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Kang K, Sun C, Li H, Liu X, Deng J, Chen S, Zeng L, Chen J, Liu X, Kuang J, Xiang J, Cheng J, Liao X, Lin M, Zhang X, Zhan C, Liu S, Wang J, Niu Y, Liu C, Liang C, Zhu J, Liang S, Tang H, Gou D. N6-methyladenosine-driven miR-143/145-KLF4 circuit orchestrates the phenotypic switch of pulmonary artery smooth muscle cells. Cell Mol Life Sci 2024; 81:256. [PMID: 38866991 DOI: 10.1007/s00018-024-05304-1] [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: 10/09/2023] [Revised: 05/28/2024] [Accepted: 05/30/2024] [Indexed: 06/14/2024]
Abstract
Pulmonary hypertension (PH) is characterized by vascular remodeling predominantly driven by a phenotypic switching in pulmonary artery smooth muscle cells (PASMCs). However, the underlying mechanisms for this phenotypic alteration remain incompletely understood. Here, we identified that RNA methyltransferase METTL3 is significantly elevated in the lungs of hypoxic PH (HPH) mice and rats, as well as in the pulmonary arteries (PAs) of HPH rats. Targeted deletion of Mettl3 in smooth muscle cells exacerbated hemodynamic consequences of hypoxia-induced PH and accelerated pulmonary vascular remodeling in vivo. Additionally, the absence of METTL3 markedly induced phenotypic switching in PASMCs in vitro. Mechanistically, METTL3 depletion attenuated m6A modification and hindered the processing of pri-miR-143/145, leading to a downregulation of miR-143-3p and miR-145-5p. Inhibition of hnRNPA2B1, an m6A mediator involved in miRNA maturation, similarly resulted in a significant reduction of miR-143-3p and miR-145-5p. We demonstrated that miR-145-5p targets Krüppel-like factor 4 (KLF4) and miR-143-3p targets fascin actin-bundling protein 1 (FSCN1) in PASMCs. The decrease of miR-145-5p subsequently induced an upregulation of KLF4, which in turn suppressed miR-143/145 transcription, establishing a positive feedback circuit between KLF4 and miR-143/145. This regulatory circuit facilitates the persistent suppression of contractile marker genes, thereby sustaining PASMC phenotypic switch. Collectively, hypoxia-induced upregulation of METTL3, along with m6A mediated regulation of miR-143/145, might serve as a protective mechanism against phenotypic switch of PASMCs. Our results highlight a potential therapeutic strategy targeting m6A modified miR-143/145-KLF4 loop in the treatment of PH.
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Affiliation(s)
- Kang Kang
- Department of Biochemistry and Molecular Biology, Shenzhen University Medical School, Shenzhen, 518060, Guangdong, China
| | - Chuannan Sun
- Department of Biochemistry and Molecular Biology, Shenzhen University Medical School, Shenzhen, 518060, Guangdong, China
| | - Hui Li
- Department of Biochemistry and Molecular Biology, Shenzhen University Medical School, Shenzhen, 518060, Guangdong, China
| | - Xiaojia Liu
- Department of Biochemistry and Molecular Biology, Shenzhen University Medical School, Shenzhen, 518060, Guangdong, China
| | - Jingyuan Deng
- Department of Biochemistry and Molecular Biology, Shenzhen University Medical School, Shenzhen, 518060, Guangdong, China
| | - Silei Chen
- Department of Biochemistry and Molecular Biology, Shenzhen University Medical School, Shenzhen, 518060, Guangdong, China
| | - Le Zeng
- Shenzhen Key Laboratory of Microbial Genetic Engineering, Vascular Disease Research Center, College of Life Sciences and Oceanography, Guangdong Provincial Key Laboratory of Regional Immunity and Disease, Carson International Cancer Center, School of Medicine, Shenzhen University, Shenzhen, 518060, China
| | - Jiahao Chen
- Department of Biochemistry and Molecular Biology, Shenzhen University Medical School, Shenzhen, 518060, Guangdong, China
| | - Xinyi Liu
- Department of Biochemistry and Molecular Biology, Shenzhen University Medical School, Shenzhen, 518060, Guangdong, China
| | - Jiahao Kuang
- Department of Biochemistry and Molecular Biology, Shenzhen University Medical School, Shenzhen, 518060, Guangdong, China
| | - Jingjing Xiang
- Department of Biochemistry and Molecular Biology, Shenzhen University Medical School, Shenzhen, 518060, Guangdong, China
| | - Jingqian Cheng
- Department of Biochemistry and Molecular Biology, Shenzhen University Medical School, Shenzhen, 518060, Guangdong, China
| | - Xiaoyun Liao
- Shenzhen Key Laboratory of Microbial Genetic Engineering, Vascular Disease Research Center, College of Life Sciences and Oceanography, Guangdong Provincial Key Laboratory of Regional Immunity and Disease, Carson International Cancer Center, School of Medicine, Shenzhen University, Shenzhen, 518060, China
| | - Mujin Lin
- Department of Biochemistry and Molecular Biology, Shenzhen University Medical School, Shenzhen, 518060, Guangdong, China
| | - Xingshi Zhang
- Department of Biochemistry and Molecular Biology, Shenzhen University Medical School, Shenzhen, 518060, Guangdong, China
| | - Chuzhi Zhan
- Department of Biochemistry and Molecular Biology, Shenzhen University Medical School, Shenzhen, 518060, Guangdong, China
| | - Sisi Liu
- Department of Biochemistry and Molecular Biology, Shenzhen University Medical School, Shenzhen, 518060, Guangdong, China
| | - Jun Wang
- Shenzhen Key Laboratory of Microbial Genetic Engineering, Vascular Disease Research Center, College of Life Sciences and Oceanography, Guangdong Provincial Key Laboratory of Regional Immunity and Disease, Carson International Cancer Center, School of Medicine, Shenzhen University, Shenzhen, 518060, China
| | - Yanqin Niu
- Shenzhen Key Laboratory of Microbial Genetic Engineering, Vascular Disease Research Center, College of Life Sciences and Oceanography, Guangdong Provincial Key Laboratory of Regional Immunity and Disease, Carson International Cancer Center, School of Medicine, Shenzhen University, Shenzhen, 518060, China
| | - Cuilian Liu
- Shenzhen Key Laboratory of Microbial Genetic Engineering, Vascular Disease Research Center, College of Life Sciences and Oceanography, Guangdong Provincial Key Laboratory of Regional Immunity and Disease, Carson International Cancer Center, School of Medicine, Shenzhen University, Shenzhen, 518060, China
| | - Cai Liang
- Shenzhen Key Laboratory of Microbial Genetic Engineering, Vascular Disease Research Center, College of Life Sciences and Oceanography, Guangdong Provincial Key Laboratory of Regional Immunity and Disease, Carson International Cancer Center, School of Medicine, Shenzhen University, Shenzhen, 518060, China
| | - Jinsheng Zhu
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510120, Guangdong, China
| | - Shuxin Liang
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510120, Guangdong, China
| | - Haiyang Tang
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510120, Guangdong, China
| | - Deming Gou
- Shenzhen Key Laboratory of Microbial Genetic Engineering, Vascular Disease Research Center, College of Life Sciences and Oceanography, Guangdong Provincial Key Laboratory of Regional Immunity and Disease, Carson International Cancer Center, School of Medicine, Shenzhen University, Shenzhen, 518060, China.
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Joshua IM, Lin M, Mardjuki A, Mazzola A, Höfken T. A Protein-Protein Interaction Analysis Suggests a Wide Range of New Functions for the p21-Activated Kinase (PAK) Ste20. Int J Mol Sci 2023; 24:15916. [PMID: 37958899 PMCID: PMC10647699 DOI: 10.3390/ijms242115916] [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: 09/20/2023] [Revised: 10/25/2023] [Accepted: 10/30/2023] [Indexed: 11/15/2023] Open
Abstract
The p21-activated kinases (PAKs) are important signaling proteins. They contribute to a surprisingly wide range of cellular processes and play critical roles in a number of human diseases including cancer, neurological disorders and cardiac diseases. To get a better understanding of PAK functions, mechanisms and integration of various cellular activities, we screened for proteins that bind to the budding yeast PAK Ste20 as an example, using the split-ubiquitin technique. We identified 56 proteins, most of them not described previously as Ste20 interactors. The proteins fall into a small number of functional categories such as vesicle transport and translation. We analyzed the roles of Ste20 in glucose metabolism and gene expression further. Ste20 has a well-established role in the adaptation to changing environmental conditions through the stimulation of mitogen-activated protein kinase (MAPK) pathways which eventually leads to transcription factor activation. This includes filamentous growth, an adaptation to nutrient depletion. Here we show that Ste20 also induces filamentous growth through interaction with nuclear proteins such as Sac3, Ctk1 and Hmt1, key regulators of gene expression. Combining our observations and the data published by others, we suggest that Ste20 has several new and unexpected functions.
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Affiliation(s)
| | - Meng Lin
- Institute of Biochemistry, Kiel University, 24118 Kiel, Germany
| | - Ariestia Mardjuki
- Division of Biosciences, Brunel University London, Uxbridge UB8 3PH, UK; (I.M.J.)
| | - Alessandra Mazzola
- Division of Biosciences, Brunel University London, Uxbridge UB8 3PH, UK; (I.M.J.)
- Department of Biopathology and Medical and Forensic Biotechnologies, University of Palermo, 90133 Palermo, Italy
| | - Thomas Höfken
- Division of Biosciences, Brunel University London, Uxbridge UB8 3PH, UK; (I.M.J.)
- Institute of Biochemistry, Kiel University, 24118 Kiel, Germany
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3
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Thongchot S, Aksonnam K, Thuwajit P, Yenchitsomanus PT, Thuwajit C. Nucleolin‑based targeting strategies in cancer treatment: Focus on cancer immunotherapy (Review). Int J Mol Med 2023; 52:81. [PMID: 37477132 PMCID: PMC10555485 DOI: 10.3892/ijmm.2023.5284] [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: 03/27/2023] [Accepted: 06/15/2023] [Indexed: 07/22/2023] Open
Abstract
The benefits of treating several types of cancers using immunotherapy have recently been established. The overexpression of nucleolin (NCL) in a number of types of cancer provides an attractive antigen target for the development of novel anticancer immunotherapeutic treatments. NCL is a multifunctional protein abundantly distributed in the nucleus, cytoplasm and cell membrane. It influences carcinogenesis, and the proliferation, survival and metastasis of cancer cells, leading to cancer progression. Additionally, the meta‑analysis of total and cytoplasmic NCL overexpression indicates a poor prognosis of patients with breast cancer. The AS1411 aptamers currently appear to have therapeutic action in the phase II clinical trial. The authors' research group has recently explored the anticancer function of NCL through the activation of T cells by dendritic cell‑based immunotherapy. The present review describes and discusses the mechanisms through which the multiple functions of NCL can participate in the progression of cancer. In addition, the studies that define the utility of NCL‑dependent anticancer therapies are summarized, with specific focus being paid to cancer immunotherapeutic approaches.
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Affiliation(s)
- Suyanee Thongchot
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University
- Siriraj Center of Research Excellence for Cancer Immunotherapy (SiCORE-CIT), Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University
| | - Krittaya Aksonnam
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University
| | - Peti Thuwajit
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University
| | - Pa-Thai Yenchitsomanus
- Siriraj Center of Research Excellence for Cancer Immunotherapy (SiCORE-CIT), Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University
- Division of Molecular Medicine, Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Chanitra Thuwajit
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University
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Remines M, Schoonover M, Knox Z, Kenwright K, Hoffert KM, Coric A, Mead J, Ampfer J, Seye S, Strome ED. Profiling The Compendium Of Changes In Saccharomyces cerevisiae Due To Mutations That Alter Availability Of The Main Methyl Donor S-Adenosylmethionine. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.09.544294. [PMID: 37333147 PMCID: PMC10274911 DOI: 10.1101/2023.06.09.544294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
The SAM1 and SAM2 genes encode for S-AdenosylMethionine (AdoMet) synthetase enzymes, with AdoMet serving as the main methyl donor. We have previously shown that independent deletion of these genes alters chromosome stability and AdoMet concentrations in opposite ways in S. cerevisiae. To characterize other changes occurring in these mutants, we grew wildtype, sam1∆/sam1∆, and sam2∆/sam2∆ strains in 15 different Phenotypic Microarray plates with different components, equal to 1440 wells, and measured for growth variations. RNA-Sequencing was also carried out on these strains and differential gene expression determined for each mutant. In this study, we explore how the phenotypic growth differences are linked to the altered gene expression, and thereby predict the mechanisms by which loss of the SAM genes and subsequent AdoMet level changes, impact S. cerevisiae pathways and processes. We present six stories, discussing changes in sensitivity or resistance to azoles, cisplatin, oxidative stress, arginine biosynthesis perturbations, DNA synthesis inhibitors, and tamoxifen, to demonstrate the power of this novel methodology to broadly profile changes due to gene mutations. The large number of conditions that result in altered growth, as well as the large number of differentially expressed genes with wide-ranging functionality, speaks to the broad array of impacts that altering methyl donor abundance can impart, even when the conditions tested were not specifically selected as targeting known methyl involving pathways. Our findings demonstrate that some cellular changes are directly related to AdoMet-dependent methyltransferases and AdoMet availability, some are directly linked to the methyl cycle and its role is production of several important cellular components, and others reveal impacts of SAM gene mutations on previously unconnected pathways.
