1
|
Wang D, Hou L, Ji Y, Xie J, Zhao J, Zhu N, Yang X, Zhou J, Cui Y, Guo J, Feng X, Liu J. Ubiquitination-dependent degradation of nucleolin mediated by porcine circovirus type 3 capsid protein. J Virol 2023; 97:e0089423. [PMID: 38032196 PMCID: PMC10734473 DOI: 10.1128/jvi.00894-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 09/27/2023] [Indexed: 12/01/2023] Open
Abstract
IMPORTANCE Porcine circovirus type 3 (PCV3) is an emerging pathogen that causes multisystem disease in pigs and poses a severe threat to the swine industry. However, the mechanisms of how PCV3 uses host proteins to regulate its own life cycle are not well understood. In this study, we found that PCV3 capsid protein interacts with nucleolin and degrades it. Degradation of nucleolin by the PCV3 capsid protein requires recruitment of the enzyme RNF34, which is transported to the nucleolus from the cytoplasm in the presence of the PCV3 capsid protein. Nucleolin also decreases PCV3 replication by promoting the release of interferon β. These findings clarify the mechanism by which nucleolin modulates PCV3 replication in cells, thereby facilitating to provide an important strategy for preventing and controlling PCV3 infection.
Collapse
Affiliation(s)
- Dedong Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Lei Hou
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Ying Ji
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Jiali Xie
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Jie Zhao
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Ning Zhu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Xiaoyu Yang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Jianwei Zhou
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Yongqiu Cui
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Jinshuo Guo
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Xufei Feng
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Jue Liu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| |
Collapse
|
2
|
Peggion C, Massimino ML, Pereira D, Granuzzo S, Righetto F, Bortolotto R, Agostini J, Sartori G, Bertoli A, Lopreiato R. Structural Integrity of Nucleolin Is Required to Suppress TDP-43-Mediated Cytotoxicity in Yeast and Human Cell Models. Int J Mol Sci 2023; 24:17466. [PMID: 38139294 PMCID: PMC10744044 DOI: 10.3390/ijms242417466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/28/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023] Open
Abstract
The Transactivating response (TAR) element DNA-binding of 43 kDa (TDP-43) is mainly implicated in the regulation of gene expression, playing multiple roles in RNA metabolism. Pathologically, it is implicated in amyotrophic lateral sclerosis and in a class of neurodegenerative diseases broadly going under the name of frontotemporal lobar degeneration (FTLD). A common hallmark of most forms of such diseases is the presence of TDP-43 insoluble inclusions in the cell cytosol. The molecular mechanisms of TDP-43-related cell toxicity are still unclear, and the contribution to cell damage from either loss of normal TDP-43 function or acquired toxic properties of protein aggregates is yet to be established. Here, we investigate the effects on cell viability of FTLD-related TDP-43 mutations in both yeast and mammalian cell models. Moreover, we focus on nucleolin (NCL) gene, recently identified as a genetic suppressor of TDP-43 toxicity, through a thorough structure/function characterization aimed at understanding the role of NCL domains in rescuing TDP-43-induced cytotoxicity. Using functional and biochemical assays, our data demonstrate that the N-terminus of NCL is necessary, but not sufficient, to exert its antagonizing effects on TDP-43, and further support the relevance of the DNA/RNA binding central region of the protein. Concurrently, data suggest the importance of the NCL nuclear localization for TDP-43 trafficking, possibly related to both TDP-43 physiology and toxicity.
Collapse
Affiliation(s)
- Caterina Peggion
- Department of Biology, University of Padova, 35131 Padova, Italy
| | | | - Daniel Pereira
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
- Department of Bioengineering, iBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal
| | - Sara Granuzzo
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
| | - Francesca Righetto
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
| | - Raissa Bortolotto
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
| | - Jessica Agostini
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
| | - Geppo Sartori
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
| | - Alessandro Bertoli
- Neuroscience Institute, Consiglio Nazionale Delle Ricerche, 35131 Padova, Italy
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
- Padova Neuroscience Center, University of Padova, 35131 Padova, Italy
| | - Raffaele Lopreiato
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
| |
Collapse
|
3
|
Custer SK, Gilson T, Astroski JW, Nanguneri SR, Iurillo AM, Androphy EJ. COPI coatomer subunit α-COP interacts with the RNA binding protein Nucleolin via a C-terminal dilysine motif. Hum Mol Genet 2023; 32:3263-3275. [PMID: 37658769 PMCID: PMC10656708 DOI: 10.1093/hmg/ddad140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 08/07/2023] [Accepted: 08/30/2023] [Indexed: 09/05/2023] Open
Abstract
The COPI coatomer subunit α-COP has been shown to co-precipitate mRNA in multiple settings, but it was unclear whether the interaction with mRNA was direct or mediated by interaction with an adapter protein. The COPI complex often interacts with proteins via C-terminal dilysine domains. A search for candidate RNA binding proteins with C-terminal dilysine motifs yielded Nucleolin, which terminates in a KKxKxx sequence. This protein was an especially intriguing candidate as it has been identified as an interacting partner for Survival Motor Neuron protein (SMN). Loss of SMN causes the neurodegenerative disease Spinal Muscular Atrophy. We have previously shown that SMN and α-COP interact and co-migrate in axons, and that overexpression of α-COP reduced phenotypic severity in cell culture and animal models of SMA. We show here that in an mRNA independent manner, endogenous Nucleolin co-precipitates endogenous α-COP and ε-COP but not β-COP which may reflect an interaction with the so-called B-subcomplex rather a complete COPI heptamer. The ability of Nucleolin to bind to α-COP requires the presence of the C-terminal KKxKxx domain of Nucleolin. Furthermore, we have generated a point mutant in the WD40 domain of α-COP which eliminates its ability to co-precipitate Nucleolin but does not interfere with precipitation of partners mediated by non-KKxKxx motifs such as the kainate receptor subunit 2. We propose that via interaction between the C-terminal dilysine motif of Nucleolin and the WD40 domain of α-COP, Nucleolin acts an adaptor to allow α-COP to interact with a population of mRNA.
Collapse
Affiliation(s)
- Sara K Custer
- Dermatology, Indiana University School of Medicine, 545 Barnhill Drive, Emerson Hall 139, Indianapolis, IN 46202, United States
| | - Timra Gilson
- Dermatology, Indiana University School of Medicine, 545 Barnhill Drive, Emerson Hall 139, Indianapolis, IN 46202, United States
| | - Jacob W Astroski
- Dermatology, Indiana University School of Medicine, 545 Barnhill Drive, Emerson Hall 139, Indianapolis, IN 46202, United States
| | - Siddarth R Nanguneri
- Dermatology, Indiana University School of Medicine, 545 Barnhill Drive, Emerson Hall 139, Indianapolis, IN 46202, United States
| | - Alyssa M Iurillo
- Indiana University School of Medicine, 340 West 10 St, Indianapolis, IN 46202, United States
| | - Elliot J Androphy
- Dermatology, Indiana University School of Medicine, 545 Barnhill Drive, Emerson Hall 139, Indianapolis, IN 46202, United States
| |
Collapse
|
4
|
Jeilani M, Billington K, Sunter JD, Dean S, Wheeler RJ. Nucleolar targeting in an early-branching eukaryote suggests a general mechanism for ribosome protein sorting. J Cell Sci 2022; 135:jcs259701. [PMID: 36052646 PMCID: PMC9659390 DOI: 10.1242/jcs.259701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 08/24/2022] [Indexed: 11/20/2022] Open
Abstract
The compartmentalised eukaryotic cell demands accurate targeting of proteins to the organelles in which they function, whether membrane-bound (like the nucleus) or non-membrane-bound (like the nucleolus). Nucleolar targeting relies on positively charged localisation signals and has received rejuvenated interest since the widespread recognition of liquid-liquid phase separation (LLPS) as a mechanism contributing to nucleolus formation. Here, we exploit a new genome-wide analysis of protein localisation in the early-branching eukaryote Trypanosoma brucei to analyse general nucleolar protein properties. T. brucei nucleolar proteins have similar properties to those in common model eukaryotes, specifically basic amino acids. Using protein truncations and addition of candidate targeting sequences to proteins, we show both homopolymer runs and distributed basic amino acids give nucleolar partition, further aided by a nuclear localisation signal (NLS). These findings are consistent with phase separation models of nucleolar formation and physical protein properties being a major contributing mechanism for eukaryotic nucleolar targeting, conserved from the last eukaryotic common ancestor. Importantly, cytoplasmic ribosome proteins, unlike mitochondrial ribosome proteins, have more basic residues - pointing to adaptation of physicochemical properties to assist segregation.
Collapse
Affiliation(s)
- Milad Jeilani
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Karen Billington
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - Jack Daniel Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - Samuel Dean
- Warwick Medical School, Warwick University, Warwick CV4 7AL, UK
| | - Richard John Wheeler
- Peter Medawar Building for Pathogen Research, Nuffield Department of Medicine, University of Oxford, Oxford OX1 3SY, UK
| |
Collapse
|
5
|
Muñoz-Díaz E, Sáez-Vásquez J. Nuclear dynamics: Formation of bodies and trafficking in plant nuclei. FRONTIERS IN PLANT SCIENCE 2022; 13:984163. [PMID: 36082296 PMCID: PMC9445803 DOI: 10.3389/fpls.2022.984163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/04/2022] [Indexed: 06/01/2023]
Abstract
The existence of the nucleus distinguishes prokaryotes and eukaryotes. Apart from containing most of the genetic material, the nucleus possesses several nuclear bodies composed of protein and RNA molecules. The nucleus is separated from the cytoplasm by a double membrane, regulating the trafficking of molecules in- and outwards. Here, we investigate the composition and function of the different plant nuclear bodies and molecular clues involved in nuclear trafficking. The behavior of the nucleolus, Cajal bodies, dicing bodies, nuclear speckles, cyclophilin-containing bodies, photobodies and DNA damage foci is analyzed in response to different abiotic stresses. Furthermore, we research the literature to collect the different protein localization signals that rule nucleocytoplasmic trafficking. These signals include the different types of nuclear localization signals (NLSs) for nuclear import, and the nuclear export signals (NESs) for nuclear export. In contrast to these unidirectional-movement signals, the existence of nucleocytoplasmic shuttling signals (NSSs) allows bidirectional movement through the nuclear envelope. Likewise, nucleolar signals are also described, which mainly include the nucleolar localization signals (NoLSs) controlling nucleolar import. In contrast, few examples of nucleolar export signals, called nucleoplasmic localization signals (NpLSs) or nucleolar export signals (NoESs), have been reported. The existence of consensus sequences for these localization signals led to the generation of prediction tools, allowing the detection of these signals from an amino acid sequence. Additionally, the effect of high temperatures as well as different post-translational modifications in nuclear and nucleolar import and export is discussed.
Collapse
Affiliation(s)
- Eduardo Muñoz-Díaz
- Centre National de la Recherche Scientifique (CNRS), Laboratoire Génome et Développement des Plantes, UMR 5096, Perpignan, France
- Univ. Perpignan Via Domitia, Laboratoire Génome et Développement des Plantes, UMR 5096, Perpignan, France
| | - Julio Sáez-Vásquez
- Centre National de la Recherche Scientifique (CNRS), Laboratoire Génome et Développement des Plantes, UMR 5096, Perpignan, France
- Univ. Perpignan Via Domitia, Laboratoire Génome et Développement des Plantes, UMR 5096, Perpignan, France
| |
Collapse
|
6
|
Tonello F, Massimino ML, Peggion C. Nucleolin: a cell portal for viruses, bacteria, and toxins. Cell Mol Life Sci 2022; 79:271. [PMID: 35503380 PMCID: PMC9064852 DOI: 10.1007/s00018-022-04300-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 04/08/2022] [Accepted: 04/10/2022] [Indexed: 12/18/2022]
Abstract
The main localization of nucleolin is the nucleolus, but this protein is present in multiple subcellular sites, and it is unconventionally secreted. On the cell surface, nucleolin acts as a receptor for various viruses, some bacteria, and some toxins. Aim of this review is to discuss the characteristics that make nucleolin able to act as receptor or co-receptor of so many and different pathogens. The important features that emerge are its multivalence, and its role as a bridge between the cell surface and the nucleus. Multiple domains, short linear motifs and post-translational modifications confer and modulate nucleolin ability to interact with nucleic acids, with proteins, but also with carbohydrates and lipids. This modular multivalence allows nucleolin to participate in different types of biomolecular condensates and to move to various subcellular locations, where it can act as a kind of molecular glue. It moves from the nucleus to the cell surface and can accompany particles in the reverse direction, from the cell surface into the nucleus, which is the destination of several pathogens to manipulate the cell in their favour.
