1
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Kour R, Kim J, Roy A, Richardson B, Cameron MJ, Knott JG, Mazumder B. Loss of function of ribosomal protein L13a blocks blastocyst formation and reveals a potential nuclear role in gene expression. FASEB J 2023; 37:e23275. [PMID: 37902531 PMCID: PMC10999073 DOI: 10.1096/fj.202301475r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/03/2023] [Accepted: 10/11/2023] [Indexed: 10/31/2023]
Abstract
Ribosomal proteins play diverse roles in development and disease. Most ribosomal proteins have canonical roles in protein synthesis, while some exhibit extra-ribosomal functions. Previous studies in our laboratory revealed that ribosomal protein L13a (RPL13a) is involved in the translational silencing of a cohort of inflammatory proteins in myeloid cells. This prompted us to investigate the role of RPL13a in embryonic development. Here we report that RPL13a is required for early development in mice. Crosses between Rpl13a+/- mice resulted in no Rpl13a-/- offspring. Closer examination revealed that Rpl13a-/- embryos were arrested at the morula stage during preimplantation development. RNA sequencing analysis of Rpl13a-/- morulae revealed widespread alterations in gene expression, including but not limited to several genes encoding proteins involved in the inflammatory response, embryogenesis, oocyte maturation, stemness, and pluripotency. Ex vivo analysis revealed that RPL13a was localized to the cytoplasm and nucleus between the two-cell and morula stages. RNAi-mediated depletion of RPL13a phenocopied Rpl13a-/- embryos and knockdown embryos exhibited increased expression of IL-7 and IL-17 and decreased expression of the lineage specifier genes Sox2, Pou5f1, and Cdx2. Lastly, a protein-protein interaction assay revealed that RPL13a is associated with chromatin, suggesting an extra ribosomal function in transcription. In summary, our data demonstrate that RPL13a is essential for the completion of preimplantation embryo development. The mechanistic basis of the absence of RPL13a-mediated embryonic lethality will be addressed in the future through follow-up studies on ribosome biogenesis, global protein synthesis, and identification of RPL13a target genes using chromatin immunoprecipitation and RNA-immunoprecipitation-based sequencing.
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Affiliation(s)
- Ravinder Kour
- Center for Gene Regulation in Health and Disease, Department of Biological Geological and Environmental Sciences, Cleveland State University, Cleveland, Ohio, USA
| | - Jaehwan Kim
- Developmental Epigenetics Laboratory, Department of Animal Science, Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, Michigan, USA
| | - Antara Roy
- Center for Gene Regulation in Health and Disease, Department of Biological Geological and Environmental Sciences, Cleveland State University, Cleveland, Ohio, USA
| | - Brian Richardson
- Department of Population and Quantitative Health Sciences, Institute for Computational Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Mark J. Cameron
- Department of Population and Quantitative Health Sciences, Institute for Computational Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Jason G. Knott
- Developmental Epigenetics Laboratory, Department of Animal Science, Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, Michigan, USA
| | - Barsanjit Mazumder
- Center for Gene Regulation in Health and Disease, Department of Biological Geological and Environmental Sciences, Cleveland State University, Cleveland, Ohio, USA
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2
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Shirokikh NE, Jensen KB, Thakor N. Editorial: RNA machines. Front Genet 2023; 14:1290420. [PMID: 37829284 PMCID: PMC10565666 DOI: 10.3389/fgene.2023.1290420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 09/18/2023] [Indexed: 10/14/2023] Open
Affiliation(s)
- Nikolay E. Shirokikh
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Kirk Blomquist Jensen
- School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Nehal Thakor
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, Canada
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3
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Xu AF, Molinuevo R, Fazzari E, Tom H, Zhang Z, Menendez J, Casey KM, Ruggero D, Hinck L, Pritchard JK, Barna M. Subfunctionalized expression drives evolutionary retention of ribosomal protein paralogs Rps27 and Rps27l in vertebrates. eLife 2023; 12:e78695. [PMID: 37306301 PMCID: PMC10313321 DOI: 10.7554/elife.78695] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/09/2023] [Indexed: 06/13/2023] Open
Abstract
The formation of paralogs through gene duplication is a core evolutionary process. For paralogs that encode components of protein complexes such as the ribosome, a central question is whether they encode functionally distinct proteins or whether they exist to maintain appropriate total expression of equivalent proteins. Here, we systematically tested evolutionary models of paralog function using the ribosomal protein paralogs Rps27 (eS27) and Rps27l (eS27L) as a case study. Evolutionary analysis suggests that Rps27 and Rps27l likely arose during whole-genome duplication(s) in a common vertebrate ancestor. We show that Rps27 and Rps27l have inversely correlated mRNA abundance across mouse cell types, with the highest Rps27 in lymphocytes and the highest Rps27l in mammary alveolar cells and hepatocytes. By endogenously tagging the Rps27 and Rps27l proteins, we demonstrate that Rps27- and Rps27l-ribosomes associate preferentially with different transcripts. Furthermore, murine Rps27 and Rps27l loss-of-function alleles are homozygous lethal at different developmental stages. However, strikingly, expressing Rps27 protein from the endogenous Rps27l locus or vice versa completely rescues loss-of-function lethality and yields mice with no detectable deficits. Together, these findings suggest that Rps27 and Rps27l are evolutionarily retained because their subfunctionalized expression patterns render both genes necessary to achieve the requisite total expression of two equivalent proteins across cell types. Our work represents the most in-depth characterization of a mammalian ribosomal protein paralog to date and highlights the importance of considering both protein function and expression when investigating paralogs.