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Affiliation(s)
- McKayla Remines
- Department of Biological Sciences, Northern Kentucky University, Highland Heights, KY 41099
| | - Makailyn Schoonover
- Department of Biological Sciences, Northern Kentucky University, Highland Heights, KY 41099
| | - Zoey Knox
- Department of Biological Sciences, Northern Kentucky University, Highland Heights, KY 41099
| | - Kailee Kenwright
- Department of Biological Sciences, Northern Kentucky University, Highland Heights, KY 41099
| | - Kellyn M. Hoffert
- Department of Biological Sciences, Northern Kentucky University, Highland Heights, KY 41099
| | - Amila Coric
- Department of Biological Sciences, Northern Kentucky University, Highland Heights, KY 41099
| | - James Mead
- Department of Biological Sciences, Northern Kentucky University, Highland Heights, KY 41099
| | - Joseph Ampfer
- Department of Biological Sciences, Northern Kentucky University, Highland Heights, KY 41099
| | - Serigne Seye
- Department of Biological Sciences, Northern Kentucky University, Highland Heights, KY 41099
| | - Erin D. Strome
- Department of Biological Sciences, Northern Kentucky University, Highland Heights, KY 41099
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5
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Role of Heterogeneous Nuclear Ribonucleoproteins in the Cancer-Immune Landscape. Int J Mol Sci 2023; 24:ijms24065086. [PMID: 36982162 PMCID: PMC10049280 DOI: 10.3390/ijms24065086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 02/26/2023] [Accepted: 02/28/2023] [Indexed: 03/09/2023] Open
Abstract
Cancer remains the second leading cause of death, accounting for approximately 20% of all fatalities. Evolving cancer cells and a dysregulated immune system create complex tumor environments that fuel tumor growth, metastasis, and resistance. Over the past decades, significant progress in deciphering cancer cell behavior and recognizing the immune system as a hallmark of tumorigenesis has been achieved. However, the underlying mechanisms controlling the evolving cancer-immune landscape remain mostly unexplored. Heterogeneous nuclear ribonuclear proteins (hnRNP), a highly conserved family of RNA-binding proteins, have vital roles in critical cellular processes, including transcription, post-transcriptional modifications, and translation. Dysregulation of hnRNP is a critical contributor to cancer development and resistance. HnRNP contribute to the diversity of tumor and immune-associated aberrant proteomes by controlling alternative splicing and translation. They can also promote cancer-associated gene expression by regulating transcription factors, binding to DNA directly, or promoting chromatin remodeling. HnRNP are emerging as newly recognized mRNA readers. Here, we review the roles of hnRNP as regulators of the cancer-immune landscape. Dissecting the molecular functions of hnRNP will provide a better understanding of cancer-immune biology and will impact the development of new approaches to control and treat cancer.
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6
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Ling Q, Liao J, Liu X, Zhou Y, Qian Y. Genome-Wide Identification of Maize Protein Arginine Methyltransferase Genes and Functional Analysis of ZmPRMT1 Reveal Essential Roles in Arabidopsis Flowering Regulation and Abiotic Stress Tolerance. Int J Mol Sci 2022; 23:12793. [PMID: 36361583 PMCID: PMC9655960 DOI: 10.3390/ijms232112793] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/17/2022] [Accepted: 10/20/2022] [Indexed: 10/29/2023] Open
Abstract
Histone methylation, as one of the important epigenetic regulatory mechanisms, plays a significant role in growth and developmental processes and stress responses of plants, via altering the methylation status or ratio of arginine and lysine residues of histone tails, which can affect the regulation of gene expression. Protein arginine methyltransferases (PRMTs) have been revealed to be responsible for histone methylation of specific arginine residues in plants, which is important for maintaining pleiotropic development and adaptation to abiotic stresses in plants. Here, for the first time, a total of eight PRMT genes in maize have been identified and characterized in this study, named as ZmPRMT1-8. According to comparative analyses of phylogenetic relationship and structural characteristics among PRMT gene family members from several representative species, all maize 8 PRMT proteins were categorized into three distinct subfamilies. Further, schematic structure and chromosome location analyses displayed evolutionarily conserved structure features and an unevenly distribution on maize chromosomes of ZmPRMT genes, respectively. The expression patterns of ZmPRMT genes in different tissues and under various abiotic stresses (heat, drought, and salt) were determined. The expression patterns of ZmPRMT genes indicated that they play a role in regulating growth and development and responses to abiotic stress. Eventually, to verify the biological roles of ZmPRMT genes, the transgenic Arabidopsis plants overexpressing ZmPRMT1 gene was constructed as a typical representative. The results demonstrated that overexpression of ZmPRMT1 can promote earlier flowering time and confer enhanced heat tolerance in transgenic Arabidopsis. Taken together, our results are the first to report the roles of ZmPRMT1 gene in regulating flowering time and resisting heat stress response in plants and will provide a vital theoretical basis for further unraveling the functional roles and epigenetic regulatory mechanism of ZmPRMT genes in maize growth, development and responses to abiotic stresses.
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Affiliation(s)
| | | | | | | | - Yexiong Qian
- Anhui Provincial Key Laboratory of Conservation and Exploitation of Important Biological Resources, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
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7
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England WE, Wang J, Chen S, Baldi P, Flynn RA, Spitale RC. An atlas of posttranslational modifications on RNA binding proteins. Nucleic Acids Res 2022; 50:4329-4339. [PMID: 35438783 PMCID: PMC9071496 DOI: 10.1093/nar/gkac243] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 03/24/2022] [Accepted: 04/15/2022] [Indexed: 12/13/2022] Open
Abstract
RNA structure and function are intimately tied to RNA binding protein recognition and regulation. Posttranslational modifications are chemical modifications which can control protein biology. The role of PTMs in the regulation RBPs is not well understood, in part due to a lacking analysis of PTM deposition on RBPs. Herein, we present an analysis of posttranslational modifications (PTMs) on RNA binding proteins (RBPs; a PTM RBP Atlas). We curate published datasets and primary literature to understand the landscape of PTMs and use protein-protein interaction data to understand and potentially provide a framework for understanding which enzymes are controlling PTM deposition and removal on the RBP landscape. Intersection of our data with The Cancer Genome Atlas also provides researchers understanding of mutations that would alter PTM deposition. Additional characterization of the RNA-protein interface provided from in-cell UV crosslinking experiments provides a framework for hypotheses about which PTMs could be regulating RNA binding and thus RBP function. Finally, we provide an online database for our data that is easy to use for the community. It is our hope our efforts will provide researchers will an invaluable tool to test the function of PTMs controlling RBP function and thus RNA biology.
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Affiliation(s)
- Whitney E England
- Department of Pharmaceutical Sciences, University of California, Irvine. Irvine, CA, USA
| | - Jingtian Wang
- Department of Pharmaceutical Sciences, University of California, Irvine. Irvine, CA, USA
| | - Siwei Chen
- School of Information and Computer Sciences, University of California, Irvine. Irvine, CA, USA
| | - Pierre Baldi
- School of Information and Computer Sciences, University of California, Irvine. Irvine, CA, USA
| | - Ryan A Flynn
- Stem Cell Program, Boston Children's Hospital, Boston, MA, USA.,Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA
| | - Robert C Spitale
- Department of Pharmaceutical Sciences, University of California, Irvine. Irvine, CA, USA.,Department of Developmental and Cellular Biology, University of California, Irvine. Irvine, CA, USA.,Department of Chemistry, University of California, Irvine. Irvine, CA, USA
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8
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PRMT5: An Emerging Target for Pancreatic Adenocarcinoma. Cancers (Basel) 2021; 13:cancers13205136. [PMID: 34680285 PMCID: PMC8534199 DOI: 10.3390/cancers13205136] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/11/2021] [Accepted: 10/12/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary The burden of pancreatic ductal adenocarcinoma (PDAC) increases with rising incidence, yet 5-year overall survival remains poor at 17%. Routine comprehensive genomic profiling of PDAC only finds 2.5% of patients who may benefit and receive matched targeted therapy. Protein arginine methyltransferase 5 (PRMT5) as an anti-cancer target has gained significant interest in recent years and high levels of PRMT5 protein are associated with worse survival outcomes across multiple cancer types. Inhibition of PRMT5 in pre-clinical models can lead to cancer growth inhibition. However, PRMT5 is involved in multiple cellular processes, thus determining its mechanism of action is challenging. While past reviews on PRMT5 have focused on its role in diverse cellular processes and past research studies have focused mainly on haematological malignancies and glioblastoma, this review provides an overview of the possible biological mechanisms of action of PRMT5 inhibition and its potential as a treatment in pancreatic cancer. Abstract The overall survival of pancreatic ductal adenocarcinoma (PDAC) remains poor and its incidence is rising. Targetable mutations in PDAC are rare, thus novel therapeutic approaches are needed. Protein arginine methyltransferase 5 (PRMT5) overexpression is associated with worse survival and inhibition of PRMT5 results in decreased cancer growth across multiple cancers, including PDAC. Emerging evidence also suggests that altered RNA processing is a driver in PDAC tumorigenesis and creates a partial dependency on this process. PRMT5 inhibition induces altered splicing and this vulnerability can be exploited as a novel therapeutic approach. Three possible biological pathways underpinning the action of PRMT5 inhibitors are discussed; c-Myc regulation appears central to its action in the PDAC setting. Whilst homozygous MTAP deletion and symmetrical dimethylation levels are associated with increased sensitivity to PRMT5 inhibition, neither measure robustly predicts its growth inhibitory response. The immunomodulatory effect of PRMT5 inhibitors on the tumour microenvironment will also be discussed, based on emerging evidence that PDAC stroma has a significant bearing on disease behaviour and response to therapy. Lastly, with the above caveats in mind, current knowledge gaps and the implications and rationales for PRMT5 inhibitor development in PDAC will be explored.
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9
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Parbin S, Damodharan S, Rajyaguru PI. Arginine methylation and cytoplasmic mRNA fate: An exciting new partnership. Yeast 2021; 38:441-452. [PMID: 34048611 DOI: 10.1002/yea.3653] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 05/12/2021] [Accepted: 05/20/2021] [Indexed: 12/22/2022] Open
Abstract
Posttranslational modifications play a crucial role in regulating gene expression. Among these modifications, arginine methylation has recently attracted tremendous attention due to its role in multiple cellular functions. This review discusses the recent advances that have established arginine methylation as a major player in determining cytoplasmic messenger RNA (mRNA) fate. We specifically focus on research that implicates arginine methylation in regulating mRNA translation, decay, and RNA granule dynamics. Based on this research, we highlight a few emerging future avenues that will lead to exciting discoveries in this field.
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Affiliation(s)
- Sabnam Parbin
- Department of Biochemistry, Indian Institute of Science, Bangalore, India.,Integrative Genomics Core Unit, University Medical Centre, Göttingen, Göttingen, Germany
| | - Subha Damodharan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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10
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Hamey JJ, Nguyen A, Wilkins MR. Discovery of Arginine Methylation, Phosphorylation, and Their Co-occurrence in Condensate-Associated Proteins in Saccharomyces cerevisiae. J Proteome Res 2021; 20:2420-2434. [PMID: 33856219 DOI: 10.1021/acs.jproteome.0c00927] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The formation of condensates in membraneless organelles is thought to be driven by protein phase separation. Arginine methylation and serine/threonine phosphorylation are important in the phase separation process; however, these post-translational modifications are often present in intrinsically disordered regions that are difficult to analyze with standard proteomic techniques. To understand their presence and co-occurrence in condensate-associated proteins, here, we use a multiprotease and multi-tandem mass spectrometry (MS/MS) fragmentation approach, coupled with heavy methyl stable isotope labeling of amino acids in cell culture (SILAC) and phospho- or methyl-peptide enrichment. For Saccharomyces cerevisiae, we report a 50% increase in the known arginine methylproteome, involving 15 proteins that are all condensate-associated. Importantly, some of these proteins have arginine methylation on all predicted sites-providing evidence that this modification can be pervasive. We explored whether arginine-methylated, condensate-associated proteins are also phosphorylated and found 12 such proteins to carry phosphorylated serine or threonine. In Npl3, Ded1, and Sbp1, single peptides were found to carry both modifications, indicating a co-occurrence in close proximity and on the same protein molecule. These co-modifications occur in regions of disorder, whereas arginine methylation is typically on regions of disorder that are also basic. For phosphorylation, its association with charged regions of condensate-associated proteins was less consistent, although some regions with multisite phosphorylation sites were strongly acidic. We conclude that arginine-methylated proteins associated with condensates are typically also modified with protein phosphorylation.
