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Zhang X, Duan Y, Li S, Zhang Z, Peng L, Ma X, Wang T, Xiang S, Chen G, Zhou D, Lu D, Qian M, Wang Z. CRISPR screening identifies PRMT1 as a key pro-ferroptotic gene via a two-layer regulatory mechanism. Cell Rep 2024; 43:114662. [PMID: 39178116 DOI: 10.1016/j.celrep.2024.114662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 07/10/2024] [Accepted: 08/06/2024] [Indexed: 08/25/2024] Open
Abstract
Ferroptosis is a form of nonapoptotic cell death characterized by iron-dependent peroxidation of polyunsaturated phospholipids. However, much remains unknown about the regulators of ferroptosis. Here, using CRISPR-Cas9-mediated genetic screening, we identify protein arginine methyltransferase 1 (PRMT1) as a crucial promoter of ferroptosis. We find that PRMT1 decreases the expression of solute carrier family 7 member 11 (SLC7A11) to limit the abundance of intracellular glutathione (GSH). Moreover, we show that PRMT1 interacts with ferroptosis suppressor protein 1 (FSP1), a GSH-independent ferroptosis suppressor, to inhibit the membrane localization and enzymatic activity of FSP1 through arginine dimethylation at R316, thus reducing CoQ10H2 content and inducing ferroptosis sensitivity. Importantly, genetic depletion or pharmacological inhibition of PRMT1 in mice prevents ferroptotic events in the liver and improves the overall survival under concanavalin A (ConA) exposure. Hence, our findings suggest that PRMT1 is a key regulator of ferroptosis and a potential target for antiferroptosis therapeutics.
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Affiliation(s)
- Xin Zhang
- State Key Laboratory of Natural Medicines, Department of Life Science and Technology, China Pharmaceutical University, Nanjing 211198, China; Guangdong Provincial Key Laboratory of Regional Immunity and Diseases, Cancer Research Center, Department of Pharmacology, Shenzhen University Medical School, Shenzhen 518055, China
| | - Yajun Duan
- State Key Laboratory of Natural Medicines, Department of Life Science and Technology, China Pharmaceutical University, Nanjing 211198, China
| | - Su Li
- State Key Laboratory of Natural Medicines, Department of Life Science and Technology, China Pharmaceutical University, Nanjing 211198, China
| | - Zhenyuan Zhang
- State Key Laboratory of Natural Medicines, Department of Life Science and Technology, China Pharmaceutical University, Nanjing 211198, China
| | - Linyuan Peng
- State Key Laboratory of Natural Medicines, Department of Life Science and Technology, China Pharmaceutical University, Nanjing 211198, China
| | - Xiaoyu Ma
- State Key Laboratory of Natural Medicines, Department of Life Science and Technology, China Pharmaceutical University, Nanjing 211198, China
| | - Tianzhi Wang
- State Key Laboratory of Natural Medicines, Department of Life Science and Technology, China Pharmaceutical University, Nanjing 211198, China
| | - Siliang Xiang
- State Key Laboratory of Natural Medicines, Department of Life Science and Technology, China Pharmaceutical University, Nanjing 211198, China
| | - Guo Chen
- School of Biopharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Danyang Zhou
- Department of Respiratory, Nanjing First Hospital, China Pharmaceutical University, Nanjing 210012, China
| | - Desheng Lu
- Guangdong Provincial Key Laboratory of Regional Immunity and Diseases, Cancer Research Center, Department of Pharmacology, Shenzhen University Medical School, Shenzhen 518055, China.
| | - Minxian Qian
- State Key Laboratory of Natural Medicines, Department of Life Science and Technology, China Pharmaceutical University, Nanjing 211198, China.
| | - Zhongyuan Wang
- State Key Laboratory of Natural Medicines, Department of Life Science and Technology, China Pharmaceutical University, Nanjing 211198, China.
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Breunig K, Lei X, Montalbano M, Guardia GDA, Ostadrahimi S, Alers V, Kosti A, Chiou J, Klein N, Vinarov C, Wang L, Li M, Song W, Kraus WL, Libich DS, Tiziani S, Weintraub ST, Galante PAF, Penalva LOF. SERBP1 interacts with PARP1 and is present in PARylation-dependent protein complexes regulating splicing, cell division, and ribosome biogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.22.586270. [PMID: 38585848 PMCID: PMC10996453 DOI: 10.1101/2024.03.22.586270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
RNA binding proteins (RBPs) containing intrinsically disordered regions (IDRs) are present in diverse molecular complexes where they function as dynamic regulators. Their characteristics promote liquid-liquid phase separation (LLPS) and the formation of membraneless organelles such as stress granules and nucleoli. IDR-RBPs are particularly relevant in the nervous system and their dysfunction is associated with neurodegenerative diseases and brain tumor development. SERBP1 is a unique member of this group, being mostly disordered and lacking canonical RNA-binding domains. Using a proteomics approach followed by functional analysis, we defined SERBP1's interactome. We uncovered novel SERBP1 roles in splicing, cell division, and ribosomal biogenesis and showed its participation in pathological stress granules and Tau aggregates in Alzheimer's disease brains. SERBP1 preferentially interacts with other G-quadruplex (G4) binders, implicated in different stages of gene expression, suggesting that G4 binding is a critical component of SERBP1 function in different settings. Similarly, we identified important associations between SERBP1 and PARP1/polyADP-ribosylation (PARylation). SERBP1 interacts with PARP1 and its associated factors and influences PARylation. Moreover, protein complexes in which SERBP1 participates contain mostly PARylated proteins and PAR binders. Based on these results, we propose a feedback regulatory model in which SERBP1 influences PARP1 function and PARylation, while PARylation modulates SERBP1 functions and participation in regulatory complexes.
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3
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Tong C, Chang X, Qu F, Bian J, Wang J, Li Z, Xu X. Overview of the development of protein arginine methyltransferase modulators: Achievements and future directions. Eur J Med Chem 2024; 267:116212. [PMID: 38359536 DOI: 10.1016/j.ejmech.2024.116212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/31/2024] [Accepted: 01/31/2024] [Indexed: 02/17/2024]
Abstract
Protein methylation is a post-translational modification (PTM) that organisms undergo. This process is considered a part of epigenetics research. In recent years, there has been an increasing interest in protein methylation, particularly histone methylation, as research has advanced. Methylation of histones is a dynamic process that is subject to fine control by histone methyltransferases and demethylases. In addition, many non-histone proteins also undergo methylation, and these modifications collectively regulate physiological phenomena, including RNA transcription, translation, signal transduction, DNA damage response, and cell cycle. Protein arginine methylation is a crucial aspect of protein methylation, which plays a significant role in regulating the cell cycle and repairing DNA. It is also linked to various diseases. Therefore, protein arginine methyltransferases (PRMTs) that are involved in this process have gained considerable attention as a potential therapeutic target for treating diseases. Several PRMT inhibitors are in phase I/II clinical trials. This paper aims to introduce the structure, biochemical functions, and bioactivity assays of PRMTs. Additionally, we will review the structure-function of currently popular PRMT inhibitors. Through the analysis of various data on known PRMT inhibitors, we hope to provide valuable assistance for future drug design and development.
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Affiliation(s)
- Chao Tong
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjin, 211198, China
| | - Xiujin Chang
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjin, 211198, China
| | - Fangui Qu
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjin, 211198, China
| | - Jinlei Bian
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjin, 211198, China
| | - Jubo Wang
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjin, 211198, China.
| | - Zhiyu Li
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjin, 211198, China.
| | - Xi Xu
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjin, 211198, China.
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4
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Lu L, Ye Z, Zhang R, Olsen JV, Yuan Y, Mao Y. ETD-Based Proteomic Profiling Improves Arginine Methylation Identification and Reveals Novel PRMT5 Substrates. J Proteome Res 2024; 23:1014-1027. [PMID: 38272855 DOI: 10.1021/acs.jproteome.3c00724] [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] [Indexed: 01/27/2024]
Abstract
Protein arginine methylations are important post-translational modifications (PTMs) in eukaryotes, regulating many biological processes. However, traditional collision-based mass spectrometry methods inevitably cause neutral losses of methylarginines, preventing the deep mining of biologically important sites. Herein we developed an optimized mass spectrometry workflow based on electron-transfer dissociation (ETD) with supplemental activation for proteomic profiling of arginine methylation in human cells. Using symmetric dimethylarginine (sDMA) as an example, we show that the ETD-based optimized workflow significantly improved the identification and site localization of sDMA. Quantitative proteomics identified 138 novel sDMA sites as potential PRMT5 substrates in HeLa cells. Further biochemical studies on SERBP1, a newly identified PRMT5 substrate, confirmed the coexistence of sDMA and asymmetric dimethylarginine in the central RGG/RG motif, and loss of either methylation caused increased the recruitment of SERBP1 to stress granules under oxidative stress. Overall, our optimized workflow not only enabled the identification and localization of extensive, nonoverlapping sDMA sites in human cells but also revealed novel PRMT5 substrates whose sDMA may play potentially important biological functions.
