with chromatin to regulate gene activities. A key question is how nucleoporin interactions mechanistically alter a gene's intranuclear position and transcriptional output. We reported recently on a direct interaction between the nuclear pore-associated TREX-2 complex and promoter-bound Mediator. This highlights how nuclear-pore associated adaptors gain regulatory access to the core transcription machinery. In this Extra View, we discuss an additional implication that arises from our work and the recent literature: how promoter elements may regulate mRNA metabolism beyond transcription initiation.
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Affiliation(s)
- Tobias Schubert
- a Max F. Perutz Laboratories , Medical University of Vienna , Vienna Biocenter Campus (VBC) , Vienna, Austria
| | - Alwin Köhler
- a Max F. Perutz Laboratories , Medical University of Vienna , Vienna Biocenter Campus (VBC) , Vienna, Austria
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Valkov E, Stewart M. 1.25 Å resolution structure of an RNA 20-mer that binds to the TREX2 complex. Acta Crystallogr F Struct Biol Commun 2015; 71:1318-21. [PMID: 26457524 PMCID: PMC4601597 DOI: 10.1107/s2053230x1501643x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 09/02/2015] [Indexed: 11/23/2022] Open
Abstract
The 1.25 Å resolution H32:R crystal structure of a 20 nt ribonucleotide that binds to the TREX-2 complex with high affinity shows a double-stranded RNA duplex arranged along a crystallographic 31 axis in which the antiparallel chains overlap by 18 nucleotides and are related by a crystallographic twofold axis. The duplex shows C-A, U-U and C-C noncanonical base pairings together with canonical Watson-Crick A-U and G-C pairs and a G-U wobble.
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Affiliation(s)
- Eugene Valkov
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, England
| | - Murray Stewart
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, England
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