Collapse
Affiliation(s)
- Fiorella Tonello
- CNR of Italy, Neuroscience Institute, viale G. Colombo 3, 35131, Padua, Italy.
| | | | - Caterina Peggion
- Department of Biomedical Sciences, University of Padua, Via Ugo Bassi, 58/B, 35131, Padua, Italy
| |
Collapse
|
7
|
Kirman DC, Renganathan B, Chui WK, Chen MW, Kaya NA, Ge R. Cell surface nucleolin is a novel ADAMTS5 receptor mediating endothelial cell apoptosis. Cell Death Dis 2022; 13:172. [PMID: 35197459 PMCID: PMC8866485 DOI: 10.1038/s41419-022-04618-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 12/17/2021] [Accepted: 01/19/2022] [Indexed: 12/12/2022]
Abstract
A Disintegrin and Metalloproteinase with ThromboSpondin motif (ADAMTS) 5 functions as an anti-angiogenic and anti-cancer protein independent of its metalloproteinase activity. Both full-length ADAMTS5 and TS5-p45, the autocatalytically cleaved C-terminal 45 kDa truncate of ADAMTS5, inhibits angiogenesis, and induces endothelial cell (EC) apoptosis. However, how ADAMTS5 triggers EC apoptosis remains unclear. This work shows that caspase-8 (Cas-8) and caspase-9 (Cas-9) are involved in TS5-p45-induced EC apoptosis. We identify cell surface nucleolin (NCL) as a novel high-affinity receptor for TS5-p45 in ECs, mediating TS5-p45's cell surface binding and pro-apoptotic function. We show that the central RNA-binding domain (RBD) of NCL is essential and sufficient for its binding to TS5-p45. Upon interacting with EC surface NCL, TS5-p45 is internalized through clathrin- and caveolin-dependent endocytosis and trafficked to the nucleus via late endosomes (LEs). We demonstrate that the nuclear trafficking of TS5-p45 is important for its pro-apoptotic activity as disruption of LE membrane integrity with an endosomolytic peptide suppressed both nuclear trafficking and pro-apoptotic activity of TS5-p45. Through cell surface biotinylation, we revealed that cell surface NCL shuttles extracellular TS5-p45 to the nucleus to mediate apoptosis. Furthermore, blocking the importin α1/ß1 receptor hindered the nuclear trafficking of TS5-p45, suggesting the involvement of the nuclear importing machinery for this nuclear translocation. RNA-seq identified many apoptosis-related genes that are differentially expressed at least two-fold in TS5-p45-treated ECs, with 10 of them qRT-PCR-validated and at least 5 of these genes potentially contributing to TS5-p45-NCL-induced apoptosis. Altogether, our work identifies NCL as a novel cell surface receptor for ADAMTS5 and demonstrates the critical role of NCL-mediated internalization and nuclear trafficking for ADAMTS5-induced EC apoptosis. These findings reveal novel mechanistic insights of the secreted metalloproteinase ADAMTS5 in angiogenesis inhibition.
Collapse
Affiliation(s)
- Dogan Can Kirman
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
| | - Bhuvanasundar Renganathan
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
| | - Wai Kit Chui
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
| | - Ming Wei Chen
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Neslihan Arife Kaya
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, 138672, Singapore
| | - Ruowen Ge
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore.
| |
Collapse
|
8
|
Cote JL, Vander PB, Ellis M, Cline JM, Svezhova N, Doche ME, Maures TJ, Choudhury TA, Kong S, Klaft OGJ, Joe RM, Argetsinger LS, Carter-Su C. The nucleolar δ isoform of adapter protein SH2B1 enhances morphological complexity and function of cultured neurons. J Cell Sci 2022; 135:jcs259179. [PMID: 35019135 PMCID: PMC8918807 DOI: 10.1242/jcs.259179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 12/22/2021] [Indexed: 11/20/2022] Open
Abstract
The adapter protein SH2B1 is recruited to neurotrophin receptors, including TrkB (also known as NTRK2), the receptor for brain-derived neurotrophic factor (BDNF). Herein, we demonstrate that the four alternatively spliced isoforms of SH2B1 (SH2B1α-SH2B1δ) are important determinants of neuronal architecture and neurotrophin-induced gene expression. Primary hippocampal neurons from Sh2b1-/- [knockout (KO)] mice exhibit decreased neurite complexity and length, and BDNF-induced expression of the synapse-related immediate early genes Egr1 and Arc. Reintroduction of each SH2B1 isoform into KO neurons increases neurite complexity; the brain-specific δ isoform also increases total neurite length. Human obesity-associated variants, when expressed in SH2B1δ, alter neurite complexity, suggesting that a decrease or increase in neurite branching may have deleterious effects that contribute to the severe childhood obesity and neurobehavioral abnormalities associated with these variants. Surprisingly, in contrast to SH2B1α, SH2B1β and SH2B1γ, which localize primarily in the cytoplasm and plasma membrane, SH2B1δ resides primarily in nucleoli. Some SH2B1δ is also present in the plasma membrane and nucleus. Nucleolar localization, driven by two highly basic regions unique to SH2B1δ, is required for SH2B1δ to maximally increase neurite complexity and BDNF-induced expression of Egr1, Arc and FosL1.
Collapse
Affiliation(s)
- Jessica L. Cote
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Paul B. Vander
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Michael Ellis
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Joel M. Cline
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Nadezhda Svezhova
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Michael E. Doche
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Travis J. Maures
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Tahrim A. Choudhury
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Seongbae Kong
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Olivia G. J. Klaft
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Ray M. Joe
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Lawrence S. Argetsinger
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Christin Carter-Su
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| |
Collapse
|
9
|
Hao K, Chen Y, Yan X, Zhu X. Cilia locally synthesize proteins to sustain their ultrastructure and functions. Nat Commun 2021; 12:6971. [PMID: 34848703 PMCID: PMC8632896 DOI: 10.1038/s41467-021-27298-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 11/09/2021] [Indexed: 12/26/2022] Open
Abstract
Cilia are microtubule-based hair-like organelles propelling locomotion and extracellular liquid flow or sensing environmental stimuli. As cilia are diffusion barrier-gated subcellular compartments, their protein components are thought to come from the cell body through intraflagellar transport or diffusion. Here we show that cilia locally synthesize proteins to maintain their structure and functions. Multicilia of mouse ependymal cells are abundant in ribosomal proteins, translation initiation factors, and RNA, including 18 S rRNA and tubulin mRNA. The cilia actively generate nascent peptides, including those of tubulin. mRNA-binding protein Fmrp localizes in ciliary central lumen and appears to function in mRNA delivery into the cilia. Its depletion by RNAi impairs ciliary local translation and induces multicilia degeneration. Expression of exogenous Fmrp, but not an isoform tethered to mitochondria, rescues the degeneration defects. Therefore, local translation defects in cilia might contribute to the pathology of ciliopathies and other diseases such as Fragile X syndrome.
Collapse
Affiliation(s)
- Kai Hao
- grid.507739.f0000 0001 0061 254XState Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, 320 Yueyang Road, 200031 Shanghai, China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Yawen Chen
- grid.507739.f0000 0001 0061 254XState Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, 320 Yueyang Road, 200031 Shanghai, China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Xiumin Yan
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Institute of Early Life Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, 200092, Shanghai, China.
| | - Xueliang Zhu
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, 320 Yueyang Road, 200031, Shanghai, China. .,University of Chinese Academy of Sciences, 100049, Beijing, China. .,School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 310024, Hangzhou, China.
| |
Collapse
|
10
|
Doron‐Mandel E, Koppel I, Abraham O, Rishal I, Smith TP, Buchanan CN, Sahoo PK, Kadlec J, Oses‐Prieto JA, Kawaguchi R, Alber S, Zahavi EE, Di Matteo P, Di Pizio A, Song D, Okladnikov N, Gordon D, Ben‐Dor S, Haffner‐Krausz R, Coppola G, Burlingame AL, Jungwirth P, Twiss JL, Fainzilber M. The glycine arginine-rich domain of the RNA-binding protein nucleolin regulates its subcellular localization. EMBO J 2021; 40:e107158. [PMID: 34515347 PMCID: PMC8521312 DOI: 10.15252/embj.2020107158] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 07/29/2021] [Accepted: 08/03/2021] [Indexed: 12/31/2022] Open
Abstract
Nucleolin is a multifunctional RNA Binding Protein (RBP) with diverse subcellular localizations, including the nucleolus in all eukaryotic cells, the plasma membrane in tumor cells, and the axon in neurons. Here we show that the glycine arginine rich (GAR) domain of nucleolin drives subcellular localization via protein-protein interactions with a kinesin light chain. In addition, GAR sequences mediate plasma membrane interactions of nucleolin. Both these modalities are in addition to the already reported involvement of the GAR domain in liquid-liquid phase separation in the nucleolus. Nucleolin transport to axons requires the GAR domain, and heterozygous GAR deletion mice reveal reduced axonal localization of nucleolin cargo mRNAs and enhanced sensory neuron growth. Thus, the GAR domain governs axonal transport of a growth controlling RNA-RBP complex in neurons, and is a versatile localization determinant for different subcellular compartments. Localization determination by GAR domains may explain why GAR mutants in diverse RBPs are associated with neurodegenerative disease.
Collapse
Affiliation(s)
- Ella Doron‐Mandel
- Departments of Biomolecular Sciences and Molecular NeuroscienceWeizmann Institute of ScienceRehovotIsrael
- Present address:
Department of Biological SciencesColumbia UniversityNew YorkNYUSA
| | - Indrek Koppel
- Departments of Biomolecular Sciences and Molecular NeuroscienceWeizmann Institute of ScienceRehovotIsrael
- Present address:
Department of Chemistry and BiotechnologyTallinn University of TechnologyTallinnEstonia
| | - Ofri Abraham
- Departments of Biomolecular Sciences and Molecular NeuroscienceWeizmann Institute of ScienceRehovotIsrael
| | - Ida Rishal
- Departments of Biomolecular Sciences and Molecular NeuroscienceWeizmann Institute of ScienceRehovotIsrael
| | - Terika P Smith
- Department of Biological SciencesUniversity of South CarolinaColumbiaSCUSA
| | | | - Pabitra K Sahoo
- Department of Biological SciencesUniversity of South CarolinaColumbiaSCUSA
| | - Jan Kadlec
- Institute of Organic Chemistry and BiochemistryCzech Academy of SciencesPragueCzech Republic
| | - Juan A Oses‐Prieto
- Department of Pharmaceutical ChemistryUniversity of California San FranciscoSan FranciscoCAUSA
| | - Riki Kawaguchi
- Departments of Psychiatry and NeurologySemel Institute for Neuroscience and Human BehaviorUniversity of California Los AngelesLos AngelesCAUSA
| | - Stefanie Alber
- Departments of Biomolecular Sciences and Molecular NeuroscienceWeizmann Institute of ScienceRehovotIsrael
| | - Eitan Erez Zahavi
- Departments of Biomolecular Sciences and Molecular NeuroscienceWeizmann Institute of ScienceRehovotIsrael
| | - Pierluigi Di Matteo
- Departments of Biomolecular Sciences and Molecular NeuroscienceWeizmann Institute of ScienceRehovotIsrael
| | - Agostina Di Pizio
- Departments of Biomolecular Sciences and Molecular NeuroscienceWeizmann Institute of ScienceRehovotIsrael
| | - Didi‐Andreas Song
- Departments of Biomolecular Sciences and Molecular NeuroscienceWeizmann Institute of ScienceRehovotIsrael
| | - Nataliya Okladnikov
- Departments of Biomolecular Sciences and Molecular NeuroscienceWeizmann Institute of ScienceRehovotIsrael
| | - Dalia Gordon
- Departments of Biomolecular Sciences and Molecular NeuroscienceWeizmann Institute of ScienceRehovotIsrael
| | - Shifra Ben‐Dor
- Bioinformatics UnitLife Sciences Core FacilitiesWeizmann Institute of ScienceRehovotIsrael
| | | | - Giovanni Coppola
- Departments of Psychiatry and NeurologySemel Institute for Neuroscience and Human BehaviorUniversity of California Los AngelesLos AngelesCAUSA
| | - Alma L Burlingame
- Department of Pharmaceutical ChemistryUniversity of California San FranciscoSan FranciscoCAUSA
| | - Pavel Jungwirth
- Institute of Organic Chemistry and BiochemistryCzech Academy of SciencesPragueCzech Republic
| | - Jeffery L Twiss
- Department of Biological SciencesUniversity of South CarolinaColumbiaSCUSA
| | - Mike Fainzilber
- Departments of Biomolecular Sciences and Molecular NeuroscienceWeizmann Institute of ScienceRehovotIsrael
| |
Collapse
|
11
|
Yang L, Hu X, Cheng A, Wang M, Jia R, Yang Q, Wu Y, Chen S, Liu M, Zhu D, Ou X, Wen X, Mao S, Sun D, Zhang S, Zhao X, Huang J, Gao Q, Liu Y, Yu Y, Zhang L, Tian B, Pan L, Chen X. Two nuclear localization signals regulate intracellular localization of the duck enteritis virus UL13 protein. Poult Sci 2020; 100:26-38. [PMID: 33357689 PMCID: PMC7772677 DOI: 10.1016/j.psj.2020.09.069] [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: 07/04/2020] [Revised: 09/12/2020] [Accepted: 09/23/2020] [Indexed: 11/15/2022] Open
Abstract
Duck enteritis virus (DEV) multifunctional tegument protein UL13 is predicted to be a conserved herpesvirus protein kinase; however, little is known about its subcellular localization signal. In this study, through transfection of 2 predicted nuclear signals of DEV UL13 fused to enhanced green fluorescent protein, 2 bipartite nuclear localization signals (NLS) were identified. We found that ivermectin blocked the NLS-mediated nuclear import of DEV UL13, showing that the nuclear localization signal of DEV UL13 is a classical importin α- and β-dependent process. We constructed a DEV UL13 mutant strain in which the NLS of DEV UL13 was deleted to explore whether deletion of the NLS affects viral replication. Amino acids 4 to 7 and 90 to 96 were predicted to be NLSs, further proving that nuclear import occurs via a classical importin α- and β-dependent process. We also found that the NLS of pUL13 had no effect on DEV replication in cell culture. Our study enhances the understanding of DEV pUL13. Taken together, these results provide significant information regarding the biological function of pUL13 during DEV infection.
