1
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Zhuang Y, Guo X, Razorenova OV, Miles CE, Zhao W, Shi X. Coaching ribosome biogenesis from the nuclear periphery. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.21.597078. [PMID: 38948754 PMCID: PMC11212990 DOI: 10.1101/2024.06.21.597078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Severe invagination of the nuclear envelope is a hallmark of cancers, aging, neurodegeneration, and infections. However, the outcomes of nuclear invagination remain unclear. This work identified a new function of nuclear invagination: regulating ribosome biogenesis. With expansion microscopy, we observed frequent physical contact between nuclear invaginations and nucleoli. Surprisingly, the higher the invagination curvature, the more ribosomal RNA and pre-ribosomes are made in the contacted nucleolus. By growing cells on nanopillars that generate nuclear invaginations with desired curvatures, we can increase and decrease ribosome biogenesis. Based on this causation, we repressed the ribosome levels in breast cancer and progeria cells by growing cells on low-curvature nanopillars, indicating that overactivated ribosome biogenesis can be rescued by reshaping nuclei. Mechanistically, high-curvature nuclear invaginations reduce heterochromatin and enrich nuclear pore complexes, which promote ribosome biogenesis. We anticipate that our findings will serve as a foundation for further studies on nuclear deformation.
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Affiliation(s)
- Yinyin Zhuang
- Department of Developmental and Cell Biology, University of California, Irvine; Irvine, CA 92697, United States
| | - Xiangfu Guo
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University; Singapore 637459, Singapore
| | - Olga V. Razorenova
- Department of Molecular Biology and Biochemistry, University of California, Irvine; Irvine, CA 92697, United States
| | - Christopher E. Miles
- Department of Mathematics, University of California, Irvine; Irvine, CA 92697, United States
| | - Wenting Zhao
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University; Singapore 637459, Singapore
| | - Xiaoyu Shi
- Department of Developmental and Cell Biology, University of California, Irvine; Irvine, CA 92697, United States
- Department of Chemistry, University of California, Irvine; Irvine, CA 92697, United States
- Department of Biomedical Engineering, University of California, Irvine; Irvine, CA 92697, United States
- Lead contact
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2
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Mitterer V, Hamze H, Kunowska N, Stelzl U, Henras A, Hurt E. The RNA helicase Dbp10 coordinates assembly factor association with PTC maturation during ribosome biogenesis. Nucleic Acids Res 2024; 52:1975-1987. [PMID: 38113283 PMCID: PMC10899779 DOI: 10.1093/nar/gkad1206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 11/08/2023] [Accepted: 12/11/2023] [Indexed: 12/21/2023] Open
Abstract
During ribosome biogenesis a plethora of assembly factors and essential enzymes drive the unidirectional maturation of nascent pre-ribosomal subunits. The DEAD-box RNA helicase Dbp10 is suggested to restructure pre-ribosomal rRNA of the evolving peptidyl-transferase center (PTC) on nucleolar ribosomal 60S assembly intermediates. Here, we show that point mutations within conserved catalytic helicase-core motifs of Dbp10 yield a dominant-lethal growth phenotype. Such dbp10 mutants, which stably associate with pre-60S intermediates, impair pre-60S biogenesis at a nucleolar stage prior to the release of assembly factor Rrp14 and stable integration of late nucleolar factors such as Noc3. Furthermore, the binding of the GTPase Nug1 to particles isolated directly via mutant Dbp10 bait proteins is specifically inhibited. The N-terminal domain of Nug1 interacts with Dbp10 and the methyltransferase Spb1, whose pre-60S incorporation is also reduced in absence of functional Dbp10 resulting in decreased methylation of 25S rRNA nucleotide G2922. Our data suggest that Dbp10's helicase activity generates the necessary framework for assembly factor docking thereby permitting PTC rRNA methylation and the progression of pre-60S maturation.
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Affiliation(s)
- Valentin Mitterer
- Biochemistry Center, University of Heidelberg, 69120 Heidelberg, Germany
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Hussein Hamze
- Molecular, Cellular and Developmental Biology Unit (MCD), Center for Integrative Biology (CBI), CNRS, University of Toulouse, 31062 Toulouse, France
| | - Natalia Kunowska
- Institute of Pharmaceutical Sciences, Pharmaceutical Chemistry, University of Graz, 8010 Graz, Austria
| | - Ulrich Stelzl
- Institute of Pharmaceutical Sciences, Pharmaceutical Chemistry, University of Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
- Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Anthony K Henras
- Molecular, Cellular and Developmental Biology Unit (MCD), Center for Integrative Biology (CBI), CNRS, University of Toulouse, 31062 Toulouse, France
| | - Ed Hurt
- Biochemistry Center, University of Heidelberg, 69120 Heidelberg, Germany
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3
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LaPeruta AJ, Hedayati S, Micic J, Fitzgerald F, Kim D, Oualline G, Woolford JL. Yeast ribosome biogenesis factors Puf6 and Nog2 and ribosomal proteins uL2 and eL43 act in concert to facilitate the release of nascent large ribosomal subunits from the nucleolus. Nucleic Acids Res 2023; 51:11277-11290. [PMID: 37811893 PMCID: PMC10639061 DOI: 10.1093/nar/gkad794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 09/11/2023] [Accepted: 09/22/2023] [Indexed: 10/10/2023] Open
Abstract
Large ribosomal subunit precursors (pre-LSUs) are primarily synthesized in the nucleolus. At an undetermined step in their assembly, they are released into the nucleoplasm. Structural models of yeast pre-LSUs at various stages of assembly have been collected using cryo-EM. However, which cryo-EM model is closest to the final nucleolar intermediate of the LSU has yet to be determined. To elucidate the mechanisms of the release of pre-LSUs from the nucleolus, we assayed effects of depleting or knocking out two yeast ribosome biogenesis factors (RiBi factors), Puf6 and Nog2, and two ribosomal proteins, uL2 and eL43. These proteins function during or stabilize onto pre-LSUs between the late nucleolar stages to early nucleoplasmic stages of ribosome biogenesis. By characterizing the phenotype of these four mutants, we determined that a particle that is intermediate between the cryo-EM model State NE1 and State NE2 likely represents the final nucleolar assembly intermediate of the LSU. We conclude that the release of the RiBi factors Nip7, Nop2 and Spb1 and the subsequent stabilization of rRNA domains IV and V may be key triggers for the release of pre-LSUs from the nucleolus.
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Affiliation(s)
- Amber J LaPeruta
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Stefanie Hedayati
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Jelena Micic
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Fiona Fitzgerald
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - David Kim
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Grace Oualline
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - John L Woolford
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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4
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Fisher JG, Doyle ADP, Graham LV, Sonar S, Sale B, Henderson I, Del Rio L, Johnson PWM, Landesman Y, Cragg MS, Forconi F, Walker CJ, Khakoo SI, Blunt MD. XPO1 inhibition sensitises CLL cells to NK cell mediated cytotoxicity and overcomes HLA-E expression. Leukemia 2023; 37:2036-2049. [PMID: 37528310 PMCID: PMC10539165 DOI: 10.1038/s41375-023-01984-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 07/03/2023] [Accepted: 07/21/2023] [Indexed: 08/03/2023]
Abstract
The first-in-class inhibitor of exportin-1 (XPO1) selinexor is currently under clinical investigation in combination with the BTK inhibitor ibrutinib for patients with chronic lymphocytic leukaemia (CLL) or non-Hodgkin lymphoma. Selinexor induces apoptosis of tumour cells through nuclear retention of tumour suppressor proteins and has also recently been described to modulate natural killer (NK) cell and T cell cytotoxicity against lymphoma cells. Here, we demonstrate that XPO1 inhibition enhances NK cell effector function against primary CLL cells via downregulation of HLA-E and upregulation of TRAIL death receptors DR4 and DR5. Furthermore, selinexor potentiates NK cell activation against CLL cells in combination with several approved treatments; acalabrutinib, rituximab and obinutuzumab. We further demonstrate that lymph node associated signals (IL-4 + CD40L) inhibit NK cell activation against CLL cells via upregulation of HLA-E, and that inhibition of XPO1 can overcome this protective effect. These findings allow for the design of more efficacious combination strategies to harness NK cell effector functions against CLL.
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Affiliation(s)
- Jack G Fisher
- School of Clinical and Experimental Sciences, University of Southampton, Southampton, UK
| | - Amber D P Doyle
- School of Clinical and Experimental Sciences, University of Southampton, Southampton, UK
| | - Lara V Graham
- School of Clinical and Experimental Sciences, University of Southampton, Southampton, UK
| | - Shreyanshi Sonar
- School of Clinical and Experimental Sciences, University of Southampton, Southampton, UK
| | - Ben Sale
- School of Cancer Sciences, University of Southampton, Southampton, UK
| | - Isla Henderson
- School of Cancer Sciences, University of Southampton, Southampton, UK
| | - Luis Del Rio
- School of Cancer Sciences, University of Southampton, Southampton, UK
| | - Peter W M Johnson
- School of Cancer Sciences, University of Southampton, Southampton, UK
| | | | - Mark S Cragg
- School of Cancer Sciences, University of Southampton, Southampton, UK
- Antibody and Vaccine Group, Centre for Cancer Immunology, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Francesco Forconi
- School of Cancer Sciences, University of Southampton, Southampton, UK
- Haematology Department, Cancer Care Directorate, University Hospital Southampton NHS Trust, Southampton, UK
| | | | - Salim I Khakoo
- School of Clinical and Experimental Sciences, University of Southampton, Southampton, UK
| | - Matthew D Blunt
- School of Clinical and Experimental Sciences, University of Southampton, Southampton, UK.
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5
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Junod SL, Tingey M, Kelich JM, Goryaynov A, Herbine K, Yang W. Dynamics of nuclear export of pre-ribosomal subunits revealed by high-speed single-molecule microscopy in live cells. iScience 2023; 26:107445. [PMID: 37599825 PMCID: PMC10433129 DOI: 10.1016/j.isci.2023.107445] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 06/24/2023] [Accepted: 07/18/2023] [Indexed: 08/22/2023] Open
Abstract
We present a study on the nuclear export efficiency and time of pre-ribosomal subunits in live mammalian cells, using high-speed single-molecule tracking and single-molecule fluorescence resonance energy transfer techniques. Our findings reveal that pre-ribosomal particles exhibit significantly higher nuclear export efficiency compared to other large cargos like mRNAs, with around two-thirds of interactions between the pre-60S or pre-40S and the nuclear pore complexes (NPCs) resulting in successful export to the cytoplasm. We also demonstrate that nuclear transport receptor (NTR) chromosomal maintenance 1 (CRM1) plays a crucial role in nuclear export efficiency, with pre-60S and pre-40S particle export efficiency decreasing by 11-17-fold when CRM1 is inhibited. Our results suggest that multiple copies of CRM1 work cooperatively to chaperone pre-ribosomal subunits through the NPC, thus increasing export efficiency and decreasing export time. Significantly, this cooperative NTR mechanism extends beyond pre-ribosomal subunits, as evidenced by the enhanced nucleocytoplasmic transport of proteins.