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Affiliation(s)
- Adele Francis Xu
- Department of Genetics, Stanford UniversityStanfordUnited States
- Medical Scientist Training Program, Stanford School of MedicineStanfordUnited States
| | - Rut Molinuevo
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa CruzSanta CruzUnited States
| | - Elisa Fazzari
- Helen Diller Family Comprehensive Cancer Center, University of California, Los AngelesLos AngelesUnited States
- Department of Cellular and Molecular Pharmacology, University of California, San FranciscoSan FranciscoUnited States
- Department of Urology, University of California, San FranciscoSan FranciscoUnited States
| | - Harrison Tom
- Helen Diller Family Comprehensive Cancer Center, University of California, Los AngelesLos AngelesUnited States
- Department of Cellular and Molecular Pharmacology, University of California, San FranciscoSan FranciscoUnited States
- Department of Urology, University of California, San FranciscoSan FranciscoUnited States
| | - Zijian Zhang
- Department of Chemical and Systems Biology, Stanford UniversityStanfordUnited States
| | - Julien Menendez
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa CruzSanta CruzUnited States
| | - Kerriann M Casey
- Department of Biology, Stanford UniversityStanfordUnited States
- Department of Comparative Medicine, Stanford School of MedicineStanfordUnited States
| | - Davide Ruggero
- Department of Cellular and Molecular Pharmacology, University of California, San FranciscoSan FranciscoUnited States
- Department of Urology, University of California, San FranciscoSan FranciscoUnited States
| | - Lindsay Hinck
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa CruzSanta CruzUnited States
| | | | - Maria Barna
- Department of Genetics, Stanford UniversityStanfordUnited States
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4
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Saha S, Lõhmus A, Dutta P, Pollari M, Mäkinen K. Interplay of HCPro and CP in the Regulation of Potato Virus A RNA Expression and Encapsidation. Viruses 2022; 14:1233. [PMID: 35746704 PMCID: PMC9227828 DOI: 10.3390/v14061233] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/27/2022] [Accepted: 06/03/2022] [Indexed: 12/04/2022] Open
Abstract
Potyviral coat protein (CP) and helper component-proteinase (HCPro) play key roles in both the regulation of viral gene expression and the formation of viral particles. We investigated the interplay between CP and HCPro during these viral processes. While the endogenous HCPro and a heterologous viral suppressor of gene silencing both complemented HCPro-less potato virus A (PVA) expression, CP stabilization connected to particle formation could be complemented only by the cognate PVA HCPro. We found that HCPro relieves CP-mediated inhibition of PVA RNA expression likely by enabling HCPro-mediated sequestration of CPs to particles. We addressed the question about the role of replication in formation of PVA particles and gained evidence for encapsidation of non-replicating PVA RNA. The extreme instability of these particles substantiates the need for replication in the formation of stable particles. During replication, viral protein genome linked (VPg) becomes covalently attached to PVA RNA and can attract HCPro, cylindrical inclusion protein and host proteins. Based on the results of the current study and our previous findings we propose a model in which a large ribonucleoprotein complex formed around VPg at one end of PVA particles is essential for their integrity.
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Affiliation(s)
| | | | | | | | - Kristiina Mäkinen
- Department of Microbiology, Viikki Plant Science Centre, University of Helsinki, 00014 Helsinki, Finland; (S.S.); (A.L.); (P.D.); (M.P.)
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5
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Cheng Y, Li Y, Li W, Song Y, Zeng R, Lu K. Effect of hepatocyte nuclear factor 4 on the fecundity of Nilaparvata lugens: Insights from RNA interference combined with transcriptomic analysis. Genomics 2020; 112:4585-4594. [DOI: 10.1016/j.ygeno.2020.08.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/18/2020] [Accepted: 08/01/2020] [Indexed: 12/30/2022]
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6
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Schieweck R, Ninkovic J, Kiebler MA. RNA-binding proteins balance brain function in health and disease. Physiol Rev 2020; 101:1309-1370. [PMID: 33000986 DOI: 10.1152/physrev.00047.2019] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Posttranscriptional gene expression including splicing, RNA transport, translation, and RNA decay provides an important regulatory layer in many if not all molecular pathways. Research in the last decades has positioned RNA-binding proteins (RBPs) right in the center of posttranscriptional gene regulation. Here, we propose interdependent networks of RBPs to regulate complex pathways within the central nervous system (CNS). These are involved in multiple aspects of neuronal development and functioning, including higher cognition. Therefore, it is not sufficient to unravel the individual contribution of a single RBP and its consequences but rather to study and understand the tight interplay between different RBPs. In this review, we summarize recent findings in the field of RBP biology and discuss the complex interplay between different RBPs. Second, we emphasize the underlying dynamics within an RBP network and how this might regulate key processes such as neurogenesis, synaptic transmission, and synaptic plasticity. Importantly, we envision that dysfunction of specific RBPs could lead to perturbation within the RBP network. This would have direct and indirect (compensatory) effects in mRNA binding and translational control leading to global changes in cellular expression programs in general and in synaptic plasticity in particular. Therefore, we focus on RBP dysfunction and how this might cause neuropsychiatric and neurodegenerative disorders. Based on recent findings, we propose that alterations in the entire regulatory RBP network might account for phenotypic dysfunctions observed in complex diseases including neurodegeneration, epilepsy, and autism spectrum disorders.
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Affiliation(s)
- Rico Schieweck
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
| | - Jovica Ninkovic
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
| | - Michael A Kiebler
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
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7
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Jin X, Wang J, Zou S, Xu R, Cao J, Zhang Y, Guo J, Wen X, Deng S, Zheng Y, Zhu Y, Wang F, Xu Z. Cinobufagin Triggers Defects in Spindle Formation and Cap-Dependent Translation in Liver Cancer Cells by Inhibiting the AURKA-mTOR-eIF4E Axis. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2020; 48:651-678. [PMID: 32349518 DOI: 10.1142/s0192415x20500330] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Cinobufagin is a Na+/K+-ATPase (NKA) inhibitor with excellent anticancer effects to prolong the survival of patients. The purpose of the present study was to clarify the underlying mechanism of the anticancer effects of cinobufagin using overexpression or inhibition of aurora kinase A (AURKA) signaling. First, high expression of Na+/K+-ATPase alpha 1 subunit (ATP1A1) and AURAK resulted in increased malignant transformation in hepatocellular carcinoma (HCC) patients using the cancer genome atlas (TCGA) data and tissue samples. After treatment with cinobufagin, we successfully screened 202, 249, and 335 changing expression proteins in Huh-7 cells under normal, overexpression, and inhibition of AURKA using tandem mass tags (TMT)-labeled quantitative proteomics coupled to 2D liquid chromatography-tandem mass spectrometry (LC-MS/MS). Bioinformatics analysis revealed that these molecules were closely associated with chromosome segregation, DNA damage, and regulation of translation processes. We further confirmed that cinobufagin induced DNA damage and chromosome segregation disorders and suppresses translational processing in oncogenes by decreasing the expression of AURKA, mechanistic target of rapamycin kinase (mTOR), p-mTOR, p-extracellular regulated protein kinases (ERK), eukaryotic translation initiation factor 4E (eIF4E), and p-eIF4E, while increasing the expression of p-eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1) (S65, T37, T46, T45) and increasing the interaction between eIF4 and 4E-BP1. Our results suggested that cinobufagin performed an antitumor effects in liver cancer cells by inhibiting the AURKA-mTOR-eIF4E axis.