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Affiliation(s)
- Joshua J Hamey
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Amy Nguyen
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Marc R Wilkins
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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11
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Sandhu R, Sinha A, Montpetit B. The SR-protein Npl3 is an essential component of the meiotic splicing regulatory network in Saccharomyces cerevisiae. Nucleic Acids Res 2021; 49:2552-2568. [PMID: 33577675 PMCID: PMC7969001 DOI: 10.1093/nar/gkab071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/25/2021] [Accepted: 01/27/2021] [Indexed: 01/30/2023] Open
Abstract
The meiotic gene expression program in Saccharomyces cerevisiae involves regulated splicing of meiosis-specific genes via multiple splicing activators (e.g. Mer1, Nam8, Tgs1). Here, we show that the SR protein Npl3 is required for meiotic splicing regulation and is essential for proper execution of the meiotic cell cycle. The loss of Npl3, though not required for viability in mitosis, caused intron retention in meiosis-specific transcripts, inefficient meiotic double strand break processing and an arrest of the meiotic cell cycle. The targets of Npl3 overlapped in some cases with other splicing regulators, while also having unique target transcripts that were not shared. In the absence of Npl3, splicing defects for three transcripts (MER2, HOP2 and SAE3) were rescued by conversion of non-consensus splice sites to the consensus sequence. Methylation of Npl3 was further found to be required for splicing Mer1-dependent transcripts, indicating transcript-specific mechanisms by which Npl3 supports splicing. Together these data identify an essential function for the budding yeast SR protein Npl3 in meiosis as part of the meiotic splicing regulatory network.
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Affiliation(s)
- Rima Sandhu
- Department of Viticulture and Enology, University of California Davis, Davis, CA, USA
| | - Aniketa Sinha
- Department of Viticulture and Enology, University of California Davis, Davis, CA, USA
| | - Ben Montpetit
- Department of Viticulture and Enology, University of California Davis, Davis, CA, USA
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12
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The Regulatory Properties of the Ccr4-Not Complex. Cells 2020; 9:cells9112379. [PMID: 33138308 PMCID: PMC7692201 DOI: 10.3390/cells9112379] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/21/2020] [Accepted: 10/26/2020] [Indexed: 12/12/2022] Open
Abstract
The mammalian Ccr4–Not complex, carbon catabolite repression 4 (Ccr4)-negative on TATA-less (Not), is a large, highly conserved, multifunctional assembly of proteins that acts at different cellular levels to regulate gene expression. In the nucleus, it is involved in the regulation of the cell cycle, chromatin modification, activation and inhibition of transcription initiation, control of transcription elongation, RNA export, nuclear RNA surveillance, and DNA damage repair. In the cytoplasm, the Ccr4–Not complex plays a central role in mRNA decay and affects protein quality control. Most of our original knowledge of the Ccr4–Not complex is derived, primarily, from studies in yeast. More recent studies have shown that the mammalian complex has a comparable structure and similar properties. In this review, we summarize the evidence for the multiple roles of both the yeast and mammalian Ccr4–Not complexes, highlighting their similarities.
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13
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Szulik MW, Davis K, Bakhtina A, Azarcon P, Bia R, Horiuchi E, Franklin S. Transcriptional regulation by methyltransferases and their role in the heart: highlighting novel emerging functionality. Am J Physiol Heart Circ Physiol 2020; 319:H847-H865. [PMID: 32822544 DOI: 10.1152/ajpheart.00382.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Methyltransferases are a superfamily of enzymes that transfer methyl groups to proteins, nucleic acids, and small molecules. Traditionally, these enzymes have been shown to carry out a specific modification (mono-, di-, or trimethylation) on a single, or limited number of, amino acid(s). The largest subgroup of this family, protein methyltransferases, target arginine and lysine side chains of histone molecules to regulate gene expression. Although there is a large number of functional studies that have been performed on individual methyltransferases describing their methylation targets and effects on biological processes, no analyses exist describing the spatial distribution across tissues or their differential expression in the diseased heart. For this review, we performed tissue profiling in protein databases of 199 confirmed or putative methyltransferases to demonstrate the unique tissue-specific expression of these individual proteins. In addition, we examined transcript data sets from human heart failure patients and murine models of heart disease to identify 40 methyltransferases in humans and 15 in mice, which are differentially regulated in the heart, although many have never been functionally interrogated. Lastly, we focused our analysis on the largest subgroup, that of protein methyltransferases, and present a newly emerging phenomenon in which 16 of these enzymes have been shown to play dual roles in regulating transcription by maintaining the ability to both activate and repress transcription through methyltransferase-dependent or -independent mechanisms. Overall, this review highlights a novel paradigm shift in our understanding of the function of histone methyltransferases and correlates their expression in heart disease.
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Affiliation(s)
- Marta W Szulik
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
| | - Kathryn Davis
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
| | - Anna Bakhtina
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
| | - Presley Azarcon
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
| | - Ryan Bia
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
| | - Emilee Horiuchi
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
| | - Sarah Franklin
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah.,Division of Cardiovascular Medicine, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, Utah
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14
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Kaur R, Lal SK. The multifarious roles of heterogeneous ribonucleoprotein A1 in viral infections. Rev Med Virol 2020; 30:e2097. [PMID: 31989716 PMCID: PMC7169068 DOI: 10.1002/rmv.2097] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 12/19/2019] [Accepted: 12/30/2019] [Indexed: 12/13/2022]
Abstract
Viruses are obligate parasites known to interact with a wide variety of host proteins at different stages of infection. Current antiviral treatments target viral proteins and may be compromised due to the emergence of drug resistant viral strains. Targeting viral-host interactions is now gaining recognition as an alternative approach against viral infections. Recent research has revealed that heterogeneous ribonucleoprotein A1, an RNA-binding protein, plays an essential functional and regulatory role in the life cycle of many viruses. In this review, we summarize the interactions between heterogeneous ribonucleoprotein A1 (hnRNPA1) and multiple viral proteins during the life cycle of RNA and DNA viruses. hnRNPA1 protein levels are modulated differently, in different viruses, which further dictates its stability, function, and intracellular localization. Multiple reports have emphasized that in Sindbis virus, enteroviruses, porcine endemic diarrhea virus, and rhinovirus infection, hnRNPA1 enhances viral replication and survival. However, in others like hepatitis C virus and human T-cell lymphotropic virus, it exerts a protective response. The involvement of hnRNPA1 in viral infections highlights its importance as a central regulator of host and viral gene expression. Understanding the nature of these interactions will increase our understanding of specific viral infections and pathogenesis and eventually aid in the development of novel and robust antiviral intervention strategies.
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Affiliation(s)
- Ramandeep Kaur
- Tropical Medicine and Biology Platform & School of Science, Monash University, 47500 Bandar Sunway, Selangor DE, Malaysia
| | - Sunil K Lal
- Tropical Medicine and Biology Platform & School of Science, Monash University, 47500 Bandar Sunway, Selangor DE, Malaysia
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15
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Crosstalk of Phosphorylation and Arginine Methylation in Disordered SRGG Repeats of Saccharomyces cerevisiae Fibrillarin and Its Association with Nucleolar Localization. J Mol Biol 2020; 432:448-466. [DOI: 10.1016/j.jmb.2019.11.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 10/18/2019] [Accepted: 11/05/2019] [Indexed: 11/19/2022]
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16
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Protein Arginine Methyltransferases in Cardiovascular and Neuronal Function. Mol Neurobiol 2019; 57:1716-1732. [PMID: 31823198 DOI: 10.1007/s12035-019-01850-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 12/01/2019] [Indexed: 12/16/2022]
Abstract
The methylation of arginine residues by protein arginine methyltransferases (PRMTs) is a type of post-translational modification which is important for numerous cellular processes, including mRNA splicing, DNA repair, signal transduction, protein interaction, and transport. PRMTs have been extensively associated with various pathologies, including cancer, inflammation, and immunity response. However, the role of PRMTs has not been well described in vascular and neurological function. Aberrant expression of PRMTs can alter its metabolic products, asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA). Increased ADMA levels are recognized as an independent risk factor for cardiovascular disease and mortality. Recent studies have provided considerable advances in the development of small-molecule inhibitors of PRMTs to study their function under normal and pathological states. In this review, we aim to elucidate the particular roles of PRMTs in vascular and neuronal function as a potential target for cardiovascular and neurological diseases.
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17
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Hartel NG, Chew B, Qin J, Xu J, Graham NA. Deep Protein Methylation Profiling by Combined Chemical and Immunoaffinity Approaches Reveals Novel PRMT1 Targets. Mol Cell Proteomics 2019; 18:2149-2164. [PMID: 31451547 PMCID: PMC6823857 DOI: 10.1074/mcp.ra119.001625] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Indexed: 01/02/2023] Open
Abstract
Protein methylation has been implicated in many important biological contexts including signaling, metabolism, and transcriptional control. Despite the importance of this post-translational modification, the global analysis of protein methylation by mass spectrometry-based proteomics has not been extensively studied because of the lack of robust, well-characterized techniques for methyl peptide enrichment. Here, to better investigate protein methylation, we compared two methods for methyl peptide enrichment: immunoaffinity purification (IAP) and high pH strong cation exchange (SCX). Using both methods, we identified 1720 methylation sites on 778 proteins. Comparison of these methods revealed that they are largely orthogonal, suggesting that the usage of both techniques is required to provide a global view of protein methylation. Using both IAP and SCX, we then investigated changes in protein methylation downstream of protein arginine methyltransferase 1 (PRMT1). PRMT1 knockdown resulted in significant changes to 127 arginine methylation sites on 78 proteins. In contrast, only a single lysine methylation site was significantly changed upon PRMT1 knockdown. In PRMT1 knockdown cells, we found 114 MMA sites that were either significantly downregulated or upregulated on proteins enriched for mRNA metabolic processes. PRMT1 knockdown also induced significant changes in both asymmetric dimethyl arginine (ADMA) and symmetric dimethyl arginine (SDMA). Using characteristic neutral loss fragmentation ions, we annotated dimethylarginines as either ADMA or SDMA. Through integrative analysis of methyl forms, we identified 18 high confidence PRMT1 substrates and 12 methylation sites that are scavenged by other non-PRMT1 arginine methyltransferases in the absence of PRMT1 activity. We also identified one methylation site, HNRNPA1 R206, which switched from ADMA to SDMA upon PRMT1 knockdown. Taken together, our results suggest that deep protein methylation profiling by mass spectrometry requires orthogonal enrichment techniques to identify novel PRMT1 methylation targets and highlight the dynamic interplay between methyltransferases in mammalian cells.
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Affiliation(s)
- Nicolas G Hartel
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089
| | - Brandon Chew
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089
| | - Jian Qin
- Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California 90089; Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, California 90089; Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California 90089
| | - Jian Xu
- Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California 90089; Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, California 90089; Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California 90089
| | - Nicholas A Graham
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089; Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California 90089.
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18
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You ST, Jhou YT, Kao CF, Leu JY. Experimental evolution reveals a general role for the methyltransferase Hmt1 in noise buffering. PLoS Biol 2019; 17:e3000433. [PMID: 31613873 PMCID: PMC6814240 DOI: 10.1371/journal.pbio.3000433] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 10/25/2019] [Accepted: 09/27/2019] [Indexed: 11/19/2022] Open
Abstract
Cell-to-cell heterogeneity within an isogenic population has been observed in prokaryotic and eukaryotic cells. Such heterogeneity often manifests at the level of individual protein abundance and may have evolutionary benefits, especially for organisms in fluctuating environments. Although general features and the origins of cellular noise have been revealed, details of the molecular pathways underlying noise regulation remain elusive. Here, we used experimental evolution of Saccharomyces cerevisiae to select for mutations that increase reporter protein noise. By combining bulk segregant analysis and CRISPR/Cas9-based reconstitution, we identified the methyltransferase Hmt1 as a general regulator of noise buffering. Hmt1 methylation activity is critical for the evolved phenotype, and we also show that two of the Hmt1 methylation targets can suppress noise. Hmt1 functions as an environmental sensor to adjust noise levels in response to environmental cues. Moreover, Hmt1-mediated noise buffering is conserved in an evolutionarily distant yeast species, suggesting broad significance of noise regulation. Experimental evolution in yeast reveals that the methyltransferase Hmt1 functions as a mediator connecting environmental stimuli to cellular noise; Hmt1-mediated noise buffering is conserved in an evolutionarily distant yeast.