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Affiliation(s)
- Samuel L. Junod
- Department of Biology, Temple University, Philadelphia, PA, USA
| | - Mark Tingey
- Department of Biology, Temple University, Philadelphia, PA, USA
| | | | | | - Karl Herbine
- Department of Biology, Temple University, Philadelphia, PA, USA
| | - Weidong Yang
- Department of Biology, Temple University, Philadelphia, PA, USA
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6
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Li Z, Chen S, Zhao L, Huang G, Xu H, Yang X, Wang P, Gao N, Sui SF. Nuclear export of pre-60S particles through the nuclear pore complex. Nature 2023:10.1038/s41586-023-06128-y. [PMID: 37258668 DOI: 10.1038/s41586-023-06128-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 04/25/2023] [Indexed: 06/02/2023]
Abstract
The nuclear pore complex (NPC) is the bidirectional gate that mediates the exchange of macromolecules or their assemblies between nucleus and cytoplasm1-3. The assembly intermediates of the ribosomal subunits, pre-60S and pre-40S particles, are among the largest cargoes of the NPC and the export of these gigantic ribonucleoproteins requires numerous export factors4,5. Here we report the cryo-electron microscopy structure of native pre-60S particles trapped in the channel of yeast NPCs. In addition to known assembly factors, multiple factors with export functions are also included in the structure. These factors in general bind to either the flexible regions or subunit interface of the pre-60S particle, and virtually form many anchor sites for NPC binding. Through interactions with phenylalanine-glycine (FG) repeats from various nucleoporins of NPC, these factors collectively facilitate the passage of the pre-60S particle through the central FG repeat network of the NPC. Moreover, in silico analysis of the axial and radial distribution of pre-60S particles within the NPC shows that a single NPC can take up to four pre-60S particles simultaneously, and pre-60S particles are enriched in the inner ring regions close to the wall of the NPC with the solvent-exposed surface facing the centre of the nuclear pore. Our data suggest a translocation model for the export of pre-60S particles through the NPC.
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Affiliation(s)
- Zongqiang Li
- School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
| | - Shuaijiabin Chen
- School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
| | - Liang Zhao
- School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
| | - Guoqiang Huang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
| | - Huiqin Xu
- School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Xiaoyun Yang
- School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Peiyi Wang
- Cryo-EM Center, Southern University of Science and Technology, Shenzhen, China
| | - Ning Gao
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Sen-Fang Sui
- School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China.
- Cryo-EM Center, Southern University of Science and Technology, Shenzhen, China.
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7
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Dörner K, Ruggeri C, Zemp I, Kutay U. Ribosome biogenesis factors-from names to functions. EMBO J 2023; 42:e112699. [PMID: 36762427 PMCID: PMC10068337 DOI: 10.15252/embj.2022112699] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 12/13/2022] [Accepted: 01/19/2023] [Indexed: 02/11/2023] Open
Abstract
The assembly of ribosomal subunits is a highly orchestrated process that involves a huge cohort of accessory factors. Most eukaryotic ribosome biogenesis factors were first identified by genetic screens and proteomic approaches of pre-ribosomal particles in Saccharomyces cerevisiae. Later, research on human ribosome synthesis not only demonstrated that the requirement for many of these factors is conserved in evolution, but also revealed the involvement of additional players, reflecting a more complex assembly pathway in mammalian cells. Yet, it remained a challenge for the field to assign a function to many of the identified factors and to reveal their molecular mode of action. Over the past decade, structural, biochemical, and cellular studies have largely filled this gap in knowledge and led to a detailed understanding of the molecular role that many of the players have during the stepwise process of ribosome maturation. Such detailed knowledge of the function of ribosome biogenesis factors will be key to further understand and better treat diseases linked to disturbed ribosome assembly, including ribosomopathies, as well as different types of cancer.
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Affiliation(s)
- Kerstin Dörner
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland.,Molecular Life Sciences Ph.D. Program, Zurich, Switzerland
| | - Chiara Ruggeri
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland.,RNA Biology Ph.D. Program, Zurich, Switzerland
| | - Ivo Zemp
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
| | - Ulrike Kutay
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
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8
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Tingey M, Li Y, Yu W, Young A, Yang W. Spelling out the roles of individual nucleoporins in nuclear export of mRNA. Nucleus 2022; 13:170-193. [PMID: 35593254 PMCID: PMC9132428 DOI: 10.1080/19491034.2022.2076965] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 05/08/2022] [Accepted: 05/09/2022] [Indexed: 11/01/2022] Open
Abstract
The Nuclear Pore Complex (NPC) represents a critical passage through the nuclear envelope for nuclear import and export that impacts nearly every cellular process at some level. Recent technological advances in the form of Auxin Inducible Degron (AID) strategies and Single-Point Edge-Excitation sub-Diffraction (SPEED) microscopy have enabled us to provide new insight into the distinct functions and roles of nuclear basket nucleoporins (Nups) upon nuclear docking and export for mRNAs. In this paper, we provide a review of our recent findings as well as an assessment of new techniques, updated models, and future perspectives in the studies of mRNA's nuclear export.
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Affiliation(s)
- Mark Tingey
- Department of Biology, Temple University, Philadelphia, Pennsylvania, USA
| | - Yichen Li
- Department of Genetics, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Wenlan Yu
- Department of Biology, Temple University, Philadelphia, Pennsylvania, USA
| | - Albert Young
- Department of Biology, Temple University, Philadelphia, Pennsylvania, USA
| | - Weidong Yang
- Department of Biology, Temple University, Philadelphia, Pennsylvania, USA
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9
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Sending the message: specialized RNA export mechanisms in trypanosomes. Trends Parasitol 2022; 38:854-867. [PMID: 36028415 PMCID: PMC9894534 DOI: 10.1016/j.pt.2022.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 07/25/2022] [Accepted: 07/25/2022] [Indexed: 02/04/2023]
Abstract
Export of RNA from the nucleus is essential for all eukaryotic cells and has emerged as a major step in the control of gene expression. mRNA molecules are required to complete a complex series of processing events and pass a quality control system to protect the cytoplasm from the translation of aberrant proteins. Many of these events are highly conserved across eukaryotes, reflecting their ancient origin, but significant deviation from a canonical pathway as described from animals and fungi has emerged in the trypanosomatids. With significant implications for the mechanisms that control gene expression and hence differentiation, responses to altered environments and fitness as a parasite, these deviations may also reveal additional, previously unsuspected, mRNA export pathways.
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10
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Moraleva AA, Deryabin AS, Rubtsov YP, Rubtsova MP, Dontsova OA. Eukaryotic Ribosome Biogenesis: The 60S Subunit. Acta Naturae 2022; 14:39-49. [PMID: 35925480 PMCID: PMC9307984 DOI: 10.32607/actanaturae.11541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 02/11/2022] [Indexed: 11/20/2022] Open
Abstract
Ribosome biogenesis is consecutive coordinated maturation of ribosomal precursors in the nucleolus, nucleoplasm, and cytoplasm. The formation of mature ribosomal subunits involves hundreds of ribosomal biogenesis factors that ensure ribosomal RNA processing, tertiary structure, and interaction with ribosomal proteins. Although the main features and stages of ribosome biogenesis are conservative among different groups of eukaryotes, this process in human cells has become more complicated due to the larger size of the ribosomes and pre-ribosomes and intricate regulatory pathways affecting their assembly and function. Many of the factors involved in the biogenesis of human ribosomes have been identified using genome-wide screening based on RNA interference. A previous part of this review summarized recent data on the processing of the primary rRNA transcript and compared the maturation of the small 40S subunit in yeast and human cells. This part of the review focuses on the biogenesis of the large 60S subunit of eukaryotic ribosomes.
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Affiliation(s)
- A. A. Moraleva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, 117997 Russia
| | - A. S. Deryabin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, 117997 Russia
| | - Yu. P. Rubtsov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, 117997 Russia
| | - M. P. Rubtsova
- Lomonosov Moscow State University, Faculty of Chemistry, Moscow, 119991 Russia
| | - O. A. Dontsova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, 117997 Russia
- Lomonosov Moscow State University, Faculty of Chemistry, Moscow, 119991 Russia
- Skolkovo Institute of Science and Technology, Moscow, 121205 Russia
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11
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Oborská-Oplová M, Fischer U, Altvater M, Panse VG. Eukaryotic Ribosome assembly and Nucleocytoplasmic Transport. Methods Mol Biol 2022; 2533:99-126. [PMID: 35796985 PMCID: PMC9761919 DOI: 10.1007/978-1-0716-2501-9_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The process of eukaryotic ribosome assembly stretches across the nucleolus, the nucleoplasm and the cytoplasm, and therefore relies on efficient nucleocytoplasmic transport. In yeast, the import machinery delivers ~140,000 ribosomal proteins every minute to the nucleus for ribosome assembly. At the same time, the export machinery facilitates translocation of ~2000 pre-ribosomal particles every minute through ~200 nuclear pore complexes (NPC) into the cytoplasm. Eukaryotic ribosome assembly also requires >200 conserved assembly factors, which transiently associate with pre-ribosomal particles. Their site(s) of action on maturing pre-ribosomes are beginning to be elucidated. In this chapter, we outline protocols that enable rapid biochemical isolation of pre-ribosomal particles for single particle cryo-electron microscopy (cryo-EM) and in vitro reconstitution of nuclear transport processes. We discuss cell-biological and genetic approaches to investigate how the ribosome assembly and the nucleocytoplasmic transport machineries collaborate to produce functional ribosomes.
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Affiliation(s)
- Michaela Oborská-Oplová
- Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Ute Fischer
- Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
| | | | - Vikram Govind Panse
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland.
- Faculty of Science, University of Zurich, Zurich, Switzerland.
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12
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Nuclear export of the pre-60S ribosomal subunit through single nuclear pores observed in real time. Nat Commun 2021; 12:6211. [PMID: 34707094 PMCID: PMC8551241 DOI: 10.1038/s41467-021-26323-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 09/02/2021] [Indexed: 11/08/2022] Open
Abstract
Ribosomal biogenesis has been studied by biochemical, genetic and electron microscopic approaches, but live cell data on the in vivo kinetics are still missing. Here we analyse the export kinetics of the large ribosomal subunit (pre-60S particle) through single NPCs in human cells. We established a stable cell line co-expressing Halo-tagged eIF6 and GFP-fused NTF2 to simultaneously label pre-60S particles and NPCs, respectively. By combining single molecule tracking and super resolution confocal microscopy we visualize the dynamics of single pre-60S particles during export through single NPCs. For export events, maximum particle accumulation is found in the centre of the pore, while unsuccessful export terminates within the nuclear basket. The export has a single rate limiting step and a duration of ∼24 milliseconds. Only about 1/3 of attempted export events are successful. Our results show that the mass flux through a single NPC can reach up to ~125 MDa·s-1 in vivo.
