1
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Zhang W, Li Z, Wang X, Sun T. Phase separation is regulated by post-translational modifications and participates in the developments of human diseases. Heliyon 2024; 10:e34035. [PMID: 39071719 PMCID: PMC11279762 DOI: 10.1016/j.heliyon.2024.e34035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 06/30/2024] [Accepted: 07/02/2024] [Indexed: 07/30/2024] Open
Abstract
Liquid-liquid phase separation (LLPS) of intracellular proteins has emerged as a hot research topic in recent years. Membrane-less and liquid-like condensates provide dense spaces that ensure cells to high efficiently regulate genes transcription and rapidly respond to burst changes from the environment. The fomation and activity of LLPS are not only modulated by the cytosol conditions including but not limited to salt concentration and temperture. Interestingly, recent studies have shown that phase separation is also regulated by various post-translational modifications (PTMs) through modulating proteins multivalency, such as solubility and charge interactions. The regulation mechanism is crucial for normal functioning of cells, as aberrant protein aggregates are often closely related with the occurrence and development of human diseases including cancer and nurodegenerative diseases. Therefore, studying phase separation in the perspective of protein PTMs has long-term significance for human health. In this review, we summarized the properties and cellular physiological functions of LLPS, particularly its relationships with PTMs in human diseases according to recent researches.
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Affiliation(s)
- Weibo Zhang
- Faculty of Health Sciences Building University of Macau E12 Avenida da Universidade, Taipa, Macau, China
| | - Zhengfeng Li
- Faculty of Health Sciences Building University of Macau E12 Avenida da Universidade, Taipa, Macau, China
| | - Xianju Wang
- Faculty of Health Sciences Building University of Macau E12 Avenida da Universidade, Taipa, Macau, China
| | - Ting Sun
- Faculty of Health Sciences Building University of Macau E12 Avenida da Universidade, Taipa, Macau, China
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2
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Liu Y, Feng W, Wang Y, Wu B. Crosstalk between protein post-translational modifications and phase separation. Cell Commun Signal 2024; 22:110. [PMID: 38347544 PMCID: PMC10860296 DOI: 10.1186/s12964-023-01380-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 11/02/2023] [Indexed: 02/15/2024] Open
Abstract
The phenomenon of phase separation is quite common in cells, and it is involved in multiple processes of life activities. However, the current research on the correlation between protein modifications and phase separation and the interference with the tendency of phase separation has some limitations. Here we focus on several post-translational modifications of proteins, including protein phosphorylation modification at multiple sites, methylation modification, acetylation modification, ubiquitination modification, SUMOylation modification, etc., which regulate the formation of phase separation and the stability of phase separation structure through multivalent interactions. This regulatory role is closely related to the development of neurodegenerative diseases, tumors, viral infections, and other diseases, and also plays essential functions in environmental stress, DNA damage repair, transcriptional regulation, signal transduction, and cell homeostasis of living organisms, which provides an idea to explore the interaction between novel protein post-translational modifications and phase separation. Video Abstract.
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Affiliation(s)
- Yang Liu
- Jinan Central Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Wenjuan Feng
- Department of Reproductive Medicine, Central Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Yunshan Wang
- Jinan Central Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
- Basic Medical Research Center, Central Hospital Affiliated to Shandong First Medical University, Jinan, China.
| | - Bin Wu
- Jinan Central Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
- Department of Reproductive Medicine, Central Hospital Affiliated to Shandong First Medical University, Jinan, China.
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3
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Zhang H, Zhang T, Wan X, Chen C, Wang S, Qin D, Li L, Yu L, Wu X. LSM14B coordinates protein component expression in the P-body and controls oocyte maturation. J Genet Genomics 2024; 51:48-60. [PMID: 37481122 DOI: 10.1016/j.jgg.2023.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 07/13/2023] [Accepted: 07/14/2023] [Indexed: 07/24/2023]
Abstract
The generation of mature and healthy oocytes is the most critical event in the entire female reproductive process, and the mechanisms regulating this process remain to be studied. Here, we demonstrate that Smith-like (LSM) family member 14B (LSM14B) regulates oocyte maturation, and the loss of LSM14B in mouse ovaries leads to abnormal oocyte MII arrest and female infertility. Next, we find the aberrant transcriptional activation, indicated by abnormal non-surrounded nucleolus and surrounded nucleolus oocyte proportions, and abnormal chromosome assembly and segregation in Lsm14b-deficient mouse oocytes. The global transcriptome analysis suggests that many transcripts involved in cytoplasmic processing body (P-body) function are altered in Lsm14b-deficient mouse oocytes. Deletion of Lsm14b results in the expression and/or localization changes of P-body components (such as LSM14A, DCP1A, and 4E-T). Notably, DDX6, a key component of the P-body, is downregulated and accumulates in the nuclei in Lsm14b-deficient mouse oocytes. Taken together, our data suggest that LSM14B links mouse oocyte maturation to female fertility through the regulation of the P-body.
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Affiliation(s)
- Huiru Zhang
- State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Tao Zhang
- State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Xiang Wan
- State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Chang Chen
- State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Shu Wang
- State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Dongdong Qin
- State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Lufan Li
- State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Luping Yu
- Center for Reproductive Medicine and Obstetrics and Gynecology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, Jiangsu 210029, China.
| | - Xin Wu
- State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
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4
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Chowdhury MN, Chen X, Jin H. An intrinsically Disordered RNA Binding Protein Modulates mRNA Translation and Storage. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.22.541713. [PMID: 37293096 PMCID: PMC10245857 DOI: 10.1101/2023.05.22.541713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Many proteins with intrinsically disordered regions interact with cytoplasmic ribosomes. However, many of the molecular functions related to these interactions are unclear. In this study, using an abundant RNA-binding protein with a structurally well-defined RNA recognition motif and an intrinsically disordered RGG domain as a model system, we investigated how this protein modulates mRNA storage and translation. Using genomic and molecular approaches, we show that the presence of Sbp1 slows ribosome movement on cellular mRNAs and promotes polysome stalling. Sbp1-associated polysomes display a ring-shaped structure in addition to a beads-on-string morphology visualized under electron microscope. Moreover, post-translational modifications at the RGG motif play important roles in directing cellular mRNAs to either translation or storage. Finally, binding of Sbp1 to the 5'UTRs of mRNAs represses both cap-dependent and cap-independent translation initiation of proteins functionally important for general protein synthesis in the cell. Taken together, our study demonstrates an intrinsically disordered RNA binding protein regulates mRNA translation and storage via distinctive mechanisms under physiological conditions and establishes a framework with which functions of important RGG-proteins can be investigated and defined.
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Affiliation(s)
- Mashiat N. Chowdhury
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801
| | - Xin Chen
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801
| | - Hong Jin
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801
- Carl R. Woese Institute for Genomic Biology, 1206 West Gregory Drive, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801
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5
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Chowdhury MN, Jin H. The RGG motif proteins: Interactions, functions, and regulations. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1748. [PMID: 35661420 PMCID: PMC9718894 DOI: 10.1002/wrna.1748] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 04/25/2022] [Accepted: 05/09/2022] [Indexed: 01/31/2023]
Abstract
Proteins with motifs rich in arginines and glycines were discovered decades ago and are functionally involved in a staggering range of essential processes in the cell. Versatile, specific, yet adaptable molecular interactions enabled by the unique combination of arginine and glycine, combined with multiplicity of molecular recognition conferred by repeated di-, tri-, and multiple peptide motifs, allow RGG motif proteins to interact with a broad range of proteins and nucleic acids. Furthermore, posttranslational modifications at the arginines in the motif extend the RGG protein's capacity for a fine-tuned regulation. In this review, we focus on the biochemical properties of the RGG motif, its molecular interactions with RNAs and proteins, and roles of the posttranslational modification in modulating their interactions. We discuss current knowledge of the RGG motif proteins involved in mRNA transport and translation, highlight our merging understanding of their molecular functions in translational regulation and summarize areas of research in the future critical in understanding this important family of proteins. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Translation > Mechanisms.
