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Abi Zamer B, Rah B, Jayakumar MN, Abumustafa W, Hamad M, Muhammad JS. DNA methylation-mediated epigenetic regulation of oncogenic RPS2 as a novel therapeutic target and biomarker in hepatocellular carcinoma. Biochem Biophys Res Commun 2024; 696:149453. [PMID: 38181486 DOI: 10.1016/j.bbrc.2023.149453] [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: 11/19/2023] [Revised: 12/21/2023] [Accepted: 12/27/2023] [Indexed: 01/07/2024]
Abstract
Ribosomal Protein S2 (RPS2) has emerged as a potential prognostic biomarker due to its involvement in key cellular processes and its altered expression pattern in certain types of cancer. However, its role in hepatocellular carcinoma (HCC) has yet to be investigated. Herein, we analyzed RPS2 mRNA expression and promoter methylation in HCC patient samples and HepG2 cells. Subsequently, loss-of-function experiments were conducted to determine the function of RPS2 in HCC cells in vitro. Our results revealed that RPS2 mRNA expression is significantly elevated, and its promoter is hypomethylated in HCC patient samples compared to controls. In addition, 5-Azacytidine treatment in HepG2 cells decreased RPS2 promoter methylation level and increased its mRNA expression. RPS2 knockdown in HepG2 cells suppressed cell proliferation and promoted apoptosis. Functional pathway analysis of genes positively and negatively associated with RPS2 expression in HCC showed enrichment in ribosomal biogenesis, translation machinery, cell cycle regulation, and DNA processing. Furthermore, utilizing drug-protein 3D docking, we found that doxorubicin, sorafenib, and 5-Fluorouracil, showed high affinity to the active sites of RPS2, and in vitro treatment with these drugs reduced RPS2 expression. For the first time, we report on DNA methylation-mediated epigenetic regulation of RPS2 and its oncogenic role in HCC. Our findings suggest that RPS2 plays a significant role in the development and progression of HCC, hence its potential prognostic and therapeutic utility. Moreover, as epigenetic changes happen early in cancer development, RPS2 may serve as a potential biomarker for tumor progression.
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Affiliation(s)
- Batoul Abi Zamer
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates; Research Institute of Medical and Health Sciences, University of Sharjah, United Arab Emirates
| | - Bilal Rah
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Manju Nidagodu Jayakumar
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Wafaa Abumustafa
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates; Research Institute of Medical and Health Sciences, University of Sharjah, United Arab Emirates
| | - Mawieh Hamad
- Research Institute of Medical and Health Sciences, University of Sharjah, United Arab Emirates; Department of Medical Laboratory Sciences, College of Health Sciences, University of Sharjah, United Arab Emirates
| | - Jibran Sualeh Muhammad
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates; Research Institute of Medical and Health Sciences, University of Sharjah, United Arab Emirates.
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2
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Landry-Voyer AM, Mir Hassani Z, Avino M, Bachand F. Ribosomal Protein uS5 and Friends: Protein-Protein Interactions Involved in Ribosome Assembly and Beyond. Biomolecules 2023; 13:biom13050853. [PMID: 37238722 DOI: 10.3390/biom13050853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/15/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
Ribosomal proteins are fundamental components of the ribosomes in all living cells. The ribosomal protein uS5 (Rps2) is a stable component of the small ribosomal subunit within all three domains of life. In addition to its interactions with proximal ribosomal proteins and rRNA inside the ribosome, uS5 has a surprisingly complex network of evolutionarily conserved non-ribosome-associated proteins. In this review, we focus on a set of four conserved uS5-associated proteins: the protein arginine methyltransferase 3 (PRMT3), the programmed cell death 2 (PDCD2) and its PDCD2-like (PDCD2L) paralog, and the zinc finger protein, ZNF277. We discuss recent work that presents PDCD2 and homologs as a dedicated uS5 chaperone and PDCD2L as a potential adaptor protein for the nuclear export of pre-40S subunits. Although the functional significance of the PRMT3-uS5 and ZNF277-uS5 interactions remain elusive, we reflect on the potential roles of uS5 arginine methylation by PRMT3 and on data indicating that ZNF277 and PRMT3 compete for uS5 binding. Together, these discussions highlight the complex and conserved regulatory network responsible for monitoring the availability and the folding of uS5 for the formation of 40S ribosomal subunits and/or the role of uS5 in potential extra-ribosomal functions.