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13
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Semmelink MFW, Steen A, Veenhoff LM. Measuring and Interpreting Nuclear Transport in Neurodegenerative Disease-The Example of C9orf72 ALS. Int J Mol Sci 2021; 22:9217. [PMID: 34502125 PMCID: PMC8431710 DOI: 10.3390/ijms22179217] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/13/2021] [Accepted: 08/18/2021] [Indexed: 11/25/2022] Open
Abstract
Transport from and into the nucleus is essential to all eukaryotic life and occurs through the nuclear pore complex (NPC). There are a multitude of data supporting a role for nuclear transport in neurodegenerative diseases, but actual transport assays in disease models have provided diverse outcomes. In this review, we summarize how nuclear transport works, which transport assays are available, and what matters complicate the interpretation of their results. Taking a specific type of ALS caused by mutations in C9orf72 as an example, we illustrate these complications, and discuss how the current data do not firmly answer whether the kinetics of nucleocytoplasmic transport are altered. Answering this open question has far-reaching implications, because a positive answer would imply that widespread mislocalization of proteins occurs, far beyond the reported mislocalization of transport reporters, and specific proteins such as FUS, or TDP43, and thus presents a challenge for future research.
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Affiliation(s)
| | | | - Liesbeth M. Veenhoff
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands; (M.F.W.S.); (A.S.)
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14
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Shen Q, Wang YE, Palazzo AF. Crosstalk between nucleocytoplasmic trafficking and the innate immune response to viral infection. J Biol Chem 2021; 297:100856. [PMID: 34097873 PMCID: PMC8254040 DOI: 10.1016/j.jbc.2021.100856] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 05/24/2021] [Accepted: 06/03/2021] [Indexed: 12/16/2022] Open
Abstract
The nuclear pore complex is the sole gateway connecting the nucleoplasm and cytoplasm. In humans, the nuclear pore complex is one of the largest multiprotein assemblies in the cell, with a molecular mass of ∼110 MDa and consisting of 8 to 64 copies of about 34 different nuclear pore proteins, termed nucleoporins, for a total of 1000 subunits per pore. Trafficking events across the nuclear pore are mediated by nuclear transport receptors and are highly regulated. The nuclear pore complex is also used by several RNA viruses and almost all DNA viruses to access the host cell nucleoplasm for replication. Viruses hijack the nuclear pore complex, and nuclear transport receptors, to access the nucleoplasm where they replicate. In addition, the nuclear pore complex is used by the cell innate immune system, a network of signal transduction pathways that coordinates the first response to foreign invaders, including viruses and other pathogens. Several branches of this response depend on dynamic signaling events that involve the nuclear translocation of downstream signal transducers. Mounting evidence has shown that these signaling cascades, especially those steps that involve nucleocytoplasmic trafficking events, are targeted by viruses so that they can evade the innate immune system. This review summarizes how nuclear pore proteins and nuclear transport receptors contribute to the innate immune response and highlights how viruses manipulate this cellular machinery to favor infection. A comprehensive understanding of nuclear pore proteins in antiviral innate immunity will likely contribute to the development of new antiviral therapeutic strategies.
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Affiliation(s)
- Qingtang Shen
- School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China.
| | - Yifan E Wang
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Alexander F Palazzo
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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15
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Reza AMMT, Yuan YG. microRNAs Mediated Regulation of the Ribosomal Proteins and its Consequences on the Global Translation of Proteins. Cells 2021; 10:110. [PMID: 33435549 PMCID: PMC7827472 DOI: 10.3390/cells10010110] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 12/14/2020] [Indexed: 12/23/2022] Open
Abstract
Ribosomal proteins (RPs) are mostly derived from the energy-consuming enzyme families such as ATP-dependent RNA helicases, AAA-ATPases, GTPases and kinases, and are important structural components of the ribosome, which is a supramolecular ribonucleoprotein complex, composed of Ribosomal RNA (rRNA) and RPs, coordinates the translation and synthesis of proteins with the help of transfer RNA (tRNA) and other factors. Not all RPs are indispensable; in other words, the ribosome could be functional and could continue the translation of proteins instead of lacking in some of the RPs. However, the lack of many RPs could result in severe defects in the biogenesis of ribosomes, which could directly influence the overall translation processes and global expression of the proteins leading to the emergence of different diseases including cancer. While microRNAs (miRNAs) are small non-coding RNAs and one of the potent regulators of the post-transcriptional gene expression, miRNAs regulate gene expression by targeting the 3' untranslated region and/or coding region of the messenger RNAs (mRNAs), and by interacting with the 5' untranslated region, and eventually finetune the expression of approximately one-third of all mammalian genes. Herein, we highlighted the significance of miRNAs mediated regulation of RPs coding mRNAs in the global protein translation.
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Affiliation(s)
- Abu Musa Md Talimur Reza
- Jiangsu Co-Innovation Center of Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China;
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Yu-Guo Yuan
- Jiangsu Co-Innovation Center of Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China;
- Jiangsu Key Laboratory of Zoonosis/Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
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16
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Mutational Analysis of the Nsa2 N-Terminus Reveals Its Essential Role in Ribosomal 60S Subunit Assembly. Int J Mol Sci 2020; 21:ijms21239108. [PMID: 33266193 PMCID: PMC7730687 DOI: 10.3390/ijms21239108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 11/23/2020] [Accepted: 11/25/2020] [Indexed: 11/23/2022] Open
Abstract
The ribosome assembly factor Nsa2 is part of the Rea1-Rsa4-Nsa2 interconnected relay on nuclear pre-60S particles that is essential for 60S ribosome biogenesis. Cryo-EM structures depict Nsa2 docked via its C-terminal β-barrel domain to nuclear pre-60S particles, whereas the extended N-terminus, consisting of three α-helical segments, meanders between various 25S rRNA helices with the extreme N-terminus in close vicinity to the Nog1 GTPase center. Here, we tested whether this unappreciated proximity between Nsa2 and Nog1 is of functional importance. Our findings demonstrate that a conservative mutation, Nsa2 Q3N, abolished cell growth and impaired 60S biogenesis. Subsequent genetic and biochemical analyses verified that the Nsa2 N-terminus is required to target Nsa2 to early pre-60S particles. However, overexpression of the Nsa2 N-terminus abolished cytoplasmic recycling of the Nog1 GTPase, and both Nog1 and the Nsa2-N (1-58) construct, but not the respective Nsa2-N (1-58) Q3N mutant, were found arrested on late cytoplasmic pre-60S particles. These findings point to specific roles of the different Nsa2 domains for 60S ribosome biogenesis.
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17
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Guha S, Bhaumik SR. Viral regulation of mRNA export with potentials for targeted therapy. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1864:194655. [PMID: 33246183 DOI: 10.1016/j.bbagrm.2020.194655] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 10/15/2020] [Accepted: 11/05/2020] [Indexed: 12/12/2022]
Abstract
Eukaryotic gene expression begins with transcription in the nucleus to synthesize mRNA (messenger RNA), which is subsequently exported to the cytoplasm for translation to protein. Like transcription and translation, mRNA export is an important regulatory step of eukaryotic gene expression. Various factors are involved in regulating mRNA export, and thus gene expression. Intriguingly, some of these factors interact with viral proteins, and such interactions interfere with mRNA export of the host cell, favoring viral RNA export. Hence, viruses hijack host mRNA export machinery for export of their own RNAs from nucleus to cytoplasm for translation to proteins for viral life cycle, suppressing host mRNA export (and thus host gene expression and immune/antiviral response). Therefore, the molecules that can impair the interactions of these mRNA export factors with viral proteins could emerge as antiviral therapeutic agents to suppress viral RNA transport and enhance host mRNA export, thereby promoting host gene expression and immune response. Thus, there has been a number of studies to understand how virus hijacks mRNA export machinery in suppressing host gene expression and promoting its own RNA export to the cytoplasm for translation to proteins required for viral replication/assembly/life cycle towards developing targeted antiviral therapies, as concisely described here.
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Affiliation(s)
- Shalini Guha
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Sukesh R Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA.
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18
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Jaramillo-Ramírez J, Marcial-Bazaldua N, Sánchez-Puig N. Characterisation of the interaction of guanine nucleotides with ribosomal GTPase Lsg1. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1869:140538. [PMID: 32916301 DOI: 10.1016/j.bbapap.2020.140538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 08/06/2020] [Accepted: 09/03/2020] [Indexed: 10/23/2022]
Abstract
Ribosome biogenesis in eukaryotes requires the participation of several transactivation factors that are involved in the modification, assembly, transport and quality control of the ribosomal subunits. One of these factors is the Large subunit GTPase 1 (Lsg1), a protein that acts as the release factor for the export adaptor named Nonsense-mediated mRNA decay 3 protein (Nmd3) and facilitates the incorporation of the last structural protein uL16 into the 60S subunit. Here, we characterised the recombinant yeast Lsg1 and studied its catalysis and binding properties for guanine nucleotides. We described the interaction of Lsg1 with guanine nucleotides alone and in the presence of the complex Nmd3•60S using fluorescence spectroscopy. Lsg1 has a greater affinity for GTP than for GDP suggesting that in the cell cytoplasm it exists mainly bound to the former. In the presence of 60S subunits loaded with Nmd3, the affinity of Lsg1 for both nucleotides increases but to a larger extent towards GTP. From this observation together with the excess of GTP present in the cytoplasm of exponentially growing cells over that of GDP, we can infer that the pre-ribosomal particle composed by Nmd3•60S acts as a GTP Stabilising Factor for Lsg1. Additionally, Lsg1 undergoes different conformational changes depending on its binding partner or the guanine nucleotides it interacts with. Steady-state kinetic analysis of free Lsg1 indicated slow GTP hydrolysis with values of kcat 1 min-1 and Km of 34 μM.
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Affiliation(s)
- Juliana Jaramillo-Ramírez
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Ciudad de México 04510, Mexico
| | - Nancy Marcial-Bazaldua
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Ciudad de México 04510, Mexico
| | - Nuria Sánchez-Puig
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Ciudad de México 04510, Mexico..
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19
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Abe T, Nagai R, Shimazaki S, Kondo S, Nishimura S, Sakaguchi Y, Suzuki T, Imataka H, Tomita K, Takeuchi-Tomita N. In vitro yeast reconstituted translation system reveals function of eIF5A for synthesis of long polypeptide. J Biochem 2020; 167:451-462. [PMID: 32053170 DOI: 10.1093/jb/mvaa022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 02/03/2020] [Indexed: 12/19/2022] Open
Abstract
We have recently developed an in vitro yeast reconstituted translation system, which is capable of synthesizing long polypeptides. Utilizing the system, we examined the role of eIF5A and its hypusine modification in translating polyproline sequence within long open reading frames. We found that polyproline motif inserted at the internal position of the protein arrests translation exclusively at low Mg2+ concentrations, and peptidylpolyproline-tRNA intrinsically destabilizes 80S ribosomes. We demonstrate that unmodified eIF5A essentially resolves such ribosome stalling; however, the hypusine modification drastically stimulates ability of eIF5A to rescue polyproline-mediated ribosome stalling and is particularly important for the efficient translation of the N-terminal or long internal polyproline motifs.