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Affiliation(s)
- Mashiat N. Chowdhury
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801
| | - Hong Jin
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801,Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801,Carl R. Woese Institute for Genomic Biology, 1206 West Gregory Drive, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801,Corresponding author: Phone: (217)244-9493, Fax: (217)244-5858,
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6
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Ren J, Zhang Z, Zong Z, Zhang L, Zhou F. Emerging Implications of Phase Separation in Cancer. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202855. [PMID: 36117111 PMCID: PMC9631093 DOI: 10.1002/advs.202202855] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 08/26/2022] [Indexed: 05/19/2023]
Abstract
In eukaryotic cells, biological activities are executed in distinct cellular compartments or organelles. Canonical organelles with membrane-bound structures are well understood. Cells also inherently contain versatile membrane-less organelles (MLOs) that feature liquid or gel-like bodies. A biophysical process termed liquid-liquid phase separation (LLPS) elucidates how MLOs form through dynamic biomolecule assembly. LLPS-related molecules often have multivalency, which is essential for low-affinity inter- or intra-molecule interactions to trigger phase separation. Accumulating evidence shows that LLPS concentrates and organizes desired molecules or segregates unneeded molecules in cells. Thus, MLOs have tunable functional specificity in response to environmental stimuli and metabolic processes. Aberrant LLPS is widely associated with several hallmarks of cancer, including sustained proliferative signaling, growth suppressor evasion, cell death resistance, telomere maintenance, DNA damage repair, etc. Insights into the molecular mechanisms of LLPS provide new insights into cancer therapeutics. Here, the current understanding of the emerging concepts of LLPS and its involvement in cancer are comprehensively reviewed.
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Affiliation(s)
- Jiang Ren
- School of MedicineZhejiang University City CollegeHangzhou215123China
- The Eighth Affiliated HospitalSun Yat‐sen UniversityShenzhen518033China
| | - Zhenyu Zhang
- Department of NeurosurgeryThe First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenan450003China
| | - Zhi Zong
- MOE Key Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling NetworkLife Sciences InstituteZhejiang UniversityHangzhou310058China
| | - Long Zhang
- MOE Key Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling NetworkLife Sciences InstituteZhejiang UniversityHangzhou310058China
- International Biomed‐X Research Center, Second Affiliated Hospital of Zhejiang University School of MedicineZhejiang UniversityHangzhouChina
- Cancer CenterZhejiang UniversityHangzhou215123China
| | - Fangfang Zhou
- School of MedicineZhejiang University City CollegeHangzhou215123China
- Institutes of Biology and Medical SciencesSoochow UniversitySuzhou215123China
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7
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Abstract
The 5'-terminal cap is a fundamental determinant of eukaryotic gene expression which facilitates cap-dependent translation and protects mRNAs from exonucleolytic degradation. Enzyme-directed hydrolysis of the cap (decapping) decisively affects mRNA expression and turnover, and is a heavily regulated event. Following the identification of the decapping holoenzyme (Dcp1/2) over two decades ago, numerous studies revealed the complexity of decapping regulation across species and cell types. A conserved set of Dcp1/2-associated proteins, implicated in decapping activation and molecular scaffolding, were identified through genetic and molecular interaction studies, and yet their exact mechanisms of action are only emerging. In this review, we discuss the prevailing models on the roles and assembly of decapping co-factors, with considerations of conservation across species and comparison across physiological contexts. We next discuss the functional convergences of decapping machineries with other RNA-protein complexes in cytoplasmic P bodies and compare current views on their impact on mRNA stability and translation. Lastly, we review the current models of decapping activation and highlight important gaps in our current understanding.
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Affiliation(s)
- Elva Vidya
- Goodman Cancer Institute, McGill University, Montréal, QC, Canada
- Department of Biochemistry, McGill University, Montréal, QC, Canada
| | - Thomas F. Duchaine
- Goodman Cancer Institute, McGill University, Montréal, QC, Canada
- Department of Biochemistry, McGill University, Montréal, QC, Canada
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8
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The Novel Protease Activities of JMJD5–JMJD6–JMJD7 and Arginine Methylation Activities of Arginine Methyltransferases Are Likely Coupled. Biomolecules 2022; 12:biom12030347. [PMID: 35327545 PMCID: PMC8945206 DOI: 10.3390/biom12030347] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 02/03/2022] [Accepted: 02/18/2022] [Indexed: 12/23/2022] Open
Abstract
The surreptitious discoveries of the protease activities on arginine-methylated targets of a subfamily of Jumonji domain-containing family including JMJD5, JMJD6, and JMJD7 pose several questions regarding their authenticity, function, purpose, and relations with others. At the same time, despite several decades of efforts and massive accumulating data regarding the roles of the arginine methyltransferase family (PRMTs), the exact function of this protein family still remains a mystery, though it seems to play critical roles in transcription regulation, including activation and inactivation of a large group of genes, as well as other biological activities. In this review, we aim to elucidate that the function of JMJD5/6/7 and PRMTs are likely coupled. Besides roles in the regulation of the biogenesis of membrane-less organelles in cells, they are major players in regulating stimulating transcription factors to control the activities of RNA Polymerase II in higher eukaryotes, especially in the animal kingdom. Furthermore, we propose that arginine methylation by PRMTs could be a ubiquitous action marked for destruction after missions by a subfamily of the Jumonji protein family.
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9
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Li W, Jiang C, Zhang E. Advances in the phase separation-organized membraneless organelles in cells: a narrative review. Transl Cancer Res 2022; 10:4929-4946. [PMID: 35116344 PMCID: PMC8797891 DOI: 10.21037/tcr-21-1111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 10/29/2021] [Indexed: 11/26/2022]
Abstract
Membraneless organelles (MLOs) are micro-compartments that lack delimiting membranes, concentrating several macro-molecules with a high local concentration in eukaryotic cells. Recent studies have shown that MLOs have pivotal roles in multiple biological processes, including gene transcription, RNA metabolism, translation, protein modification, and signal transduction. These biological processes in cells have essential functions in many diseases, such as cancer, neurodegenerative diseases, and virus-related diseases. The liquid-liquid phase separation (LLPS) microenvironment within cells is thought to be the driving force for initiating the formation of micro-compartments with a liquid-like property, becoming an important organizing principle for MLOs to mediate organism responses. In this review, we comprehensively elucidated the formation of these MLOs and the relationship between biological functions and associated diseases. The mechanisms underlying the influence of protein concentration and valency on phase separation in cells are also discussed. MLOs undergoing the LLPS process have diverse functions, including stimulation of some adaptive and reversible responses to alter the transcriptional or translational processes, regulation of the concentrations of biomolecules in living cells, and maintenance of cell morphogenesis. Finally, we highlight that the development of this field could pave the way for developing novel therapeutic strategies for the treatment of LLPS-related diseases based on the understanding of phase separation in the coming years.
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Affiliation(s)
- Weihan Li
- Department of Immunology, School of Medicine, Nantong University, Nantong, China
| | - Chenwei Jiang
- Department of Immunology, School of Medicine, Nantong University, Nantong, China
| | - Erhao Zhang
- Department of Immunology, School of Medicine, Nantong University, Nantong, China.,Laboratory of Medical Science, School of Medicine, Nantong University, Nantong, China
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10
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Schisa JA, Elaswad MT. An Emerging Role for Post-translational Modifications in Regulating RNP Condensates in the Germ Line. Front Mol Biosci 2021; 8:658020. [PMID: 33898525 PMCID: PMC8060454 DOI: 10.3389/fmolb.2021.658020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 03/19/2021] [Indexed: 12/12/2022] Open
Abstract
RNA-binding proteins undergo regulated phase transitions in an array of cell types. The phase separation of RNA-binding proteins, and subsequent formation of RNP condensates or granules, occurs during physiological conditions and can also be induced by stress. Some RNP granules have roles in post-transcriptionally regulating mRNAs, and mutations that prevent the condensation of RNA-binding proteins can reduce an organism's fitness. The reversible and multivalent interactions among RNP granule components can result in RNP complexes that transition among diffuse and condensed states, the latter of which can be pathological; for example, in neurons solid RNP aggregates contribute to disease states such as amyotrophic lateral sclerosis (ALS), and the dysregulation of RNP granules in human germ cells may be involved in Fragile X-associated primary ovarian insufficiency. Thus, regulating the assembly of mRNAs and RNA-binding proteins into discrete granules appears to provide important functions at both cellular and physiological levels. Here we review our current understanding of the role of post-translational modifications (PTMs) in regulating the condensation of RNA-binding proteins in the germ line. We compare and contrast the in vitro evidence that methylation inhibits phase separation of RNA binding proteins, with the extent to which these results apply to the in vivo germ line environment of several model systems. We also focus on the role of phosphorylation in modulating the dynamics of RNP granules in the germ line. Finally, we consider the gaps that exist in our understanding of the role of PTMs in regulating germ line RNP granules.