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Affiliation(s)
- Anne-Marie Landry-Voyer
- Dept of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Zabih Mir Hassani
- Dept of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Mariano Avino
- Dept of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - François Bachand
- Dept of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
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3
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Wang L, Li C, Chen P, Liu C, Cui Z, Deng S, Yang H. Identification of PDCD2 as a Candidate Target of Andrographolide That Arrests the Tumor Cell Cycle by Human Proteome-Scale Screening. ACS Pharmacol Transl Sci 2022; 5:479-490. [DOI: 10.1021/acsptsci.2c00092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lei Wang
- Beijing Key Laboratory of Traditional Chinese Medicine Basic Research on Prevention and Treatment for Major Diseases, Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Caifeng Li
- Beijing Key Laboratory of Traditional Chinese Medicine Basic Research on Prevention and Treatment for Major Diseases, Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Peng Chen
- Robot intelligence laboratory, Experimental Research Center, China Academy of Chinese Medical Sciences, Dongcheng District, Beijing 100700, China
| | - Chunyuan Liu
- Department of Surgery, Yantai Affiliated Hospital of Binzhou Medical University, Yantai 264100, China
| | - Zhao Cui
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Shiwen Deng
- Beijing Key Laboratory of Traditional Chinese Medicine Basic Research on Prevention and Treatment for Major Diseases, Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Hongjun Yang
- Experimental Research Center, China Academy of Chinese Medical Sciences, Dongcheng District, Beijing 100700, China
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4
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Landry-Voyer AM, Bergeron D, Yague-Sanz C, Baker B, Bachand F. PDCD2 functions as an evolutionarily conserved chaperone dedicated for the 40S ribosomal protein uS5 (RPS2). Nucleic Acids Res 2020; 48:12900-12916. [PMID: 33245768 PMCID: PMC7736825 DOI: 10.1093/nar/gkaa1108] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/23/2020] [Accepted: 10/28/2020] [Indexed: 11/12/2022] Open
Abstract
PDCD2 is an evolutionarily conserved protein with previously characterized homologs in Drosophila (zfrp8) and budding yeast (Tsr4). Although mammalian PDCD2 is essential for cell proliferation and embryonic development, the function of PDCD2 that underlies its fundamental cellular role has remained unclear. Here, we used quantitative proteomics approaches to define the protein-protein interaction network of human PDCD2. Our data revealed that PDCD2 specifically interacts with the 40S ribosomal protein uS5 (RPS2) and that the PDCD2-uS5 complex is assembled co-translationally. Loss of PDCD2 expression leads to defects in the synthesis of the small ribosomal subunit that phenocopy a uS5 deficiency. Notably, we show that PDCD2 is important for the accumulation of soluble uS5 protein as well as its incorporation into 40S ribosomal subunit. Our findings support that the essential molecular function of PDCD2 is to act as a dedicated ribosomal protein chaperone that recognizes uS5 co-translationally in the cytoplasm and accompanies uS5 to ribosome assembly sites in the nucleus. As most dedicated ribosomal protein chaperones have been identified in yeast, our study reveals that similar mechanisms exist in human cells to assist ribosomal proteins coordinate their folding, nuclear import and assembly in pre-ribosomal particles.
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Affiliation(s)
- Anne-Marie Landry-Voyer
- Department of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Danny Bergeron
- Department of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Carlo Yague-Sanz
- Department of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Breac Baker
- Department of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Francois Bachand
- Department of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
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5
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Ribosomes: An Exciting Avenue in Stem Cell Research. Stem Cells Int 2020; 2020:8863539. [PMID: 32695182 PMCID: PMC7362291 DOI: 10.1155/2020/8863539] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 06/12/2020] [Accepted: 06/16/2020] [Indexed: 02/07/2023] Open
Abstract
Stem cell research has focused on genomic studies. However, recent evidence has indicated the involvement of epigenetic regulation in determining the fate of stem cells. Ribosomes play a crucial role in epigenetic regulation, and thus, we focused on the role of ribosomes in stem cells. Majority of living organisms possess ribosomes that are involved in the translation of mRNA into proteins and promote cellular proliferation and differentiation. Ribosomes are stable molecular machines that play a role with changes in the levels of RNA during translation. Recent research suggests that specific ribosomes actively regulate gene expression in multiple cell types, such as stem cells. Stem cells have the potential for self-renewal and differentiation into multiple lineages and, thus, require high efficiency of translation. Ribosomes induce cellular transdifferentiation and reprogramming, and disrupted ribosome synthesis affects translation efficiency, thereby hindering stem cell function leading to cell death and differentiation. Stem cell function is regulated by ribosome-mediated control of stem cell-specific gene expression. In this review, we have presented a detailed discourse on the characteristics of ribosomes in stem cells. Understanding ribosome biology in stem cells will provide insights into the regulation of stem cell function and cellular reprogramming.
