1
|
Busselez J, Koenig G, Dominique C, Klos T, Velayudhan D, Sosnowski P, Marechal N, Crucifix C, Gizardin-Fredon H, Cianferani S, Albert B, Henry Y, Henras AK, Schmidt H. Remodelling of Rea1 linker domain drives the removal of assembly factors from pre-ribosomal particles. Nat Commun 2024; 15:10309. [PMID: 39604383 PMCID: PMC11603028 DOI: 10.1038/s41467-024-54698-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 11/18/2024] [Indexed: 11/29/2024] Open
Abstract
The ribosome maturation factor Rea1 (or Midasin) catalyses the removal of assembly factors from large ribosomal subunit precursors and promotes their export from the nucleus to the cytosol. Rea1 consists of nearly 5000 amino-acid residues and belongs to the AAA+ protein family. It consists of a ring of six AAA+ domains from which the ≈1700 amino-acid residue linker emerges that is subdivided into stem, middle and top domains. A flexible and unstructured D/E rich region connects the linker top to a MIDAS (metal ion dependent adhesion site) domain, which is able to bind the assembly factor substrates. Despite its key importance for ribosome maturation, the mechanism driving assembly factor removal by Rea1 is still poorly understood. Here we demonstrate that the Rea1 linker is essential for assembly factor removal. It rotates and swings towards the AAA+ ring following a complex remodelling scheme involving nucleotide independent as well as nucleotide dependent steps. ATP-hydrolysis is required to engage the linker with the AAA+ ring and ultimately with the AAA+ ring docked MIDAS domain. The interaction between the linker top and the MIDAS domain allows direct force transmission for assembly factor removal.
Collapse
Affiliation(s)
- Johan Busselez
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Integrated Structural Biology Department, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Geraldine Koenig
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Integrated Structural Biology Department, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Carine Dominique
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Torben Klos
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Integrated Structural Biology Department, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Deepika Velayudhan
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Integrated Structural Biology Department, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Piotr Sosnowski
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Integrated Structural Biology Department, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
- BIOMEX, Siemenstrasse 38, 69123, Heidelberg, Germany
| | - Nils Marechal
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Integrated Structural Biology Department, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Corinne Crucifix
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Integrated Structural Biology Department, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Hugo Gizardin-Fredon
- Laboratoire de Spectrométrie de Masse BioOrganique, IPHC UMR 7178, Université de Strasbourg, CNRS, Strasbourg, France
- Infrastructure Nationale de Protéomique ProFI - FR2048, Strasbourg, France
| | - Sarah Cianferani
- Laboratoire de Spectrométrie de Masse BioOrganique, IPHC UMR 7178, Université de Strasbourg, CNRS, Strasbourg, France
- Infrastructure Nationale de Protéomique ProFI - FR2048, Strasbourg, France
| | - Benjamin Albert
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Yves Henry
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Anthony K Henras
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Helgo Schmidt
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Integrated Structural Biology Department, Illkirch, France.
- Centre National de la Recherche Scientifique, Illkirch, France.
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France.
- Université de Strasbourg, Illkirch, France.
| |
Collapse
|
2
|
Martín-Villanueva S, Gutiérrez G, Kressler D, de la Cruz J. Ubiquitin and Ubiquitin-Like Proteins and Domains in Ribosome Production and Function: Chance or Necessity? Int J Mol Sci 2021; 22:ijms22094359. [PMID: 33921964 PMCID: PMC8122580 DOI: 10.3390/ijms22094359] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 12/11/2022] Open
Abstract
Ubiquitin is a small protein that is highly conserved throughout eukaryotes. It operates as a reversible post-translational modifier through a process known as ubiquitination, which involves the addition of one or several ubiquitin moieties to a substrate protein. These modifications mark proteins for proteasome-dependent degradation or alter their localization or activity in a variety of cellular processes. In most eukaryotes, ubiquitin is generated by the proteolytic cleavage of precursor proteins in which it is fused either to itself, constituting a polyubiquitin precursor, or as a single N-terminal moiety to ribosomal proteins, which are practically invariably eL40 and eS31. Herein, we summarize the contribution of the ubiquitin moiety within precursors of ribosomal proteins to ribosome biogenesis and function and discuss the biological relevance of having maintained the explicit fusion to eL40 and eS31 during evolution. There are other ubiquitin-like proteins, which also work as post-translational modifiers, among them the small ubiquitin-like modifier (SUMO). Both ubiquitin and SUMO are able to modify ribosome assembly factors and ribosomal proteins to regulate ribosome biogenesis and function. Strikingly, ubiquitin-like domains are also found within two ribosome assembly factors; hence, the functional role of these proteins will also be highlighted.
Collapse
Affiliation(s)
- Sara Martín-Villanueva
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41009 Seville, Spain;
- Departamento de Genética, Universidad de Sevilla, 41013 Seville, Spain;
| | - Gabriel Gutiérrez
- Departamento de Genética, Universidad de Sevilla, 41013 Seville, Spain;
| | - Dieter Kressler
- Unit of Biochemistry, Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland
- Correspondence: (D.K.); (J.d.l.C.); Tel.: +41-26-300-86-45 (D.K.); +34-955-923-126 (J.d.l.C.)
| | - Jesús de la Cruz
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41009 Seville, Spain;
- Departamento de Genética, Universidad de Sevilla, 41013 Seville, Spain;
- Correspondence: (D.K.); (J.d.l.C.); Tel.: +41-26-300-86-45 (D.K.); +34-955-923-126 (J.d.l.C.)
| |
Collapse
|
3
|
Gallegos KM, Patel JR, Llopis SD, Walker RR, Davidson AM, Zhang W, Zhang K, Tilghman SL. Quantitative Proteomic Profiling Identifies a Potential Novel Chaperone Marker in Resistant Breast Cancer. Front Oncol 2021; 11:540134. [PMID: 33718123 PMCID: PMC7951058 DOI: 10.3389/fonc.2021.540134] [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: 03/03/2020] [Accepted: 01/06/2021] [Indexed: 12/12/2022] Open
Abstract
Development of aromatase inhibitor resistant breast cancer among postmenopausal women continues to be a major clinical obstacle. Previously, our group demonstrated that as breast cancer cells transition from hormone-dependent to hormone-independent, they are associated with increased growth factor signaling, enhanced cellular motility, and the epithelial to mesenchymal transition (EMT). Given the complexity of cancer stem cells (CSC) and their implications on endocrine resistance and EMT, we sought to understand their contribution towards the development of aromatase inhibitor resistant breast cancer. Cells cultured three dimensionally as mammospheres are enriched for CSCs and more accurately recapitulates tumors in vivo. Therefore, a global proteomic analysis was conducted using letrozole resistant breast cancer cells (LTLT-Ca) mammospheres and compared to their adherent counterparts. Results demonstrated over 1000 proteins with quantitative abundance ratios were identified. Among the quantified proteins, 359 were significantly altered (p < 0.05), where 173 were upregulated and 186 downregulated (p < 0.05, fold change >1.20). Notably, midasin, a chaperone protein required for maturation and nuclear export of the pre-60S ribosome was increased 35-fold. Protein expression analyses confirmed midasin is ubiquitously expressed in normal tissue but is overexpressed in lobular and ductal breast carcinoma tissue as well as ER+ and ER- breast cancer cell lines. Functional enrichment analyses indicated that 19 gene ontology terms and one KEGG pathway were over-represented by the down-regulated proteins and both were associated with protein synthesis. Increased midasin was strongly correlated with decreased relapse free survival in hormone independent breast cancer. For the first time, we characterized the global proteomic signature of CSC-enriched letrozole-resistant cells associated with protein synthesis, which may implicate a role for midasin in endocrine resistance.
Collapse
Affiliation(s)
- Karen M Gallegos
- Division of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL, United States
| | - Jankiben R Patel
- Division of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL, United States
| | - Shawn D Llopis
- Division of Basic Pharmaceutical Sciences, College of Pharmacy, Xavier University of Louisiana, New Orleans, LA, United States
| | - Rashidra R Walker
- Division of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL, United States
| | - A Michael Davidson
- Division of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL, United States
| | - Wensheng Zhang
- Division of Mathematical and Physical Sciences, Department of Computer Science, College of Arts and Sciences, Xavier University of Louisiana, New Orleans, LA, United States
| | - Kun Zhang
- Division of Mathematical and Physical Sciences, Department of Computer Science, College of Arts and Sciences, Xavier University of Louisiana, New Orleans, LA, United States
| | - Syreeta L Tilghman
- Division of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL, United States
| |
Collapse
|
4
|
Native Chromatin Proteomics Reveals a Role for Specific Nucleoporins in Heterochromatin Organization and Maintenance. Mol Cell 2019; 77:51-66.e8. [PMID: 31784357 DOI: 10.1016/j.molcel.2019.10.018] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 08/19/2019] [Accepted: 10/11/2019] [Indexed: 12/31/2022]
Abstract
Spatially and functionally distinct domains of heterochromatin and euchromatin play important roles in the maintenance of chromosome stability and regulation of gene expression, but a comprehensive knowledge of their composition is lacking. Here, we develop a strategy for the isolation of native Schizosaccharomyces pombe heterochromatin and euchromatin fragments and analyze their composition by using quantitative mass spectrometry. The shared and euchromatin-specific proteomes contain proteins involved in DNA and chromatin metabolism and in transcription, respectively. The heterochromatin-specific proteome includes all proteins with known roles in heterochromatin formation and, in addition, is enriched for subsets of nucleoporins and inner nuclear membrane (INM) proteins, which associate with different chromatin domains. While the INM proteins are required for the integrity of the nucleolus, containing ribosomal DNA repeats, the nucleoporins are required for aggregation of heterochromatic foci and epigenetic inheritance. The results provide a comprehensive picture of heterochromatin-associated proteins and suggest a role for specific nucleoporins in heterochromatin function.