Collapse
Affiliation(s)
- Linjiang Yang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Xixia Hu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China.
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Renyong Jia
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Qiao Yang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Ying Wu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Shun Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Mafeng Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Dekang Zhu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Xumin Ou
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - XingJian Wen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Sai Mao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Di Sun
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Shaqiu Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Xinxin Zhao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Juan Huang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Qun Gao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Yunya Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Yanling Yu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Ling Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Bin Tian
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Leichang Pan
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| | - Xiaoyue Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China; Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, PR China
| |
Collapse
|
12
|
Identification and Characterization of the Nucleolar Localization Signal of Autographa californica Multiple Nucleopolyhedrovirus LEF5. J Virol 2020; 94:JVI.01891-19. [PMID: 31776271 DOI: 10.1128/jvi.01891-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 11/19/2019] [Indexed: 11/20/2022] Open
Abstract
Autographa californica multiple nucleopolyhedrovirus (AcMNPV) late expression factor 5 (LEF5) is highly conserved in all sequenced baculovirus genomes and plays an important role in production of infectious viral progeny. In this study, nucleolar localization of AcMNPV LEF5 was characterized. Through transcriptome analysis, we identified two putative nucleolar proteins, Spodoptera frugiperda nucleostemin (SfNS) and fibrillarin (SfFBL), from Sf9 cells. Immunofluorescence analysis demonstrated that SfNS and SfFBL were localized to the nucleolus. AcMNPV infection resulted in reorganization of the nucleoli of infected cells. Colocalization of LEF5 and SfNS showed that AcMNPV LEF5 was localized to the nucleolus in Sf9 cells. Bioinformatic analysis revealed that basic amino acids of LEF5 are enriched at residues 184 to 213 and may contain a nucleolar localization signal (NoLS). Green fluorescent protein (GFP) fused to NoLS of AcMNPV LEF5 localized to the nucleoli of transfected cells. Multiple-point mutation analysis demonstrated that amino acid residues 197 to 204 are important for nucleolar localization of LEF5. To identify whether the NoLS in AcMNPV LEF5 is important for production of viral progeny, a lef5-null AcMNPV bacmid was constructed; several NoLS-mutated LEF5 proteins were reinserted into the lef5-null AcMNPV bacmid with a GFP reporter. The constructs containing point mutations at residues 185 to 189 or 197 to 204 in AcMNPV LEF5 resulted in reduction in production of infectious viral progeny and occlusion body yield in bacmid-transfected cells. Together, these data suggested that AcMNPV LEF5 contains an NoLS, which is important for nucleolar localization of LEF5, progeny production, and occlusion body production.IMPORTANCE Many viruses, including human and plant viruses, target nucleolar functions as part of their infection strategy. However, nucleolar localization for baculovirus proteins has not yet been characterized. In this study, two nucleolar proteins, SfNS and SfFBL, were identified in Sf9 cells. Our results showed that Autographa californica multiple nucleopolyhedrovirus (AcMNPV) infection resulted in redistribution of the nucleoli of infected cells. We demonstrated that AcMNPV late expression factor 5 (LEF5) could localize to the nucleolus and contains a nucleolar localization signal (NoLS), which is important for nucleolar localization of AcMNPV LEF5 and for production of viral progeny and yield of occlusion bodies.
Collapse
|
13
|
Gomez GN, Abrar F, Dodhia MP, Gonzalez FG, Nag A. SARS coronavirus protein nsp1 disrupts localization of Nup93 from the nuclear pore complex. Biochem Cell Biol 2019; 97:758-766. [PMID: 30943371 DOI: 10.1139/bcb-2018-0394] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023] Open
Abstract
Severe acute respiratory syndrome coronavirus nonstructural protein 1 (nsp1) is a key factor in virus-induced down-regulation of host gene expression. In infected cells, nsp1 engages in a multipronged mechanism to inhibit host gene expression by binding to the 40S ribosome to block the assembly of translationally competent ribosome, and then inducing endonucleolytic cleavage and the degradation of host mRNAs. Here, we report a previously undetected mechanism by which nsp1 exploits the nuclear pore complex and disrupts the nuclear-cytoplasmic transport of biomolecules. We identified members of the nuclear pore complex from the nsp1-associated protein assembly and found that the expression of nsp1 in HEK cells disrupts Nup93 localization around the nuclear envelope without triggering proteolytic degradation, while the nuclear lamina remains unperturbed. Consistent with its role in host shutoff, nsp1 alters the nuclear-cytoplasmic distribution of an RNA binding protein, nucleolin. Our results suggest that nsp1, alone, can regulate multiple steps of gene expression including nuclear-cytoplasmic transport.
Collapse
Affiliation(s)
- Garret N Gomez
- Furman University, 3300 Poinsett Highway, Greenville, SC 29613, USA
- Furman University, 3300 Poinsett Highway, Greenville, SC 29613, USA
| | - Fareeha Abrar
- Furman University, 3300 Poinsett Highway, Greenville, SC 29613, USA
- Furman University, 3300 Poinsett Highway, Greenville, SC 29613, USA
| | - Maya P Dodhia
- Furman University, 3300 Poinsett Highway, Greenville, SC 29613, USA
- Furman University, 3300 Poinsett Highway, Greenville, SC 29613, USA
| | - Fabiola G Gonzalez
- Furman University, 3300 Poinsett Highway, Greenville, SC 29613, USA
- Furman University, 3300 Poinsett Highway, Greenville, SC 29613, USA
| | - Anita Nag
- Furman University, 3300 Poinsett Highway, Greenville, SC 29613, USA
| |
Collapse
|
14
|
Baltanás FC, Berciano MT, Tapia O, Narcis JO, Lafarga V, Díaz D, Weruaga E, Santos E, Lafarga M. Nucleolin reorganization and nucleolar stress in Purkinje cells of mutant PCD mice. Neurobiol Dis 2019; 127:312-322. [PMID: 30905767 DOI: 10.1016/j.nbd.2019.03.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/25/2019] [Accepted: 03/20/2019] [Indexed: 01/12/2023] Open
Abstract
The Purkinje cell (PC) degeneration (pcd) mouse harbors a mutation in Agtpbp1 gene that encodes for the cytosolic carboxypeptidase, CCP1. The mutation causes degeneration and death of PCs during the postnatal life, resulting in clinical and pathological manifestation of cerebellar ataxia. Monogenic biallelic damaging variants in the Agtpbp1 gene cause infantile-onset neurodegeneration and cerebellar atrophy, linking loss of functional CCP1 with human neurodegeneration. Although CCP1 plays a key role in the regulation of tubulin stabilization, its loss of function in PCs leads to a severe nuclear phenotype with heterochromatinization and accumulation of DNA damage. Therefore, the pcd mice provides a useful neuronal model to investigate nuclear mechanisms involved in neurodegeneration, particularly the nucleolar stress. In this study, we demonstrated that the Agtpbp1 gene mutation induces a p53-dependent nucleolar stress response in PCs, which is characterized by nucleolar fragmentation, nucleoplasmic and cytoplasmic mislocalization of nucleolin, and dysfunction of both pre-rRNA processing and mRNA translation. RT-qPCR analysis revealed reduction of mature 18S rRNA, with a parallel increase of its intermediate 18S-5'-ETS precursor, that correlates with a reduced expression of Fbl mRNA, which encodes an essential factor for rRNA processing. Moreover, nucleolar alterations were accompanied by a reduction of PTEN mRNA and protein levels, which appears to be related to the chromosome instability and accumulation of DNA damage in degenerating PCs. Our results highlight the essential contribution of nucleolar stress to PC degeneration and also underscore the nucleoplasmic mislocalization of nucleolin as a potential indicator of neurodegenerative processes.
Collapse
Affiliation(s)
- Fernando C Baltanás
- Lab.1, CIC-IBMCC (Universidad de Salamanca-CSIC) and CIBERONC, Salamanca, Spain
| | - María T Berciano
- Department of Anat and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Santander, Spain
| | - Olga Tapia
- Department of Anat and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Santander, Spain
| | - Josep Oriol Narcis
- Department of Anat and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Santander, Spain
| | - Vanesa Lafarga
- Laboratory of Genomic Instability, "Centro Nacional de Investigaciones Oncológicas" (CNIO), Madrid, Spain
| | - David Díaz
- Laboratory of Neural Plasticity and Neurorepair, Institute for Neuroscience of Castilla y León, Universidad de Salamanca, Salamanca, Spain
| | - Eduardo Weruaga
- Laboratory of Neural Plasticity and Neurorepair, Institute for Neuroscience of Castilla y León, Universidad de Salamanca, Salamanca, Spain
| | - Eugenio Santos
- Lab.1, CIC-IBMCC (Universidad de Salamanca-CSIC) and CIBERONC, Salamanca, Spain
| | - Miguel Lafarga
- Department of Anat and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Santander, Spain.
| |
Collapse
|
15
|
Šašinková M, Holoubek A, Otevřelová P, Kuželová K, Brodská B. AML-associated mutation of nucleophosmin compromises its interaction with nucleolin. Int J Biochem Cell Biol 2018; 103:65-73. [PMID: 30130654 DOI: 10.1016/j.biocel.2018.08.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 08/15/2018] [Accepted: 08/16/2018] [Indexed: 11/17/2022]
Abstract
C-terminal mutations of the nucleolar protein nucleophosmin (NPM) are the most frequent genetic aberration detected in acute myeloid leukemia (AML) with normal karyotype. The mutations cause aberrant cytoplasmic localization of NPM and lead to loss of functions associated with NPM nucleolar localization, e.g. in ribosome biogenesis or DNA-damage repair. NPM has many interaction partners and some of them were proved to interact also with the mutated form (NPMmut) and due to this interaction thereby to be withdrawn from their site of action. We analyzed the impact of the mutation on NPM interaction with nucleolin (NCL) which is also prevalently localized into the nucleolus and cooperates with wild-type NPM (NPMwt) in many cellular processes. We revealed that the NCL-NPM complex formation is completely abolished by the mutation and that the presence/absence of the interaction is not affected by drugs causing genotoxic stress or differentiation. Deregulation resulting from changes of NCL/NPMwt ratio may contribute to leukemogenesis.
Collapse
Affiliation(s)
- Markéta Šašinková
- Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 20 Prague 2, Czech Republic
| | - Aleš Holoubek
- Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 20 Prague 2, Czech Republic
| | - Petra Otevřelová
- Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 20 Prague 2, Czech Republic
| | - Kateřina Kuželová
- Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 20 Prague 2, Czech Republic
| | - Barbora Brodská
- Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 20 Prague 2, Czech Republic.
| |
Collapse
|
16
|
Sen Gupta A, Joshi G, Pawar S, Sengupta K. Nucleolin modulates compartmentalization and dynamics of histone 2B-ECFP in the nucleolus. Nucleus 2018; 9:350-367. [PMID: 29943658 PMCID: PMC6165600 DOI: 10.1080/19491034.2018.1471936] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Eukaryotic cells have 2 to 3 discrete nucleoli required for ribosome synthesis. Nucleoli are phase separated nuclear sub-organelles. Here we examined the role of nuclear Lamins and nucleolar factors in modulating the compartmentalization and dynamics of histone 2B (H2B-ECFP) in the nucleolus. Live imaging and Fluorescence Recovery After Photobleaching (FRAP) of labelled H2B, showed that the depletion of Lamin B1, Fibrillarin (FBL) or Nucleostemin (GNL3), enhances H2B-ECFP mobility in the nucleolus. Furthermore, Nucleolin knockdown significantly decreases H2B-ECFP compartmentalization in the nucleolus, while H2B-ECFP residence and mobility in the nucleolus was prolonged upon Nucleolin overexpression. Co-expression of N-terminal and RNA binding domain (RBD) deletion mutants of Nucleolin or inhibiting 45S rRNA synthesis reduces the sequestration of H2B-ECFP in the nucleolus. Taken together, these studies reveal a crucial role of Nucleolin-rRNA complex in modulating the compartmentalization, stability and dynamics of H2B within the nucleolus.
