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Ruan K, Bai G, Fang Y, Li D, Li T, Liu X, Lu B, Lu Q, Songyang Z, Sun S, Wang Z, Zhang X, Zhou W, Zhang H. Biomolecular condensates and disease pathogenesis. SCIENCE CHINA. LIFE SCIENCES 2024; 67:1792-1832. [PMID: 39037698 DOI: 10.1007/s11427-024-2661-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Accepted: 06/21/2024] [Indexed: 07/23/2024]
Abstract
Biomolecular condensates or membraneless organelles (MLOs) formed by liquid-liquid phase separation (LLPS) divide intracellular spaces into discrete compartments for specific functions. Dysregulation of LLPS or aberrant phase transition that disturbs the formation or material states of MLOs is closely correlated with neurodegeneration, tumorigenesis, and many other pathological processes. Herein, we summarize the recent progress in development of methods to monitor phase separation and we discuss the biogenesis and function of MLOs formed through phase separation. We then present emerging proof-of-concept examples regarding the disruption of phase separation homeostasis in a diverse array of clinical conditions including neurodegenerative disorders, hearing loss, cancers, and immunological diseases. Finally, we describe the emerging discovery of chemical modulators of phase separation.
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Affiliation(s)
- Ke Ruan
- The First Affiliated Hospital & School of Life Sciences, Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, Hefei National Research Center for Interdisciplinary Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230027, China.
| | - Ge Bai
- Nanhu Brain-computer Interface Institute, Hangzhou, 311100, China.
- Department of Neurology of Second Affiliated Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China.
| | - Yanshan Fang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 201210, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Dan Li
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, 200030, China.
| | - Tingting Li
- Department of Biomedical Informatics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China.
| | - Xingguo Liu
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.
- Joint School of Life Sciences, Guangzhou Medical University, Guangzhou, 510000, China.
| | - Boxun Lu
- Neurology Department at Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, School of Life Sciences, Fudan University, Shanghai, 200433, China.
| | - Qing Lu
- Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Institutes, Shanghai Jiao Tong University, Shanghai, 200030, China.
| | - Zhou Songyang
- State Key Laboratory of Biocontrol, MOE Key Laboratory of Gene Function and Regulation and Guangzhou Key Laboratory of Healthy Aging Research, School of Life Sciences, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, 510275, China.
| | - Shuguo Sun
- Department of Human Anatomy, Histology and Embryology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Zheng Wang
- The Second Affiliated Hospital, School of Basic Medical Sciences, Institute of Biomedical Innovation, Jiangxi Medical College, Nanchang University, Nanchang, 330031, China.
| | - Xin Zhang
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, 310024, China.
| | - Wen Zhou
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, 518055, China.
| | - Hong Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
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2
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Lang R, Hodgson RE, Shelkovnikova TA. TDP-43 in nuclear condensates: where, how, and why. Biochem Soc Trans 2024; 52:1809-1825. [PMID: 38958608 DOI: 10.1042/bst20231447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 06/12/2024] [Accepted: 06/17/2024] [Indexed: 07/04/2024]
Abstract
TDP-43 is an abundant and ubiquitously expressed nuclear protein that becomes dysfunctional in a spectrum of neurodegenerative diseases. TDP-43's ability to phase separate and form/enter biomolecular condensates of varying size and composition is critical for its functionality. Despite the high density of phase-separated assemblies in the nucleus and the nuclear abundance of TDP-43, our understanding of the condensate-TDP-43 relationship in this cellular compartment is only emerging. Recent studies have also suggested that misregulation of nuclear TDP-43 condensation is an early event in the neurodegenerative disease amyotrophic lateral sclerosis. This review aims to draw attention to the nuclear facet of functional and aberrant TDP-43 condensation. We will summarise the current knowledge on how TDP-43 containing nuclear condensates form and function and how their homeostasis is affected in disease.
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Affiliation(s)
- Ruaridh Lang
- Sheffield Institute for Translational Neuroscience (SITraN) and Neuroscience Institute, University of Sheffield, Sheffield, U.K
| | - Rachel E Hodgson
- Sheffield Institute for Translational Neuroscience (SITraN) and Neuroscience Institute, University of Sheffield, Sheffield, U.K
| | - Tatyana A Shelkovnikova
- Sheffield Institute for Translational Neuroscience (SITraN) and Neuroscience Institute, University of Sheffield, Sheffield, U.K
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3
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Kang HW, Nguyen L, An S, Kyoung M. Mechanistic insights into condensate formation of human liver-type phosphofructokinase by stochastic modeling approaches. Sci Rep 2024; 14:19011. [PMID: 39152221 PMCID: PMC11329711 DOI: 10.1038/s41598-024-69534-w] [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: 10/05/2023] [Accepted: 08/06/2024] [Indexed: 08/19/2024] Open
Abstract
Human liver-type phosphofructokinase 1 (PFKL) has been shown to regulate glucose flux as a scaffolder arranging glycolytic and gluconeogenic enzymes into a multienzyme metabolic condensate, the glucosome. However, it has remained elusive of how phase separation of PFKL is governed and initiates glucosome formation in living cells, thus hampering to understand a mechanism of glucosome formation and its functional contribution to human cells. In this work, we developed a stochastic model in silico using the principle of Langevin dynamics to investigate how biological properties of PFKL contribute to the condensate formation. The significance of an intermolecular interaction between PFKLs, an effective concentration of PFKL at a region of interest, and its own self-assembled filaments in formation of PFKL condensates and control of their sizes were demonstrated by molecular dynamics simulation using the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). Such biological properties that define intracellular dynamics of PFKL appear to be essential for phase separation of PFKL, which may represent an initiation step for the formation of glucosome condensates. Collectively, our computational study provides mechanistic insights of glucosome formation, particularly an initial stage through the formation of PFKL condensates in living human cells.
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Affiliation(s)
- Hye-Won Kang
- Department of Mathematics and Statistics, University of Maryland Baltimore County (UMBC), 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
| | - Luan Nguyen
- Department of Mathematics and Statistics, University of Maryland Baltimore County (UMBC), 1000 Hilltop Circle, Baltimore, MD, 21250, USA
| | - Songon An
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County (UMBC), 1000 Hilltop Circle, Baltimore, MD, 21250, USA
- Program in Oncology, Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland, Baltimore, MD, 21201, USA
| | - Minjoung Kyoung
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County (UMBC), 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
- Program in Oncology, Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland, Baltimore, MD, 21201, USA.
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Chen X, Seyboldt R, Sommer JU, Jülicher F, Harmon T. Droplet Differentiation by a Chemical Switch. PHYSICAL REVIEW LETTERS 2024; 133:028402. [PMID: 39073969 DOI: 10.1103/physrevlett.133.028402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 05/29/2024] [Indexed: 07/31/2024]
Abstract
A fundamental question about biomolecular condensates is how distinct condensates can emerge from the interplay of different components. Here we present a minimal model of droplet differentiation where phase separated droplets demix into two types with different chemical modifications triggered by enzymatic reactions. We use numerical solutions to Cahn-Hilliard equations with chemical reactions and an effective droplet model to reveal the switchlike behavior. Our work shows how condensate identities in cells could result from competing enzymatic actions.
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Affiliation(s)
| | | | - Jens-Uwe Sommer
- Leibniz-Institut für Polymerforschung, Institut Theorie der Polymere, 01069 Dresden, Germany
- Cluster of Excellence Physics of Life, TU Dresden, 01062 Dresden, Germany
- Institute for Theoretical Physics, TU Dresden, Zellescher Weg 17, 01069 Dresden, Germany
| | - Frank Jülicher
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzerstrasse 38, 01187 Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
- Center for Systems Biology Dresden, 01307 Dresden, Germany
- Cluster of Excellence Physics of Life, TU Dresden, 01062 Dresden, Germany
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Bermudez Y, Hatfield D, Muller M. A Balancing Act: The Viral-Host Battle over RNA Binding Proteins. Viruses 2024; 16:474. [PMID: 38543839 PMCID: PMC10974049 DOI: 10.3390/v16030474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 03/16/2024] [Accepted: 03/18/2024] [Indexed: 04/01/2024] Open
Abstract
A defining feature of a productive viral infection is the co-opting of host cell resources for viral replication. Despite the host repertoire of molecular functions and biological counter measures, viruses still subvert host defenses to take control of cellular factors such as RNA binding proteins (RBPs). RBPs are involved in virtually all steps of mRNA life, forming ribonucleoprotein complexes (mRNPs) in a highly ordered and regulated process to control RNA fate and stability in the cell. As such, the hallmark of the viral takeover of a cell is the reshaping of RNA fate to modulate host gene expression and evade immune responses by altering RBP interactions. Here, we provide an extensive review of work in this area, particularly on the duality of the formation of RNP complexes that can be either pro- or antiviral. Overall, in this review, we highlight the various ways viruses co-opt RBPs to regulate RNA stability and modulate the outcome of infection by gathering novel insights gained from research studies in this field.
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Affiliation(s)
| | | | - Mandy Muller
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA; (Y.B.); (D.H.)
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Sharma G, Paganin M, Lauria F, Perenthaler E, Viero G. The SMN-ribosome interplay: a new opportunity for Spinal Muscular Atrophy therapies. Biochem Soc Trans 2024; 52:465-479. [PMID: 38391004 PMCID: PMC10903476 DOI: 10.1042/bst20231116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/12/2024] [Accepted: 02/13/2024] [Indexed: 02/24/2024]
Abstract
The underlying cause of Spinal Muscular Atrophy (SMA) is in the reduction of survival motor neuron (SMN) protein levels due to mutations in the SMN1 gene. The specific effects of SMN protein loss and the resulting pathological alterations are not fully understood. Given the crucial roles of the SMN protein in snRNP biogenesis and its interactions with ribosomes and translation-related proteins and mRNAs, a decrease in SMN levels below a specific threshold in SMA is expected to affect translational control of gene expression. This review covers both direct and indirect SMN interactions across various translation-related cellular compartments and processes, spanning from ribosome biogenesis to local translation and beyond. Additionally, it aims to outline deficiencies and alterations in translation observed in SMA models and patients, while also discussing the implications of the relationship between SMN protein and the translation machinery within the context of current and future therapies.
