1
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Kurpiejewski K, Piecyk K, Lukaszewicz M, Kamel K, Chmurski K, Kmiecik S, Jankowska-Anyszka M. The Synergistic Effect of N2 and N7 Modifications on the Inhibitory Efficacy of mRNA Cap Analogues. Pharmaceuticals (Basel) 2024; 17:632. [PMID: 38794202 PMCID: PMC11123931 DOI: 10.3390/ph17050632] [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: 04/08/2024] [Revised: 04/30/2024] [Accepted: 05/02/2024] [Indexed: 05/26/2024] Open
Abstract
In the fight against cancer, researchers have turned their attention to the eukaryotic initiation factor eIF4E, a protein whose increased level is strongly correlated with the development and progression of various types of cancer. Among the numerous strategies devised to tackle eIF4E overexpression, the use of 5' end mRNA cap analogues has emerged as a promising approach. Here, we present new candidates as potent m7GMP analogues for inhibiting translation and interfacing with eIF4E. By employing an appropriate strategy, we synthesized doubly modified mono- and dinucleotide cap analogues, introducing simultaneous substituents at both the N7 and N2 positions of the guanine ring. This approach was identified as an effective and promising combination. Our findings reveal that these dual modifications increase the potency of the dinucleotide analogue, marking a significant advancement in the development of cancer therapeutics targeting the eIF4E pathway.
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Affiliation(s)
- Karol Kurpiejewski
- Faculty of Chemistry, University of Warsaw, 02-093 Warsaw, Poland; (K.K.); (K.P.); (K.C.)
| | - Karolina Piecyk
- Faculty of Chemistry, University of Warsaw, 02-093 Warsaw, Poland; (K.K.); (K.P.); (K.C.)
| | - Maciej Lukaszewicz
- Division of Biophysics, Institute of Experimental Physics, University of Warsaw, 02-093 Warsaw, Poland;
| | - Karol Kamel
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704 Poznan, Poland;
| | - Kazimierz Chmurski
- Faculty of Chemistry, University of Warsaw, 02-093 Warsaw, Poland; (K.K.); (K.P.); (K.C.)
| | - Sebastian Kmiecik
- Biological and Chemical Research Centre, Faculty of Chemistry, University of Warsaw, 02-089 Warsaw, Poland;
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2
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Jiao D, Sun H, Zhao X, Chen Y, Lv Z, Shi Q, Li Y, Wang C, Gao K. mTORC1/S6K1 signaling promotes sustained oncogenic translation through modulating CRL3 IBTK-mediated ubiquitination of eIF4A1 in cancer cells. eLife 2024; 12:RP92236. [PMID: 38738857 PMCID: PMC11090508 DOI: 10.7554/elife.92236] [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] [Indexed: 05/14/2024] Open
Abstract
Enhanced protein synthesis is a crucial molecular mechanism that allows cancer cells to survive, proliferate, metastasize, and develop resistance to anti-cancer treatments, and often arises as a consequence of increased signaling flux channeled to mRNA-bearing eukaryotic initiation factor 4F (eIF4F). However, the post-translational regulation of eIF4A1, an ATP-dependent RNA helicase and subunit of the eIF4F complex, is still poorly understood. Here, we demonstrate that IBTK, a substrate-binding adaptor of the Cullin 3-RING ubiquitin ligase (CRL3) complex, interacts with eIF4A1. The non-degradative ubiquitination of eIF4A1 catalyzed by the CRL3IBTK complex promotes cap-dependent translational initiation, nascent protein synthesis, oncogene expression, and cervical tumor cell growth both in vivo and in vitro. Moreover, we show that mTORC1 and S6K1, two key regulators of protein synthesis, directly phosphorylate IBTK to augment eIF4A1 ubiquitination and sustained oncogenic translation. This link between the CRL3IBTK complex and the mTORC1/S6K1 signaling pathway, which is frequently dysregulated in cancer, represents a promising target for anti-cancer therapies.
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Affiliation(s)
- Dongyue Jiao
- State Key Laboratory of Genetic Engineering, Shanghai Stomatological Hospital & School of Stomatology, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan UniversityShanghaiChina
| | - Huiru Sun
- State Key Laboratory of Genetic Engineering, Shanghai Stomatological Hospital & School of Stomatology, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan UniversityShanghaiChina
| | - Xiaying Zhao
- State Key Laboratory of Genetic Engineering, Shanghai Stomatological Hospital & School of Stomatology, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan UniversityShanghaiChina
| | - Yingji Chen
- State Key Laboratory of Genetic Engineering, Shanghai Stomatological Hospital & School of Stomatology, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan UniversityShanghaiChina
| | - Zeheng Lv
- Department of Clinical Laboratory, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji UniversityShanghaiChina
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji UniversityShanghaiChina
| | - Qing Shi
- State Key Laboratory of Genetic Engineering, Shanghai Stomatological Hospital & School of Stomatology, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan UniversityShanghaiChina
| | - Yao Li
- State Key Laboratory of Genetic Engineering, Shanghai Stomatological Hospital & School of Stomatology, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan UniversityShanghaiChina
| | - Chenji Wang
- State Key Laboratory of Genetic Engineering, Shanghai Stomatological Hospital & School of Stomatology, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan UniversityShanghaiChina
| | - Kun Gao
- Department of Clinical Laboratory, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji UniversityShanghaiChina
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji UniversityShanghaiChina
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3
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Mir DA, Ma Z, Horrocks J, Rogers AN. Stress-induced Eukaryotic Translational Regulatory Mechanisms. ARXIV 2024:arXiv:2405.01664v1. [PMID: 38745702 PMCID: PMC11092689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
The eukaryotic protein synthesis process entails intricate stages governed by diverse mechanisms to tightly regulate translation. Translational regulation during stress is pivotal for maintaining cellular homeostasis, ensuring the accurate expression of essential proteins crucial for survival. This selective translational control mechanism is integral to cellular adaptation and resilience under adverse conditions. This review manuscript explores various mechanisms involved in selective translational regulation, focusing on mRNA-specific and global regulatory processes. Key aspects of translational control include translation initiation, which is often a rate-limiting step, and involves the formation of the eIF4F complex and recruitment of mRNA to ribosomes. Regulation of translation initiation factors, such as eIF4E, eIF4E2, and eIF2, through phosphorylation and interactions with binding proteins, modulates translation efficiency under stress conditions. This review also highlights the control of translation initiation through factors like the eIF4F complex and the ternary complex and also underscores the importance of eIF2α phosphorylation in stress granule formation and cellular stress responses. Additionally, the impact of amino acid deprivation, mTOR signaling, and ribosome biogenesis on translation regulation and cellular adaptation to stress is also discussed. Understanding the intricate mechanisms of translational regulation during stress provides insights into cellular adaptation mechanisms and potential therapeutic targets for various diseases, offering valuable avenues for addressing conditions associated with dysregulated protein synthesis.