Collapse
Affiliation(s)
- Ayantika Sen Gupta
- Biology, Indian Institute of Science Education and Research (IISER), Pune, India
| | - Gaurav Joshi
- Biology, Indian Institute of Science Education and Research (IISER), Pune, India
| | - Sumit Pawar
- Biology, Indian Institute of Science Education and Research (IISER), Pune, India
| | - Kundan Sengupta
- Biology, Indian Institute of Science Education and Research (IISER), Pune, India
| |
Collapse
|
17
|
Jia W, Yao Z, Zhao J, Guan Q, Gao L. New perspectives of physiological and pathological functions of nucleolin (NCL). Life Sci 2017; 186:1-10. [PMID: 28751161 DOI: 10.1016/j.lfs.2017.07.025] [Citation(s) in RCA: 145] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 07/21/2017] [Accepted: 07/23/2017] [Indexed: 12/13/2022]
Abstract
Nucleolin (NCL) is a multifunctional protein that mainly localized in the nucleolus, it is also found in the nucleoplasm, cytoplasm and cell membrane. The three main structural domains allow the interaction of NCL with different proteins and RNA sequences. Moreover, specific post-translational modifications and its shuttling property also contribute to its multifunctionality. NCL has been demonstrated to be involved in a variety of aspects such as ribosome biogenesis, chromatin organization and stability, DNA and RNA metabolism, cytokinesis, cell proliferation, angiogenesis, apoptosis regulation, stress response and microRNA processing. NCL has been increasingly implicated in several pathological processes, especially in tumorigenesis and viral infection, which makes NCL a potential target for the development of anti-tumor and anti-viral strategies. In this review, we present an overview on the structure, localizations and various functions of NCL, and further describe how the multiple functions of NCL are correlated to its multiple cellular distributions.
Collapse
Affiliation(s)
- Wenyu Jia
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong Province, PR China; Shandong Provincial Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong Province, PR China; Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong Province, PR China
| | - Zhenyu Yao
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong Province, PR China; Shandong Provincial Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong Province, PR China; Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong Province, PR China
| | - Jiajun Zhao
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong Province, PR China; Shandong Provincial Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong Province, PR China; Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong Province, PR China
| | - Qingbo Guan
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong Province, PR China; Shandong Provincial Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong Province, PR China; Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong Province, PR China
| | - Ling Gao
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong Province, PR China; Shandong Provincial Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong Province, PR China; Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong Province, PR China.
| |
Collapse
|
18
|
Howard K, Cherezova L, DeMaster LK, Rose TM. ORF73 LANA homologs of RRV and MneRV2 contain an extended RGG/RG-rich nuclear and nucleolar localization signal that interacts directly with importin β1 for non-classical nuclear import. Virology 2017; 511:152-164. [PMID: 28850829 DOI: 10.1016/j.virol.2017.08.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 08/10/2017] [Accepted: 08/22/2017] [Indexed: 01/26/2023]
Abstract
The latency-associated nuclear antigens (LANA) of KSHV and macaque RFHVMn, members of the RV1 rhadinovirus lineage, are closely related with conservation of complex nuclear localization signals (NLS) containing bipartite KR-rich motifs and RG-rich domains, which interact distinctly with importins α and ß1 for nuclear import via classical and non-classical pathways, respectively. RV1 LANAs are expressed in the nucleus of latently-infected cells where they inhibit replication and establish a dominant RV1 latency. Here we show that LANA homologs of macaque RRV and MneRV2 from the more distantly-related RV2 lineage, lack the KR-rich NLS, and instead have a large RG-rich NLS with multiple RG dipeptides and a conserved RGG motif. The RG-NLS interacts uniquely with importin β1, which mediates nuclear import and accumulation of RV2 LANA in the nucleolus. The alternative nuclear import and localization of RV2 LANA homologs may contribute to the dominant RV2 lytic replication phenotype.
Collapse
Affiliation(s)
- Kellie Howard
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Global Health, University of Washington, Seattle, WA, USA.
| | - Lidia Cherezova
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Global Health, University of Washington, Seattle, WA, USA
| | - Laura K DeMaster
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Global Health, University of Washington, Seattle, WA, USA.
| | - Timothy M Rose
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Pediatrics, University of Washington, Seattle, WA, USA.
| |
Collapse
|
19
|
Scott DD, Oeffinger M. Nucleolin and nucleophosmin: nucleolar proteins with multiple functions in DNA repair. Biochem Cell Biol 2016; 94:419-432. [PMID: 27673355 DOI: 10.1139/bcb-2016-0068] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The nucleolus represents a highly multifunctional intranuclear organelle in which, in addition to the canonical ribosome assembly, numerous processes such as transcription, DNA repair and replication, the cell cycle, and apoptosis are coordinated. The nucleolus is further a key hub in the sensing of cellular stress and undergoes major structural and compositional changes in response to cellular perturbations. Numerous nucleolar proteins have been identified that, upon sensing nucleolar stress, deploy additional, non-ribosomal roles in the regulation of varied cell processes including cell cycle arrest, arrest of DNA replication, induction of DNA repair, and apoptosis, among others. The highly abundant proteins nucleophosmin (NPM1) and nucleolin (NCL) are two such factors that transit to the nucleoplasm in response to stress, and participate directly in the repair of numerous different DNA damages. This review discusses the contributions made by NCL and (or) NPM1 to the different DNA repair pathways employed by mammalian cells to repair DNA insults, and examines the implications of such activities for the regulation, pathogenesis, and therapeutic targeting of NPM1 and NCL.
Collapse
Affiliation(s)
- Daniel D Scott
- a Laboratory of RNP Biochemistry, Institut de recherches cliniques de Montréal (IRCM), Montréal, QC H2W 1R7, Canada
- b Division of Experimental Medicine, Faculty of Medicine, McGill University, Montréal, QC H3A 2A3, Canada
| | - Marlene Oeffinger
- a Laboratory of RNP Biochemistry, Institut de recherches cliniques de Montréal (IRCM), Montréal, QC H2W 1R7, Canada
- b Division of Experimental Medicine, Faculty of Medicine, McGill University, Montréal, QC H3A 2A3, Canada
- c Département de biochimie et médecine moléculaire, Faculté de Médecine, Université de Montréal, QC H3T 1J4, Canada
| |
Collapse
|
20
|
Shubina MY, Musinova YR, Sheval EV. Nucleolar methyltransferase fibrillarin: Evolution of structure and functions. BIOCHEMISTRY (MOSCOW) 2016; 81:941-50. [DOI: 10.1134/s0006297916090030] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
21
|
Martin RM, Ter-Avetisyan G, Herce HD, Ludwig AK, Lättig-Tünnemann G, Cardoso MC. Principles of protein targeting to the nucleolus. Nucleus 2016; 6:314-25. [PMID: 26280391 PMCID: PMC4615656 DOI: 10.1080/19491034.2015.1079680] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The nucleolus is the hallmark of nuclear compartmentalization and has been shown to exert multiple roles in cellular metabolism besides its main function as the place of rRNA synthesis and assembly of ribosomes. Nucleolar proteins dynamically localize and accumulate in this nuclear compartment relative to the surrounding nucleoplasm. In this study, we have assessed the molecular requirements that are necessary and sufficient for the localization and accumulation of peptides and proteins inside the nucleoli of living cells. The data showed that positively charged peptide entities composed of arginines alone and with an isoelectric point at and above 12.6 are necessary and sufficient for mediating significant nucleolar accumulation. A threshold of 6 arginines is necessary for peptides to accumulate in nucleoli, but already 4 arginines are sufficient when fused within 15 amino acid residues of a nuclear localization signal of a protein. Using a pH sensitive dye, we found that the nucleolar compartment is particularly acidic when compared to the surrounding nucleoplasm and, hence, provides the ideal electrochemical environment to bind poly-arginine containing proteins. In fact, we found that oligo-arginine peptides and GFP fusions bind RNA in vitro. Consistent with RNA being the main binding partner for arginines in the nucleolus, we found that the same principles apply to cells from insects to man, indicating that this mechanism is highly conserved throughout evolution.
Collapse
Affiliation(s)
- Robert M Martin
- a Instituto de Medicina Molecular ; Faculdade de Medicina ; Universidade de Lisboa ; Lisboa , Portugal
| | | | | | | | | | | |
Collapse
|
22
|
Yan R, Hu X, Zhang W, Song L, Wang J, Yin Y, Chen S, Zhao S. The mouse radial spoke protein 3 is a nucleocytoplasmic shuttling protein that promotes neurogenesis. Histochem Cell Biol 2015; 144:309-19. [PMID: 26082196 DOI: 10.1007/s00418-015-1338-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2015] [Indexed: 12/27/2022]
Abstract
Radial spoke protein 3 (RSP3) was first identified in Chlamydomonas as a component of radial spoke, which is important for flagellar motility. The mammalian homolog of the Chlamydomonas RSP3 protein is found to be a mammalian protein kinase A-anchoring protein that binds ERK1/2. Here we show that mouse RSP3 is a nucleocytoplasmic shuttling protein. The full-length RSP3-EGFP fusion protein is mainly located in the cytoplasm of Chinese hamster ovary cells. However, by using deletion mutants of RSP3, we identified two nuclear localization signals and a nuclear export signal in RSP3. Moreover, using in utero electroporation, we found that overexpression of RSP3 in the developing cerebral cortex promotes neurogenesis. The layer II/III of the neocortex was much thicker in the RSP3-transfected region than that of the untransfected region in the neocortex. We also show that RSP3 is specifically located in the primary cilia of the radial glial cells, where it acts as a signaling mediator that regulates neurogenesis. Thus, our results suggest that RSP3 is a nucleocytoplasmic shuttling protein and plays an essential role in neurogenesis.
Collapse
Affiliation(s)
- Runchuan Yan
- College of Veterinary Medicine, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi, People's Republic of China
| | - Xinde Hu
- College of Veterinary Medicine, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi, People's Republic of China
| | - Wei Zhang
- College of Veterinary Medicine, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi, People's Republic of China
| | - Lingzhen Song
- College of Veterinary Medicine, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi, People's Republic of China
| | - Jiutao Wang
- College of Veterinary Medicine, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi, People's Republic of China
| | - Yupeng Yin
- College of Veterinary Medicine, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi, People's Republic of China
| | - Shulin Chen
- College of Veterinary Medicine, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi, People's Republic of China
| | - Shanting Zhao
- College of Veterinary Medicine, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi, People's Republic of China.
| |
Collapse
|
23
|
Berger CM, Gaume X, Bouvet P. The roles of nucleolin subcellular localization in cancer. Biochimie 2015; 113:78-85. [PMID: 25866190 DOI: 10.1016/j.biochi.2015.03.023] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 03/29/2015] [Indexed: 01/10/2023]
Abstract
Nucleolin (NCL) is one of the most abundant non ribosomal protein of the nucleolus where it plays a central role in polymerase I transcription. NCL is also found outside of the nucleolus, in the nucleoplasm, cytoplasm as well as on the cell membrane. It acts in all cell compartments to control cellular homeostasis and therefore each cellular pool of NCL can play a different role in cancer development. NCL overexpression and its increased localization at the cell membrane is a common feature of several tumor cells. In cancer cells, NCL overexpression influences cell survival, proliferation and invasion through its action on different cellular pathways. In this review, we describe how the multiple functions of NCL that are associated to its multiple cellular localization can participate to the development of cancer.