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Liang J, Cai D. Membrane-less compartments in the nucleus: Separated or connected phases? Curr Opin Cell Biol 2023; 84:102215. [PMID: 37574634 PMCID: PMC10528681 DOI: 10.1016/j.ceb.2023.102215] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 07/14/2023] [Accepted: 07/17/2023] [Indexed: 08/15/2023]
Abstract
In recent years, it has become increasingly clear that many nuclear membrane-less compartments have liquid-like properties and may form through the physicochemical process of phase separation. In this review, we will first discuss how various nuclear compartments, such as the genome, transcription compartments, and nuclear bodies are formed through phase separation. Then, we propose that inter-compartmental communications can also be prevalent and may be mediated by inter-compartmental diffusion of macromolecules, fusion among different compartments, and transient or stable contacts among nuclear compartments. Understanding how nuclear compartments communicate with each other represents an exciting new area of research and may reveal important insights about cellular functions and uncover previously under-appreciated disease mechanisms.
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Affiliation(s)
- Jindayi Liang
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Danfeng Cai
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA; Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
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Jevtic Z, Allram M, Grebien F, Schwaller J. Biomolecular Condensates in Myeloid Leukemia: What Do They Tell Us? Hemasphere 2023; 7:e923. [PMID: 37388925 PMCID: PMC10306439 DOI: 10.1097/hs9.0000000000000923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 05/31/2023] [Indexed: 07/01/2023] Open
Abstract
Recent studies have suggested that several oncogenic and tumor-suppressive proteins carry out their functions in the context of specific membrane-less cellular compartments. As these compartments, generally referred to as onco-condensates, are specific to tumor cells and are tightly linked to disease development, the mechanisms of their formation and maintenance have been intensively studied. Here we review the proposed leukemogenic and tumor-suppressive activities of nuclear biomolecular condensates in acute myeloid leukemia (AML). We focus on condensates formed by oncogenic fusion proteins including nucleoporin 98 (NUP98), mixed-lineage leukemia 1 (MLL1, also known as KMT2A), mutated nucleophosmin (NPM1c) and others. We also discuss how altered condensate formation contributes to malignant transformation of hematopoietic cells, as described for promyelocytic leukemia protein (PML) in PML::RARA-driven acute promyelocytic leukemia (APL) and other myeloid malignancies. Finally, we discuss potential strategies for interfering with the molecular mechanisms related to AML-associated biomolecular condensates, as well as current limitations of the field.
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Affiliation(s)
- Zivojin Jevtic
- Department of Biomedicine (DBM), University Children’s Hospital Basel, University of Basel, Switzerland
| | - Melanie Allram
- Institute for Medical Biochemistry, University of Veterinary Medicine, Vienna, Austria
| | - Florian Grebien
- Institute for Medical Biochemistry, University of Veterinary Medicine, Vienna, Austria
- St. Anna Children’s Cancer Research Institute (CCRI), Vienna, Austria
| | - Juerg Schwaller
- Department of Biomedicine (DBM), University Children’s Hospital Basel, University of Basel, Switzerland
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Lee YRJ, Yamada S, Lo SH. Phase transition of tensin-1 during the focal adhesion disassembly and cell division. Proc Natl Acad Sci U S A 2023; 120:e2303037120. [PMID: 37011205 PMCID: PMC10104483 DOI: 10.1073/pnas.2303037120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 03/09/2023] [Indexed: 04/05/2023] Open
Abstract
Biomolecular condensates are nonmembranous structures that are mainly formed through liquid-liquid phase separation. Tensins are focal adhesion (FA) proteins linking the actin cytoskeleton to integrin receptors. Here, we report that GFP-tagged tensin-1 (TNS1) proteins phase-separate to form biomolecular condensates in cells. Live-cell imaging showed that new TNS1 condensates are budding from the disassembling ends of FAs, and the presence of these condensates is cell cycle dependent. TNS1 condensates dissolve immediately prior to mitosis and rapidly reappear while postmitotic daughter cells establish new FAs. TNS1 condensates contain selected FA proteins and signaling molecules such as pT308Akt but not pS473Akt, suggesting previously unknown roles of TNS1 condensates in disassembling FAs, as the storage of core FA components and the signaling intermediates.
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Affiliation(s)
- Yuh-Ru Julie Lee
- Department of Plant Biology, University of California, Davis, CA95616
| | - Soichiro Yamada
- Department of Biomedical Engineering, University of California, Davis, CA95616
| | - Su Hao Lo
- Department of Biochemistry and Molecular Medicine, University of California, Davis, CA95817
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Liu Z, Yethiraj A, Cui Q. Sensitive and selective polymer condensation at membrane surface driven by positive co-operativity. Proc Natl Acad Sci U S A 2023; 120:e2212516120. [PMID: 37018196 PMCID: PMC10104518 DOI: 10.1073/pnas.2212516120] [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: 07/20/2022] [Accepted: 03/06/2023] [Indexed: 04/06/2023] Open
Abstract
Biomolecular phase separation has emerged as an essential mechanism for cellular organization. How cells respond to environmental stimuli in a robust and sensitive manner to build functional condensates at the proper time and location is only starting to be understood. Recently, lipid membranes have been recognized as an important regulatory center for biomolecular condensation. However, how the interplay between the phase behaviors of cellular membranes and surface biopolymers may contribute to the regulation of surface condensation remains to be elucidated. Using simulations and a mean-field theoretical model, we show that two key factors are the membrane's tendency to phase-separate and the surface polymer's ability to reorganize local membrane composition. Surface condensate forms with high sensitivity and selectivity in response to features of biopolymer when positive co-operativity is established between coupled growth of the condensate and local lipid domains. This effect relating the degree of membrane-surface polymer co-operativity and condensate property regulation is shown to be robust by different ways of tuning the co-operativity, such as varying membrane protein obstacle concentration, lipid composition, and the affinity between lipid and polymer. The general physical principle emerged from the current analysis may have implications in other biological processes and beyond.
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Affiliation(s)
- Zhuang Liu
- Department of Physics, Boston University, Boston, MA02215
| | - Arun Yethiraj
- Department of Chemistry, University of Wisconsin, Madison, WI53706
| | - Qiang Cui
- Department of Physics, Boston University, Boston, MA02215
- Department of Chemistry, Boston University, Boston, MA02215
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Decle-Carrasco S, Rodríguez-Piña AL, Rodríguez-Zapata LC, Castano E. Current research on viral proteins that interact with fibrillarin. Mol Biol Rep 2023; 50:4631-4643. [PMID: 36928641 PMCID: PMC10018631 DOI: 10.1007/s11033-023-08343-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/15/2023] [Indexed: 03/18/2023]
Abstract
The nucleolus is a multifunctional nuclear domain primarily dedicated to ribosome biogenesis. Certain viruses developed strategies to manipulate host nucleolar proteins to facilitate their replication by modulating ribosomal RNA (rRNA) processing. This association interferes with nucleolar functions resulting in overactivation or arrest of ribosome biogenesis, induction or inhibition of apoptosis, and affecting stress response. The nucleolar protein fibrillarin (FBL) is an important target of some plant and animal viruses. FBL is an essential and highly conserved S-adenosyl methionine (SAM) dependent methyltransferase, capable of rRNA degradation by its intrinsically disordered region (IDR), the glycine/arginine-rich (GAR) domain. It forms a ribonucleoprotein complex that directs 2'-O-methylations in more than 100 sites of pre-rRNAs. It is involved in multiple cellular processes, including initiation of transcription, oncogenesis, and apoptosis, among others. The interaction with animal viruses, including human viruses, triggered its redistribution to the nucleoplasm and cytoplasm, interfering with its role in pre-rRNA processing. Viral-encoded proteins with IDRs as nucleocapsids, matrix, Tat protein, and even a viral snoRNA, can associate with FBL, forcing the nucleolar protein to undergo atypical functions. Here we review the molecular mechanisms employed by animal and human viruses to usurp FBL functions and the effect on cellular processes, particularly in ribosome biogenesis.
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Affiliation(s)
- Stefano Decle-Carrasco
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Alma Laura Rodríguez-Piña
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Luis Carlos Rodríguez-Zapata
- Unidad de Biotecnología. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Enrique Castano
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México.
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Klimešová K, Petržílková H, Bařinka C, Staněk D. SART3 associates with a post-splicing complex. J Cell Sci 2023; 136:jcs260380. [PMID: 36620952 DOI: 10.1242/jcs.260380] [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: 06/27/2022] [Accepted: 12/10/2022] [Indexed: 01/10/2023] Open
Abstract
SART3 is a multifunctional protein that acts in several steps of gene expression, including assembly and recycling of the spliceosomal U4/U6 small nuclear ribonucleoprotein particle (snRNP). In this work, we provide evidence that SART3 associates via its N-terminal HAT domain with the 12S U2 snRNP. Further analysis showed that SART3 associates with the post-splicing complex containing U2 and U5 snRNP components. In addition, we observed an interaction between SART3 and the RNA helicase DHX15, which disassembles post-splicing complexes. Based on our data, we propose a model that SART3 associates via its N-terminal HAT domain with the post-splicing complex, where it interacts with U6 snRNA to protect it and to initiate U6 snRNA recycling before a next round of splicing.
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MESH Headings
- RNA Splicing/genetics
- Spliceosomes/genetics
- Spliceosomes/metabolism
- RNA, Small Nuclear/genetics
- RNA, Small Nuclear/metabolism
- Ribonucleoprotein, U4-U6 Small Nuclear/genetics
- Ribonucleoprotein, U4-U6 Small Nuclear/metabolism
- Ribonucleoprotein, U5 Small Nuclear/genetics
- Ribonucleoprotein, U5 Small Nuclear/metabolism
- Ribonucleoprotein, U2 Small Nuclear/genetics
- Ribonucleoprotein, U2 Small Nuclear/metabolism
- Ribonucleoproteins, Small Nuclear/genetics
- Ribonucleoproteins, Small Nuclear/metabolism
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Affiliation(s)
- Klára Klimešová
- Department of RNA Biology, Institute of Molecular Genetics, Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Hana Petržílková
- Department of RNA Biology, Institute of Molecular Genetics, Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Cyril Bařinka
- Laboratory of Structural Biology, Institute of Biotechnology, Czech Academy of Sciences, 252 50 Prague, Czech Republic
| | - David Staněk
- Department of RNA Biology, Institute of Molecular Genetics, Czech Academy of Sciences, 142 20 Prague, Czech Republic
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Liu W, Samanta A, Deng J, Akintayo CO, Walther A. Mechanistic Insights into the Phase Separation Behavior and Pathway-Directed Information Exchange in all-DNA Droplets. Angew Chem Int Ed Engl 2022; 61:e202208951. [PMID: 36112754 PMCID: PMC9828218 DOI: 10.1002/anie.202208951] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Indexed: 01/12/2023]
Abstract
Liquid-liquid phase separation provides a versatile approach to fabricating cell-mimicking coacervates. Recently, it was discovered that phase separation of single-stranded DNA (ssDNA) allows for forming protocells and microgels in multicomponent systems. However, the mechanism of the ssDNA phase separation is not comprehensively understood. Here, we present mechanistic insights into the metal-dependent phase separation of ssDNA and leverage this understanding for a straightforward formation of all-DNA droplets. Two phase separation temperatures are found that correspond to the formation of primary nuclei and a growth process. Ca2+ allows for irreversible, whereas Mg2+ leads to reversible phase separation. Capitalizing on these differences makes it possible to control the information transfer of one-component DNA droplets and two-component core-shell protocells. This study introduces new kinetic traps of phase separating ssDNA that lead to new phenomena in cell-mimicking systems.