Collapse
|
5
|
Prattes M, Lo YH, Bergler H, Stanley RE. Shaping the Nascent Ribosome: AAA-ATPases in Eukaryotic Ribosome Biogenesis. Biomolecules 2019; 9:E715. [PMID: 31703473 PMCID: PMC6920918 DOI: 10.3390/biom9110715] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/04/2019] [Accepted: 11/05/2019] [Indexed: 02/08/2023] Open
Abstract
AAA-ATPases are molecular engines evolutionarily optimized for the remodeling of proteins and macromolecular assemblies. Three AAA-ATPases are currently known to be involved in the remodeling of the eukaryotic ribosome, a megadalton range ribonucleoprotein complex responsible for the translation of mRNAs into proteins. The correct assembly of the ribosome is performed by a plethora of additional and transiently acting pre-ribosome maturation factors that act in a timely and spatially orchestrated manner. Minimal disorder of the assembly cascade prohibits the formation of functional ribosomes and results in defects in proliferation and growth. Rix7, Rea1, and Drg1, which are well conserved across eukaryotes, are involved in different maturation steps of pre-60S ribosomal particles. These AAA-ATPases provide energy for the efficient removal of specific assembly factors from pre-60S particles after they have fulfilled their function in the maturation cascade. Recent structural and functional insights have provided the first glimpse into the molecular mechanism of target recognition and remodeling by Rix7, Rea1, and Drg1. Here we summarize current knowledge on the AAA-ATPases involved in eukaryotic ribosome biogenesis. We highlight the latest insights into their mechanism of mechano-chemical complex remodeling driven by advanced cryo-EM structures and the use of highly specific AAA inhibitors.
Collapse
Affiliation(s)
- Michael Prattes
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/EG, A-8010 Graz, Austria;
| | - Yu-Hua Lo
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, Durham, NC 27709, USA;
| | - Helmut Bergler
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/EG, A-8010 Graz, Austria;
| | - Robin E. Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, Durham, NC 27709, USA;
| |
Collapse
|
6
|
Essential Saccharomyces cerevisiae genome instability suppressing genes identify potential human tumor suppressors. Proc Natl Acad Sci U S A 2019; 116:17377-17382. [PMID: 31409704 DOI: 10.1073/pnas.1906921116] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Gross Chromosomal Rearrangements (GCRs) play an important role in human diseases, including cancer. Although most of the nonessential Genome Instability Suppressing (GIS) genes in Saccharomyces cerevisiae are known, the essential genes in which mutations can cause increased GCR rates are not well understood. Here 2 S. cerevisiae GCR assays were used to screen a targeted collection of temperature-sensitive mutants to identify mutations that caused increased GCR rates. This identified 94 essential GIS (eGIS) genes in which mutations cause increased GCR rates and 38 candidate eGIS genes that encode eGIS1 protein-interacting or family member proteins. Analysis of TCGA data using the human genes predicted to encode the proteins and protein complexes implicated by the S. cerevisiae eGIS genes revealed a significant enrichment of mutations affecting predicted human eGIS genes in 10 of the 16 cancers analyzed.
Collapse
|
7
|
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.
Collapse
Affiliation(s)
- Jochen Baßler
- Biochemistry Center, University of Heidelberg, 69120 Heidelberg, Germany; ,
| | - Ed Hurt
- Biochemistry Center, University of Heidelberg, 69120 Heidelberg, Germany; ,
| |
Collapse
|
8
|
Chen Z, Suzuki H, Kobayashi Y, Wang AC, DiMaio F, Kawashima SA, Walz T, Kapoor TM. Structural Insights into Mdn1, an Essential AAA Protein Required for Ribosome Biogenesis. Cell 2018; 175:822-834.e18. [PMID: 30318141 DOI: 10.1016/j.cell.2018.09.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 07/23/2018] [Accepted: 09/10/2018] [Indexed: 12/20/2022]
Abstract
Mdn1 is an essential AAA (ATPase associated with various activities) protein that removes assembly factors from distinct precursors of the ribosomal 60S subunit. However, Mdn1's large size (∼5,000 amino acid [aa]) and its limited homology to other well-studied proteins have restricted our understanding of its remodeling function. Here, we present structures for S. pombe Mdn1 in the presence of AMPPNP at up to ∼4 Å or ATP plus Rbin-1, a chemical inhibitor, at ∼8 Å resolution. These data reveal that Mdn1's MIDAS domain is tethered to its ring-shaped AAA domain through an ∼20 nm long structured linker and a flexible ∼500 aa Asp/Glu-rich motif. We find that the MIDAS domain, which also binds other ribosome-assembly factors, docks onto the AAA ring in a nucleotide state-specific manner. Together, our findings reveal how conformational changes in the AAA ring can be directly transmitted to the MIDAS domain and thereby drive the targeted release of assembly factors from ribosomal 60S-subunit precursors.
Collapse
Affiliation(s)
- Zhen Chen
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY 10065, USA
| | - Hiroshi Suzuki
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, NY 10065, USA
| | - Yuki Kobayashi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 1130033, Japan
| | - Ashley C Wang
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY 10065, USA
| | - Frank DiMaio
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Shigehiro A Kawashima
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 1130033, Japan
| | - Thomas Walz
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, NY 10065, USA.
| | - Tarun M Kapoor
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY 10065, USA.
| |
Collapse
|
9
|
Zisser G, Ohmayer U, Mauerhofer C, Mitterer V, Klein I, Rechberger GN, Wolinski H, Prattes M, Pertschy B, Milkereit P, Bergler H. Viewing pre-60S maturation at a minute's timescale. Nucleic Acids Res 2018; 46:3140-3151. [PMID: 29294095 PMCID: PMC5888160 DOI: 10.1093/nar/gkx1293] [Citation(s) in RCA: 17] [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: 08/22/2017] [Revised: 11/30/2017] [Accepted: 12/18/2017] [Indexed: 12/03/2022] Open
Abstract
The formation of ribosomal subunits is a highly dynamic process that is initiated in the nucleus and involves more than 200 trans-acting factors, some of which accompany the pre-ribosomes into the cytoplasm and have to be recycled into the nucleus. The inhibitor diazaborine prevents cytoplasmic release and recycling of shuttling pre-60S maturation factors by inhibiting the AAA-ATPase Drg1. The failure to recycle these proteins results in their depletion in the nucleolus and halts the pathway at an early maturation step. Here, we made use of the fast onset of inhibition by diazaborine to chase the maturation path in real-time from 27SA2 pre-rRNA containing pre-ribosomes localized in the nucleolus up to nearly mature 60S subunits shortly after their export into the cytoplasm. This allows for the first time to put protein assembly and disassembly reactions as well as pre-rRNA processing into a chronological context unraveling temporal and functional linkages during ribosome maturation.
Collapse
Affiliation(s)
- Gertrude Zisser
- Institute of Molecular Biosciences, Humboldtstrasse 50/EG, University of Graz, A-8010 Graz, Austria
| | - Uli Ohmayer
- Lehrstuhl Biochemie III, University Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Christina Mauerhofer
- Institute of Molecular Biosciences, Humboldtstrasse 50/EG, University of Graz, A-8010 Graz, Austria
| | - Valentin Mitterer
- Institute of Molecular Biosciences, Humboldtstrasse 50/EG, University of Graz, A-8010 Graz, Austria
| | - Isabella Klein
- Institute of Molecular Biosciences, Humboldtstrasse 50/EG, University of Graz, A-8010 Graz, Austria
| | - Gerald N Rechberger
- Institute of Molecular Biosciences, Humboldtstrasse 50/EG, University of Graz, A-8010 Graz, Austria
- Omics Center Graz, BioTechMed-Graz, A-8010 Graz, Austria
| | - Heimo Wolinski
- Institute of Molecular Biosciences, Humboldtstrasse 50/EG, University of Graz, A-8010 Graz, Austria
- BioTechMed-Graz, A-8010 Graz, Austria
| | - Michael Prattes
- Institute of Molecular Biosciences, Humboldtstrasse 50/EG, University of Graz, A-8010 Graz, Austria
| | - Brigitte Pertschy
- Institute of Molecular Biosciences, Humboldtstrasse 50/EG, University of Graz, A-8010 Graz, Austria
- BioTechMed-Graz, A-8010 Graz, Austria
| | - Philipp Milkereit
- Lehrstuhl Biochemie III, University Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Helmut Bergler
- Institute of Molecular Biosciences, Humboldtstrasse 50/EG, University of Graz, A-8010 Graz, Austria
- BioTechMed-Graz, A-8010 Graz, Austria
| |
Collapse
|
10
|
Martins T, Eusebio N, Correia A, Marinho J, Casares F, Pereira PS. TGFβ/Activin signalling is required for ribosome biogenesis and cell growth in Drosophila salivary glands. Open Biol 2017; 7:rsob.160258. [PMID: 28123053 PMCID: PMC5303274 DOI: 10.1098/rsob.160258] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 12/16/2016] [Indexed: 12/30/2022] Open
Abstract
Signalling by TGFβ superfamily factors plays an important role in tissue growth and cell proliferation. In Drosophila, the activity of the TGFβ/Activin signalling branch has been linked to the regulation of cell growth and proliferation, but the cellular and molecular basis for these functions are not fully understood. In this study, we show that both the RII receptor Punt (Put) and the R-Smad Smad2 are strongly required for cell and tissue growth. Knocking down the expression of Put or Smad2 in salivary glands causes alterations in nucleolar structure and functions. Cells with decreased TGFβ/Activin signalling accumulate intermediate pre-rRNA transcripts containing internal transcribed spacer 1 regions accompanied by the nucleolar retention of ribosomal proteins. Thus, our results show that TGFβ/Activin signalling is required for ribosomal biogenesis, a key aspect of cellular growth control. Importantly, overexpression of Put enhanced cell growth induced by Drosophila Myc, a well-characterized inducer of nucleolar hypertrophy and ribosome biogenesis.
Collapse
Affiliation(s)
- Torcato Martins
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto 4150-180, Portugal .,Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto 4150-180, Portugal.,Cell Cycle Development Group, Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK
| | - Nadia Eusebio
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto 4150-180, Portugal.,Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto 4150-180, Portugal
| | - Andreia Correia
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto 4150-180, Portugal.,Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto 4150-180, Portugal
| | - Joana Marinho
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto 4150-180, Portugal.,Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto 4150-180, Portugal
| | - Fernando Casares
- Centro Andaluz de Biología del Desarrollo (CABD), CSIC-JA-Universidad Pablo de Olavide. Ctra. de Utrera km1, Seville 41013, Spain
| | - Paulo S Pereira
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto 4150-180, Portugal .,Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto 4150-180, Portugal
| |
Collapse
|
11
|
Chen W, Xie Z, Yang F, Ye K. Stepwise assembly of the earliest precursors of large ribosomal subunits in yeast. Nucleic Acids Res 2017; 45:6837-6847. [PMID: 28402444 PMCID: PMC5499802 DOI: 10.1093/nar/gkx254] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/04/2017] [Indexed: 12/15/2022] Open
Abstract
Small ribosomal subunits are co-transcriptionally assembled on the nascent precursor rRNA in Saccharomyces cerevisiae. It is unknown how the highly intertwined structure of 60S large ribosomal subunits is initially formed. Here, we affinity purified and analyzed a series of pre-60S particles assembled in vivo on plasmid-encoded pre-rRNA fragments of increasing lengths, revealing a spatiotemporal assembly map for 34 trans-acting assembly factors (AFs), 30 ribosomal proteins and 5S rRNA. The gradual association of AFs and ribosomal proteins with the pre-rRNA fragments strongly supports that the pre-60S is co-transcriptionally, rather than post-transcriptionally, assembled. The internal and external transcribed spacers ITS1, ITS2 and 3΄ ETS in pre-rRNA must be processed in pre-60S. We show that the processing machineries for ITS1 and ITS2 are primarily recruited by the 5΄ and 3΄ halves of pre-27S RNA, respectively. Nevertheless, processing of both ITS1 and ITS2 requires a complete 25S region. The 3΄ ETS plays a minor role in ribosome assembly, but is important for efficient rRNA processing and ribosome maturation. We also identified a distinct pre-60S state occurring before ITS2 processing. Our data reveal the elusive co-transcriptional assembly pathway of large ribosomal subunit.