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Affiliation(s)
- Lingzi Lu
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, Sun Yat-sen University, Guangzhou 510006, China
| | - Zilu Ye
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Rou Zhang
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, Sun Yat-sen University, Guangzhou 510006, China
| | - Jesper V Olsen
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Yanqiu Yuan
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, Sun Yat-sen University, Guangzhou 510006, China
| | - Yang Mao
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, Sun Yat-sen University, Guangzhou 510006, China
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5
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Zhou J, Wang T, Zhang H, Liu J, Wei P, Xu R, Yan Q, Chen G, Li W, Gao SJ, Lu C. KSHV vIL-6 promotes SIRT3-induced deacetylation of SERBP1 to inhibit ferroptosis and enhance cellular transformation by inducing lipoyltransferase 2 mRNA degradation. PLoS Pathog 2024; 20:e1012082. [PMID: 38470932 PMCID: PMC10959363 DOI: 10.1371/journal.ppat.1012082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 03/22/2024] [Accepted: 02/27/2024] [Indexed: 03/14/2024] Open
Abstract
Ferroptosis, a defensive strategy commonly employed by the host cells to restrict pathogenic infections, has been implicated in the development and therapeutic responses of various types of cancer. However, the role of ferroptosis in oncogenic Kaposi's sarcoma-associated herpesvirus (KSHV)-induced cancers remains elusive. While a growing number of non-histone proteins have been identified as acetylation targets, the functions of these modifications have yet to be revealed. Here, we show KSHV reprogramming of host acetylation proteomics following cellular transformation of rat primary mesenchymal precursor. Among them, SERPINE1 mRNA binding protein 1 (SERBP1) deacetylation is increased and required for KSHV-induced cellular transformation. Mechanistically, KSHV-encoded viral interleukin-6 (vIL-6) promotes SIRT3 deacetylation of SERBP1, preventing its binding to and protection of lipoyltransferase 2 (Lipt2) mRNA from mRNA degradation resulting in ferroptosis. Consequently, a SIRT3-specific inhibitor, 3-TYP, suppresses KSHV-induced cellular transformation by inducing ferroptosis. Our findings unveil novel roles of vIL-6 and SERBP1 deacetylation in regulating ferroptosis and KSHV-induced cellular transformation, and establish the vIL-6-SIRT3-SERBP1-ferroptosis pathways as a potential new therapeutic target for KSHV-associated cancers.
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Affiliation(s)
- Jing Zhou
- Department of Microbiology, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Tianjiao Wang
- Department of Microbiology, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Haoran Zhang
- Department of Microbiology, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Jianhong Liu
- Department of Pathology, Changzhou Third People’s Hospital, Changzhou, People’s Republic of China
| | - Pengjun Wei
- Department of Microbiology, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Ruoqi Xu
- Department of Microbiology, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Qin Yan
- Department of Microbiology, Nanjing Medical University, Nanjing, People’s Republic of China
- Changzhou Medical Center, Nanjing Medical University, Nanjing, People’s Republic of China
- Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Guochun Chen
- Department of Infectious Diseases, Changzhou Third People’s Hospital, Changzhou, People’s Republic of China
| | - Wan Li
- Department of Microbiology, Nanjing Medical University, Nanjing, People’s Republic of China
- Changzhou Medical Center, Nanjing Medical University, Nanjing, People’s Republic of China
- Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Shou-Jiang Gao
- Tumor Virology Program, UPMC Hillman Cancer Center, and Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Chun Lu
- Department of Microbiology, Nanjing Medical University, Nanjing, People’s Republic of China
- Changzhou Medical Center, Nanjing Medical University, Nanjing, People’s Republic of China
- Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, People’s Republic of China
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6
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Wang F, Wang L, Gan S, Feng S, Ouyang S, Wang X, Yuan S. SERBP1 Promotes Stress Granule Clearance by Regulating 26S Proteasome Activity and G3BP1 Ubiquitination and Protects Male Germ Cells from Thermostimuli Damage. RESEARCH (WASHINGTON, D.C.) 2023; 6:0091. [PMID: 37223481 PMCID: PMC10202183 DOI: 10.34133/research.0091] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 02/15/2023] [Indexed: 04/18/2024]
Abstract
Stress granules (SGs) are membraneless cytoplasmic condensates that dynamically assemble in response to various stressors and reversibly disassemble after stimulus removal; however, the mechanisms underlying SG dynamics and their physiological roles in germ cell development are elusive. Here, we show that SERBP1 (SERPINE1 mRNA binding protein 1) is a universal SG component and conserved regulator of SG clearance in somatic and male germ cells. SERBP1 interacts with the SG core component G3BP1 and 26S proteasome proteins PSMD10 and PSMA3 and recruits them to SGs. In the absence of SERBP1, reduced 20S proteasome activity, mislocalized valosin containing protein (VCP) and Fas associated factor family member 2 (FAF2), and diminished K63-linked polyubiquitination of G3BP1 during the SG recovery period were observed. Interestingly, the depletion of SERBP1 in testicular cells in vivo causes increased germ cell apoptosis upon scrotal heat stress. Accordingly, we propose that a SERBP1-mediated mechanism regulates 26S proteasome activity and G3BP1 ubiquitination to facilitate SG clearance in both somatic and germ cell lines.
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Affiliation(s)
- Fengli Wang
- Institute of Reproductive Health, Tongji Medical College,
Huazhong University of Science and Technology, Wuhan 430030, China
| | - Lingjuan Wang
- Institute of Reproductive Health, Tongji Medical College,
Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shiming Gan
- Institute of Reproductive Health, Tongji Medical College,
Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shenglei Feng
- Institute of Reproductive Health, Tongji Medical College,
Huazhong University of Science and Technology, Wuhan 430030, China
| | - Sijin Ouyang
- Institute of Reproductive Health, Tongji Medical College,
Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiaoli Wang
- Institute of Reproductive Health, Tongji Medical College,
Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shuiqiao Yuan
- Institute of Reproductive Health, Tongji Medical College,
Huazhong University of Science and Technology, Wuhan 430030, China
- Laboratory of Animal Center,
Huazhong University of Science and Technology, Wuhan 430030, China
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7
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Identification and Characterization of Glycine- and Arginine-Rich Motifs in Proteins by a Novel GAR Motif Finder Program. Genes (Basel) 2023; 14:genes14020330. [PMID: 36833257 PMCID: PMC9957100 DOI: 10.3390/genes14020330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 01/17/2023] [Accepted: 01/17/2023] [Indexed: 01/31/2023] Open
Abstract
Glycine- and arginine-rich (GAR) motifs with different combinations of RG/RGG repeats are present in many proteins. The nucleolar rRNA 2'-O-methyltransferase fibrillarin (FBL) contains a conserved long N-terminal GAR domain with more than 10 RGG plus RG repeats separated by specific amino acids, mostly phenylanalines. We developed a GAR motif finder (GMF) program based on the features of the GAR domain of FBL. The G(0,3)-X(0,1)-R-G(1,2)-X(0,5)-G(0,2)-X(0,1)-R-G(1,2) pattern allows the accommodation of extra-long GAR motifs with continuous RG/RGG interrupted by polyglycine or other amino acids. The program has a graphic interface and can easily output the results as .csv and .txt files. We used GMF to show the characteristics of the long GAR domains in FBL and two other nucleolar proteins, nucleolin and GAR1. GMF analyses can illustrate the similarities and also differences between the long GAR domains in the three nucleolar proteins and motifs in other typical RG/RGG-repeat-containing proteins, specifically the FET family members FUS, EWS, and TAF15 in position, motif length, RG/RGG number, and amino acid composition. We also used GMF to analyze the human proteome and focused on the ones with at least 10 RGG plus RG repeats. We showed the classification of the long GAR motifs and their putative correlation with protein/RNA interactions and liquid-liquid phase separation. The GMF algorithm can facilitate further systematic analyses of the GAR motifs in proteins and proteomes.
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8
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Poole E, Sinclair J. Latency-associated upregulation of SERBP1 is important for the recruitment of transcriptional repressors to the viral major immediate early promoter of human cytomegalovirus during latent carriage. Front Microbiol 2022; 13:999290. [PMID: 36504797 PMCID: PMC9729347 DOI: 10.3389/fmicb.2022.999290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 11/02/2022] [Indexed: 11/25/2022] Open
Abstract
Suppression of human cytomegalovirus (HCMV) major immediate early gene (IE) expression from the viral major immediate early promoter (MIEP) is known to be crucial for the establishment and maintenance of HCMV latency in myeloid progenitor cells and their undifferentiated derivatives. This suppression of the MIEP during latent infection is known to result from epigenetic histone modification imparting a repressive chromatin structure around the MIEP in undifferentiated myeloid cells. In contrast, reactivation, resulting from, e.g., myeloid cell differentiation, is associated with activatory chromatin marks around the MIEP. Recently, recruitment of the transcriptional repressor SETDB1, via KAP1, to latent HCMV genomes was shown to be involved in latency-associated MIEP suppression in CD34+ progenitor cells. KAP1 is also known to associate with Chromodomain-helicase-DNA-binding protein 3 (CHD3) as part of the NuRD complex which can aid transcriptional silencing. We now show that the cellular protein Plasminogen activator inhibitor 1 RNA-binding protein (SERBP1), a known interactor of CHD3, is significantly upregulated during HCMV latency and that this protein is required for MIEP suppression during latent infection of myeloid cells. We further show that SERBP1 mediates CHD3 association with the MIEP as well as KAP1 association with viral genomic DNA. We suggest that SERBP1 functions as a scaffold protein to recruit transcriptional repressors to the latent viral genome and to mediate transcriptional silencing of the MIEP during latent carriage.
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Affiliation(s)
- Emma Poole
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
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9
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Ren J, Zhang Z, Zong Z, Zhang L, Zhou F. Emerging Implications of Phase Separation in Cancer. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202855. [PMID: 36117111 PMCID: PMC9631093 DOI: 10.1002/advs.202202855] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 08/26/2022] [Indexed: 05/19/2023]
Abstract
In eukaryotic cells, biological activities are executed in distinct cellular compartments or organelles. Canonical organelles with membrane-bound structures are well understood. Cells also inherently contain versatile membrane-less organelles (MLOs) that feature liquid or gel-like bodies. A biophysical process termed liquid-liquid phase separation (LLPS) elucidates how MLOs form through dynamic biomolecule assembly. LLPS-related molecules often have multivalency, which is essential for low-affinity inter- or intra-molecule interactions to trigger phase separation. Accumulating evidence shows that LLPS concentrates and organizes desired molecules or segregates unneeded molecules in cells. Thus, MLOs have tunable functional specificity in response to environmental stimuli and metabolic processes. Aberrant LLPS is widely associated with several hallmarks of cancer, including sustained proliferative signaling, growth suppressor evasion, cell death resistance, telomere maintenance, DNA damage repair, etc. Insights into the molecular mechanisms of LLPS provide new insights into cancer therapeutics. Here, the current understanding of the emerging concepts of LLPS and its involvement in cancer are comprehensively reviewed.