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Affiliation(s)
- Wei Liu
- Life-Like Materials and Systems, Department of ChemistryUniversity of MainzDuesbergweg 10–1455128MainzGermany
| | - Avik Samanta
- Life-Like Materials and Systems, Department of ChemistryUniversity of MainzDuesbergweg 10–1455128MainzGermany
| | - Jie Deng
- Life-Like Materials and Systems, Department of ChemistryUniversity of MainzDuesbergweg 10–1455128MainzGermany,Present address: Department of Cancer BiologyDana-Farber Cancer Institute and Wyss Institute for Biologically Inspired EngineeringHarvard Medical SchoolBostonMA 02115USA
| | - Cecilia Oluwadunsin Akintayo
- Life-Like Materials and Systems, Department of ChemistryUniversity of MainzDuesbergweg 10–1455128MainzGermany,Cluster of Excellence livMatS @ FIT—Freiburg Center for Interactive Materials and Bioinspired TechnologiesUniversity of FreiburgGeorges-Köhler-Allee 10579110FreiburgGermany
| | - Andreas Walther
- Life-Like Materials and Systems, Department of ChemistryUniversity of MainzDuesbergweg 10–1455128MainzGermany,Cluster of Excellence livMatS @ FIT—Freiburg Center for Interactive Materials and Bioinspired TechnologiesUniversity of FreiburgGeorges-Köhler-Allee 10579110FreiburgGermany
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14
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Courchaine E, Gelles-Watnick S, Machyna M, Straube K, Sauyet S, Enright J, Neugebauer KM. The coilin N-terminus mediates multivalent interactions between coilin and Nopp140 to form and maintain Cajal bodies. Nat Commun 2022; 13:6005. [PMID: 36224177 PMCID: PMC9556525 DOI: 10.1038/s41467-022-33434-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 09/16/2022] [Indexed: 11/25/2022] Open
Abstract
Cajal bodies (CBs) are ubiquitous nuclear membraneless organelles (MLOs) that concentrate and promote efficient biogenesis of snRNA-protein complexes involved in splicing (snRNPs). Depletion of the CB scaffolding protein coilin disperses snRNPs, making CBs a model system for studying the structure and function of MLOs. Although it is assumed that CBs form through condensation, the biomolecular interactions responsible remain elusive. Here, we discover the unexpected capacity of coilin’s N-terminal domain (NTD) to form extensive fibrils in the cytoplasm and discrete nuclear puncta in vivo. Single amino acid mutational analysis reveals distinct molecular interactions between coilin NTD proteins to form fibrils and additional NTD interactions with the nuclear Nopp140 protein to form puncta. We provide evidence that Nopp140 has condensation capacity and is required for CB assembly. From these observations, we propose a model in which coilin NTD–NTD mediated assemblies make multivalent contacts with Nopp140 to achieve biomolecular condensation in the nucleus. Cajal bodies are membraneless organelles scaffolded by coilin protein. Here, coilin–coilin and coilin–Nopp140 interaction sites are identified and perturbed, revealing coilin’s capacity to form long fibrils and be remodeled into spherical structures.
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Affiliation(s)
- Edward Courchaine
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Sara Gelles-Watnick
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Martin Machyna
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Korinna Straube
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Sarah Sauyet
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Jade Enright
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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15
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Ng WS, Sielaff H, Zhao ZW. Phase Separation-Mediated Chromatin Organization and Dynamics: From Imaging-Based Quantitative Characterizations to Functional Implications. Int J Mol Sci 2022; 23:8039. [PMID: 35887384 PMCID: PMC9316379 DOI: 10.3390/ijms23148039] [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: 06/20/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 12/14/2022] Open
Abstract
As an effective and versatile strategy to compartmentalize cellular components without the need for lipid membranes, phase separation has been found to underpin a wide range of intranuclear processes, particularly those involving chromatin. Many of the unique physico-chemical properties of chromatin-based phase condensates are harnessed by the cell to accomplish complex regulatory functions in a spatially and temporally controlled manner. Here, we survey key recent findings on the mechanistic roles of phase separation in regulating the organization and dynamics of chromatin-based molecular processes across length scales, packing states and intranuclear functions, with a particular emphasis on quantitative characterizations of these condensates enabled by advanced imaging-based approaches. By illuminating the complex interplay between chromatin and various chromatin-interacting molecular species mediated by phase separation, this review sheds light on an emerging multi-scale, multi-modal and multi-faceted landscape that hierarchically regulates the genome within the highly crowded and dynamic nuclear space. Moreover, deficiencies in existing studies also highlight the need for mechanism-specific criteria and multi-parametric approaches for the characterization of chromatin-based phase separation using complementary techniques and call for greater efforts to correlate the quantitative features of these condensates with their functional consequences in close-to-native cellular contexts.
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Affiliation(s)
- Woei Shyuan Ng
- Department of Chemistry, Faculty of Science, National University of Singapore, Singapore 119543, Singapore; (W.S.N.); (H.S.)
- Centre for BioImaging Sciences (CBIS), Faculty of Science, National University of Singapore, Singapore 117557, Singapore
| | - Hendrik Sielaff
- Department of Chemistry, Faculty of Science, National University of Singapore, Singapore 119543, Singapore; (W.S.N.); (H.S.)
- Centre for BioImaging Sciences (CBIS), Faculty of Science, National University of Singapore, Singapore 117557, Singapore
| | - Ziqing Winston Zhao
- Department of Chemistry, Faculty of Science, National University of Singapore, Singapore 119543, Singapore; (W.S.N.); (H.S.)
- Centre for BioImaging Sciences (CBIS), Faculty of Science, National University of Singapore, Singapore 117557, Singapore
- Mechanobiology Institute (MBI), National University of Singapore, Singapore 117411, Singapore
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16
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Liquid-liquid phase separation in tumor biology. Signal Transduct Target Ther 2022; 7:221. [PMID: 35803926 PMCID: PMC9270353 DOI: 10.1038/s41392-022-01076-x] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/16/2022] [Accepted: 06/21/2022] [Indexed: 12/12/2022] Open
Abstract
Liquid–liquid phase separation (LLPS) is a novel principle for explaining the precise spatial and temporal regulation in living cells. LLPS compartmentalizes proteins and nucleic acids into micron-scale, liquid-like, membraneless bodies with specific functions, which were recently termed biomolecular condensates. Biomolecular condensates are executors underlying the intracellular spatiotemporal coordination of various biological activities, including chromatin organization, genomic stability, DNA damage response and repair, transcription, and signal transduction. Dysregulation of these cellular processes is a key event in the initiation and/or evolution of cancer, and emerging evidence has linked the formation and regulation of LLPS to malignant transformations in tumor biology. In this review, we comprehensively summarize the detailed mechanisms of biomolecular condensate formation and biophysical function and review the recent major advances toward elucidating the multiple mechanisms involved in cancer cell pathology driven by aberrant LLPS. In addition, we discuss the therapeutic perspectives of LLPS in cancer research and the most recently developed drug candidates targeting LLPS modulation that can be used to combat tumorigenesis.
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17
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Maccaroni K, La Torre M, Burla R, Saggio I. Phase Separation in the Nucleus and at the Nuclear Periphery during Post-Mitotic Nuclear Envelope Reformation. Cells 2022; 11:1749. [PMID: 35681444 PMCID: PMC9179440 DOI: 10.3390/cells11111749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/24/2022] [Accepted: 05/24/2022] [Indexed: 02/04/2023] Open
Abstract
Membrane-enclosed organelle compartmentalization is not the only way by which cell processes are spatially organized. Phase separation is emerging as a new driver in the organization of membrane-less compartments and biological processes. Liquid-liquid phase separation has been indicated as a new way to control the kinetics of molecular reactions and is based on weak multivalent interactions affecting the stoichiometry of the molecules involved. In the nucleus, liquid-liquid phase separation may represent an ancestral means of controlling genomic activity by forming discrete chromatin regions, regulating transcriptional activity, contributing to the assembly of DNA damage response foci, and controlling the organization of chromosomes. Liquid-liquid phase separation also contributes to chromatin function through its role in the reorganization of the nuclear periphery in the post-mitotic phase. Herein, we describe the basic principles regulating liquid-liquid phase separation, analyze examples of phase separation occurring in the nucleus, and dedicate attention to the implication of liquid-liquid phase separation in the reorganization of the nuclear periphery by the endosomal sorting complexes required for transport (ESCRT) machinery. Although some caution is warranted, current scientific knowledge allows for the hypothesis that many factors and processes in the cell are yet to be discovered which are functionally associated with phase separation.
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Affiliation(s)
- Klizia Maccaroni
- Department of Biology and Biotechnology, Sapienza University, 00185 Rome, Italy; (K.M.); (M.L.T.); (R.B.)
| | - Mattia La Torre
- Department of Biology and Biotechnology, Sapienza University, 00185 Rome, Italy; (K.M.); (M.L.T.); (R.B.)
| | - Romina Burla
- Department of Biology and Biotechnology, Sapienza University, 00185 Rome, Italy; (K.M.); (M.L.T.); (R.B.)
- CNR Institute of Molecular Biology and Pathology, 00185 Rome, Italy
| | - Isabella Saggio
- Department of Biology and Biotechnology, Sapienza University, 00185 Rome, Italy; (K.M.); (M.L.T.); (R.B.)