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Affiliation(s)
- Xiaohan Jin
- Central Laboratory, Logistics University of Chinese People’s Armed Police Force, Tianjin City 300309, P. R. China
| | - Jiabao Wang
- Central Laboratory, Logistics University of Chinese People’s Armed Police Force, Tianjin City 300309, P. R. China
| | - Shuang Zou
- Central Laboratory, Logistics University of Chinese People’s Armed Police Force, Tianjin City 300309, P. R. China
| | - Ruicheng Xu
- Central Laboratory, Logistics University of Chinese People’s Armed Police Force, Tianjin City 300309, P. R. China
| | - Jin Cao
- Department of Gastroenterology and Hepatology, Third Central Hospital of Tianjin, Tianjin City 300170, P. R. China
| | - Yan Zhang
- Central Laboratory, Logistics University of Chinese People’s Armed Police Force, Tianjin City 300309, P. R. China
| | - Jia Guo
- Central Laboratory, Logistics University of Chinese People’s Armed Police Force, Tianjin City 300309, P. R. China
| | - Xiaochang Wen
- Central Laboratory, Logistics University of Chinese People’s Armed Police Force, Tianjin City 300309, P. R. China
| | - Sanmin Deng
- Central Laboratory, Logistics University of Chinese People’s Armed Police Force, Tianjin City 300309, P. R. China
| | - Yupiao Zheng
- Department of Gastroenterology and Hepatology, Third Central Hospital of Tianjin, Tianjin City 300170, P. R. China
| | - Yu Zhu
- Department of Clinical Laboratory, Tianjin Key Laboratory of Cerebral Vessels and Neurodegenerative Diseases, Tianjin Huanhu Hospital, Tianjin City 300350, P. R. China
| | - Fengmei Wang
- Department of Gastroenterology and Hepatology, Third Central Hospital of Tianjin, Tianjin City 300170, P. R. China
| | - Zhongwei Xu
- Central Laboratory, Logistics University of Chinese People’s Armed Police Force, Tianjin City 300309, P. R. China
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8
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Saha S, Mäkinen K. Insights into the Functions of eIF4E-Biding Motif of VPg in Potato Virus A Infection. Viruses 2020; 12:E197. [PMID: 32053987 PMCID: PMC7077193 DOI: 10.3390/v12020197] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 02/05/2020] [Accepted: 02/07/2020] [Indexed: 12/14/2022] Open
Abstract
The interaction between the viral protein genome-linked (VPg) and eukaryotic initiation factor 4E (eIF4E) or eIF(iso)4E of the host plays a crucial role in potyvirus infection. The VPg of potato virus A (PVA) contains the Tyr-X-X-X-X-Leu-phi (YXXXLΦ) binding motif for eIF(iso)4E. In order to investigate its role in PVA infection, we substituted the conserved tyrosine and leucine residues of the motif with alanine residues in the infectious cDNA of PVA (PVAVPgmut). PVAVPgmut RNA replicated in infiltrated leaves, but RNA accumulation remained low. Systemic infection occurred only if a reversion to wild type PVA occurred. VPg was able to stabilize PVA RNA and enhance the expression of Renilla luciferase (3'RLUC) from the 3' end of the PVA genome. VPgmut could not support either PVA RNA stabilization or enhanced 3'RLUC expression. The RNA silencing suppressor helper-component proteinase (HCPro) is responsible for the formation of PVA-induced RNA granules (PGs) during infection. While VPgmut increased the number of PG-like foci, the percentage of PVA RNA co-localization with PGs was reduced from 86% to 20%. A testable hypothesis for future studies based on these results is that the binding of eIF(iso)4E to PVA VPg via the YXXXLΦ motif is required for PVA RNA stabilization, as well as the transfer to the RNA silencing suppression pathway and, further, to polysomes for viral protein synthesis.
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Affiliation(s)
| | - Kristiina Mäkinen
- Department of Microbiology and Viikki Plant Science Centre, University of Helsinki, 00014 Helsinki, Finland;
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9
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Translational control of depression-like behavior via phosphorylation of eukaryotic translation initiation factor 4E. Nat Commun 2018; 9:2459. [PMID: 29941989 PMCID: PMC6018502 DOI: 10.1038/s41467-018-04883-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/11/2018] [Indexed: 12/27/2022] Open
Abstract
Translation of mRNA into protein has a fundamental role in neurodevelopment, plasticity, and memory formation; however, its contribution in the pathophysiology of depressive disorders is not fully understood. We investigated the involvement of MNK1/2 (MAPK-interacting serine/threonine-protein kinase 1 and 2) and their target, eIF4E (eukaryotic initiation factor 4E), in depression-like behavior in mice. Mice carrying a mutation in eIF4E for the MNK1/2 phosphorylation site (Ser209Ala, Eif4e ki/ki), the Mnk1/2 double knockout mice (Mnk1/2-/-), or mice treated with the MNK1/2 inhibitor, cercosporamide, displayed anxiety- and depression-like behaviors, impaired serotonin-induced excitatory synaptic activity in the prefrontal cortex, and diminished firing of the dorsal raphe neurons. In Eif4e ki/ki mice, brain IκBα, was decreased, while the NF-κB target, TNFα was elevated. TNFα inhibition in Eif4e ki/ki mice rescued, whereas TNFα administration to wild-type mice mimicked the depression-like behaviors and 5-HT synaptic deficits. We conclude that eIF4E phosphorylation modulates depression-like behavior through regulation of inflammatory responses.
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10
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Liu HH, McClatchy DB, Schiapparelli L, Shen W, Yates JR, Cline HT. Role of the visual experience-dependent nascent proteome in neuronal plasticity. eLife 2018; 7:e33420. [PMID: 29412139 PMCID: PMC5815848 DOI: 10.7554/elife.33420] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 02/05/2018] [Indexed: 01/02/2023] Open
Abstract
Experience-dependent synaptic plasticity refines brain circuits during development. To identify novel protein synthesis-dependent mechanisms contributing to experience-dependent plasticity, we conducted a quantitative proteomic screen of the nascent proteome in response to visual experience in Xenopus optic tectum using bio-orthogonal metabolic labeling (BONCAT). We identified 83 differentially synthesized candidate plasticity proteins (CPPs). The CPPs form strongly interconnected networks and are annotated to a variety of biological functions, including RNA splicing, protein translation, and chromatin remodeling. Functional analysis of select CPPs revealed the requirement for eukaryotic initiation factor three subunit A (eIF3A), fused in sarcoma (FUS), and ribosomal protein s17 (RPS17) in experience-dependent structural plasticity in tectal neurons and behavioral plasticity in tadpoles. These results demonstrate that the nascent proteome is dynamic in response to visual experience and that de novo synthesis of machinery that regulates RNA splicing and protein translation is required for experience-dependent plasticity.