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Affiliation(s)
- Dilawar Ahmad Mir
- Kathryn W. Davis Center for Regenerative Biology and Aging, Mount Desert Island Biological Laboratory, Bar Harbor, ME
| | - Zhengxin Ma
- Kathryn W. Davis Center for Regenerative Biology and Aging, Mount Desert Island Biological Laboratory, Bar Harbor, ME
| | - Jordan Horrocks
- Kathryn W. Davis Center for Regenerative Biology and Aging, Mount Desert Island Biological Laboratory, Bar Harbor, ME
| | - Aric N Rogers
- Kathryn W. Davis Center for Regenerative Biology and Aging, Mount Desert Island Biological Laboratory, Bar Harbor, ME
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4
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Villa N, Fraser CS. Human eukaryotic initiation factor 4G directly binds the 40S ribosomal subunit to promote efficient translation. J Biol Chem 2024; 300:107242. [PMID: 38569933 PMCID: PMC11063902 DOI: 10.1016/j.jbc.2024.107242] [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: 09/30/2023] [Revised: 03/15/2024] [Accepted: 03/19/2024] [Indexed: 04/05/2024] Open
Abstract
Messenger RNA (mRNA) recruitment to the 40S ribosomal subunit is mediated by eukaryotic initiation factor 4F (eIF4F). This complex includes three subunits: eIF4E (m7G cap-binding protein), eIF4A (DEAD-box helicase), and eIF4G. Mammalian eIF4G is a scaffold that coordinates the activities of eIF4E and eIF4A and provides a bridge to connect the mRNA and 40S ribosomal subunit through its interaction with eIF3. While the roles of many eIF4G binding domains are relatively clear, the precise function of RNA binding by eIF4G remains to be elucidated. In this work, we used an eIF4G-dependent translation assay to reveal that the RNA binding domain (eIF4G-RBD; amino acids 682-720) stimulates translation. This stimulating activity is observed when eIF4G is independently tethered to an internal region of the mRNA, suggesting that the eIF4G-RBD promotes translation by a mechanism that is independent of the m7G cap and mRNA tethering. Using a kinetic helicase assay, we show that the eIF4G-RBD has a minimal effect on eIF4A helicase activity, demonstrating that the eIF4G-RBD is not required to coordinate eIF4F-dependent duplex unwinding. Unexpectedly, native gel electrophoresis and fluorescence polarization assays reveal a previously unidentified direct interaction between eIF4G and the 40S subunit. Using binding assays, our data show that this 40S subunit interaction is separate from the previously characterized interaction between eIF4G and eIF3. Thus, our work reveals how eIF4F can bind to the 40S subunit using eIF3-dependent and eIF3-independent binding domains to promote translation initiation.
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Affiliation(s)
- Nancy Villa
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, California, USA
| | - Christopher S Fraser
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, California, USA.
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5
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Zeng J, Lu C, Huang X, Li Y. The human eIF4E:4E-BP2 complex structure for studying hyperphosphorylation. Phys Chem Chem Phys 2024; 26:10660-10672. [PMID: 38511550 DOI: 10.1039/d3cp05736d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
The cap-dependent mRNA translation is dysregulated in many kinds of cancers. The interaction between eIF4E and eIF4G through a canonical eIF4E-binding motif (CEBM) determines the efficacy of the cap-dependent mRNA translation. eIF4E-binding proteins (4E-BPs) share the CEBM and compete with eIF4G for the same binding surface of eIF4E and then inhibit the mRNA translation. 4E-BPs function as tumor repressors in nature. Hyperphosphorylation of 4E-BPs regulates the structure folding and causes the dissociation of 4E-BPs from eIF4E. However, until now, there has been no structure of the full-length 4E-BPs in complex with eIF4E. The regulation mechanism of phosphorylation is still unclear. In this work, we first investigate the interactions of human eIF4E with the CEBM and an auxiliary eIF4E-binding motif (AEBM) in eIF4G and 4E-BPs. The results unravel that the structure and interactions of the CEBM are highly conserved between eIF4G and 4E-BPs. However, the extended CEBM (ECEBM) in 4E-BPs forms a longer helix than that in eIF4G. The residue R62 in the ECEBM of 4E-BP2 forms salt bridges with E32 and E70 of eIF4E. The residue R63 of 4E-BP2 forms two special hydrogen bonds with N77 of eIF4E. Both of these interactions are missing in eIF4G. The AEBM of 4E-BPs folds into a β-sheet conformation, which protects V81 inside a hydrophobic core in 4E-BP2. In eIF4G, the AEBM exists in a random coil state. The hydrophilic residues S637 and D638 of eIF4G open the hydrophobic core for solvents. The results show that the ECEBM and AEBM may be responsible for the competing advantage of 4E-BP2. Finally, based on our previous work (J. Zeng, F. Jiang and Y. D. Wu, J. Chem. Theory Comput., 2017, 13, 320), the human eIF4E:4E-BP2 complex (eIF4E:BP2P18-I88) including all reported phosphorylation sites is predicted. The eIF4E:BP2P18-I88 complex is different from the existing experimental eIF4E:eIF4G complex and provides an important structure for further studying the regulation mechanism of phosphorylation in 4E-BPs.
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Affiliation(s)
- Juan Zeng
- School of Biomedical Engineering, Guangdong Medical University, Dongguan 523808, China.
| | - CuiMin Lu
- School of Biomedical Engineering, Guangdong Medical University, Dongguan 523808, China.
| | - Xuan Huang
- School of Biomedical Engineering, Guangdong Medical University, Dongguan 523808, China.
| | - Yang Li
- Department of Urology, Huaihe Hospital of Henan University, Kaifeng 475000, Henan, China.
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Liao T, Chen Y, Guo L, Zhu S, Zhan T, Lu X, Xu H, Hu Z, Hu J, Gu M, Liu X, Wang X, Hu S, Liu X. The NP protein of Newcastle disease virus dictates its oncolytic activity by regulating viral mRNA translation efficiency. PLoS Pathog 2024; 20:e1012027. [PMID: 38377149 PMCID: PMC10906838 DOI: 10.1371/journal.ppat.1012027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 03/01/2024] [Accepted: 02/05/2024] [Indexed: 02/22/2024] Open
Abstract
Newcastle disease virus (NDV) has been extensively studied as a promising oncolytic virus for killing tumor cells in vitro and in vivo in clinical trials. However, the viral components that regulate the oncolytic activity of NDV remain incompletely understood. In this study, we systematically compared the replication ability of different NDV genotypes in various tumor cells and identified NP protein determines the oncolytic activity of NDV. On the one hand, NDV strains with phenylalanine (F) at the 450th amino acid position of the NP protein (450th-F-NP) exhibit a loss of oncolytic activity. This phenotype is predominantly associated with genotype VII NDVs. In contrast, the NP protein with a leucine amino acid at this site in other genotypes (450th-L-NP) can facilitate the loading of viral mRNA onto ribosomes more effectively than 450th-F-NP. On the other hand, the NP protein from NDV strains that exhibit strong oncogenicity interacts with eIF4A1 within its 366-489 amino acid region, leading to the inhibition of cellular mRNA translation with a complex 5' UTR structure. Our study provide mechanistic insights into how highly oncolytic NDV strains selectively promote the translation of viral mRNA and will also facilitate the screening of oncolytic strains for oncolytic therapy.
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Affiliation(s)
- Tianxing Liao
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Yu Chen
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Lili Guo
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Shanshan Zhu
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Tiansong Zhan
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Xiaolong Lu
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Haixu Xu
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Zenglei Hu
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infections Diseases and Zoonoses, Yangzhou University, Yangzhou, China
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Jiao Hu
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infections Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Min Gu
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
| | - Xiaowen Liu
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infections Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Xiaoquan Wang
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Shunlin Hu
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infections Diseases and Zoonoses, Yangzhou University, Yangzhou, China
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
| | - Xiufan Liu
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infections Diseases and Zoonoses, Yangzhou University, Yangzhou, China
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Ministry of Education of China, Yangzhou University, Yangzhou, China
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7
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Eliseeva IA, Buyan AI, Smolin EA, Kaliadzenka KS, Popov S, Kulakovskiy IV, Lyabin DN. Y-Box-Binding Proteins Have a Dual Impact on Cellular Translation. Int J Mol Sci 2024; 25:1736. [PMID: 38339016 PMCID: PMC10855678 DOI: 10.3390/ijms25031736] [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: 12/19/2023] [Revised: 01/24/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024] Open
Abstract
Y-box-binding proteins (YB proteins) are multifunctional DNA- and RNA-binding proteins that play an important role in the regulation of gene expression. The high homology of their cold shock domains and the similarity between their long, unstructured C-terminal domains suggest that Y-box-binding proteins may have similar functions in a cell. Here, we consider the functional interchangeability of the somatic YB proteins YB-1 and YB-3. RNA-seq and Ribo-seq are used to track changes in the mRNA abundance or mRNA translation in HEK293T cells solely expressing YB-1, YB-3, or neither of them. We show that YB proteins have a dual effect on translation. Although the expression of YB proteins stimulates global translation, YB-1 and YB-3 inhibit the translation of their direct CLIP-identified mRNA targets. The impact of YB-1 and YB-3 on the translation of their mRNA targets is similar, which suggests that they can substitute each other in inhibiting the translation of their mRNA targets in HEK293T cells.