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Affiliation(s)
- Taisho Abe
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Riku Nagai
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Shunta Shimazaki
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Shunta Kondo
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Satoshi Nishimura
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Yuriko Sakaguchi
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tsutomu Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hiroaki Imataka
- Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, Himeji 671-2201, Japan
| | - Kozo Tomita
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Nono Takeuchi-Tomita
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
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20
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Into the basket and beyond: the journey of mRNA through the nuclear pore complex. Biochem J 2020; 477:23-44. [DOI: 10.1042/bcj20190132] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/28/2019] [Accepted: 12/10/2019] [Indexed: 02/06/2023]
Abstract
The genetic information encoded in nuclear mRNA destined to reach the cytoplasm requires the interaction of the mRNA molecule with the nuclear pore complex (NPC) for the process of mRNA export. Numerous proteins have important roles in the transport of mRNA out of the nucleus. The NPC embedded in the nuclear envelope is the port of exit for mRNA and is composed of ∼30 unique proteins, nucleoporins, forming the distinct structures of the nuclear basket, the pore channel and cytoplasmic filaments. Together, they serve as a rather stationary complex engaged in mRNA export, while a variety of soluble protein factors dynamically assemble on the mRNA and mediate the interactions of the mRNA with the NPC. mRNA export factors are recruited to and dissociate from the mRNA at the site of transcription on the gene, during the journey through the nucleoplasm and at the nuclear pore at the final stages of export. In this review, we present the current knowledge derived from biochemical, molecular, structural and imaging studies, to develop a high-resolution picture of the many events that culminate in the successful passage of the mRNA out of the nucleus.
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21
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Musalgaonkar S, Black JJ, Johnson AW. The L1 stalk is required for efficient export of nascent large ribosomal subunits in yeast. RNA (NEW YORK, N.Y.) 2019; 25:1549-1560. [PMID: 31439809 PMCID: PMC6795138 DOI: 10.1261/rna.071811.119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 08/08/2019] [Indexed: 06/02/2023]
Abstract
The ribosomal protein Rpl1 (uL1 in universal nomenclature) is essential in yeast and constitutes part of the L1 stalk which interacts with E site ligands on the ribosome. Structural studies of nascent pre-60S complexes in yeast have shown that a domain of the Crm1-dependent nuclear export adapter Nmd3, binds in the E site and interacts with Rpl1, inducing closure of the L1 stalk. Based on this observation, we decided to reinvestigate the role of the L1 stalk in nuclear export of pre-60S subunits despite previous work showing that Rpl1-deficient ribosomes are exported from the nucleus and engage in translation. Large cargoes, such as ribosomal subunits, require multiple export factors to facilitate their transport through the nuclear pore complex. Here, we show that pre-60S subunits lacking Rpl1 or truncated for the RNA of the L1 stalk are exported inefficiently. Surprisingly, this is not due to a measurable defect in the recruitment of Nmd3 but appears to result from inefficient recruitment of the Mex67-Mtr2 heterodimer.
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Affiliation(s)
- Sharmishtha Musalgaonkar
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Joshua J Black
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Arlen W Johnson
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
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22
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Rink C, Williams N. Unique Interactions of the Nuclear Export Receptors TbMex67 and TbMtr2 with Components of the 5S Ribonuclear Particle in Trypanosoma brucei. mSphere 2019; 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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 07/29/2019] [Indexed: 01/24/2023] Open
Abstract
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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Affiliation(s)
- Constance Rink
- Department of Microbiology and Immunology, University at Buffalo, Buffalo, New York, USA
| | - Noreen Williams
- Department of Microbiology and Immunology, University at Buffalo, Buffalo, New York, USA
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23
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Pantazi A, Quintanilla A, Hari P, Tarrats N, Parasyraki E, Dix FL, Patel J, Chandra T, Acosta JC, Finch AJ. Inhibition of the 60S ribosome biogenesis GTPase LSG1 causes endoplasmic reticular disruption and cellular senescence. Aging Cell 2019; 18:e12981. [PMID: 31148378 PMCID: PMC6612703 DOI: 10.1111/acel.12981] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 04/06/2019] [Accepted: 04/28/2019] [Indexed: 01/07/2023] Open
Abstract
Cellular senescence is triggered by diverse stimuli and is characterized by long-term growth arrest and secretion of cytokines and chemokines (termed the SASP-senescence-associated secretory phenotype). Senescence can be organismally beneficial as it can prevent the propagation of damaged or mutated clones and stimulate their clearance by immune cells. However, it has recently become clear that senescence also contributes to the pathophysiology of aging through the accumulation of damaged cells within tissues. Here, we describe that inhibition of the reaction catalysed by LSG1, a GTPase involved in the biogenesis of the 60S ribosomal subunit, leads to a robust induction of cellular senescence. Perhaps surprisingly, this was not due to ribosome depletion or translational insufficiency, but rather through perturbation of endoplasmic reticulum homeostasis and a dramatic upregulation of the cholesterol biosynthesis pathway. The underlying transcriptomic signature is shared with several other forms of senescence, and the cholesterol biosynthesis genes contribute to the cell cycle arrest in oncogene-induced senescence. Furthermore, targeting of LSG1 resulted in amplification of the cholesterol/ER signature and restoration of a robust cellular senescence response in transformed cells, suggesting potential therapeutic uses of LSG1 inhibition.
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Affiliation(s)
- Asimina Pantazi
- Cancer Research UK Edinburgh Centre, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghUK
| | - Andrea Quintanilla
- Cancer Research UK Edinburgh Centre, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghUK
| | - Priya Hari
- Cancer Research UK Edinburgh Centre, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghUK
| | - Nuria Tarrats
- Cancer Research UK Edinburgh Centre, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghUK
| | - Eleftheria Parasyraki
- Cancer Research UK Edinburgh Centre, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghUK
| | - Flora L. Dix
- Cancer Research UK Edinburgh Centre, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghUK
| | - Jaiyogesh Patel
- Cancer Research UK Edinburgh Centre, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghUK
| | - Tamir Chandra
- MRC Human Genetics Unit, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghUK
| | - Juan Carlos Acosta
- Cancer Research UK Edinburgh Centre, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghUK
| | - Andrew J. Finch
- Cancer Research UK Edinburgh Centre, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghUK
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24
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The chemical diversity of RNA modifications. Biochem J 2019; 476:1227-1245. [PMID: 31028151 DOI: 10.1042/bcj20180445] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/25/2019] [Accepted: 02/26/2019] [Indexed: 12/16/2022]
Abstract
Nucleic acid modifications in DNA and RNA ubiquitously exist among all the three kingdoms of life. This trait significantly broadens the genome diversity and works as an important means of gene transcription regulation. Although mammalian systems have limited types of DNA modifications, over 150 different RNA modification types have been identified, with a wide variety of chemical diversities. Most modifications occur on transfer RNA and ribosomal RNA, however many of the modifications also occur on other types of RNA species including mammalian mRNA and small nuclear RNA, where they are essential for many biological roles, including developmental processes and stem cell differentiation. These post-transcriptional modifications are enzymatically installed and removed in a site-specific manner by writer and eraser proteins respectively, while reader proteins can interpret modifications and transduce the signal for downstream functions. Dysregulation of mRNA modifications manifests as disease states, including multiple types of human cancer. In this review, we will introduce the chemical features and biological functions of these modifications in the coding and non-coding RNA species.
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25
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Zhou Y, Musalgaonkar S, Johnson AW, Taylor DW. Tightly-orchestrated rearrangements govern catalytic center assembly of the ribosome. Nat Commun 2019; 10:958. [PMID: 30814529 PMCID: PMC6393466 DOI: 10.1038/s41467-019-08880-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 02/01/2019] [Indexed: 11/24/2022] Open
Abstract
The catalytic activity of the ribosome is mediated by RNA, yet proteins are essential for the function of the peptidyl transferase center (PTC). In eukaryotes, final assembly of the PTC occurs in the cytoplasm by insertion of the ribosomal protein Rpl10 (uL16). We determine structures of six intermediates in late nuclear and cytoplasmic maturation of the large subunit that reveal a tightly-choreographed sequence of protein and RNA rearrangements controlling the insertion of Rpl10. We also determine the structure of the biogenesis factor Yvh1 and show how it promotes assembly of the P stalk, a critical element for recruitment of GTPases that drive translation. Together, our structures provide a blueprint for final assembly of a functional ribosome. In eukaryotes, ribosome biogenesis culminates in the cytoplasm with the maturation of the peptidyl transfer center (PTC). Here the authors describe several structures of intermediates in late nuclear and cytoplasmic maturation of the large ribosomal subunit that reveal the tightly-choreographed sequence of protein and RNA rearrangements that lead to the completion of the PTC.
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Affiliation(s)
- Yi Zhou
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA
| | | | - Arlen W Johnson
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA. .,Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, 78712, USA.
| | - David W Taylor
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA.,Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, 78712, USA.,Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX, 78712, USA.,LIVESTRONG Cancer Institutes, Dell Medical School, Austin, TX, 78712, USA
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26
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Abstract
Ribosomes, which synthesize the proteins of a cell, comprise ribosomal RNA and ribosomal proteins, which coassemble hierarchically during a process termed ribosome biogenesis. Historically, biochemical and molecular biology approaches have revealed how preribosomal particles form and mature in consecutive steps, starting in the nucleolus and terminating after nuclear export into the cytoplasm. However, only recently, due to the revolution in cryo-electron microscopy, could pseudoatomic structures of different preribosomal particles be obtained. Together with in vitro maturation assays, these findings shed light on how nascent ribosomes progress stepwise along a dynamic biogenesis pathway. Preribosomes assemble gradually, chaperoned by a myriad of assembly factors and small nucleolar RNAs, before they reach maturity and enter translation. This information will lead to a better understanding of how ribosome synthesis is linked to other cellular pathways in humans and how it can cause diseases, including cancer, if disturbed.
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Affiliation(s)
- Jochen Baßler
- Biochemistry Center, University of Heidelberg, 69120 Heidelberg, Germany; ,
| | - Ed Hurt
- Biochemistry Center, University of Heidelberg, 69120 Heidelberg, Germany; ,
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27
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Carotenuto R, Tussellino M. Xenopus laevis oocyte as a model for the study of the cytoskeleton. C R Biol 2018; 341:219-227. [PMID: 29705198 DOI: 10.1016/j.crvi.2018.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 04/06/2018] [Indexed: 11/28/2022]
Abstract
At the beginning of diplotene, the oocyte of Xenopus laevis is a cell of about 10-20 microns destined to increase 10,000-fold its size when the oocyte becomes filled with yolk platelets and has accumulated a great number of pigment granules in a half of its periphery. Its internal architecture is gradually accomplished during growth because of several factors, especially because of cytoskeletal changes. In the fully-grown oocyte, the cytoskeleton appears to sustain the eccentrically located germinal vesicle through arms radiating from the cortex to the germinal vesicle, a unique organization not to be found in other Amphibians. In this report, we summarized and analysed steps of cytoskeletal proteins and related mRNAs organization and function throughout diplotene stage, highlighting our studies in this animal model. The cytoskeletal proteins appear to exploit their activity with respect to ribosomal 60S subunit maturation and during translation. Most importantly, the polarity of the oocyte is achieved through a sophisticated and highly organized localization of mRNAs and cytoskeletal proteins in one side of the cell. This asymmetry will start the construction of the oocyte polarity that is instrumental for determining the characteristic of this cell, which will become an embryo. Moreover, in the same time membrane composition, conditioned by the underlying cytoskeletal organization, will acquire the prerequisites for sperm binding and fusion.
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Affiliation(s)
- Rosa Carotenuto
- Department of Biology, University of Naples Federico II, Napoli, Italy.