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Affiliation(s)
- Han-Hsuan Liu
- The Dorris Neuroscience CenterThe Scripps Research InstituteLa JollaUnited States
- Department of NeuroscienceThe Scripps Research InstituteLa JollaUnited States
- Kellogg School of Science and TechnologyThe Scripps Research InstituteLa JollaUnited States
| | - Daniel B McClatchy
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaUnited States
| | - Lucio Schiapparelli
- The Dorris Neuroscience CenterThe Scripps Research InstituteLa JollaUnited States
- Department of NeuroscienceThe Scripps Research InstituteLa JollaUnited States
| | - Wanhua Shen
- The Dorris Neuroscience CenterThe Scripps Research InstituteLa JollaUnited States
- Department of NeuroscienceThe Scripps Research InstituteLa JollaUnited States
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental SciencesHangzhou Normal UniversityHangzhouChina
| | - John R Yates
- Department of NeuroscienceThe Scripps Research InstituteLa JollaUnited States
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaUnited States
| | - Hollis T Cline
- The Dorris Neuroscience CenterThe Scripps Research InstituteLa JollaUnited States
- Department of NeuroscienceThe Scripps Research InstituteLa JollaUnited States
- Kellogg School of Science and TechnologyThe Scripps Research InstituteLa JollaUnited States
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaUnited States
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11
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Geter PA, Ernlund AW, Bakogianni S, Alard A, Arju R, Giashuddin S, Gadi A, Bromberg J, Schneider RJ. Hyperactive mTOR and MNK1 phosphorylation of eIF4E confer tamoxifen resistance and estrogen independence through selective mRNA translation reprogramming. Genes Dev 2017; 31:2235-2249. [PMID: 29269484 PMCID: PMC5769768 DOI: 10.1101/gad.305631.117] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 11/20/2017] [Indexed: 01/04/2023]
Abstract
Geter et al. show that tamoxifen resistance involves selective mRNA translational reprogramming to an anti-estrogen state by Runx2 and other mRNAs. Tamoxifen-resistant translational reprogramming is shown to be mediated by increased expression of eIF4E and its increased availability by hyperactive mTOR and to require phosphorylation of eIF4E at Ser209 by increased MNK activity. The majority of breast cancers expresses the estrogen receptor (ER+) and is treated with anti-estrogen therapies, particularly tamoxifen in premenopausal women. However, tamoxifen resistance is responsible for a large proportion of breast cancer deaths. Using small molecule inhibitors, phospho-mimetic proteins, tamoxifen-sensitive and tamoxifen-resistant breast cancer cells, a tamoxifen-resistant patient-derived xenograft model, patient tumor tissues, and genome-wide transcription and translation studies, we show that tamoxifen resistance involves selective mRNA translational reprogramming to an anti-estrogen state by Runx2 and other mRNAs. Tamoxifen-resistant translational reprogramming is shown to be mediated by increased expression of eIF4E and its increased availability by hyperactive mTOR and to require phosphorylation of eIF4E at Ser209 by increased MNK activity. Resensitization to tamoxifen is restored only by reducing eIF4E expression or mTOR activity and also blocking MNK1 phosphorylation of eIF4E. mRNAs specifically translationally up-regulated with tamoxifen resistance include Runx2, which inhibits ER signaling and estrogen responses and promotes breast cancer metastasis. Silencing Runx2 significantly restores tamoxifen sensitivity. Tamoxifen-resistant but not tamoxifen-sensitive patient ER+ breast cancer specimens also demonstrate strongly increased MNK phosphorylation of eIF4E. eIF4E levels, availability, and phosphorylation therefore promote tamoxifen resistance in ER+ breast cancer through selective mRNA translational reprogramming
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Affiliation(s)
- Phillip A Geter
- Department of Microbiology, Alexandria Center for Life Science, New York University School of Medicine, New York, New York 10016, USA
| | - Amanda W Ernlund
- Department of Microbiology, Alexandria Center for Life Science, New York University School of Medicine, New York, New York 10016, USA
| | - Sofia Bakogianni
- Department of Microbiology, Alexandria Center for Life Science, New York University School of Medicine, New York, New York 10016, USA
| | - Amandine Alard
- Department of Microbiology, Alexandria Center for Life Science, New York University School of Medicine, New York, New York 10016, USA
| | - Rezina Arju
- Department of Microbiology, Alexandria Center for Life Science, New York University School of Medicine, New York, New York 10016, USA
| | - Shah Giashuddin
- New York Presbyterian-Brooklyn Methodist Hospital, Brooklyn, New York 11215, USA
| | - Abhilash Gadi
- Department of Microbiology, Alexandria Center for Life Science, New York University School of Medicine, New York, New York 10016, USA
| | - Jacqueline Bromberg
- Memorial Sloan Kettering Cancer Institute, New York, New York 10016 USA.,Perlmutter Cancer Center, New York University School of Medicine, New York, New York 10016 USA
| | - Robert J Schneider
- Department of Microbiology, Alexandria Center for Life Science, New York University School of Medicine, New York, New York 10016, USA.,Memorial Sloan Kettering Cancer Institute, New York, New York 10016 USA.,Perlmutter Cancer Center, New York University School of Medicine, New York, New York 10016 USA
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12
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Definition of a RACK1 Interaction Network in Drosophila melanogaster Using SWATH-MS. G3-GENES GENOMES GENETICS 2017; 7:2249-2258. [PMID: 28522639 PMCID: PMC5499132 DOI: 10.1534/g3.117.042564] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Receptor for Activated protein C kinase 1 (RACK1) is a scaffold protein that has been found in association with several signaling complexes, and with the 40S subunit of the ribosome. Using the model organism Drosophila melanogaster, we recently showed that RACK1 is required at the ribosome for internal ribosome entry site (IRES)-mediated translation of viruses. Here, we report a proteomic characterization of the interactome of RACK1 in Drosophila S2 cells. We carried out Label-Free quantitation using both Data-Dependent and Data-Independent Acquisition (DDA and DIA, respectively) and observed a significant advantage for the Sequential Window Acquisition of all THeoretical fragment-ion spectra (SWATH) method, both in terms of identification of interactants and quantification of low abundance proteins. These data represent the first SWATH spectral library available for Drosophila and will be a useful resource for the community. A total of 52 interacting proteins were identified, including several molecules involved in translation such as structural components of the ribosome, factors regulating translation initiation or elongation, and RNA binding proteins. Among these 52 proteins, 15 were identified as partners by the SWATH strategy only. Interestingly, these 15 proteins are significantly enriched for the functions translation and nucleic acid binding. This enrichment reflects the engagement of RACK1 at the ribosome and highlights the added value of SWATH analysis. A functional screen did not reveal any protein sharing the interesting properties of RACK1, which is required for IRES-dependent translation and not essential for cell viability. Intriguingly however, 10 of the RACK1 partners identified restrict replication of Cricket paralysis virus (CrPV), an IRES-containing virus.