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Affiliation(s)
- Shu-Ting You
- Molecular and Cell Biology, Taiwan International Graduate Program, Graduate Institute of Life Sciences, National Defense Medical Center and Academia Sinica, Taipei, Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Yu-Ting Jhou
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Cheng-Fu Kao
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Jun-Yi Leu
- Molecular and Cell Biology, Taiwan International Graduate Program, Graduate Institute of Life Sciences, National Defense Medical Center and Academia Sinica, Taipei, Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- * E-mail:
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19
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Duijkers FA, McDonald A, Janssens GE, Lezzerini M, Jongejan A, van Koningsbruggen S, Leeuwenburgh-Pronk WG, Wlodarski MW, Moutton S, Tran-Mau-Them F, Thauvin-Robinet C, Faivre L, Monaghan KG, Smol T, Boute-Benejean O, Ladda RL, Sell SL, Bruel AL, Houtkooper RH, MacInnes AW. HNRNPR Variants that Impair Homeobox Gene Expression Drive Developmental Disorders in Humans. Am J Hum Genet 2019; 104:1040-1059. [PMID: 31079900 PMCID: PMC6556882 DOI: 10.1016/j.ajhg.2019.03.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 03/25/2019] [Indexed: 12/18/2022] Open
Abstract
The heterogeneous nuclear ribonucleoprotein (HNRNP) genes code for a set of RNA-binding proteins that function primarily in the spliceosome C complex. Pathogenic variants in these genes can drive neurodegeneration, through a mechanism involving excessive stress-granule formation, or developmental defects, through mechanisms that are not known. Here, we report four unrelated individuals who have truncating or missense variants in the same C-terminal region of hnRNPR and who have multisystem developmental defects including abnormalities of the brain and skeleton, dysmorphic facies, brachydactyly, seizures, and hypoplastic external genitalia. We further identified in the literature a fifth individual with a truncating variant. RNA sequencing of primary fibroblasts reveals that these HNRNPR variants drive significant changes in the expression of several homeobox genes, as well as other transcription factors, such as LHX9, TBX1, and multiple HOX genes, that are considered fundamental regulators of embryonic and gonad development. Higher levels of retained intronic HOX sequences and lost splicing events in the HOX cluster are observed in cells carrying HNRNPR variants, suggesting that impaired splicing is at least partially driving HOX deregulation. At basal levels, stress-granule formation appears normal in primary and transfected cells expressing HNRNPR variants. However, these cells reveal profound recovery defects, where stress granules fail to disassemble properly, after exposure to oxidative stress. This study establishes an essential role for HNRNPR in human development and points to a mechanism that may unify other "spliceosomopathies" linked to variants that drive multi-system congenital defects and are found in hnRNPs.
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Affiliation(s)
- Floor A Duijkers
- Amsterdam University Medical Centers, University of Amsterdam, Department of Clinical Genetics, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - Andrew McDonald
- Amsterdam University Medical Centers, University of Amsterdam, Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology and Metabolism, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - Georges E Janssens
- Amsterdam University Medical Centers, University of Amsterdam, Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology and Metabolism, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - Marco Lezzerini
- Amsterdam University Medical Centers, University of Amsterdam, Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology and Metabolism, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - Aldo Jongejan
- Amsterdam University Medical Centers, University of Amsterdam, Bioinformatics Laboratory, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - Silvana van Koningsbruggen
- Amsterdam University Medical Centers, University of Amsterdam, Department of Clinical Genetics, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - Wendela G Leeuwenburgh-Pronk
- Amsterdam University Medical Centers, University of Amsterdam, Department of Pediatrics, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - Marcin W Wlodarski
- Department of Pediatric Hematology and Oncology, University of Freiburg, D-79106 Freiburg, Germany
| | - Sébastien Moutton
- Institut National de la Santé et de la Recherche Médicale UMR 1231 GAD, Génétique des Anomalies du Dévelopement, Université de Bourgogne-Franche Comté, F-21079 Dijon, France; Fédération Hospitalo-Universitaire Médecine TRANSLationnelle et Anomalies du Développement, Centre Hospitalier Universitaire et Université de Bourgogne-Franche Comté, 21000 Dijon, France; Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'Inter-région Est, Centre Hospitalier Universitaire Dijon Bourgogne, F-21079 Dijon, France
| | - Frédéric Tran-Mau-Them
- Institut National de la Santé et de la Recherche Médicale UMR 1231 GAD, Génétique des Anomalies du Dévelopement, Université de Bourgogne-Franche Comté, F-21079 Dijon, France; Fédération Hospitalo-Universitaire Médecine TRANSLationnelle et Anomalies du Développement, Centre Hospitalier Universitaire et Université de Bourgogne-Franche Comté, 21000 Dijon, France
| | - Christel Thauvin-Robinet
- Institut National de la Santé et de la Recherche Médicale UMR 1231 GAD, Génétique des Anomalies du Dévelopement, Université de Bourgogne-Franche Comté, F-21079 Dijon, France; Fédération Hospitalo-Universitaire Médecine TRANSLationnelle et Anomalies du Développement, Centre Hospitalier Universitaire et Université de Bourgogne-Franche Comté, 21000 Dijon, France; Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'Inter-région Est, Centre Hospitalier Universitaire Dijon Bourgogne, F-21079 Dijon, France
| | - Laurence Faivre
- Institut National de la Santé et de la Recherche Médicale UMR 1231 GAD, Génétique des Anomalies du Dévelopement, Université de Bourgogne-Franche Comté, F-21079 Dijon, France
| | | | - Thomas Smol
- Université de Lille, EA 7364 - RADEME, F-59000 Lille, France; Centre Hospitalier Universitaire Lille, Institut de Génétique Médicale, F-59000 Lille, France
| | - Odile Boute-Benejean
- Université de Lille, EA 7364 - RADEME, F-59000 Lille, France; Centre Hospitalier Universitaire Lille, Institut de Génétique Médicale, F-59000 Lille, France
| | - Roger L Ladda
- Department of Pediatrics, Penn State Children's Hospital, Hershey, PA 17033, USA
| | - Susan L Sell
- Department of Pediatrics, Penn State Children's Hospital, Hershey, PA 17033, USA
| | - Ange-Line Bruel
- Institut National de la Santé et de la Recherche Médicale UMR 1231 GAD, Génétique des Anomalies du Dévelopement, Université de Bourgogne-Franche Comté, F-21079 Dijon, France; Fédération Hospitalo-Universitaire Médecine TRANSLationnelle et Anomalies du Développement, Centre Hospitalier Universitaire et Université de Bourgogne-Franche Comté, 21000 Dijon, France
| | - Riekelt H Houtkooper
- Amsterdam University Medical Centers, University of Amsterdam, Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology and Metabolism, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - Alyson W MacInnes
- Amsterdam University Medical Centers, University of Amsterdam, Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology and Metabolism, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands.
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20
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Bauer I, Lechner L, Pidroni A, Petrone AM, Merschak P, Lindner H, Kremser L, Graessle S, Golderer G, Allipour S, Brosch G. Type I and II PRMTs regulate catabolic as well as detoxifying processes in Aspergillus nidulans. Fungal Genet Biol 2019; 129:86-100. [PMID: 31145992 DOI: 10.1016/j.fgb.2019.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 05/03/2019] [Accepted: 05/24/2019] [Indexed: 11/28/2022]
Abstract
In filamentous fungi, arginine methylation has been implicated in morphogenesis, mycotoxin biosynthesis, pathogenicity, and stress response although the exact role of this posttranslational modification in these processes remains obscure. Here, we present the first genome-wide transcriptome analysis in filamentous fungi that compared expression levels of genes regulated by type I and type II protein arginine methyltransferases (PRMTs). In Aspergillus nidulans, three conserved type I and II PRMTs are present that catalyze asymmetric or symmetric dimethylation of arginines. We generated a double type I mutant (ΔrmtA/rmtB) and a combined type I and type II mutant (ΔrmtB/rmtC) to perform genome-wide comparison of their effects on gene expression, but also to monitor putative overlapping activities and reciprocal regulations of type I and type II PRMTs in Aspergillus. Our study demonstrates, that rmtA and rmtC as type I and type II representatives act together as repressors of proteins that are secreted into the extracellular region as the majority of up-regulated genes are mainly involved in catabolic pathways that constitute the secretome of Aspergillus. In addition to a strong up-regulation of secretory genes we found a significant enrichment of down-regulated genes involved in processes related to oxidation-reduction, transmembrane transport and secondary metabolite biosynthesis. Strikingly, nearly 50% of down-regulated genes in both double mutants correspond to redox reaction/oxidoreductase processes, a remarkable finding in light of our recently observed oxidative stress phenotypes of ΔrmtA and ΔrmtC. Finally, analysis of nuclear and cytoplasmic extracts for mono-methylated proteins revealed the presence of both, common and specific substrates of RmtA and RmtC. Thus, our data indicate that type I and II PRMTs in Aspergillus seem to co-regulate the same biological processes but also specifically affect other pathways in a non-redundant fashion.
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Affiliation(s)
- Ingo Bauer
- Division of Molecular Biology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Lukas Lechner
- Division of Molecular Biology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Angelo Pidroni
- Division of Molecular Biology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Anna-Maria Petrone
- Division of Molecular Biology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Petra Merschak
- Division of Molecular Biology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Herbert Lindner
- Division of Clinical Biochemistry, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Leopold Kremser
- Division of Clinical Biochemistry, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Stefan Graessle
- Division of Molecular Biology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Georg Golderer
- Division of Biological Chemistry, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Shadab Allipour
- Division of Molecular Biology, Medical University of Innsbruck, 6020 Innsbruck, Austria.
| | - Gerald Brosch
- Division of Molecular Biology, Medical University of Innsbruck, 6020 Innsbruck, Austria.
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21
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Zhang J, Jing L, Li M, He L, Guo Z. Regulation of histone arginine methylation/demethylation by methylase and demethylase (Review). Mol Med Rep 2019; 19:3963-3971. [PMID: 30942418 PMCID: PMC6471501 DOI: 10.3892/mmr.2019.10111] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 03/06/2019] [Indexed: 12/13/2022] Open
Abstract
Histone arginine methylation is a universal post-translational modification that has been implicated in multiple cellular and sub-cellular processes, including pre-mRNA splicing, DNA damage signaling, mRNA translation, cell signaling and cell death. Despite these important roles, the understanding of its regulation with respect to certain other modifications, such as phosphorylation and acetylation, is very poor. Thus far, few histone arginine demethylases have been identified in mammalian cells, compared with nine protein arginine methyltransferases (PRMTs) that have been reported. Studies have reported that aberrant histone arginine methylation is strongly associated with carcinogenesis and metastasis. This increases the requirement for understanding the regulation of histone arginine demethylation. The present review summarizes the published studies and provides further insights into histone arginine methylases and demethylases.
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Affiliation(s)
- Jing Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210097, P.R. China
| | - Li Jing
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210097, P.R. China
| | - Menghan Li
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210097, P.R. China
| | - Lingfeng He
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210097, P.R. China
| | - Zhigang Guo
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210097, P.R. China
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22
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Chia SZ, Lai YW, Yagoub D, Lev S, Hamey JJ, Pang CNI, Desmarini D, Chen Z, Djordjevic JT, Erce MA, Hart-Smith G, Wilkins MR. Knockout of the Hmt1p Arginine Methyltransferase in Saccharomyces cerevisiae Leads to the Dysregulation of Phosphate-associated Genes and Processes. Mol Cell Proteomics 2018; 17:2462-2479. [PMID: 30206180 PMCID: PMC6283299 DOI: 10.1074/mcp.ra117.000214] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 08/14/2018] [Indexed: 11/06/2022] Open
Abstract
Hmt1p is the predominant arginine methyltransferase in Saccharomyces cerevisiae Its substrate proteins are involved in transcription, transcriptional regulation, nucleocytoplasmic transport and RNA splicing. Hmt1p-catalyzed methylation can also modulate protein-protein interactions. Hmt1p is conserved from unicellular eukaryotes through to mammals where its ortholog, PRMT1, is lethal upon knockout. In yeast, however, the effect of knockout on the transcriptome and proteome has not been described. Transcriptome analysis revealed downregulation of phosphate-responsive genes in hmt1Δ, including acid phosphatases PHO5, PHO11, and PHO12, phosphate transporters PHO84 and PHO89 and the vacuolar transporter chaperone VTC3 Analysis of the hmt1Δ proteome revealed decreased abundance of phosphate-associated proteins including phosphate transporter Pho84p, vacuolar alkaline phosphatase Pho8p, acid phosphatase Pho3p and subunits of the vacuolar transporter chaperone complex Vtc1p, Vtc3p and Vtc4p. Consistent with this, phosphate homeostasis was dysregulated in hmt1Δ cells, showing decreased extracellular phosphatase levels and decreased total Pi in phosphate-depleted medium. In vitro, we showed that transcription factor Pho4p can be methylated at Arg-241, which could explain phosphate dysregulation in hmt1Δ if interplay exists with phosphorylation at Ser-242 or Ser-243, or if Arg-241 methylation affects the capacity of Pho4p to homodimerize or interact with Pho2p. However, the Arg-241 methylation site was not validated in vivo and the localization of a Pho4p-GFP fusion in hmt1Δ was not different from wild type. To our knowledge, this is the first study to reveal an association between Hmt1p and phosphate homeostasis and one which suggests a regulatory link between S-adenosyl methionine and intracellular phosphate.