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Affiliation(s)
- Irina A. Eliseeva
- Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Russia; (I.A.E.); (A.I.B.); (E.A.S.); (K.S.K.); (I.V.K.)
| | - Andrey I. Buyan
- Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Russia; (I.A.E.); (A.I.B.); (E.A.S.); (K.S.K.); (I.V.K.)
| | - Egor A. Smolin
- Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Russia; (I.A.E.); (A.I.B.); (E.A.S.); (K.S.K.); (I.V.K.)
| | - Karina S. Kaliadzenka
- Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Russia; (I.A.E.); (A.I.B.); (E.A.S.); (K.S.K.); (I.V.K.)
| | - Sergey Popov
- Endocrinology Research Center, Moscow 117036, Russia;
| | - Ivan V. Kulakovskiy
- Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Russia; (I.A.E.); (A.I.B.); (E.A.S.); (K.S.K.); (I.V.K.)
| | - Dmitry N. Lyabin
- Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Russia; (I.A.E.); (A.I.B.); (E.A.S.); (K.S.K.); (I.V.K.)
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8
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Penteado RF, da Silva RS, Moura DMN, de Lima GB, Malvezzi AM, Monteiro TTDS, Xavier CC, Vichier-Guerre S, Dugué L, Pochet S, Zanchin NIT, Reis CRDS, de Melo Neto OP, Guimarães BG. Structural analysis of the Trypanosoma brucei EIF4E6/EIF4G5 complex reveals details of the interaction between unusual eIF4F subunits. Sci Rep 2024; 14:2178. [PMID: 38272944 PMCID: PMC10810786 DOI: 10.1038/s41598-024-52364-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 01/17/2024] [Indexed: 01/27/2024] Open
Abstract
Recognition of the mRNA 5' end is a critical step needed for translation initiation. This step is performed by the cap binding protein eIF4E, which joins the larger eIF4G subunit to form the eIF4F complex. Trypanosomatids have a minimum of five different eIF4F-like complexes formed through specific but not well-defined interactions between four different eIF4E and five eIF4G homologues. The EIF4E6/EIF4G5 complex has been linked with the stage-specific translation of mRNAs encoding the major Trypanosoma brucei virulence factors. Here, to better define the molecular basis for the TbEIF4E6/TbEIF4G5 interaction, we describe the identification of the peptide interacting with TbEIF4E6 in the region comprising residues 79-166 of TbEIF4G5. The TbEIF4E6-TbEIF4G5_79-116 complex reconstituted with recombinant proteins is highly stable even in the absence of cap-4. The crystal structure of the complex was subsequently solved, revealing extensive interacting surfaces. Comparative analyses highlight the conservation of the overall structural arrangement of different eIF4E/eIF4G complexes. However, highly different interacting surfaces are formed with distinct binding contacts occurring both in the canonical and noncanonical elements within eIF4G and the respective eIF4E counterpart. These specific pairs of complementary interacting surfaces are likely responsible for the selective association needed for the formation of distinct eIF4F complexes in trypanosomatids.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Laurence Dugué
- Epigenetic Chemical Biology, Institut Pasteur, Paris, France
| | - Sylvie Pochet
- Epigenetic Chemical Biology, Institut Pasteur, Paris, France
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9
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Mondal S, Rousseau S, Talenton V, Thiam CAB, Aznauryan M, Mackereth CD. Backbone resonance assignments of the C-terminal region of human translation initiation factor eIF4B. BIOMOLECULAR NMR ASSIGNMENTS 2023; 17:199-203. [PMID: 37368134 DOI: 10.1007/s12104-023-10141-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 06/21/2023] [Indexed: 06/28/2023]
Abstract
Translation initiation in eukaryotes is an early step in protein synthesis, requiring multiple factors to recruit the ribosomal small subunit to the mRNA 5' untranslated region. One such protein factor is the eukaryotic translation initiation factor 4B (eIF4B), which increases the activity of the eIF4A RNA helicase, and is linked to cell survival and proliferation. We report here the protein backbone chemical shift assignments corresponding to the C-terminal 279 residues of human eIF4B. Analysis of the chemical shift values identifies one main helical region in the area previously linked to RNA binding, and confirms that the overall C-terminal region is intrinsically disordered.
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Affiliation(s)
- Somnath Mondal
- Univ. Bordeaux, Inserm U1212, CNRS UMR 5320, Institut Européen de Chimie et Biologie, Pessac, F-33600, France
| | - Sabrina Rousseau
- Univ. Bordeaux, Inserm U1212, CNRS UMR 5320, Institut Européen de Chimie et Biologie, Pessac, F-33600, France
| | - Vincent Talenton
- Univ. Bordeaux, Inserm U1212, CNRS UMR 5320, Institut Européen de Chimie et Biologie, Pessac, F-33600, France
| | - Cheikh Ahmadou Bamba Thiam
- Univ. Bordeaux, Inserm U1212, CNRS UMR 5320, Institut Européen de Chimie et Biologie, Pessac, F-33600, France
| | - Mikayel Aznauryan
- Univ. Bordeaux, Inserm U1212, CNRS UMR 5320, Institut Européen de Chimie et Biologie, Pessac, F-33600, France.
| | - Cameron D Mackereth
- Univ. Bordeaux, Inserm U1212, CNRS UMR 5320, Institut Européen de Chimie et Biologie, Pessac, F-33600, France.
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10
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Gentry RC, Ide NA, Comunale VM, Hartwick EW, Kinz-Thompson CD, Gonzalez RL. The mechanism of mRNA activation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.15.567265. [PMID: 38014128 PMCID: PMC10680758 DOI: 10.1101/2023.11.15.567265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
During translation initiation, messenger RNA molecules must be identified and activated for loading into a ribosome. In this rate-limiting step, the heterotrimeric protein eukaryotic initiation factor eIF4F must recognize and productively interact with the 7-methylguanosine cap at the 5' end of the messenger RNA and subsequently activate the message. Despite its fundamental, regulatory role in gene expression, the molecular events underlying cap recognition and messenger RNA activation remain mysterious. Here, we generate a unique, single-molecule fluorescence imaging system to interrogate the dynamics with which eIF4F discriminates productive and non-productive locations on full-length, native messenger RNA molecules. At the single-molecule level, we observe stochastic sampling of eIF4F along the length of the messenger RNA and identify allosteric communication between the eIF4F subunits which ultimately drive cap-recognition and subsequent activation of the message. Our experiments uncover novel functions for each subunit of eIF4F and we conclude by presenting a model for messenger RNA activation which precisely defines the composition of the activated message. This model provides a general framework for understanding how messenger RNA molecules may be discriminated from one another, and how other RNA-binding proteins may control the efficiency of translation initiation.
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Affiliation(s)
- Riley C Gentry
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Nicholas A Ide
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | | | - Erik W Hartwick
- Department of Chemistry, Columbia University, New York, NY, USA
- Current Address: BioChemistry Krios Electron Microscopy Facility, Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Colin D Kinz-Thompson
- Department of Chemistry, Columbia University, New York, NY, USA
- Current Address: Department of Chemistry, Rutgers University-Newark, Newark, NJ 07102
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11
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Kershaw CJ, Nelson MG, Castelli LM, Jennings MD, Lui J, Talavera D, Grant CM, Pavitt GD, Hubbard SJ, Ashe MP. Translation factor and RNA binding protein mRNA interactomes support broader RNA regulons for posttranscriptional control. J Biol Chem 2023; 299:105195. [PMID: 37633333 PMCID: PMC10562868 DOI: 10.1016/j.jbc.2023.105195] [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: 07/07/2023] [Revised: 08/18/2023] [Accepted: 08/20/2023] [Indexed: 08/28/2023] Open
Abstract
The regulation of translation provides a rapid and direct mechanism to modulate the cellular proteome. In eukaryotes, an established model for the recruitment of ribosomes to mRNA depends upon a set of conserved translation initiation factors. Nevertheless, how cells orchestrate and define the selection of individual mRNAs for translation, as opposed to other potential cytosolic fates, is poorly understood. We have previously found significant variation in the interaction between individual mRNAs and an array of translation initiation factors. Indeed, mRNAs can be separated into different classes based upon these interactions to provide a framework for understanding different modes of translation initiation. Here, we extend this approach to include new mRNA interaction profiles for additional proteins involved in shaping the cytoplasmic fate of mRNAs. This work defines a set of seven mRNA clusters, based on their interaction profiles with 12 factors involved in translation and/or RNA binding. The mRNA clusters share both physical and functional characteristics to provide a rationale for the interaction profiles. Moreover, a comparison with mRNA interaction profiles from a host of RNA binding proteins suggests that there are defined patterns in the interactions of functionally related mRNAs. Therefore, this work defines global cytoplasmic mRNA binding modules that likely coordinate the synthesis of functionally related proteins.