Collapse
Affiliation(s)
- Caroline Madeleine Berger
- Département de Biologie, Master Biosciences, ENS de Lyon, Lyon, France; Ecole Normale Supérieure de Lyon, Laboratoire Joliot-Curie, CNRS USR 3010, 46 allée d'Italie, 69364 Lyon Cedex 7, France
| | - Xavier Gaume
- Ecole Normale Supérieure de Lyon, Laboratoire Joliot-Curie, CNRS USR 3010, 46 allée d'Italie, 69364 Lyon Cedex 7, France
| | - Philippe Bouvet
- Ecole Normale Supérieure de Lyon, Laboratoire Joliot-Curie, CNRS USR 3010, 46 allée d'Italie, 69364 Lyon Cedex 7, France.
| |
Collapse
|
24
|
Kenney SP, Meng XJ. Identification and fine mapping of nuclear and nucleolar localization signals within the human ribosomal protein S17. PLoS One 2015; 10:e0124396. [PMID: 25853866 PMCID: PMC4390217 DOI: 10.1371/journal.pone.0124396] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 03/13/2015] [Indexed: 01/29/2023] Open
Abstract
Human ribosomal protein S17 (RPS17) is mutated in Diamond-Blackfan Anemia (DBA), a bone marrow disorder that fails to produce sufficient red blood cells leading to anemia. Recently, an RPS17 protein sequence was also found to be naturally inserted in the genome of hepatitis E virus (HEV) from patients chronically-infected by HEV. The role of RPS17 in HEV replication and pathogenesis remains unknown due to the lack of knowledge about how RPS17 functions at a molecular level. Understanding the biological function of RPS17 is critical for elucidating its role in virus infection and DBA disease processes. In this study we probed the subcellular distribution of normal and mutant RPS17 proteins in a human liver cell line (Huh7). RPS17 was primarily detected within the nucleus, and more specifically within the nucleoli. Using a transient expression system in which RPS17 or truncations were expressed as fusions with enhanced yellow fluorescent protein (eYFP), we were able to identify and map, for the first time, two separate nuclear localization signals (NLSs), one to the first 13 amino acids of the amino-terminus of RPS17 and the other within amino acids 30-60. Additionally, we mapped amino acid sequences required for nucleolar accumulation of RPS17 to amino acids 60-70. Amino acids 60-70 possess a di-RG motif that may be necessary for nucleolar retention of RPS17. The results from this study enhance our knowledge of RSP17 and will facilitate future mechanistic studies about the roles of RSP17 in hepatitis E and DBA disease processes.
Collapse
Affiliation(s)
- Scott P. Kenney
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, United States of America
| | - Xiang-Jin Meng
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, United States of America
- * E-mail:
| |
Collapse
|
25
|
Identification and characterization of nuclear and nucleolar localization signals in the adeno-associated virus serotype 2 assembly-activating protein. J Virol 2014; 89:3038-48. [PMID: 25552709 DOI: 10.1128/jvi.03125-14] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
UNLABELLED Assembly-activating protein (AAP) of adeno-associated virus serotype 2 (AAV2) is a nucleolar-localizing protein that plays a critical role in transporting the viral capsid VP3 protein to the nucleolus for assembly. Here, we identify and characterize AAV2 AAP (AAP2) nuclear (NLS) and nucleolar (NoLS) localization signals near the carboxy-terminal region of AAP2 (amino acid positions 144 to 184) (AAP2(144-184)). This region contains five basic-amino-acid-rich (BR) clusters, KSKRSRR (AAP2BR1), RRR (AAP2BR2), RFR (AAP2BR3), RSTSSR (AAP2BR4), and RRIK (AAP2BR5), from the amino terminus to the carboxy terminus. We created 30 AAP2BR mutants by arginine/lysine-to-alanine mutagenesis or deletion of AAP2BRs and 8 and 1 green fluorescent protein (GFP)-AAP2BR and β-galactosidase-AAP2BR fusion proteins, respectively, and analyzed their intracellular localization in HeLa cells by immunofluorescence microscopy. The results showed that AAP2(144-184) has redundant multipartite NLSs and that any combinations of 4 AAP2BRs, but not 3 or less, can constitute a functional NLS-NoLS; AAP2BR1 and AAP2BR2 play the most influential role for nuclear localization, but either one of the two AAP2BRs is dispensable if all 4 of the other AAP2BRs are present, resulting in 3 different, overlapping NLS motifs; and the NoLS is shared redundantly among the five AAP2BRs and functions in a context-dependent manner. AAP2BR mutations not only resulted in aberrant intracellular localization, but also attenuated AAP2 protein expression to various degrees, and both of these abnormalities have a significant negative impact on capsid production. Thus, this study reveals the organization of the intermingling NLSs and NoLSs in AAP2 and provides insights into their functional roles in capsid assembly. IMPORTANCE Adeno-associated virus (AAV) has become a popular and successful vector for in vivo gene therapy; however, its biology has yet to be fully understood. In this regard, the recent discovery of the assembly-activating protein (AAP), a nonstructural, nucleolar-localizing AAV protein essential for viral capsid assembly, has provided us a new opportunity to better understand the fundamental processes required for virion formation. Here, we identify clusters of basic amino acids in the carboxy terminus of AAP from AAV serotype 2 (AAV2) that act as nuclear and nucleolar localization signals. We also demonstrate their importance in maintaining AAP expression levels and efficient production of viral capsids. Insights into the functions of AAP can elucidate the requirements and process for AAV capsid assembly, which may lead to improved vector production for use in gene therapy. This study also contributes to the growing body of work on nuclear and nucleolar localization signals.
Collapse
|
26
|
Taha MS, Nouri K, Milroy LG, Moll JM, Herrmann C, Brunsveld L, Piekorz RP, Ahmadian MR. Subcellular fractionation and localization studies reveal a direct interaction of the fragile X mental retardation protein (FMRP) with nucleolin. PLoS One 2014; 9:e91465. [PMID: 24658146 PMCID: PMC3962360 DOI: 10.1371/journal.pone.0091465] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 02/11/2014] [Indexed: 12/31/2022] Open
Abstract
Fragile X mental Retardation Protein (FMRP) is a well-known regulator of local translation of its mRNA targets in neurons. However, despite its ubiquitous expression, the role of FMRP remains ill-defined in other cell types. In this study we investigated the subcellular distribution of FMRP and its protein complexes in HeLa cells using confocal imaging as well as detergent-free fractionation and size exclusion protocols. We found FMRP localized exclusively to solid compartments, including cytosolic heavy and light membranes, mitochondria, nuclear membrane and nucleoli. Interestingly, FMRP was associated with nucleolin in both a high molecular weight ribosomal and translation-associated complex (≥6 MDa) in the cytosol, and a low molecular weight complex (∼200 kDa) in the nucleoli. Consistently, we identified two functional nucleolar localization signals (NoLSs) in FMRP that are responsible for a strong nucleolar colocalization of the C-terminus of FMRP with nucleolin, and a direct interaction of the N-terminus of FMRP with the arginine-glycine-glycine (RGG) domain of nucleolin. Taken together, we propose a novel mechanism by which a transient nucleolar localization of FMRP underlies a strong nucleocytoplasmic translocation, most likely in a complex with nucleolin and possibly ribosomes, in order to regulate translation of its target mRNAs.
Collapse
Affiliation(s)
- Mohamed S. Taha
- Institute of Biochemistry and Molecular Biology II, Medical Faculty of the Heinrich-Heine-University, Düsseldorf, Germany
| | - Kazem Nouri
- Institute of Biochemistry and Molecular Biology II, Medical Faculty of the Heinrich-Heine-University, Düsseldorf, Germany
| | - Lech G. Milroy
- Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering, Technische Universiteit Eindhoven, Eindhoven, the Netherlands
| | - Jens M. Moll
- Institute of Biochemistry and Molecular Biology II, Medical Faculty of the Heinrich-Heine-University, Düsseldorf, Germany
| | - Christian Herrmann
- Department of Physical Chemistry I, Ruhr University Bochum, Bochum, Germany
| | - Luc Brunsveld
- Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering, Technische Universiteit Eindhoven, Eindhoven, the Netherlands
| | - Roland P. Piekorz
- Institute of Biochemistry and Molecular Biology II, Medical Faculty of the Heinrich-Heine-University, Düsseldorf, Germany
| | - Mohammad R. Ahmadian
- Institute of Biochemistry and Molecular Biology II, Medical Faculty of the Heinrich-Heine-University, Düsseldorf, Germany
| |
Collapse
|
27
|
Ueda K, Xu ZJ, Miyagi N, Ono M, Wabiko H, Masuda K, Inoue M. Isolation and characterization of a carrot nucleolar protein with structural and sequence similarity to the vertebrate PESCADILLO protein. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 208:83-92. [PMID: 23683933 DOI: 10.1016/j.plantsci.2013.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Revised: 03/29/2013] [Accepted: 04/03/2013] [Indexed: 06/02/2023]
Abstract
The nuclear matrix is involved in many nuclear events, but its protein architecture in plants is still not fully understood. A cDNA clone was isolated by immunoscreening with a monoclonal antibody raised against nuclear matrix proteins of Daucus carota L. Its deduced amino acid sequence showed about 40% identity with the PESCADILLO protein of zebrafish and humans. Primary structure analysis of the protein revealed a Pescadillo N-terminus domain, a single breast cancer C-terminal domain, two nuclear localization signals, and a potential coiled-coil region as also found in animal PESCADILLO proteins. Therefore, we designated this gene DcPES1. Although DcPES1 mRNA was detected in all tissues examined, its levels were highest in tissues with proliferating cells. Immunofluorescence using specific antiserum against the recombinant protein revealed that DcPES1 localized exclusively in the nucleolus. Examination of fusion proteins with green fluorescent protein revealed that the N-terminal portion was important for localization to the nucleoli of tobacco and onion cells. Moreover, when the nuclear matrix of carrot cells was immunostained with an anti-DcPES1 serum, the signal was detected in the nucleolus. Therefore, the DcPES1 protein appears to be a component of or tightly bound to components of the nuclear matrix.
Collapse
Affiliation(s)
- Kenji Ueda
- Faculty of Bioresource Sciences, Akita Prefectural University, Akita 010-0195, Japan.
| | | | | | | | | | | | | |
Collapse
|
28
|
Song N, Ding Y, Zhuo W, He T, Fu Z, Chen Y, Song X, Fu Y, Luo Y. The nuclear translocation of endostatin is mediated by its receptor nucleolin in endothelial cells. Angiogenesis 2012; 15:697-711. [PMID: 22711211 DOI: 10.1007/s10456-012-9284-y] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 06/06/2012] [Indexed: 11/26/2022]
Abstract
Endostatin, the C-terminal fragment of collagen XVIII, is a potent anti-angiogenic factor that significantly modulates the gene expression pattern in endothelial cells. Upon cell surface binding, endostatin can not only function extracellularly, but also translocate to the nucleus within minutes. However, the mechanism by which this occurs is partially understood. Here we systematically investigated the nuclear translocation mechanism of endostatin. By chemical inhibition and RNA interference, we firstly observed that clathrin-mediated endocytosis, but not caveolae-dependent endocytosis or macropinocytosis, is essential for the nuclear translocation of endostatin. We then indentified that nucleolin and integrin α5β1, two widely accepted endostatin receptors, mediate this clathrin-dependent uptake process, which also involves urokinase plasminogen activator receptor (uPAR). Either mutagenesis study, fluorescence resonance energy transfer assay, or fluorescence cell imaging demonstrates that nucleolin and integrin α5β1 interact with uPAR simultaneously upon endostatin stimulation. Blockade of uPAR decreases not only the interaction between nucleolin and integrin α5β1, but also the uptake process, suggesting that the nucleolin/uPAR/integrin α5β1 complex facilitates the internalization of endostatin. After endocytosis, nucleolin further regulates the nuclear transport of endostatin. RNA interference and mutational analysis revealed that the nuclear translocation of endostatin involves the association of nucleolin with importin α1β1 via the nuclear localization sequence. Taken together, this study reveals the pathway by which endostatin translocates to the nucleus and the importance of nucleolin in this process, providing a new perspective for the functional investigation of the nuclear-translocated endostatin in endothelial cells.
Collapse
Affiliation(s)
- Nan Song
- National Engineering Laboratory for Anti-tumor Protein Therapeutics, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Roselló-Lletí E, Rivera M, Cortés R, Azorín I, Sirera R, Martínez-Dolz L, Hove L, Cinca J, Lago F, González-Juanatey JR, Salvador A, Portolés M. Influence of heart failure on nucleolar organization and protein expression in human hearts. Biochem Biophys Res Commun 2012; 418:222-8. [PMID: 22244875 DOI: 10.1016/j.bbrc.2011.12.151] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Accepted: 12/31/2011] [Indexed: 10/14/2022]
Abstract
We investigate for the first time the influence of heart failure (HF) on nucleolar organization and proteins in patients with ischemic (ICM) or dilated cardiomyopathy (DCM). A total of 71 human hearts from ICM (n=38) and DCM (n=27) patients, undergoing heart transplantation and control donors (n=6), were analysed by western-blotting, RT-PCR and cell biology methods. When we compared protein levels according to HF etiology, nucleolin was increased in both ICM (117%, p<0.05) and DCM (141%, p<0.01). Moreover, mRNA expression were also upregulated in ICM (1.46-fold, p<0.05) and DCM (1.70-fold, p<0.05. Immunofluorescence studies showed that the highest intensity of nucleolin was into nucleolus (p<0.0001), and it was increased in pathological hearts (p<0.0001). Ultrastructure analysis by electron microscopy showed an increase in the nucleus and nucleolus size in ICM (17%, p<0.05 and 131%, p<0.001) and DCM (56%, p<0.01 and 69%, p<0.01). Nucleolar organization was influenced by HF irrespective of etiology, increasing fibrillar centers (p<0.001), perinucleolar chromatin (p<0.01) and dense fibrillar components (p<0.01). Finally, left ventricular function parameters were related with nucleolin levels in ischemic hearts (p<0.0001). The present study demonstrates that HF influences on morphology and organization of nucleolar components, revealing changes in the expression and in the levels of nucleolin protein.