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Affiliation(s)
- Jiang Ren
- School of MedicineZhejiang University City CollegeHangzhou215123China
- The Eighth Affiliated HospitalSun Yat‐sen UniversityShenzhen518033China
| | - Zhenyu Zhang
- Department of NeurosurgeryThe First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenan450003China
| | - Zhi Zong
- MOE Key Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling NetworkLife Sciences InstituteZhejiang UniversityHangzhou310058China
| | - Long Zhang
- MOE Key Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling NetworkLife Sciences InstituteZhejiang UniversityHangzhou310058China
- International Biomed‐X Research Center, Second Affiliated Hospital of Zhejiang University School of MedicineZhejiang UniversityHangzhouChina
- Cancer CenterZhejiang UniversityHangzhou215123China
| | - Fangfang Zhou
- School of MedicineZhejiang University City CollegeHangzhou215123China
- Institutes of Biology and Medical SciencesSoochow UniversitySuzhou215123China
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10
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Smith PR, Pandit SC, Loerch S, Campbell ZT. The space between notes: emerging roles for translationally silent ribosomes. Trends Biochem Sci 2022; 47:477-491. [PMID: 35246374 PMCID: PMC9106873 DOI: 10.1016/j.tibs.2022.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/31/2022] [Accepted: 02/04/2022] [Indexed: 01/02/2023]
Abstract
In addition to their central functions in translation, ribosomes can adopt inactive structures that are fully assembled yet devoid of mRNA. We describe how the abundance of idle eukaryotic ribosomes is influenced by a broad range of biological conditions spanning viral infection, nutrient deprivation, and developmental cues. Vacant ribosomes may provide a means to exclude ribosomes from translation while also shielding them from degradation, and the variable identity of factors that occlude ribosomes may impart distinct functionality. We propose that regulated changes in the balance of idle and active ribosomes provides a means to fine-tune translation. We provide an overview of idle ribosomes, describe what is known regarding their function, and highlight questions that may clarify their biological roles.
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Affiliation(s)
- Patrick R Smith
- The University of Texas at Dallas, Department of Biological Sciences, Richardson, TX, USA
| | - Sapna C Pandit
- University of California, Santa Cruz, Department of Chemistry and Biochemistry, Santa Cruz, CA, USA
| | - Sarah Loerch
- University of California, Santa Cruz, Department of Chemistry and Biochemistry, Santa Cruz, CA, USA
| | - Zachary T Campbell
- The University of Texas at Dallas, Department of Biological Sciences, Richardson, TX, USA; The Center for Advanced Pain Studies (CAPS), University of Texas at Dallas, Richardson, TX, USA.
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11
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Barbato C, Frisone P, Braccini L, D’Aguanno S, Pieroni L, Ciotti MT, Catalanotto C, Cogoni C, Ruberti F. Silencing of Ago-2 Interacting Protein SERBP1 Relieves KCC2 Repression by miR-92 in Neurons. Cells 2022; 11:1052. [PMID: 35326503 PMCID: PMC8947033 DOI: 10.3390/cells11061052] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/11/2022] [Accepted: 03/18/2022] [Indexed: 12/13/2022] Open
Abstract
RNA-binding proteins (RBPs) play important roles in modulating miRNA-mediated mRNA target repression. Argonaute2 (Ago2) is an essential component of the RNA-induced silencing complex (RISC) that plays a central role in silencing mechanisms via small non-coding RNA molecules known as siRNAs and miRNAs. Small RNAs loaded into Argonaute proteins catalyze endoribonucleolytic cleavage of target RNAs or recruit factors responsible for translational silencing and mRNA target destabilization. In previous studies we have shown that KCC2, a neuronal Cl (-) extruding K (+) Cl (-) co-transporter 2, is regulated by miR-92 in neuronal cells. Searching for Ago2 partners by immunoprecipitation and LC-MS/MS analysis, we isolated among other proteins the Serpine mRNA binding protein 1 (SERBP1) from SH-SY5Y neuroblastoma cells. Exploring the role of SERBP1 in miRNA-mediated gene silencing in SH-SY5Y cells and primary hippocampal neurons, we demonstrated that SERBP1 silencing regulates KCC2 expression through the 3' untranslated region (UTR). In addition, we found that SERBP1 as well as Ago2/miR-92 complex bind to KCC2 3'UTR. Finally, we demonstrated the attenuation of miR-92-mediated repression of KCC2 3'UTR by SERBP1 silencing. These findings advance our knowledge regarding the miR-92-mediated modulation of KCC2 translation in neuronal cells and highlight SERBP1 as a key component of this gene regulation.
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Affiliation(s)
- Christian Barbato
- Institute of Biochemistry and Cell Biology, National Research Council CNR, Department of Sense Organs, University of Rome Sapienza, 00161 Roma, Italy
| | - Paola Frisone
- Institute of Biochemistry and Cell Biology CNR, Campus A. Buzzati-Traverso, 00015 Monterotondo (RM), Italy; (P.F.); (M.T.C.)
- Department of Molecular Medicine, University of Rome Sapienza, 00161 Roma, Italy; (L.B.); (C.C.)
| | - Laura Braccini
- Department of Molecular Medicine, University of Rome Sapienza, 00161 Roma, Italy; (L.B.); (C.C.)
| | - Simona D’Aguanno
- Preclinical Models and New Therapeutic Agents Unit, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy;
| | - Luisa Pieroni
- Department of Experimental Neuroscience, Proteomics and Metabolomics Unit, IRCCS-Fondazione Santa Lucia, 00143 Rome, Italy;
| | - Maria Teresa Ciotti
- Institute of Biochemistry and Cell Biology CNR, Campus A. Buzzati-Traverso, 00015 Monterotondo (RM), Italy; (P.F.); (M.T.C.)
| | - Caterina Catalanotto
- Department of Molecular Medicine, University of Rome Sapienza, 00161 Roma, Italy; (L.B.); (C.C.)
| | - Carlo Cogoni
- Department of Molecular Medicine, University of Rome Sapienza, 00161 Roma, Italy; (L.B.); (C.C.)
| | - Francesca Ruberti
- Institute of Biochemistry and Cell Biology CNR, Campus A. Buzzati-Traverso, 00015 Monterotondo (RM), Italy; (P.F.); (M.T.C.)
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12
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A genetically-encoded crosslinker screen identifies SERBP1 as a PKCε substrate influencing translation and cell division. Nat Commun 2021; 12:6934. [PMID: 34836941 PMCID: PMC8626422 DOI: 10.1038/s41467-021-27189-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 11/08/2021] [Indexed: 01/09/2023] Open
Abstract
The PKCε-regulated genome protective pathway provides transformed cells a failsafe to successfully complete mitosis. Despite the necessary role for Aurora B in this programme, it is unclear whether its requirement is sufficient or if other PKCε cell cycle targets are involved. To address this, we developed a trapping strategy using UV-photocrosslinkable amino acids encoded in the PKCε kinase domain. The validation of the mRNA binding protein SERBP1 as a PKCε substrate revealed a series of mitotic events controlled by the catalytic form of PKCε. PKCε represses protein translation, altering SERBP1 binding to the 40 S ribosomal subunit and promoting the assembly of ribonucleoprotein granules containing SERBP1, termed M-bodies. Independent of Aurora B, SERBP1 is shown to be necessary for chromosome segregation and successful cell division, correlating with M-body formation. This requirement for SERBP1 demonstrates that Aurora B acts in concert with translational regulation in the PKCε-controlled pathway exerting genome protection.
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13
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Lenard AJ, Hutten S, Zhou Q, Usluer S, Zhang F, Bourgeois BMR, Dormann D, Madl T. Phosphorylation Regulates CIRBP Arginine Methylation, Transportin-1 Binding and Liquid-Liquid Phase Separation. Front Mol Biosci 2021; 8:689687. [PMID: 34738012 PMCID: PMC8562343 DOI: 10.3389/fmolb.2021.689687] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 10/01/2021] [Indexed: 12/20/2022] Open
Abstract
Arginine-glycine(-glycine) (RG/RGG) regions are highly abundant in RNA-binding proteins and involved in numerous physiological processes. Aberrant liquid-liquid phase separation (LLPS) and stress granule (SGs) association of RG/RGG regions in the cytoplasm have been implicated in several neurodegenerative disorders. LLPS and SG association of these proteins is regulated by the interaction with nuclear import receptors, such as transportin-1 (TNPO1), and by post-translational arginine methylation. Strikingly, many RG/RGG proteins harbour potential phosphorylation sites within or close to their arginine methylated regions, indicating a regulatory role. Here, we studied the role of phosphorylation within RG/RGG regions on arginine methylation, TNPO1-binding and LLPS using the cold-inducible RNA-binding protein (CIRBP) as a paradigm. We show that the RG/RGG region of CIRBP is in vitro phosphorylated by serine-arginine protein kinase 1 (SRPK1), and discovered two novel phosphorylation sites in CIRBP. SRPK1-mediated phosphorylation of the CIRBP RG/RGG region impairs LLPS and binding to TNPO1 in vitro and interferes with SG association in cells. Furthermore, we uncovered that arginine methylation of the CIRBP RG/RGG region regulates in vitro phosphorylation by SRPK1. In conclusion, our findings indicate that LLPS and TNPO1-mediated chaperoning of RG/RGG proteins is regulated through an intricate interplay of post-translational modifications.