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Affiliation(s)
- Christopher J Kershaw
- Division of Molecular and Cellular Function, School of Biological Sciences, The University of Manchester, Manchester, UK
| | - Michael G Nelson
- Division of Molecular and Cellular Function, School of Biological Sciences, The University of Manchester, Manchester, UK
| | - Lydia M Castelli
- Division of Molecular and Cellular Function, School of Biological Sciences, The University of Manchester, Manchester, UK
| | - Martin D Jennings
- Division of Molecular and Cellular Function, School of Biological Sciences, The University of Manchester, Manchester, UK
| | - Jennifer Lui
- Division of Molecular and Cellular Function, School of Biological Sciences, The University of Manchester, Manchester, UK
| | - David Talavera
- Division of Cardiovascular Sciences, School of Medical Sciences, The University of Manchester, Manchester, UK
| | - Chris M Grant
- Division of Molecular and Cellular Function, School of Biological Sciences, The University of Manchester, Manchester, UK
| | - Graham D Pavitt
- Division of Molecular and Cellular Function, School of Biological Sciences, The University of Manchester, Manchester, UK.
| | - Simon J Hubbard
- Division of Molecular and Cellular Function, School of Biological Sciences, The University of Manchester, Manchester, UK.
| | - Mark P Ashe
- Division of Molecular and Cellular Function, School of Biological Sciences, The University of Manchester, Manchester, UK.
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12
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Bohnsack KE, Yi S, Venus S, Jankowsky E, Bohnsack MT. Cellular functions of eukaryotic RNA helicases and their links to human diseases. Nat Rev Mol Cell Biol 2023; 24:749-769. [PMID: 37474727 DOI: 10.1038/s41580-023-00628-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2023] [Indexed: 07/22/2023]
Abstract
RNA helicases are highly conserved proteins that use nucleoside triphosphates to bind or remodel RNA, RNA-protein complexes or both. RNA helicases are classified into the DEAD-box, DEAH/RHA, Ski2-like, Upf1-like and RIG-I families, and are the largest class of enzymes active in eukaryotic RNA metabolism - virtually all aspects of gene expression and its regulation involve RNA helicases. Mutation and dysregulation of these enzymes have been linked to a multitude of diseases, including cancer and neurological disorders. In this Review, we discuss the regulation and functional mechanisms of RNA helicases and their roles in eukaryotic RNA metabolism, including in transcription regulation, pre-mRNA splicing, ribosome assembly, translation and RNA decay. We highlight intriguing models that link helicase structure, mechanisms of function (such as local strand unwinding, translocation, winching, RNA clamping and displacing RNA-binding proteins) and biological roles, including emerging connections between RNA helicases and cellular condensates formed through liquid-liquid phase separation. We also discuss associations of RNA helicases with human diseases and recent efforts towards the design of small-molecule inhibitors of these pivotal regulators of eukaryotic gene expression.
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Affiliation(s)
- Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany.
| | - Soon Yi
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Sarah Venus
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Eckhard Jankowsky
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
- Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
- Moderna, Cambridge, MA, USA.
| | - Markus T Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany.
- Göttingen Centre for Molecular Biosciences, University of Göttingen, Göttingen, Germany.
- Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
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13
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Zuberek J, Warzecha M, Dobrowolski M, Modrak-Wojcik A. An intramolecular disulphide bond in human 4E-T affects its binding to eIF4E1a protein. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2023; 52:497-510. [PMID: 37798395 PMCID: PMC10618305 DOI: 10.1007/s00249-023-01684-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 09/14/2023] [Accepted: 09/16/2023] [Indexed: 10/07/2023]
Abstract
The cap at the 5'terminus of mRNA is a key determinant of gene expression in eukaryotic cells, which among others is required for cap dependent translation and protects mRNA from degradation. These properties of cap are mediated by several proteins. One of them is 4E-Transporter (4E-T), which plays an important role in translational repression, mRNA decay and P-bodies formation. 4E-T is also one of several proteins that interact with eukaryotic initiation factor 4E (eIF4E), a cap binding protein which is a key component of the translation initiation machinery. The molecular mechanisms underlying the interactions of these two proteins are crucial for mRNA processing. Studying the interactions between human eIF4E1a and the N-terminal fragment of 4E-T that possesses unstructured 4E-binding motifs under non-reducing conditions, we observed that 4E-T preferentially forms an intramolecular disulphide bond. This "disulphide loop" reduces affinity of 4E-T for eIF4E1a by about 300-fold. Considering that only human 4E-T possesses two cysteines located between the 4E binding motifs, we proposed that the disulphide bond may act as a switch to regulate interactions between the two proteins.
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Affiliation(s)
- Joanna Zuberek
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland.
| | - Marek Warzecha
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland
| | - Mateusz Dobrowolski
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland
| | - Anna Modrak-Wojcik
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland
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14
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Villa N, Fraser CS. Human eukaryotic initiation factor 4G directly binds the 40S ribosomal subunit to promote efficient translation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.29.560218. [PMID: 37808713 PMCID: PMC10557762 DOI: 10.1101/2023.09.29.560218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Messenger RNA (mRNA) recruitment to the 40S ribosomal subunit is mediated by eukaryotic initiation factor 4F (eIF4F). This complex includes 3 subunits: eIF4E (m 7 G cap binding protein), eIF4A (DEAD box helicase), and eIF4G. Mammalian eIF4G is a scaffold that coordinates the activities of eIF4E and eIF4A and provides a bridge to connect the mRNA and 40S ribosomal subunit through its interaction with eIF3. While the roles of many eIF4G binding domains are relatively clear, the precise function of RNA binding by eIF4G remains to be elucidated. In this work, we used an eIF4G-dependent translation assay to reveal that the RNA binding domain (eIF4G-RBD; amino acids 682-720) stimulates translation. This stimulating activity is observed when eIF4G is independently tethered to an internal region of the mRNA, suggesting that the eIF4G-RBD promotes translation by a mechanism that is independent of the m 7 G cap and mRNA tethering. Using a kinetic helicase assay, we show that the eIF4G-RBD has a minimal effect on eIF4A helicase activity, demonstrating that the eIF4G-RBD is not required to coordinate eIF4F-dependent duplex unwinding. Unexpectedly, native gel electrophoresis and fluorescence polarization assays reveal a previously unidentified direct interaction between eIF4G and the 40S subunit. Using binding assays, our data show that this 40S subunit interaction is separate from the previously characterized interaction between eIF4G and eIF3. Thus, our work reveals how eIF4F can bind to the 40S subunit using eIF3-dependent and eIF3-independent binding domains to promote translation initiation.
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15
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Gao X, Jin Y, Zhu W, Wu X, Wang J, Guo C. Regulation of Eukaryotic Translation Initiation Factor 4E as a Potential Anticancer Strategy. J Med Chem 2023; 66:12678-12696. [PMID: 37725577 DOI: 10.1021/acs.jmedchem.3c00636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
Eukaryotic translation initiation factors (eIFs) are highly expressed in cancer cells, especially eIF4E, the central regulatory node driving cancer cell growth and a potential target for anticancer drugs. eIF4E-targeting strategies primarily focus on inhibiting eIF4E synthesis, interfering with eIF4E/eIF4G interactions, and targeting eIF4E phosphorylation and peptide inhibitors. Although some small-molecule inhibitors are in clinical trials, no eIF4E inhibitors are available for clinical use. We provide an overview of the regulatory mechanisms of eIF4E and summarize the progress in developing and discovering eIF4E inhibitor strategies. We propose that interference with eIF4E/eIF4G interactions will provide a new perspective for the design of eIF4E inhibitors and may be a preferred strategy.