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28
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Warren AJ. Molecular basis of the human ribosomopathy Shwachman-Diamond syndrome. Adv Biol Regul 2018; 67:109-127. [PMID: 28942353 PMCID: PMC6710477 DOI: 10.1016/j.jbior.2017.09.002] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 09/05/2017] [Indexed: 01/05/2023]
Abstract
Mutations that target the ubiquitous process of ribosome assembly paradoxically cause diverse tissue-specific disorders (ribosomopathies) that are often associated with an increased risk of cancer. Ribosomes are the essential macromolecular machines that read the genetic code in all cells in all kingdoms of life. Following pre-assembly in the nucleus, precursors of the large 60S and small 40S ribosomal subunits are exported to the cytoplasm where the final steps in maturation are completed. Here, I review the recent insights into the conserved mechanisms of ribosome assembly that have come from functional characterisation of the genes mutated in human ribosomopathies. In particular, recent advances in cryo-electron microscopy, coupled with genetic, biochemical and prior structural data, have revealed that the SBDS protein that is deficient in the inherited leukaemia predisposition disorder Shwachman-Diamond syndrome couples the final step in cytoplasmic 60S ribosomal subunit maturation to a quality control assessment of the structural and functional integrity of the nascent particle. Thus, study of this fascinating disorder is providing remarkable insights into how the large ribosomal subunit is functionally activated in the cytoplasm to enter the actively translating pool of ribosomes.
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MESH Headings
- Bone Marrow Diseases/metabolism
- Bone Marrow Diseases/pathology
- Cryoelectron Microscopy
- Exocrine Pancreatic Insufficiency/metabolism
- Exocrine Pancreatic Insufficiency/pathology
- Humans
- Lipomatosis/metabolism
- Lipomatosis/pathology
- Mutation
- Proteins/genetics
- Proteins/metabolism
- Ribosome Subunits, Large, Eukaryotic/genetics
- Ribosome Subunits, Large, Eukaryotic/metabolism
- Ribosome Subunits, Large, Eukaryotic/ultrastructure
- Ribosome Subunits, Small, Eukaryotic/genetics
- Ribosome Subunits, Small, Eukaryotic/metabolism
- Ribosome Subunits, Small, Eukaryotic/ultrastructure
- Shwachman-Diamond Syndrome
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Affiliation(s)
- Alan J Warren
- Cambridge Institute for Medical Research, Cambridge, UK; The Department of Haematology, University of Cambridge, Cambridge, UK; Wellcome Trust-Medical Research Council Stem Cell Institute, University of Cambridge, Cambridge, UK.
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29
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Chatterjee K, Majumder S, Wan Y, Shah V, Wu J, Huang HY, Hopper AK. Sharing the load: Mex67-Mtr2 cofunctions with Los1 in primary tRNA nuclear export. Genes Dev 2017; 31:2186-2198. [PMID: 29212662 PMCID: PMC5749166 DOI: 10.1101/gad.305904.117] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 11/06/2017] [Indexed: 11/24/2022]
Abstract
Here, Chatterjee et al. describe a novel tRNA nuclear export pathway that functions in parallel to the tRNA nuclear exporter Los1. They provide molecular, genetic, cytological, and biochemical evidence that the Mex67–Mtr2 (TAP–p15) heterodimer, best characterized for its essential role in mRNA nuclear export, cofunctions with Los1 in tRNA nuclear export. Eukaryotic transfer RNAs (tRNAs) are exported from the nucleus, their site of synthesis, to the cytoplasm, their site of function for protein synthesis. The evolutionarily conserved β-importin family member Los1 (Exportin-t) has been the only exporter known to execute nuclear export of newly transcribed intron-containing pre-tRNAs. Interestingly, LOS1 is unessential in all tested organisms. As tRNA nuclear export is essential, we previously interrogated the budding yeast proteome to identify candidates that function in tRNA nuclear export. Here, we provide molecular, genetic, cytological, and biochemical evidence that the Mex67–Mtr2 (TAP–p15) heterodimer, best characterized for its essential role in mRNA nuclear export, cofunctions with Los1 in tRNA nuclear export. Inactivation of Mex67 or Mtr2 leads to rapid accumulation of end-matured unspliced tRNAs in the nucleus. Remarkably, merely fivefold overexpression of Mex67–Mtr2 can substitute for Los1 in los1Δ cells. Moreover, in vivo coimmunoprecipitation assays with tagged Mex67 document that the Mex67 binds tRNAs. Our data also show that tRNA exporters surprisingly exhibit differential tRNA substrate preferences. The existence of multiple tRNA exporters, each with different tRNA preferences, may indicate that the proteome can be regulated by tRNA nuclear export. Thus, our data show that Mex67–Mtr2 functions in primary nuclear export for a subset of yeast tRNAs.
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Affiliation(s)
- Kunal Chatterjee
- The Ohio State University Comprehensive Cancer Research Center, The Ohio State University, Columbus, Ohio 43210, USA.,Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Shubhra Majumder
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Yao Wan
- The Ohio State University Comprehensive Cancer Research Center, The Ohio State University, Columbus, Ohio 43210, USA.,Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Vijay Shah
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Jingyan Wu
- The Ohio State University Comprehensive Cancer Research Center, The Ohio State University, Columbus, Ohio 43210, USA.,Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Hsiao-Yun Huang
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Anita K Hopper
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
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30
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Zander G, Krebber H. Quick or quality? How mRNA escapes nuclear quality control during stress. RNA Biol 2017; 14:1642-1648. [PMID: 28708448 PMCID: PMC5731798 DOI: 10.1080/15476286.2017.1345835] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 06/19/2017] [Accepted: 06/20/2017] [Indexed: 10/19/2022] Open
Abstract
Understanding the mechanisms for mRNA production under normal conditions and in response to cytotoxic stresses has been subject of numerous studies for several decades. The shutdown of canonical mRNA transcription, export and translation is required to have enough free resources for the immediate production of heat shock proteins that act as chaperones to sustain cellular processes. In recent work we uncovered a simple mechanism, in which the export block of regular mRNAs and a fast export of heat shock mRNAs is achieved by deactivation of the nuclear mRNA quality control mediated by the guard proteins. In this point of view we combine long known data with recently gathered information that support this novel model, in which cells omit quality control of stress responsive transcripts to ensure survival.
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Affiliation(s)
- Gesa Zander
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Göttingen, Germany
| | - Heike Krebber
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Göttingen, Germany
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31
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Eukaryotic ribosome assembly, transport and quality control. Nat Struct Mol Biol 2017; 24:689-699. [PMID: 28880863 DOI: 10.1038/nsmb.3454] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 07/27/2017] [Indexed: 12/18/2022]
Abstract
Eukaryotic ribosome synthesis is a complex, energy-consuming process that takes place across the nucleolus, nucleoplasm and cytoplasm and requires more than 200 conserved assembly factors. Here, we discuss mechanisms by which the ribosome assembly and nucleocytoplasmic transport machineries collaborate to produce functional ribosomes. We also highlight recent cryo-EM studies that provided unprecedented snapshots of ribosomes during assembly and quality control.
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32
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Patchett S, Musalgaonkar S, Malyutin AG, Johnson AW. The T-cell leukemia related rpl10-R98S mutant traps the 60S export adapter Nmd3 in the ribosomal P site in yeast. PLoS Genet 2017; 13:e1006894. [PMID: 28715419 PMCID: PMC5536393 DOI: 10.1371/journal.pgen.1006894] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 07/31/2017] [Accepted: 06/23/2017] [Indexed: 12/12/2022] Open
Abstract
Mutations in the ribosomal protein Rpl10 (uL16) can be drivers of T-cell acute lymphoblastic leukemia (T-ALL). We previously showed that these T-ALL mutations disrupt late cytoplasmic maturation of the 60S ribosomal subunit, blocking the release of the trans-acting factors Nmd3 and Tif6 in S. cerevisiae. Consequently, these mutant ribosomes do not efficiently pass the cytoplasmic quality control checkpoint and are blocked from engaging in translation. Here, we characterize suppressing mutations of the T-ALL-related rpl10-R98S mutant that bypass this block and show that the molecular defect of rpl10-R98S is a failure to release Nmd3 from the P site. Suppressing mutations were identified in Nmd3 and Tif6 that disrupted interactions between Nmd3 and the ribosome, or between Nmd3 and Tif6. Using an in vitro system with purified components, we found that Nmd3 inhibited Sdo1-stimulated Efl1 activity on mutant rpl10-R98S but not wild-type 60S subunits. Importantly, this inhibition was overcome in vitro by mutations in Nmd3 that suppressed rpl10-R98S in vivo. These results strongly support a model that Nmd3 must be dislodged from the P site to allow Sdo1 activation of Efl1, and define a failure in the removal of Nmd3 as the molecular defect of the T-ALL-associated rpl10-R98S mutation. The ribosome is a large and structurally complex macromolecular machine, responsible for synthesizing proteins in all living cells, across all domains of life. The correct assembly of ribosomes is important for their ability to faithfully decode messenger RNAs and synthesize proteins. The insertion of the ribosomal protein Rpl10 into the ribosome completes the catalytic center of the large subunit and is necessary for the removal of the assembly factors Nmd3 and Tif6, which allows the subunit to participate in translation. The insertion of Rpl10 is monitored by proteins that mimic translation factors during a quality control check for ribosome function. Ribosomes containing mutations in Rpl10 associated with pediatric T-cell leukemia fail in this quality control check and prevent the removal of Tif6 and Nmd3. However, it was not known how these mutations in Rpl10 block the quality control check. We recently presented the structure of Nmd3 and Tif6 on the large ribosomal subunit from yeast. In this work, we take advantage of our recent structural work and use a combination of genetic and biochemical techniques to delineate the molecular defect in the ribosome when Rpl10 is mutated.
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Affiliation(s)
- Stephanie Patchett
- Depatment of Molecular Biosciences, the University of Texas at Austin, Austin, Texas, United States of America
| | - Sharmishtha Musalgaonkar
- Depatment of Molecular Biosciences, the University of Texas at Austin, Austin, Texas, United States of America
| | - Andrey G Malyutin
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, United States of America
| | - Arlen W Johnson
- Depatment of Molecular Biosciences, the University of Texas at Austin, Austin, Texas, United States of America
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33
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Espinar-Marchena FJ, Babiano R, Cruz J. Placeholder factors in ribosome biogenesis: please, pave my way. MICROBIAL CELL 2017; 4:144-168. [PMID: 28685141 PMCID: PMC5425277 DOI: 10.15698/mic2017.05.572] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The synthesis of cytoplasmic eukaryotic ribosomes is an extraordinarily energy-demanding cellular activity that occurs progressively from the nucleolus to the cytoplasm. In the nucleolus, precursor rRNAs associate with a myriad of trans-acting factors and some ribosomal proteins to form pre-ribosomal particles. These factors include snoRNPs, nucleases, ATPases, GTPases, RNA helicases, and a vast list of proteins with no predicted enzymatic activity. Their coordinate activity orchestrates in a spatiotemporal manner the modification and processing of precursor rRNAs, the rearrangement reactions required for the formation of productive RNA folding intermediates, the ordered assembly of the ribosomal proteins, and the export of pre-ribosomal particles to the cytoplasm; thus, providing speed, directionality and accuracy to the overall process of formation of translation-competent ribosomes. Here, we review a particular class of trans-acting factors known as "placeholders". Placeholder factors temporarily bind selected ribosomal sites until these have achieved a structural context that is appropriate for exchanging the placeholder with another site-specific binding factor. By this strategy, placeholders sterically prevent premature recruitment of subsequently binding factors, premature formation of structures, avoid possible folding traps, and act as molecular clocks that supervise the correct progression of pre-ribosomal particles into functional ribosomal subunits. We summarize the current understanding of those factors that delay the assembly of distinct ribosomal proteins or subsequently bind key sites in pre-ribosomal particles. We also discuss recurrent examples of RNA-protein and protein-protein mimicry between rRNAs and/or factors, which have clear functional implications for the ribosome biogenesis pathway.