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Affiliation(s)
- Samantha Z Chia
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Yu-Wen Lai
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Daniel Yagoub
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Sophie Lev
- Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute and Sydney Medical School, University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia
| | - Joshua J Hamey
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Chi Nam Ignatius Pang
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute and Sydney Medical School, University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia
| | - Zhiliang Chen
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Julianne T Djordjevic
- Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute and Sydney Medical School, University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia
| | - Melissa A Erce
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Gene Hart-Smith
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Marc R Wilkins
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
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Rasputin a decade on and more promiscuous than ever? A review of G3BPs. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:360-370. [PMID: 30595162 PMCID: PMC7114234 DOI: 10.1016/j.bbamcr.2018.09.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/29/2018] [Accepted: 09/04/2018] [Indexed: 12/12/2022]
Abstract
Ras-GTPase-activating protein (SH3 domain)-binding proteins (G3BPs, also known as Rasputin) are a family of RNA binding proteins that regulate gene expression in response to environmental stresses by controlling mRNA stability and translation. G3BPs appear to facilitate this activity through their role in stress granules for which they are considered a core component, however, it should be noted that not all stress granules contain G3BPs and this appears to be contextual depending on the environmental stress and the cell type. Although the role of G3BPs in stress granules appears to be one of its major roles, data also strongly suggests that they interact with mRNAs outside of stress granules to regulate gene expression. G3BPs have been implicated in several diseases including cancer progression, invasion, and metastasis as well as virus survival. There is now a body of evidence that suggests targeting of G3BPs could be explored as a form of cancer therapeutic. This review discusses the important discoveries and advancements made in the field of G3BPs biology over the last two decades including their roles in RNA stability, translational control of cellular transcripts, stress granule formation, cancer progression and its interactions with viruses during infection. An emerging theme for G3BPs is their ability to regulate gene expression in response to environmental stimuli, disease progression and virus infection making it an intriguing target for disease therapies. Triage of many cellular mRNA occurs via stress granules in a G3BP-dependant manner. G3BPs control intra cellular responses to viral infection. Transcript stability, degradation and translation are controlled by G3BPs. G3BPs can control cancer progression.
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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: 230] [Impact Index Per Article: 38.3] [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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25
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Raposo AE, Piller SC. Protein arginine methylation: an emerging regulator of the cell cycle. Cell Div 2018; 13:3. [PMID: 29568320 PMCID: PMC5859524 DOI: 10.1186/s13008-018-0036-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 03/13/2018] [Indexed: 12/19/2022] Open
Abstract
Protein arginine methylation is a common post-translational modification where a methyl group is added onto arginine residues of a protein to alter detection by its binding partners or regulate its activity. It is known to be involved in many biological processes, such as regulation of signal transduction, transcription, facilitation of protein–protein interactions, RNA splicing and transport. The enzymes responsible for arginine methylation, protein arginine methyltransferases (PRMTs), have been shown to methylate or associate with important regulatory proteins of the cell cycle and DNA damage repair pathways, such as cyclin D1, p53, p21 and the retinoblastoma protein. Overexpression of PRMTs resulting in aberrant methylation patterns in cancers often correlates with poor recovery prognosis. This indicates that protein arginine methylation is also an important regulator of the cell cycle, and consequently a target for cancer regulation. The effect of protein arginine methylation on the cell cycle and how this emerging key player of cell cycle regulation may be used in therapeutic strategies for cancer are the focus of this review.
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Affiliation(s)
- Anita E Raposo
- School of Science and Health, Western Sydney University, Penrith, NSW 2751 Australia
| | - Sabine C Piller
- School of Science and Health, Western Sydney University, Penrith, NSW 2751 Australia
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26
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Vizoso-Vázquez Á, Lamas-Maceiras M, González-Siso MI, Cerdán ME. Ixr1 Regulates Ribosomal Gene Transcription and Yeast Response to Cisplatin. Sci Rep 2018; 8:3090. [PMID: 29449612 PMCID: PMC5814428 DOI: 10.1038/s41598-018-21439-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 01/30/2018] [Indexed: 11/22/2022] Open
Abstract
Ixr1 is a Saccharomyces cerevisiae HMGB protein that regulates the hypoxic regulon and also controls the expression of other genes involved in the oxidative stress response or re-adaptation of catabolic and anabolic fluxes when oxygen is limiting. Ixr1 also binds with high affinity to cisplatin-DNA adducts and modulates DNA repair. The influence of Ixr1 on transcription in the absence or presence of cisplatin has been analyzed in this work. Ixr1 regulates other transcriptional factors that respond to nutrient availability or extracellular and intracellular stress stimuli, some controlled by the TOR pathway and PKA signaling. Ixr1 controls transcription of ribosomal RNAs and genes encoding ribosomal proteins or involved in ribosome assembly. qPCR, ChIP, and 18S and 25S rRNAs measurement have confirmed this function. Ixr1 binds directly to several promoters of genes related to rRNA transcription and ribosome biogenesis. Cisplatin treatment mimics the effect of IXR1 deletion on rRNA and ribosomal gene transcription, and prevents Ixr1 binding to specific promoters related to these processes.
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Affiliation(s)
- Ángel Vizoso-Vázquez
- Universidade da Coruña, Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Facultade de Ciencias, 15071 A, Coruña, Spain
| | - Mónica Lamas-Maceiras
- Universidade da Coruña, Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Facultade de Ciencias, 15071 A, Coruña, Spain
| | - M Isabel González-Siso
- Universidade da Coruña, Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Facultade de Ciencias, 15071 A, Coruña, Spain
| | - M Esperanza Cerdán
- Universidade da Coruña, Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Facultade de Ciencias, 15071 A, Coruña, Spain.
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Zhu L, Chang Y, Xing J, Tang X, Sheng X, Zhan W. Comparative proteomic analysis between two haemocyte subpopulations in shrimp Fenneropenaeus chinensis. FISH & SHELLFISH IMMUNOLOGY 2018; 72:325-333. [PMID: 28966142 DOI: 10.1016/j.fsi.2017.09.074] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 09/13/2017] [Accepted: 09/27/2017] [Indexed: 06/07/2023]
Abstract
In our previous work, granulocytes and hyalinocytes were successfully separated by immunomagnetic bead (IMB) method using monoclonal antibodies (mAbs) against granulocytes of shrimp (Fenneropenaeus chinensis). In order to elucidate the proteomic differentiation between granulocytes and hyalinocytes, in this paper, the differentially expressed proteins were analyzed between non-fixed/un-permeabilized (NFP) haemocytes and fixed/permeabilized (FP) haemocytes using two-dimensional gel electrophoresis (2-DE) combined with mass spectrometry (MS). Then the FP haemocytes were separated into two haemocyte subpopulations using IMB method, and the comparative proteome between granulocytes and hyalinocytes was investigated. The results showed that 10 differentially expressed protein spots were detected and identified as 4 proteins in the NFP haemocytes. Twenty one differentially expressed proteins were successfully identified between granulocytes and hyalinocytes, which include 4 unique expressed proteins in granulocytes, 4 significantly highly expressed proteins in granulocytes, and 13 significantly high expressed proteins in hyalinocytes. According to Gene Ontology annotation, the identified proteins between granulocytes and hyalinocytes were classified into six categories, including binding proteins, proteins involved in catalytic activity, enzyme regulator activity, structural molecule activity, translation regulator activity, and ungrouped proteins. Furthermore, quantitative PCR confirmed that the trend of transcription levels of three selected genes were consistent with the proteomic data from 2-DE. The results may lead to better understanding of the functions of haemocyte subpopulations.
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Affiliation(s)
- Lei Zhu
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, Qingdao 266003, PR China
| | - Yanhong Chang
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, Qingdao 266003, PR China
| | - Jing Xing
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, Qingdao 266003, PR China.
| | - Xiaoqian Tang
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, Qingdao 266003, PR China
| | - Xiuzhen Sheng
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, Qingdao 266003, PR China
| | - Wenbin Zhan
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, Qingdao 266003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, No. 1 Wenhai Road, Aoshanwei Town, Qingdao, China
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Brandariz-Núñez A, Zeng F, Lam QN, Jin H. Sbp1 modulates the translation of Pab1 mRNA in a poly(A)- and RGG-dependent manner. RNA (NEW YORK, N.Y.) 2018; 24:43-55. [PMID: 28986506 PMCID: PMC5733569 DOI: 10.1261/rna.062547.117] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 09/29/2017] [Indexed: 05/13/2023]
Abstract
RNA-binding protein Sbp1 facilitates the decapping pathway in mRNA metabolism and inhibits global mRNA translation by an unclear mechanism. Here we report molecular interactions responsible for Sbp1-mediated translation inhibition of mRNA encoding the polyadenosine-binding protein (Pab1), an essential translation factor that stimulates mRNA translation and inhibits mRNA decapping in eukaryotic cells. We demonstrate that the two distal RRMs of Sbp1 bind to the poly(A) sequence in the 5'UTR of the Pab1 mRNA specifically and cooperatively while the central RGG domain of the protein interacts directly with Pab1. Furthermore, methylation of arginines in the RGG domain abolishes the protein-protein interaction and the inhibitory effect of Sbp1 on translation initiation of Pab1 mRNA. Based on these results, the underlying mechanism for Sbp1-specific translational regulation is proposed. The functional differences of Sbp1 and RGG repeats alone on transcript-specific translation were observed, and a comparison of the results suggests the importance of remodeling the 5'UTR by RNA-binding proteins in mRNA translation.
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Affiliation(s)
- Alberto Brandariz-Núñez
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, USA
| | - Fuxing Zeng
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, USA
| | - Quan Ngoc Lam
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, USA
| | - Hong Jin
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, USA
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Roy R, Huang Y, Seckl MJ, Pardo OE. Emerging roles of hnRNPA1 in modulating malignant transformation. WILEY INTERDISCIPLINARY REVIEWS-RNA 2017; 8. [PMID: 28791797 DOI: 10.1002/wrna.1431] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/19/2017] [Accepted: 05/22/2017] [Indexed: 01/05/2023]
Abstract
Heterogeneous nuclear ribonucleoproteins (hnRNPs) are RNA-binding proteins associated with complex and diverse biological processes such as processing of heterogeneous nuclear RNAs (hnRNAs) into mature mRNAs, RNA splicing, transactivation of gene expression, and modulation of protein translation. hnRNPA1 is the most abundant and ubiquitously expressed member of this protein family and has been shown to be involved in multiple molecular events driving malignant transformation. In addition to selective mRNA splicing events promoting expression of specific protein variants, hnRNPA1 regulates the gene expression and translation of several key players associated with tumorigenesis and cancer progression. Here, we will summarize our current knowledge of the involvement of hnRNPA1 in cancer, including its roles in regulating cell proliferation, invasiveness, metabolism, adaptation to stress and immortalization. WIREs RNA 2017, 8:e1431. doi: 10.1002/wrna.1431 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Rajat Roy
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Yueyang Huang
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Michael J Seckl
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Olivier E Pardo
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
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Murn J, Shi Y. The winding path of protein methylation research: milestones and new frontiers. Nat Rev Mol Cell Biol 2017; 18:517-527. [PMID: 28512349 DOI: 10.1038/nrm.2017.35] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In 1959, while analysing the bacterial flagellar proteins, Ambler and Rees observed an unknown species of amino acid that they eventually identified as methylated lysine. Over half a century later, protein methylation is known to have a regulatory role in many essential cellular processes that range from gene transcription to signal transduction. However, the road to this now burgeoning research field was obstacle-ridden, not least because of the inconspicuous nature of the methyl mark itself. Here, we chronicle the milestone achievements and discuss the future of protein methylation research.
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Affiliation(s)
- Jernej Murn
- Department of Cell Biology, Harvard Medical School, and the Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, Massachusetts 02115, USA
| | - Yang Shi
- Department of Cell Biology, Harvard Medical School, and the Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, Massachusetts 02115, USA
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31
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Gao G, Dhar S, Bedford MT. PRMT5 regulates IRES-dependent translation via methylation of hnRNP A1. Nucleic Acids Res 2017; 45:4359-4369. [PMID: 28115626 PMCID: PMC5416833 DOI: 10.1093/nar/gkw1367] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 12/20/2016] [Accepted: 12/29/2016] [Indexed: 01/19/2023] Open
Abstract
The type II arginine methyltransferase PRMT5 is responsible for the symmetric dimethylation of histone to generate the H3R8me2s and H4R3me2s marks, which correlate with the repression of transcription. However, the protein level of a number of genes (MEP50, CCND1, MYC, HIF1a, MTIF and CDKN1B) are reported to be downregulated by the loss of PRMT5, while their mRNA levels remain unchanged, which is counterintuitive for PRMT5's proposed role as a transcription repressor. We noticed that the majority of the genes regulated by PRMT5, at the posttranscriptional level, express mRNA containing an internal ribosome entry site (IRES). Using an IRES-dependent reporter system, we established that PRMT5 facilitates the translation of a subset of IRES-containing genes. The heterogeneous nuclear ribonucleoprotein, hnRNP A1, is an IRES transacting factor (ITAF) that regulates the IRES-dependent translation of Cyclin D1 and c-Myc. We showed that hnRNP A1 is methylated by PRMT5 on two residues, R218 and R225, and that this methylation facilitates the interaction of hnRNP A1 with IRES RNA to promote IRES-dependent translation. This study defines a new role for PRMT5 regulation of cellular protein levels, which goes beyond the known functions of PRMT5 as a transcription and splicing regulator.