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Tsr4 Is a Cytoplasmic Chaperone for the Ribosomal Protein Rps2 in Saccharomyces cerevisiae. Mol Cell Biol 2019; 39:MCB.00094-19. [PMID: 31182640 DOI: 10.1128/mcb.00094-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 06/03/2019] [Indexed: 01/31/2023] Open
Abstract
Eukaryotic ribosome biogenesis requires the action of approximately 200 trans-acting factors and the incorporation of 79 ribosomal proteins (RPs). The delivery of RPs to preribosomes is a major challenge for the cell because RPs are often highly basic and contain intrinsically disordered regions prone to nonspecific interactions and aggregation. To counteract this, eukaryotes developed dedicated chaperones for certain RPs that promote their solubility and expression, often by binding eukaryote-specific extensions of the RPs. Rps2 (uS5) is a universally conserved RP that assembles into nuclear pre-40S subunits. However, a chaperone for Rps2 had not been identified. Our laboratory previously characterized Tsr4 as a 40S biogenesis factor of unknown function. Here, we report that Tsr4 cotranslationally associates with Rps2. Rps2 harbors a eukaryote-specific N-terminal extension that is critical for its interaction with Tsr4. Moreover, Tsr4 perturbation resulted in decreased Rps2 levels and phenocopied Rps2 depletion. Despite Rps2 joining nuclear pre-40S particles, Tsr4 appears to be restricted to the cytoplasm. Thus, we conclude that Tsr4 is a cytoplasmic chaperone dedicated to Rps2.
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7
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Rössler I, Embacher J, Pillet B, Murat G, Liesinger L, Hafner J, Unterluggauer JJ, Birner-Gruenberger R, Kressler D, Pertschy B. Tsr4 and Nap1, two novel members of the ribosomal protein chaperOME. Nucleic Acids Res 2019; 47:6984-7002. [PMID: 31062022 PMCID: PMC6648895 DOI: 10.1093/nar/gkz317] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/15/2019] [Accepted: 04/19/2019] [Indexed: 12/12/2022] Open
Abstract
Dedicated chaperones protect newly synthesized ribosomal proteins (r-proteins) from aggregation and accompany them on their way to assembly into nascent ribosomes. Currently, only nine of the ∼80 eukaryotic r-proteins are known to be guarded by such chaperones. In search of new dedicated r-protein chaperones, we performed a tandem-affinity purification based screen and looked for factors co-enriched with individual small subunit r-proteins. We report the identification of Nap1 and Tsr4 as direct binding partners of Rps6 and Rps2, respectively. Both factors promote the solubility of their r-protein clients in vitro. While Tsr4 is specific for Rps2, Nap1 has several interaction partners including Rps6 and two other r-proteins. Tsr4 binds co-translationally to the essential, eukaryote-specific N-terminal extension of Rps2, whereas Nap1 interacts with a large, mostly eukaryote-specific binding surface of Rps6. Mutation of the essential Tsr4 and deletion of the non-essential Nap1 both enhance the 40S synthesis defects of the corresponding r-protein mutants. Our findings highlight that the acquisition of eukaryote-specific domains in r-proteins was accompanied by the co-evolution of proteins specialized to protect these domains and emphasize the critical role of r-protein chaperones for the synthesis of eukaryotic ribosomes.