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13
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Wang X, Chen L, Yang A, Bu C, He Y. Quantitative Proteomics Analysis of Developmental Reprogramming in Protoplasts of the Moss Physcomitrella patens. PLANT & CELL PHYSIOLOGY 2017; 58:946-961. [PMID: 28398533 DOI: 10.1093/pcp/pcx039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 03/13/2017] [Indexed: 06/07/2023]
Abstract
The moss Physcomitrella patens is a model system for studying Plant developmental processes. To better understand the biochemical and physiological changes involved in developmental reprogramming, we conducted a quantitative proteomics analysis for protonemata, protoplasts made therefrom and protoplasts regenerated for 2 d. Using an iTRAQ peptide labeling strategy and liquid chromatography-tandem mass spectrometry (LC-MS/MS), >3,000 peptides and 1,000 proteins were quantified. Of these, 162 proteins were identified as having differential abundances during developmental reprogramming. These proteins were involved in various biological functions, such as defense, energy production, translation, metabolism, protein destination and storage, transcription, transport, cell growth/division, cell structure and signal transduction. Of these, the proteins involved in energy production and translation increased in abundance, while many of the metabolism and defense proteins decreased in abundance. In addition, most of the cell growth/division, protein stability and cell structure proteins were also down-regulated. This is the first report on the metabolic changes involved in developmental reprogramming in protoplasts. The significance of metabolic networks in developmental programming is beginning to emerge. Our study suggested that stress signals, energy metabolism and ribosomal proteins are pivotal components during developmental programming.
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Affiliation(s)
- Xiaoqin Wang
- Key Laboratory of Urban Agriculture (North China), Ministry of Agriculture, Beijing University of Agriculture, Beijing, China
- Beijing Collaborative Innovation Center for Eco-environmental Improvement with Forestry and Fruit trees, Beijing University of Agriculture, Beijing, China
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Lu Chen
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Aizhen Yang
- Key Laboratory of Urban Agriculture (North China), Ministry of Agriculture, Beijing University of Agriculture, Beijing, China
| | - Chunya Bu
- Key Laboratory of Urban Agriculture (North China), Ministry of Agriculture, Beijing University of Agriculture, Beijing, China
| | - Yikun He
- College of Life Sciences, Capital Normal University, Beijing, China
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14
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Shao J, Stout I, Hendriksen PJM, van Loveren H, Peijnenburg AACM, Volger OL. Protein phosphorylation profiling identifies potential mechanisms for direct immunotoxicity. J Immunotoxicol 2015; 13:97-107. [PMID: 25715851 DOI: 10.3109/1547691x.2015.1016635] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Signaling networks are essential elements that are involved in diverse cellular processes. One group of fundamental components in various signaling pathways concerns protein tyrosine kinases (PTK). Various toxicants have been demonstrated to exert their toxicity via modulation of tyrosine kinase activity. The present study aimed to identify common cellular signaling pathways that are involved in chemical-induced direct immunotoxicity. To this end, an antibody array-based profiling approach was applied to assess effects of five immunotoxicants, two immunosuppressive drugs and two non-immunotoxic control chemicals on the phosphorylation of 28 receptor tyrosine kinases and 11 crucial signaling nodes in Jurkat T-cells. The phosphorylation of ribosomal protein S6 (RPS6) and of kinases Akt, Src and p44/42 were found to be commonly regulated by immunotoxicants and/or immunosuppressive drugs (at least three compounds), with the largest effect observed upon RPS6. Flow cytometry and Western blotting were used to further examine the effect of the model immunotoxicant TBTO on the components of the mTOR-p70S6K-RPS6 pathway. These analyses revealed that both TBTO and the mTOR inhibitor rapamycin inactivate RPS6, but via different mechanisms. Finally, a comparison of the protein phosphorylation data to previously obtained transcriptome data of TBTO-treated Jurkat cells resulted in a good correlation at the pathway level and indicated that TBTO affects ribosome biogenesis and leukocyte migration. The effect of TBTO on the latter process was confirmed using a CXCL12 chemotaxis assay.
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Affiliation(s)
- Jia Shao
- a RIKILT-Institute of Food Safety, Wageningen University and Research Centre , Wageningen , the Netherlands .,b Department of Toxicogenomics , Maastricht University , the Netherlands .,c Netherlands Toxicogenomics Centre , the Netherlands , and
| | - Inge Stout
- a RIKILT-Institute of Food Safety, Wageningen University and Research Centre , Wageningen , the Netherlands
| | - Peter J M Hendriksen
- a RIKILT-Institute of Food Safety, Wageningen University and Research Centre , Wageningen , the Netherlands .,c Netherlands Toxicogenomics Centre , the Netherlands , and
| | - Henk van Loveren
- b Department of Toxicogenomics , Maastricht University , the Netherlands .,c Netherlands Toxicogenomics Centre , the Netherlands , and.,d National Institute for Public Health and the Environment (RIVM) , Bilthoven , the Netherlands
| | - Ad A C M Peijnenburg
- a RIKILT-Institute of Food Safety, Wageningen University and Research Centre , Wageningen , the Netherlands .,c Netherlands Toxicogenomics Centre , the Netherlands , and
| | - Oscar L Volger
- a RIKILT-Institute of Food Safety, Wageningen University and Research Centre , Wageningen , the Netherlands .,c Netherlands Toxicogenomics Centre , the Netherlands , and
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15
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Chicher J, Simonetti A, Kuhn L, Schaeffer L, Hammann P, Eriani G, Martin F. Purification of mRNA-programmed translation initiation complexes suitable for mass spectrometry analysis. Proteomics 2015; 15:2417-25. [PMID: 25914180 DOI: 10.1002/pmic.201400628] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Revised: 02/27/2015] [Accepted: 04/21/2015] [Indexed: 12/21/2022]
Abstract
Liquid Chromatography coupled to tandem mass spectrometry (nanoLC-MS/MS) is a powerful analytical technique for the identification and mass analysis of complex protein mixtures. Here, we present a combination of methods developed for the extensive/deep proteomic analysis of purified ribosome/mRNA particles assembled in rabbit reticulocyte lysate (RRL). Ribosomes are assembled on chimeric biotinylated mRNA-DNA molecules immobilized on streptavidin-coated beads and incubated with RRL to form initiation complexes. After washing steps, the complexes are trypsin-digested directly on the beads in semi-native condition or after their elution from the beads in denaturing Laemmli buffer. The nanoLC-MS/MS analysis performed on complexes assembled on β-globin, viral HCV, and histone H4 mRNAs revealed significant differences in initiation factors composition in agreement with models of translation initiation used by these different types of mRNAs. Using Laemmli-denaturing condition induces release of deeply buried peptides from the ribosome and eukaryotic initiation factor 3 (eIF3) allowing the identification of the nearly complete set of ribosomal proteins.