Collapse
Affiliation(s)
- Wu Chen
- College of Biological Sciences, China Agricultural University, Beijing 100193, China.,National Institute of Biological Sciences, Beijing 102206, China.,Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhensheng Xie
- Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fuquan Yang
- Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Keqiong Ye
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
12
|
Tomecki R, Sikorski PJ, Zakrzewska-Placzek M. Comparison of preribosomal RNA processing pathways in yeast, plant and human cells - focus on coordinated action of endo- and exoribonucleases. FEBS Lett 2017; 591:1801-1850. [PMID: 28524231 DOI: 10.1002/1873-3468.12682] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 05/14/2017] [Accepted: 05/15/2017] [Indexed: 12/17/2022]
Abstract
Proper regulation of ribosome biosynthesis is mandatory for cellular adaptation, growth and proliferation. Ribosome biogenesis is the most energetically demanding cellular process, which requires tight control. Abnormalities in ribosome production have severe consequences, including developmental defects in plants and genetic diseases (ribosomopathies) in humans. One of the processes occurring during eukaryotic ribosome biogenesis is processing of the ribosomal RNA precursor molecule (pre-rRNA), synthesized by RNA polymerase I, into mature rRNAs. It must not only be accurate but must also be precisely coordinated with other phenomena leading to the synthesis of functional ribosomes: RNA modification, RNA folding, assembly with ribosomal proteins and nucleocytoplasmic RNP export. A multitude of ribosome biogenesis factors ensure that these events take place in a correct temporal order. Among them are endo- and exoribonucleases involved in pre-rRNA processing. Here, we thoroughly present a wide spectrum of ribonucleases participating in rRNA maturation, focusing on their biochemical properties, regulatory mechanisms and substrate specificity. We also discuss cooperation between various ribonucleolytic activities in particular stages of pre-rRNA processing, delineating major similarities and differences between three representative groups of eukaryotes: yeast, plants and humans.
Collapse
Affiliation(s)
- Rafal Tomecki
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.,Department of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Poland
| | | | | |
Collapse
|
13
|
Biedka S, Wu S, LaPeruta AJ, Gao N, Woolford JL. Insights into remodeling events during eukaryotic large ribosomal subunit assembly provided by high resolution cryo-EM structures. RNA Biol 2017; 14:1306-1313. [PMID: 28267408 PMCID: PMC5711468 DOI: 10.1080/15476286.2017.1297914] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Ribosomes are responsible for translating the genome, in the form of mRNA, into the proteome in all organisms. Biogenesis of ribosomes in eukaryotes is a complex process involving numerous remodeling events driven in part by the concerted actions of hundreds of protein assembly factors. A major challenge in studying eukaryotic ribosome assembly has, until recently, been a lack of structural data to facilitate understanding of the conformational and compositional changes the pre-ribosome undergoes during its construction. Cryo-electron microscopy (cryo-EM) has begun filling these gaps; recent advances in cryo-EM have enabled the determination of several high resolution pre-ribosome structures. This review focuses mainly on lessons learned from the study of pre-60S particles purified from yeast using the assembly factor Nog2 as bait. These Nog2 particles provide insight into many aspects of nuclear stages of 60S subunit assembly, including construction of major 60S subunit functional centers and processing of the ITS2 spacer RNA.
Collapse
Affiliation(s)
- Stephanie Biedka
- a Department of Biological Sciences , Carnegie Mellon University , Pittsburgh , PA , USA
| | - Shan Wu
- b Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University , Beijing , China
| | - Amber J LaPeruta
- a Department of Biological Sciences , Carnegie Mellon University , Pittsburgh , PA , USA
| | - Ning Gao
- b Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University , Beijing , China
| | - John L Woolford
- a Department of Biological Sciences , Carnegie Mellon University , Pittsburgh , PA , USA
| |
Collapse
|
14
|
The Mutation of Glu at Amino Acid 3838 of AtMDN1 Provokes Pleiotropic Developmental Phenotypes in Arabidopsis. Sci Rep 2016; 6:36446. [PMID: 27824150 PMCID: PMC5099923 DOI: 10.1038/srep36446] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 10/13/2016] [Indexed: 02/06/2023] Open
Abstract
MDN1/Rea1, as an AAA-type ATPase, is predicted to be the largest protein involved in pre-ribosome maturation in most organisms. However, its function in plant growth and development is poorly understood. Here, we characterized a novel Arabidopsis mutant, dwarf & short root (dsr) 1, which shows pleiotropic developmental phenotypes, such as slow germination, short root, dwarf shoot, and reduced seed set under normal growth conditions. Using positional cloning, we revealed that the AtMDN1 function is impaired by a ‘glutamic acid’ to ‘lysine’ change at position 3838 of the amino acid sequence in dsr1. Multiple sequence alignment analysis revealed that the mutated Glu residue, which located in the linker domain of AtMDN1, is extremely conserved among organisms. AtMDN1 is expressed in various tissues, particularly in the shoot apex and root tip. Moreover, the results of transcript profile analyses showed that the dysfunction of AtMDN1 in dsr1 impairs the expression of genes related to plant growth and development, which is tightly associated with the pleiotropic phenotypes of dsr1. Thus, we concluded that the Glu residue plays a vital role in maintaining AtMDN1 functions, which are essential for plant growth and development.
Collapse
|
15
|
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: 51] [Impact Index Per Article: 5.7] [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.
Collapse
Affiliation(s)
- Basil J Greber
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California 94720-3220, USA
| |
Collapse
|
16
|
Potent, Reversible, and Specific Chemical Inhibitors of Eukaryotic Ribosome Biogenesis. Cell 2016; 167:512-524.e14. [PMID: 27667686 PMCID: PMC5116814 DOI: 10.1016/j.cell.2016.08.070] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 07/14/2016] [Accepted: 08/26/2016] [Indexed: 11/21/2022]
Abstract
All cellular proteins are synthesized by ribosomes, whose biogenesis in eukaryotes is a complex multi-step process completed within minutes. Several chemical inhibitors of ribosome function are available and used as tools or drugs. By contrast, we lack potent validated chemical probes to analyze the dynamics of eukaryotic ribosome assembly. Here, we combine chemical and genetic approaches to discover ribozinoindoles (or Rbins), potent and reversible triazinoindole-based inhibitors of eukaryotic ribosome biogenesis. Analyses of Rbin sensitivity and resistance conferring mutations in fission yeast, along with biochemical assays with recombinant proteins, provide evidence that Rbins’ physiological target is Midasin, an essential ∼540-kDa AAA+ (ATPases associated with diverse cellular activities) protein. Using Rbins to acutely inhibit or activate Midasin function, in parallel experiments with inhibitor-sensitive or inhibitor-resistant cells, we uncover Midasin’s role in assembling Nsa1 particles, nucleolar precursors of the 60S subunit. Together, our findings demonstrate that Rbins are powerful probes for eukaryotic ribosome assembly. Ribozinoindoles are potent chemical inhibitors of eukaryotic ribosome assembly Activity of four of Mdn1’s six ATPase sites is likely needed for cell growth Ribozinoindoles inhibit recombinant full-length Mdn1’s ATPase activity in vitro Assembly of Nsa1 particles, precursors of the 60S subunit, depends on Mdn1
Collapse
|
17
|
Huang Y, Amin A, Qin Y, Wang Z, Jiang H, Liang L, Shi L, Liang C. A Role of hIPI3 in DNA Replication Licensing in Human Cells. PLoS One 2016; 11:e0151803. [PMID: 27057756 PMCID: PMC4825987 DOI: 10.1371/journal.pone.0151803] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/06/2016] [Indexed: 01/08/2023] Open
Abstract
The yeast Ipi3p is required for DNA replication and cell viability in Sacharomyces cerevisiae. It is an essential component of the Rix1 complex (Rix1p/Ipi2p-Ipi1p-Ipi3p) that is required for the processing of 35S pre-rRNA in pre-60S ribosomal particles and for the initiation of DNA replication. The human IPI3 homolog is WDR18 (WD repeat domain 18), which shares significant homology with yIpi3p. Here we report that knockdown of hIPI3 resulted in substantial defects in the chromatin association of the MCM complex, DNA replication, cell cycle progression and cell proliferation. Importantly, hIPI3 silencing did not result in a reduction of the protein level of hCDC6, hMCM7, or the ectopically expressed GFP protein, indicating that protein synthesis was not defective in the same time frame of the DNA replication and cell cycle defects. Furthermore, the mRNA and protein levels of hIPI3 fluctuate in the cell cycle, with the highest levels from M phase to early G1 phase, similar to other pre-replicative (pre-RC) proteins. Moreover, hIPI3 interacts with other replication-initiation proteins, co-localizes with hMCM7 in the nucleus, and is important for the nuclear localization of hMCM7. We also found that hIPI3 preferentially binds to the origins of DNA replication including those at the c-Myc, Lamin-B2 and β-Globin loci. These results indicate that hIPI3 is involved in human DNA replication licensing independent of its role in ribosome biogenesis.