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Affiliation(s)
- Ingrid Rössler
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Julia Embacher
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Benjamin Pillet
- Unit of Biochemistry, Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
| | - Guillaume Murat
- Unit of Biochemistry, Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
| | - Laura Liesinger
- BioTechMed-Graz, Graz, Austria
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
- Omics Center Graz, BioTechMed-Graz, Graz, Austria
| | - Jutta Hafner
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Julia Judith Unterluggauer
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Ruth Birner-Gruenberger
- BioTechMed-Graz, Graz, Austria
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
- Omics Center Graz, BioTechMed-Graz, Graz, Austria
| | - Dieter Kressler
- Unit of Biochemistry, Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
| | - Brigitte Pertschy
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria
- BioTechMed-Graz, Graz, Austria
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8
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Yu J, Yan Y, Luan X, Qiao C, Liu Y, Zhao D, Xie B, Zheng Q, Wang M, Chen W, Shen C, He Z, Hu X, Huang X, Li H, Shao Q, Chen X, Zheng B, Fang J. Srlp is crucial for the self-renewal and differentiation of germline stem cells via RpL6 signals in Drosophila testes. Cell Death Dis 2019; 10:294. [PMID: 30931935 PMCID: PMC6443671 DOI: 10.1038/s41419-019-1527-z] [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: 10/10/2018] [Revised: 03/11/2019] [Accepted: 03/14/2019] [Indexed: 12/22/2022]
Abstract
Self-renewal and differentiation in germline stem cells (GSCs) are tightly regulated by the stem cell niche and via multiple approaches. In our previous study, we screened the novel GSC regulatory gene Srlp in Drosophila testes. However, the underlying mechanistic links between Srlp and the stem cell niche remain largely undetermined. Here, using genetic manipulation of the Drosophila model, we systematically analyze the function and mechanism of Srlp in vivo and in vitro. In Drosophila, Srlp is an essential gene that regulates the self-renewal and differentiation of GSCs in the testis. In the in vitro assay, Srlp is found to control the proliferation ability and cell death in S2 cells, which is consistent with the phenotype observed in Drosophila testis. Furthermore, results of the liquid chromatography-tandem mass spectrometry (LC-MS/MS) reveal that RpL6 binds to Srlp. Srlp also regulates the expression of spliceosome and ribosome subunits and controls spliceosome and ribosome function via RpL6 signals. Collectively, our findings uncover the genetic causes and molecular mechanisms underlying the stem cell niche. This study provides new insights for elucidating the pathogenic mechanism of male sterility and the formation of testicular germ cell tumor.
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Affiliation(s)
- Jun Yu
- Department of Gynecology, The Affiliated Hospital of Jiangsu University, Jiangsu University, Zhenjiang Jiangsu, 212001, China.,Reproductive Sciences Institute of Jiangsu University, Zhenjiang Jiangsu, 212001, China
| | - Yidan Yan
- Department of Gynecology, The Affiliated Hospital of Jiangsu University, Jiangsu University, Zhenjiang Jiangsu, 212001, China.,Reproductive Sciences Institute of Jiangsu University, Zhenjiang Jiangsu, 212001, China
| | - Xiaojin Luan
- Department of Gynecology, The Affiliated Hospital of Jiangsu University, Jiangsu University, Zhenjiang Jiangsu, 212001, China.,Reproductive Sciences Institute of Jiangsu University, Zhenjiang Jiangsu, 212001, China
| | - Chen Qiao
- Department of Clinical Pharmacy, the Affiliated Hospital of Jiangsu University, Jiangsu University, Zhenjiang Jiangsu, 212001, China
| | - Yuanyuan Liu
- Center for Reproduction and Genetics, Suzhou Municipal Hospital, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Jiangsu, 215002, China
| | - Dan Zhao
- Reproductive Sciences Institute of Jiangsu University, Zhenjiang Jiangsu, 212001, China.,Center for Reproduction, The Fourth People's Hospital of Zhenjiang, Zhenjiang Jiangsu, 212013, China
| | - Bing Xie
- Department of Gynecology, The Affiliated Hospital of Jiangsu University, Jiangsu University, Zhenjiang Jiangsu, 212001, China
| | - Qianwen Zheng
- Department of Gynecology, The Affiliated Hospital of Jiangsu University, Jiangsu University, Zhenjiang Jiangsu, 212001, China.,Reproductive Sciences Institute of Jiangsu University, Zhenjiang Jiangsu, 212001, China
| | - Min Wang
- Department of Gynecology, The Affiliated Hospital of Jiangsu University, Jiangsu University, Zhenjiang Jiangsu, 212001, China
| | - Wanyin Chen
- Department of Gynecology, The Affiliated Hospital of Jiangsu University, Jiangsu University, Zhenjiang Jiangsu, 212001, China
| | - Cong Shen
- Center for Reproduction and Genetics, Suzhou Municipal Hospital, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Jiangsu, 215002, China
| | - Zeyu He
- Department of Clinical Medicine, China Medical University, Shenyang Liaoning, 110001, China
| | - Xing Hu
- Department of Gynecology, The Affiliated Hospital of Jiangsu University, Jiangsu University, Zhenjiang Jiangsu, 212001, China
| | - Xiaoyan Huang
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, Nanjing Medical University, Nanjing Jiangsu, 211166, China
| | - Hong Li
- Center for Reproduction and Genetics, Suzhou Municipal Hospital, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Jiangsu, 215002, China
| | - Qixiang Shao
- Reproductive Sciences Institute of Jiangsu University, Zhenjiang Jiangsu, 212001, China.,Department of Immunology and Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu University, Zhenjiang Jiangsu, 212013, China
| | - Xia Chen
- Department of Gynecology, The Affiliated Hospital of Jiangsu University, Jiangsu University, Zhenjiang Jiangsu, 212001, China. .,Reproductive Sciences Institute of Jiangsu University, Zhenjiang Jiangsu, 212001, China.
| | - Bo Zheng
- Center for Reproduction and Genetics, Suzhou Municipal Hospital, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Jiangsu, 215002, China.
| | - Jie Fang
- Department of Gynecology, The Affiliated Hospital of Jiangsu University, Jiangsu University, Zhenjiang Jiangsu, 212001, China.