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Affiliation(s)
- Aneta J. Lenard
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Saskia Hutten
- Johannes Gutenberg-Universität (JGU) Mainz, Faculty of Biology, Mainz, Germany
- BioMedical Center, Cell Biology, Ludwig-Maximilians-Universität (LMU) München, Martinsried, Germany
| | - Qishun Zhou
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Sinem Usluer
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Fangrong Zhang
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Benjamin M. R. Bourgeois
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Dorothee Dormann
- Johannes Gutenberg-Universität (JGU) Mainz, Faculty of Biology, Mainz, Germany
- BioMedical Center, Cell Biology, Ludwig-Maximilians-Universität (LMU) München, Martinsried, Germany
- Institute of Molecular Biology (IMB), Mainz, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Tobias Madl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
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14
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Baudin A, Moreno-Romero AK, Xu X, Selig EE, Penalva LOF, Libich DS. Structural Characterization of the RNA-Binding Protein SERBP1 Reveals Intrinsic Disorder and Atypical RNA Binding Modes. Front Mol Biosci 2021; 8:744707. [PMID: 34631798 PMCID: PMC8497785 DOI: 10.3389/fmolb.2021.744707] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 09/07/2021] [Indexed: 11/18/2022] Open
Abstract
RNA binding proteins (RBPs) are essential for critical biological processes such as translation regulation and mRNA processing, and misfunctions of these proteins are associated with diseases such as cancer and neurodegeneration. SERBP1 (SERPINE1 mRNA Binding Protein 1) is an RBP that comprises two RG/RGG repeat regions yet lacks other recognizable RNA-binding motifs. It is involved in mRNA maturation, and translational regulation. It was initially identified as a hyaluronic acid binding protein, but recent studies have identified central roles for SERBP1 in brain function and development, especially neurogenesis and synaptogenesis. SERBP1 regulates One-carbon metabolism and epigenetic modification of histones, and increased SERBP1 expression in cancers such as leukemia, ovarian, prostate, liver and glioblastoma is correlated with poor patient outcomes. Despite these important regulatory roles for SERBP1, little is known about its structural and dynamic properties, nor about the molecular mechanisms governing its interaction with mRNA. Here, we define SERBP1 as an intrinsically disordered protein, containing highly conserved elements that were shown to be functionally important. The RNA binding activity of SERBP1 was explored using solution NMR and other biophysical techniques. The outcome of these experiments revealed that SERBP1 preferentially samples compact conformations including a central, stable α-helix and show that SERBP1 recognizes G-rich RNA sequences at the C-terminus involving the RGG box and neighboring residues. Despite the role in RNA recognition, the RGG boxes do not seem to stabilize the central helix and the central helix does not participate in RNA binding. Further, SERBP1 undergoes liquid-liquid phase separation, mediated by salt and RNA, and both RGG boxes are necessary for the efficient formation of condensed phases. Together, these results provide a foundation for understanding the molecular mechanisms of SERBP1 functions in physiological and pathological processes.
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Affiliation(s)
- Antoine Baudin
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.,Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Alma K Moreno-Romero
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.,Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Xiaoping Xu
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.,Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Emily E Selig
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.,Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Luiz O F Penalva
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.,Department of Cell Systems and Anatomy, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - David S Libich
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.,Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
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15
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Ruta V, Pagliarini V, Sette C. Coordination of RNA Processing Regulation by Signal Transduction Pathways. Biomolecules 2021; 11:biom11101475. [PMID: 34680108 PMCID: PMC8533259 DOI: 10.3390/biom11101475] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/01/2021] [Accepted: 10/05/2021] [Indexed: 02/06/2023] Open
Abstract
Signal transduction pathways transmit the information received from external and internal cues and generate a response that allows the cell to adapt to changes in the surrounding environment. Signaling pathways trigger rapid responses by changing the activity or localization of existing molecules, as well as long-term responses that require the activation of gene expression programs. All steps involved in the regulation of gene expression, from transcription to processing and utilization of new transcripts, are modulated by multiple signal transduction pathways. This review provides a broad overview of the post-translational regulation of factors involved in RNA processing events by signal transduction pathways, with particular focus on the regulation of pre-mRNA splicing, cleavage and polyadenylation. The effects of several post-translational modifications (i.e., sumoylation, ubiquitination, methylation, acetylation and phosphorylation) on the expression, subcellular localization, stability and affinity for RNA and protein partners of many RNA-binding proteins are highlighted. Moreover, examples of how some of the most common signal transduction pathways can modulate biological processes through changes in RNA processing regulation are illustrated. Lastly, we discuss challenges and opportunities of therapeutic approaches that correct RNA processing defects and target signaling molecules.
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Affiliation(s)
- Veronica Ruta
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (V.R.); (V.P.)
- Organoids Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy
| | - Vittoria Pagliarini
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (V.R.); (V.P.)
- Organoids Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy
| | - Claudio Sette
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (V.R.); (V.P.)
- Laboratory of Neuroembryology, IRCCS Fondazione Santa Lucia, 00143 Rome, Italy
- Correspondence:
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16
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Baudin A, Xu X, Libich DS. The 1H, 15N and 13C resonance assignments of the C-terminal domain of Serpine mRNA binding protein 1 (SERBP1). BIOMOLECULAR NMR ASSIGNMENTS 2021; 15:461-466. [PMID: 34436734 PMCID: PMC9990118 DOI: 10.1007/s12104-021-10046-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
SERBP1 is a multifunctional mRNA-binding protein that has been shown to play a regulatory role in a number of biological processes such as thrombosis, DNA damage repair, and the cellular response to nutrient deprivation. Additionally, SERBP1 is upregulated in glioblastoma, leukemia as well as liver, prostrate and ovarian cancers where it has been implicated in metastatic disease and poor patient outcomes. SERBP1 binds target mRNA, stabilizing and regulating the post-translational expression of the transcript. Since SERBP1 lacks canonical RNA-binding motifs such as RRM domains or zinc fingers, its target recognition and binding mechanisms are not well understood. Recent reports suggest that it is capable of recognizing both RNA sequence motifs and structured domains. Here we report the production and purification of the intrinsically disordered C-terminal domain of SERBP1, the assignment of the 1H, 13C, 15N backbone resonances of the protein by solution-state NMR, and secondary structure predictions. We show that the protein is not entirely disordered and identify an α-helix that was stable under the experimental conditions. This work is the first step toward understanding the structural basis underpinning the molecular mechanisms of SERBP1 functions, particularly interactions with mRNA targets.
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Affiliation(s)
- Antoine Baudin
- Department of Biochemistry and Structural Biology, and Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, 8403 Floyd Curl Dr., San Antonio, TX, 78229, USA
| | - Xiaoping Xu
- Department of Biochemistry and Structural Biology, and Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, 8403 Floyd Curl Dr., San Antonio, TX, 78229, USA
| | - David S Libich
- Department of Biochemistry and Structural Biology, and Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, 8403 Floyd Curl Dr., San Antonio, TX, 78229, USA.
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17
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Liu X, Xiong Y, Zhang C, Lai R, Liu H, Peng R, Fu T, Liu Q, Fang X, Mann S, Tan W. G-Quadruplex-Induced Liquid-Liquid Phase Separation in Biomimetic Protocells. J Am Chem Soc 2021; 143:11036-11043. [PMID: 34270902 DOI: 10.1021/jacs.1c03627] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Biomolecular condensates comprised of specific proteins and nucleic acids are now recognized as one of the key organizing mechanisms in eukaryotic cells. However, the specific roles played by the nucleic acid secondary structure and sequence in biomolecular phase separation are still not clear. Here, utilizing giant membrane vesicles (GMVs) as a protocell model, we found that single-stranded DNA (ssDNA) with a parallel G-quadruplex structure could functionally cooperate with a G-quadruplex-binding protein to form speckle-like puncta inside the GMVs. The clustering behavior is dependent on the structural diversity of G-quadruplexes, and the reversible clustering behavior implicated a new pathway in dynamically regulating the formation of biomolecular condensates. This finding represents a potential link between G-quadruplex-binding proteins and the resulting G-quadruplex-mediated biomolecular phase separation, which would gain insight into a wide range of biological processes associated with nucleic acid-modulated phase separation inside living cells.
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Affiliation(s)
- Xuejiao Liu
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
| | - Yansong Xiong
- Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Chunjuan Zhang
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
| | - Rongji Lai
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
| | - Hui Liu
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
| | - Ruizi Peng
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China.,The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Basic Medicine and Cancer (IBMC), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China
| | - Ting Fu
- The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Basic Medicine and Cancer (IBMC), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China
| | - Qiaoling Liu
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
| | - Xiaohong Fang
- Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Basic Medicine and Cancer (IBMC), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China
| | - Stephen Mann
- Centre for Protolife Research and Centre for Organized Matter Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom.,Max Planck-Bristol Centre for Minimal Biology, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom.,School of Materials Science and Engineering, Institute of Molecular Medicine (IMM), Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Weihong Tan
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China.,The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Basic Medicine and Cancer (IBMC), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China.,School of Materials Science and Engineering, Institute of Molecular Medicine (IMM), Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
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18
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Cai T, Yu Z, Wang Z, Liang C, Richard S. Arginine methylation of SARS-Cov-2 nucleocapsid protein regulates RNA binding, its ability to suppress stress granule formation, and viral replication. J Biol Chem 2021; 297:100821. [PMID: 34029587 PMCID: PMC8141346 DOI: 10.1016/j.jbc.2021.100821] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/13/2021] [Accepted: 05/20/2021] [Indexed: 12/18/2022] Open
Abstract
Viral proteins are known to be methylated by host protein arginine methyltransferases (PRMTs) necessary for the viral life cycle, but it remains unknown whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) proteins are methylated. Herein, we show that PRMT1 methylates SARS-CoV-2 nucleocapsid (N) protein at residues R95 and R177 within RGG/RG motifs, preferred PRMT target sequences. We confirmed arginine methylation of N protein by immunoblotting viral proteins extracted from SARS-CoV-2 virions isolated from cell culture. Type I PRMT inhibitor (MS023) or substitution of R95 or R177 with lysine inhibited interaction of N protein with the 5'-UTR of SARS-CoV-2 genomic RNA, a property required for viral packaging. We also defined the N protein interactome in HEK293 cells, which identified PRMT1 and many of its RGG/RG substrates, including the known interacting protein G3BP1 as well as other components of stress granules (SGs), which are part of the host antiviral response. Methylation of R95 regulated the ability of N protein to suppress the formation of SGs, as R95K substitution or MS023 treatment blocked N-mediated suppression of SGs. Also, the coexpression of methylarginine reader Tudor domain-containing protein 3 quenched N protein-mediated suppression of SGs in a dose-dependent manner. Finally, pretreatment of VeroE6 cells with MS023 significantly reduced SARS-CoV-2 replication. Because type I PRMT inhibitors are already undergoing clinical trials for cancer treatment, inhibiting arginine methylation to target the later stages of the viral life cycle such as viral genome packaging and assembly of virions may represent an additional therapeutic application of these drugs.