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Affiliation(s)
- Guozhen Gao
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Surbhi Dhar
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Mark T Bedford
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
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Eustache S, Créchet JB, Bouceba T, Nakayama JI, Tanaka M, Suzuki M, Woisard A, Tuffery P, Baouz S, Hountondji C. A Functional Role for the Monomethylated Gln-51 and Lys-53 Residues of the 49GGQTK53 Motif of eL42 from Human 80S Ribosomes. Open Biochem J 2017; 11:8-26. [PMID: 28567122 PMCID: PMC5418926 DOI: 10.2174/1874091x01711010008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 01/06/2017] [Accepted: 01/10/2017] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND We have previously demonstrated that the eukaryote-specific ribosomal protein eL42 of the human 80S ribosome contains seven monomethylated residues, among which are the Gln-51 and Lys-53 residues contained in the 47GFGGQTK53 sequence conserved in all eukaryotic 80S ribosomes. This sequence contains the methylated and universally conserved GGQ motif common for all class-1 translation termination factors responsible for stop codon recognition and for triggering the hydrolysis of the P site-bound peptidyl-tRNA. We have also recently reported a model of ribosomal ternary eL42-tRNA-eRF1 complex where specific regions of all three macromolecules (the comparably flexible GGQ domains of eRF1 and eL42 and the CCA-arm of tRNA) are involved in interactions. METHOD Here, we have studied the interactions between recombinant eL42 and eRF1 proteins and the tRNA substrate by means of the Biacore assay, using the wild-type eL42 protein, the eL42-Δ(GGQTK) mutant (the eL42 protein whose GGQTK motif has been deleted), the single Q51E and K53Q mutants (eL42-Q51E and eL42-K53Q, respectively), as well as the double Q51A/K53A mutant (eL42-Q51A/K53A). RESULTS Our results show that the monomethylated Gln-51 and Lys-53 residues contained in the 47GFGGQTK53 sequence of eL42 and the monomethylated GGQ motif of eRF1 represents the sites of interaction between these two proteins through hydrophobic contacts between methyl groups. We also demonstrate that the interactions between eL42 and tRNA or 28S rRNA are characterized by strong binding affinities (KD values in the nanomolar or picomolar range, respectively) which argue for specific interactions. Strong interactions between eL42 and tRNA are likely to be responsible for the decrease in the poly(U)-dependent poly(Phe) synthesis activity of human 80S or E. coli 70S ribosomes in the presence of added human recombinant eL42. It is proposed that the decrease of the activity of the ribosome is caused by the sequestration of the substrate Phe-tRNAPhe by the added eL42 protein. CONCLUSION Interactions between the monomethylated Gln-51 and Lys-53 residues of the 49GGQTK53 motif of the human eL42 protein and the methylated GGQ motif of eRF1 are likely to play a functional role on translating human 80S ribosomes.
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Affiliation(s)
- Stéphanie Eustache
- Sorbonne Universités, UPMC Univ Paris 06, Laboratoire “Enzymologie de l’ARN”, UPMC-UR6, (Tour 32), Case courrier 60 - 4, Place Jussieu, F-75252, Paris Cedex 05, France
- Université Paris-Diderot, Sorbonne-Paris-Cité, INSERM-UMR-S973 and RPBS, Paris, France
| | | | - Tahar Bouceba
- Sorbonne Universités, UPMC Univ Paris 06, Institut de Biologie Paris Seine (IBPS) Plateforme d’interactions moléculaires, CNRS-FR3631; 7, Quai Saint Bernard, F-75252, Paris Cedex 05, France
| | - Jun-ichi Nakayama
- Graduate School of Natural Sciences, Nagoya City University, 1 Yamanohata, Mizuho, Nagoya, Aichi 467-8501 Japan
| | - Mayo Tanaka
- Graduate School of Natural Sciences, Nagoya City University, 1 Yamanohata, Mizuho, Nagoya, Aichi 467-8501 Japan
| | - Mieko Suzuki
- Graduate School of Natural Sciences, Nagoya City University, 1 Yamanohata, Mizuho, Nagoya, Aichi 467-8501 Japan
| | - Anne Woisard
- Sorbonne Universités, UPMC Univ Paris 06, Laboratoire “Enzymologie de l’ARN”, UPMC-UR6, (Tour 32), Case courrier 60 - 4, Place Jussieu, F-75252, Paris Cedex 05, France
| | - Pierre Tuffery
- Université Paris-Diderot, Sorbonne-Paris-Cité, INSERM-UMR-S973 and RPBS, Paris, France
| | - Soria Baouz
- Sorbonne Universités, UPMC Univ Paris 06, Laboratoire “Enzymologie de l’ARN”, UPMC-UR6, (Tour 32), Case courrier 60 - 4, Place Jussieu, F-75252, Paris Cedex 05, France
| | - Codjo Hountondji
- Sorbonne Universités, UPMC Univ Paris 06, Laboratoire “Enzymologie de l’ARN”, UPMC-UR6, (Tour 32), Case courrier 60 - 4, Place Jussieu, F-75252, Paris Cedex 05, France
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Ariyachet C, Beißel C, Li X, Lorrey S, Mackenzie O, Martin PM, O'Brien K, Pholcharee T, Sim S, Krebber H, McBride AE. Post-translational modification directs nuclear and hyphal tip localization of Candida albicans mRNA-binding protein Slr1. Mol Microbiol 2017; 104:499-519. [PMID: 28187496 PMCID: PMC5405739 DOI: 10.1111/mmi.13643] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2017] [Indexed: 12/21/2022]
Abstract
The morphological transition of the opportunistic fungal pathogen Candida albicans from budding to hyphal growth has been implicated in its ability to cause disease in animal models. Absence of SR‐like RNA‐binding protein Slr1 slows hyphal formation and decreases virulence in a systemic candidiasis model, suggesting a role for post‐transcriptional regulation in these processes. SR (serine–arginine)‐rich proteins influence multiple steps in mRNA metabolism and their localization and function are frequently controlled by modification. We now demonstrate that Slr1 binds to polyadenylated RNA and that its intracellular localization is modulated by phosphorylation and methylation. Wildtype Slr1‐GFP is predominantly nuclear, but also co‐fractionates with translating ribosomes. The non‐phosphorylatable slr1‐6SA‐GFP protein, in which six serines in SR/RS clusters are substituted with alanines, primarily localizes to the cytoplasm in budding cells. Intriguingly, hyphal cells display a slr1‐6SA‐GFP focus at the tip near the Spitzenkörper, a vesicular structure involved in molecular trafficking to the tip. The presence of slr1‐6SA‐GFP hyphal tip foci is reduced in the absence of the mRNA‐transport protein She3, suggesting that unphosphorylated Slr1 associates with mRNA–protein complexes transported to the tip. The impact of SLR1 deletion on hyphal formation and function thus may be partially due to a role in hyphal mRNA transport.
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Affiliation(s)
| | - Christian Beißel
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften, Georg-August Universität Göttingen, Göttingen, Germany
| | - Xiang Li
- Biology Department, Bowdoin College, Brunswick, ME, 04011, USA
| | - Selena Lorrey
- Biology Department, Bowdoin College, Brunswick, ME, 04011, USA
| | | | | | | | | | - Sue Sim
- Biology Department, Bowdoin College, Brunswick, ME, 04011, USA
| | - Heike Krebber
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften, Georg-August Universität Göttingen, Göttingen, Germany
| | - Anne E McBride
- Biology Department, Bowdoin College, Brunswick, ME, 04011, USA
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Wall ML, Lewis SM. Methylarginines within the RGG-Motif Region of hnRNP A1 Affect Its IRES Trans-Acting Factor Activity and Are Required for hnRNP A1 Stress Granule Localization and Formation. J Mol Biol 2016; 429:295-307. [PMID: 27979648 DOI: 10.1016/j.jmb.2016.12.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/22/2016] [Accepted: 12/08/2016] [Indexed: 12/30/2022]
Abstract
Heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) is a stress granule-associated RNA-binding protein that plays a role in apoptosis and cellular stress recovery. HnRNP A1 is a major non-histone target of protein arginine methyltransferase 1, which asymmetrically dimethylates hnRNP A1 at several key arginine residues within its arginine-glycine-glycine (RGG)-motif region. Although arginine methylation is known to regulate general RNA binding of hnRNP A1 in vitro, the functional role of arginine methylation in hnRNP A1 cytoplasmic activity is unknown. To test the impact of key methylarginine residues on hnRNP A1 cytoplasmic activity and stress granule association, cytoplasmically restricted Flag-tagged mutants of hnRNP A1 were generated in which key methylarginine residues within the RGG-motif region were changed to either lysine or alanine. Lysine substitution, which mimics unmethylated arginine, resulted in a 40% increase in internal ribosome entry site trans-acting factor (ITAF) activity and the protein readily associates with stress granules. Alanine substitution resulted in a loss of ITAF activity and reduced mRNA binding. The alanine mutant also displays reduced stress granule association and suppresses stress granule formation. Our data suggest that arginine residues within the RGG-motif region are critical for hnRNP A1 cytoplasmic activities and that endogenous asymmetric dimethylation of the RGG-motif region suppresses hnRNP A1 ITAF activity in cells. Our findings indicate that methylarginine residues within the RGG-motif region of hnRNP A1 are important for its cytoplasmic activities and that hypomethylation and/or mutation of the RGG-motif region may contribute to the role of hnRNP A1 in diseases such as cancer.
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Affiliation(s)
- Michael L Wall
- Atlantic Cancer Research Institute, Moncton, New Brunswick, Canada
| | - Stephen M Lewis
- Atlantic Cancer Research Institute, Moncton, New Brunswick, Canada; Department of Microbiology & Immunology, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Biology, University of New Brunswick, Saint John, New Brunswick, Canada; Department of Chemistry & Biochemistry, Université de Moncton, Moncton, New Brunswick, Canada.
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Zander G, Hackmann A, Bender L, Becker D, Lingner T, Salinas G, Krebber H. mRNA quality control is bypassed for immediate export of stress-responsive transcripts. Nature 2016; 540:593-596. [PMID: 27951587 DOI: 10.1038/nature20572] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 10/24/2016] [Indexed: 12/24/2022]
Abstract
Cells grow well only in a narrow range of physiological conditions. Surviving extreme conditions requires the instantaneous expression of chaperones that help to overcome stressful situations. To ensure the preferential synthesis of these heat-shock proteins, cells inhibit transcription, pre-mRNA processing and nuclear export of non-heat-shock transcripts, while stress-specific mRNAs are exclusively exported and translated. How cells manage the selective retention of regular transcripts and the simultaneous rapid export of heat-shock mRNAs is largely unknown. In Saccharomyces cerevisiae, the shuttling RNA adaptor proteins Npl3, Gbp2, Hrb1 and Nab2 are loaded co-transcriptionally onto growing pre-mRNAs. For nuclear export, they recruit the export-receptor heterodimer Mex67-Mtr2 (TAP-p15 in humans). Here we show that cellular stress induces the dissociation of Mex67 and its adaptor proteins from regular mRNAs to prevent general mRNA export. At the same time, heat-shock mRNAs are rapidly exported in association with Mex67, without the need for adapters. The immediate co-transcriptional loading of Mex67 onto heat-shock mRNAs involves Hsf1, a heat-shock transcription factor that binds to heat-shock-promoter elements in stress-responsive genes. An important difference between the export modes is that adaptor-protein-bound mRNAs undergo quality control, whereas stress-specific transcripts do not. In fact, regular mRNAs are converted into uncontrolled stress-responsive transcripts if expressed under the control of a heat-shock promoter, suggesting that whether an mRNA undergoes quality control is encrypted therein. Under normal conditions, Mex67 adaptor proteins are recruited for RNA surveillance, with only quality-controlled mRNAs allowed to associate with Mex67 and leave the nucleus. Thus, at the cost of error-free mRNA formation, heat-shock mRNAs are exported and translated without delay, allowing cells to survive extreme situations.