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Affiliation(s)
- Jennifer A Schisa
- Department of Biology, Central Michigan University, Mount Pleasant, MI, United States
| | - Mohamed T Elaswad
- Department of Biology, Central Michigan University, Mount Pleasant, MI, United States
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11
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Gill AL, Premasiri AS, Vieira FG. Hypothesis and Theory: Roles of Arginine Methylation in C9orf72-Mediated ALS and FTD. Front Cell Neurosci 2021; 15:633668. [PMID: 33833668 PMCID: PMC8021787 DOI: 10.3389/fncel.2021.633668] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/09/2021] [Indexed: 12/11/2022] Open
Abstract
Hexanucleotide repeat expansion (G4C2n) mutations in the gene C9ORF72 account for approximately 30% of familial cases of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), as well as approximately 7% of sporadic cases of ALS. G4C2n mutations are known to result in the production of five species of dipeptide repeat proteins (DRPs) through non-canonical translation processes. Arginine-enriched dipeptide repeat proteins, glycine-arginine (polyGR), and proline-arginine (polyPR) have been demonstrated to be cytotoxic and deleterious in multiple experimental systems. Recently, we and others have implicated methylation of polyGR/polyPR arginine residues in disease processes related to G4C2n mutation-mediated neurodegeneration. We previously reported that inhibition of asymmetric dimethylation (ADMe) of arginine residues is protective in cell-based models of polyGR/polyPR cytotoxicity. These results are consistent with the idea that PRMT-mediated arginine methylation in the context of polyGR/polyPR exposure is harmful. However, it remains unclear why. Here we discuss the influence of arginine methylation on diverse cellular processes including liquid-liquid phase separation, chromatin remodeling, transcription, RNA processing, and RNA-binding protein localization, and we consider how methylation of polyGR/polyPR may disrupt processes essential for normal cellular function and survival.
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Affiliation(s)
- Anna L Gill
- ALS Therapy Development Institute, Cambridge, MA, United States
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12
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Perdikari TM, Jovic N, Dignon GL, Kim YC, Fawzi NL, Mittal J. A predictive coarse-grained model for position-specific effects of post-translational modifications. Biophys J 2021; 120:1187-1197. [PMID: 33582133 DOI: 10.1016/j.bpj.2021.01.034] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 12/29/2020] [Accepted: 01/19/2021] [Indexed: 02/06/2023] Open
Abstract
Biomolecules undergo liquid-liquid phase separation (LLPS), resulting in the formation of multicomponent protein-RNA membraneless organelles in cells. However, the physiological and pathological role of post-translational modifications (PTMs) on the biophysics of phase behavior is only beginning to be probed. To study the effect of PTMs on LLPS in silico, we extend our transferable coarse-grained model of intrinsically disordered proteins to include phosphorylated and acetylated amino acids. Using the parameters for modified amino acids available for fixed-charge atomistic force fields, we parameterize the size and atomistic hydropathy of the coarse-grained-modified amino acid beads and, hence, the interactions between the modified and natural amino acids. We then elucidate how the number and position of phosphorylated and acetylated residues alter the protein's single-chain compactness and its propensity to phase separate. We show that both the number and the position of phosphorylated threonines/serines or acetylated lysines can serve as a molecular on/off switch for phase separation in the well-studied disordered regions of Fused in Sarcoma (FUS) and DDX3X, respectively. We also compare modified residues to their commonly used PTM mimics for their impact on chain properties. Importantly, we show that the model can predict and capture experimentally measured differences in the phase behavior for position-specific modifications, showing that the position of modifications can dictate phase separation. In sum, this model will be useful for studying LLPS of post-translationally modified intrinsically disordered proteins and predicting how modifications control phase behavior with position-specific resolution.
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Affiliation(s)
| | - Nina Jovic
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania
| | - Gregory L Dignon
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania; Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, New York
| | - Young C Kim
- Center for Materials Physics and Technology, U.S. Naval Research Laboratory, Washington D.C
| | - Nicolas L Fawzi
- Department of Molecular Pharmacology, Physiology, and Biotechnology; Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, Rhode Island.
| | - Jeetain Mittal
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania.
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13
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Abstract
Stress granules (SGs) and processing bodies (PBs) are membraneless ribonucleoprotein-based cellular compartments that assemble in response to stress. SGs and PBs form through liquid-liquid phase separation that is driven by high local concentrations of key proteins and RNAs, both of which dynamically shuttle between the granules and the cytoplasm. SGs uniquely contain certain translation initiation factors and PBs are uniquely enriched with factors related to mRNA degradation and decay, although recent analyses reveal much broader protein commonality between these granules. Despite detailed knowledge of their composition and dynamics, the function of SGs and PBs remains poorly understood. Both, however, contain mRNAs, implicating their assembly in the regulation of RNA metabolism. SGs may also serve as hubs that rewire signaling events during stress. By contrast, PBs may constitute RNA storage centers, independent of mRNA decay. The aberrant assembly or disassembly of these granules has pathological implications in cancer, viral infection and neurodegeneration. Here, we review the current concepts regarding the formation, composition, dynamics, function and involvement in disease of SGs and PBs.
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Affiliation(s)
- Claire L Riggs
- Division of Rheumatology, Immunity, and Inflammation, Brigham and Women's Hospital, Harvard University, Boston, MA 02115, USA
| | - Nancy Kedersha
- Brigham and Woman's Hospital/Harvard Medical School, Harvard University, Boston, MA 02115, USA
| | - Pavel Ivanov
- Division of Rheumatology, Immunity, and Inflammation, Brigham and Women's Hospital, Harvard University, Boston, MA 02115, USA
| | - Paul Anderson
- Division of Rheumatology, Immunity, and Inflammation, Brigham and Women's Hospital, Harvard University, Boston, MA 02115, USA
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14
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Räsch F, Weber R, Izaurralde E, Igreja C. 4E-T-bound mRNAs are stored in a silenced and deadenylated form. Genes Dev 2020; 34:847-860. [PMID: 32354837 PMCID: PMC7263148 DOI: 10.1101/gad.336073.119] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 04/02/2020] [Indexed: 12/20/2022]
Abstract
Human 4E-T is an eIF4E-binding protein (4E-BP) present in processing (P)-bodies that represses translation and regulates decay of mRNAs destabilized by AU-rich elements and microRNAs (miRNAs). However, the underlying regulatory mechanisms are still unclear. Here, we show that upon mRNA binding 4E-T represses translation and promotes deadenylation via the recruitment of the CCR4-NOT deadenylase complex. The interaction with CCR4-NOT is mediated by previously uncharacterized sites in the middle region of 4E-T. Importantly, mRNA decapping and decay are inhibited by 4E-T and the deadenylated target is stored in a repressed form. Inhibition of mRNA decapping requires the interaction of 4E-T with the cap-binding proteins eIF4E/4EHP. We further show that regulation of decapping by 4E-T participates in mRNA repression by the miRNA effector protein TNRC6B and that 4E-T overexpression interferes with tristetraprolin (TTP)- and NOT1-mediated mRNA decay. Thus, we postulate that 4E-T modulates 5'-to-3' decay by swapping the fate of a deadenylated mRNA from complete degradation to storage. Our results provide insight into the mechanism of mRNA storage that controls localized translation and mRNA stability in P-bodies.
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Affiliation(s)
- Felix Räsch
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
| | - Ramona Weber
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
| | - Elisa Izaurralde
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
| | - Cátia Igreja
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
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15
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Mishra RK, Datey A, Hussain T. mRNA Recruiting eIF4 Factors Involved in Protein Synthesis and Its Regulation. Biochemistry 2019; 59:34-46. [DOI: 10.1021/acs.biochem.9b00788] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Rishi Kumar Mishra
- Department of Molecular Reproduction, Development and Genetics, Division of Biological Sciences, Indian Institute of Science, Bangalore 560012, India
| | - Ayushi Datey
- Department of Molecular Reproduction, Development and Genetics, Division of Biological Sciences, Indian Institute of Science, Bangalore 560012, India
| | - Tanweer Hussain
- Department of Molecular Reproduction, Development and Genetics, Division of Biological Sciences, Indian Institute of Science, Bangalore 560012, India
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16
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Owen I, Shewmaker F. The Role of Post-Translational Modifications in the Phase Transitions of Intrinsically Disordered Proteins. Int J Mol Sci 2019; 20:ijms20215501. [PMID: 31694155 PMCID: PMC6861982 DOI: 10.3390/ijms20215501] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/01/2019] [Accepted: 11/02/2019] [Indexed: 12/23/2022] Open
Abstract
Advances in genomics and proteomics have revealed eukaryotic proteomes to be highly abundant in intrinsically disordered proteins that are susceptible to diverse post-translational modifications. Intrinsically disordered regions are critical to the liquid-liquid phase separation that facilitates specialized cellular functions. Here, we discuss how post-translational modifications of intrinsically disordered protein segments can regulate the molecular condensation of macromolecules into functional phase-separated complexes.