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Affiliation(s)
- Xintao Gao
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Yonglong Jin
- The Affiliated Hospital of Qingdao University, Qingdao 266000, China
| | - Wenyong Zhu
- Department of Thoracic Surgery, Qilu Hospital (Qingdao), Cheeloo College of Medicine, Shandong University, Qingdao, 266035, China
| | - Xiaochen Wu
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Jing Wang
- Department of Biology Science and Technology, Baotou Teacher's College, Baotou 014030, China
| | - Chuanlong Guo
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
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16
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Bowazolo C, Morse D. Insights into daily metabolic changes of the dinoflagellate Lingulodinium from ribosome profiling. Cell Cycle 2023; 22:1343-1352. [PMID: 37125841 PMCID: PMC10228409 DOI: 10.1080/15384101.2023.2206771] [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: 01/20/2023] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 05/02/2023] Open
Abstract
The dinoflagellate Lingulodinium specializes its metabolism to perform different tasks better at specific times of day. For example, cells are specialized for photosynthesis during the day and bioluminescence and cell division at night. These rhythms are circadian as they are controlled by an endogenous circadian clock whose mechanism is currently unknown. Despite this, the metabolic rhythms follow coordinated changes in gene expression that occur at a translational level. These changes are revealed by ribosome profiling, a surrogate measure of protein synthesis rates in vivo. Lingulodinium regulates the synthesis rate of over three thousand transcripts. Peak synthesis rates for the different transcripts are clustered around three different times over a light/dark cycle. Furthermore, transcripts involved in the same metabolic process are coordinately regulated. We review the basic principles underlying the correlation of coordinated translation of cell metabolic pathway enzymes with known circadian rhythms, and offer examples where previously unsuspected rhythms are suggested by synchronized changes in gene expression.
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Affiliation(s)
- Carl Bowazolo
- Institut de Recherche en biologie Végétale, Département de Sciences Biologiques, Université de Montréal, Montréal, Québec, Canada
| | - David Morse
- Institut de Recherche en biologie Végétale, Département de Sciences Biologiques, Université de Montréal, Montréal, Québec, Canada
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17
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Seo J, Lee DE, Kim SM, Kim E, Kim JK. Licochalcone A Exerts Anti-Cancer Activity by Inhibiting STAT3 in SKOV3 Human Ovarian Cancer Cells. Biomedicines 2023; 11:biomedicines11051264. [PMID: 37238935 DOI: 10.3390/biomedicines11051264] [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: 02/23/2023] [Revised: 03/31/2023] [Accepted: 04/18/2023] [Indexed: 05/28/2023] Open
Abstract
Licochalcone A (LicA), a major active component of licorice, has been reported to exhibit various pharmacological actions. The purpose of this study was to investigate the anticancer activity of LicA and detail its molecular mechanisms against ovarian cancer. SKOV3 human ovarian cancer cells were used in this study. Cell viability was measured using a cell counting kit-8 assay. The percentages of apoptotic cells and cell cycle arrest were determined by flow cytometry and Muse flow cytometry. The expression levels of proteins regulating cell apoptosis, cell cycle, and the signal transducer and activator of transcription 3 (STAT3) signaling pathways were examined using Western blotting analysis. The results indicated that LicA treatment inhibited the cell viability of SKOV3 cells and induced G2/M phase arrest. Furthermore, LicA induced an increase in ROS levels, a reduction in mitochondrial membrane potential, and apoptosis accompanied by an increase in cleaved caspases and cytoplasmic cytochrome c. Additionally, LicA caused a dramatic decrease in STAT3 protein levels, but not mRNA levels, in SKOV3 cells. Treatment with LicA also reduced phosphorylation of the mammalian target of rapamycin and eukaryotic translation initiation factor 4E-binding protein in SKOV3 cells. The anti-cancer effects of LicA on SKOV3 cells might be mediated by reduced STAT3 translation and activation.
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Affiliation(s)
- Jeonghyeon Seo
- Department of Biomedical Science, Daegu Catholic University, Gyeongsan-si 38430, Republic of Korea
| | - Da Eun Lee
- Department of Biomedical Science, Daegu Catholic University, Gyeongsan-si 38430, Republic of Korea
| | - Seong Mi Kim
- Department of Biomedical Science, Daegu Catholic University, Gyeongsan-si 38430, Republic of Korea
| | - Eunjung Kim
- Department of Food Science and Nutrition, Daegu Catholic University, Gyeongsan-si 38430, Republic of Korea
| | - Jin-Kyung Kim
- Department of Biomedical Science, Daegu Catholic University, Gyeongsan-si 38430, Republic of Korea
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18
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Wu C, Xie T, Guo Y, Wang D, Qiu M, Han R, Qing G, Liang K, Liu H. CDK13 phosphorylates the translation machinery and promotes tumorigenic protein synthesis. Oncogene 2023; 42:1321-1330. [PMID: 36882522 DOI: 10.1038/s41388-023-02653-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 02/22/2023] [Accepted: 02/24/2023] [Indexed: 03/09/2023]
Abstract
Cyclin-dependent kinase 13 (CDK13) has been suggested to phosphorylate RNA polymerase II and is involved in transcriptional activation. However, whether CDK13 catalyzes other protein substrates and how CDK13 contributes to tumorigenesis remain largely unclear. We here identify key translation machinery components, 4E-BP1 and eIF4B, as novel CDK13 substrates. CDK13 directly phosphorylates 4E-BP1 at Thr46 and eIF4B at Ser422; genetically or pharmacologically inhibiting CDK13 disrupts mRNA translation. Polysome profiling analysis shows that MYC oncoprotein synthesis strictly depends on CDK13-regulated translation in colorectal cancer (CRC), and CDK13 is required for CRC cell proliferation. As mTORC1 is implicated in 4E-BP1 and eIF4B phosphorylation, inactivation of CDK13 in combination with the mTORC1 inhibitor rapamycin further dephosphorylates 4E-BP1 and eIF4B and blocks protein synthesis. As a result, dual inhibition of CDK13 and mTORC1 induces more profound tumor cell death. These findings clarify the pro-tumorigenic role of CDK13 by direct phosphorylation of translation initiation factors and enhancing protein synthesis. Therefore, therapeutic targeting of CDK13 alone or in combination with rapamycin may pave a new way for cancer treatment.
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Affiliation(s)
- Chao Wu
- Department of Hematology, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, 430071, Wuhan, China.,Frontier Science Center of Immunology and Metabolism, Wuhan University, 430071, Wuhan, China
| | - Ting Xie
- Department of Hematology, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, 430071, Wuhan, China.,Frontier Science Center of Immunology and Metabolism, Wuhan University, 430071, Wuhan, China
| | - Ying Guo
- Frontier Science Center of Immunology and Metabolism, Wuhan University, 430071, Wuhan, China
| | - Donghai Wang
- Frontier Science Center of Immunology and Metabolism, Wuhan University, 430071, Wuhan, China
| | - Min Qiu
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, 430071, Wuhan, China
| | - Ruyi Han
- Frontier Science Center of Immunology and Metabolism, Wuhan University, 430071, Wuhan, China
| | - Guoliang Qing
- Frontier Science Center of Immunology and Metabolism, Wuhan University, 430071, Wuhan, China
| | - Kaiwei Liang
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, 430071, Wuhan, China
| | - Hudan Liu
- Department of Hematology, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, 430071, Wuhan, China. .,Frontier Science Center of Immunology and Metabolism, Wuhan University, 430071, Wuhan, China.