- CNR Institute of Molecular Biology and Pathology, 00185 Rome, Italy
- Institute of Structural Biology, Nanyang Technological University, Singapore 639798, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore 639798, Singapore
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18
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Caparco AA, Dautel DR, Champion JA. Protein Mediated Enzyme Immobilization. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2106425. [PMID: 35182030 DOI: 10.1002/smll.202106425] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 12/22/2021] [Indexed: 06/14/2023]
Abstract
Enzyme immobilization is an essential technology for commercializing biocatalysis. It imparts stability, recoverability, and other valuable features that improve the effectiveness of biocatalysts. While many avenues to join an enzyme to solid phases exist, protein-mediated immobilization is rapidly developing and has many advantages. Protein-mediated immobilization allows for the binding interaction to be genetically coded, can be used to create artificial multienzyme cascades, and enables modular designs that expand the variety of enzymes immobilized. By designing around binding interactions between protein domains, they can be integrated into functional materials for protein immobilization. These materials are framed within the context of biocatalytic performance, immobilization efficiency, and stability of the materials. In this review, supports composed entirely of protein are discussed first, with systems such as cellulosomes and protein cages being discussed alongside newer technologies like spore-based biocatalysts and forizymes. Protein-composite materials such as polymersomes and protein-inorganic supraparticles are then discussed to demonstrate how protein-mediated strategies are applied to many classes of solid materials. Critical analysis and future directions of protein-based immobilization are then discussed, with a particular focus on both computational and design strategies to advance this area of research and make it more broadly applicable to many classes of enzymes.
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Affiliation(s)
- Adam A Caparco
- Department of Nanoengineering, University of California, San Diego, MC 0448, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Dylan R Dautel
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 950 Atlantic Drive NW, Atlanta, GA, 30332, USA
| | - Julie A Champion
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 950 Atlantic Drive NW, Atlanta, GA, 30332, USA
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19
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Rota IA, Handel AE, Maio S, Klein F, Dhalla F, Deadman ME, Cheuk S, Newman JA, Michaels YS, Zuklys S, Prevot N, Hublitz P, Charles PD, Gkazi AS, Adamopoulou E, Qasim W, Davies EG, Hanson I, Pagnamenta AT, Camps C, Dreau HM, White A, James K, Fischer R, Gileadi O, Taylor JC, Fulga T, Lagerholm BC, Anderson G, Sezgin E, Holländer GA. FOXN1 forms higher-order nuclear condensates displaced by mutations causing immunodeficiency. SCIENCE ADVANCES 2021; 7:eabj9247. [PMID: 34860543 PMCID: PMC8641933 DOI: 10.1126/sciadv.abj9247] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 10/15/2021] [Indexed: 05/04/2023]
Abstract
The transcription factor FOXN1 is a master regulator of thymic epithelial cell (TEC) development and function. Here, we demonstrate that FOXN1 expression is differentially regulated during organogenesis and participates in multimolecular nuclear condensates essential for the factor’s transcriptional activity. FOXN1’s C-terminal sequence regulates the diffusion velocity within these aggregates and modulates the binding to proximal gene regulatory regions. These dynamics are altered in a patient with a mutant FOXN1 that is modified in its C-terminal sequence. This mutant is transcriptionally inactive and acts as a dominant negative factor displacing wild-type FOXN1 from condensates and causing athymia and severe lymphopenia in heterozygotes. Expression of the mutated mouse ortholog selectively impairs mouse TEC differentiation, revealing a gene dose dependency for individual TEC subtypes. We have therefore identified the cause for a primary immunodeficiency disease and determined the mechanism by which this FOXN1 gain-of-function mutant mediates its dominant negative effect.
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Affiliation(s)
- Ioanna A. Rota
- Department of Paediatrics and the MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Adam E. Handel
- Department of Paediatrics and the MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Stefano Maio
- Department of Paediatrics and the MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Fabian Klein
- Department of Paediatrics and the MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Fatima Dhalla
- Department of Paediatrics and the MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Mary E. Deadman
- Department of Paediatrics and the MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Stanley Cheuk
- Department of Paediatrics and the MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Joseph A. Newman
- Structural Genomics Consortium, University of Oxford, ORCRB, Roosevelt Drive, Oxford, UK
| | - Yale S. Michaels
- Genome Engineering and Synthetic Biology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Saulius Zuklys
- Paediatric Immunology, Department of Biomedicine, University of Basel and University Children’s Hospital Basel, Basel, Switzerland
| | - Nicolas Prevot
- Department of Paediatrics and the MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Philip Hublitz
- MRC Weatherall Institute of Molecular Medicine, Genome engineering services, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Philip D. Charles
- Target Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK
| | - Athina Soragia Gkazi
- Great Ormond Street Hospital and Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Eleni Adamopoulou
- Department of Paediatrics and the MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Waseem Qasim
- Great Ormond Street Hospital and Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Edward Graham Davies
- Great Ormond Street Hospital and Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Imelda Hanson
- Department of Pediatrics, Section of Pediatric Immunology, Allergy, and Retrovirology, Baylor College of Medicine, Houston, TX, USA
| | - Alistair T. Pagnamenta
- National Institute for Health Research Biomedical Research Centre, Oxford, UK
- Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Carme Camps
- National Institute for Health Research Biomedical Research Centre, Oxford, UK
- Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Helene M. Dreau
- Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK
| | - Andrea White
- Institute for Immunology and Immunotherapy, Medical School, University of Birmingham, Birmingham B15 2TT, UK
| | - Kieran James
- Institute for Immunology and Immunotherapy, Medical School, University of Birmingham, Birmingham B15 2TT, UK
| | - Roman Fischer
- Target Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK
| | - Opher Gileadi
- Structural Genomics Consortium, University of Oxford, ORCRB, Roosevelt Drive, Oxford, UK
| | - Jenny C. Taylor
- National Institute for Health Research Biomedical Research Centre, Oxford, UK
- Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Tudor Fulga
- Genome Engineering and Synthetic Biology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - B. Christoffer Lagerholm
- Wolfson Imaging Centre Oxford, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford OX3 9DS, UK
| | - Graham Anderson
- Institute for Immunology and Immunotherapy, Medical School, University of Birmingham, Birmingham B15 2TT, UK
| | - Erdinc Sezgin
- Paediatric Immunology, Department of Biomedicine, University of Basel and University Children’s Hospital Basel, Basel, Switzerland
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Georg A. Holländer
- Department of Paediatrics and the MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- Paediatric Immunology, Department of Biomedicine, University of Basel and University Children’s Hospital Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
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20
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Yu X, Zhang L, Shen J, Zhai Y, Jiang Q, Yi M, Deng X, Ruan Z, Fang R, Chen Z, Ning X, Jiang Z. The STING phase-separator suppresses innate immune signalling. Nat Cell Biol 2021; 23:330-340. [PMID: 33833429 DOI: 10.1038/s41556-021-00659-0] [Citation(s) in RCA: 94] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 03/02/2021] [Indexed: 02/01/2023]
Abstract
Biomolecular condensates (biocondensates) formed via liquid-liquid phase-separation of soluble proteins have been studied extensively. However, neither the phase-separation of endoplasmic reticulum (ER) transmembrane protein nor a biocondensate with organized membranous structures has been reported. Here, we have discovered a spherical ER membranous biocondensate with puzzle-like structures caused by condensation of the ER-resident stimulator of interferon genes (STING) in DNA virus-infected or 2'3'-cGAMP (cyclic GMP-AMP)-treated cells, which required STING transmembrane domains, an intrinsically disordered region (IDR) and a dimerization domain. Intracellular 2'3'-cGAMP concentrations determined STING translocation or condensation. STING biocondensates constrained STING and TBK1 (TANK binding protein 1) to prevent innate immunity from overactivation, presumably acting like a 'STING-TBK1-cGAMP sponge'. Cells expressing STING-E336G/E337G showed notably enhanced innate immune responses due to impaired STING condensation after viral infection at later stages. Microtubule inhibitors impeded the STING condensate gel-like transition and augmented type I-interferon production in DNA virus-infected cells. This membranous biocondensate was therefore named the STING phase-separator.
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Affiliation(s)
- Xiaoyu Yu
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Liyuan Zhang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Jingxiang Shen
- Center for Quantitative Biology, Peking University, Beijing, China
| | - Yanfang Zhai
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Qifei Jiang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Mengran Yi
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Xiaobing Deng
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Ziran Ruan
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Run Fang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Zhaolong Chen
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking University, Beijing, China
| | - Xiaohan Ning
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Zhengfan Jiang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking University, Beijing, China. .,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China.
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21
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Campillo-Marcos I, García-González R, Navarro-Carrasco E, Lazo PA. The human VRK1 chromatin kinase in cancer biology. Cancer Lett 2021; 503:117-128. [PMID: 33516791 DOI: 10.1016/j.canlet.2020.12.032] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 11/30/2020] [Accepted: 12/21/2020] [Indexed: 01/08/2023]
Abstract
VRK1 is a nuclear Ser-Thr chromatin kinase that does not mutate in cancer, and is overexpressed in many types of tumors and associated with a poor prognosis. Chromatin VRK1 phosphorylates several transcription factors, including p53, histones and proteins implicated in DNA damage response pathways. In the context of cell proliferation, VRK1 regulates entry in cell cycle, chromatin condensation in G2/M, Golgi fragmentation, Cajal body dynamics and nuclear envelope assembly in mitosis. This kinase also controls the initial chromatin relaxation associated with histone acetylation, and the non-homologous-end joining (NHEJ) DNA repair pathway, which involves sequential steps such as γH2AX, NBS1 and 53BP1 foci formation, all phosphorylated by VRK1, in response to ionizing radiation or chemotherapy. In addition, VRK1 can be an alternative target for therapies based on synthetic lethality strategies. Therefore, VRK1 roles on proliferation have a pro-tumorigenic effect. Functions regulating chromatin stability and DNA damage responses have a protective anti-tumor role in normal cells, but in tumor cells can also facilitate resistance to genotoxic treatments.
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Affiliation(s)
- Ignacio Campillo-Marcos
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular Del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Salamanca, 37007 Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, 37007 Salamanca, Spain.
| | - Raúl García-González
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular Del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Salamanca, 37007 Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, 37007 Salamanca, Spain.
| | - Elena Navarro-Carrasco
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular Del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Salamanca, 37007 Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, 37007 Salamanca, Spain.
| | - Pedro A Lazo
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular Del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Salamanca, 37007 Salamanca, Spain.
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22
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Christy ATR, Kusumaatmaja H, Miller MA. Control of Superselectivity by Crowding in Three-Dimensional Hosts. PHYSICAL REVIEW LETTERS 2021; 126:028002. [PMID: 33512214 DOI: 10.1103/physrevlett.126.028002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 12/09/2020] [Indexed: 06/12/2023]
Abstract
Motivated by the fine compositional control observed in membraneless droplet organelles in cells, we investigate how a sharp binding-unbinding transition can occur between multivalent client molecules and receptors embedded in a porous three-dimensional structure. In contrast to similar superselective binding previously observed at surfaces, we have identified that a key effect in a three-dimensional environment is that the presence of inert crowding agents can significantly enhance or even introduce superselectivity. In essence, molecular crowding initially suppresses binding via an entropic penalty, but the clients can then more easily form many bonds simultaneously. We demonstrate the robustness of the superselective behavior with respect to client valency, linker length, and binding interactions in Monte Carlo simulations of an archetypal lattice polymer model.