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17
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Tian L, Wu C, Wen G, Li C. Transcriptional responses of LSm14A after infection of blue eggshell layers with Newcastle disease viruses. J Vet Med Sci 2019; 81:1468-1474. [PMID: 31534060 PMCID: PMC6863722 DOI: 10.1292/jvms.19-0125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
LSm14A is a key innate immunity component of processing body (P-body) that mediates
interferon-β (IFN-β) signaling by viral RNA. This is the first study to report chicken
LSm14A (cLSm14A) cloning from blue eggshell layer, high
tibia and frizzle chickens. The cLSm14A gene, encoding 461
amino acids, is highly homologous in the three types of chickens. The cLSm14A was
extensively expressed in several tissues. The transcriptional level of cLSm14A was
significantly increased in various stages of Newcastle disease virus (NDV) infection. In
HEK293 cells, full length cLSm14A from blue eggshell layer was localized
in the cytoplasm as dots. The results of this study indicated that cLSm14A is an important
sensor that mediates innate immunity in chicken against NDV infections.
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Affiliation(s)
- Lang Tian
- College of Animal Sciences, Preventive Veterinary Laboratory, Guizhou University, Guiyang 550025 China
| | - Changhua Wu
- Agricultural and Rural Bureau of Anshun City, Guizhou Province, Anshun 561000 China
| | - Guilan Wen
- College of Animal Sciences, Preventive Veterinary Laboratory, Guizhou University, Guiyang 550025 China
| | - Changhong Li
- College of Animal Sciences, Preventive Veterinary Laboratory, Guizhou University, Guiyang 550025 China
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18
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Poornima G, Mythili R, Nag P, Parbin S, Verma PK, Hussain T, Rajyaguru PI. RGG-motif self-association regulates eIF4G-binding translation repressor protein Scd6. RNA Biol 2019; 16:1215-1227. [PMID: 31157589 PMCID: PMC6693564 DOI: 10.1080/15476286.2019.1621623] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Regulation of mRNA translation plays a key role in the control of gene expression. Scd6, a conserved RGG-motif containing protein represses translation by binding to translation initiation factor eIF4G1. Here we report that Scd6 binds itself in RGG-motif dependent manner and self-association regulates its repression activity. Scd6 self-interaction competes with eIF4G1 binding and methylation of Scd6 RGG-motif by Hmt1 negatively affects self-association. Results pertaining to Sbp1 indicate that self-association could be a general feature of RGG-motif containing translation repressor proteins. Taken together, our study reveals a mechanism of regulation of eIF4G-binding RGG-motif translation repressors.
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Affiliation(s)
| | - Ravishankar Mythili
- a Department of Biochemistry, Indian Institute of Science , Bangalore , India.,b Department of Biology, University of Western Ontario , London , Canada
| | - Priyabrata Nag
- c Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science , Bangalore , India
| | - Sabnam Parbin
- a Department of Biochemistry, Indian Institute of Science , Bangalore , India
| | - Praveen Kumar Verma
- a Department of Biochemistry, Indian Institute of Science , Bangalore , India
| | - Tanweer Hussain
- c Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science , Bangalore , India
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19
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Hofweber M, Dormann D. Friend or foe-Post-translational modifications as regulators of phase separation and RNP granule dynamics. J Biol Chem 2018; 294:7137-7150. [PMID: 30587571 DOI: 10.1074/jbc.tm118.001189] [Citation(s) in RCA: 227] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Ribonucleoprotein (RNP) granules are membrane-less organelles consisting of RNA-binding proteins (RBPs) and RNA. RNA granules form through liquid-liquid phase separation (LLPS), whereby weak promiscuous interactions among RBPs and/or RNAs create a dense network of interacting macromolecules and drive the phase separation. Post-translational modifications (PTMs) of RBPs have emerged as important regulators of LLPS and RNP granule dynamics, as they can directly weaken or enhance the multivalent interactions between phase-separating macromolecules or can recruit or exclude certain macromolecules into or from condensates. Here, we review recent insights into how PTMs regulate phase separation and RNP granule dynamics, in particular arginine (Arg)-methylation and phosphorylation. We discuss how these PTMs regulate the phase behavior of prototypical RBPs and how, as "friend or foe," they might influence the assembly, disassembly, or material properties of cellular RNP granules, such as stress granules or amyloid-like condensates. We particularly highlight how PTMs control the phase separation and aggregation behavior of disease-linked RBPs. We also review how disruptions of PTMs might be involved in aberrant phase transitions and the formation of amyloid-like protein aggregates as observed in neurodegenerative diseases.
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Affiliation(s)
- Mario Hofweber
- From the BioMedical Center, Cell Biology, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 9, 82152 Planegg-Martinsried.,the Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, and
| | - Dorothee Dormann
- From the BioMedical Center, Cell Biology, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 9, 82152 Planegg-Martinsried, .,the Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, and.,the Munich Cluster for Systems Neurology (SyNergy), Feodor-Lynen-Strasse 17, 81377 Munich, Germany
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20
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Trypanosoma brucei PRMT1 Is a Nucleic Acid Binding Protein with a Role in Energy Metabolism and the Starvation Stress Response. mBio 2018; 9:mBio.02430-18. [PMID: 30563898 PMCID: PMC6299225 DOI: 10.1128/mbio.02430-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In Trypanosoma brucei and related kinetoplastid parasites, transcription of protein coding genes is largely unregulated. Rather, mRNA binding proteins, which impact processes such as transcript stability and translation efficiency, are the predominant regulators of gene expression. Arginine methylation is a posttranslational modification that preferentially targets RNA binding proteins and is, therefore, likely to have a substantial impact on T. brucei biology. The data presented here demonstrate that cells depleted of T. brucei PRMT1 (TbPRMT1), a major type I protein arginine methyltransferase, exhibit decreased virulence in an animal model. To understand the basis of this phenotype, quantitative global proteomics was employed to measure protein steady-state levels in cells lacking TbPRMT1. The approach revealed striking changes in proteins involved in energy metabolism. Most prominent were a decrease in glycolytic enzyme abundance and an increase in proline degradation pathway components, changes that resemble the metabolic remodeling that occurs during T. brucei life cycle progression. The work describes several RNA binding proteins whose association with mRNA was altered in TbPRMT1-depleted cells, and a large number of TbPRMT1-interacting proteins, thereby highlighting potential TbPRMT1 substrates. Many proteins involved in the T. brucei starvation stress response were found to interact with TbPRMT1, prompting analysis of the response of TbPRMT1-depleted cells to nutrient deprivation. Indeed, depletion of TbPRMT1 strongly hinders the ability of T. brucei to form cytoplasmic mRNA granules under starvation conditions. Finally, this work shows that TbPRMT1 itself binds nucleic acids in vitro and in vivo, a feature completely novel to protein arginine methyltransferases.IMPORTANCE Trypanosoma brucei infection causes human African trypanosomiasis, also known as sleeping sickness, a disease with a nearly 100% fatality rate when untreated. Current drugs are expensive, toxic, and highly impractical to administer, prompting the community to explore various unique aspects of T. brucei biology in search of better treatments. In this study, we identified the protein arginine methyltransferase (PRMT), TbPRMT1, as a factor that modulates numerous aspects of T. brucei biology. These include glycolysis and life cycle progression signaling, both of which are being intensely researched toward identification of potential drug targets. Our data will aid research in those fields. Furthermore, we demonstrate for the first time a direct association of a PRMT with nucleic acids, a finding we believe could translate to other organisms, including humans, thereby impacting research in fields as distant as human cancer biology and immune response modulation.