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Affiliation(s)
- Ting Cai
- Segal Cancer Center, Lady Davis Institute for Medical Research and Gerald Bronfman Department of Oncology and Departments of Biochemistry, Human Genetics and Medicine, McGill University, Montréal, Québec, Canada
| | - Zhenbao Yu
- Segal Cancer Center, Lady Davis Institute for Medical Research and Gerald Bronfman Department of Oncology and Departments of Biochemistry, Human Genetics and Medicine, McGill University, Montréal, Québec, Canada
| | - Zhen Wang
- McGill Centre for Viral Diseases, Lady Davis Institute for Medical Research and Department of Medicine, Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
| | - Chen Liang
- McGill Centre for Viral Diseases, Lady Davis Institute for Medical Research and Department of Medicine, Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
| | - Stéphane Richard
- Segal Cancer Center, Lady Davis Institute for Medical Research and Gerald Bronfman Department of Oncology and Departments of Biochemistry, Human Genetics and Medicine, McGill University, Montréal, Québec, Canada.
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19
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Abstract
The specific interaction of importins with nuclear localization signals (NLSs) of cargo proteins not only mediates nuclear import but also, prevents their aberrant phase separation and stress granule recruitment in the cytoplasm. The importin Transportin-1 (TNPO1) plays a key role in the (patho-)physiology of both processes. Here, we report that both TNPO1 and Transportin-3 (TNPO3) recognize two nonclassical NLSs within the cold-inducible RNA-binding protein (CIRBP). Our biophysical investigations show that TNPO1 recognizes an arginine-glycine(-glycine) (RG/RGG)-rich region, whereas TNPO3 recognizes a region rich in arginine-serine-tyrosine (RSY) residues. These interactions regulate nuclear localization, phase separation, and stress granule recruitment of CIRBP in cells. The presence of both RG/RGG and RSY regions in numerous other RNA-binding proteins suggests that the interaction of TNPO1 and TNPO3 with these nonclassical NLSs may regulate the formation of membraneless organelles and subcellular localization of numerous proteins.
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20
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An ortholog of the Vasa intronic gene is required for small RNA-mediated translation repression in Chlamydomonas reinhardtii. Proc Natl Acad Sci U S A 2019; 117:761-770. [PMID: 31871206 PMCID: PMC6955306 DOI: 10.1073/pnas.1908356117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Small RNAs (sRNAs) are a class of noncoding RNAs that regulate complementary mRNAs, by triggering translation repression and/or transcript decay, and influence multiple biological processes. In animals, land plants, and some protists like the alga Chlamydomonas, sRNAs can repress translation of polyribosome-associated mRNAs, without or with only minimal transcript destabilization. However, the precise silencing mechanism is poorly understood. We found that Chlamydomonas VIG1, a homolog of the Drosophila melanogaster Vasa intronic gene and a member of a widely conserved protein family in eukaryotes, is involved in this process. VIG1 appears to be an ancillary ribosomal constituent. Additionally, VIG1 copurifies with core components of sRNA effector complexes and plays a key role in the sRNA-mediated translation repression of polyribosomal transcripts. Small RNAs (sRNAs) associate with Argonaute (AGO) proteins in effector complexes, termed RNA-induced silencing complexes (RISCs), which regulate complementary transcripts by translation inhibition and/or RNA degradation. In the unicellular alga Chlamydomonas, several metazoans, and land plants, emerging evidence indicates that polyribosome-associated transcripts can be translationally repressed by RISCs without substantial messenger RNA (mRNA) destabilization. However, the mechanism of translation inhibition in a polyribosomal context is not understood. Here we show that Chlamydomonas VIG1, an ortholog of the Drosophila melanogaster Vasa intronic gene (VIG), is required for this process. VIG1 localizes predominantly in the cytosol and comigrates with monoribosomes and polyribosomes by sucrose density gradient sedimentation. A VIG1-deleted mutant shows hypersensitivity to the translation elongation inhibitor cycloheximide, suggesting that VIG1 may have a nonessential role in ribosome function/structure. Additionally, FLAG-tagged VIG1 copurifies with AGO3 and Dicer-like 3 (DCL3), consistent with it also being a component of the RISC. Indeed, VIG1 is necessary for the repression of sRNA-targeted transcripts at the translational level but is dispensable for cleavage-mediated RNA interference and for the association of the AGO3 effector with polyribosomes or target transcripts. Our results suggest that VIG1 is an ancillary ribosomal component and plays a role in sRNA-mediated translation repression of polyribosomal transcripts.
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21
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Colleti C, Melo-Hanchuk TD, da Silva FRM, Saito Â, Kobarg J. Complex interactomes and post-translational modifications of the regulatory proteins HABP4 and SERBP1 suggest pleiotropic cellular functions. World J Biol Chem 2019; 10:44-64. [PMID: 31768228 PMCID: PMC6872977 DOI: 10.4331/wjbc.v10.i3.44] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 08/30/2019] [Accepted: 10/15/2019] [Indexed: 02/05/2023] Open
Abstract
The 57 kDa antigen recognized by the Ki-1 antibody, is also known as intracellular hyaluronic acid binding protein 4 and shares 40.7% identity and 67.4% similarity with serpin mRNA binding protein 1, which is also named CGI-55, or plasminogen activator inhibitor type-1-RNA binding protein-1, indicating that they might be paralog proteins, possibly with similar or redundant functions in human cells. Through the identification of their protein interactomes, both regulatory proteins have been functionally implicated in transcriptional regulation, mRNA metabolism, specifically RNA splicing, the regulation of mRNA stability, especially, in the context of the progesterone hormone response, and the DNA damage response. Both proteins also show a complex pattern of post-translational modifications, involving Ser/Thr phosphorylation, mainly through protein kinase C, arginine methylation and SUMOylation, suggesting that their functions and locations are highly regulated. Furthermore, they show a highly dynamic cellular localization pattern with localizations in both the cytoplasm and nucleus as well as punctuated localizations in both granular cytoplasmic protein bodies, upon stress, and nuclear splicing speckles. Several reports in the literature show altered expressions of both regulatory proteins in a series of cancers as well as mutations in their genes that may contribute to tumorigenesis. This review highlights important aspects of the structure, interactome, post-translational modifications, sub-cellular localization and function of both regulatory proteins and further discusses their possible functions and their potential as tumor markers in different cancer settings.
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Affiliation(s)
- Carolina Colleti
- Faculty of Pharmaceutical Sciences, University of Campinas, Campinas 13083-871, Brazil
- Institute of Biology, Departament of Biochemistry and Tissue Biology, University of Campinas, Campinas 13083-862, Brazil
| | - Talita Diniz Melo-Hanchuk
- Institute of Biology, Departament of Biochemistry and Tissue Biology, University of Campinas, Campinas 13083-862, Brazil
| | - Flávia Regina Moraes da Silva
- Faculty of Pharmaceutical Sciences, University of Campinas, Campinas 13083-871, Brazil
- Institute of Biology, Departament of Biochemistry and Tissue Biology, University of Campinas, Campinas 13083-862, Brazil
| | - Ângela Saito
- Laboratório Nacional de Biociências, CNPEM, Campinas 13083-970, Brazil
| | - Jörg Kobarg
- Faculty of Pharmaceutical Sciences, University of Campinas, Campinas 13083-871, Brazil
- Institute of Biology, Departament of Biochemistry and Tissue Biology, University of Campinas, Campinas 13083-862, Brazil
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22
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Downregulation of PRMT1 promotes the senescence and migration of a non-MYCN amplified neuroblastoma SK-N-SH cells. Sci Rep 2019; 9:1771. [PMID: 30741995 PMCID: PMC6370813 DOI: 10.1038/s41598-018-38394-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 12/20/2018] [Indexed: 11/09/2022] Open
Abstract
Protein arginine methyltransferase 1 (PRMT1) catalyzing the formation of asymmetric dimethylarginines has been implicated in cancer development, metastasis, and prognosis. In this study, we investigated the effects of low PRMT1 levels on a non-MYCN amplified neuroblastoma SK-N-SH cell line. Stable PRMT1-knockdown (PRMT1-KD) cells showed reduced growth rates and cell cycle arrest at G2/M. They also exhibited senescent phenotypes and increased p53 expression. p21 and PAI-1, which are two p53 downstream targets critical for senescence, were significantly induced in SK-N-SH cells subjected to either PRMT1-KD or inhibitor treatment. The induction was suppressed by a p53 inhibitor and marginal in a p53-null SK-N-AS cell line, suggesting dependence on p53. In general, the DNA damage and ROS levels of the PRMT1-KD SK-N-SH cells were slightly increased. Their migration activity also increased with the induction of PAI-1. Thus, PRMT1 downregulation released the repression of cellular senescence and migration activity in SK-N-SH cells. These results might partially explain the poor prognostic outcome of low PRMT1 in a non-MYCN-amplified cohort and indicate the multifaceted complexity of PRMT1 as a biological regulator of neuroblastoma.