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Affiliation(s)
- Francisco J Espinar-Marchena
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, E-41013, Seville, Spain
| | - Reyes Babiano
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, E-41013, Seville, Spain.,Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, E-41013, Seville, Spain
| | - Jesús Cruz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, E-41013, Seville, Spain
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34
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Malyutin AG, Musalgaonkar S, Patchett S, Frank J, Johnson AW. Nmd3 is a structural mimic of eIF5A, and activates the cpGTPase Lsg1 during 60S ribosome biogenesis. EMBO J 2017; 36:854-868. [PMID: 28179369 PMCID: PMC5376978 DOI: 10.15252/embj.201696012] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 01/17/2017] [Accepted: 01/18/2017] [Indexed: 12/22/2022] Open
Abstract
During ribosome biogenesis in eukaryotes, nascent subunits are exported to the cytoplasm in a functionally inactive state. 60S subunits are activated through a series of cytoplasmic maturation events. The last known events in the cytoplasm are the release of Tif6 by Efl1 and Sdo1 and the release of the export adapter, Nmd3, by the GTPase Lsg1. Here, we have used cryo-electron microscopy to determine the structure of the 60S subunit bound by Nmd3, Lsg1, and Tif6. We find that a central domain of Nmd3 mimics the translation elongation factor eIF5A, inserting into the E site of the ribosome and pulling the L1 stalk into a closed position. Additional domains occupy the P site and extend toward the sarcin-ricin loop to interact with Tif6. Nmd3 and Lsg1 together embrace helix 69 of the B2a intersubunit bridge, inducing base flipping that we suggest may activate the GTPase activity of Lsg1.
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Affiliation(s)
- Andrey G Malyutin
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | | | - Stephanie Patchett
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Joachim Frank
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
- Department of Biological Sciences, Columbia University, New York, NY, USA
- Howard Hughes Medical Institute, Columbia University, New York, NY, USA
| | - Arlen W Johnson
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
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35
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Structural snapshot of cytoplasmic pre-60S ribosomal particles bound by Nmd3, Lsg1, Tif6 and Reh1. Nat Struct Mol Biol 2017; 24:214-220. [PMID: 28112732 DOI: 10.1038/nsmb.3364] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 12/19/2016] [Indexed: 01/01/2023]
Abstract
A key step in ribosome biogenesis is the nuclear export of pre-ribosomal particles. Nmd3, a highly conserved protein in eukaryotes, is a specific adaptor required for the export of pre-60S particles. Here we used cryo-electron microscopy (cryo-EM) to characterize Saccharomyces cerevisiae pre-60S particles purified with epitope-tagged Nmd3. Our structural analysis indicates that these particles belong to a specific late stage of cytoplasmic pre-60S maturation in which ribosomal proteins uL16, uL10, uL11, eL40 and eL41 are deficient, but ribosome assembly factors Nmd3, Lsg1, Tif6 and Reh1 are present. Nmd3 and Lsg1 are located near the peptidyl-transferase center (PTC). In particular, Nmd3 recognizes the PTC in its near-mature conformation. In contrast, Reh1 is anchored to the exit of the polypeptide tunnel, with its C terminus inserted into the tunnel. These findings pinpoint a structural checkpoint role for Nmd3 in PTC assembly, and provide information about functional and mechanistic roles of these assembly factors in the maturation of the 60S ribosomal subunit.
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36
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Ting YH, Lu TJ, Johnson AW, Shie JT, Chen BR, Kumar S S, Lo KY. Bcp1 Is the Nuclear Chaperone of Rpl23 in Saccharomyces cerevisiae. J Biol Chem 2016; 292:585-596. [PMID: 27913624 DOI: 10.1074/jbc.m116.747634] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 11/21/2016] [Indexed: 12/18/2022] Open
Abstract
Eukaryotic ribosomes are composed of rRNAs and ribosomal proteins. Ribosomal proteins are translated in the cytoplasm and imported into the nucleus for assembly with the rRNAs. It has been shown that chaperones or karyopherins responsible for import can maintain the stability of ribosomal proteins by neutralizing unfavorable positive charges and thus facilitate their transports. Among 79 ribosomal proteins in yeast, only a few are identified with specific chaperones. Besides the classic role in maintaining protein stability, chaperones have additional roles in transport, chaperoning the assembly site, and dissociation of ribosomal proteins from karyopherins. Bcp1 has been shown to be necessary for the export of Mss4, a phosphatidylinositol 4-phosphate 5-kinase, and required for ribosome biogenesis. However, its specific function in ribosome biogenesis has not been described. Here, we show that Bcp1 dissociates Rpl23 from the karyopherins and associates with Rpl23 afterward. Loss of Bcp1 causes instability of Rpl23 and deficiency of 60S subunits. In summary, Bcp1 is a novel 60S biogenesis factor via chaperoning Rpl23 in the nucleus.
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Affiliation(s)
- Ya-Han Ting
- From the Department of Agricultural Chemistry, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Ting-Jun Lu
- From the Department of Agricultural Chemistry, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Arlen W Johnson
- the Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712, and
| | - Jing-Ting Shie
- From the Department of Agricultural Chemistry, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Bo-Ru Chen
- From the Department of Agricultural Chemistry, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Suresh Kumar S
- From the Department of Agricultural Chemistry, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.,the Department of Medical Microbiology and Parasitology, Universiti Putra Malaysia, 43400 Selangor, Malaysia
| | - Kai-Yin Lo
- From the Department of Agricultural Chemistry, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei 10617, Taiwan,
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37
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Human PDCD2L Is an Export Substrate of CRM1 That Associates with 40S Ribosomal Subunit Precursors. Mol Cell Biol 2016; 36:3019-3032. [PMID: 27697862 DOI: 10.1128/mcb.00303-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 09/15/2016] [Indexed: 01/05/2023] Open
Abstract
Protein arginine methyltransferase 3 (PRMT3) forms a stable complex with 40S ribosomal protein S2 (RPS2) and contributes to ribosome biogenesis. However, the molecular mechanism by which PRMT3 influences ribosome biogenesis and/or function still remains unclear. Using quantitative proteomics, we identified human programmed cell death 2-like (PDCD2L) as a novel PRMT3-associated protein. Our data suggest that RPS2 promotes the formation of a conserved extraribosomal complex with PRMT3 and PDCD2L. We also show that PDCD2L associates with 40S subunit precursors that contain a 3'-extended form of the 18S rRNA (18S-E pre-rRNA) and several pre-40S maturation factors. PDCD2L shuttles between the nucleus and the cytoplasm in a CRM1-dependent manner using a leucine-rich nuclear export signal that is sufficient to direct the export of a reporter protein. Although PDCD2L is not required for the biogenesis and export of 40S ribosomal subunits, we found that PDCD2L-null cells accumulate free 60S ribosomal subunits, which is indicative of a deficiency in 40S subunit availability. Our data also indicate that PDCD2L and its paralog, PDCD2, function redundantly in 40S ribosomal subunit production. Our findings uncover the existence of an extraribosomal complex consisting of PDCD2L, RPS2, and PRMT3 and support a role for PDCD2L in the late maturation of 40S ribosomal subunits.
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38
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Greber BJ. Mechanistic insight into eukaryotic 60S ribosomal subunit biogenesis by cryo-electron microscopy. RNA (NEW YORK, N.Y.) 2016; 22:1643-1662. [PMID: 27875256 PMCID: PMC5066618 DOI: 10.1261/rna.057927.116] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Eukaryotic ribosomes, the protein-producing factories of the cell, are composed of four ribosomal RNA molecules and roughly 80 proteins. Their biogenesis is a complex process that involves more than 200 biogenesis factors that facilitate the production, modification, and assembly of ribosomal components and the structural transitions along the maturation pathways of the pre-ribosomal particles. Here, I review recent structural and mechanistic insights into the biogenesis of the large ribosomal subunit that were furthered by cryo-electron microscopy of natively purified pre-60S particles and in vitro reconstituted ribosome assembly factor complexes. Combined with biochemical, genetic, and previous structural data, these structures have provided detailed insights into the assembly and maturation of the central protuberance of the 60S subunit, the network of biogenesis factors near the ribosomal tunnel exit, and the functional activation of the large ribosomal subunit during cytoplasmic maturation.
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Affiliation(s)
- Basil J Greber
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California 94720-3220, USA
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39
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Sarkar A, Pech M, Thoms M, Beckmann R, Hurt E. Ribosome-stalk biogenesis is coupled with recruitment of nuclear-export factor to the nascent 60S subunit. Nat Struct Mol Biol 2016; 23:1074-1082. [PMID: 27775710 DOI: 10.1038/nsmb.3312] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Accepted: 09/26/2016] [Indexed: 12/16/2022]
Abstract
Nuclear export of preribosomal subunits is a key step during eukaryotic ribosome formation. To efficiently pass through the FG-repeat meshwork of the nuclear pore complex, the large pre-60S subunit requires several export factors. Here we describe the mechanism of recruitment of the Saccharomyces cerevisiae RNA-export receptor Mex67-Mtr2 to the pre-60S subunit at the proper time. Mex67-Mtr2 binds at the premature ribosomal-stalk region, which later during translation serves as a binding platform for translational GTPases on the mature ribosome. The assembly factor Mrt4, a structural homolog of cytoplasmic-stalk protein P0, masks this site, thus preventing untimely recruitment of Mex67-Mtr2 to nuclear pre-60S particles. Subsequently, Yvh1 triggers Mrt4 release in the nucleus, thereby creating a narrow time window for Mex67-Mtr2 association at this site and facilitating nuclear export of the large subunit. Thus, a spatiotemporal mark on the ribosomal stalk controls the recruitment of an RNA-export receptor to the nascent 60S subunit.