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21
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Chong PA, Vernon RM, Forman-Kay JD. RGG/RG Motif Regions in RNA Binding and Phase Separation. J Mol Biol 2018; 430:4650-4665. [PMID: 29913160 DOI: 10.1016/j.jmb.2018.06.014] [Citation(s) in RCA: 239] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/02/2018] [Accepted: 06/06/2018] [Indexed: 12/29/2022]
Abstract
RGG/RG motifs are RNA binding segments found in many proteins that can partition into membraneless organelles. They occur in the context of low-complexity disordered regions and often in multiple copies. Although short RGG/RG-containing regions can sometimes form high-affinity interactions with RNA structures, multiple RGG/RG repeats are generally required for high-affinity binding, suggestive of the dynamic, multivalent interactions that are thought to underlie phase separation in formation of cellular membraneless organelles. Arginine can interact with nucleotide bases via hydrogen bonding and π-stacking; thus, nucleotide conformers that provide access to the bases provide enhanced opportunities for RGG interactions. Methylation of RGG/RG regions, which is accomplished by protein arginine methyltransferase enzymes, occurs to different degrees in different cell types and may regulate the behavior of proteins containing these regions.
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Affiliation(s)
- P Andrew Chong
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - Robert M Vernon
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - Julie D Forman-Kay
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada; Department of Biochemistry, University of Toronto, Toronto, ON, Canada.
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22
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Standart N, Weil D. P-Bodies: Cytosolic Droplets for Coordinated mRNA Storage. Trends Genet 2018; 34:612-626. [PMID: 29908710 DOI: 10.1016/j.tig.2018.05.005] [Citation(s) in RCA: 140] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 05/14/2018] [Accepted: 05/17/2018] [Indexed: 12/21/2022]
Abstract
P-bodies (PBs) are cytosolic RNP granules that are conserved among eukaryotic organisms. In the past few years, major progress has been made in understanding the biochemical and biophysical mechanisms that lead to their formation. However, whether they play a role in mRNA storage or decay remains actively debated. P-bodies were recently isolated from human cells by a novel fluorescence-activated particle sorting (FAPS) approach that enabled the characterization of their protein and RNA content, providing new insights into their function. Together with recent innovative imaging studies, these new data show that mammalian PBs are primarily involved not in RNA decay but rather in the coordinated storage of mRNAs encoding regulatory functions. These small cytoplasmic droplets could thus be important for cell adaptation to the environment.
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Affiliation(s)
- Nancy Standart
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Dominique Weil
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine (IBPS), Laboratoire de Biologie du Développement, F-75005 Paris, France.
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23
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Roy D, Rajyaguru PI. Suppressor of clathrin deficiency (Scd6)-An emerging RGG-motif translation repressor. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 9:e1479. [DOI: 10.1002/wrna.1479] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 03/07/2018] [Accepted: 03/07/2018] [Indexed: 12/15/2022]
Affiliation(s)
- Debadrita Roy
- Department of Biochemistry; Indian Institute of Science; Bangalore India
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24
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Matsumoto K, Kose S, Kuwahara I, Yoshimura M, Imamoto N, Yoshida M. Y-box protein-associated acidic protein (YBAP1/C1QBP) affects the localization and cytoplasmic functions of YB-1. Sci Rep 2018; 8:6198. [PMID: 29670170 PMCID: PMC5906478 DOI: 10.1038/s41598-018-24401-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 03/26/2018] [Indexed: 01/07/2023] Open
Abstract
The Y-box proteins are multifunctional nucleic acid-binding proteins involved in various aspects of gene regulation. The founding member of the Y-box protein family, YB-1, functions as a transcription factor as well as a principal component of messenger ribonucleoprotein particles (mRNPs) in somatic cells. The nuclear level of YB-1 is well correlated with poor prognosis in many human cancers. Previously, we showed that a Y-box protein–associated acidic protein, YBAP1, which is identical to complement component 1, q subcomponent-binding protein (C1QBP, also called gC1qR, hyaluronan-binding protein 1 [HABP1] or ASF/SF2-associated protein p32), relieves translational repression by YB-1. Here we show that the nuclear localization of YB-1 harboring a point mutation in the cold shock domain was inhibited when co-expressed with YBAP1, whereas cytoplasmic accumulation of the wild-type YB-1 was not affected. We showed that YBAP1 inhibited the interaction between YB-1 and transportin 1. In the cytoplasm, YBAP1 affected the accumulation of YB-1 to processing bodies (P-bodies) and partially abrogated the mRNA stabilization by YB-1. Our results, indicating that YBAP1/C1QBP regulates the nucleo-cytoplasmic distribution of YB-1 and its cytoplasmic functions, are consistent with a model that YBAP1/C1QBP acts as an mRNP remodeling factor.
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Affiliation(s)
- Ken Matsumoto
- Chemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, RIKEN, Wako, Saitama, Japan. .,PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan. .,Molecular Entomology Laboratory, RIKEN, Wako, Saitama, Japan.
| | - Shingo Kose
- Cellular Dynamics Laboratory, RIKEN Cluster for Pioneering Research (CPR), RIKEN, Wako, Saitama, Japan
| | - Iku Kuwahara
- Molecular Entomology Laboratory, RIKEN, Wako, Saitama, Japan
| | - Mami Yoshimura
- Molecular Entomology Laboratory, RIKEN, Wako, Saitama, Japan
| | - Naoko Imamoto
- Cellular Dynamics Laboratory, RIKEN Cluster for Pioneering Research (CPR), RIKEN, Wako, Saitama, Japan
| | - Minoru Yoshida
- Chemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, RIKEN, Wako, Saitama, Japan
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25
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Brandmann T, Fakim H, Padamsi Z, Youn JY, Gingras AC, Fabian MR, Jinek M. Molecular architecture of LSM14 interactions involved in the assembly of mRNA silencing complexes. EMBO J 2018; 37:embj.201797869. [PMID: 29510985 DOI: 10.15252/embj.201797869] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 01/19/2018] [Accepted: 01/21/2018] [Indexed: 11/09/2022] Open
Abstract
The LSM domain-containing protein LSM14/Rap55 plays a role in mRNA decapping, translational repression, and RNA granule (P-body) assembly. How LSM14 interacts with the mRNA silencing machinery, including the eIF4E-binding protein 4E-T and the DEAD-box helicase DDX6, is poorly understood. Here we report the crystal structure of the LSM domain of LSM14 bound to a highly conserved C-terminal fragment of 4E-T. The 4E-T C-terminus forms a bi-partite motif that wraps around the N-terminal LSM domain of LSM14. We also determined the crystal structure of LSM14 bound to the C-terminal RecA-like domain of DDX6. LSM14 binds DDX6 via a unique non-contiguous motif with distinct directionality as compared to other DDX6-interacting proteins. Together with mutational and proteomic studies, the LSM14-DDX6 structure reveals that LSM14 has adopted a divergent mode of binding DDX6 in order to support the formation of mRNA silencing complexes and P-body assembly.
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Affiliation(s)
- Tobias Brandmann
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Hana Fakim
- Department of Oncology, McGill University, Montreal, QC, Canada.,Segal Cancer Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada
| | - Zoya Padamsi
- Department of Oncology, McGill University, Montreal, QC, Canada.,Segal Cancer Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada
| | - Ji-Young Youn
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Marc R Fabian
- Department of Oncology, McGill University, Montreal, QC, Canada .,Segal Cancer Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada
| | - Martin Jinek
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
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26
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Hua K, Li H, Chen H, Foda MF, Luo R, Jin H. Functional characterization of duck LSm14A in IFN-β induction. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 76:255-261. [PMID: 28666650 DOI: 10.1016/j.dci.2017.06.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 06/24/2017] [Accepted: 06/26/2017] [Indexed: 06/07/2023]
Abstract
Human LSm14A is a key component of processing body (P-body) assembly that mediates interferon-β (IFN-β) production by sensing viral RNA or DNA. To the best of our knowledge, we are the first to report duck LSm14A (duLSm14A) cloning from duck embryo fibroblasts (DEFs). Full-length duLSm14A encoded 461 amino acids and was highly homologous with chicken and swan goose sequences. More interestingly, the duLSm14A mRNA was extensively expressed in all the studied tissues. In DEFs, duLSm14A was localized in the cytoplasm as P-body-like dots. Expression of duLSm14A induced IFN-β through the activation of interferon regulatory factor-1 and nuclear factor-κB in DEFs. Furthermore, knockdown of duLSm14A by small interfering RNA notably decreased poly(I:C)- or duck reovirus-induced IFN-β production. The present study results indicate that the duLSm14A is an essential sensor that mediates duck innate immunity against viral infections.