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9
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Dionne KL, Bergeron D, Landry-Voyer AM, Bachand F. The 40S ribosomal protein uS5 (RPS2) assembles into an extraribosomal complex with human ZNF277 that competes with the PRMT3-uS5 interaction. J Biol Chem 2018; 294:1944-1955. [PMID: 30530495 DOI: 10.1074/jbc.ra118.004928] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 11/27/2018] [Indexed: 02/06/2023] Open
Abstract
Ribosomal (r)-proteins are generally viewed as ubiquitous, constitutive proteins that simply function to maintain ribosome integrity. However, findings in the past decade have led to the idea that r-proteins have evolved specialized functions beyond the ribosome. For example, the 40S ribosomal protein uS5 (RPS2) is known to form an extraribosomal complex with the protein arginine methyltransferase PRMT3 that is conserved from fission yeast to humans. However, the full scope of uS5's extraribosomal functions, including whether uS5 interacts with any other proteins, is not known. In this study, we identify the conserved zinc finger protein 277 (ZNF277) as a new uS5-associated protein by using quantitative proteomics approaches in human cells. As previously shown for PRMT3, we found that ZNF277 uses a C2H2-type zinc finger domain to recognize uS5. Analysis of protein-protein interactions in living cells indicated that the ZNF277-uS5 complex is found in the cytoplasm and the nucleolus. Furthermore, we show that ZNF277 and PRMT3 compete for uS5 binding, because overexpression of PRMT3 inhibited the formation of the ZNF277-uS5 complex, whereas depletion of cellular ZNF277 resulted in increased levels of uS5-PRMT3. Notably, our results reveal that ZNF277 recognizes nascent uS5 in the course of mRNA translation, suggesting cotranslational assembly of the ZNF277-uS5 complex. Our findings thus unveil an intricate network of evolutionarily conserved protein-protein interactions involving extraribosomal uS5, suggesting a key role for uS5 beyond the ribosome.
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Affiliation(s)
- Kiersten L Dionne
- From the RNA Group, Department of Biochemistry, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Danny Bergeron
- From the RNA Group, Department of Biochemistry, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Anne-Marie Landry-Voyer
- From the RNA Group, Department of Biochemistry, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - François Bachand
- From the RNA Group, Department of Biochemistry, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
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Human PDCD2L Is an Export Substrate of CRM1 That Associates with 40S Ribosomal Subunit Precursors. Mol Cell Biol 2016; 36:3019-3032. [PMID: 27697862 DOI: 10.1128/mcb.00303-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 09/15/2016] [Indexed: 01/05/2023] Open
Abstract
Protein arginine methyltransferase 3 (PRMT3) forms a stable complex with 40S ribosomal protein S2 (RPS2) and contributes to ribosome biogenesis. However, the molecular mechanism by which PRMT3 influences ribosome biogenesis and/or function still remains unclear. Using quantitative proteomics, we identified human programmed cell death 2-like (PDCD2L) as a novel PRMT3-associated protein. Our data suggest that RPS2 promotes the formation of a conserved extraribosomal complex with PRMT3 and PDCD2L. We also show that PDCD2L associates with 40S subunit precursors that contain a 3'-extended form of the 18S rRNA (18S-E pre-rRNA) and several pre-40S maturation factors. PDCD2L shuttles between the nucleus and the cytoplasm in a CRM1-dependent manner using a leucine-rich nuclear export signal that is sufficient to direct the export of a reporter protein. Although PDCD2L is not required for the biogenesis and export of 40S ribosomal subunits, we found that PDCD2L-null cells accumulate free 60S ribosomal subunits, which is indicative of a deficiency in 40S subunit availability. Our data also indicate that PDCD2L and its paralog, PDCD2, function redundantly in 40S ribosomal subunit production. Our findings uncover the existence of an extraribosomal complex consisting of PDCD2L, RPS2, and PRMT3 and support a role for PDCD2L in the late maturation of 40S ribosomal subunits.
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