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Affiliation(s)
- Anshuk Sarkar
- Biochemistry Centre, University of Heidelberg, Heidelberg, Germany
| | - Markus Pech
- Gene Center, University of Munich, Munich, Germany
| | - Matthias Thoms
- Biochemistry Centre, University of Heidelberg, Heidelberg, Germany
| | | | - Ed Hurt
- Biochemistry Centre, University of Heidelberg, Heidelberg, Germany
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40
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Domanska A, Kaminska J. Role of Rsp5 ubiquitin ligase in biogenesis of rRNA, mRNA and tRNA in yeast. RNA Biol 2016; 12:1265-74. [PMID: 26403176 DOI: 10.1080/15476286.2015.1094604] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Rsp5 ubiquitin ligase is required for ubiquitination of a wide variety of proteins involved in essential processes. Rsp5 was shown to be involved in regulation of lipid biosynthesis, intracellular trafficking of proteins, response to various stresses, and many other processes. In this article, we provide a comprehensive review of the nuclear and cytoplasmic functions of Rsp5 with a focus on biogenesis of different RNAs. We also briefly describe the participation of Rsp5 in the regulation of the RNA polymerase II complex, and its potential role in the regulation of other RNA polymerases. Moreover, we emphasize the function of Rsp5 in the coordination of the different steps of rRNA, mRNA and tRNA metabolism in the context of protein biosynthesis. Finally, we highlight the involvement of Rsp5 in controlling diverse cellular mechanisms at multiple levels and in adaptation of the cell to changing growth conditions.
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Affiliation(s)
- Anna Domanska
- a Institute of Biochemistry and Biophysics, Polish Academy of Sciences ; Warsaw , Poland
| | - Joanna Kaminska
- a Institute of Biochemistry and Biophysics, Polish Academy of Sciences ; Warsaw , Poland
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41
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Fernández-Pevida A, Martín-Villanueva S, Murat G, Lacombe T, Kressler D, de la Cruz J. The eukaryote-specific N-terminal extension of ribosomal protein S31 contributes to the assembly and function of 40S ribosomal subunits. Nucleic Acids Res 2016; 44:7777-91. [PMID: 27422873 PMCID: PMC5027506 DOI: 10.1093/nar/gkw641] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 07/07/2016] [Indexed: 11/12/2022] Open
Abstract
The archaea-/eukaryote-specific 40S-ribosomal-subunit protein S31 is expressed as an ubiquitin fusion protein in eukaryotes and consists of a conserved body and a eukaryote-specific N-terminal extension. In yeast, S31 is a practically essential protein, which is required for cytoplasmic 20S pre-rRNA maturation. Here, we have studied the role of the N-terminal extension of the yeast S31 protein. We show that deletion of this extension partially impairs cell growth and 40S subunit biogenesis and confers hypersensitivity to aminoglycoside antibiotics. Moreover, the extension harbours a nuclear localization signal that promotes active nuclear import of S31, which associates with pre-ribosomal particles in the nucleus. In the absence of the extension, truncated S31 inefficiently assembles into pre-40S particles and two subpopulations of mature small subunits, one lacking and another one containing truncated S31, can be identified. Plasmid-driven overexpression of truncated S31 partially suppresses the growth and ribosome biogenesis defects but, conversely, slightly enhances the hypersensitivity to aminoglycosides. Altogether, these results indicate that the N-terminal extension facilitates the assembly of S31 into pre-40S particles and contributes to the optimal translational activity of mature 40S subunits but has only a minor role in cytoplasmic cleavage of 20S pre-rRNA at site D.
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Affiliation(s)
- Antonio Fernández-Pevida
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Avda. Manuel Siurot, s/n; E-41013 Seville, Spain Departamento de Genética, Universidad de Sevilla, Seville, Spain
| | - Sara Martín-Villanueva
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Avda. Manuel Siurot, s/n; E-41013 Seville, Spain Departamento de Genética, Universidad de Sevilla, Seville, Spain
| | - Guillaume Murat
- Unit of Biochemistry, Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland
| | - Thierry Lacombe
- Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland
| | - Dieter Kressler
- Unit of Biochemistry, Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland
| | - Jesús de la Cruz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Avda. Manuel Siurot, s/n; E-41013 Seville, Spain Departamento de Genética, Universidad de Sevilla, Seville, Spain
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42
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Abstract
Growing evidence demonstrates that metabolism and chromatin dynamics are not separate processes but that they functionally intersect in many ways. For example, the lysine biosynthetic enzyme homocitrate synthase was recently shown to have unexpected functions in DNA damage repair, raising the question of whether other amino acid metabolic enzymes participate in chromatin regulation. Using an in silico screen combined with reporter assays, we discovered that a diverse range of metabolic enzymes function in heterochromatin regulation. Extended analysis of the glutamate dehydrogenase 1 (Gdh1) revealed that it regulates silent information regulator complex recruitment to telomeres and ribosomal DNA. Enhanced N-terminal histone H3 proteolysis is observed in GDH1 mutants, consistent with telomeric silencing defects. A conserved catalytic Asp residue is required for Gdh1's functions in telomeric silencing and H3 clipping. Genetic modulation of α-ketoglutarate levels demonstrates a key regulatory role for this metabolite in telomeric silencing. The metabolic activity of glutamate dehydrogenase thus has important and previously unsuspected roles in regulating chromatin-related processes.
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43
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Neumann B, Wu H, Hackmann A, Krebber H. Nuclear Export of Pre-Ribosomal Subunits Requires Dbp5, but Not as an RNA-Helicase as for mRNA Export. PLoS One 2016; 11:e0149571. [PMID: 26872259 PMCID: PMC4752221 DOI: 10.1371/journal.pone.0149571] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 02/01/2016] [Indexed: 11/28/2022] Open
Abstract
The DEAD-box RNA-helicase Dbp5/Rat8 is known for its function in nuclear mRNA export, where it displaces the export receptor Mex67 from the mRNA at the cytoplasmic side of the nuclear pore complex (NPC). Here we show that Dbp5 is also required for the nuclear export of both pre-ribosomal subunits. Yeast temperature-sensitive dbp5 mutants accumulate both ribosomal particles in their nuclei. Furthermore, Dbp5 genetically and physically interacts with known ribosomal transport factors such as Nmd3. Similar to mRNA export we show that also for ribosomal transport Dbp5 is required at the cytoplasmic side of the NPC. However, unlike its role in mRNA export, Dbp5 does not seem to undergo its ATPase cycle for this function, as ATPase-deficient dbp5 mutants that selectively inhibit mRNA export do not affect ribosomal transport. Furthermore, mutants of GLE1, the ATPase stimulating factor of Dbp5, show no major ribosomal export defects. Consequently, while Dbp5 uses its ATPase cycle to displace the export receptor Mex67 from the translocated mRNAs, Mex67 remains bound to ribosomal subunits upon transit to the cytoplasm, where it is detectable on translating ribosomes. Therefore, we propose a model, in which Dbp5 supports ribosomal transport by capturing ribosomal subunits upon their cytoplasmic appearance at the NPC, possibly by binding export factors such as Mex67. Thus, our findings reveal that although different ribonucleoparticles, mRNAs and pre-ribosomal subunits, use shared export factors, they utilize different transport mechanisms.
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Affiliation(s)
- Bettina Neumann
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Germany
| | - Haijia Wu
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Germany
| | - Alexandra Hackmann
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Germany
| | - Heike Krebber
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Germany
- * E-mail:
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44
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Kırlı K, Karaca S, Dehne HJ, Samwer M, Pan KT, Lenz C, Urlaub H, Görlich D. A deep proteomics perspective on CRM1-mediated nuclear export and nucleocytoplasmic partitioning. eLife 2015; 4:e11466. [PMID: 26673895 PMCID: PMC4764573 DOI: 10.7554/elife.11466] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 12/13/2015] [Indexed: 12/23/2022] Open
Abstract
CRM1 is a highly conserved, RanGTPase-driven exportin that carries proteins and RNPs from the nucleus to the cytoplasm. We now explored the cargo-spectrum of CRM1 in depth and identified surprisingly large numbers, namely >700 export substrates from the yeast S. cerevisiae, ≈1000 from Xenopus oocytes and >1050 from human cells. In addition, we quantified the partitioning of ≈5000 unique proteins between nucleus and cytoplasm of Xenopus oocytes. The data suggest new CRM1 functions in spatial control of vesicle coat-assembly, centrosomes, autophagy, peroxisome biogenesis, cytoskeleton, ribosome maturation, translation, mRNA degradation, and more generally in precluding a potentially detrimental action of cytoplasmic pathways within the nuclear interior. There are also numerous new instances where CRM1 appears to act in regulatory circuits. Altogether, our dataset allows unprecedented insights into the nucleocytoplasmic organisation of eukaryotic cells, into the contributions of an exceedingly promiscuous exportin and it provides a new basis for NES prediction.
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Affiliation(s)
- Koray Kırlı
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Samir Karaca
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Heinz Jürgen Dehne
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Matthias Samwer
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Kuan Ting Pan
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Christof Lenz
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- Bioanalytics, Institute for Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- Bioanalytics, Institute for Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Dirk Görlich
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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45
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A nuclear fraction of turnip crinkle virus capsid protein is important for elicitation of the host resistance response. Virus Res 2015; 210:264-70. [PMID: 26299399 DOI: 10.1016/j.virusres.2015.08.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 08/11/2015] [Accepted: 08/15/2015] [Indexed: 11/21/2022]
Abstract
The N-terminal 25 amino acids (AAs) of turnip crinkle virus (TCV) capsid protein (CP) are recognized by the resistance protein HRT to trigger a hypersensitive response (HR) and systemic resistance to TCV infection. This same region of TCV CP also contains a motif that interacts with the transcription factor TIP, as well as a nuclear localization signal (NLS). However, it is not yet known whether nuclear localization of TCV CP is needed for the induction of HRT-mediated HR and resistance. Here we present new evidence suggesting a tight correlation between nuclear inclusions formed by CP and the manifestation of HR. We show that a fraction of TCV CP localized to cell nuclei to form discrete inclusion-like structures, and a mutated CP (R6A) known to abolish HR failed to form nuclear inclusions. Notably, TIP-CP interaction augments the inclusion-forming activity of CP by tethering inclusions to the nuclear membrane. This TIP-mediated augmentation is also critical for HR resistance, as another CP mutant (R8A) known to elicit a less restrictive HR, though still self-associated into nuclear inclusions, failed to direct inclusions to the nuclear membrane due to its inability to interact with TIP. Finally, exclusion of CP from cell nuclei abolished induction of HR. Together, these results uncovered a strong correlation between nuclear localization and nuclear inclusion formation by TCV CP and induction of HR, and suggest that CP nuclear inclusions could be the key trigger of the HRT-dependent, yet TIP-reinforced, resistance to TCV.
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46
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Barrio-Garcia C, Thoms M, Flemming D, Kater L, Berninghausen O, Baßler J, Beckmann R, Hurt E. Architecture of the Rix1-Rea1 checkpoint machinery during pre-60S-ribosome remodeling. Nat Struct Mol Biol 2015; 23:37-44. [PMID: 26619264 DOI: 10.1038/nsmb.3132] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 10/30/2015] [Indexed: 01/01/2023]
Abstract
Ribosome synthesis is catalyzed by ∼200 assembly factors, which facilitate efficient production of mature ribosomes. Here, we determined the cryo-EM structure of a Saccharomyces cerevisiae nucleoplasmic pre-60S particle containing the dynein-related 550-kDa Rea1 AAA(+) ATPase and the Rix1 subcomplex. This particle differs from its preceding state, the early Arx1 particle, by two massive structural rearrangements: an ∼180° rotation of the 5S ribonucleoprotein complex and the central protuberance (CP) rRNA helices, and the removal of the 'foot' structure from the 3' end of the 5.8S rRNA. Progression from the Arx1 to the Rix1 particle was blocked by mutational perturbation of the Rix1-Rea1 interaction but not by a dominant-lethal Rea1 AAA(+) ATPase-ring mutant. After remodeling, the Rix1 subcomplex and Rea1 become suitably positioned to sense correct structural maturation of the CP, which allows unidirectional progression toward mature ribosomes.