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23
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Hofweber M, Dormann D. Friend or foe-Post-translational modifications as regulators of phase separation and RNP granule dynamics. J Biol Chem 2018; 294:7137-7150. [PMID: 30587571 DOI: 10.1074/jbc.tm118.001189] [Citation(s) in RCA: 227] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Ribonucleoprotein (RNP) granules are membrane-less organelles consisting of RNA-binding proteins (RBPs) and RNA. RNA granules form through liquid-liquid phase separation (LLPS), whereby weak promiscuous interactions among RBPs and/or RNAs create a dense network of interacting macromolecules and drive the phase separation. Post-translational modifications (PTMs) of RBPs have emerged as important regulators of LLPS and RNP granule dynamics, as they can directly weaken or enhance the multivalent interactions between phase-separating macromolecules or can recruit or exclude certain macromolecules into or from condensates. Here, we review recent insights into how PTMs regulate phase separation and RNP granule dynamics, in particular arginine (Arg)-methylation and phosphorylation. We discuss how these PTMs regulate the phase behavior of prototypical RBPs and how, as "friend or foe," they might influence the assembly, disassembly, or material properties of cellular RNP granules, such as stress granules or amyloid-like condensates. We particularly highlight how PTMs control the phase separation and aggregation behavior of disease-linked RBPs. We also review how disruptions of PTMs might be involved in aberrant phase transitions and the formation of amyloid-like protein aggregates as observed in neurodegenerative diseases.
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Affiliation(s)
- Mario Hofweber
- From the BioMedical Center, Cell Biology, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 9, 82152 Planegg-Martinsried.,the Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, and
| | - Dorothee Dormann
- From the BioMedical Center, Cell Biology, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 9, 82152 Planegg-Martinsried, .,the Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, and.,the Munich Cluster for Systems Neurology (SyNergy), Feodor-Lynen-Strasse 17, 81377 Munich, Germany
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24
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Muto A, Sugihara Y, Shibakawa M, Oshima K, Matsuda T, Nadano D. The mRNA-binding protein Serbp1 as an auxiliary protein associated with mammalian cytoplasmic ribosomes. Cell Biochem Funct 2018; 36:312-322. [PMID: 30039520 DOI: 10.1002/cbf.3350] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 04/23/2018] [Accepted: 06/26/2018] [Indexed: 01/27/2023]
Abstract
While transcription plays an obviously important role in gene expression, translation has recently been emerged as a key step that defines the composition and quality of the proteome in the cell of higher eukaryotes including mammals. Selective translation is supposed to be regulated by the structural heterogeneity of cytoplasmic ribosomes including differences in protein composition and chemical modifications. However, the current knowledge on the heterogeneity of mammalian ribosomes is limited. Here, we report mammalian Serbp1 as a ribosome-associated protein. The translated products of Serbp1 gene, including the longest isoform, were found to be localized in the nucleolus as well as in the cytoplasm. Subcellular fractionation indicated that most of cytoplasmic Serbp1 molecules were precipitated by ultracentrifugation. Proteomic analysis identified Serbp1 in the cytoplasmic ribosomes of the rodent testis. Polysome profiling suggested that Serbp1, as a component of the small 40S subunit, was included in translating ribosomes (polysomes). Cosedimentation of Serbp1 with the 40S subunit was observed after dissociation of the ribosomal subunits. Serbp1 was also included in the ribosomes of human cancer cells, which may lead to a mechanistic understanding of an emerging link between Serbp1 and tumour progression. SIGNIFICANCE OF THE STUDY In mammalian cells, the final protein output of their genetic program is determined not only by controlling transcription but also by regulating the posttranscriptional events. Although mRNA-binding proteins and the cytoplasmic ribosome have long been recognized as central players in the posttranscriptional regulation, their physical and functional interactions are still far from a complete understanding. Here, we describe the intracellular localization of Serbp1, an mRNA-binding protein, and the inclusion of this protein in actively translating ribosomes in normal and cancer cells. These findings shed a new light into molecular mechanisms underlying Serbp1 action in translational gene regulation and tumour progression.
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Affiliation(s)
- Akiko Muto
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Yoshihiko Sugihara
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Minami Shibakawa
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Kenzi Oshima
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Tsukasa Matsuda
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Daita Nadano
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
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25
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Benhalevy D, Gupta SK, Danan CH, Ghosal S, Sun HW, Kazemier HG, Paeschke K, Hafner M, Juranek SA. The Human CCHC-type Zinc Finger Nucleic Acid-Binding Protein Binds G-Rich Elements in Target mRNA Coding Sequences and Promotes Translation. Cell Rep 2017; 18:2979-2990. [PMID: 28329689 DOI: 10.1016/j.celrep.2017.02.080] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 07/18/2016] [Accepted: 02/27/2017] [Indexed: 12/16/2022] Open
Abstract
The CCHC-type zinc finger nucleic acid-binding protein (CNBP/ZNF9) is conserved in eukaryotes and is essential for embryonic development in mammals. It has been implicated in transcriptional, as well as post-transcriptional, gene regulation; however, its nucleic acid ligands and molecular function remain elusive. Here, we use multiple systems-wide approaches to identify CNBP targets and function. We used photoactivatable ribonucleoside-enhanced crosslinking and immunoprecipitation (PAR-CLIP) to identify 8,420 CNBP binding sites on 4,178 mRNAs. CNBP preferentially bound G-rich elements in the target mRNA coding sequences, most of which were previously found to form G-quadruplex and other stable structures in vitro. Functional analyses, including RNA sequencing, ribosome profiling, and quantitative mass spectrometry, revealed that CNBP binding did not influence target mRNA abundance but rather increased their translational efficiency. Considering that CNBP binding prevented G-quadruplex structure formation in vitro, we hypothesize that CNBP is supporting translation by resolving stable structures on mRNAs.
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Affiliation(s)
- Daniel Benhalevy
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD 20892, USA
| | - Sanjay K Gupta
- Department of Biochemistry, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Charles H Danan
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD 20892, USA
| | - Suman Ghosal
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD 20892, USA
| | - Hong-Wei Sun
- Biostatistics and Datamining Section, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hinke G Kazemier
- European Research Institute for the Biology of Ageing (ERIBA), University Medical Center Groningen, University of Groningen, 9713 AV Groningen, the Netherlands
| | - Katrin Paeschke
- European Research Institute for the Biology of Ageing (ERIBA), University Medical Center Groningen, University of Groningen, 9713 AV Groningen, the Netherlands
| | - Markus Hafner
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD 20892, USA.
| | - Stefan A Juranek
- Department of Biochemistry, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany; European Research Institute for the Biology of Ageing (ERIBA), University Medical Center Groningen, University of Groningen, 9713 AV Groningen, the Netherlands.
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26
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Wang YC, Wang CW, Lin WC, Tsai YJ, Chang CP, Lee YJ, Lin MJ, Li C. Identification, chromosomal arrangements and expression analyses of the evolutionarily conserved prmt1 gene in chicken in comparison with its vertebrate paralogue prmt8. PLoS One 2017; 12:e0185042. [PMID: 28934323 PMCID: PMC5608299 DOI: 10.1371/journal.pone.0185042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 09/04/2017] [Indexed: 01/22/2023] Open
Abstract
Nine protein arginine methyltransferases (PRMTs) are conserved in mammals and fish. Among these, PRMT1 is the major type I PRMT for asymmetric dimethylarginine (ADMA) formation and is the most conserved and widely distributed one. Two chicken prmt1 splicing variants were assembled and confirmed by RT-PCR experiments. However, only two scaffolds containing single separate prmt1 exon with high GC contents are present in the current chicken genome assembly. Besides, prmt1 exons are scattered in separate small scaffolds in most avian species. Complete prmt1 gene has only been predicted from two falcon species with few neighboring genes. Crocodilians are considered close to the common ancestor shared by crocodilians and birds. The gene arrangements around prmt1 in American alligator are different from that in birds but are largely conserved in human. Orthologues of genes in a large segment of human chromosomal 19 around PRMT1 are missing or not assigned to the current chicken chromosomes. In comparison, prmt8, the prmt1 paralogue, is on chicken chromosome 1 with the gene arrangements downstream of prmt8 highly conserved in birds, crocodilians, and human. However, the ones upstream vary greatly in birds. Biochemically, we found that though prmt1 transcripts were detected, limited or none PRMT1 protein was present in chicken tissues. Moreover, a much higher level of PRMT8 protein was detected in chicken brain than in mouse brain. While PRMT8 is brain specific in other vertebrate species studied, low level of PRMT8 was present in chicken but not mouse liver and muscle. We also showed that the ADMA level in chicken was similar to that in mouse. This study provides the critical information of chicken PRMT1 and PRMT8 for future analyses of the function of protein arginine methyltransferases in birds.