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Affiliation(s)
- Andrew T R Christy
- Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | - Halim Kusumaatmaja
- Department of Physics, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | - Mark A Miller
- Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom
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23
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Wotherspoon D, Rogerson C, O’Shaughnessy RF. Perspective: Controlling Epidermal Terminal Differentiation with Transcriptional Bursting and RNA Bodies. J Dev Biol 2020; 8:E29. [PMID: 33291764 PMCID: PMC7768391 DOI: 10.3390/jdb8040029] [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: 10/23/2020] [Revised: 11/20/2020] [Accepted: 12/02/2020] [Indexed: 12/21/2022] Open
Abstract
The outer layer of the skin, the epidermis, is the principal barrier to the external environment: post-mitotic cells terminally differentiate to form a tough outer cornified layer of enucleate and flattened cells that confer the majority of skin barrier function. Nuclear degradation is required for correct cornified envelope formation. This process requires mRNA translation during the process of nuclear destruction. In this review and perspective, we address the biology of transcriptional bursting and the formation of ribonuclear particles in model organisms including mammals, and then examine the evidence that these phenomena occur as part of epidermal terminal differentiation.
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Affiliation(s)
- Duncan Wotherspoon
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Queen Mary University of London, London E1 2AT, UK;
| | | | - Ryan F.L. O’Shaughnessy
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Queen Mary University of London, London E1 2AT, UK;
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24
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Song D, Jo Y, Choi JM, Jung Y. Client proximity enhancement inside cellular membrane-less compartments governed by client-compartment interactions. Nat Commun 2020; 11:5642. [PMID: 33159068 PMCID: PMC7648067 DOI: 10.1038/s41467-020-19476-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 10/16/2020] [Indexed: 01/17/2023] Open
Abstract
Membrane-less organelles or compartments are considered to be dynamic reaction centers for spatiotemporal control of diverse cellular processes in eukaryotic cells. Although their formation mechanisms have been steadily elucidated via the classical concept of liquid-liquid phase separation, biomolecular behaviors such as protein interactions inside these liquid compartments have been largely unexplored. Here we report quantitative measurements of changes in protein interactions for the proteins recruited into membrane-less compartments (termed client proteins) in living cells. Under a wide range of phase separation conditions, protein interaction signals were vastly increased only inside compartments, indicating greatly enhanced proximity between recruited client proteins. By employing an in vitro phase separation model, we discovered that the operational proximity of clients (measured from client-client interactions) could be over 16 times higher than the expected proximity from actual client concentrations inside compartments. We propose that two aspects should be considered when explaining client proximity enhancement by phase separation compartmentalization: (1) clients are selectively recruited into compartments, leading to concentration enrichment, and more importantly, (2) recruited clients are further localized around compartment-forming scaffold protein networks, which results in even higher client proximity.
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Affiliation(s)
- Daesun Song
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Yongsang Jo
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Jeong-Mo Choi
- Natural Science Research Institute, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
- Department of Chemistry, Pusan National University, Busan, 46241, Republic of Korea
| | - Yongwon Jung
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
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25
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Sheng J, Olrichs NK, Gadella BM, Kaloyanova DV, Helms JB. Regulation of Functional Protein Aggregation by Multiple Factors: Implications for the Amyloidogenic Behavior of the CAP Superfamily Proteins. Int J Mol Sci 2020; 21:E6530. [PMID: 32906672 PMCID: PMC7554809 DOI: 10.3390/ijms21186530] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/01/2020] [Accepted: 09/03/2020] [Indexed: 12/13/2022] Open
Abstract
The idea that amyloid fibrils and other types of protein aggregates are toxic for cells has been challenged by the discovery of a variety of functional aggregates. However, an identification of crucial differences between pathological and functional aggregation remains to be explored. Functional protein aggregation is often reversible by nature in order to respond properly to changing physiological conditions of the cell. In addition, increasing evidence indicates that fast fibril growth is a feature of functional amyloids, providing protection against the long-term existence of potentially toxic oligomeric intermediates. It is becoming clear that functional protein aggregation is a complexly organized process that can be mediated by a multitude of biomolecular factors. In this overview, we discuss the roles of diverse biomolecules, such as lipids/membranes, glycosaminoglycans, nucleic acids and metal ions, in regulating functional protein aggregation. Our studies on the protein GAPR-1 revealed that several of these factors influence the amyloidogenic properties of this protein. These observations suggest that GAPR-1, as well as the cysteine-rich secretory proteins, antigen 5 and pathogenesis-related proteins group 1 (CAP) superfamily of proteins that it belongs to, require the assembly into an amyloid state to exert several of their functions. A better understanding of functional aggregate formation may also help in the prevention and treatment of amyloid-related diseases.
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Affiliation(s)
| | | | | | | | - J. Bernd Helms
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands; (J.S.); (N.K.O.); (B.M.G.); (D.V.K.)
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26
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Hasenson SE, Shav‐Tal Y. Speculating on the Roles of Nuclear Speckles: How RNA‐Protein Nuclear Assemblies Affect Gene Expression. Bioessays 2020; 42:e2000104. [DOI: 10.1002/bies.202000104] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/17/2020] [Indexed: 02/06/2023]
Affiliation(s)
- Sarah E. Hasenson
- The Mina & Everard Goodman Faculty of Life Sciences and the Institute of Nanotechnology and Advanced Materials Bar‐Ilan University Ramat Gan 4481400 Israel
| | - Yaron Shav‐Tal
- The Mina & Everard Goodman Faculty of Life Sciences and the Institute of Nanotechnology and Advanced Materials Bar‐Ilan University Ramat Gan 4481400 Israel
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27
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Rigidity enhances a magic-number effect in polymer phase separation. Nat Commun 2020; 11:1561. [PMID: 32214099 PMCID: PMC7096466 DOI: 10.1038/s41467-020-15395-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Accepted: 03/03/2020] [Indexed: 12/19/2022] Open
Abstract
Cells possess non-membrane-bound bodies, many of which are now understood as phase-separated condensates. One class of such condensates is composed of two polymer species, where each consists of repeated binding sites that interact in a one-to-one fashion with the binding sites of the other polymer. Biologically-motivated modeling revealed that phase separation is suppressed by a "magic-number effect" which occurs if the two polymers can form fully-bonded small oligomers by virtue of the number of binding sites in one polymer being an integer multiple of the number of binding sites of the other. Here we use lattice-model simulations and analytical calculations to show that this magic-number effect can be greatly enhanced if one of the polymer species has a rigid shape that allows for multiple distinct bonding conformations. Moreover, if one species is rigid, the effect is robust over a much greater range of relative concentrations of the two species.
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28
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Martín-Doncel E, Rojas AM, Cantarero L, Lazo PA. VRK1 functional insufficiency due to alterations in protein stability or kinase activity of human VRK1 pathogenic variants implicated in neuromotor syndromes. Sci Rep 2019; 9:13381. [PMID: 31527692 PMCID: PMC6746721 DOI: 10.1038/s41598-019-49821-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 08/30/2019] [Indexed: 12/12/2022] Open
Abstract
Very rare polymorphisms in the human VRK1 (vaccinia-related kinase 1) gene have been identified in complex neuromotor phenotypes associated to spinal muscular atrophy (SMA), pontocerebellar hypoplasia (PCH), microcephaly, amyotrophic lateral sclerosis (ALS) and distal motor neuron dysfunctions. The mechanisms by which these VRK1 variant proteins contribute to the pathogenesis of these neurological syndromes are unknown. The syndromes are manifested when both of these rare VRK1 polymorphic alleles are implicated, either in homozygosis or compound heterozygosis. In this report, to identify the common underlying pathogenic mechanism of VRK1 polymorphisms, we have studied all human VRK1 variants identified in these neurological phenotypes from a biochemical point of view by molecular modeling, protein stability and kinase activity assays. Molecular modelling predicted that VRK1 variant proteins are either unstable or have an altered kinase activity. The stability and kinase activity of VRK1 pathogenic variants detected two groups. One composed by variants with a reduced protein stability: R133C, R358X, L195V, G135R and R321C. The other group includes VRK1variants with a reduced kinase activity tested on several substrates: histones H3 and H2AX, p53, c-Jun, coilin and 53BP1, a DNA repair protein. VRK1 variants with reduced kinase activity are H119R, R133C, G135R, V236M, R321C and R358X. The common underlying effect of VRK1 pathogenic variants with reduced protein stability or kinase activity is a functional insufficiency of VRK1 in patients with neuromotor developmental syndromes. The G135 variant cause a defective formation of 53BP1 foci in response to DNA damage, and loss Cajal bodies assembled on coilin.
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Affiliation(s)
- Elena Martín-Doncel
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC) - Universidad de Salamanca, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
| | - Ana M Rojas
- Centro Andaluz de Biología del Desarrollo (CABD), CSIC-Universidad Pablo de Olavide, Sevilla, Spain
- Instituto de Biomedicina de Sevilla (IBIS), CSIC-Universidad de Sevilla, Hospital Universitario Virgen del Rocío, Sevilla, Spain
| | - Lara Cantarero
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC) - Universidad de Salamanca, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
- Laboratorio de Neurogenética y Medicina Molecular, Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
| | - Pedro A Lazo
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC) - Universidad de Salamanca, Salamanca, Spain.
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain.
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29
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Do Cellular Condensates Accelerate Biochemical Reactions? Lessons from Microdroplet Chemistry. Biophys J 2019; 115:3-8. [PMID: 29972809 DOI: 10.1016/j.bpj.2018.05.023] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/03/2018] [Accepted: 05/23/2018] [Indexed: 01/20/2023] Open
Abstract
Cellular condensates-phase-separated concentrates of proteins and nucleic acids-provide organizational structure for biochemistry that is distinct from membrane-bound compartments. It has been suggested that one major function of cellular condensates is to accelerate biochemical processes that are normally slow or thermodynamically unfavorable. Yet, the mechanisms leading to increased reaction rates within cellular condensates remain poorly understood. In this article, we highlight recent advances in microdroplet chemistry that accelerate reaction rates by many orders of magnitude as compared to bulk and suggest that similar mechanisms may also affect reaction kinetics in cellular condensates.