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Affiliation(s)
- Gesa Zander
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften, Georg-August Universität Göttingen, Göttingen, Germany
| | - Alexandra Hackmann
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften, Georg-August Universität Göttingen, Göttingen, Germany
| | - Lysann Bender
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften, Georg-August Universität Göttingen, Göttingen, Germany
| | - Daniel Becker
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften, Georg-August Universität Göttingen, Göttingen, Germany
| | - Thomas Lingner
- Transkriptomanalyselabor, Institut für Entwicklungsbiochemie, Georg-August Universität Göttingen, Göttingen, Germany
| | - Gabriela Salinas
- Transkriptomanalyselabor, Institut für Entwicklungsbiochemie, Georg-August Universität Göttingen, Göttingen, Germany
| | - Heike Krebber
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften, Georg-August Universität Göttingen, Göttingen, Germany
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pUL69 of Human Cytomegalovirus Recruits the Cellular Protein Arginine Methyltransferase 6 via a Domain That Is Crucial for mRNA Export and Efficient Viral Replication. J Virol 2015; 89:9601-15. [PMID: 26178996 DOI: 10.1128/jvi.01399-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 07/02/2015] [Indexed: 02/06/2023] Open
Abstract
UNLABELLED The regulatory protein pUL69 of human cytomegalovirus acts as a viral mRNA export factor, facilitating the cytoplasmic accumulation of unspliced RNA via interaction with the cellular mRNA export factor UAP56. Here we provide evidence for a posttranslational modification of pUL69 via arginine methylation within the functionally important N terminus. First, we demonstrated a specific immunoprecipitation of full-length pUL69 as well as pUL69aa1-146 by a mono/dimethylarginine-specific antibody. Second, we observed a specific electrophoretic mobility shift upon overexpression of the catalytically active protein arginine methyltransferase 6 (PRMT6). Third, a direct interaction of pUL69 and PRMT6 was confirmed by yeast two-hybrid and coimmunoprecipitation analyses. We mapped the PRMT6 interaction motif to the pUL69 N terminus and identified critical amino acids within the arginine-rich R1 box of pUL69 that were crucial for PRMT6 and/or UAP56 recruitment. In order to test the impact of putative methylation substrates on the functions of pUL69, we constructed various pUL69 derivatives harboring arginine-to-alanine substitutions and tested them for RNA export activity. Thus, we were able to discriminate between arginines within the R1 box of pUL69 that were crucial for UAP56/PRMT6-interaction and/or mRNA export activity. Remarkably, nuclear magnetic resonance (NMR) analyses revealed the same α-helical structures for pUL69 sequences encoding either the wild type R1/R2 boxes or a UAP56/PRMT6 binding-deficient derivative, thereby excluding the possibility that R/A amino acid substitutions within R1 affected the secondary structure of pUL69. We therefore conclude that the pUL69 N terminus is methylated by PRMT6 and that this critically affects the functions of pUL69 for efficient mRNA export and replication of human cytomegalovirus. IMPORTANCE The UL69 protein of human cytomegalovirus is a multifunctional regulatory protein that acts as a viral RNA export factor with a critical role for efficient replication. Here, we demonstrate that pUL69 is posttranslationally modified via arginine methylation and that the protein methyltransferase PRMT6 mediates this modification. Furthermore, arginine residues with a crucial function for RNA export and for binding of the cellular RNA export factor UAP56 as well as PRMT6 were mapped within the arginine-rich R1 motif of pUL69. Importantly, we demonstrated that mutation of those arginines did not alter the secondary structure of R1, suggesting that they may serve as critical methylation substrates. In summary, our study reveals a novel posttranslational modification of pUL69 which has a significant impact on the function of this important viral regulatory protein. Since PRMTs appear to be amenable to selective inhibition by small molecules, this may constitute a novel target for antiviral therapy.
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Abstract
Protein arginine methyltransferases (PRMTs) are a family of enzymes that can methylate protein arginine residues. PRMTs’ substrates include histones and a variety of non-histone proteins. Previous studies have shown that yeast Hmt1 is a type I PRMT and methylates histone H4 arginine 3 and several mRNA-binding proteins. Hmt1 forms dimers or oligomers, but how dimerization or oligomerization affects its activity remains largely unknown. We now report that Hmt1 can methylate histone H3 arginine 2 (H3R2) in vitro. The dimerization but not hexamerization is essential for Hmt1’s activity. Interestingly, the methyltransferase activity of Hmt1 on histone H3R2 requires reciprocal contributions from two Hmt1 molecules. Our results suggest an intermolecular trans-complementary mechanism by which Hmt1 dimer methylates its substrates.
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Ladror DT, Frey BL, Scalf M, Levenstein ME, Artymiuk JM, Smith LM. Methylation of yeast ribosomal protein S2 is elevated during stationary phase growth conditions. Biochem Biophys Res Commun 2014; 445:535-41. [PMID: 24486316 DOI: 10.1016/j.bbrc.2014.01.040] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Accepted: 01/14/2014] [Indexed: 01/12/2023]
Abstract
Ribosomes, as the center of protein translation in the cell, require careful regulation via multiple pathways. While regulation of ribosomal synthesis and function has been widely studied on the transcriptional and translational "levels," the biological roles of ribosomal post-translational modifications (PTMs) are largely not understood. Here, we explore this matter by using quantitative mass spectrometry to compare the prevalence of ribosomal methylation and acetylation for yeast in the log phase and the stationary phase of growth. We find that of the 27 modified peptides identified, two peptides experience statistically significant changes in abundance: a 1.9-fold decrease in methylation for k(Me)VSGFKDEVLETV of ribosomal protein S1B (RPS1B), and a 10-fold increase in dimethylation for r(DiMe)GGFGGR of ribosomal protein S2 (RPS2). While the biological role of RPS1B methylation has largely been unexplored, RPS2 methylation is a modification known to have a role in processing and export of ribosomal RNA. This suggests that yeast in the stationary phase increase methylation of RPS2 in order to regulate ribosomal synthesis. These results demonstrate the utility of mass spectrometry for quantifying dynamic changes in ribosomal PTMs.
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Affiliation(s)
- Daniel T Ladror
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Brian L Frey
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Mark Scalf
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Mark E Levenstein
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Jacklyn M Artymiuk
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Lloyd M Smith
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA.
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Lau HT, Lewis KA, Ong SE. Quantifying in vivo, site-specific changes in protein methylation with SILAC. Methods Mol Biol 2014; 1188:161-175. [PMID: 25059611 DOI: 10.1007/978-1-4939-1142-4_12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Interest in protein methylation has grown rapidly in recent years. Mass spectrometry-based proteomics is ideally suited to characterize protein modifications, but the multiplicity of methylated residues and the lack of efficient methods to enrich methylated proteins have limited the proteomic identification of protein methylation sites. In this protocol, we compare two metabolic labeling approaches, stable isotope labeling by amino acids in cell culture (SILAC) and its variant heavy methyl SILAC, for studying protein methylation. Instead of heavy lysine and arginine in the typical SILAC experiment, heavy methyl SILAC uses (13)C, (2)H methionine as the labeling amino acid. As cells convert methionine to S-adenosylmethionine, heavy methyl SILAC encodes a 4 Da mass tag for each methyl group, distinguishing between degrees of methylation is possible from mass difference alone. We provide a protocol for SILAC-based analyses of protein methylation and highlight the strengths and weaknesses of each method for targeted and proteomic analyses.
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Affiliation(s)
- Ho-Tak Lau
- Department of Pharmacology, University of Washington, 1959 NE Pacific Street, 357280, Seattle, WA, 98195, USA
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Monosome formation during translation initiation requires the serine/arginine-rich protein Npl3. Mol Cell Biol 2013; 33:4811-23. [PMID: 24100011 DOI: 10.1128/mcb.00873-13] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The yeast shuttling serine/arginine-rich protein Npl3 is required for the export of mRNAs and pre-60S ribosomal subunits from the nucleus to the cytoplasm. Here, we report a novel function of Npl3 in translation initiation. A mutation in its C terminus that prevents its dimerization (npl3Δ100) is lethal to cells and leads to translational defects, as shown by [(35)S]methionine incorporation assays and a hypersensitivity to the translational inhibitor cycloheximide. Moreover, this Npl3 mutant shows halfmers in polysomal profiles that are indicative of defects in monosome formation. Strikingly, the loss of the ability of Npl3 to dimerize does not affect mRNA and pre-60S export. In fact, the mRNA and rRNA binding capacities of npl3Δ100 and wild-type Npl3 are similar. Intriguingly, overexpression of the dimerization domain of Npl3 disturbs dimer formation and results in a dominant-negative effect, reflected in growth defects and a halfmer formation phenotype. In addition, we found specific genetic interactions with the ribosomal subunit joining factors Rpl10 and eukaryotic translation initiation factor 5B/Fun12 and detected a substantially decreased binding of npl3Δ100 to the Rpl10-containing complex. These findings indicate an essential novel function for Npl3 in the cytoplasm, which supports monosome formation for translation initiation.
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Friend LR, Landsberg MJ, Nouwens AS, Wei Y, Rothnagel JA, Smith R. Arginine methylation of hnRNP A2 does not directly govern its subcellular localization. PLoS One 2013; 8:e75669. [PMID: 24098712 PMCID: PMC3787039 DOI: 10.1371/journal.pone.0075669] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 08/16/2013] [Indexed: 11/18/2022] Open
Abstract
The hnRNP A/B paralogs A1, A2/B1 and A3 are key components of the nuclear 40S hnRNP core particles. Despite a high degree of sequence similarity, increasing evidence suggests they perform additional, functionally distinct roles in RNA metabolism. Here we identify and study the functional consequences of differential post-translational modification of hnRNPs A1, A2 and A3. We show that while arginine residues in the RGG box domain of hnRNP A1 and A3 are almost exhaustively, asymmetrically dimethylated, hnRNP A2 is dimethylated at only a single residue (Arg-254) and this modification is conserved across cell types. It has been suggested that arginine methylation regulates the nucleocytoplasmic distribution of hnRNP A/B proteins. However, we show that transfected cells expressing an A2R254A point mutant exhibit no difference in subcellular localization. Similarly, immunostaining and mass spectrometry of endogenous hnRNP A2 in transformed cells reveals a naturally-occurring pool of unmethylated protein but an exclusively nuclear pattern of localization. Our results suggest an alternative role for post-translational arginine methylation of hnRNPs and offer further evidence that the hnRNP A/B paralogs are not functionally redundant.
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Affiliation(s)
- Lexie R. Friend
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Michael J. Landsberg
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland, Australia
| | - Amanda S. Nouwens
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Ying Wei
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Joseph A. Rothnagel
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland, Australia
| | - Ross Smith
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
- * E-mail:
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Jean-Philippe J, Paz S, Caputi M. hnRNP A1: the Swiss army knife of gene expression. Int J Mol Sci 2013; 14:18999-9024. [PMID: 24065100 PMCID: PMC3794818 DOI: 10.3390/ijms140918999] [Citation(s) in RCA: 207] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 09/02/2013] [Accepted: 09/04/2013] [Indexed: 12/31/2022] Open
Abstract
Eukaryotic cells express a large variety of RNA binding proteins (RBPs), with diverse affinities and specificities towards target RNAs. These proteins play a crucial role in almost every aspect of RNA biogenesis, expression and function. The heterogeneous nuclear ribonucleoproteins (hnRNPs) are a complex and diverse family of RNA binding proteins. hnRNPs display multiple functions in the processing of heterogeneous nuclear RNAs into mature messenger RNAs. hnRNP A1 is one of the most abundant and ubiquitously expressed members of this protein family. hnRNP A1 plays multiple roles in gene expression by regulating major steps in the processing of nascent RNA transcripts. The transcription, splicing, stability, export through nuclear pores and translation of cellular and viral transcripts are all mechanisms modulated by this protein. The diverse functions played by hnRNP A1 are not limited to mRNA biogenesis, but extend to the processing of microRNAs, telomere maintenance and the regulation of transcription factor activity. Genomic approaches have recently uncovered the extent of hnRNP A1 roles in the development and differentiation of living organisms. The aim of this review is to highlight recent developments in the study of this protein and to describe its functions in cellular and viral gene expression and its role in human pathologies.
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Affiliation(s)
- Jacques Jean-Philippe
- Charles E. Schmidt College of Medicine, Florida Atlantic University, 777 Glades Rd, Boca Raton, FL 33431, USA.
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Low JK, Hart-Smith G, Erce MA, Wilkins MR. Analysis of the Proteome of Saccharomyces cerevisiae for Methylarginine. J Proteome Res 2013; 12:3884-99. [DOI: 10.1021/pr400556c] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Jason K.K. Low
- Systems Biology Laboratory, School of Biotechnology
and Biomolecular Sciences, The University of New South Wales, NSW 2052 Sydney, Australia
| | - Gene Hart-Smith
- Systems Biology Laboratory, School of Biotechnology
and Biomolecular Sciences, The University of New South Wales, NSW 2052 Sydney, Australia
| | - Melissa A. Erce
- Systems Biology Laboratory, School of Biotechnology
and Biomolecular Sciences, The University of New South Wales, NSW 2052 Sydney, Australia
| | - Marc R. Wilkins
- Systems Biology Laboratory, School of Biotechnology
and Biomolecular Sciences, The University of New South Wales, NSW 2052 Sydney, Australia
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Jackson CA, Yadav N, Min S, Li J, Milliman EJ, Qu J, Chen YC, Yu MC. Proteomic analysis of interactors for yeast protein arginine methyltransferase Hmt1 reveals novel substrate and insights into additional biological roles. Proteomics 2013; 12:3304-14. [PMID: 22997150 DOI: 10.1002/pmic.201200132] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 09/06/2012] [Accepted: 09/10/2012] [Indexed: 01/07/2023]
Abstract
Protein arginine methylation is a PTM catalyzed by an evolutionarily conserved family of enzymes called protein arginine methyltransferases (PRMTs), with PRMT1 being the most conserved member of this enzyme family. This modification has emerged to be an important regulator of protein functions. To better understand the role of PRMTs in cellular pathways and functions, we have carried out a proteomic profiling experiment to comprehensively identify the physical interactors of Hmt1, the budding yeast homolog for human PRMT1. Using a dual-enzymatic digestion linear trap quadrupole/Orbitrap proteomic strategy, we identified a total of 108 proteins that specifically copurify with Hmt1 by tandem affinity purification. A reverse coimmunoprecipitation experiment was used to confirm Hmt1's physical association with Bre5, Mtr4, Snf2, Sum1, and Ssd1, five proteins that were identified as Hmt1-specific interactors in multiple biological replicates. To determine whether the identified Hmt1-interactors had the potential to act as an Hmt1 substrate, we used published bioinformatics algorithms that predict the presence and location of potential methylarginines for each identified interactor. One of the top hits from this analysis, Snf2, was experimentally confirmed as a robust substrate of Hmt1 in vitro. Overall, our data provide a feasible proteomic approach that aid in the better understanding of PRMT1's roles within a cell.