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Affiliation(s)
- Johana Chicher
- Institut de Biologie Moléculaire et Cellulaire, Plateforme Protéomique Strasbourg - Esplanade, Université De Strasbourg, Strasbourg, France
| | - Angelita Simonetti
- Institut de Biologie Moléculaire et Cellulaire, "Architecture et Réactivité de l'ARN", Université De Strasbourg, Strasbourg, France
| | - Lauriane Kuhn
- Institut de Biologie Moléculaire et Cellulaire, Plateforme Protéomique Strasbourg - Esplanade, Université De Strasbourg, Strasbourg, France
| | - Laure Schaeffer
- Institut de Biologie Moléculaire et Cellulaire, "Architecture et Réactivité de l'ARN", Université De Strasbourg, Strasbourg, France
| | - Philippe Hammann
- Institut de Biologie Moléculaire et Cellulaire, Plateforme Protéomique Strasbourg - Esplanade, Université De Strasbourg, Strasbourg, France
| | - Gilbert Eriani
- Institut de Biologie Moléculaire et Cellulaire, "Architecture et Réactivité de l'ARN", Université De Strasbourg, Strasbourg, France
| | - Franck Martin
- Institut de Biologie Moléculaire et Cellulaire, "Architecture et Réactivité de l'ARN", Université De Strasbourg, Strasbourg, France
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16
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Majzoub K, Hafirassou ML, Meignin C, Goto A, Marzi S, Fedorova A, Verdier Y, Vinh J, Hoffmann JA, Martin F, Baumert TF, Schuster C, Imler JL. RACK1 controls IRES-mediated translation of viruses. Cell 2015; 159:1086-1095. [PMID: 25416947 DOI: 10.1016/j.cell.2014.10.041] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 09/16/2014] [Accepted: 10/20/2014] [Indexed: 01/31/2023]
Abstract
Fighting viral infections is hampered by the scarcity of viral targets and their variability, resulting in development of resistance. Viruses depend on cellular molecules-which are attractive alternative targets-for their life cycle, provided that they are dispensable for normal cell functions. Using the model organism Drosophila melanogaster, we identify the ribosomal protein RACK1 as a cellular factor required for infection by internal ribosome entry site (IRES)-containing viruses. We further show that RACK1 is an essential determinant for hepatitis C virus translation and infection, indicating that its function is conserved for distantly related human and fly viruses. Inhibition of RACK1 does not affect Drosophila or human cell viability and proliferation, and RACK1-silenced adult flies are viable, indicating that this protein is not essential for general translation. Our findings demonstrate a specific function for RACK1 in selective mRNA translation and uncover a target for the development of broad antiviral intervention.
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Affiliation(s)
- Karim Majzoub
- CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France
| | - Mohamed Lamine Hafirassou
- Université de Strasbourg, 67000 Strasbourg, France; Inserm UMR1110, Institut de Recherche sur les Maladies Virales et Hépatiques, 67000 Strasbourg, France
| | - Carine Meignin
- CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Akira Goto
- CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France
| | - Stefano Marzi
- CNRS UPR9002, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France
| | - Antonina Fedorova
- Université de Strasbourg, 67000 Strasbourg, France; Inserm UMR1110, Institut de Recherche sur les Maladies Virales et Hépatiques, 67000 Strasbourg, France
| | | | - Joëlle Vinh
- USR3149, ESPCI ParisTech, 75005 Paris, France
| | - Jules A Hoffmann
- CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France; Université de Strasbourg, 67000 Strasbourg, France; Institut d'Etudes Avancées de l'Université de Strasbourg, 67000 Strasbourg, France
| | - Franck Martin
- CNRS UPR9002, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France
| | - Thomas F Baumert
- Université de Strasbourg, 67000 Strasbourg, France; Inserm UMR1110, Institut de Recherche sur les Maladies Virales et Hépatiques, 67000 Strasbourg, France; Institut Hospitalo-Universitaire (IHU), Pôle hépato-digestif, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France
| | - Catherine Schuster
- Université de Strasbourg, 67000 Strasbourg, France; Inserm UMR1110, Institut de Recherche sur les Maladies Virales et Hépatiques, 67000 Strasbourg, France.
| | - Jean-Luc Imler
- CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France; Université de Strasbourg, 67000 Strasbourg, France.
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17
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Viero G, Lunelli L, Passerini A, Bianchini P, Gilbert RJ, Bernabò P, Tebaldi T, Diaspro A, Pederzolli C, Quattrone A. Three distinct ribosome assemblies modulated by translation are the building blocks of polysomes. ACTA ACUST UNITED AC 2015; 208:581-96. [PMID: 25713412 PMCID: PMC4347638 DOI: 10.1083/jcb.201406040] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Translation is increasingly recognized as a central control layer of gene expression in eukaryotic cells. The overall organization of mRNA and ribosomes within polysomes, as well as the possible role of this organization in translation are poorly understood. Here we show that polysomes are primarily formed by three distinct classes of ribosome assemblies. We observe that these assemblies can be connected by naked RNA regions of the transcript. We show that the relative proportions of the three classes of ribosome assemblies reflect, and probably dictate, the level of translational activity. These results reveal the existence of recurrent supra-ribosomal building blocks forming polysomes and suggest the presence of unexplored translational controls embedded in the polysome structure.