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30
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Albrecht TR, Shevtsov SP, Wu Y, Mascibroda LG, Peart NJ, Huang KL, Sawyer IA, Tong L, Dundr M, Wagner EJ. Integrator subunit 4 is a 'Symplekin-like' scaffold that associates with INTS9/11 to form the Integrator cleavage module. Nucleic Acids Res 2019; 46:4241-4255. [PMID: 29471365 PMCID: PMC5934644 DOI: 10.1093/nar/gky100] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 02/17/2018] [Indexed: 12/14/2022] Open
Abstract
Integrator (INT) is a transcriptional regulatory complex associated with RNA polymerase II that is required for the 3′-end processing of both UsnRNAs and enhancer RNAs. Integrator subunits 9 (INTS9) and INTS11 constitute the catalytic core of INT and are paralogues of the cleavage and polyadenylation specificity factors CPSF100 and CPSF73. While CPSF73/100 are known to associate with a third protein called Symplekin, there is no paralog of Symplekin within INT raising the question of how INTS9/11 associate with the other INT subunits. Here, we have identified that INTS4 is a specific and conserved interaction partner of INTS9/11 that does not interact with either subunit individually. Although INTS4 has no significant homology with Symplekin, it possesses N-terminal HEAT repeats similar to Symplekin but also contains a β-sheet rich C-terminal region, both of which are important to bind INTS9/11. We assess three functions of INT including UsnRNA 3′-end processing, maintenance of Cajal body structural integrity, and formation of histone locus bodies to conclude that INTS4/9/11 are the most critical of the INT subunits for UsnRNA biogenesis. Altogether, these results indicate that INTS4/9/11 compose a heterotrimeric complex that likely represents the Integrator ‘cleavage module’ responsible for its endonucleolytic activity.
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Affiliation(s)
- Todd R Albrecht
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - Sergey P Shevtsov
- Department of Cell Biology, Rosalind Franklin University of Medicine and Science, Chicago Medical School, North Chicago, IL 60064, USA
| | - Yixuan Wu
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Lauren G Mascibroda
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - Natoya J Peart
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - Kai-Lieh Huang
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - Iain A Sawyer
- Department of Cell Biology, Rosalind Franklin University of Medicine and Science, Chicago Medical School, North Chicago, IL 60064, USA.,Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Miroslav Dundr
- Department of Cell Biology, Rosalind Franklin University of Medicine and Science, Chicago Medical School, North Chicago, IL 60064, USA
| | - Eric J Wagner
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
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31
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Hall AC, Ostrowski LA, Mekhail K. Phase Separation as a Melting Pot for DNA Repeats. Trends Genet 2019; 35:589-600. [DOI: 10.1016/j.tig.2019.05.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 05/03/2019] [Accepted: 05/07/2019] [Indexed: 12/23/2022]
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32
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Kim J, Han KY, Khanna N, Ha T, Belmont AS. Nuclear speckle fusion via long-range directional motion regulates speckle morphology after transcriptional inhibition. J Cell Sci 2019; 132:jcs.226563. [PMID: 30858197 DOI: 10.1242/jcs.226563] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 03/03/2019] [Indexed: 01/17/2023] Open
Abstract
Although the formation of RNA-protein bodies has been studied intensively, their mobility and how their number and size are regulated are still poorly understood. Here, we show significantly increased mobility of nuclear speckles after transcriptional inhibition, including long-range directed motion of one speckle towards another speckle, terminated by speckle fusion, over distances up to 4 µm and with velocities between 0.2 µm/min and 1.5 µm/min. Frequently, three or even four speckles follow very similar paths, with new speckles appearing along the path followed by a preceding speckle. Speckle movements and fusion events contribute to fewer, but larger, speckles after transcriptional inhibition. These speckle movements are not actin dependent, but occur within chromatin-depleted channels enriched with small granules containing the speckle marker protein SON. Similar long-range speckle movements and fusion events were observed after heat shock or heavy metal stress, and during late G2 and early prophase. Our observations suggest a mechanism for long-range, directional nuclear speckle movements, contributing to overall regulation of nuclear speckle number and size as well as overall nuclear organization. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Jiah Kim
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Kyu Young Han
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,Howard Hughes Medical Institute, Baltimore, MD 21205, USA.,CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, FL 32816, USA
| | - Nimish Khanna
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Taekjip Ha
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,Howard Hughes Medical Institute, Baltimore, MD 21205, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,Department of Biophysics and Biophysical Chemistry and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Andrew S Belmont
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA .,Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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33
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Cycles of protein condensation and discharge in nuclear organelles studied by fluorescence lifetime imaging. Nat Commun 2019; 10:455. [PMID: 30692529 PMCID: PMC6349932 DOI: 10.1038/s41467-019-08354-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 01/03/2019] [Indexed: 02/07/2023] Open
Abstract
Nuclear organelles are viscous droplets, created by concentration-dependent condensation and liquid–liquid phase separation of soluble proteins. Nuclear organelles have been actively investigated for their role in cellular regulation and disease. However, these studies are highly challenging to perform in live cells, and therefore, their physico-chemical properties are still poorly understood. In this study, we describe a fluorescence lifetime imaging approach for real-time monitoring of protein condensation in nuclear organelles of live cultured cells. This approach unravels surprisingly large cyclic changes in concentration of proteins in major nuclear organelles including nucleoli, nuclear speckles, Cajal bodies, as well as in the clusters of heterochromatin. Remarkably, protein concentration changes are synchronous for different organelles of the same cells. We propose a molecular mechanism responsible for synchronous accumulations of proteins in the nuclear organelles. This mechanism can serve for general regulation of cellular metabolism and contribute to coordination of gene expression. Studying the condensation of proteins into membraneless organelles in live cells is highly challenging. Here the authors develop a fluorescence lifetime imaging approach to monitor the condensation of proteins in nuclear organelles and report coordinated and cyclic changes in several nuclear organelles.
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Sawyer IA, Sturgill D, Dundr M. Membraneless nuclear organelles and the search for phases within phases. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 10:e1514. [DOI: 10.1002/wrna.1514] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 09/20/2018] [Accepted: 09/27/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Iain A. Sawyer
- Department of Cell Biology and Anatomy, Chicago Medical School Rosalind Franklin University of Medicine and Science North Chicago Illinois
- Laboratory of Receptor Biology and Gene Expression National Cancer Institute, National Institutes of Health Bethesda Maryland
| | - David Sturgill
- Laboratory of Receptor Biology and Gene Expression National Cancer Institute, National Institutes of Health Bethesda Maryland
| | - Miroslav Dundr
- Department of Cell Biology and Anatomy, Chicago Medical School Rosalind Franklin University of Medicine and Science North Chicago Illinois
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35
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Sawyer IA, Bartek J, Dundr M. Phase separated microenvironments inside the cell nucleus are linked to disease and regulate epigenetic state, transcription and RNA processing. Semin Cell Dev Biol 2018; 90:94-103. [PMID: 30017905 DOI: 10.1016/j.semcdb.2018.07.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 07/03/2018] [Indexed: 01/01/2023]
Abstract
Proteins and RNAs inside the cell nucleus are organized into distinct phases, also known as liquid-liquid phase separated (LLPS) droplet organelles or nuclear bodies. These regions exist within the spaces between chromatin-rich regions but their function is tightly linked to gene activity. They include major microscopically-observable structures such as the nucleolus, paraspeckle and Cajal body. The biochemical and assembly factors enriched inside these microenvironments regulate chromatin structure, transcription, and RNA processing, and other important cellular functions. Here, we describe published evidence that suggests nuclear bodies are bona fide LLPS droplet organelles and major regulators of the processes listed above. We also outline an updated "Supply or Sequester" model to describe nuclear body function, in which proteins or RNAs are supplied to surrounding genomic regions or sequestered away from their sites of activity. Finally, we describe recent evidence that suggests these microenvironments are both reflective and drivers of diverse pathophysiological states.
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Affiliation(s)
- Iain A Sawyer
- Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, United States; Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Jiri Bartek
- Danish Cancer, Society Research Center, Genome Integrity Unit, Copenhagen, Denmark; Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Miroslav Dundr
- Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, United States.
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36
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Winata CL, Korzh V. The translational regulation of maternal mRNAs in time and space. FEBS Lett 2018; 592:3007-3023. [PMID: 29972882 PMCID: PMC6175449 DOI: 10.1002/1873-3468.13183] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/29/2018] [Accepted: 06/29/2018] [Indexed: 12/16/2022]
Abstract
Since their discovery, the study of maternal mRNAs has led to the identification of mechanisms underlying their spatiotemporal regulation within the context of oogenesis and early embryogenesis. Following synthesis in the oocyte, maternal mRNAs are translationally silenced and sequestered into storage in cytoplasmic granules. At the same time, their unique distribution patterns throughout the oocyte and embryo are tightly controlled and connected to their functions in downstream embryonic processes. At certain points in oogenesis and early embryogenesis, maternal mRNAs are translationally activated to perform their functions in a timely manner. The cytoplasmic polyadenylation machinery is responsible for the translational activation of maternal mRNAs, and its role in initiating the maternal to zygotic transition events has recently come to light. Here, we summarize the current knowledge on maternal mRNA regulation, with particular focus on cytoplasmic polyadenylation as a mechanism for translational regulation.
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Affiliation(s)
- Cecilia Lanny Winata
- International Institute of Molecular and Cell Biology in Warsaw, Poland.,Max-Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Vladimir Korzh
- International Institute of Molecular and Cell Biology in Warsaw, Poland
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37
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Didychuk AL, Butcher SE, Brow DA. The life of U6 small nuclear RNA, from cradle to grave. RNA (NEW YORK, N.Y.) 2018; 24:437-460. [PMID: 29367453 PMCID: PMC5855946 DOI: 10.1261/rna.065136.117] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Removal of introns from precursor messenger RNA (pre-mRNA) and some noncoding transcripts is an essential step in eukaryotic gene expression. In the nucleus, this process of RNA splicing is carried out by the spliceosome, a multi-megaDalton macromolecular machine whose core components are conserved from yeast to humans. In addition to many proteins, the spliceosome contains five uridine-rich small nuclear RNAs (snRNAs) that undergo an elaborate series of conformational changes to correctly recognize the splice sites and catalyze intron removal. Decades of biochemical and genetic data, along with recent cryo-EM structures, unequivocally demonstrate that U6 snRNA forms much of the catalytic core of the spliceosome and is highly dynamic, interacting with three snRNAs, the pre-mRNA substrate, and >25 protein partners throughout the splicing cycle. This review summarizes the current state of knowledge on how U6 snRNA is synthesized, modified, incorporated into snRNPs and spliceosomes, recycled, and degraded.