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Affiliation(s)
- Yi-Chun Wang
- Department of Biomedical Sciences, Chung Shan Medical University, Taichung, Taiwan
- Department of Medical Research, Chung Shan Medical University Hospital, Taichung, Taiwan, ROC
| | - Chien-Wen Wang
- Department of Biomedical Sciences, Chung Shan Medical University, Taichung, Taiwan
| | - Wen-Chang Lin
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, ROC
| | - Yun-Jung Tsai
- Department of Biomedical Sciences, Chung Shan Medical University, Taichung, Taiwan
| | - Chien-Ping Chang
- Department of Biomedical Sciences, Chung Shan Medical University, Taichung, Taiwan
| | - Yu-Jen Lee
- Department of Biomedical Sciences, Chung Shan Medical University, Taichung, Taiwan
| | - Min-Jon Lin
- Department of Biomedical Sciences, Chung Shan Medical University, Taichung, Taiwan
- Department of Medical Research, Chung Shan Medical University Hospital, Taichung, Taiwan, ROC
| | - Chuan Li
- Department of Biomedical Sciences, Chung Shan Medical University, Taichung, Taiwan
- Department of Medical Research, Chung Shan Medical University Hospital, Taichung, Taiwan, ROC
- * E-mail:
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27
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Saito Â, Souza EE, Costa FC, Meirelles GV, Gonçalves KA, Santos MT, Bressan GC, McComb ME, Costello CE, Whelan SA, Kobarg J. Human Regulatory Protein Ki-1/57 Is a Target of SUMOylation and Affects PML Nuclear Body Formation. J Proteome Res 2017; 16:3147-3157. [PMID: 28695742 DOI: 10.1021/acs.jproteome.7b00001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Ki-1/57 is a nuclear and cytoplasmic regulatory protein first identified in malignant cells from Hodgkin's lymphoma. It is involved in gene expression regulation on both transcriptional and mRNA metabolism levels. Ki-1/57 belongs to the family of intrinsically unstructured proteins and undergoes phosphorylation by PKC and methylation by PRMT1. Previous characterization of its protein interaction profile by yeast two-hybrid screening showed that Ki-1/57 interacts with proteins of the SUMOylation machinery, the SUMO E2 conjugating enzyme UBC9 and the SUMO E3 ligase PIAS3, which suggested that Ki-1/57 could be involved with this process. Here we identified seven potential SUMO target sites (lysine residues) on Ki-1/57 sequence and observed that Ki-1/57 is modified by SUMO proteins in vitro and in vivo. We showed that SUMOylation of Ki-1/57 occurred on lysines 213, 276, and 336. In transfected cells expressing FLAG-Ki-1/57 wild-type, its paralog FLAG-CGI-55 wild-type, or their non-SUMOylated triple mutants, the number of PML-nuclear bodies (PML-NBs) is reduced compared with the control cells not expressing the constructs. More interestingly, after treating cells with arsenic trioxide (As2O3), the number of PML-NBs is no longer reduced when the non-SUMOylated triple mutant Ki-1/57 is expressed, suggesting that the SUMOylation of Ki-1/57 has a role in the control of As2O3-induced PML-NB formation. A proteome-wide analysis of Ki-1/57 partners in the presence of either SUMO-1 or SUMO-2 suggests that the involvement of Ki-1/57 with the regulation of gene expression is independent of the presence of either SUMO-1 or SUMO-2; however, the presence of SUMO-1 strongly influences the interaction of Ki-1/57 with proteins associated with cellular metabolism, maintenance, and cell cycle.
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Affiliation(s)
- Ângela Saito
- Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM) , Campinas, São Paulo 13083-970, Brazil
| | - Edmarcia E Souza
- Faculdade de Ciências Farmacêuticas, Universidade Estadual de Campinas , Campinas, São Paulo 13083-859, Brazil
| | - Fernanda C Costa
- Instituto de Física de São Carlos, Universidade de São Paulo , São Carlos, São Paulo 13563-120, Brazil
| | - Gabriela V Meirelles
- Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM) , Campinas, São Paulo 13083-970, Brazil
| | - Kaliandra A Gonçalves
- Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM) , Campinas, São Paulo 13083-970, Brazil
| | - Marcos T Santos
- ONKOS Molecular Diagnostics, Inc. , R&D Department, Ribeirão Preto, São Paulo 14056-680, Brazil
| | - Gustavo C Bressan
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa (UFV) , Viçosa, Minas Gerais 36570-000, Brazil
| | - Mark E McComb
- Center for Biomedical Mass Spectrometry, Boston University School of Medicine , Boston, Massachusetts 02118, United States
| | - Catherine E Costello
- Center for Biomedical Mass Spectrometry, Boston University School of Medicine , Boston, Massachusetts 02118, United States
| | - Stephen A Whelan
- Center for Biomedical Mass Spectrometry, Boston University School of Medicine , Boston, Massachusetts 02118, United States
| | - Jörg Kobarg
- Faculdade de Ciências Farmacêuticas, Universidade Estadual de Campinas , Campinas, São Paulo 13083-859, Brazil.,Departamento de Bioquímica e Biologia Tecidual, Programa de Pós-graduação em Biologia Funcional e Molecular, Universidade Estadual de Campinas , Campinas, São Paulo 13083-862, Brazil
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28
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Bolger GB. The RNA-binding protein SERBP1 interacts selectively with the signaling protein RACK1. Cell Signal 2017; 35:256-263. [PMID: 28267599 DOI: 10.1016/j.cellsig.2017.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 02/23/2017] [Accepted: 03/02/2017] [Indexed: 12/19/2022]
Abstract
The RACK1 protein interacts with numerous proteins involved in signal transduction, the cytoskeleton, and mRNA splicing and translation. We used the 2-hybrid system to identify additional proteins interacting with RACK1 and isolated the RNA-binding protein SERBP1. SERPB1 shares amino acid sequence homology with HABP4 (also known as Ki-1/57), a component of the RNA spicing machinery that has been shown previously to interact with RACK1. Several different isoforms of SERBP1, generated by alternative mRNA splicing, interacted with RACK1 with indistinguishable interaction strength, as determined by a 2-hybrid beta-galactosidase assay. Analysis of deletion constructs of SERBP1 showed that the C-terminal third of the SERBP1 protein, which contains one of its two substrate sites for protein arginine N-methyltransferase 1 (PRMT1), is necessary and sufficient for it to interact with RACK1. Analysis of single amino acid substitutions in RACK1, identified in a reverse 2-hybrid screen, showed very substantial overlap with those implicated in the interaction of RACK1 with the cAMP-selective phosphodiesterase PDE4D5. These data are consistent with SERBP1 interacting selectively with RACK1, mediated by an extensive interaction surface on both proteins.
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Affiliation(s)
- Graeme B Bolger
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294-3300, USA; Department of Pharmacology, University of Alabama at Birmingham, Birmingham, AL 35294-3300, USA.
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29
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Mari Y, West GM, Scharager-Tapia C, Pascal BD, Garcia-Ordonez RD, Griffin PR. SERBP1 Is a Component of the Liver Receptor Homologue-1 Transcriptional Complex. J Proteome Res 2015; 14:4571-80. [PMID: 26398198 DOI: 10.1021/acs.jproteome.5b00379] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Liver receptor homologue-1 (LRH1) is an orphan nuclear receptor that has been shown to play a role in the transcriptional regulation of pathways involved in cancer. Elucidating the components of the LRH1 transcriptional complex to better understand endogenous regulation of the receptor as well as its role in cancer remains a high priority. A sub-cellular enrichment strategy coupled with proteomic approaches was employed to identify putative LRH1 co-regulators. Nuclear fractionation protocol was essential for detection of LRH1 peptides by mass spectrometry (MS), with most peptides being observed in the insoluble fraction (receptor bound to DNA). SERBP1 and ILF3 were identified as LRH1 interacting partners by both Western blot and MS/MS analysis. Receptor knockdown by siRNA showed an increase in SERBP1 expression, while ILF3 expression was unchanged. In contrast, receptor overexpression decreased only SERBP1 mRNA levels. Consistent with these data, in a promoter:reporter assay, binding of LRH1 to the promoter region of SERBP1 resulted in a decrease in the expression level of the reporter gene, subsequently inhibiting transcription. Given the receptor's role in cancer progression, the study here elucidates additional transcriptional machinery involved in LRH1 signaling and potentially provides new targets for therapeutics development.
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Affiliation(s)
- Yelenis Mari
- Department of Molecular Therapeutics, ‡Mass Spectrometry & Proteomics Core, and §Informatics Core, The Scripps Research Institute , Jupiter, Florida 33458, United States
| | - Graham M West
- Department of Molecular Therapeutics, ‡Mass Spectrometry & Proteomics Core, and §Informatics Core, The Scripps Research Institute , Jupiter, Florida 33458, United States
| | - Catherina Scharager-Tapia
- Department of Molecular Therapeutics, ‡Mass Spectrometry & Proteomics Core, and §Informatics Core, The Scripps Research Institute , Jupiter, Florida 33458, United States
| | - Bruce D Pascal
- Department of Molecular Therapeutics, ‡Mass Spectrometry & Proteomics Core, and §Informatics Core, The Scripps Research Institute , Jupiter, Florida 33458, United States
| | - Ruben D Garcia-Ordonez
- Department of Molecular Therapeutics, ‡Mass Spectrometry & Proteomics Core, and §Informatics Core, The Scripps Research Institute , Jupiter, Florida 33458, United States
| | - Patrick R Griffin
- Department of Molecular Therapeutics, ‡Mass Spectrometry & Proteomics Core, and §Informatics Core, The Scripps Research Institute , Jupiter, Florida 33458, United States
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30
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Costa FC, Saito A, Gonçalves KA, Vidigal PM, Meirelles GV, Bressan GC, Kobarg J. Ki-1/57 and CGI-55 ectopic expression impact cellular pathways involved in proliferation and stress response regulation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2944-56. [PMID: 25205453 DOI: 10.1016/j.bbamcr.2014.08.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 08/27/2014] [Accepted: 08/28/2014] [Indexed: 10/24/2022]
Abstract
Ki-1/57 (HABP4) and CGI-55 (SERBP1) are regulatory proteins and paralogs with 40.7% amino acid sequence identity and 67.4% similarity. Functionally, they have been implicated in the regulation of gene expression on both the transcriptional and mRNA metabolism levels. A link with tumorigenesis is suggested, since both paralogs show altered expression levels in tumor cells and the Ki-1/57 gene is found in a region of chromosome 9q that represents a haplotype for familiar colon cancer. However, the target genes regulated by Ki-1/57 and CGI-55 are unknown. Here, we analyzed the alterations of the global transcriptome profile after Ki-1/57 or CGI-55 overexpression in HEK293T cells by DNA microchip technology. We were able to identify 363 or 190 down-regulated and 50 or 27 up-regulated genes for Ki-1/57 and CGI-55, respectively, of which 20 were shared between both proteins. Expression levels of selected genes were confirmed by qRT-PCR both after protein overexpression and siRNA knockdown. The majority of the genes with altered expression were associated to proliferation, apoptosis and cell cycle control processes, prompting us to further explore these contexts experimentally. We observed that overexpression of Ki-1/57 or CGI-55 results in reduced cell proliferation, mainly due to a G1 phase arrest, whereas siRNA knockdown of CGI-55 caused an increase in proliferation. In the case of Ki-1/57 overexpression, we found protection from apoptosis after treatment with the ER-stress inducer thapsigargin. Together, our data give important new insights that may help to explain these proteins putative involvement in tumorigenic events.