Collapse
Affiliation(s)
- Yining Huang
- Biomedical Research Institute, Shenzhen-PKU-HKUST Medical Center, Shenzhen, China
- Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
- HKUST Fok Ying Tung Research Institute, Guangzhou, China
| | - Aftab Amin
- Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Yan Qin
- Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Ziyi Wang
- Biomedical Research Institute, Shenzhen-PKU-HKUST Medical Center, Shenzhen, China
- Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
- HKUST Fok Ying Tung Research Institute, Guangzhou, China
| | - Huadong Jiang
- Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Lu Liang
- Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Linjing Shi
- Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Chun Liang
- Biomedical Research Institute, Shenzhen-PKU-HKUST Medical Center, Shenzhen, China
- Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
- HKUST Fok Ying Tung Research Institute, Guangzhou, China
- Intelgen Ltd., Hong Kong-Guangzhou-Foshan, China
- * E-mail:
| |
Collapse
|
18
|
|
19
|
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: 8.9] [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.
Collapse
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
| |
Collapse
|
20
|
Baßler J, Paternoga H, Holdermann I, Thoms M, Granneman S, Barrio-Garcia C, Nyarko A, Lee W, Stier G, Clark SA, Schraivogel D, Kallas M, Beckmann R, Tollervey D, Barbar E, Sinning I, Hurt E. A network of assembly factors is involved in remodeling rRNA elements during preribosome maturation. ACTA ACUST UNITED AC 2014; 207:481-98. [PMID: 25404745 PMCID: PMC4242840 DOI: 10.1083/jcb.201408111] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Eukaryotic ribosome biogenesis involves ∼200 assembly factors, but how these contribute to ribosome maturation is poorly understood. Here, we identify a network of factors on the nascent 60S subunit that actively remodels preribosome structure. At its hub is Rsa4, a direct substrate of the force-generating ATPase Rea1. We show that Rsa4 is connected to the central protuberance by binding to Rpl5 and to ribosomal RNA (rRNA) helix 89 of the nascent peptidyl transferase center (PTC) through Nsa2. Importantly, Nsa2 binds to helix 89 before relocation of helix 89 to the PTC. Structure-based mutations of these factors reveal the functional importance of their interactions for ribosome assembly. Thus, Rsa4 is held tightly in the preribosome and can serve as a "distribution box," transmitting remodeling energy from Rea1 into the developing ribosome. We suggest that a relay-like factor network coupled to a mechano-enzyme is strategically positioned to relocate rRNA elements during ribosome maturation.
Collapse
Affiliation(s)
- Jochen Baßler
- Biochemistry Center of Heidelberg University, INF328, D-69120 Heidelberg, Germany
| | - Helge Paternoga
- Biochemistry Center of Heidelberg University, INF328, D-69120 Heidelberg, Germany
| | - Iris Holdermann
- Biochemistry Center of Heidelberg University, INF328, D-69120 Heidelberg, Germany
| | - Matthias Thoms
- Biochemistry Center of Heidelberg University, INF328, D-69120 Heidelberg, Germany
| | - Sander Granneman
- Centre for Synthetic and Systems Biology (SynthSys) and Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, Scotland, UK
| | - Clara Barrio-Garcia
- Gene Center, Department of Chemistry and Biochemistry, University of Munich, 80539 Munich, Germany
| | - Afua Nyarko
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331
| | - Woonghee Lee
- National Magnetic Resonance Facility; Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706
| | - Gunter Stier
- Biochemistry Center of Heidelberg University, INF328, D-69120 Heidelberg, Germany
| | - Sarah A Clark
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331
| | - Daniel Schraivogel
- Biochemistry Center of Heidelberg University, INF328, D-69120 Heidelberg, Germany
| | - Martina Kallas
- Biochemistry Center of Heidelberg University, INF328, D-69120 Heidelberg, Germany
| | - Roland Beckmann
- Gene Center, Department of Chemistry and Biochemistry, University of Munich, 80539 Munich, Germany
| | - David Tollervey
- Centre for Synthetic and Systems Biology (SynthSys) and Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, Scotland, UK
| | - Elisar Barbar
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331
| | - Irmi Sinning
- Biochemistry Center of Heidelberg University, INF328, D-69120 Heidelberg, Germany
| | - Ed Hurt
- Biochemistry Center of Heidelberg University, INF328, D-69120 Heidelberg, Germany
| |
Collapse
|
21
|
Henras AK, Plisson-Chastang C, O'Donohue MF, Chakraborty A, Gleizes PE. An overview of pre-ribosomal RNA processing in eukaryotes. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 6:225-42. [PMID: 25346433 PMCID: PMC4361047 DOI: 10.1002/wrna.1269] [Citation(s) in RCA: 421] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 08/04/2014] [Accepted: 08/29/2014] [Indexed: 12/23/2022]
Abstract
Ribosomal RNAs are the most abundant and universal noncoding RNAs in living organisms. In eukaryotes, three of the four ribosomal RNAs forming the 40S and 60S subunits are borne by a long polycistronic pre-ribosomal RNA. A complex sequence of processing steps is required to gradually release the mature RNAs from this precursor, concomitant with the assembly of the 79 ribosomal proteins. A large set of trans-acting factors chaperone this process, including small nucleolar ribonucleoparticles. While yeast has been the gold standard for studying the molecular basis of this process, recent technical advances have allowed to further define the mechanisms of ribosome biogenesis in animals and plants. This renewed interest for a long-lasting question has been fueled by the association of several genetic diseases with mutations in genes encoding both ribosomal proteins and ribosome biogenesis factors, and by the perspective of new anticancer treatments targeting the mechanisms of ribosome synthesis. A consensus scheme of pre-ribosomal RNA maturation is emerging from studies in various kinds of eukaryotic organisms. However, major differences between mammalian and yeast pre-ribosomal RNA processing have recently come to light. WIREs RNA 2015, 6:225–242. doi: 10.1002/wrna.1269
Collapse
Affiliation(s)
- Anthony K Henras
- Laboratoire de Biologie Moléculaire Eucaryote, Université de Toulouse-Paul Sabatier CNRS, UMR 5099, Toulouse, France
| | | | | | | | | |
Collapse
|
22
|
Thomson E, Ferreira-Cerca S, Hurt E. Eukaryotic ribosome biogenesis at a glance. J Cell Sci 2014; 126:4815-21. [PMID: 24172536 DOI: 10.1242/jcs.111948] [Citation(s) in RCA: 228] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Ribosomes play a pivotal role in the molecular life of every cell. Moreover, synthesis of ribosomes is one of the most energetically demanding of all cellular processes. In eukaryotic cells, ribosome biogenesis requires the coordinated activity of all three RNA polymerases and the orchestrated work of many (>200) transiently associated ribosome assembly factors. The biogenesis of ribosomes is a tightly regulated activity and it is inextricably linked to other fundamental cellular processes, including growth and cell division. Furthermore, recent studies have demonstrated that defects in ribosome biogenesis are associated with several hereditary diseases. In this Cell Science at a Glance article and the accompanying poster, we summarise the current knowledge on eukaryotic ribosome biogenesis, with an emphasis on the yeast model system.
Collapse
Affiliation(s)
- Emma Thomson
- Biochemistry Center (BZH), University of Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | | | | |
Collapse
|
23
|
Ribosome assembly factors Pwp1 and Nop12 are important for folding of 5.8S rRNA during ribosome biogenesis in Saccharomyces cerevisiae. Mol Cell Biol 2014; 34:1863-77. [PMID: 24636992 DOI: 10.1128/mcb.01322-13] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Previous work from our lab suggests that a group of interdependent assembly factors (A(3) factors) is necessary to create early, stable preribosomes. Many of these proteins bind at or near internal transcribed spacer 2 (ITS2), but in their absence, ITS1 is not removed from rRNA, suggesting long-range communication between these two spacers. By comparing the nonessential assembly factors Nop12 and Pwp1, we show that misfolding of rRNA is sufficient to perturb early steps of biogenesis, but it is the lack of A(3) factors that results in turnover of early preribosomes. Deletion of NOP12 significantly inhibits 27SA(3) pre-rRNA processing, even though the A(3) factors are present in preribosomes. Furthermore, pre-rRNAs are stable, indicating that the block in processing is not sufficient to trigger turnover. This is in contrast to the absence of Pwp1, in which the A(3) factors are not present and pre-rRNAs are unstable. In vivo RNA structure probing revealed that the pre-rRNA processing defects are due to misfolding of 5.8S rRNA. In the absence of Nop12 and Pwp1, rRNA helix 5 is not stably formed. Interestingly, the absence of Nop12 results in the formation of an alternative yet unproductive helix 5 when cells are grown at low temperatures.
Collapse
|
24
|
Abstract
Construction of the eukaryotic ribosome begins in the nucleolus and requires >300 evolutionarily conserved nonribosomal trans-acting factors, which transiently associate with preribosomal subunits at distinct assembly stages. A subset of trans-acting and transport factors passage assembled preribosomal subunits in a functionally inactive state through the nuclear pore complexes (NPC) into the cytoplasm, where they undergo final maturation before initiating translation. Here, we summarize the repertoire of tools developed in the model organism budding yeast that are spearheading the functional analyses of trans-acting factors involved in the assembly and intracellular transport of preribosomal subunits. We elaborate on different GFP-tagged ribosomal protein reporters and a pre-rRNA reporter that reliably monitors the movement of preribosomal particles from the nucleolus to cytoplasm. We discuss the powerful yeast heterokaryon assay, which can be employed to uncover shuttling trans-acting factors that need to accompany preribosomal subunits to the cytoplasm to be released prior to initiating translation. Moreover, we present two biochemical approaches, namely sucrose gradient analyses and tandem affinity purification, that are rapidly facilitating the uncovering of regulatory processes that control the compositional dynamics of trans-acting factors on maturing preribosomal particles. Altogether, these approaches when combined with traditional analytical biochemistry, targeted proteomics and structural methodologies, will contribute to the dissection of the assembly and intracellular transport of preribosomal subunits, as well as other macromolecular assemblies that influence diverse biological pathways.