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Affiliation(s)
- Gabriella Viero
- Institute of Biophysics, National Research Council (CNR) Unit at Trento, 38123 Povo, Italy Laboratory of Translational Genomics, Centre for Integrative Biology, University of Trento, 38123 Mattarello, Italy
| | - Lorenzo Lunelli
- Laboratory of Biomolecular Sequence and Structure Analysis for Health, Fondazione Bruno Kessler, 38123 Povo, Italy
| | - Andrea Passerini
- Department of Information Engineering and Computer Science, University of Trento, 38123 Povo, Italy
| | - Paolo Bianchini
- Nanophysics Department, Italian Institute of Technology, 16163 Genova, Italy
| | - Robert J Gilbert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, England, UK
| | - Paola Bernabò
- Institute of Biophysics, National Research Council (CNR) Unit at Trento, 38123 Povo, Italy
| | - Toma Tebaldi
- Laboratory of Translational Genomics, Centre for Integrative Biology, University of Trento, 38123 Mattarello, Italy
| | - Alberto Diaspro
- Nanophysics Department, Italian Institute of Technology, 16163 Genova, Italy
| | - Cecilia Pederzolli
- Laboratory of Biomolecular Sequence and Structure Analysis for Health, Fondazione Bruno Kessler, 38123 Povo, Italy
| | - Alessandro Quattrone
- Laboratory of Translational Genomics, Centre for Integrative Biology, University of Trento, 38123 Mattarello, Italy
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18
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Akabayov SR, Wagner G. Backbone resonance assignment of the HEAT1-domain of the human eukaryotic translation initiation factor 4GI. BIOMOLECULAR NMR ASSIGNMENTS 2014; 8:89-91. [PMID: 23325513 PMCID: PMC3640741 DOI: 10.1007/s12104-013-9459-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 01/04/2013] [Indexed: 06/01/2023]
Abstract
Controlling translation during protein synthesis is crucial for cell proliferation and differentiation. Protein translation is orchestrated by an assembly of various protein components at the ribosomal subunits. The eukaryotic translation initiation factor 4G (eIF4G) plays an important role in the formation of the translation initiation complex eIF4F consisting of eIF4G, the ATP dependent RNA helicase eIF4A and the cap binding protein eIF4E. One of the functions of eIF4G is the enhancement of the activity of eIF4A facilitated mainly through binding to the HEAT1 domain of eIF4G. In order to understand the interaction of HEAT1 with eIF4A and other components during translation initiation backbone assignment is essential. Here we report the (1)H, (13)C and (15)N backbone assignment for the HEAT1 domain of human eIF4G isoform I (eIF4GI-HEAT1), the first of three HEAT domains of eIF4G (29 kDa) as a basis for the elucidation of its structure and interactions with its binding partners, necessary for understanding the mechanism of its biological function.
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Affiliation(s)
- Sabine R Akabayov
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA, 02115, USA
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19
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Relative specificity: all substrates are not created equal. GENOMICS PROTEOMICS & BIOINFORMATICS 2014; 12:1-7. [PMID: 24491634 PMCID: PMC4411342 DOI: 10.1016/j.gpb.2014.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 12/21/2013] [Accepted: 01/07/2014] [Indexed: 11/24/2022]
Abstract
A biological molecule, e.g., an enzyme, tends to interact with its many cognate substrates, targets, or partners differentially. Such a property is termed relative specificity and has been proposed to regulate important physiological functions, even though it has not been examined explicitly in most complex biochemical systems. This essay reviews several recent large-scale studies that investigate protein folding, signal transduction, RNA binding, translation and transcription in the context of relative specificity. These results and others support a pervasive role of relative specificity in diverse biological processes. It is becoming clear that relative specificity contributes fundamentally to the diversity and complexity of biological systems, which has significant implications in disease processes as well.
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20
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Ge XH, Ding L, Li ZY. Nucleolar dominance and different genome behaviors in hybrids and allopolyploids. PLANT CELL REPORTS 2013; 32:1661-73. [PMID: 23864197 DOI: 10.1007/s00299-013-1475-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 07/01/2013] [Indexed: 05/05/2023]
Abstract
Many plants are allopolyploids with different nuclear genomes from two or more progenitors, but cytoplasmic genomes typically inherited from the female parent. The importance of this speciation mechanism has stimulated the extensive investigations of genetic consequences of genome mergers in several experimental systems during last 20 years. The dynamic nature of polyploid genomes is recognized, and widespread changes to gene expression are revealed by transcriptomic analysis. These progresses show different stabilities of parental genomes and their unequal contributions to the transcriptome, proteome, and phenotype. We review the results in systems where extensive genetic analyses have been conducted and propose possible mechanisms for biased behavior of parental genomes in allopolyploids, including the role of nucleolar dominance. It is hypothesized that the novel ribosomes with rRNAs from uniparental genome and the ribosomal proteins of biparental origins have some impacts on the biased cellular and genetic behaviors of parental genomes in hybrids and allopolyploids.
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Affiliation(s)
- Xian-Hong Ge
- National Key Lab of Crop Genetic Improvement, College of Plant Science and Technology, National Center of Crop Molecular Breeding, National Center of Oil Crop Improvement (Wuhan), Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
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21
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Shukla SK, Kumar V. Hepatitis B virus X protein and c-Myc cooperate in the upregulation of ribosome biogenesis and in cellular transformation. FEBS J 2012; 279:3859-71. [PMID: 22889122 DOI: 10.1111/j.1742-4658.2012.08745.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 07/24/2012] [Accepted: 08/09/2012] [Indexed: 12/19/2022]
Abstract
Viral and cellular oncogenes are well known to enhance rRNA synthesis, leading to increased ribosome biogenesis and cell proliferation. Our study on the molecular underpinnings of the interaction between viral HBx and c-Myc, which is implicated in the development of hepatocellular carcinoma, showed a marked increase in the biosynthesis of rRNA, ribosomes and protein in hepatoma cells. A profound alteration in the nucleolar morphology and biochemical content of these cells was also observed. Increased biosynthetic activity was associated with increased cell proliferation and transformation of immortalized human hepatocytes. Furthermore, inhibition of RNA polymerase III activity impaired the proliferative advantage of hepatoma cells and transformation of immortalized hepatocytes as effectively as cisplatin treatment. These findings were corroborated in a transgenic HBx-myc microenvironment, in which an elevated hepatic level of rRNA was associated with conspicuous morphological and biochemical changes in the hepatocytic nucleoli. Thus, HBx and c-Myc seem to work cooperatively to support ribosome biogenesis and cellular transformation.