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Affiliation(s)
- Kexin Hua
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Huilin Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Mohamed Frahat Foda
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; Department of Biochemistry, Faculty of Agriculture, Benha University, Moshtohor, Toukh 13736, Egypt
| | - Rui Luo
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Hui Jin
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
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27
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Lien PTK, Izumikawa K, Muroi K, Irie K, Suda Y, Irie K. Analysis of the Physiological Activities of Scd6 through Its Interaction with Hmt1. PLoS One 2016; 11:e0164773. [PMID: 27776129 PMCID: PMC5077174 DOI: 10.1371/journal.pone.0164773] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 09/30/2016] [Indexed: 01/26/2023] Open
Abstract
Scd6, a yeast homologue of human RAP55, is a component of messenger ribonucleoproteins (mRNPs) that repress translation by binding to translation initiation factors, and also is a decapping activator along with the binding partners Edc3 and Dhh1. Herein, we report that Scd6 is a substrate of the intrinsic protein arginine methyltransferase, Hmt1, in budding yeast Saccharomyces cerevisiae. Mass spectrometric analysis revealed that several arginine residues within the Scd6 RGG motif, which is important for mRNA binding, were methylated in Hmt1 dependent manner. Under stress conditions such as glucose starvation, Scd6 localized to cytoplasmic processing bodies (P-bodies) wherein translationally repressed mRNPs and untranslated mRNAs accumulate. Localization of Scd6 to P-bodies was impaired in hmt1 deletion mutant and in the presence of methylation-deficient substitution of Scd6. In addition, deletion of scd6 and dhh1 led to severe synthetic growth defect at high temperature. Methylation-deficient mutation of Scd6 suppressed the phenotypic defects of scd6 dhh1 double mutant, whereas methylation-mimic mutation did not, suggesting that the arginine methylation might negatively regulate Scd6 function relating to Dhh1. Therefore, the present data suggest that Hmt1-based arginine methylation is required for Scd6 localization and function.
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Affiliation(s)
- Pham Thi Kim Lien
- Department of Molecular Cell Biology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Keiichi Izumikawa
- Global Innovation Research Organization, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan
| | - Kei Muroi
- Department of Molecular Cell Biology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Kaoru Irie
- Department of Molecular Cell Biology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yasuyuki Suda
- Department of Molecular Cell Biology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Live Cell Super-resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama, Japan
- * E-mail:
| | - Kenji Irie
- Department of Molecular Cell Biology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
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28
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Poornima G, Shah S, Vignesh V, Parker R, Rajyaguru PI. Arginine methylation promotes translation repression activity of eIF4G-binding protein, Scd6. Nucleic Acids Res 2016; 44:9358-9368. [PMID: 27613419 PMCID: PMC5100564 DOI: 10.1093/nar/gkw762] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Accepted: 08/20/2016] [Indexed: 12/14/2022] Open
Abstract
Regulation of translation plays a critical role in determining mRNA fate. A new role was recently reported for a subset of RGG-motif proteins in repressing translation initiation by binding eIF4G1. However the signaling mechanism(s) that leads to spatial and temporal regulation of repression activity of RGG-motif proteins remains unknown. Here we report the role of arginine methylation in regulation of repression activity of Scd6, a conserved RGG-motif protein. We demonstrate that Scd6 gets arginine methylated at its RGG-motif and Hmt1 plays an important role in its methylation. We identify specific methylated arginine residues in the Scd6 RGG-motif in vivo We provide evidence that methylation augments Scd6 repression activity. Arginine methylation defective (AMD) mutant of Scd6 rescues the growth defect caused by overexpression of Scd6, a feature of translation repressors in general. Live-cell imaging of the AMD mutant revealed that it is defective in inducing formation of stress granules. Live-cell imaging and pull-down results indicate that it fails to bind eIF4G1 efficiently. Consistent with these results, a strain lacking Hmt1 is also defective in Scd6-eIF4G1 interaction. Our results establish that arginine methylation augments Scd6 repression activity by promoting eIF4G1-binding. We propose that arginine methylation of translation repressors with RGG-motif could be a general modulator of their repression activity.
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Affiliation(s)
- Gopalakrishna Poornima
- Department of Biochemistry, Indian Institute of Science, C V Raman Road, Bangalore 560012, India
| | - Shanaya Shah
- Department of Biochemistry, Indian Institute of Science, C V Raman Road, Bangalore 560012, India
| | | | - Roy Parker
- Department of Chemistry and Biochemistry, University of Colorado, 596 UCB, Boulder, CO 80309, USA
| | - Purusharth I Rajyaguru
- Department of Biochemistry, Indian Institute of Science, C V Raman Road, Bangalore 560012, India
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29
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Poblete-Durán N, Prades-Pérez Y, Vera-Otarola J, Soto-Rifo R, Valiente-Echeverría F. Who Regulates Whom? An Overview of RNA Granules and Viral Infections. Viruses 2016; 8:v8070180. [PMID: 27367717 PMCID: PMC4974515 DOI: 10.3390/v8070180] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/10/2016] [Accepted: 06/21/2016] [Indexed: 12/22/2022] Open
Abstract
After viral infection, host cells respond by mounting an anti-viral stress response in order to create a hostile atmosphere for viral replication, leading to the shut-off of mRNA translation (protein synthesis) and the assembly of RNA granules. Two of these RNA granules have been well characterized in yeast and mammalian cells, stress granules (SGs), which are translationally silent sites of RNA triage and processing bodies (PBs), which are involved in mRNA degradation. This review discusses the role of these RNA granules in the evasion of anti-viral stress responses through virus-induced remodeling of cellular ribonucleoproteins (RNPs).
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Affiliation(s)
- Natalia Poblete-Durán
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Independencia 1027, Santiago, 8389100, Chile.
| | - Yara Prades-Pérez
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Independencia 1027, Santiago, 8389100, Chile.
| | - Jorge Vera-Otarola
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago 8330024, Chile.
| | - Ricardo Soto-Rifo
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Independencia 1027, Santiago, 8389100, Chile.
| | - Fernando Valiente-Echeverría
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Independencia 1027, Santiago, 8389100, Chile.