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19
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Paul MS, Duncan AR, Genetti CA, Pan H, Jackson A, Grant PE, Shi J, Pinelli M, Brunetti-Pierri N, Garza-Flores A, Shahani D, Saneto RP, Zampino G, Leoni C, Agolini E, Novelli A, Blümlein U, Haack TB, Heinritz W, Matzker E, Alhaddad B, Abou Jamra R, Bartolomaeus T, AlHamdan S, Carapito R, Isidor B, Bahram S, Ritter A, Izumi K, Shakked BP, Barel O, Ben Zeev B, Begtrup A, Carere DA, Mullegama SV, Palculict TB, Calame DG, Schwan K, Aycinena ARP, Traberg R, Douzgou S, Pirt H, Ismayilova N, Banka S, Chao HT, Agrawal PB. Rare EIF4A2 variants are associated with a neurodevelopmental disorder characterized by intellectual disability, hypotonia, and epilepsy. Am J Hum Genet 2023; 110:120-145. [PMID: 36528028 PMCID: PMC9892767 DOI: 10.1016/j.ajhg.2022.11.011] [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: 04/15/2022] [Accepted: 11/15/2022] [Indexed: 12/23/2022] Open
Abstract
Eukaryotic initiation factor-4A2 (EIF4A2) is an ATP-dependent RNA helicase and a member of the DEAD-box protein family that recognizes the 5' cap structure of mRNAs, allows mRNA to bind to the ribosome, and plays an important role in microRNA-regulated gene repression. Here, we report on 15 individuals from 14 families presenting with global developmental delay, intellectual disability, hypotonia, epilepsy, and structural brain anomalies, all of whom have extremely rare de novo mono-allelic or inherited bi-allelic variants in EIF4A2. Neurodegeneration was predominantly reported in individuals with bi-allelic variants. Molecular modeling predicts these variants would perturb structural interactions in key protein domains. To determine the pathogenicity of the EIF4A2 variants in vivo, we examined the mono-allelic variants in Drosophila melanogaster (fruit fly) and identified variant-specific behavioral and developmental defects. The fruit fly homolog of EIF4A2 is eIF4A, a negative regulator of decapentaplegic (dpp) signaling that regulates embryo patterning, eye and wing morphogenesis, and stem cell identity determination. Our loss-of-function (LOF) rescue assay demonstrated a pupal lethality phenotype induced by loss of eIF4A, which was fully rescued with human EIF4A2 wild-type (WT) cDNA expression. In comparison, the EIF4A2 variant cDNAs failed or incompletely rescued the lethality. Overall, our findings reveal that EIF4A2 variants cause a genetic neurodevelopmental syndrome with both LOF and gain of function as underlying mechanisms.
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Affiliation(s)
- Maimuna S Paul
- Department of Pediatrics, Division of Neurology and Developmental Neuroscience, Baylor College of Medicine, Houston, TX, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Anna R Duncan
- Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA; Division of Neonatology and Newborn Medicine, Massachusetts General Hospital for Children, Boston, MA, USA
| | - Casie A Genetti
- Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA; Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Hongling Pan
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Adam Jackson
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9WL, UK; Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Health Innovation Manchester, Manchester, UK
| | - Patricia E Grant
- Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA; Department of Radiology, Boston Children's Hospital, Boston, MA, USA
| | - Jiahai Shi
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Michele Pinelli
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy; Department of Translational Medicine, University of Naples "Federico II", Naples, Italy
| | - Nicola Brunetti-Pierri
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy; Department of Translational Medicine, University of Naples "Federico II", Naples, Italy
| | | | - Dave Shahani
- Department of Neurology and Epileptology, Cook Children's Hospital, Fort Worth, TX 76104, USA
| | - Russell P Saneto
- Neuroscience Institute, Center for Integrative Brain Research, Departments of Pediatric Neurology and Neurology Seattle Children's Hospital, University of Washington, Seattle, WA, USA
| | - Giuseppe Zampino
- Center for Rare Diseases and Birth Defects, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli, Rome, Italy; Catholic University of the Sacred Heart, Faculty of Medicine and Surgery, Rome, Italy
| | - Chiara Leoni
- Center for Rare Diseases and Birth Defects, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli, Rome, Italy
| | - Emanuele Agolini
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Antonio Novelli
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Ulrike Blümlein
- Department of Pediatrics, Carl-Thiem-Klinikum Cottbus, Cottbus, Germany
| | - Tobias B Haack
- Institute of Human Genetics, Technical University of Munich, 81675 Munich, Germany; Institute of Medical Genetics and Applied Genomics, University of Tuebingen, 72076 Tuebingen, Germany
| | | | - Eva Matzker
- Department of Pediatrics, Carl-Thiem-Klinikum Cottbus, Cottbus, Germany
| | - Bader Alhaddad
- Institute of Human Genetics, Technical University of Munich, 81675 Munich, Germany
| | - Rami Abou Jamra
- Institute of Human Genetics, University of Leipzig Medical Center, 04103 Leipzig, Germany
| | - Tobias Bartolomaeus
- Institute of Human Genetics, University of Leipzig Medical Center, 04103 Leipzig, Germany
| | | | - Raphael Carapito
- Laboratoire 'ImmunoRhumatologie Moléculaire, Plateforme GENOMAX, INSERM UMR_S 1109, Faculté de Médecine, Fédération Hospitalo-Universitaire OMICARE, Fédération de Médecine Translationnelle de Strasbourg (FMTS), ITI TRANSPLANTEX NG, Université de Strasbourg, 67085 Strasbourg, France; Service d'Immunologie Biologique, Plateau Technique de Biologie, Pôle de Biologie, Nouvel Hôpital Civil, Hôpitaux Universitaires de Strasbourg, 1 Place de l'Hôpital, 67091, Strasbourg, France
| | - Bertrand Isidor
- Service de Génétique Médicale, Hôpital Hôtel-Dieu, Centre Hospitalier Universitaire de Nantes, Nantes, France
| | - Seiamak Bahram
- Laboratoire 'ImmunoRhumatologie Moléculaire, Plateforme GENOMAX, INSERM UMR_S 1109, Faculté de Médecine, Fédération Hospitalo-Universitaire OMICARE, Fédération de Médecine Translationnelle de Strasbourg (FMTS), ITI TRANSPLANTEX NG, Université de Strasbourg, 67085 Strasbourg, France; Service d'Immunologie Biologique, Plateau Technique de Biologie, Pôle de Biologie, Nouvel Hôpital Civil, Hôpitaux Universitaires de Strasbourg, 1 Place de l'Hôpital, 67091, Strasbourg, France
| | - Alyssa Ritter
- Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Kosuke Izumi
- Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Ben Pode Shakked
- Pediatric Neurology Department, The Edmond and Lilly Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Israel; Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Ortal Barel
- Pediatric Neurology Department, The Edmond and Lilly Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Israel
| | - Bruria Ben Zeev
- Pediatric Neurology Department, The Edmond and Lilly Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Israel; Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Amber Begtrup
- Clinical Genomics Program, GeneDx, Gaithersburg, MD 20877, USA
| | | | | | | | - Daniel G Calame
- Section of Pediatric Neurology and Developmental Neurosciences, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | | | | | - Rasa Traberg
- Department of Genetics and Molecular Medicine, Hospital of Lithuanian University of Health Sciences Kauno klinikos, Kaunas, Lithuania
| | - Sofia Douzgou
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9WL, UK; Department of Medical Genetics, Haukeland University Hospital, Bergen, Norway
| | - Harrison Pirt
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9WL, UK
| | - Naila Ismayilova
- Department of Paediatric Neurology, Chelsea and Westminster NHS Foundation Trust, London, UK
| | - Siddharth Banka
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9WL, UK; Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Health Innovation Manchester, Manchester, UK
| | - Hsiao-Tuan Chao
- Department of Pediatrics, Division of Neurology and Developmental Neuroscience, Baylor College of Medicine, Houston, TX, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA; McNair Medical Institute, The Robert and Janice McNair Foundation, Houston, TX, USA.
| | - Pankaj B Agrawal
- Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA; Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA.
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20
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Gale JR, Gedeon JY, Donnelly CJ, Gold MS. Local translation in primary afferents and its contribution to pain. Pain 2022; 163:2302-2314. [PMID: 35438669 PMCID: PMC9579217 DOI: 10.1097/j.pain.0000000000002658] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 04/08/2022] [Indexed: 02/06/2023]
Abstract
ABSTRACT Chronic pain remains a significant problem due to its prevalence, impact, and limited therapeutic options. Progress in addressing chronic pain is dependent on a better understanding of underlying mechanisms. Although the available evidence suggests that changes within the central nervous system contribute to the initiation and maintenance of chronic pain, it also suggests that the primary afferent plays a critical role in all phases of the manifestation of chronic pain in most of those who suffer. Most notable among the changes in primary afferents is an increase in excitability or sensitization. A number of mechanisms have been identified that contribute to primary afferent sensitization with evidence for both increases in pronociceptive signaling molecules, such as voltage-gated sodium channels, and decreases in antinociceptive signaling molecules, such as voltage-dependent or calcium-dependent potassium channels. Furthermore, these changes in signaling molecules seem to reflect changes in gene expression as well as posttranslational processing. A mechanism of sensitization that has received far less attention, however, is the local or axonal translation of these signaling molecules. A growing body of evidence indicates that this process not only is dynamically regulated but also contributes to the initiation and maintenance of chronic pain. Here, we review the biology of local translation in primary afferents and its relevance to pain pathobiology.