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Affiliation(s)
- Allison L Didychuk
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - Samuel E Butcher
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - David A Brow
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53706, USA
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38
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Szczesny RJ, Kowalska K, Klosowska-Kosicka K, Chlebowski A, Owczarek EP, Warkocki Z, Kulinski TM, Adamska D, Affek K, Jedroszkowiak A, Kotrys AV, Tomecki R, Krawczyk PS, Borowski LS, Dziembowski A. Versatile approach for functional analysis of human proteins and efficient stable cell line generation using FLP-mediated recombination system. PLoS One 2018; 13:e0194887. [PMID: 29590189 PMCID: PMC5874048 DOI: 10.1371/journal.pone.0194887] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 03/12/2018] [Indexed: 12/21/2022] Open
Abstract
Deciphering a function of a given protein requires investigating various biological aspects. Usually, the protein of interest is expressed with a fusion tag that aids or allows subsequent analyses. Additionally, downregulation or inactivation of the studied gene enables functional studies. Development of the CRISPR/Cas9 methodology opened many possibilities but in many cases it is restricted to non-essential genes. Recombinase-dependent gene integration methods, like the Flp-In system, are very good alternatives. The system is widely used in different research areas, which calls for the existence of compatible vectors and efficient protocols that ensure straightforward DNA cloning and generation of stable cell lines. We have created and validated a robust series of 52 vectors for streamlined generation of stable mammalian cell lines using the FLP recombinase-based methodology. Using the sequence-independent DNA cloning method all constructs for a given coding-sequence can be made with just three universal PCR primers. Our collection allows tetracycline-inducible expression of proteins with various tags suitable for protein localization, FRET, bimolecular fluorescence complementation (BiFC), protein dynamics studies (FRAP), co-immunoprecipitation, the RNA tethering assay and cell sorting. Some of the vectors contain a bidirectional promoter for concomitant expression of miRNA and mRNA, so that a gene can be silenced and its product replaced by a mutated miRNA-insensitive version. Our toolkit and protocols have allowed us to create more than 500 constructs with ease. We demonstrate the efficacy of our vectors by creating stable cell lines with various tagged proteins (numatrin, fibrillarin, coilin, centrin, THOC5, PCNA). We have analysed transgene expression over time to provide a guideline for future experiments and compared the effectiveness of commonly used inducers for tetracycline-responsive promoters. As proof of concept we examined the role of the exoribonuclease XRN2 in transcription termination by RNAseq.
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Affiliation(s)
- Roman J. Szczesny
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
- * E-mail: (RJS); (AD)
| | - Katarzyna Kowalska
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Kamila Klosowska-Kosicka
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Aleksander Chlebowski
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Ewelina P. Owczarek
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Zbigniew Warkocki
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Tomasz M. Kulinski
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Dorota Adamska
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Kamila Affek
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Agata Jedroszkowiak
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Anna V. Kotrys
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Rafal Tomecki
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Pawel S. Krawczyk
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Lukasz S. Borowski
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Andrzej Dziembowski
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
- * E-mail: (RJS); (AD)
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Chujo T, Hirose T. Nuclear Bodies Built on Architectural Long Noncoding RNAs: Unifying Principles of Their Construction and Function. Mol Cells 2017; 40:889-896. [PMID: 29276943 PMCID: PMC5750707 DOI: 10.14348/molcells.2017.0263] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 11/20/2017] [Accepted: 11/20/2017] [Indexed: 11/27/2022] Open
Abstract
Nuclear bodies are subnuclear, spheroidal, and membraneless compartments that concentrate specific proteins and/or RNAs. They serve as sites of biogenesis, storage, and sequestration of specific RNAs, proteins, or ribonucleoprotein complexes. Recent studies reveal that a subset of nuclear bodies in various eukaryotic organisms is constructed using architectural long noncoding RNAs (arcRNAs). Here, we describe the unifying mechanistic principles of the construction and function of these bodies, especially focusing on liquid-liquid phase separation induced by architectural molecules that form multiple weakly adhesive interactions. We also discuss three possible advantages of using arcRNAs rather than architectural proteins to build the bodies: position-specificity, rapidity, and economy in sequestering nucleic acid-binding proteins. Moreover, we introduce two recently devised methods to discover novel arcRNA-constructed bodies; one that focuses on the RNase-sensitivity of these bodies, and another that focuses on "semi-extractability" of arcRNAs.
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Affiliation(s)
- Takeshi Chujo
- Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815,
Japan
| | - Tetsuro Hirose
- Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815,
Japan
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40
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Lin Y, Currie SL, Rosen MK. Intrinsically disordered sequences enable modulation of protein phase separation through distributed tyrosine motifs. J Biol Chem 2017; 292:19110-19120. [PMID: 28924037 PMCID: PMC5704491 DOI: 10.1074/jbc.m117.800466] [Citation(s) in RCA: 251] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Revised: 09/12/2017] [Indexed: 01/04/2023] Open
Abstract
Liquid–liquid phase separation (LLPS) is thought to contribute to the establishment of many biomolecular condensates, eukaryotic cell structures that concentrate diverse macromolecules but lack a bounding membrane. RNA granules control RNA metabolism and comprise a large class of condensates that are enriched in RNA-binding proteins and RNA molecules. Many RNA granule proteins are composed of both modular domains and intrinsically disordered regions (IDRs) having low amino acid sequence complexity. Phase separation of these molecules likely plays an important role in the generation and stability of RNA granules. To understand how folded domains and IDRs can cooperate to modulate LLPS, we generated a series of engineered proteins. These were based on fusions of an IDR derived from the RNA granule protein FUS (fused in sarcoma) to a multivalent poly-Src homology 3 (SH3) domain protein that phase-separates when mixed with a poly-proline–rich-motif (polyPRM) ligand. We found that the wild-type IDR promotes LLPS of the polySH3–polyPRM system, decreasing the phase separation threshold concentration by 8-fold. Systematic mutation of tyrosine residues in Gly/Ser-Tyr-Gly/Ser motifs of the IDR reduced this effect, depending on the number but not on the position of these substitutions. Mutating all tyrosines to non-aromatic residues or phosphorylating the IDR raised the phase separation threshold above that of the unmodified polySH3–polyPRM pair. These results show that low-complexity IDRs can modulate LLPS both positively and negatively, depending on the degree of aromaticity and phosphorylation status. Our findings provide plausible mechanisms by which these sequences could alter RNA granule properties on evolutionary and cellular timescales.
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Affiliation(s)
- Yuan Lin
- From the Department of Biophysics, University of Texas Southwestern Medical Center and.,the Howard Hughes Medical Institute, Dallas, Texas 75390
| | - Simon L Currie
- From the Department of Biophysics, University of Texas Southwestern Medical Center and.,the Howard Hughes Medical Institute, Dallas, Texas 75390
| | - Michael K Rosen
- From the Department of Biophysics, University of Texas Southwestern Medical Center and .,the Howard Hughes Medical Institute, Dallas, Texas 75390
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41
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Raimer AC, Gray KM, Matera AG. SMN - A chaperone for nuclear RNP social occasions? RNA Biol 2017; 14:701-711. [PMID: 27648855 PMCID: PMC5519234 DOI: 10.1080/15476286.2016.1236168] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 09/01/2016] [Accepted: 09/09/2016] [Indexed: 12/24/2022] Open
Abstract
Survival Motor Neuron (SMN) protein localizes to both the nucleus and the cytoplasm. Cytoplasmic SMN is diffusely localized in large oligomeric complexes with core member proteins, called Gemins. Biochemical and cell biological studies have demonstrated that the SMN complex is required for the cytoplasmic assembly and nuclear transport of Sm-class ribonucleoproteins (RNPs). Nuclear SMN accumulates with spliceosomal small nuclear (sn)RNPs in Cajal bodies, sub-domains involved in multiple facets of snRNP maturation. Thus, the SMN complex forms stable associations with both nuclear and cytoplasmic snRNPs, and plays a critical role in their biogenesis. In this review, we focus on potential functions of the nuclear SMN complex, with particular emphasis on its role within the Cajal body.
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Affiliation(s)
- Amanda C. Raimer
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Kelsey M. Gray
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - A. Gregory Matera
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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42
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Sawyer IA, Hager GL, Dundr M. Specific genomic cues regulate Cajal body assembly. RNA Biol 2017; 14:791-803. [PMID: 27715441 PMCID: PMC5519236 DOI: 10.1080/15476286.2016.1243648] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/06/2016] [Accepted: 09/27/2016] [Indexed: 02/07/2023] Open
Abstract
The assembly of specialized sub-nuclear microenvironments known as nuclear bodies (NBs) is important for promoting efficient nuclear function. In particular, the Cajal body (CB), a prominent NB that facilitates spliceosomal snRNP biogenesis, assembles in response to genomic cues. Here, we detail the factors that regulate CB assembly and structural maintenance. These include the importance of transcription at nucleating gene loci, the grouping of these genes on human chromosomes 1, 6 and 17, as well as cell cycle and biochemical regulation of CB protein function. We also speculate on the correlation between CB formation and RNA splicing levels in neurons and cancer. The timing and location of these specific molecular events is critical to CB assembly and its contribution to genome function. However, further work is required to explore the emerging biophysical characteristics of CB assembly and the impact upon subsequent genome reorganization.
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Affiliation(s)
- Iain A. Sawyer
- Department of Cell Biology, Rosalind Franklin University of Medicine & Science, Chicago Medical School, North Chicago, IL, USA
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Gordon L. Hager
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Miroslav Dundr
- Department of Cell Biology, Rosalind Franklin University of Medicine & Science, Chicago Medical School, North Chicago, IL, USA
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43
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Banani SF, Lee HO, Hyman AA, Rosen MK. Biomolecular condensates: organizers of cellular biochemistry. Nat Rev Mol Cell Biol 2017; 18:285-298. [PMID: 28225081 PMCID: PMC7434221 DOI: 10.1038/nrm.2017.7] [Citation(s) in RCA: 3199] [Impact Index Per Article: 457.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Biomolecular condensates are micron-scale compartments in eukaryotic cells that lack surrounding membranes but function to concentrate proteins and nucleic acids. These condensates are involved in diverse processes, including RNA metabolism, ribosome biogenesis, the DNA damage response and signal transduction. Recent studies have shown that liquid-liquid phase separation driven by multivalent macromolecular interactions is an important organizing principle for biomolecular condensates. With this physical framework, it is now possible to explain how the assembly, composition, physical properties and biochemical and cellular functions of these important structures are regulated.