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22
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Sousounis K, Tsonis PA. Patterns of gene expression in microarrays and expressed sequence tags from normal and cataractous lenses. Hum Genomics 2012; 6:14. [PMID: 23244575 PMCID: PMC3563465 DOI: 10.1186/1479-7364-6-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 05/14/2012] [Indexed: 11/30/2022] Open
Abstract
In this contribution, we have examined the patterns of gene expression in normal and cataractous lenses as presented in five different papers using microarrays and expressed sequence tags. The purpose was to evaluate unique and common patterns of gene expression during development, aging and cataracts.
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Affiliation(s)
- Konstantinos Sousounis
- Department of Biology and Center for Tissue Regeneration and Engineering, University of Dayton, Dayton, OH 45469-2320, USA
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23
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Attenuation of 40S ribosomal subunit abundance differentially affects host and HCV translation and suppresses HCV replication. PLoS Pathog 2012; 8:e1002766. [PMID: 22792060 PMCID: PMC3394201 DOI: 10.1371/journal.ppat.1002766] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 05/07/2012] [Indexed: 01/13/2023] Open
Abstract
For Hepatitis C virus (HCV), initiation of translation is cap-independently mediated by its internal ribosome entry site (IRES). Unlike other IRES-containing viruses that shut off host cap-dependent translation, translation of HCV coexists with that of the host. How HCV IRES-mediated translation is regulated in the infected cells remains unclear. Here, we show that the intracellular level of 40S ribosomal subunit plays a key role in facilitating HCV translation over host translation. In a loss-of-function screen, we identified small subunit ribosomal protein 6 (RPS6) as an indispensable host factor for HCV propagation. Knockdown of RPS6 selectively repressed HCV IRES-mediated translation, but not general translation. Such preferential suppression of HCV translation correlated well with the reduction of the abundance of 40S ribosomal subunit following knockdown of RPS6 or other RPS genes. In contrast, reduction of the amount of ribosomal proteins of the 60S subunit did not produce similar effects. Among the components of general translation machineries, only knockdowns of RPS genes caused inhibitory effects on HCV translation, pointing out the unique role of 40S subunit abundance in HCV translation. This work demonstrates an unconventional notion that the translation initiation of HCV and host possess different susceptibility toward reduction of 40S ribosomal subunit, and provides a model of selective modulation of IRES-mediated translation through manipulating the level of 40S subunit.
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24
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Fromm-Dornieden C, von der Heyde S, Lytovchenko O, Salinas-Riester G, Brenig B, Beissbarth T, Baumgartner BG. Novel polysome messages and changes in translational activity appear after induction of adipogenesis in 3T3-L1 cells. BMC Mol Biol 2012; 13:9. [PMID: 22436005 PMCID: PMC3347988 DOI: 10.1186/1471-2199-13-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 03/21/2012] [Indexed: 01/06/2023] Open
Abstract
Background Control of translation allows for rapid adaptation of the cell to stimuli, rather than the slower transcriptional control. We presume that translational control is an essential process in the control of adipogenesis, especially in the first hours after hormonal stimulation. 3T3-L1 preadipocytes were cultured to confluency and adipogenesis was induced by standard protocols using a hormonal cocktail. Cells were harvested before and 6 hours after hormonal induction. mRNAs attached to ribosomes (polysomal mRNAs) were separated from unbound mRNAs by velocity sedimentation. Pools of polysomal and unbound mRNA fractions were analyzed by microarray analysis. Changes in relative abundance in unbound and polysomal mRNA pools were calculated to detect putative changes in translational activity. Changes of expression levels of selected genes were verified by qPCR and Western blotting. Results We identified 43 genes that shifted towards the polysomal fraction (up-regulated) and 2 genes that shifted towards free mRNA fraction (down-regulated). Interestingly, we found Ghrelin to be down-regulated. Up-regulated genes comprise factors that are nucleic acid binding (eIF4B, HSF1, IRF6, MYC, POLR2a, RPL18, RPL27a, RPL6, RPL7a, RPS18, RPSa, TSC22d3), form part of ribosomes (RPL18, RPL27a, RPL6, RPL7a, RPS18, RPSa), act on the regulation of translation (eIF4B) or transcription (HSF1, IRF6, MYC, TSC22d3). Others act as chaperones (BAG3, HSPA8, HSP90ab1) or in other metabolic or signals transducing processes. Conclusions We conclude that a moderate reorganisation of the functionality of the ribosomal machinery and translational activity are very important steps for growth and gene expression control in the initial phase of adipogenesis.
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25
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Zeng Y. The functional consequences of relative substrate specificity in complex biochemical systems. Front Genet 2011; 2:65. [PMID: 22303360 PMCID: PMC3268618 DOI: 10.3389/fgene.2011.00065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Accepted: 08/30/2011] [Indexed: 11/13/2022] Open
Abstract
A biochemical activity, that is, enzymatic reaction or molecular interaction, frequently involves a molecule, for example, an enzyme, capable of interacting with numerous substrates or partners. Specificity is a fundamental property of biochemical activities, and relative specificity refers to the situation whereby a molecule interacts with multiple substrates or partners but with different affinities. Here, a hypothesis is proposed that any molecule, such as an enzyme, would have a range of preferences or relative specificity for its many native substrates, which differentially impacts the phenotypes of these substrates and hence shapes the relevant biological processes in vivo. While the mechanisms underlying the specific recognition between enzymes and individual substrates have been studied extensively, whether any enzyme exhibits intrinsic selectivity toward its ensemble of substrates is often overlooked, and whether this selectivity has any functional consequences is much less appreciated. There are, however, several lines of evidence in the literature that are consistent with the hypothesis and reviewed here. Furthermore, this hypothesis is supported by our analyses of a number of diverse biochemical systems at a large scale. Thus, the human microRNA processing machinery possesses relative specificity toward its hundreds of substrates, which might contribute to differential microRNA biogenesis; the promoter binding affinity of the transcription factor Ndt80 might regulate Ndt80 target mRNA expression in the budding yeast; Cdk1 kinase specificity might lead to variable substrate phosphorylation in vivo; and the density of HuR deposition to its thousands of RNA targets might partly explain differential RNA expression in human cells. It is proposed, therefore, that relative specificity is a universal property of complex biochemical systems and that the hypothesis could denote a general principle in biology.
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Affiliation(s)
- Yan Zeng
- Department of Pharmacology, Masonic Cancer Center, University of Minnesota Minneapolis, MN, USA
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