Collapse
Affiliation(s)
- Esther Roselló-Lletí
- Cardiocirculatory Unit, Research Center, Hospital Universitario La Fe, Valencia, Spain
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Peddibhotla S, Wei Z, Papineni R, Lam MH, Rosen JM, Zhang P. The DNA damage effector Chk1 kinase regulates Cdc14B nucleolar shuttling during cell cycle progression. Cell Cycle 2011; 10:671-9. [PMID: 21301228 DOI: 10.4161/cc.10.4.14901] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Chk1 is a critical effector of DNA damage checkpoints necessary for the maintenance of chromosome integrity during cell cycle progression. Here we report, that Chk1 co-localized with the nucleolar marker, fibrillarin in response to radiation-induced DNA damage in human cells. Interestingly, in vitro studies using GST pull down assays identified the dual-specificity serine/threonine nucleolar phosphatase Cdc14B as a Chk1 substrate. Furthermore, Chk1, but not a kinase-dead Chk1 control, was shown to phosphorylate Cdc14B using an in vitro kinase assay. Co-immunoprecipitation experiments using exogenous Cdc14B transfected into human cells confirmed the interaction of Cdc14B and Chk1 during cell cycle. In addition, reduction of Chk1 levels via siRNA or UCN-01 treatment demonstrated that Chk1 activation following DNA damage was required for Cdc14B export from the nucleolus. These studies have revealed a novel interplay between Chk1 kinase and Cdc14B phosphatase involving radiation-induced nucleolar shuttling to facilitate error-free cell cycle progression and prevent genomic instability.
Collapse
Affiliation(s)
- Sirisha Peddibhotla
- Department of Molecular and Cell Biology, Baylor College of Medicine, Houston, TX USA
| | | | | | | | | | | |
Collapse
|
31
|
Park R, Wang'ondu R, Heston L, Shedd D, Miller G. Efficient induction of nuclear aggresomes by specific single missense mutations in the DNA-binding domain of a viral AP-1 homolog. J Biol Chem 2011; 286:9748-62. [PMID: 21233201 DOI: 10.1074/jbc.m110.198325] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Nuclear aggresomes induced by proteins containing an expanded polyglutamine (polyQ) tract are pathologic hallmarks of certain neurodegenerative diseases. Some GFP fusion proteins lacking a polyQ tract may also induce nuclear aggresomes in cultured cells. Here we identify single missense mutations within the basic DNA recognition region of Bam HI Z E B virus replication activator (ZEBRA), an Epstein-Barr virus (EBV)-encoded basic zipper protein without a polyQ tract, that efficiently induced the formation of nuclear aggresomes. Wild-type (WT) ZEBRA was diffusely distributed within the nucleus. Four non-DNA-binding mutants, Z(R179E), Z(R183E), Z(R190E), and Z(K178D) localized to the periphery of large intranuclear spheres, to discrete nuclear aggregates, and to the cytoplasm. Other non-DNA-binding mutants, Z(N182K), Z(N182E), and Z(S186E), did not exhibit this phenotype. The interior of the spheres contained promyelocytic leukemia and HSP70 proteins. ZEBRA mutants directly induced the nuclear aggresome pathway in cells with and without EBV. Specific cellular proteins (SC35 and HDAC6) and viral proteins (WT ZEBRA, Rta, and BMLF1) but not other cellular or viral proteins were recruited to nuclear aggresomes. Co-transfection of WT ZEBRA with aggresome-inducing mutants Z(R183E) and Z(R179E) inhibited late lytic viral protein expression and lytic viral DNA amplification. This is the first reported instance in which nuclear aggresomes are induced by single missense mutations in a viral or cellular protein. We discuss conformational changes in the mutant viral AP-1 proteins that may lead to formation of nuclear aggresomes.
Collapse
Affiliation(s)
- Richard Park
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | | | | | | | | |
Collapse
|
32
|
Inhibition of early stages of HIV-1 assembly by INI1/hSNF5 transdominant negative mutant S6. J Virol 2010; 85:2254-65. [PMID: 21159874 DOI: 10.1128/jvi.00006-10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
INI1/hSNF5 is an HIV-1 integrase (IN) binding protein specifically incorporated into virions. A truncated mutant of INI1 (S6, amino acids 183 to 294) harboring the minimal IN binding Rpt1 domain potently inhibits HIV-1 particle production in a transdominant manner. The inhibition requires interaction of S6 with IN within Gag-Pol. While INI1 is a nuclear protein and harbors a masked nuclear export signal (NES), the transdominant negative mutant S6 is cytoplasmic, due to the unmasking of NES. Here, we examined the effects of subcellular localization of S6 on HIV-1 inhibition and further investigated the stages of assembly that are affected. We found that targeting a nuclear localization signal-containing S6 variant [NLS-S6(Rpt1)] to the nucleoplasm (but not to the nucleolus) resulted in complete reversal of inhibition of particle production. Electron microscopy indicated that although no electron-dense particles at any stage of assembly were seen in cells expressing S6, virions were produced in cells expressing the rescue mutant NLS-S6(Rpt1) to wild-type levels. Immunofluorescence analysis revealed that p24 exhibited a diffuse pattern of localization within the cytoplasm in cells expressing S6 in contrast to accumulation along the membrane in controls. Pulse-chase analysis indicated that in S6-expressing cells, although Gag(Pr55(gag)) protein translation was unaffected, processing and release of p24 were defective. Together, these results indicate that expression of S6 in the cytoplasm interferes with trafficking of Gag-Pol/Gag to the membrane and causes a defective processing leading to inhibition of assembly at an early stage prior to particle formation and budding.
Collapse
|
33
|
Nucleolar localization/retention signal is responsible for transient accumulation of histone H2B in the nucleolus through electrostatic interactions. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:27-38. [PMID: 21095207 DOI: 10.1016/j.bbamcr.2010.11.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 10/24/2010] [Accepted: 11/10/2010] [Indexed: 11/21/2022]
Abstract
The majority of known nuclear proteins are highly mobile. The molecular mechanisms by which they accumulate inside stable compartments that are not separated from the nucleoplasm by membranes are obscure. The compartmental retention of some proteins is associated with their biological function; however, some protein interactions within distinct nuclear structures may be non-specific. The non-specific retention may lead to the accumulation of proteins in distinct structural domains, even if the protein does not function inside this domain. In this study, we have shown that histone H2B-EGFP initially accumulated in the nucleolus after ectopic expression, and then gradually incorporated into the chromatin to leave only a small amount of nucleolus-bound histone that was revealed by removing chromatin-bound proteins with DNase I treatment. Nucleolar histone H2B had several characteristics: (i) it preferentially bound to granular component of the nucleolus and interacted with RNA or RNA-containing nucleolar components; (ii) it freely exchanged between the nucleolus and nucleoplasm; (iii) it associated with the nuclear matrix; and (iv) it bound to interphase prenuclear bodies that formed after hypotonic treatment. The region in histone H2B that acts as a nucleolar localization/retention signal (NoRS) was identified. This signal overlapped with a nuclear localization signal (NLS), which appears to be the primary function of this region. The NoRS activity of this region was non-specific, but the molecular mechanism was probably similar to the NoRSs of other nucleolar proteins. All known NoRSs are enriched with basic amino acids, and we demonstrated that positively charged motifs (nona-arginine (R9) and nona-lysine (K9)) were sufficient for the nucleolar accumulation of EGFP. Also, the correlation between measured NoRS activity and the predicted charge was observed. Thus, NoRSs appear to achieve their function through electrostatic interactions with the negatively charged components of the nucleolus. Though these interactions are non-specific, the functionally unrelated retention of a protein can increase the probability of its interaction with specific and functionally related binding sites.
Collapse
|
34
|
Hoffmann MH, Trembleau S, Muller S, Steiner G. Nucleic acid-associated autoantigens: pathogenic involvement and therapeutic potential. J Autoimmun 2009; 34:J178-206. [PMID: 20031372 DOI: 10.1016/j.jaut.2009.11.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Autoimmunity to ubiquitously expressed macromolecular nucleic acid-protein complexes such as the nucleosome or the spliceosome is a characteristic feature of systemic autoimmune diseases. Disease-specificity and/or association with clinical features of some of these autoimmune responses suggest pathogenic involvement which, however, has been proven in only a few cases so far. Although the mechanisms leading to autoimmunity against nucleic acid-containing complexes are still far from being fully understood, there is increasing experimental evidence that the nucleic acid component may act as a co-stimulator or adjuvans via activation of nucleic acid-binding receptor systems such as Toll-like receptors in antigen-presenting cells. Dysregulated apoptosis and inappropriate stimulation of nucleic acid-sensing receptors may lead to loss of tolerance against the protein components of such complexes, activation of autoreactive T cells and formation of autoantibodies. This has been demonstrated to occur in systemic lupus erythematosus and seems to represent a general mechanism that may be crucial for the development of systemic autoimmune diseases. This review provides a comprehensive overview of the most thoroughly-characterized nucleic acid-associated autoantigens, describing their structure and biological function, as well as the nature and pathogenic importance of the reactivities directed against them. Furthermore, recent advances in immunotherapy such as antigen-specific approaches targeted at nucleic acid-binding antigens are discussed.
Collapse
Affiliation(s)
- Markus H Hoffmann
- Division of Rheumatology, Internal Medicine III, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | | | | | | |
Collapse
|
35
|
Kass-Simon G, Zompa MA, Scappaticci AA, Zackroff RV, Hufnagel LA. Nucleolar binding of an anti-NMDA receptor antibody in hydra: a non-canonical role for an NMDA receptor protein? ACTA ACUST UNITED AC 2009; 311:763-75. [PMID: 19658087 DOI: 10.1002/jez.563] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Two emerging concepts in cell biology are the back-and-forth trafficking of receptor proteins and nuclear transcription factors between the nucleus and the cell membrane, and the alternative splicing of messenger RNA to produce similar proteins targeted to different cell sites. Recent evidence suggests that the nucleolus is a dynamic structure whose components may be involved in both types of trafficking. In the nervous system of higher animals, the N-methyl-D-aspartate (NMDA)-specific glutamate receptor has various roles in development and cell communication. It is involved in learning, memory, axonal guidance and nerve regeneration. We have reported earlier that the NR1 subunit of the NMDA receptor is present in the cell periphery and the nucleus of stem cells, neurons and epitheliomuscular cells of the early-evolved cnidarian, Hydra vulgaris (Scappaticci et al., 2004. Cell Tissue Res 316:263-270); it is involved in coordinating hydra's neuroeffector systems (Kass-Simon and Scappaticci, 2003. Hydrobiologia 530/531:67-71; Pierobon et al., 2004. Eur J Neurosci 20:2598-2604; Scappaticci and Kass-Simon, 2008. Comp Biochem Physiol A 150:415-422; Kay and Kass-Simon, 2009. Bio Bull 216:113-129). Here we report immunocytochemical experiments, using a mouse monoclonal antibody raised against the mammalian NR1 receptor subunit, and an in silico genomic and gene expression analysis identifying the homologues in hydra of mammalian NR1 and fibrillarin (FBL) genes, and their expressed proteins. The experiments reveal that the NR1 antibody specifically labels the nucleoli of large and small interstitial cells (stem cells), nematoblasts, neuroblasts, and epitheliomusclar cells; antibody labeling of the nucleolar marker, FBL, confirms the nucleolar localization of NR1 antibody labeling. Genomic analysis reveals that NR1 and FBL genes are conserved in hydra, and suggests that there are at least two NR1 splice variants, one of which contains both nuclear and nucleolar targeting signals. The finding that an NR1 receptor subunit (or a portion of it) appears in nucleoli of hydra cells is unique, and has not been reported for any other organism. Its presence in nucleoli of hydra may signal the existence of a yet-undescribed shuttle mechanism between the cell surface and the nucleous, or the alternative deployment of NR1 splice variants to different cell sites.