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Affiliation(s)
- Salman F. Banani
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Hyun O. Lee
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Anthony A. Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Michael K. Rosen
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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44
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Aguilera-Gomez A, Rabouille C. Membrane-bound organelles versus membrane-less compartments and their control of anabolic pathways in Drosophila. Dev Biol 2017; 428:310-317. [PMID: 28377034 DOI: 10.1016/j.ydbio.2017.03.029] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 03/27/2017] [Accepted: 03/27/2017] [Indexed: 12/29/2022]
Abstract
Classically, we think of cell compartmentalization as being achieved by membrane-bound organelles. It has nevertheless emerged that membrane-less assemblies also largely contribute to this compartmentalization. Here, we compare the characteristics of both types of compartmentalization in term of maintenance of functional identities. Furthermore, membrane less-compartments are critical for sustaining developmental and cell biological events as they control major metabolic pathways. We describe two examples related to this issue in Drosophila, the role of P-bodies in the translational control of gurken in the Drosophila oocyte, and the formation of Sec bodies upon amino-acid starvation in Drosophila cells.
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Affiliation(s)
| | - Catherine Rabouille
- Hubrecht Institute of the KNAW & UMC Utrecht, 3584 CT Utrecht, The Netherlands; Department of Cell Biology, UMC Utrecht, The Netherlands; Department of Cell Biology, UMC Groningen, The Netherlands.
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45
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Neural Differentiation in HDAC1-Depleted Cells Is Accompanied by Coilin Downregulation and the Accumulation of Cajal Bodies in Nucleoli. Stem Cells Int 2017; 2017:1021240. [PMID: 28337219 PMCID: PMC5350323 DOI: 10.1155/2017/1021240] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 01/12/2017] [Accepted: 01/26/2017] [Indexed: 12/23/2022] Open
Abstract
Cajal bodies (CBs) are important compartments containing accumulated proteins that preferentially regulate RNA-related nuclear events, including splicing. Here, we studied the nuclear distribution pattern of CBs in neurogenesis. In adult brains, coilin was present at a high density, but CB formation was absent in the nuclei of the choroid plexus of the lateral ventricles. Cells of the adult hippocampus were characterized by a crescent-like morphology of coilin protein. We additionally observed a 70 kDa splice variant of coilin in adult mouse brains, which was different to embryonic brains and mouse pluripotent embryonic stem cells (mESCs), characterized by the 80 kDa standard variant of coilin. Here, we also showed that depletion of coilin is induced during neural differentiation and HDAC1 deficiency in mESCs caused coilin accumulation inside the fibrillarin-positive region of the nucleoli. A similar distribution pattern was observed in adult brain hippocampi, characterized by lower levels of both coilin and HDAC1. In summary, we observed that neural differentiation and HDAC1 deficiency lead to coilin depletion and coilin accumulation in body-like structures inside the nucleoli.
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46
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Duronio RJ, Marzluff WF. Coordinating cell cycle-regulated histone gene expression through assembly and function of the Histone Locus Body. RNA Biol 2017; 14:726-738. [PMID: 28059623 DOI: 10.1080/15476286.2016.1265198] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Metazoan replication-dependent (RD) histone genes encode the only known cellular mRNAs that are not polyadenylated. These mRNAs end instead in a conserved stem-loop, which is formed by an endonucleolytic cleavage of the pre-mRNA. The genes for all 5 histone proteins are clustered in all metazoans and coordinately regulated with high levels of expression during S phase. Production of histone mRNAs occurs in a nuclear body called the Histone Locus Body (HLB), a subdomain of the nucleus defined by a concentration of factors necessary for histone gene transcription and pre-mRNA processing. These factors include the scaffolding protein NPAT, essential for histone gene transcription, and FLASH and U7 snRNP, both essential for histone pre-mRNA processing. Histone gene expression is activated by Cyclin E/Cdk2-mediated phosphorylation of NPAT at the G1-S transition. The concentration of factors within the HLB couples transcription with pre-mRNA processing, enhancing the efficiency of histone mRNA biosynthesis.
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Affiliation(s)
- Robert J Duronio
- a Department of Biology , University of North Carolina , Chapel Hill , NC , USA.,b Department of Genetics , University of North Carolina , Chapel Hill , NC , USA.,c Integrative Program for Biological and Genome Sciences , University of North Carolina , Chapel Hill , NC , USA.,d Lineberger Comprehensive Cancer Center , University of North Carolina , Chapel Hill , NC , USA
| | - William F Marzluff
- a Department of Biology , University of North Carolina , Chapel Hill , NC , USA.,c Integrative Program for Biological and Genome Sciences , University of North Carolina , Chapel Hill , NC , USA.,d Lineberger Comprehensive Cancer Center , University of North Carolina , Chapel Hill , NC , USA.,e Department of Biochemistry and Biophysics , University of North Carolina , Chapel Hill , NC , USA
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47
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Heyn P, Salmonowicz H, Rodenfels J, Neugebauer KM. Activation of transcription enforces the formation of distinct nuclear bodies in zebrafish embryos. RNA Biol 2016; 14:752-760. [PMID: 27858508 DOI: 10.1080/15476286.2016.1255397] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Nuclear bodies are cellular compartments that lack lipid bilayers and harbor specific RNAs and proteins. Recent proposals that nuclear bodies form through liquid-liquid phase separation leave the question of how different nuclear bodies maintain their distinct identities unanswered. Here we investigate Cajal bodies (CBs), histone locus bodies (HLBs) and nucleoli - involved in assembly of the splicing machinery, histone mRNA 3' end processing, and rRNA processing, respectively - in the embryos of the zebrafish, Danio rerio. We take advantage of the transcriptional silence of the 1-cell embryo and follow nuclear body appearance as zygotic transcription becomes activated. CBs are present from fertilization onwards, while HLB and nucleolar components formed foci several hours later when histone genes and rDNA became active. HLB formation was blocked by transcription inhibition, suggesting nascent histone transcripts recruit HLB components like U7 snRNP. Surprisingly, we found that U7 base-pairing with nascent histone transcripts was not required for localization to HLBs. Rather, the type of Sm ring assembled on U7 determined its targeting to HLBs or CBs; the spliceosomal Sm ring targeted snRNAs to CBs while the specialized U7 Sm-ring localized to HLBs, demonstrating the contribution of protein constituents to the distinction among nuclear bodies. Thus, nucleolar, HLB, and CB components can mix in early embryogenesis when transcription is naturally or artificially silenced. These data support a model in which transcription of specific gene loci nucleates nuclear body components with high specificity and fidelity to perform distinct regulatory functions.
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Affiliation(s)
- Patricia Heyn
- a Max Planck Institute of Molecular Cell Biology and Genetics , Dresden , Germany
| | - Hanna Salmonowicz
- a Max Planck Institute of Molecular Cell Biology and Genetics , Dresden , Germany
| | - Jonathan Rodenfels
- b Department of Molecular Biophysics & Biochemistry , Yale University , New Haven , CT , USA
| | - Karla M Neugebauer
- b Department of Molecular Biophysics & Biochemistry , Yale University , New Haven , CT , USA
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48
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Sawyer IA, Sturgill D, Sung MH, Hager GL, Dundr M. Cajal body function in genome organization and transcriptome diversity. Bioessays 2016; 38:1197-1208. [PMID: 27767214 DOI: 10.1002/bies.201600144] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Nuclear bodies contribute to non-random organization of the human genome and nuclear function. Using a major prototypical nuclear body, the Cajal body, as an example, we suggest that these structures assemble at specific gene loci located across the genome as a result of high transcriptional activity. Subsequently, target genes are physically clustered in close proximity in Cajal body-containing cells. However, Cajal bodies are observed in only a limited number of human cell types, including neuronal and cancer cells. Ultimately, Cajal body depletion perturbs splicing kinetics by reducing target small nuclear RNA (snRNA) transcription and limiting the levels of spliceosomal snRNPs, including their modification and turnover following each round of RNA splicing. As such, Cajal bodies are capable of shaping the chromatin interaction landscape and the transcriptome by influencing spliceosome kinetics. Future studies should concentrate on characterizing the direct influence of Cajal bodies upon snRNA gene transcriptional dynamics. Also see the video abstract here.
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Affiliation(s)
- Iain A Sawyer
- Department of Cell Biology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA.,Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - David Sturgill
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Myong-Hee Sung
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Gordon L Hager
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Miroslav Dundr
- Department of Cell Biology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
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49
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Banani SF, Rice AM, Peeples WB, Lin Y, Jain S, Parker R, Rosen MK. Compositional Control of Phase-Separated Cellular Bodies. Cell 2016; 166:651-663. [PMID: 27374333 DOI: 10.1016/j.cell.2016.06.010] [Citation(s) in RCA: 771] [Impact Index Per Article: 96.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 03/13/2016] [Accepted: 06/01/2016] [Indexed: 12/12/2022]
Abstract
Cellular bodies such as P bodies and PML nuclear bodies (PML NBs) appear to be phase-separated liquids organized by multivalent interactions among proteins and RNA molecules. Although many components of various cellular bodies are known, general principles that define body composition are lacking. We modeled cellular bodies using several engineered multivalent proteins and RNA. In vitro and in cells, these scaffold molecules form phase-separated liquids that concentrate low valency client proteins. Clients partition differently depending on the ratio of scaffolds, with a sharp switch across the phase diagram diagonal. Composition can switch rapidly through changes in scaffold concentration or valency. Natural PML NBs and P bodies show analogous partitioning behavior, suggesting how their compositions could be controlled by levels of PML SUMOylation or cellular mRNA concentration, respectively. The data suggest a conceptual framework for considering the composition and control thereof of cellular bodies assembled through heterotypic multivalent interactions.
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Affiliation(s)
- Salman F Banani
- Department of Biophysics and Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Allyson M Rice
- Department of Biophysics and Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - William B Peeples
- Department of Biophysics and Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Yuan Lin
- Department of Biophysics and Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Saumya Jain
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80309, USA
| | - Roy Parker
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80309, USA
| | - Michael K Rosen
- Department of Biophysics and Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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50
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Courchaine EM, Lu A, Neugebauer KM. Droplet organelles? EMBO J 2016; 35:1603-12. [PMID: 27357569 DOI: 10.15252/embj.201593517] [Citation(s) in RCA: 213] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 06/03/2016] [Indexed: 12/12/2022] Open
Abstract
Cells contain numerous, molecularly distinct cellular compartments that are not enclosed by lipid bilayers. These compartments are implicated in a wide range of cellular activities, and they have been variously described as bodies, granules, or organelles. Recent evidence suggests that a liquid-liquid phase separation (LLPS) process may drive their formation, possibly justifying the unifying term "droplet organelle". A veritable deluge of recent publications points to the importance of low-complexity proteins and RNA in determining the physical properties of phase-separated structures. Many of the proteins linked to such structures are implicated in human diseases, such as amyotrophic lateral sclerosis (ALS). We provide an overview of the organizational principles that characterize putative "droplet organelles" in healthy and diseased cells, connecting protein biochemistry with cell physiology.
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Affiliation(s)
- Edward M Courchaine
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Alice Lu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
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