Collapse
MESH Headings
- Biological Transport/genetics
- Green Fluorescent Proteins/genetics
- In Situ Hybridization, Fluorescence/methods
- Karyopherins/genetics
- Mass Spectrometry/methods
- Microscopy, Fluorescence/methods
- Nuclear Pore/genetics
- Nuclear Pore/metabolism
- Nucleolus Organizer Region/genetics
- RNA, Ribosomal/biosynthesis
- RNA, Ribosomal/genetics
- Receptors, Cytoplasmic and Nuclear/genetics
- Ribosome Subunits, Large, Eukaryotic/genetics
- Ribosome Subunits, Large, Eukaryotic/metabolism
- Ribosome Subunits, Small, Eukaryotic/genetics
- Ribosome Subunits, Small, Eukaryotic/metabolism
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
- Ultracentrifugation/methods
- Exportin 1 Protein
Collapse
Affiliation(s)
- Martin Altvater
- Institute of Biochemistry (IBC), ETH Zürich, Otto-Stern-Weg 3, Zurich, Switzerland; MLS Program, Life Science Zurich Graduate School, Winterthurerstrasse 190, Zurich, Switzerland
| | - Sabina Schütz
- Institute of Biochemistry (IBC), ETH Zürich, Otto-Stern-Weg 3, Zurich, Switzerland; MLS Program, Life Science Zurich Graduate School, Winterthurerstrasse 190, Zurich, Switzerland
| | - Yiming Chang
- Institute of Biochemistry (IBC), ETH Zürich, Otto-Stern-Weg 3, Zurich, Switzerland
| | - Vikram Govind Panse
- Institute of Biochemistry (IBC), ETH Zürich, Otto-Stern-Weg 3, Zurich, Switzerland
| |
Collapse
|
25
|
Meinel DM, Burkert-Kautzsch C, Kieser A, O'Duibhir E, Siebert M, Mayer A, Cramer P, Söding J, Holstege FCP, Sträßer K. Recruitment of TREX to the transcription machinery by its direct binding to the phospho-CTD of RNA polymerase II. PLoS Genet 2013; 9:e1003914. [PMID: 24244187 PMCID: PMC3828145 DOI: 10.1371/journal.pgen.1003914] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 09/09/2013] [Indexed: 12/31/2022] Open
Abstract
Messenger RNA (mRNA) synthesis and export are tightly linked, but the molecular mechanisms of this coupling are largely unknown. In Saccharomyces cerevisiae, the conserved TREX complex couples transcription to mRNA export and mediates mRNP formation. Here, we show that TREX is recruited to the transcription machinery by direct interaction of its subcomplex THO with the serine 2-serine 5 (S2/S5) diphosphorylated CTD of RNA polymerase II. S2 and/or tyrosine 1 (Y1) phosphorylation of the CTD is required for TREX occupancy in vivo, establishing a second interaction platform necessary for TREX recruitment in addition to RNA. Genome-wide analyses show that the occupancy of THO and the TREX components Sub2 and Yra1 increases from the 5' to the 3' end of the gene in accordance with the CTD S2 phosphorylation pattern. Importantly, in a mutant strain, in which TREX is recruited to genes but does not increase towards the 3' end, the expression of long transcripts is specifically impaired. Thus, we show for the first time that a 5'-3' increase of a protein complex is essential for correct expression of the genome. In summary, we provide insight into how the phospho-code of the CTD directs mRNP formation and export through TREX recruitment.
Collapse
Affiliation(s)
- Dominik M. Meinel
- Gene Center and Munich Center for Integrated Protein Science CIPSM at the Department of Biochemistry of the Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Cornelia Burkert-Kautzsch
- Gene Center and Munich Center for Integrated Protein Science CIPSM at the Department of Biochemistry of the Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Anja Kieser
- Gene Center and Munich Center for Integrated Protein Science CIPSM at the Department of Biochemistry of the Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Eoghan O'Duibhir
- Molecular Cancer Research, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Matthias Siebert
- Gene Center and Munich Center for Integrated Protein Science CIPSM at the Department of Biochemistry of the Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Andreas Mayer
- Gene Center and Munich Center for Integrated Protein Science CIPSM at the Department of Biochemistry of the Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Patrick Cramer
- Gene Center and Munich Center for Integrated Protein Science CIPSM at the Department of Biochemistry of the Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Johannes Söding
- Gene Center and Munich Center for Integrated Protein Science CIPSM at the Department of Biochemistry of the Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Frank C. P. Holstege
- Molecular Cancer Research, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Katja Sträßer
- Gene Center and Munich Center for Integrated Protein Science CIPSM at the Department of Biochemistry of the Ludwig-Maximilians-University of Munich, Munich, Germany
- * E-mail:
| |
Collapse
|
26
|
Hickey CM, Wilson NR, Hochstrasser M. Function and regulation of SUMO proteases. Nat Rev Mol Cell Biol 2013; 13:755-66. [PMID: 23175280 DOI: 10.1038/nrm3478] [Citation(s) in RCA: 506] [Impact Index Per Article: 42.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Covalent attachment of small ubiquitin-like modifier (SUMO) to proteins is highly dynamic, and both SUMO-protein conjugation and cleavage can be regulated. Protein desumoylation is carried out by SUMO proteases, which control cellular mechanisms ranging from transcription and cell division to ribosome biogenesis. Recent advances include the discovery of two novel classes of SUMO proteases, insights regarding SUMO protease specificity, and revelations of previously unappreciated SUMO protease functions in several key cellular pathways. These developments, together with new connections between SUMO proteases and the recently discovered SUMO-targeted ubiquitin ligases (STUbLs), make this an exciting period to study these enzymes.
Collapse
Affiliation(s)
- Christopher M Hickey
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, Connecticut 06520, USA
| | | | | |
Collapse
|
27
|
Single-molecule analysis of gene expression using two-color RNA labeling in live yeast. Nat Methods 2012; 10:119-21. [PMID: 23263691 DOI: 10.1038/nmeth.2305] [Citation(s) in RCA: 229] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Accepted: 11/21/2012] [Indexed: 01/11/2023]
Abstract
Live-cell imaging of mRNA yields important insights into gene expression, but it has generally been limited to the labeling of one RNA species and has never been used to count single mRNAs over time in yeast. We demonstrate a two-color imaging system with single-molecule resolution using MS2 and PP7 RNA labeling. We use this methodology to measure intrinsic noise in mRNA levels and RNA polymerase II kinetics at a single gene.
Collapse
|
28
|
Bradatsch B, Leidig C, Granneman S, Gnädig M, Tollervey D, Böttcher B, Beckmann R, Hurt E. Structure of the pre-60S ribosomal subunit with nuclear export factor Arx1 bound at the exit tunnel. Nat Struct Mol Biol 2012; 19:1234-41. [PMID: 23142978 PMCID: PMC3678077 DOI: 10.1038/nsmb.2438] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 10/09/2012] [Indexed: 12/24/2022]
Abstract
Preribosomal particles evolve in the nucleus through transient interaction with biogenesis factors before export to the cytoplasm. Here, we report the architecture of the late pre-60S particle, purified from Saccharomyces cerevisiae, through Arx1, a nuclear export factor with structural homology to methionine aminopeptidases, or its binding partner Alb1. Cryo-EM reconstruction of the Arx1 particle at 11.9-Å resolution reveals regions of extra density on the pre-60S particle attributed to associated biogenesis factors, confirming the immature state of the nascent subunit. One of these densities could be unambiguously assigned to Arx1. Immunoelectron microscopy and UV cross-linking localize Arx1 close to the ribosomal exit tunnel, in direct contact with ES27, a highly dynamic eukaryotic rRNA expansion segment. The binding of Arx1 at the exit tunnel may position this export factor to prevent premature recruitment of ribosome-associated factors active during translation.
Collapse
|
29
|
Huo L, Wu R, Yu Z, Zhai Y, Yang X, Chan TC, Yeung JTF, Kan J, Liang C. The Rix1 (Ipi1p-2p-3p) complex is a critical determinant of DNA replication licensing independent of their roles in ribosome biogenesis. Cell Cycle 2012; 11:1325-39. [PMID: 22421151 DOI: 10.4161/cc.19709] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Several replication-initiation proteins are assembled stepwise onto replicators to form pre-replicative complexes (pre-RCs) to license eukaryotic DNA replication. We performed a yeast functional proteomic screen and identified the Rix1 complex members (Ipi1p-Ipi2p/Rix1-Ipi3p) as pre-RC components and critical determinants of replication licensing and replication-initiation frequency. Ipi3p interacts with pre-RC proteins, binds chromatin predominantly at ARS sequences in a cell cycle-regulated and ORC- and Noc3p-dependent manner and is required for loading Cdc6p, Cdt1p and MCM onto chromatin to form pre-RC during the M-to-G₁ transition and for pre-RC maintenance in G₁ phase-independent of its role in ribosome biogenesis. Moreover, Ipi1p and Ipi2p, but not other ribosome biogenesis proteins Rea1p and Utp1p, are also required for pre-RC formation and maintenance, and Ipi1p, -2p and -3p are interdependent for their chromatin association and function in pre-RC formation. These results establish a new framework for the hierarchy of pre-RC proteins, where the Ipi1p-2p-3p complex provides a critical link between ORC-Noc3p and Cdc6p-Cdt1p-MCM in replication licensing.
Collapse
Affiliation(s)
- Lin Huo
- Division of Life Science, Center for Cancer Research and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Castle CD, Cassimere EK, Denicourt C. LAS1L interacts with the mammalian Rix1 complex to regulate ribosome biogenesis. Mol Biol Cell 2012; 23:716-28. [PMID: 22190735 PMCID: PMC3279398 DOI: 10.1091/mbc.e11-06-0530] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 11/14/2011] [Accepted: 12/13/2011] [Indexed: 01/02/2023] Open
Abstract
The coordination of RNA polymerase I transcription with pre-rRNA processing, preribosomal particle assembly, and nuclear export is a finely tuned process requiring the concerted actions of a number of accessory factors. However, the exact functions of some of these proteins and how they assemble in subcomplexes remain poorly defined. LAS1L was first described as a nucleolar protein required for maturation of the 60S preribosomal subunit. In this paper, we demonstrate that LAS1L interacts with PELP1, TEX10, and WDR18, the mammalian homologues of the budding yeast Rix1 complex, along with NOL9 and SENP3, to form a novel nucleolar complex that cofractionates with the 60S preribosomal subunit. Depletion of LAS1L-associated proteins results in a p53-dependent G1 arrest and leads to defects in processing of the pre-rRNA internal transcribed spacer 2 region. We further show that the nucleolar localization of this complex requires active RNA polymerase I transcription and the small ubiquitin-like modifier-specific protease SENP3. Taken together, our data identify a novel mammalian complex required for 60S ribosomal subunit synthesis, providing further insight into the intricate, yet poorly described, process of ribosome biogenesis in higher eukaryotes.