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Affiliation(s)
- Fernanda C Costa
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo, Brasil.
| | - Angela Saito
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo, Brasil; Departamento de Bioquímica-Programa de Pós-graduação em Biologia Funcional e Molecular, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brasil.
| | - Kaliandra A Gonçalves
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo, Brasil; Departamento de Bioquímica-Programa de Pós-graduação em Biologia Funcional e Molecular, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brasil.
| | - Pedro M Vidigal
- Laboratório de Bioinformática, Instituto de Biotecnologia Aplicada à Agropecuária-BIOAGRO, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brasil.
| | - Gabriela V Meirelles
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo, Brasil.
| | - Gustavo C Bressan
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo, Brasil; Departamento de Bioquímica-Programa de Pós-graduação em Biologia Funcional e Molecular, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brasil.
| | - Jörg Kobarg
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo, Brasil; Departamento de Bioquímica-Programa de Pós-graduação em Biologia Funcional e Molecular, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brasil; Departamento de Genética, Evolução e Bioagentes - Programa de Pós-graduação em Genética e Biologia Molecular, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brasil.
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31
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Wei HM, Hu HH, Chang GY, Lee YJ, Li YC, Chang HH, Li C. Arginine methylation of the cellular nucleic acid binding protein does not affect its subcellular localization but impedes RNA binding. FEBS Lett 2014; 588:1542-8. [DOI: 10.1016/j.febslet.2014.03.052] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/26/2014] [Accepted: 03/27/2014] [Indexed: 10/25/2022]
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32
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Lee YJ, Wei HM, Chen LY, Li C. Localization of SERBP1 in stress granules and nucleoli. FEBS J 2013; 281:352-64. [DOI: 10.1111/febs.12606] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 11/06/2013] [Indexed: 12/24/2022]
Affiliation(s)
- Yu-Jen Lee
- Institute of Biochemistry and Biotechnology; Chung Shan Medical University; Taichung Taiwan
| | - Hung-Ming Wei
- Department of Biomedical Sciences; Chung Shan Medical University; Taichung Taiwan
| | - Ling-Yun Chen
- Institute of Biochemistry and Biotechnology; Chung Shan Medical University; Taichung Taiwan
| | - Chuan Li
- Department of Biomedical Sciences; Chung Shan Medical University; Taichung Taiwan
- Department of Medical Research; Chung Shan Medical University Hospital; Taichung Taiwan
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33
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Abstract
Motifs rich in arginines and glycines were recognized several decades ago to play functional roles and were termed glycine-arginine-rich (GAR) domains and/or RGG boxes. We review here the evolving functions of the RGG box along with several sequence variations that we collectively term the RGG/RG motif. Greater than 1,000 human proteins harbor the RGG/RG motif, and these proteins influence numerous physiological processes such as transcription, pre-mRNA splicing, DNA damage signaling, mRNA translation, and the regulation of apoptosis. In particular, we discuss the role of the RGG/RG motif in mediating nucleic acid and protein interactions, a function that is often regulated by arginine methylation and partner-binding proteins. The physiological relevance of the RGG/RG motif is highlighted by its association with several diseases including neurological and neuromuscular diseases and cancer. Herein, we discuss the evidence for the emerging diverse functionality of this important motif.
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Affiliation(s)
- Palaniraja Thandapani
- Terry Fox Molecular Oncology Group and Bloomfield Center for Research on Aging, Lady Davis Institute for Medical Research and Departments of Oncology and Medicine, McGill University, Montreal, Quebec H3T 1E2, Canada
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34
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Chew TG, Peaston A, Lim AK, Lorthongpanich C, Knowles BB, Solter D. A tudor domain protein SPINDLIN1 interacts with the mRNA-binding protein SERBP1 and is involved in mouse oocyte meiotic resumption. PLoS One 2013; 8:e69764. [PMID: 23894536 PMCID: PMC3718791 DOI: 10.1371/journal.pone.0069764] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Accepted: 06/12/2013] [Indexed: 12/11/2022] Open
Abstract
Mammalian oocytes are arrested at prophase I of meiosis, and resume meiosis prior to ovulation. Coordination of meiotic arrest and resumption is partly dependent on the post-transcriptional regulation of maternal transcripts. Here, we report that, SPINDLIN1 (SPIN1), a maternal protein containing Tudor-like domains, interacts with a known mRNA-binding protein SERBP1, and is involved in regulating maternal transcripts to control meiotic resumption. Mouse oocytes deficient for Spin1 undergo normal folliculogenesis, but are defective in resuming meiosis. SPIN1, via its Tudor-like domain, forms a ribonucleoprotein complex with SERBP1, and regulating mRNA stability and/or translation. The mRNA for the cAMP-degrading enzyme, PDE3A, is reduced in Spin1 mutant oocytes, possibly contributing to meiotic arrest. Our study demonstrates that Spin1 regulates maternal transcripts post-transcriptionally and is involved in meiotic resumption.
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Affiliation(s)
- Ting Gang Chew
- Mammalian Development Laboratory, Institute of Medical Biology, A-STAR, Singapore, Singapore.
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Proteomic analyses and identification of arginine methylated proteins differentially recognized by autosera from anti-Sm positive SLE patients. J Biomed Sci 2013; 20:27. [PMID: 23642268 PMCID: PMC3663782 DOI: 10.1186/1423-0127-20-27] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 04/25/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Antibodies against spliceosome Sm proteins (anti-Sm autoantibodies) are specific to the autoimmune disease systemic lupus erythematosus (SLE). Anti-Sm autosera have been reported to specifically recognize Sm D1 and D3 with symmetric di-methylarginines (sDMA). We investigated if anti-Sm sera from local SLE patients can differentially recognize Sm proteins or any other proteins due to their methylation states. RESULTS We prepared HeLa cell proteins at normal or hypomethylation states (treated with an indirect methyltransferase inhibitor adenosine dialdehyde, AdOx). A few signals detected by the anti-Sm positive sera from typical SLE patients decreased consistently in the immunoblots of hypomethylated cell extracts. The differentially detected signals by one serum (Sm1) were pinpointed by two-dimensional electrophoresis and identified by mass spectrometry. Three identified proteins: splicing factor, proline- and glutamine-rich (SFPQ), heterogeneous nuclear ribonucleoprotein D-like (hnRNP DL) and cellular nucleic acid binding protein (CNBP) are known to contain methylarginines in their glycine and arginine rich (GAR) sequences. We showed that recombinant hnRNP DL and CNBP expressed in Escherichia coli can be detected by all anti-Sm positive sera we tested. As CNBP appeared to be differentially detected by the SLE sera in the pilot study, differential recognition of arginine methylated CNBP protein by the anti-Sm positive sera were further examined. Hypomethylated FLAG-CNBP protein immunopurified from AdOx-treated HeLa cells was less recognized by Sm1 compared to the CNBP protein expressed in untreated cells. Two of 20 other anti-Sm positive sera specifically differentiated the FLAG-CNBP protein expressed in HeLa cells due to the methylation. We also observed deferential recognition of methylated recombinant CNBP proteins expressed from E. coli by some of the autosera. CONCLUSION Our study showed that hnRNP DL and CNBP are novel antigens for SLE patients and the recognition of CNBP might be differentiated dependent on the level of arginine methylation.
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Serce NB, Boesl A, Klaman I, von Serényi S, Noetzel E, Press MF, Dimmler A, Hartmann A, Sehouli J, Knuechel R, Beckmann MW, Fasching PA, Dahl E. Overexpression of SERBP1 (Plasminogen activator inhibitor 1 RNA binding protein) in human breast cancer is correlated with favourable prognosis. BMC Cancer 2012; 12:597. [PMID: 23236990 PMCID: PMC3538721 DOI: 10.1186/1471-2407-12-597] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Accepted: 12/06/2012] [Indexed: 11/17/2022] Open
Abstract
Background Plasminogen activator inhibitor 1 (PAI-1) overexpression is an important prognostic and predictive biomarker in human breast cancer. SERBP1, a protein that is supposed to regulate the stability of PAI-1 mRNA, may play a role in gynaecological cancers as well, since upregulation of SERBP1 was described in ovarian cancer recently. This is the first study to present a systematic characterisation of SERBP1 expression in human breast cancer and normal breast tissue at both the mRNA and the protein level. Methods Using semiquantitative realtime PCR we analysed SERBP1 expression in different normal human tissues (n = 25), and in matched pairs of normal (n = 7) and cancerous breast tissues (n = 7). SERBP1 protein expression was analysed in two independent cohorts on tissue microarrays (TMAs), an initial evaluation set, consisting of 193 breast carcinomas and 48 normal breast tissues, and a second large validation set, consisting of 605 breast carcinomas. In addition, a collection of benign (n = 2) and malignant (n = 6) mammary cell lines as well as breast carcinoma lysates (n = 16) were investigated for SERBP1 expression by Western blot analysis. Furthermore, applying non-radioisotopic in situ hybridisation a subset of normal (n = 10) and cancerous (n = 10) breast tissue specimens from the initial TMA were analysed for SERBP1 mRNA expression. Results SERBP1 is not differentially expressed in breast carcinoma compared to normal breast tissue, both at the RNA and protein level. However, recurrence-free survival analysis showed a significant correlation (P = 0.008) between abundant SERBP1 expression in breast carcinoma and favourable prognosis. Interestingly, overall survival analysis also displayed a tendency (P = 0.09) towards favourable prognosis when SERBP1 was overexpressed in breast cancer. Conclusions The RNA-binding protein SERBP1 is abundantly expressed in human breast cancer and may represent a novel breast tumour marker with prognostic significance. Its potential involvement in the plasminogen activator protease cascade warrants further investigation.
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Affiliation(s)
- Nuran Bektas Serce
- Department of Pathology, University Hospital Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany
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