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Affiliation(s)
- Jenna R Gale
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - Jeremy Y Gedeon
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | | | - Michael S Gold
- Corresponding author: Michael S Gold, PhD, Department of Neurobiology, University of Pittsburgh School of Medicine, 200 Lothrop Street, Pittsburgh, PA 15213, P: 412-383-5367,
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21
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Wang J, Shin BS, Alvarado C, Kim JR, Bohlen J, Dever TE, Puglisi JD. Rapid 40S scanning and its regulation by mRNA structure during eukaryotic translation initiation. Cell 2022; 185:4474-4487.e17. [PMID: 36334590 PMCID: PMC9691599 DOI: 10.1016/j.cell.2022.10.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 08/22/2022] [Accepted: 10/05/2022] [Indexed: 11/06/2022]
Abstract
How the eukaryotic 43S preinitiation complex scans along the 5' untranslated region (5' UTR) of a capped mRNA to locate the correct start codon remains elusive. Here, we directly track yeast 43S-mRNA binding, scanning, and 60S subunit joining by real-time single-molecule fluorescence spectroscopy. 43S engagement with mRNA occurs through a slow, ATP-dependent process driven by multiple initiation factors including the helicase eIF4A. Once engaged, 43S scanning occurs rapidly and directionally at ∼100 nucleotides per second, independent of multiple cycles of ATP hydrolysis by RNA helicases post ribosomal loading. Scanning ribosomes can proceed through RNA secondary structures, but 5' UTR hairpin sequences near start codons drive scanning ribosomes at start codons backward in the 5' direction, requiring rescanning to arrive once more at a start codon. Direct observation of scanning ribosomes provides a mechanistic framework for translational regulation by 5' UTR structures and upstream near-cognate start codons.
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Affiliation(s)
- Jinfan Wang
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Byung-Sik Shin
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Carlos Alvarado
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Joo-Ran Kim
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Jonathan Bohlen
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, Institut National de la Santé et de la Recherche Médicale U1163, Paris, France; University of Paris, Imagine Institute, Paris, France
| | - Thomas E Dever
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.
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22
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Preinitiation Complex Loading onto mRNAs with Long versus Short 5' TLs. Int J Mol Sci 2022; 23:ijms232113369. [PMID: 36362157 PMCID: PMC9658832 DOI: 10.3390/ijms232113369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022] Open
Abstract
The first step in translation initiation consists in the recruitment of the small ribosome onto the mRNA. This preinitiation complex (PIC) loads via interactions with eIF4F that has assembled on the 5' cap. It then scans the 5' TL (transcript leader) to locate a start site. The molecular architecture of the PIC-mRNA complex over the cap is beginning to be resolved. As part of this, we have been examining the role of the 5' TL length. We observed in vivo initiation events on AUG codons positioned within 3 nts of the 5' cap and robust initiation in vitro at start sites immediately downstream of the 5' end. Ribosomal toe-printing confirmed the positioning of these codons within the P site, indicating that the ribosome reads from the +1 position. To explore differences in the eIF4E-5' cap interaction in the context of long versus short TL, we followed the fate of the eIF4E-cap interaction using a novel solid phase in vitro expression assay. We observed that ribosome recruitment onto a short TL disrupts the eIF4E-cap contact releasing all the mRNA from the solid phase, whereas with a long the mRNA distributes between both phases. These results are discussed in the context of current recruitment models.
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23
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Cai Y, Liu K, Wu P, Yuan R, He F, Zou J. Association of mTORC1‑dependent circulating protein levels with cataract formation: a mendelian randomization study. BMC Genomics 2022; 23:719. [PMID: 36271348 PMCID: PMC9587558 DOI: 10.1186/s12864-022-08925-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 09/28/2022] [Indexed: 11/10/2022] Open
Abstract
Background The mechanistic target of rapamycin (mTOR) signal pathway plays a critical regulating role in the occurrence and development of cataract. However, the role of mTORC1 downstream proteins, including ribosomal protein S6K (RP-S6K), eukaryotic initiation factor 4E-binding protein (EIF4EBP), eukaryotic initiation factor 4G (EIF-4G), eukaryotic initiation factor 4E (EIF-4E), and eukaryotic initiation factor 4A (EIF-4A), in regulating cataract development is still unknown. Herein, we conducted a mendelian randomization (MR) study to understand the function of mTORC1 signaling in the process of cataract development. Results The causal estimate was evaluated with inverse-variance weighted (IVW) estimate, weighted median estimator, MR-Egger and MR robust adjusted profile score (MR. RAPS). The single-nucleotide polymorphisms (SNPs), P<5 × 10− 6 and r2<0.05, were selected to genetically predict the RP-S6K, EIF4EBP, EIF-4E, EIF-4A, and EIF-4G. We included a total of 26,758 cases and 189,604 controls in this MR study. The study revealed causal association between circulating EIF4EBP (OR 1.09, 95% confidence interval 1.03,1.16, P = 0.004), RP-S6K (OR 1.04, 95% confidence interval 1.01, 1.08, P = 0.02) and cataract formation with IVW estimate. Whereas after correcting outliers, MR robust adjusted profile score (MR. RAPS) shows consistent result with IVW for EIF4EBP (OR = 1.08, 95%CI:1.05–1.11, P = 0.007). The observation strengthened the confidence in the true causal associations. However, no association was found for circulating EIF-4E (OR 1.03, 95% confidence interval 0.97, 1.09, P = 0.31), EIF-4A (OR 1.02, 95% confidence interval 0.98, 1.07, P = 0.34), and EIF-4G (OR 1.02, 95% confidence interval 0.94, 1.01, P = 0.64) levels with cataract formation. No evidence of heterogeneity and unbalanced horizontal pleiotropy was detected. Conclusion The MR study suggests that EIF4EBP is a high-risk factor for cataract development. There may be a potential causal association between the mTORC1/EIF4EBP axis and cataract. This research highlights the potential mechanism for cataract development and a genetic target to prevent as well as treat cataracts. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08925-7.
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Affiliation(s)
- Yingjun Cai
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Central South University, 410008, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, 410008, Changsha, Hunan, China
| | - Kangcheng Liu
- Jiangxi Clinical Research center for Ophthalmic Disease, Jiangxi Research Institute of Ophthalmology and Visual Science, Affiliated Eye Hospital of Nanchang University, Nanchang, China
| | - Pengfei Wu
- Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Ruolan Yuan
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Central South University, 410008, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, 410008, Changsha, Hunan, China
| | - Fei He
- The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Jing Zou
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Central South University, 410008, Changsha, Hunan, China. .,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, 410008, Changsha, Hunan, China.