Collapse
Affiliation(s)
- Christopher D. Castle
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX 77030
| | - Erica K. Cassimere
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX 77030
| | - Catherine Denicourt
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX 77030
| |
Collapse
|
31
|
Kressler D, Hurt E, Bergler H, Baßler J. The power of AAA-ATPases on the road of pre-60S ribosome maturation--molecular machines that strip pre-ribosomal particles. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1823:92-100. [PMID: 21763358 PMCID: PMC3264779 DOI: 10.1016/j.bbamcr.2011.06.017] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 06/27/2011] [Accepted: 06/28/2011] [Indexed: 11/16/2022]
Abstract
The biogenesis of ribosomes is a fundamental cellular process, which provides the molecular machines that synthesize all cellular proteins. The assembly of eukaryotic ribosomes is a highly complex multi-step process that requires more than 200 ribosome biogenesis factors, which mediate a broad spectrum of maturation reactions. The participation of many energy-consuming enzymes (e.g. AAA-type ATPases, RNA helicases, and GTPases) in this process indicates that the expenditure of energy is required to drive ribosome assembly. While the precise function of many of these enzymes remains elusive, recent progress has revealed that the three AAA-type ATPases involved in 60S subunit biogenesis are specifically dedicated to the release and recycling of distinct biogenesis factors. In this review, we will highlight how the molecular power of yeast Drg1, Rix7, and Rea1 is harnessed to promote the release of their substrate proteins from evolving pre-60S particles and, where appropriate, discuss possible catalytic mechanisms.
Collapse
Affiliation(s)
- Dieter Kressler
- University of Fribourg, Department of Biology, Unit of Biochemistry, Chemin du Musée 10, 1700 Fribourg, Switzerland
| | - Ed Hurt
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Helmut Bergler
- Institut für Molekulare Biowissenschaften, Karl-Franzens Universität Graz, Humboldtstrasse 50, A-8010 Graz, Austria
| | - Jochen Baßler
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| |
Collapse
|
32
|
Dynamics of the putative RNA helicase Spb4 during ribosome assembly in Saccharomyces cerevisiae. Mol Cell Biol 2011; 31:4156-64. [PMID: 21825077 DOI: 10.1128/mcb.05436-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Spb4 is a putative ATP-dependent RNA helicase that is required for proper processing of 27SB pre-rRNAs and therefore for 60S ribosomal subunit biogenesis. To define the timing of association of this protein with preribosomal particles, we have studied the composition of complexes that copurify with Spb4 tagged by tandem affinity purification (TAP-tagged Spb4). These complexes contain mainly the 27SB pre-rRNAs and about 50 ribosome biogenesis proteins, primarily components of early pre-60S ribosomal particles. To a lesser extent, some protein factors of 90S preribosomal particles and the 35S and 27SA pre-rRNAs also copurify with TAP-tagged Spb4. Moreover, we have obtained by site-directed mutagenesis an allele that results in the R360A substitution in the conserved motif VI of the Spb4 helicase domain. This allele causes a dominant-negative phenotype when overexpressed in the wild-type strain. Cells expressing Spb4(R360A) display an accumulation of 35S and 27SB pre-rRNAs and a net 40S ribosomal subunit defect. TAP-tagged Spb4(R360A) displays a greater steady-state association with 90S preribosomal particles than TAP-tagged wild-type Spb4. Together, our data indicate that Spb4 is a component of early nucle(ol)ar pre-60S ribosomal particles containing 27SB pre-rRNA. Apparently, Spb4 binds 90S preribosomal particles and dissociates from pre-60S ribosomal particles after processing of 27SB pre-rRNA.
Collapse
|
33
|
The SUMO system controls nucleolar partitioning of a novel mammalian ribosome biogenesis complex. EMBO J 2011; 30:1067-78. [PMID: 21326211 DOI: 10.1038/emboj.2011.33] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Accepted: 01/21/2011] [Indexed: 11/08/2022] Open
Abstract
Ribosome biogenesis is a tightly controlled pathway that requires an intricate spatial and temporal interplay of protein networks. Most structural rRNA components are generated in the nucleolus and assembled into pre-ribosomal particles, which are transferred for further maturation to the nucleoplasm and cytoplasm. In metazoa, few regulatory components for these processes have been characterized. Previous work revealed a critical role for the SUMO-specific protease SENP3 in the nucleolar steps of ribosome biogenesis. We biochemically purified a SENP3-associated complex comprising PELP1, TEX10 and WDR18, and demonstrate that this complex is involved in maturation and nucleolar release of the large ribosomal subunit. We identified PELP1 and the PELP1-associated factor LAS1L as SENP3-sensitive targets of SUMO, and provide evidence that balanced SUMO conjugation/deconjugation determines the nucleolar partitioning of this complex. This defines the PELP1-TEX10-WDR18 complex as a regulator of ribosome biogenesis and suggests that its SUMO-controlled distribution coordinates the rate of ribosome formation. These findings contribute to the basic understanding of mammalian ribosome biogenesis and shed new light on the role of SUMO in this process.
Collapse
|
34
|
Phipps KR, Charette JM, Baserga SJ. The small subunit processome in ribosome biogenesis—progress and prospects. WILEY INTERDISCIPLINARY REVIEWS. RNA 2011; 2:1-21. [PMID: 21318072 PMCID: PMC3035417 DOI: 10.1002/wrna.57] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The small subunit (SSU) processome is a 2.2-MDa ribonucleoprotein complex involved in the processing, assembly, and maturation of the SSU of eukaryotic ribosomes. The identities of many of the factors involved in SSU biogenesis have been elucidated over the past 40 years. However, as our understanding increases, so do the number of questions about the nature of this complicated process. Cataloging the components is the first step toward understanding the molecular workings of a system. This review will focus on how identifying components of ribosome biogenesis has led to the knowledge of how these factors, protein and RNA alike, associate with one another into subcomplexes, with a concentration on the small ribosomal subunit. We will also explore how this knowledge of subcomplex assembly has informed our understanding of the workings of the ribosome synthesis system as a whole.
Collapse
MESH Headings
- Animals
- Eukaryota/genetics
- Eukaryota/metabolism
- Humans
- Models, Biological
- Models, Molecular
- Nucleic Acid Conformation
- Protein Modification, Translational/genetics
- RNA, Ribosomal, 18S/chemistry
- RNA, Ribosomal, 18S/metabolism
- RNA, Small Nucleolar/chemistry
- RNA, Small Nucleolar/metabolism
- Ribonucleoproteins/chemistry
- Ribonucleoproteins/metabolism
- Ribosome Subunits, Small/metabolism
- Ribosomes/metabolism
Collapse
Affiliation(s)
- Kathleen R. Phipps
- Depts. of Molecular Biophysics & Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
| | - J. Michael Charette
- Depts. of Molecular Biophysics & Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
- Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Susan J. Baserga
- Depts. of Molecular Biophysics & Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
- Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Genetics, Yale University School of Medicine, New Haven, CT 06520, USA
| |
Collapse
|
35
|
Granneman S, Petfalski E, Swiatkowska A, Tollervey D. Cracking pre-40S ribosomal subunit structure by systematic analyses of RNA-protein cross-linking. EMBO J 2010; 29:2026-36. [PMID: 20453830 PMCID: PMC2892368 DOI: 10.1038/emboj.2010.86] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Accepted: 04/14/2010] [Indexed: 12/21/2022] Open
Abstract
Understanding of eukaryotic ribosome synthesis has been slowed by a lack of structural data for the pre-ribosomal particles. We report rRNA-binding sites for six late-acting 40S ribosome synthesis factors, three of which cluster around the 3' end of the 18S rRNA in model 3D structures. Enp1 and Ltv1 were previously implicated in 'beak' structure formation during 40S maturation--and their binding sites indicate direct functions. The kinase Rio2, putative GTPase Tsr1 and dimethylase Dim1 bind sequences involved in tRNA interactions and mRNA decoding, indicating that their presence is incompatible with translation. The Dim1- and Tsr1-binding sites overlap with those of homologous Escherichia coli proteins, revealing conservation in assembly pathways. The primary binding sites for the 18S 3'-endonuclease Nob1 are distinct from its cleavage site and were unaltered by mutation of the catalytic PIN domain. Structure probing indicated that at steady state the cleavage site is likely unbound by Nob1 and flexible in the pre-rRNA. Nob1 binds before pre-rRNA cleavage, and we conclude that structural reorganization is needed to bring together the catalytic PIN domain and its target.
Collapse
Affiliation(s)
- Sander Granneman
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, Scotland, UK
| | - Elisabeth Petfalski
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, Scotland, UK
| | - Agata Swiatkowska
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, Scotland, UK
| | - David Tollervey
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, Scotland, UK
| |
Collapse
|
36
|
Driving ribosome assembly. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:673-83. [DOI: 10.1016/j.bbamcr.2009.10.009] [Citation(s) in RCA: 376] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Revised: 10/13/2009] [Accepted: 10/26/2009] [Indexed: 11/19/2022]
|
37
|
Cisterna B, Biggiogera M. Ribosome biogenesis: from structure to dynamics. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 284:67-111. [PMID: 20875629 DOI: 10.1016/s1937-6448(10)84002-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In this chapter we describe the status of the research concerning the nucleolus, the major nuclear body. The nucleolus has been recognized as a dynamic organelle with many more functions than one could imagine. In fact, in addition to its fundamental role in the biogenesis of preribosomes, the nucleolus takes part in many other cellular processes and functions, such as the cell-cycle control and the p53 pathway: the direct or indirect involvement of the nucleolus in these various processes makes it sensitive to their alteration. Moreover, it is worth noting that the different nucleolar factors participating to independent mechanisms show different dynamics of association/disassociation with the nucleolar body.
Collapse
Affiliation(s)
- Barbara Cisterna
- Laboratory of Cell Biology and Neurobiology, Department of Animal Biology, University of Pavia, Pavia, Italy
| | | |
Collapse
|
38
|
Abstract
Ribosome assembly is required for cell growth in all organisms. Classic in vitro work in bacteria has led to a detailed understanding of the biophysical, thermodynamic, and structural basis for the ordered and correct assembly of ribosomal proteins on ribosomal RNA. Furthermore, it has enabled reconstitution of active subunits from ribosomal RNA and proteins in vitro. Nevertheless, recent work has shown that eukaryotic ribosome assembly requires a large macromolecular machinery in vivo. Many of these assembly factors such as ATPases, GTPases, and kinases hydrolyze nucleotide triphosphates. Because these enzymes are likely regulatory proteins, much work to date has focused on understanding their role in the assembly process. Here, we review these factors, as well as other sources of energy, and their roles in the ribosome assembly process. In addition, we propose roles of energy-releasing enzymes in the assembly process, to explain why energy is used for a process that occurs largely spontaneously in bacteria. Finally, we use literature data to suggest testable models for how these enzymes could be used as targets for regulation of ribosome assembly.