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30
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Zhang L, Tran NT, Su H, Wang R, Lu Y, Tang H, Aoyagi S, Guo A, Khodadadi-Jamayran A, Zhou D, Qian K, Hricik T, Côté J, Han X, Zhou W, Laha S, Abdel-Wahab O, Levine RL, Raffel G, Liu Y, Chen D, Li H, Townes T, Wang H, Deng H, Zheng YG, Leslie C, Luo M, Zhao X. Cross-talk between PRMT1-mediated methylation and ubiquitylation on RBM15 controls RNA splicing. eLife 2015; 4:07938. [PMID: 26575292 PMCID: PMC4775220 DOI: 10.7554/elife.07938] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Accepted: 11/16/2015] [Indexed: 12/24/2022] Open
Abstract
RBM15, an RNA binding protein, determines cell-fate specification of many tissues including blood. We demonstrate that RBM15 is methylated by protein arginine methyltransferase 1 (PRMT1) at residue R578, leading to its degradation via ubiquitylation by an E3 ligase (CNOT4). Overexpression of PRMT1 in acute megakaryocytic leukemia cell lines blocks megakaryocyte terminal differentiation by downregulation of RBM15 protein level. Restoring RBM15 protein level rescues megakaryocyte terminal differentiation blocked by PRMT1 overexpression. At the molecular level, RBM15 binds to pre-messenger RNA intronic regions of genes important for megakaryopoiesis such as GATA1, RUNX1, TAL1 and c-MPL. Furthermore, preferential binding of RBM15 to specific intronic regions recruits the splicing factor SF3B1 to the same sites for alternative splicing. Therefore, PRMT1 regulates alternative RNA splicing via reducing RBM15 protein concentration. Targeting PRMT1 may be a curative therapy to restore megakaryocyte differentiation for acute megakaryocytic leukemia. DOI:http://dx.doi.org/10.7554/eLife.07938.001 The many different cell types in an adult animal all develop from a single fertilized egg. The development of cells into more specialized cell types is called ‘differentiation’. Proteins and other molecules from both inside and outside of the cells regulate the differentiation process. RNA is a molecule that is similar to DNA, and performs several important roles inside cells. Perhaps most importantly, RNA molecules act as messengers and carry genetic instructions during gene expression. RBM15 is an RNA-binding protein that is found throughout nature, and is involved in a number of developmental processes. Previous research has linked the incorrect control of RBM15 with an increased risk of certain cancers, including megakaryocytic leukemia. However, it is not clear what role RNA-binding proteins such as RBM15 play during differentiation. Now, Zhang, Tran, Su et al. have investigated the role of RBM15 during the development of large cells found in human bone marrow (called megakaryocytes). First, the experiments demonstrated that an enzyme called PRMT1 modifies RBM15. This enzyme adds a chemical mark called a methyl group at a specific site (an arginine amino acid) on the RNA-binding protein. Next, Zhang, Tran, Su et al. showed that the addition of this methyl group earmarks RBM15 for destruction. This means that an increase in PRMT1 levels reduces the amount of RBM15 in cells, while decreases in PRMT1 have the opposite effect. Further experiments showed that RBM15 normally processes the RNA messengers that carry the genetic instructions needed for the differentiation of bone marrow cells. An excess of PRMT1 enzyme leads to a lack of this RNA-binding protein. This in turn interferes with the differentiation process, and can contribute to the development of cancers such as megakaryocytic leukemia. Future work will therefore explore whether targeting PRMT1 with drugs could represent an effective treatment for these kinds of cancers. DOI:http://dx.doi.org/10.7554/eLife.07938.002
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Affiliation(s)
- Li Zhang
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, The University of Alabama at Birmingham, Birmingham, United States
| | - Ngoc-Tung Tran
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, The University of Alabama at Birmingham, Birmingham, United States
| | - Hairui Su
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, The University of Alabama at Birmingham, Birmingham, United States
| | - Rui Wang
- Program of Molecular Pharmacology, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Yuheng Lu
- Computational Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Haiping Tang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Sayura Aoyagi
- Cell Signaling Technology, Inc., Danvers, United States
| | - Ailan Guo
- Cell Signaling Technology, Inc., Danvers, United States
| | - Alireza Khodadadi-Jamayran
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, The University of Alabama at Birmingham, Birmingham, United States
| | - Dewang Zhou
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, The University of Alabama at Birmingham, Birmingham, United States
| | - Kun Qian
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, United States
| | - Todd Hricik
- Human Oncology and Pathogenesis Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Jocelyn Côté
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Xiaosi Han
- Department of Neurology, Comprehensive Cancer Center, The University of Alabama at Birmingham, Birmingham, United States
| | - Wenping Zhou
- Department of Internal Medicine, Zhengzhou - Henan Cancer Hospital, Zhengzhou, China
| | - Suparna Laha
- Division of Hematology and Oncology, University of Massachusetts Medical School, Worcester, United States
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Ross L Levine
- Human Oncology and Pathogenesis Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Glen Raffel
- Division of Hematology and Oncology, University of Massachusetts Medical School, Worcester, United States
| | - Yanyan Liu
- Department of Internal Medicine, Zhengzhou - Henan Cancer Hospital, Zhengzhou, China
| | - Dongquan Chen
- Division of Preventive Medicine, The University of Alabama at Birmingham, Birmingham, United States
| | - Haitao Li
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Tim Townes
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, The University of Alabama at Birmingham, Birmingham, United States
| | - Hengbin Wang
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, The University of Alabama at Birmingham, Birmingham, United States
| | - Haiteng Deng
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Y George Zheng
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, United States
| | - Christina Leslie
- Computational Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Minkui Luo
- Program of Molecular Pharmacology, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Xinyang Zhao
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, The University of Alabama at Birmingham, Birmingham, United States
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Ladomery M, Sommerville J. The Scd6/Lsm14 protein xRAPB has properties different from RAP55 in selecting mRNA for early translation or intracellular distribution in Xenopus oocytes. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2015; 1849:1363-73. [PMID: 26455898 DOI: 10.1016/j.bbagrm.2015.10.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 10/03/2015] [Accepted: 10/05/2015] [Indexed: 11/17/2022]
Abstract
Oocytes accumulate mRNAs in the form of maternal ribonucleoprotein (RNP) particles, the protein components of which determine the location and stability of individual mRNAs prior to translation. Scd6/Lsm14 proteins, typified by RAP55, function in a wide range of eukaryotes in repressing translation and relocating mRNPs to processing bodies and stress granules. In Xenopus laevis, the RAP55 orthologue xRAPA fulfils these functions. Here we describe the properties of a variant of xRAPA, xRAPB, which is a member of the Lsm14B group. xRAPB differs from xRAPA in various respects: it is expressed at high concentration earlier in oogenesis; it interacts specifically with the DDX6 helicase Xp54; it is detected in polysomes and stalled translation initiation complexes; its over-expression leads to selective binding to translatable mRNA species without evidence of translation repression or mRNA degradation. Since both Xp54 and xRAPA are repressors of translation, activation appears to be effected through targeting of xRAPB/Xp54.
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Affiliation(s)
- Michael Ladomery
- Biomedical Sciences Research Complex, Biomolecular Sciences Building, University of St Andrews, North Haugh, St Andrews KY16 9TS, UK
| | - John Sommerville
- Biomedical Sciences Research Complex, Biomolecular Sciences Building, University of St Andrews, North Haugh, St Andrews KY16 9TS, UK.
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Kaehler C, Guenther A, Uhlich A, Krobitsch S. PRMT1-mediated arginine methylation controls ATXN2L localization. Exp Cell Res 2015; 334:114-25. [PMID: 25748791 DOI: 10.1016/j.yexcr.2015.02.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 02/20/2015] [Accepted: 02/25/2015] [Indexed: 01/02/2023]
Abstract
Arginine methylation is a posttranslational modification that is of importance in diverse cellular processes. Recent proteomic mass spectrometry studies reported arginine methylation of ataxin-2-like (ATXN2L), the paralog of ataxin-2, a protein that is implicated in the neurodegenerative disorder spinocerebellar ataxia type 2. Here, we investigated the methylation state of ATXN2L and its significance for ATXN2L localization. We first confirmed that ATXN2L is asymmetrically dimethylated in vivo, and observed that the nuclear localization of ATXN2L is altered under methylation inhibition. We further discovered that ATXN2L associates with the protein arginine-N-methyltransferase 1 (PRMT1). Finally, we showed that neither mutation of the arginine-glycine-rich motifs of ATXN2L nor methylation inhibition alters ATXN2L localization to stress granules, suggesting that methylation of ATXN2L is probably not mandatory.
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Affiliation(s)
- Christian Kaehler
- Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany
| | - Anika Guenther
- Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany
| | - Anja Uhlich
- Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany
| | - Sylvia Krobitsch
- Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany.
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33
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Abstract
The storage of translationally inactive mRNAs in cytosolic granules enables cells to react flexibly to environmental changes. In eukaryotes, Scd6 (suppressor of clathrin deficiency 6)/Rap55 (RNA-associated protein 55), a member of the LSm14 (like-Sm14) family, is an important factor in the formation and activity of P-bodies, where mRNA decay factors accumulate, in stress granules that store mRNAs under adverse conditions and in granules that store developmentally regulated mRNAs. SCD6 from Trypanosoma brucei (TbSCD6) shares the same domain architecture as orthologous proteins in other organisms and is also present in cytosolic granules (equivalent to P-bodies). We show that TbSCD6 is a general repressor of translation and that its depletion by RNAi results in a global increase in protein synthesis. With few exceptions, the steady-state levels of proteins are unchanged. TbSCD6 is not required for the formation of starvation-induced granules in trypanosomes, and unlike Scd6 from yeast, Plasmodium and all multicellular organisms analysed to date, it does not form a complex with the helicase Dhh1 (DExD/H-box helicase 1). In common with Xenopus laevis RAP55, TbSCD6 co-purifies with two arginine methyltransferases; moreover, TbSCD6 itself is methylated on three arginine residues. Finally, a detailed analysis identified roles for the Lsm and N-rich domains in both protein localization and translational repression.