Collapse
Affiliation(s)
- Gabriele Kass-Simon
- Department of Biological Sciences, University of Rhode Island, Morrill Hall, Kingston, RI 02881, USA.
| | | | | | | | | |
Collapse
|
36
|
Houmani JL, Ruf IK. Clusters of basic amino acids contribute to RNA binding and nucleolar localization of ribosomal protein L22. PLoS One 2009; 4:e5306. [PMID: 19390581 PMCID: PMC2668802 DOI: 10.1371/journal.pone.0005306] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Accepted: 03/26/2009] [Indexed: 11/19/2022] Open
Abstract
The ribosomal protein L22 is a component of the 60S eukaryotic ribosomal subunit. As an RNA-binding protein, it has been shown to interact with both cellular and viral RNAs including 28S rRNA and the Epstein-Barr virus encoded RNA, EBER-1. L22 is localized to the cell nucleus where it accumulates in nucleoli. Although previous studies demonstrated that a specific amino acid sequence is required for nucleolar localization, the RNA-binding domain has not been identified. Here, we investigated the hypothesis that the nucleolar accumulation of L22 is linked to its ability to bind RNA. To address this hypothesis, mutated L22 proteins were generated to assess the contribution of specific amino acids to RNA binding and protein localization. Using RNA-protein binding assays, we demonstrate that basic amino acids 80-93 are required for high affinity binding of 28S rRNA and EBER-1 by L22. Fluorescence localization studies using GFP-tagged mutated L22 proteins further reveal that basic amino acids 80-93 are critical for nucleolar accumulation and for incorporation into ribosomes. Our data support the growing consensus that the nucleolar accumulation of ribosomal proteins may not be mediated by a defined localization signal, but rather by specific interaction with established nucleolar components such as rRNA.
Collapse
Affiliation(s)
- Jennifer L. Houmani
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California, United States of America
| | - Ingrid K. Ruf
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California, United States of America
- * E-mail:
| |
Collapse
|
37
|
Emmott E, Hiscox JA. Nucleolar targeting: the hub of the matter. EMBO Rep 2009; 10:231-8. [PMID: 19229283 DOI: 10.1038/embor.2009.14] [Citation(s) in RCA: 218] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Accepted: 01/26/2009] [Indexed: 11/09/2022] Open
Abstract
The nucleolus is a dynamic structure that has roles in various processes, from ribosome biogenesis to regulation of the cell cycle and the cellular stress response. Such functions are frequently mediated by the sequestration or release of nucleolar proteins. Our understanding of protein targeting to the nucleolus is much less complete than our knowledge of membrane-spanning translocation systems--such as those involved in nuclear targeting--and the experimental evidence reveals that few parallels exist with these better-characterized systems. Here, we discuss the current understanding of nucleolar targeting, explore the types of sequence that control the localization of a protein to the nucleolus, and speculate that certain subsets of nucleolar proteins might act as hub proteins that are able to bind to multiple protein targets. In parallel to other subnuclear structures, such as PML bodies, the proteins that are involved in the formation and maintenance of the nucleolus are inexorably linked to nucleolar trafficking.
Collapse
Affiliation(s)
- Edward Emmott
- Institute of Molecular and Cellular Biology, Faculty of Biological Sciences, Garstang Building, University of Leeds, Leeds LS2 9JT, England, UK
| | | |
Collapse
|
38
|
Liu Z, Kenworthy R, Green C, Tang H. Molecular determinants of nucleolar translocation of RNA helicase A. Exp Cell Res 2007; 313:3743-54. [PMID: 17822697 DOI: 10.1016/j.yexcr.2007.07.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 07/11/2007] [Accepted: 07/27/2007] [Indexed: 11/30/2022]
Abstract
RNA helicase A (RHA) is a member of the DEAH-box family of DNA/RNA helicases involved in multiple cellular processes and the life cycles of many viruses. The subcellular localization of RHA is dynamic despite its steady-state concentration in the nucleoplasm. We have previously shown that it shuttles rapidly between the nucleus and the cytoplasm by virtue of a bidirectional nuclear transport domain (NTD) located in its carboxyl terminus. Here, we investigate the molecular determinants for its translocation within the nucleus and, more specifically, its redistribution from the nucleoplasm to nucleolus or the perinucleolar region. We found that low temperature treatment, transcription inhibition or replication of hepatitis C virus caused the intranuclear redistribution of the protein, suggesting that RHA shuttles between the nucleolus and nucleoplasm and becomes trapped in the nucleolus or the perinucleolar region upon blockade of transport to the nucleoplasm. Both the NTD and ATPase activity were essential for RHA's transport to the nucleolus or perinucleolar region. One of the double-stranded RNA binding domains (dsRBD II) was also required for this nucleolar translocation (NoT) phenotype. RNA interference studies revealed that RHA is essential for survival of cultured hepatoma cells and the ATPase activity appears to be important for this critical role.
Collapse
Affiliation(s)
- Zhe Liu
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4370, USA
| | | | | | | |
Collapse
|
39
|
Petricka JJ, Nelson TM. Arabidopsis nucleolin affects plant development and patterning. PLANT PHYSIOLOGY 2007; 144:173-86. [PMID: 17369435 PMCID: PMC1913809 DOI: 10.1104/pp.106.093575] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2006] [Accepted: 03/13/2007] [Indexed: 05/14/2023]
Abstract
Nucleolin is a major nucleolar protein implicated in many aspects of ribosomal biogenesis, including early events such as processing of the large 35S preribosomal RNA. We found that the Arabidopsis (Arabidopsis thaliana) parallel1 (parl1) mutant, originally identified by its aberrant leaf venation, corresponds to the Arabidopsis nucleolin gene. parl1 mutants display parallel leaf venation, aberrant localization of the provascular marker Athb8:beta-glucuronidase, the auxin-sensitive reporter DR5:beta-glucuronidase, and auxin-dependent growth defects. PARL1 is highly similar to the yeast (Saccharomyces cerevisiae) nucleolin NUCLEAR SIGNAL RECOGNITION 1 (NSR1) multifunctional protein; the Arabidopsis PARL1 gene can rescue growth defects of yeast nsr1 null mutants. This suggests that PARL1 protein may have roles similar to those of the yeast nucleolin in nuclear signal recognition, ribosomal processing, and ribosomal subunit accumulation. Based on the range of auxin-related defects in parl1 mutants, we propose that auxin-dependent organ growth and patterning is highly sensitive to the efficiency of nucleolin-dependent ribosomal processing.
Collapse
Affiliation(s)
- Jalean Joyanne Petricka
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520-8104, USA
| | | |
Collapse
|
40
|
Rickards B, Flint SJ, Cole MD, LeRoy G. Nucleolin is required for RNA polymerase I transcription in vivo. Mol Cell Biol 2007; 27:937-48. [PMID: 17130237 PMCID: PMC1800701 DOI: 10.1128/mcb.01584-06] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 10/04/2006] [Accepted: 11/14/2006] [Indexed: 11/20/2022] Open
Abstract
Eukaryotic genomes are packaged with histones and accessory proteins in the form of chromatin. RNA polymerases and their accessory proteins are sufficient for transcription of naked DNA, but not of chromatin, templates in vitro. In this study, we purified and identified nucleolin as a protein that allows RNA polymerase II to transcribe nucleosomal templates in vitro. As immunofluorescence confirmed that nucleolin localizes primarily to nucleoli with RNA polymerase I, we demonstrated that nucleolin allows RNA polymerase I transcription of chromatin templates in vitro. The results of chromatin immunoprecipitation experiments established that nucleolin is associated with chromatin containing rRNA genes transcribed by RNA polymerase I but not with genes transcribed by RNA polymerase II or III. Knockdown of nucleolin by RNA interference resulted in specific inhibition of RNA polymerase I transcription. We therefore propose that an important function of nucleolin is to permit RNA polymerase I to transcribe nucleolar chromatin.
Collapse
Affiliation(s)
- Brenden Rickards
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | | | | | | |
Collapse
|
41
|
Goyal P, Pandey D, Siess W. Phosphorylation-dependent regulation of unique nuclear and nucleolar localization signals of LIM kinase 2 in endothelial cells. J Biol Chem 2006; 281:25223-30. [PMID: 16820362 DOI: 10.1074/jbc.m603399200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
LIM kinases (LIMKs) regulate actin dynamics through cofilin phosphorylation and also have a function in the nucleus. Recently we have shown that LIMK2 shuttles between cytoplasm and nucleus in endothelial cells and that nuclear import is inhibited by protein kinase C-mediated phosphorylation of Ser-283. Here we aimed to identify the structural features of LIMK2 responsible for nuclear import. We found that the kinase domain of LIMK2 is localized exclusively in the nucleus and, in contrast to the kinase domain of LIMK1, it accumulated in the nucleolus. Through site-directed mutagenesis, we identified the basic amino acid-rich motif KKRTLRKNDRKKR (amino acids 491-503) as the functional nuclear and nucleolar localization signal of LIMK2. After fusing this motif to enhanced green fluorescent protein, the fusion protein localized exclusively in the nucleus and nucleolus. Mutagenesis studies showed that phosphorylation of Thr-494, a putative protein kinase C phosphorylation site identified within the nuclear localization signal, inhibits nuclear import of the enhanced green fluorescent protein-PDZ kinase domain of LIMK2. After inhibiting nuclear export with leptomycin B, phosphorylation of either Ser-283 or Thr-494 reduced the nuclear import of LIMK2. Phosphorylation of both Ser-283 and Thr-494 sites inhibited nuclear import completely. Our findings identify a unique basic amino acid-rich motif (amino acids 491-503) in LIMK2 which is not present in LIMK1 that serves to target the protein not only to the nucleus but also to the nucleolus. Phosphorylation of Thr-494 within this motif negatively regulates nuclear import of LIMK2.
Collapse
Affiliation(s)
- Pankaj Goyal
- Institute for Prevention of Cardiovascular Diseases, University of Munich, 80336 Munich, Germany.
| | | | | |
Collapse
|
42
|
Torrano V, Navascués J, Docquier F, Zhang R, Burke LJ, Chernukhin I, Farrar D, León J, Berciano MT, Renkawitz R, Klenova E, Lafarga M, Delgado MD. Targeting of CTCF to the nucleolus inhibits nucleolar transcription through a poly(ADP-ribosyl)ation-dependent mechanism. J Cell Sci 2006; 119:1746-59. [PMID: 16595548 DOI: 10.1242/jcs.02890] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Multiple functions have been reported for the transcription factor and candidate tumour suppressor, CTCF. Among others, they include regulation of cell growth, differentiation and apoptosis, enhancer-blocking activity and control of imprinted genes. CTCF is usually localized in the nucleus and its subcellular distribution during the cell cycle is dynamic; CTCF was found associated with mitotic chromosomes and the midbody, suggesting different roles for CTCF at different stages of the cell cycle. Here we report the nucleolar localization of CTCF in several experimental model systems. Translocation of CTCF from nucleoplasm to the nucleolus was observed after differentiation of K562 myeloid cells and induction of apoptosis in MCF7 breast cancer cells. CTCF was also found in the nucleoli in terminally differentiated rat trigeminal ganglion neurons. Thus our data show that nucleolar localization of CTCF is associated with growth arrest. Interestingly, the 180 kDa poly(ADP-ribosyl)ated isoform of CTCF was predominantly found in the nucleoli fractions. By transfecting different CTCF deletion constructs into cell lines of different origin we demonstrate that the central zinc-finger domain of CTCF is the region responsible for nucleolar targeting. Analysis of subnucleolar localization of CTCF revealed that it is distributed homogeneously in both dense fibrillar and granular components of the nucleolus, but is not associated with fibrillar centres. RNA polymerase I transcription and protein synthesis were required to sustain nucleolar localization of CTCF. Notably, the labelling of active transcription sites by in situ run-on assays demonstrated that CTCF inhibits nucleolar transcription through a poly(ADP-ribosyl)ation-dependent mechanism.
Collapse
Affiliation(s)
- Verónica Torrano
- Grupo de Biología Molecular del Cáncer, Departamento de Biologia Molecular, Universidad de Cantabria, 39011-Santander, Spain
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Ramos A, Hollingworth D, Adinolfi S, Castets M, Kelly G, Frenkiel TA, Bardoni B, Pastore A. The structure of the N-terminal domain of the fragile X mental retardation protein: a platform for protein-protein interaction. Structure 2006; 14:21-31. [PMID: 16407062 DOI: 10.1016/j.str.2005.09.018] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2005] [Revised: 09/06/2005] [Accepted: 09/09/2005] [Indexed: 10/25/2022]
Abstract
FMRP, whose lack of expression causes the X-linked fragile X syndrome, is a modular RNA binding protein thought to be involved in posttranslational regulation. We have solved the structure in solution of the N-terminal domain of FMRP (NDF), a functionally important region involved in multiple interactions. The structure consists of a composite fold comprising two repeats of a Tudor motif followed by a short alpha helix. The interactions between the three structural elements are essential for the stability of the NDF fold. Although structurally similar, the two repeats have different dynamic and functional properties. The second, more flexible repeat is responsible for interacting both with methylated lysine and with 82-FIP, one of the FMRP nuclear partners. NDF contains a 3D nucleolar localization signal, since destabilization of its fold leads to altered nucleolar localization of FMRP. We suggest that the NDF composite fold determines an allosteric mechanism that regulates the FMRP functions.