Collapse
Affiliation(s)
- Bethany S Strunk
- Chemical Biology Doctoral Program, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
| | | |
Collapse
|
39
|
Rodríguez-Mateos M, García-Gómez JJ, Francisco-Velilla R, Remacha M, de la Cruz J, Ballesta JPG. Role and dynamics of the ribosomal protein P0 and its related trans-acting factor Mrt4 during ribosome assembly in Saccharomyces cerevisiae. Nucleic Acids Res 2009; 37:7519-32. [PMID: 19789271 PMCID: PMC2794172 DOI: 10.1093/nar/gkp806] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 09/08/2009] [Accepted: 09/11/2009] [Indexed: 11/25/2022] Open
Abstract
Mrt4 is a nucleolar component of the ribosome assembly machinery that shares notable similarity and competes for binding to the 25S rRNA GAR domain with the ribosomal protein P0. Here, we show that loss of function of either P0 or Mrt4 results in a deficit in 60S subunits, which is apparently due to impaired rRNA processing of 27S precursors. Mrt4, which shuttles between the nucleus and the cytoplasm, defines medium pre-60S particles. In contrast, P0 is absent from medium but present in late/cytoplasmic pre-60S complexes. The absence of Mrt4 notably increased the amount of P0 in nuclear Nop7-TAP complexes and causes P0 assembly to medium pre-60S particles. Upon P0 depletion, Mrt4 is relocated to the cytoplasm within aberrant 60S subunits. We conclude that Mrt4 controls the position and timing of P0 assembly. In turn, P0 is required for the release of Mrt4 and exchanges with this factor at the cytoplasm. Our results also suggest other P0 assembly alternatives.
Collapse
Affiliation(s)
- María Rodríguez-Mateos
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Cantoblanco E-28049 Madrid and Departamento de Genética, Universidad de Sevilla, E-41012 Sevilla, Spain
| | - Juan J. García-Gómez
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Cantoblanco E-28049 Madrid and Departamento de Genética, Universidad de Sevilla, E-41012 Sevilla, Spain
| | - Rosario Francisco-Velilla
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Cantoblanco E-28049 Madrid and Departamento de Genética, Universidad de Sevilla, E-41012 Sevilla, Spain
| | - Miguel Remacha
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Cantoblanco E-28049 Madrid and Departamento de Genética, Universidad de Sevilla, E-41012 Sevilla, Spain
| | - Jesús de la Cruz
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Cantoblanco E-28049 Madrid and Departamento de Genética, Universidad de Sevilla, E-41012 Sevilla, Spain
| | - Juan P. G. Ballesta
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Cantoblanco E-28049 Madrid and Departamento de Genética, Universidad de Sevilla, E-41012 Sevilla, Spain
| |
Collapse
|
40
|
Mechanochemical removal of ribosome biogenesis factors from nascent 60S ribosomal subunits. Cell 2009; 138:911-22. [PMID: 19737519 DOI: 10.1016/j.cell.2009.06.045] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Revised: 05/11/2009] [Accepted: 06/17/2009] [Indexed: 11/20/2022]
Abstract
The dynein-related AAA ATPase Rea1 is a preribosomal factor that triggers an unknown maturation step in 60S subunit biogenesis. Using electron microscopy, we show that Rea1's motor domain is docked to the pre-60S particle and its tail-like structure, harboring a metal ion-dependent adhesion site (MIDAS), protrudes from the preribosome. Typically, integrins utilize a MIDAS to bind extracellular ligands, an interaction that is strengthened under applied tensile force. Likewise, the Rea1 MIDAS binds the preribosomal factor Rsa4, which is located on the pre-60S subunit at a site that is contacted by the flexible Rea1 tail. The MIDAS-Rsa4 interaction is essential for ATP-dependent dissociation of a group of non-ribosomal factors from the pre-60S particle. Thus, Rea1 aligns with its interacting partners on the preribosome to effect a necessary step on the path to the export-competent 60S subunit.
Collapse
|
41
|
Abstract
More than 170 assembly factors aid the construction and maturation of yeast ribosomes. After these factors' functions are completed, they must be released from preribosomes. In this issue, Ulbrich et al. (2009) describe a mechanochemical process through which the AAA ATPase Rea1 induces release of an assembly protein complex from preribosomes.
Collapse
Affiliation(s)
- Jason Talkish
- Department of Biological Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | | |
Collapse
|
42
|
Mrd1p is required for release of base-paired U3 snoRNA within the preribosomal complex. Mol Cell Biol 2009; 29:5763-74. [PMID: 19704003 DOI: 10.1128/mcb.00428-09] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In eukaryotes, ribosomes are made from precursor rRNA (pre-rRNA) and ribosomal proteins in a maturation process that requires a large number of snoRNPs and processing factors. A fundamental problem is how the coordinated and productive folding of the pre-rRNA and assembly of successive pre-rRNA-protein complexes is achieved cotranscriptionally. The conserved protein Mrd1p, which contains five RNA binding domains (RBDs), is essential for processing events leading to small ribosomal subunit synthesis. We show that full function of Mrd1p requires all five RBDs and that the RBDs are functionally distinct and needed during different steps in processing. Mrd1p mutations trap U3 snoRNA in pre-rRNP complexes both in base-paired and non-base-paired interactions. A single essential RBD, RBD5, is involved in both types of interactions, but its conserved RNP1 motif is not needed for releasing the base-paired interactions. RBD5 is also required for the late pre-rRNP compaction preceding A(2) cleavage. Our results suggest that Mrd1p modulates successive conformational rearrangements within the pre-rRNP that influence snoRNA-pre-rRNA contacts and couple U3 snoRNA-pre-rRNA remodeling and late steps in pre-rRNP compaction that are essential for cleavage at A(0) to A(2). Mrd1p therefore coordinates key events in biosynthesis of small ribosome subunits.
Collapse
|
43
|
Staley JP, Woolford JL. Assembly of ribosomes and spliceosomes: complex ribonucleoprotein machines. Curr Opin Cell Biol 2009; 21:109-18. [PMID: 19167202 PMCID: PMC2698946 DOI: 10.1016/j.ceb.2009.01.003] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 12/22/2008] [Accepted: 01/06/2009] [Indexed: 12/19/2022]
Abstract
Ribosomes and spliceosomes are ribonucleoprotein nanomachines that catalyze translation of mRNA to synthesize proteins and splicing of introns from pre-mRNAs, respectively. Assembly of ribosomes involves more than 300 proteins and RNAs, and that of spliceosomes over 100 proteins and RNAs. Construction of these enormous ribonucleoprotein particles (RNPs) is a dynamic process, in which the nascent RNPs undergo numerous ordered rearrangements of RNA-RNA, RNA-protein, and protein-protein interactions. Here we outline similar principles that have emerged from studies of ribosome and spliceosome assembly. Constituents of both RNPs form subassembly complexes, which can simplify the task of assembly and segregate functions of assembly factors. Reorganization of RNP topology, and proofreading of proper assembly, are catalyzed by protein- or RNA-dependent ATPases or GTPases. Dynamics of intermolecular interactions may be facilitated or regulated by cycles of post-translational modifications. Despite this repertoire of tools, mistakes occur in RNP assembly or in processing of RNA substrates. Quality control mechanisms recognize and turnover misassembled RNPs and reject improper substrates.
Collapse
Affiliation(s)
- Jonathan P Staley
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago IL 60637,
| | - John L Woolford
- Department of Biological Sciences, Center for Nucleic Acids Science and Technology, Carnegie Mellon University, Pittsburgh PA 15213, , Phone: (412) 268-3193, FAX: (412) 268-7129
| |
Collapse
|
44
|
Kressler D, Roser D, Pertschy B, Hurt E. The AAA ATPase Rix7 powers progression of ribosome biogenesis by stripping Nsa1 from pre-60S particles. ACTA ACUST UNITED AC 2008; 181:935-44. [PMID: 18559667 PMCID: PMC2426938 DOI: 10.1083/jcb.200801181] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Ribosome biogenesis takes place successively in the nucleolar, nucleoplasmic, and cytoplasmic compartments. Numerous nonribosomal factors transiently associate with the nascent ribosomes, but the mechanisms driving ribosome formation are mostly unknown. Here, we show that an energy-consuming enzyme, the AAA-type (ATPases associated with various cellular activities) ATPase Rix7, restructures a novel pre-60S particle at the transition from the nucleolus to nucleoplasm. Rix7 interacts genetically with Nsa1 and is targeted to the Nsa1-defined preribosomal particle. In vivo, Nsa1 cannot dissociate from pre-60S particles in rix7 mutants, causing nucleolar Nsa1 to escape to the cytoplasm, where it remains associated with aberrant 60S subunits. Altogether, our data suggest that Rix7 is required for the release of Nsa1 from a discrete preribosomal particle, thereby triggering the progression of 60S ribosome biogenesis.
Collapse
Affiliation(s)
- Dieter Kressler
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany
| | | | | | | |
Collapse
|
45
|
Bachellier-Bassi S, Gadal O, Bourout G, Nehrbass U. Cell cycle-dependent kinetochore localization of condensin complex in Saccharomyces cerevisiae. J Struct Biol 2008; 162:248-59. [PMID: 18296067 DOI: 10.1016/j.jsb.2008.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 12/20/2007] [Accepted: 01/04/2008] [Indexed: 01/01/2023]
Abstract
In budding yeast mitosis is endonuclear and associated with a very limited condensation of the chromosomes. Despite this partial chromosomal condensation, condensin is conserved and essential for the Saccharomyces cerevisiae mitotic cycle. Here, we investigate the localization of condensin during the mitotic cycle. In addition to a constitutive association with rDNA, we have discovered that condensin is localized to the kinetochore in a cell cycle-dependent manner. Shortly after duplication of the spindle pole body, the yeast equivalent of the centrosome, we observed a local enrichment of condensin colocalizing with kinetochore components. This specific association is consistent with mutant phenotypes of chromosome loss and defective sister chromatid separation at anaphase. During a short period of the cell cycle, we observed, at the single cell level, a spatial proximity of condensin and a cohesin rosette, without colocalization. Furthermore, using a genetic screen we demonstrated that condensin localization at kinetochores is specifically impaired in a mutant for ulp2/smt4, an abundant SUMO protease. In conclusion, during chromosome segregation, we established a SUMO-dependent cell cycle-specific condensin concentration colocalizing with kinetochores.