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Affiliation(s)
| | - Matthias Thoms
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Dirk Flemming
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Lukas Kater
- Gene Center, University of Munich, Munich, Germany
| | | | - Jochen Baßler
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | | | - Ed Hurt
- Heidelberg University Biochemistry Center, Heidelberg, Germany
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47
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Zhao H, Lü S, Li R, Chen T, Zhang H, Cui P, Ding F, Liu P, Wang G, Xia Y, Running MP, Xiong L. The Arabidopsis gene DIG6 encodes a large 60S subunit nuclear export GTPase 1 that is involved in ribosome biogenesis and affects multiple auxin-regulated development processes. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:6863-75. [PMID: 26272902 PMCID: PMC4623693 DOI: 10.1093/jxb/erv391] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The circularly permuted GTPase large subunit GTPase 1 (LSG1) is involved in the maturation step of the 60S ribosome and is essential for cell viability in yeast. Here, an Arabidopsis mutant dig6 (drought inhibited growth of lateral roots) was isolated. The mutant exhibited multiple auxin-related phenotypes, which included reduced lateral root number, altered leaf veins, and shorter roots. Genetic mapping combined with next-generation DNA sequencing identified that the mutation occurred in AtLSG1-2. This gene was highly expressed in regions of auxin accumulation. Ribosome profiling revealed that a loss of function of AtLSG1-2 led to decreased levels of monosomes, further demonstrating its role in ribosome biogenesis. Quantitative proteomics showed that the expression of certain proteins involved in ribosome biogenesis was differentially regulated, indicating that ribosome biogenesis processes were impaired in the mutant. Further investigations showed that an AtLSG1-2 deficiency caused the alteration of auxin distribution, response, and transport in plants. It is concluded that AtLSG1-2 is integral to ribosome biogenesis, consequently affecting auxin homeostasis and plant development.
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Affiliation(s)
- Huayan Zhao
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Shiyou Lü
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China
| | - Ruixi Li
- Institute for Integrative Genome Biology, Center for Plant Cell Biology & Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Tao Chen
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Huoming Zhang
- Bioscience Core Lab, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Peng Cui
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Feng Ding
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Pei Liu
- Department of Biology, Hong Kong Baptist University, Hong Kong, P. R. China
| | - Guangchao Wang
- Bioscience Core Lab, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Yiji Xia
- Department of Biology, Hong Kong Baptist University, Hong Kong, P. R. China
| | - Mark P Running
- Department of Biology, University of Louisville, Louisville, KY 40292, USA
| | - Liming Xiong
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
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48
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Sloan KE, Gleizes PE, Bohnsack MT. Nucleocytoplasmic Transport of RNAs and RNA-Protein Complexes. J Mol Biol 2015; 428:2040-59. [PMID: 26434509 DOI: 10.1016/j.jmb.2015.09.023] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 09/26/2015] [Accepted: 09/28/2015] [Indexed: 12/15/2022]
Abstract
RNAs and ribonucleoprotein complexes (RNPs) play key roles in mediating and regulating gene expression. In eukaryotes, most RNAs are transcribed, processed and assembled with proteins in the nucleus and then either function in the cytoplasm or also undergo a cytoplasmic phase in their biogenesis. This compartmentalization ensures that sequential steps in gene expression and RNP production are performed in the correct order and it allows important quality control mechanisms that prevent the involvement of aberrant RNAs/RNPs in these cellular pathways. The selective exchange of RNAs/RNPs between the nucleus and cytoplasm is enabled by nuclear pore complexes, which function as gateways between these compartments. RNA/RNP transport is facilitated by a range of nuclear transport receptors and adaptors, which are specifically recruited to their cargos and mediate interactions with nucleoporins to allow directional translocation through nuclear pore complexes. While some transport factors are only responsible for the export/import of a certain class of RNA/RNP, others are multifunctional and, in the case of large RNPs, several export factors appear to work together to bring about export. Recent structural studies have revealed aspects of the mechanisms employed by transport receptors to enable specific cargo recognition, and genome-wide approaches have provided the first insights into the diverse composition of pre-mRNPs during export. Furthermore, the regulation of RNA/RNP export is emerging as an important means to modulate gene expression under stress conditions and in disease.
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Affiliation(s)
- Katherine E Sloan
- Institute for Molecular Biology, Goettingen University Medical Department, 37073 Goettingen, Germany
| | - Pierre-Emmanuel Gleizes
- Laboratoire de Biologie Moléculaire Eucaryote, UMR 5099, Université de Toulouse-Paul Sabatier, CNRS, Toulouse, France
| | - Markus T Bohnsack
- Institute for Molecular Biology, Goettingen University Medical Department, 37073 Goettingen, Germany; Goettingen Centre for Molecular Biosciences, Georg-August-University, 37075 Goettingen, Germany.
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49
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Zanni G, Kalscheuer VM, Friedrich A, Barresi S, Alfieri P, Di Capua M, Haas SA, Piccini G, Karl T, Klauck SM, Bellacchio E, Emma F, Cappa M, Bertini E, Breitenbach-Koller L. A Novel Mutation in RPL10 (Ribosomal Protein L10) Causes X-Linked Intellectual Disability, Cerebellar Hypoplasia, and Spondylo-Epiphyseal Dysplasia. Hum Mutat 2015; 36:1155-8. [PMID: 26290468 DOI: 10.1002/humu.22860] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 08/12/2015] [Indexed: 11/12/2022]
Abstract
RPL10 encodes ribosomal protein L10 (uL16), a highly conserved multifunctional component of the large ribosomal subunit, involved in ribosome biogenesis and function. Using X-exome resequencing, we identified a novel missense mutation (c.191C>T; p.(A64V)) in the N-terminal domain of the protein, in a family with two affected cousins presenting with X-linked intellectual disability, cerebellar hypoplasia, and spondylo-epiphyseal dysplasia (SED). We assessed the impact of the mutation on the translational capacity of the cell using yeast as model system. The mutation generates a functional ribosomal protein, able to complement the translational defects of a conditional lethal mutation of yeast rpl10. However, unlike previously reported mutations, this novel RPL10 missense mutation results in an increase in the actively translating ribosome population. Our results expand the mutational and clinical spectrum of RPL10 identifying a new genetic cause of SED and highlight the emerging role of ribosomal proteins in the pathogenesis of neurodevelopmental disorders.
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Affiliation(s)
- Ginevra Zanni
- Unit of Molecular Medicine for Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children's Hospital, IRRCS, Rome, Italy
| | - Vera M Kalscheuer
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Andreas Friedrich
- Department of Cell Biology, University of Salzburg, Salzburg, Austria
| | - Sabina Barresi
- Unit of Molecular Medicine for Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children's Hospital, IRRCS, Rome, Italy
| | - Paolo Alfieri
- Unit of Child Neuropsychiatry, Department of Neurosciences, Bambino Gesù Children's Hospital, IRRCS, Rome, Italy
| | - Matteo Di Capua
- Unit of Neurology, Department of Neurosciences, Bambino Gesù Children's Hospital, IRRCS, Rome, Italy
| | - Stefan A Haas
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Giorgia Piccini
- Unit of Child Neuropsychiatry, Department of Neurosciences, Bambino Gesù Children's Hospital, IRRCS, Rome, Italy
| | - Thomas Karl
- Department of Cell Biology, University of Salzburg, Salzburg, Austria
| | - Sabine M Klauck
- Division of Molecular Genome Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | - Francesco Emma
- Unit of Nephrology, Department of Pediatrics, Bambino Gesù Children's Hospital, IRRCS, Rome, Italy
| | - Marco Cappa
- Unit of Clinical Endocrinology, Department of Pediatrics, Bambino Gesù Children's Hospital, IRRCS, Rome, Italy
| | - Enrico Bertini
- Unit of Molecular Medicine for Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children's Hospital, IRRCS, Rome, Italy
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50
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Stuwe T, Bley CJ, Thierbach K, Petrovic S, Schilbach S, Mayo DJ, Perriches T, Rundlet EJ, Jeon YE, Collins LN, Huber FM, Lin DH, Paduch M, Koide A, Lu V, Fischer J, Hurt E, Koide S, Kossiakoff AA, Hoelz A. Architecture of the fungal nuclear pore inner ring complex. Science 2015; 350:56-64. [PMID: 26316600 DOI: 10.1126/science.aac9176] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 08/12/2015] [Indexed: 12/20/2022]
Abstract
The nuclear pore complex (NPC) constitutes the sole gateway for bidirectional nucleocytoplasmic transport. We present the reconstitution and interdisciplinary analyses of the ~425-kilodalton inner ring complex (IRC), which forms the central transport channel and diffusion barrier of the NPC, revealing its interaction network and equimolar stoichiometry. The Nsp1•Nup49•Nup57 channel nucleoporin heterotrimer (CNT) attaches to the IRC solely through the adaptor nucleoporin Nic96. The CNT•Nic96 structure reveals that Nic96 functions as an assembly sensor that recognizes the three-dimensional architecture of the CNT, thereby mediating the incorporation of a defined CNT state into the NPC. We propose that the IRC adopts a relatively rigid scaffold that recruits the CNT to primarily form the diffusion barrier of the NPC, rather than enabling channel dilation.
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Affiliation(s)
- Tobias Stuwe
- California Institute of Technology, Division of Chemistry and Chemical Engineering, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Christopher J Bley
- California Institute of Technology, Division of Chemistry and Chemical Engineering, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Karsten Thierbach
- California Institute of Technology, Division of Chemistry and Chemical Engineering, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Stefan Petrovic
- California Institute of Technology, Division of Chemistry and Chemical Engineering, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Sandra Schilbach
- California Institute of Technology, Division of Chemistry and Chemical Engineering, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Daniel J Mayo
- California Institute of Technology, Division of Chemistry and Chemical Engineering, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Thibaud Perriches
- California Institute of Technology, Division of Chemistry and Chemical Engineering, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Emily J Rundlet
- California Institute of Technology, Division of Chemistry and Chemical Engineering, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Young E Jeon
- California Institute of Technology, Division of Chemistry and Chemical Engineering, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Leslie N Collins
- California Institute of Technology, Division of Chemistry and Chemical Engineering, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Ferdinand M Huber
- California Institute of Technology, Division of Chemistry and Chemical Engineering, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Daniel H Lin
- California Institute of Technology, Division of Chemistry and Chemical Engineering, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Marcin Paduch
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Akiko Koide
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Vincent Lu
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Jessica Fischer
- Biochemistry Center of Heidelberg University, 69120 Heidelberg, Germany
| | - Ed Hurt
- Biochemistry Center of Heidelberg University, 69120 Heidelberg, Germany
| | - Shohei Koide
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Anthony A Kossiakoff
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - André Hoelz
- California Institute of Technology, Division of Chemistry and Chemical Engineering, 1200 East California Boulevard, Pasadena, CA 91125, USA.
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