Collapse
Affiliation(s)
- Andres Ramos
- Molecular Structure Division, National Institute for Medical Research, London NW7 1AA, UK
| | | | | | | | | | | | | | | |
Collapse
|
44
|
Renvoisé B, Khoobarry K, Gendron MC, Cibert C, Viollet L, Lefebvre S. Distinct domains of the spinal muscular atrophy protein SMN are required for targeting to Cajal bodies in mammalian cells. J Cell Sci 2006; 119:680-92. [PMID: 16449324 DOI: 10.1242/jcs.02782] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Mutations of the survival motor neuron gene SMN1 cause the inherited disease spinal muscular atrophy (SMA). The ubiquitous SMN protein facilitates the biogenesis of spliceosomal small nuclear ribonucleoproteins (snRNPs). The protein is detected in the cytoplasm, nucleoplasm and enriched with snRNPs in nuclear Cajal bodies. It is structurally divided into at least an amino-terminal region rich in basic amino acid residues, a central Tudor domain, a self-association tyrosine-glycine-box and an exon7-encoded C-terminus. To examine the domains required for the intranuclear localization of SMN, we have used fluorescently tagged protein mutants transiently overexpressed in mammalian cells. The basic amino acid residues direct nucleolar localization of SMN mutants. The Tudor domain promotes localization of proteins in the nucleus and it cooperates with the basic amino acid residues and the tyrosine-glycine-box for protein localization in Cajal bodies. Moreover, the most frequent disease-linked mutant SMNΔex7 reduces accumulation of snRNPs in Cajal bodies, suggesting that the C-terminus of SMN participates in targeting to Cajal bodies. A reduced number of Cajal bodies in patient fibroblasts associates with the absence of snRNPs in Cajal bodies, revealing that intranuclear snRNA organization is modified in disease. These results indicate that direct and indirect mechanisms regulate localization of SMN in Cajal bodies.
Collapse
Affiliation(s)
- Benoît Renvoisé
- Laboratoire de Biologie Cellulaire des Membranes, Institut Jacques Monod (IJM), UMR 7592 CNRS/Universités Paris 6 et 7, 2 Place Jussieu, 75251 Paris Cedex 05, France
| | | | | | | | | | | |
Collapse
|
45
|
Turck N, Lefebvre O, Gross I, Gendry P, Kedinger M, Simon-Assmann P, Launay JF. Effect of laminin-1 on intestinal cell differentiation involves inhibition of nuclear nucleolin. J Cell Physiol 2006; 206:545-55. [PMID: 16245305 DOI: 10.1002/jcp.20501] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Intestinal epithelial cells are characterized by continuous renewal and differentiation events, which may be influenced by the basement membrane, and in particular laminins, which are major components of this specialized extracellular matrix. The function and signaling pathways of laminins in these processes are still poorly documented. In this study, we investigated the possible role and the subcellular localization of nucleolin, a nuclear shuttling protein, in relation to differentiation of human intestinal epithelial Caco2/TC7 cells triggered by exogenous laminin-1. Immunofluorescence and Western blot analysis indicated that laminin-1 induced early differentiation of the cells concomitantly to a decrease in nuclear nucleolin and its a cell surface location. We also showed that both effects of laminin-1 on Caco2/TC7 cells--induction of the differentiation marker sucrase-isomaltase and redistribution of nucleolin--could be mediated by a beta1-integrin dependent cascade that implicated activation of the p38 MAPK pathway. In addition, knock-down of nucleolin expression by the small interfering RNA strategy mimicked the effect of laminin-1 as it resulted in the induction of cell polarization and differentiation. Thus, our study suggests that changes in the subcellular distribution and expression level of nucleolin play an important role in intestinal cell differentiation and relay the signaling pathway induced by laminin-1.
Collapse
Affiliation(s)
- Natacha Turck
- Inserm, U682, Strasbourg F-67200 France; Univ. Louis Pasteur, Strasbourg, F-67200 France
| | | | | | | | | | | | | |
Collapse
|
46
|
Yu B, Mitchell GA, Richter A. Nucleolar localization of cirhin, the protein mutated in North American Indian childhood cirrhosis. Exp Cell Res 2005; 311:218-28. [PMID: 16225863 DOI: 10.1016/j.yexcr.2005.08.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2005] [Revised: 08/22/2005] [Accepted: 08/23/2005] [Indexed: 10/25/2022]
Abstract
Cirhin (NP_116219), the product of the CIRH1A gene is mutated in North American Indian childhood cirrhosis (NAIC/CIRH1A, OMIM 604901), a severe autosomal recessive intrahepatic cholestasis. It is a 686-amino-acid WD40-repeat containing protein of unknown function that is predicted to contain multiple targeting signals, including an N-terminal mitochondrial targeting signal, a C-terminal monopartite nuclear localization signal (NLS) and a bipartite nuclear localization signal (BNLS). We performed the direct determination of subcellular localization of cirhin as a crucial first step in unraveling its biological function. Using EGFP and His-tagged cirhin fusion proteins expressed in HeLa and HepG2, cells we show that cirhin is a nucleolar protein and that the R565W mutation, for which all NAIC patients are homozygous, has no effect on subcellular localization. Cirhin has an active C-terminal monopartite nuclear localization signal (NLS) and a unique nucleolar localization signal (NrLS) between residues 315 and 432. The nucleolus is not known to be important specifically for intrahepatic cholestasis. These observations provide a new dimension in the study of hereditary cholestasis.
Collapse
Affiliation(s)
- Bin Yu
- Service de Génétique médicale, Centre de recherche, Hôpital Sainte-Justine, Université de Montréal, 3175 Côte Sainte-Catherine, Québec, Canada H3T1C5
| | | | | |
Collapse
|
47
|
Libault M, Tessadori F, Germann S, Snijder B, Fransz P, Gaudin V. The Arabidopsis LHP1 protein is a component of euchromatin. PLANTA 2005; 222:910-25. [PMID: 16244868 DOI: 10.1007/s00425-005-0129-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2005] [Accepted: 08/29/2005] [Indexed: 05/05/2023]
Abstract
The HP1 family proteins are involved in several aspects of chromatin function and regulation in Drosophila, mammals and the fission yeast. Here we investigate the localization of LHP1, the unique Arabidopsis thaliana HP1 homolog known at present time, to approach its function. A functional LHP1-GFP fusion protein, able to restore the wild-type phenotype in the lhp1 mutant, was used to analyze the subnuclear distribution of LHP1 in both A. thaliana and Nicotiana tabacum. In A. thaliana interphase nuclei, LHP1 was predominantly located outside the heterochromatic chromocenters. No major aberrations were observed in heterochromatin content or chromocenter organization in lhp1 plants. These data indicate that LHP1 is mainly involved in euchromatin organization in A. thaliana. In tobacco BY-2 cells, the LHP1 distribution, although in foci, slightly differed suggesting that LHP1 localization is determined by the underlying genome organization of plant species. Truncated LHP1 proteins expressed in vivo allowed us to determine the function of the different segments in the localization. The in foci distribution is dependent on the presence of the two chromo domains, whereas the hinge region has some nucleolus-targeting properties. Furthermore, like the animal HP1beta and HP1gamma subtypes, LHP1 dissociates from chromosomes during mitosis. In transgenic plants expressing the LHP1-GFP fusion protein, two major localization patterns were observed according to cell types suggesting that localization evolves with age or differentiation states. Our results show conversed characteristics of the A. thaliana HP1 homolog with the mammal HP1gamma isoform, besides specific plant properties.
Collapse
Affiliation(s)
- Marc Libault
- Laboratoire de Biologie Cellulaire, IJPB, INRA, route de St Cyr, 78026, Versailles Cedex, France
| | | | | | | | | | | |
Collapse
|
48
|
Song Z, Wu M. Identification of a novel nucleolar localization signal and a degradation signal in Survivin-deltaEx3: a potential link between nucleolus and protein degradation. Oncogene 2005; 24:2723-34. [PMID: 15735764 DOI: 10.1038/sj.onc.1208097] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
For a long time, as the most prominent subnuclear structure, nucleolus has been recognized as a main site where rRNA processing and ribosomal subunit assemblies take place. It has not been until recently that additional functions of nucleolus have begun to be proposed. In this study, we for the first time demonstrate that Survivin-deltaEx3, a novel functionally splice variant of Survivin localizes in the nucleoli where it degrades rapidly through ubiquitin-proteosome pathway. Several lines of evidences provided in this report support this finding (i) a novel nucleolar localization sequence (NoLS, MQRKPTIRRKNLRLRRK) and a novel degradation signal (aa92-aa137) within Survivin-deltaEx3 were identified (ii) proteasome inhibitors MG132 or ALLN greatly inhibits degradation of Survivin-deltaEx3 and polyubiquitination of Survivin-deltaEx3 was detected (iii) heterologous proteins such as TAT-PTD or p14ARF, when fused to this putative degradation signal, result in a significant degradation within the nucleolus. In addition, the nucleolar localization and degradation of Survivin-deltaEx3 appear to be required for its antiapoptotic function, since neither NoLS-deleted nor degradation signal-deleted Survivin-deltaEx3 retains protective effect against Doxorubicin-induced apoptosis. Thus, our results have provided evidences to suggest that besides cytosol, nucleus, endoplsmic reticulum (ER) or lysosomes, nucleolus may also operate important protein degradation pathway, which has been overlooked previously.
Collapse
Affiliation(s)
- Zhiyin Song
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | | |
Collapse
|
49
|
Dai L, Dai L, Xu D, Yao X, Lu Y, Xu Z. Conformational determinants of the intracellular localization of midkine. Biochem Biophys Res Commun 2005; 330:310-7. [PMID: 15781266 DOI: 10.1016/j.bbrc.2005.02.155] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2005] [Indexed: 11/23/2022]
Abstract
Midkine (MK) is a multifunctional growth factor and has been discovered to play important roles in carcinogenesis. MK has been reported to localize to the nucleus and nucleolus, however, the data are not consistent and the signals responsible for the localization are unknown. Here we reported that human MK exclusively localized to the nucleus and nucleolus in HepG2 cells by using GFP as a tracking molecule. In order to identify the motifs required for the nuclear localization and nucleolar accumulation, point- and deletion-mutations were introduced and the corresponding subcellular localizations were analyzed. Data revealed that (i) K79R81, K86K87, and the C-terminal tail of MK constitute the nuclear localization determinant of MK, and (ii) the C-terminal tail is the key element controlling MK nucleolar accumulation though the N-terminal tail, K79R81, and K86K87 also contribute to this process. Taken together, our results provide the first documentation about the determinants required for MK nuclear and nucleolar localization.
Collapse
Affiliation(s)
- Licheng Dai
- Huzhou Central Hospital, Huzhou 313000 [corrected] China
| | | | | | | | | | | |
Collapse
|
50
|
Carpentier M, Morelle W, Coddeville B, Pons A, Masson M, Mazurier J, Legrand D. Nucleolin undergoes partial N- and O-glycosylations in the extranuclear cell compartment. Biochemistry 2005; 44:5804-15. [PMID: 15823039 DOI: 10.1021/bi047831s] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nucleolin is an ubiquitous, nonhistone nucleolar phosphoprotein involved in fundamental aspects of transcription regulation, cell proliferation, and growth. Nucleolin was primarily found in the nucleus, but it was also proposed as a possible shuttle between the nucleus, cytoplasm, and cell membrane. We report here that part of the extranuclear nucleolin undergoes complex N- and O-glycosylations. A band with higher molecular mass (113 kDa) than the 105-kDa classical major nucleolin band was detected on SDS-PAGE gel that cross-reacted with specific anti-nucleolin antibodies and was identified as a nucleolin isoform by mass spectrometry. The presence of N-glycans was first suggested by sensibility of the 113-kDa nucleolin isoform to tunicamycin treatment. Determination of monosaccharide composition by heptafluorobutyrate derivation followed by gas-chromatography mass spectrometry indicated the presence of N- and O-glycans. The structures of N- and O-glycans were first investigated using specificity of binding to lectins. This approach allowed a partial characterization of N-glycan structures and revealed O-glycan structures that could otherwise go unnoticed. Further study of N-glycans by mass spectrometry using direct exoglycosidase treatment on MALDI-TOF target allowed the complete definition of their structures. Finally, the use of peptide mass fingerprinting with sinapinic acid allowed identification of N317 and N492 as the two N-glycosylation sites. N317 and N492 belong to RNA-binding domains 1 and 3 of nucleolin, respectively, that suggests a role of glycosylation in regulating the function of the protein.
Collapse
Affiliation(s)
- Mathieu Carpentier
- Unité de Glycobiologie Structurale et Fonctionnelle, Institut Fédératif de Recherche 118, Université des Sciences et Technologies de Lille, 59655 Villeneuve d'Ascq Cedex, France
| | | | | | | | | | | | | |
Collapse
|