Collapse
Affiliation(s)
- Sophie Bachellier-Bassi
- Unité de Biologie Cellulaire du Noyau, CNRS URA 2582, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris cedex 15, France.
| | | | | | | |
Collapse
|
46
|
Bradatsch B, Katahira J, Kowalinski E, Bange G, Yao W, Sekimoto T, Baumgärtel V, Boese G, Bassler J, Wild K, Peters R, Yoneda Y, Sinning I, Hurt E. Arx1 functions as an unorthodox nuclear export receptor for the 60S preribosomal subunit. Mol Cell 2007; 27:767-79. [PMID: 17803941 DOI: 10.1016/j.molcel.2007.06.034] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Revised: 03/30/2007] [Accepted: 06/21/2007] [Indexed: 10/22/2022]
Abstract
Shuttling transport receptors carry cargo through nuclear pore complexes (NPCs) via transient interactions with Phe-Gly (FG)-rich nucleoporins. Here, we identify Arx1, a factor associated with a late 60S preribosomal particle in the nucleus, as an unconventional export receptor. Arx1 binds directly to FG nucleoporins and exhibits facilitated translocation through NPCs. Moreover, Arx1 functionally overlaps with the other 60S export receptors, Xpo1 and Mex67-Mtr2, and is genetically linked to nucleoporins. Unexpectedly, Arx1 is structurally unrelated to known shuttling transport receptors but homologous to methionine aminopeptidases (MetAPs), however, without enzymatic activity. Typically, the MetAP fold creates a central cavity that binds the methionine. In contrast, the predicted central cavity of Arx1 is involved in the interaction with FG repeat nucleoporins and 60S subunit export. Thus, an ancient enzyme fold has been adopted by Arx1 to function as a nuclear export receptor.
Collapse
Affiliation(s)
- Bettina Bradatsch
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Zhang J, Harnpicharnchai P, Jakovljevic J, Tang L, Guo Y, Oeffinger M, Rout MP, Hiley SL, Hughes T, Woolford JL. Assembly factors Rpf2 and Rrs1 recruit 5S rRNA and ribosomal proteins rpL5 and rpL11 into nascent ribosomes. Genes Dev 2007; 21:2580-92. [PMID: 17938242 PMCID: PMC2000323 DOI: 10.1101/gad.1569307] [Citation(s) in RCA: 162] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Accepted: 08/21/2007] [Indexed: 12/31/2022]
Abstract
More than 170 proteins are necessary for assembly of ribosomes in eukaryotes. However, cofactors that function with each of these proteins, substrates on which they act, and the precise functions of assembly factors--e.g., recruiting other molecules into preribosomes or triggering structural rearrangements of pre-rRNPs--remain mostly unknown. Here we investigated the recruitment of two ribosomal proteins and 5S ribosomal RNA (rRNA) into nascent ribosomes. We identified a ribonucleoprotein neighborhood in preribosomes that contains two yeast ribosome assembly factors, Rpf2 and Rrs1, two ribosomal proteins, rpL5 and rpL11, and 5S rRNA. Interactions between each of these four proteins have been confirmed by binding assays in vitro. These molecules assemble into 90S preribosomal particles containing 35S rRNA precursor (pre-rRNA). Rpf2 and Rrs1 are required for recruiting rpL5, rpL11, and 5S rRNA into preribosomes. In the absence of association of these molecules with pre-rRNPs, processing of 27SB pre-rRNA is blocked. Consequently, the abortive 66S pre-rRNPs are prematurely released from the nucleolus to the nucleoplasm, and cannot be exported to the cytoplasm.
Collapse
MESH Headings
- Active Transport, Cell Nucleus
- GTP Phosphohydrolases
- Genes, Fungal
- Macromolecular Substances
- Models, Biological
- Models, Molecular
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- RNA Processing, Post-Transcriptional
- RNA, Fungal/chemistry
- RNA, Fungal/genetics
- RNA, Fungal/metabolism
- RNA, Ribosomal, 5S/chemistry
- RNA, Ribosomal, 5S/genetics
- RNA, Ribosomal, 5S/metabolism
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- Ribosomal Protein L10
- Ribosomal Proteins/chemistry
- Ribosomal Proteins/genetics
- Ribosomal Proteins/metabolism
- Ribosomes/genetics
- Ribosomes/metabolism
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
- Saccharomyces cerevisiae Proteins/genetics
- Saccharomyces cerevisiae Proteins/metabolism
Collapse
Affiliation(s)
- Jingyu Zhang
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Piyanun Harnpicharnchai
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Jelena Jakovljevic
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Lan Tang
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Yurong Guo
- Division of Pulmonary and Critical Care Medicine, School of Medicine, John Hopkins University, Baltimore, Maryland 21224, USA
| | | | | | - Shawna L. Hiley
- Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Timothy Hughes
- Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - John L. Woolford
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| |
Collapse
|
48
|
Pertschy B, Saveanu C, Zisser G, Lebreton A, Tengg M, Jacquier A, Liebminger E, Nobis B, Kappel L, van der Klei I, Högenauer G, Fromont-Racine M, Bergler H. Cytoplasmic recycling of 60S preribosomal factors depends on the AAA protein Drg1. Mol Cell Biol 2007; 27:6581-92. [PMID: 17646390 PMCID: PMC2099225 DOI: 10.1128/mcb.00668-07] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Allelic forms of DRG1/AFG2 confer resistance to the drug diazaborine, an inhibitor of ribosome biogenesis in Saccharomyces cerevisiae. Our results show that the AAA-ATPase Drg1 is essential for 60S maturation and associates with 60S precursor particles in the cytoplasm. Functional inactivation of Drg1 leads to an increased cytoplasmic localization of shuttling pre-60S maturation factors like Rlp24, Arx1, and Tif6. Surprisingly, Nog1, a nuclear pre-60S factor, was also relocalized to the cytoplasm under these conditions, suggesting that it is a previously unsuspected shuttling preribosomal factor that is exported with the precursor particles and very rapidly reimported. Proteins that became cytoplasmic under drg1 mutant conditions were blocked on pre-60S particles at a step that precedes the association of Rei1, a later-acting preribosomal factor. A similar cytoplasmic accumulation of Nog1 and Rlp24 in pre-60S-bound form could be seen after overexpression of a dominant-negative Drg1 variant mutated in the D2 ATPase domain. We conclude that the ATPase activity of Drg1 is required for the release of shuttling proteins from the pre-60S particles shortly after their nuclear export. This early cytoplasmic release reaction defines a novel step in eukaryotic ribosome maturation.
Collapse
Affiliation(s)
- Brigitte Pertschy
- Institut für Molekulare Biowissenschaften. Karl-Franzens Universität Graz, Universitätsplatz 2, A-8010, Graz, Austria
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Chantha SC, Matton DP. Underexpression of the plant NOTCHLESS gene, encoding a WD-repeat protein, causes pleitropic phenotype during plant development. PLANTA 2007; 225:1107-20. [PMID: 17086402 DOI: 10.1007/s00425-006-0420-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Accepted: 09/29/2006] [Indexed: 05/12/2023]
Abstract
WD-repeat proteins are involved in a breadth of cellular processes. While the WD-repeat protein encoding gene NOTCHLESS has been involved in the regulation of the Notch signaling pathway in Drosophila, its yeast homolog Rsa4p was shown to participate in 60S ribosomal subunit biogenesis. The plant homolog ScNLE was previously characterized in Solanum chacoense (ScNLE) as being involved in seed development. However, expression data and reduced size of ScNLE underexpressing plants suggested in addition a role during shoot development. We here report the detailed phenotypic characterization of ScNLE underexpressing plants during shoot development. ScNLE was shown to be expressed in actively dividing cells of the shoot apex. Consistent with this, ScNLE underexpression caused pleiotropic defects such as a reduction in aerial organ size, a reduction in some organ numbers, delayed flowering, and an increase in stomatal index. Analysis of adaxial epidermal cells revealed that both cell number and cell size were reduced in mature leaves of ScNLE underexpressing lines. Two-hybrid screens with the Nle domain and the WD-repeat domain of ScNLE allowed the isolation of homologs of yeast MIDASIN and NSA2 genes, the products of which are involved in 60S ribosomal subunit biogenesis in yeast. A ScNLE-GFP chimeric protein was localized in both the cytoplasm and nucleus. These data altogether suggest that ScNLE likely plays a role in 60S ribosomal subunit biogenesis, which is essential for proper cellular growth and proliferation during plant development.
Collapse
Affiliation(s)
- Sier-Ching Chantha
- Département de Sciences Biologiques, Institut de Recherche en Biologie Végétale (IRBV), Université de Montréal, 4101 rue Sherbrooke Est, Montréal, QC, Canada H1X 2B2
| | | |
Collapse
|
50
|
Saveanu C, Rousselle JC, Lenormand P, Namane A, Jacquier A, Fromont-Racine M. The p21-activated protein kinase inhibitor Skb15 and its budding yeast homologue are 60S ribosome assembly factors. Mol Cell Biol 2007; 27:2897-909. [PMID: 17308036 PMCID: PMC1899936 DOI: 10.1128/mcb.00064-07] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ribosome biogenesis is driven by a large number of preribosomal factors that associate with and dissociate from the preribosomal particles along the maturation pathway. We have previously shown that budding yeast Mak11, whose homologues in other eukaryotes were described as modulating a p21-activated protein kinase function, accumulates in Rlp24-associated pre-60S complexes when their maturation is impeded in Saccharomyces cerevisiae. The functional inactivation of WD40 repeat protein Mak11 interfered with the 60S rRNA maturation, led to a cell cycle delay in G(1), and blocked green fluorescent protein-tagged Rpl25 in the nucleoli of yeast cells, indicating an early role of Mak11 in ribosome assembly. Surprisingly, Mak11 inactivation also led to a dramatic destabilization of Rlp24. The suppression of the thermosensitive phenotype of a mak11 mutant by RLP24 overexpression and a direct in vitro interaction between Rlp24 and Mak11 suggest that Mak11 acts as an Rlp24 cofactor during early steps of 60S ribosomal subunit assembly. Moreover, we found that Skb15, the Mak11 homologue in Schizosaccharomyces pombe, also associated with preribosomes and affected 60S biogenesis in fission yeast. It is thus likely that the previously observed phenotypes for MAK11 homologues in other eukaryotes are secondary to the main function of these proteins in ribosome formation.
Collapse
Affiliation(s)
- Cosmin Saveanu
- Génétique des Interactions Macromoléculaires, Institut Pasteur, 25 rue du docteur Roux, 75724 Paris Cedex 15, France
| | | | | | | | | | | |
Collapse
|