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Affiliation(s)
- Christopher A Jackson
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York 14260, USA
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Schmidt K, Butler JS. Nuclear RNA surveillance: role of TRAMP in controlling exosome specificity. WILEY INTERDISCIPLINARY REVIEWS-RNA 2013; 4:217-31. [PMID: 23417976 DOI: 10.1002/wrna.1155] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The advent of high-throughput sequencing technologies has revealed that pervasive transcription generates RNAs from nearly all regions of eukaryotic genomes. Normally, these transcripts undergo rapid degradation by a nuclear RNA surveillance system primarily featuring the RNA exosome. This multimeric protein complex plays a critical role in the efficient turnover and processing of a vast array of RNAs in the nucleus. Despite its initial discovery over a decade ago, important questions remain concerning the mechanisms that recruit and activate the nuclear exosome. Specificity and modulation of exosome activity requires additional protein cofactors, including the conserved TRAMP polyadenylation complex. Recent studies suggest that helicase and RNA-binding subunits of TRAMP direct RNA substrates for polyadenylation, which enhances their degradation by Dis3/Rrp44 and Rrp6, the two exosome-associated ribonucleases. These findings indicate that the exosome and TRAMP have evolved highly flexible functions that allow recognition of a wide range of RNA substrates. This flexibility provides the nuclear RNA surveillance system with the ability to regulate the levels of a broad range of coding and noncoding RNAs, which results in profound effects on gene expression, cellular development, gene silencing, and heterochromatin formation. This review summarizes recent findings on the nuclear RNA surveillance complexes, and speculates upon possible mechanisms for TRAMP-mediated substrate recognition and exosome activation.
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Affiliation(s)
- Karyn Schmidt
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester Medical Center, Rochester, NY, USA
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Lee KM, Tarn WY. Coupling pre-mRNA processing to transcription on the RNA factory assembly line. RNA Biol 2013; 10:380-90. [PMID: 23392244 DOI: 10.4161/rna.23697] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
It has been well-documented that nuclear processing of primary transcripts of RNA polymerase II occurs co-transcriptionally and is functionally coupled to transcription. Moreover, increasing evidence indicates that transcription influences pre-mRNA splicing and even several post-splicing RNA processing events. In this review, we discuss the issues of how RNA polymerase II modulates co-transcriptional RNA processing events via its carboxyl terminal domain, and the protein domains involved in coupling of transcription and RNA processing events. In addition, we describe how transcription influences the expression or stability of mRNAs through the formation of distinct mRNP complexes. Finally, we delineate emerging findings that chromatin modifications function in the regulation of RNA processing steps, especially splicing, in addition to transcription. Overall, we provide a comprehensive view that transcription could integrate different control systems, from epigenetic to post-transcriptional control, for efficient gene expression.
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Affiliation(s)
- Kuo-Ming Lee
- Institute of Biomedical Sciences; Academia Sinica; Taipei, Taiwan
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Abstract
For most of our 25,000 genes, the removal of introns by pre-messenger RNA (pre-mRNA) splicing represents an essential step toward the production of functional messenger RNAs (mRNAs). Alternative splicing of a single pre-mRNA results in the production of different mRNAs. Although complex organisms use alternative splicing to expand protein function and phenotypic diversity, patterns of alternative splicing are often altered in cancer cells. Alternative splicing contributes to tumorigenesis by producing splice isoforms that can stimulate cell proliferation and cell migration or induce resistance to apoptosis and anticancer agents. Cancer-specific changes in splicing profiles can occur through mutations that are affecting splice sites and splicing control elements, and also by alterations in the expression of proteins that control splicing decisions. Recent progress in global approaches that interrogate splicing diversity should help to obtain specific splicing signatures for cancer types. The development of innovative approaches for annotating and reprogramming splicing events will more fully establish the essential contribution of alternative splicing to the biology of cancer and will hopefully provide novel targets and anticancer strategies. Metazoan genes are usually made up of several exons interrupted by introns. The introns are removed from the pre-mRNA by RNA splicing. In conjunction with other maturation steps, such as capping and polyadenylation, the spliced mRNA is then transported to the cytoplasm to be translated into a functional protein. The basic mechanism of splicing requires accurate recognition of each extremity of each intron by the spliceosome. Introns are identified by the binding of U1 snRNP to the 5' splice site and the U2AF65/U2AF35 complex to the 3' splice site. Following these interactions, other proteins and snRNPs are recruited to generate the complete spliceosomal complex needed to excise the intron. While many introns are constitutively removed by the spliceosome, other splice junctions are not used systematically, generating the phenomenon of alternative splicing. Alternative splicing is therefore the process by which a single species of pre-mRNA can be matured to produce different mRNA molecules (Fig. 1). Depending on the number and types of alternative splicing events, a pre-mRNA can generate from two to several thousands different mRNAs leading to the production of a corresponding number of proteins. It is now believed that the expression of at least 70 % of human genes is subjected to alternative splicing, implying an enormous contribution to proteomic diversity, and by extension, to the development and the evolution of complex animals. Defects in splicing have been associated with human diseases (Caceres and Kornblihtt, Trends Genet 18(4):186-93, 2002, Cartegni et al., Nat Rev Genet 3(4):285-98, 2002, Pagani and Baralle, Nat Rev Genet 5(5):389-96, 2004), including cancer (Brinkman, Clin Biochem 37(7):584-94, 2004, Venables, Bioessays 28(4):378-86, 2006, Srebrow and Kornblihtt, J Cell Sci 119(Pt 13):2635-2641, 2006, Revil et al., Bull Cancer 93(9):909-919, 2006, Venables, Transworld Res Network, 2006, Pajares et al., Lancet Oncol 8(4):349-57, 2007, Skotheim and Nees, Int J Biochem Cell Biol 39:1432-1449, 2007). Numerous studies have now confirmed the existence of specific differences in the alternative splicing profiles between normal and cancer tissues. Although there are a few cases where specific mutations are the primary cause for these changes, global alterations in alternative splicing in cancer cells may be primarily derived from changes in the expression of RNA-binding proteins that control splice site selection. Overall, these cancer-specific differences in alternative splicing offer an immense potential to improve the diagnosis and the prognosis of cancer. This review will focus on the functional impact of cancer-associated alternative splicing variants, the molecular determinants that alter the splicing decisions in cancer cells, and future therapeutic strategies.
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Milliman EJ, Hu Z, Yu MC. Genomic insights of protein arginine methyltransferase Hmt1 binding reveals novel regulatory functions. BMC Genomics 2012; 13:728. [PMID: 23268696 PMCID: PMC3568405 DOI: 10.1186/1471-2164-13-728] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 12/21/2012] [Indexed: 01/21/2023] Open
Abstract
Background Protein arginine methylation is a post-translational modification involved in important biological processes such as transcription and RNA processing. This modification is catalyzed by both type I and II protein arginine methyltransferases (PRMTs). One of the most conserved type I PRMTs is PRMT1, the homolog of which is Hmt1 in Saccharomyces cerevisiae. Hmt1 has been shown to play a role in various gene expression steps, such as promoting the dynamics of messenger ribonucleoprotein particle (mRNP) biogenesis, pre-mRNA splicing, and silencing of chromatin. To determine the full extent of Hmt1’s involvement during gene expression, we carried out a genome-wide location analysis for Hmt1. Results A comprehensive genome-wide binding profile for Hmt1 was obtained by ChIP-chip using NimbleGen high-resolution tiling microarrays. Of the approximately 1000 Hmt1-binding sites found, the majority fall within or proximal to an ORF. Different occupancy patterns of Hmt1 across genes with different transcriptional rates were found. Interestingly, Hmt1 occupancy is found at a number of other genomic features such as tRNA and snoRNA genes, thereby implicating a regulatory role in the biogenesis of these non-coding RNAs. RNA hybridization analysis shows that Hmt1 loss-of-function mutants display higher steady-state tRNA abundance relative to the wild-type. Co-immunoprecipitation studies demonstrate that Hmt1 interacts with the TFIIIB component Bdp1, suggesting a mechanism for Hmt1 in modulating RNA Pol III transcription to regulate tRNA production. Conclusions The genome-wide binding profile of Hmt1 reveals multiple potential new roles for Hmt1 in the control of eukaryotic gene expression, especially in the realm of non-coding RNAs. The data obtained here will provide an important blueprint for future mechanistic studies on the described occupancy relationship for genomic features bound by Hmt1.
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Affiliation(s)
- Eric J Milliman
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, NY 14260, USA
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Bekenstein U, Soreq H. Heterogeneous nuclear ribonucleoprotein A1 in health and neurodegenerative disease: from structural insights to post-transcriptional regulatory roles. Mol Cell Neurosci 2012; 56:436-46. [PMID: 23247072 DOI: 10.1016/j.mcn.2012.12.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Revised: 12/02/2012] [Accepted: 12/06/2012] [Indexed: 12/14/2022] Open
Abstract
Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a family of conserved nuclear proteins that associate with nascent RNA polymerase II transcripts to yield hnRNP particles, playing key roles in mRNA metabolism, DNA-related functions and microRNA biogenesis. HnRNPs accompany transcripts from stages of transcriptional regulation through splicing and post-transcriptional regulation, and are believed to affect the majority of expressed genes in mammals. Most hnRNP mRNA transcripts undergo alternative splicing and post-translational modifications, to yield a remarkable diversity of proteins with numerous functional elements that work in concert in their multiple functions. Therefore, mis-regulation of hnRNPs leads to different maladies. Here, we focus on the role of one of the best-known members of this protein family, hnRNP A1 in RNA metabolism, and address recent works that note its multileveled involvement in several neurodegenerative disorders. Initially discovered as a DNA binding protein, hnRNP A1 includes two RNA recognition motifs, and post-translational modifications of these and other regions in this multifunctional protein alter both its nuclear pore shuttling properties and its RNA interactions and affect transcription, mRNA splicing and microRNA biogenesis. HnRNP A1 plays several key roles in neuronal functioning and its depletion, either due to debilitated cholinergic neurotransmission or under autoimmune reactions causes drastic changes in RNA metabolism. Consequently, hnRNP A1 decline contributes to the severity of symptoms in several neurodegenerative diseases, including Alzheimer's disease (AD), spinal muscular atrophy (SMA), fronto-temporal lobar degeneration (FTLD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), hereditary spastic paraparesis (HSP) and HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP). At the translational level, these properties of hnRNP A1 led to massive research efforts aimed at developing RNA-targeted therapeutic tools such as splicing-modulating oligonucleotides with promising pharmaceutical potential. HnRNP A1 thus presents an intriguing example for the complexity and importance of heteronuclear ribonucleoproteins in health and disease. This article is part of a Special Issue entitled 'RNA and splicing regulation in neurodegeneration'.
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Affiliation(s)
- Uriya Bekenstein
- Dept of Biological Chemistry, The Life Sciences Institute and The Edmond and Lily Safra Center of Brain Science, The Hebrew University of Jerusalem, 91904, Israel
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Low JKK, Wilkins MR. Protein arginine methylation in Saccharomyces cerevisiae. FEBS J 2012; 279:4423-43. [PMID: 23094907 DOI: 10.1111/febs.12039] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 10/10/2012] [Accepted: 10/19/2012] [Indexed: 11/27/2022]
Abstract
Recent research has implicated arginine methylation as a major regulator of cellular processes, including transcription, translation, nucleocytoplasmic transport, signalling, DNA repair, RNA processing and splicing. Arginine methylation is evolutionarily conserved, and it is now thought that it may rival other post-translational modifications such as phosphorylation in terms of its occurrence in the proteome. In addition, multiple recent examples demonstrate an exciting new theme: the interplay between methylation and other post-translational modifications such as phosphorylation. In this review, we summarize our current understanding of arginine methylation and the recent advances made, with a focus on the lower eukaryote Saccharomyces cerevisiae. We cover the types of methylated proteins, their responsible methyltransferases, where and how the effects of arginine methylation are seen in the cell, and, finally, discuss the conservation of the biological function of methylarginines between S. cerevisiae and mammals.
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Affiliation(s)
- Jason K K Low
- Systems Biology Laboratory, School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, Australia
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