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34
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Masuda A, Dohmae N. Examination of an absolute quantity of less than a hundred nanograms of proteins by amino acid analysis. Anal Bioanal Chem 2013; 405:8073-81. [PMID: 23719935 PMCID: PMC3777156 DOI: 10.1007/s00216-013-7056-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/14/2013] [Accepted: 05/08/2013] [Indexed: 11/28/2022]
Abstract
We developed an ultra-sensitive method of amino acid analysis (AAA) for the absolute quantification of less than 100 ng of proteins, in solution or on polyvinylidene difluoride (PVDF) membranes using an oxygen-free chamber for protein hydrolysis. We used a pre-label method with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate for fluorescence detection, ion-pair chromatography with a reversed-phase column, and an ultra-high-pressure high-performance liquid chromatography. We optimized both handling- and instrument-dependent factors for accurate quantification and showed that the least amount of proteins to quantify was determined by handling accuracy rather than instrumental limit for quantification which was 0.6 fmol/amino acid. As a new evaluation method for the handling accuracy, we adopted the protein identification by the obtained amino acid compositions by AAA and the Swiss-Prot database search without the restriction of species. As a result, the least amount of starting material for AAA was 16 ng (0.24 pmol) for a solution of bovine serum albumin (BSA), 33 ng (0.50 pmol) for BSA on a PVDF membrane, and 44 ng (0.15 pmol) for thyroglobulin on a PVDF membrane. These results demonstrate that the ultra-sensitive AAA developed in this study is feasible for absolute quantification of biological significant protein. Specification of ultra-sensitive amino acid analysis ![]()
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Affiliation(s)
- Akiko Masuda
- Biomolecular Characterization Team, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 Japan
| | - Naoshi Dohmae
- Biomolecular Characterization Team, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 Japan
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Krüger T, Hofweber M, Kramer S. SCD6 induces ribonucleoprotein granule formation in trypanosomes in a translation-independent manner, regulated by its Lsm and RGG domains. Mol Biol Cell 2013; 24:2098-111. [PMID: 23676662 PMCID: PMC3694794 DOI: 10.1091/mbc.e13-01-0068] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Trypanosomes lack many core components of ribonucleoprotein (RNP) granules identified in yeast and humans (e.g., DCP1/2). This study provides evidence for SCD6 being the core RNP granule component in trypanosomes: overexpression induces granules independent of translation, and even when SCD6 is targeted to the nucleus. Granule type and granule number are dependent on the RGG domain. Ribonucleoprotein (RNP) granules are cytoplasmic, microscopically visible structures composed of RNA and protein with proposed functions in mRNA decay and storage. Trypanosomes have several types of RNP granules, but lack most of the granule core components identified in yeast and humans. The exception is SCD6/Rap55, which is essential for processing body (P-body) formation. In this study, we analyzed the role of trypanosome SCD6 in RNP granule formation. Upon overexpression, the majority of SCD6 aggregates to multiple granules enriched at the nuclear periphery that recruit both P-body and stress granule proteins, as well as mRNAs. Granule protein composition depends on granule distance to the nucleus. In contrast to findings in yeast and humans, granule formation does not correlate with translational repression and can also take place in the nucleus after nuclear targeting of SCD6. While the SCD6 Lsm domain alone is both necessary and sufficient for granule induction, the RGG motif determines granule type and number: the absence of an intact RGG motif results in the formation of fewer granules that resemble P-bodies. The differences in granule number remain after nuclear targeting, indicating translation-independent functions of the RGG domain. We propose that, in trypanosomes, a local increase in SCD6 concentration may be sufficient to induce granules by recruiting mRNA. Proteins that bind selectively to the RGG and/or Lsm domain of SCD6 could be responsible for regulating granule type and number.
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Affiliation(s)
- Timothy Krüger
- Lehrstuhl für Zell- und Entwicklungsbiologie, Biozentrum, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
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Lloyd RE. Regulation of stress granules and P-bodies during RNA virus infection. WILEY INTERDISCIPLINARY REVIEWS-RNA 2013; 4:317-31. [PMID: 23554219 PMCID: PMC3652661 DOI: 10.1002/wrna.1162] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
RNA granules are structures within cells that play major roles in gene expression and homeostasis. Two principle kinds of RNA granules are conserved from yeast to mammals: stress granules (SGs), which contain stalled translation initiation complexes, and processing bodies (P‐bodies, PBs), which are enriched with factors involved in RNA turnover. Since RNA granules are associated with silenced transcripts, viruses subvert RNA granule function for replicative advantages. This review, focusing on RNA viruses, discusses mechanisms that manipulate stress granules and P‐bodies to promote synthesis of viral proteins. Three main themes have emerged for how viruses manipulate RNA granules; (1) cleavage of key host factors, (2) control of protein kinase R (PKR) activation, and (3) redirecting RNA granule components for new or parallel roles in viral reproduction, at the same time disrupting RNA granules. Viruses utilize one or more of these routes to achieve robust and productive infection. WIREs RNA 2013, 4:317–331. doi: 10.1002/wrna.1162 This article is categorized under:
RNA in Disease and Development > RNA in Disease
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Affiliation(s)
- Richard E Lloyd
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA.
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37
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The NS1 protein of influenza A virus interacts with cellular processing bodies and stress granules through RNA-associated protein 55 (RAP55) during virus infection. J Virol 2012; 86:12695-707. [PMID: 22973032 DOI: 10.1128/jvi.00647-12] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The nonstructural protein (NS1) of influenza A virus performs multiple functions in the virus life cycle. Proteomic screening for cellular proteins which interact with NS1 identified the cellular protein RAP55, which is one of the components of cellular processing bodies (P-bodies) and stress granules. To verify whether NS1 interacts with cellular P-bodies, interactions between NS1, RAP55, and other P-body-associated proteins (Ago1, Ago2, and DCP1a) were confirmed using coimmunoprecipitation and cellular colocalization assays. Overexpression of RAP55 induced RAP55-associated stress granule formation and suppressed virus replication. Knockdown of RAP55 with small interfering RNA (siRNA) or expression of a dominant-negative mutant RAP55 protein with defective interaction with P-bodies blocked NS1 colocalization to P-bodies in cells. Expression of NS1 inhibited RAP55 expression and formation of RAP55-associated P-bodies/stress granules. The viral nucleoprotein (NP) was found to be targeted to stress granules in the absence of NS1 but localized to P-bodies when NS1 was coexpressed. Restriction of virus replication via P-bodies occurred in the early phases of infection, as the number of RAP55-associated P-bodies in cells diminished over the course of virus infection. NS1 interaction with RAP55-associated P-bodies/stress granules was associated with RNA binding and mediated via a protein kinase R (PKR)-interacting viral element. Mutations introduced into either RNA binding sites (R38 and K41) or PKR interaction sites (I123, M124, K126, and N127) caused NS1 proteins to lose the ability to interact with RAP55 and to inhibit stress granules. These results reveal an interplay between virus and host during virus replication in which NP is targeted to P-bodies/stress granules while NS1 counteracts this host restriction mechanism.
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YB-1 functions as a porter to lead influenza virus ribonucleoprotein complexes to microtubules. J Virol 2012; 86:11086-95. [PMID: 22855482 DOI: 10.1128/jvi.00453-12] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
De novo-synthesized RNAs are under the regulation of multiple posttranscriptional processes by a variety of RNA-binding proteins. The influenza virus genome consists of single-stranded RNAs and exists as viral ribonucleoprotein (vRNP) complexes. After the replication of vRNP in the nucleus, it is exported to the cytoplasm and then reaches the budding site beneath the cell surface in a process mediated by Rab11a-positive recycling endosomes along microtubules. However, the regulatory mechanisms of the postreplicational processes of vRNP are largely unknown. Here we identified, as a novel vRNP-interacting protein, Y-box-binding protein 1 (YB-1), a cellular protein that is involved in regulation of cellular transcription and translation. YB-1 translocated to the nucleus from the cytoplasm and accumulated in PML nuclear bodies in response to influenza virus infection. vRNP assembled into the exporting complexes with YB-1 at PML nuclear bodies. After nuclear export, using YB-1 knockdown cells and in vitro reconstituted systems, YB-1 was shown to be required for the interaction of vRNP exported from the nucleus with microtubules around the microtubule-organizing center (MTOC), where Rab11a-positive recycling endosomes were located. Further, we also found that YB-1 overexpression stimulates the production of progeny virions in an Rab11a-dependent manner. Taking these findings together, we propose that YB-1 is a porter that leads vRNP to microtubules from the nucleus and puts it into the vesicular trafficking system.
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