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24
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Bezerra MJR, Moura DMN, Freire ER, Holetz FB, Reis CRS, Monteiro TTS, Pinto ARS, Zhang N, Rezende AM, Pereira-Neves A, Figueiredo RCBQ, Clayton C, Field MC, Carrington M, de Melo Neto OP. Distinct mRNA and protein interactomes highlight functional differentiation of major eIF4F-like complexes from Trypanosoma brucei. Front Mol Biosci 2022; 9:971811. [PMID: 36275617 PMCID: PMC9585242 DOI: 10.3389/fmolb.2022.971811] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Gene expression in pathogenic protozoans of the family Trypanosomatidae has several novel features, including multiple eIF4F-like complexes involved in protein synthesis. The eukaryotic eIF4F complex, formed mainly by eIF4E and eIF4G subunits, is responsible for the canonical selection of mRNAs required for the initiation of mRNA translation. The best-known complexes implicated in translation in trypanosomatids are based on two related pairs of eIF4E and eIF4G subunits (EIF4E3/EIF4G4 and EIF4E4/EIF4G3), whose functional distinctions remain to be fully described. Here, to define interactomes associated with both complexes in Trypanosoma brucei procyclic forms, we performed parallel immunoprecipitation experiments followed by identification of proteins co-precipitated with the four tagged eIF4E and eIF4G subunits. A number of different protein partners, including RNA binding proteins and helicases, specifically co-precipitate with each complex. Highlights with the EIF4E4/EIF4G3 pair include RBP23, PABP1, EIF4AI and the CRK1 kinase. Co-precipitated partners with the EIF4E3/EIF4G4 pair are more diverse and include DRBD2, PABP2 and different zinc-finger proteins and RNA helicases. EIF4E3/EIF4G4 are essential for viability and to better define their role, we further investigated their phenotypes after knockdown. Depletion of either EIF4E3/EIF4G4 mRNAs lead to aberrant morphology with a more direct impact on events associated with cytokinesis. We also sought to identify those mRNAs differentially associated with each complex through CLIP-seq with the two eIF4E subunits. Predominant among EIF4E4-bound transcripts are those encoding ribosomal proteins, absent from those found with EIF4E3, which are generally more diverse. RNAi mediated depletion of EIF4E4, which does not affect proliferation, does not lead to changes in mRNAs or proteins associated with EIF4E3, confirming a lack of redundancy and distinct roles for the two complexes.
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Affiliation(s)
- Maria J. R. Bezerra
- Aggeu Magalhães Institute, Oswaldo Cruz Foundation, Recife, Pernambuco, Brazil
- Department of Genetics, Federal University of Pernambuco, Recife, Pernambuco, Brazil
| | | | - Eden R. Freire
- Carlos Chagas Institute, Oswaldo Cruz Foundation, Curitiba, Pernambuco, Brazil
| | - Fabiola B. Holetz
- Carlos Chagas Institute, Oswaldo Cruz Foundation, Curitiba, Pernambuco, Brazil
| | | | | | - Adriana R. S. Pinto
- Aggeu Magalhães Institute, Oswaldo Cruz Foundation, Recife, Pernambuco, Brazil
| | - Ning Zhang
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Antonio M. Rezende
- Aggeu Magalhães Institute, Oswaldo Cruz Foundation, Recife, Pernambuco, Brazil
| | | | | | - Christine Clayton
- Heidelberg University Center for Molecular Biology, Heidelberg, Germany
| | - Mark C. Field
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czechia
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Osvaldo P. de Melo Neto
- Aggeu Magalhães Institute, Oswaldo Cruz Foundation, Recife, Pernambuco, Brazil
- *Correspondence: Osvaldo P. de Melo Neto,
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25
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Pechar GS, Donaire L, Gosalvez B, García‐Almodovar C, Sánchez‐Pina MA, Truniger V, Aranda MA. Editing melon eIF4E associates with virus resistance and male sterility. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:2006-2022. [PMID: 35778883 PMCID: PMC9491454 DOI: 10.1111/pbi.13885] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 06/19/2022] [Accepted: 06/23/2022] [Indexed: 05/20/2023]
Abstract
The cap-binding protein eIF4E, through its interaction with eIF4G, constitutes the core of the eIF4F complex, which plays a key role in the circularization of mRNAs and their subsequent cap-dependent translation. In addition to its fundamental role in mRNA translation initiation, other functions have been described or suggested for eIF4E, including acting as a proviral factor and participating in sexual development. We used CRISPR/Cas9 genome editing to generate melon eif4e knockout mutant lines. Editing worked efficiently in melon, as we obtained transformed plants with a single-nucleotide deletion in homozygosis in the first eIF4E exon already in a T0 generation. Edited and non-transgenic plants of a segregating F2 generation were inoculated with Moroccan watermelon mosaic virus (MWMV); homozygous mutant plants showed virus resistance, while heterozygous and non-mutant plants were infected, in agreement with our previous results with plants silenced in eIF4E. Interestingly, all homozygous edited plants of the T0 and F2 generations showed a male sterility phenotype, while crossing with wild-type plants restored fertility, displaying a perfect correlation between the segregation of the male sterility phenotype and the segregation of the eif4e mutation. Morphological comparative analysis of melon male flowers along consecutive developmental stages showed postmeiotic abnormal development for both microsporocytes and tapetum, with clear differences in the timing of tapetum degradation in the mutant versus wild-type. An RNA-Seq analysis identified critical genes in pollen development that were down-regulated in flowers of eif4e/eif4e plants, and suggested that eIF4E-specific mRNA translation initiation is a limiting factor for male gametes formation in melon.
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Affiliation(s)
- Giuliano S. Pechar
- Department of Stress Biology and Plant PathologyCentro de Edafología y Biología Aplicada del Segura (CEBAS)‐CSICMurciaSpain
| | - Livia Donaire
- Department of Stress Biology and Plant PathologyCentro de Edafología y Biología Aplicada del Segura (CEBAS)‐CSICMurciaSpain
| | - Blanca Gosalvez
- Department of Stress Biology and Plant PathologyCentro de Edafología y Biología Aplicada del Segura (CEBAS)‐CSICMurciaSpain
| | - Carlos García‐Almodovar
- Department of Stress Biology and Plant PathologyCentro de Edafología y Biología Aplicada del Segura (CEBAS)‐CSICMurciaSpain
| | - María Amelia Sánchez‐Pina
- Department of Stress Biology and Plant PathologyCentro de Edafología y Biología Aplicada del Segura (CEBAS)‐CSICMurciaSpain
| | - Verónica Truniger
- Department of Stress Biology and Plant PathologyCentro de Edafología y Biología Aplicada del Segura (CEBAS)‐CSICMurciaSpain
| | - Miguel A. Aranda
- Department of Stress Biology and Plant PathologyCentro de Edafología y Biología Aplicada del Segura (CEBAS)‐CSICMurciaSpain
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26
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Kang JY, Wen Z, Pan D, Zhang Y, Li Q, Zhong A, Yu X, Wu YC, Chen Y, Zhang X, Kou PC, Geng J, Wang YY, Hua MM, Zong R, Li B, Shi HJ, Li D, Fu XD, Li J, Nelson DL, Guo X, Zhou Y, Gou LT, Huang Y, Liu MF. LLPS of FXR1 drives spermiogenesis by activating translation of stored mRNAs. Science 2022; 377:eabj6647. [PMID: 35951695 DOI: 10.1126/science.abj6647] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Postmeiotic spermatids use a unique strategy to coordinate gene expression with morphological transformation, in which transcription and translation take place at separate developmental stages, but how mRNAs stored as translationally inert messenger ribonucleoproteins in developing spermatids become activated remains largely unknown. Here, we report that the RNA binding protein FXR1, a member of the fragile X-related (FXR) family, is highly expressed in late spermatids and undergoes liquid-liquid phase separation (LLPS) to merge messenger ribonucleoprotein granules with the translation machinery to convert stored mRNAs into a translationally activated state. Germline-specific Fxr1 ablation in mice impaired the translation of target mRNAs and caused defective spermatid development and male infertility, and a phase separation-deficient FXR1L351P mutation in Fxr1 knock-in mice produced the same developmental defect. These findings uncover a mechanism for translational reprogramming with LLPS as a key driver in spermiogenesis.
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Affiliation(s)
- Jun-Yan Kang
- State Key Laboratory of Molecular Biology, State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Ze Wen
- State Key Laboratory of Molecular Biology, State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Duo Pan
- State Key Laboratory of Molecular Biology, State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Yuhan Zhang
- Shanghai Key Laboratory of Biliary Tract Disease Research, Shanghai Research Center of Biliary Tract Disease, Department of General Surgery, Xinhua Hospital, affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qing Li
- State Key Laboratory of Molecular Biology, State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Ai Zhong
- State Key Laboratory of Molecular Biology, State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Xinghai Yu
- State Key Laboratory of Virology, Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China.,Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China
| | - Yi-Chen Wu
- State Key Laboratory of Molecular Biology, State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Yu Chen
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xiangzheng Zhang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Peng-Cheng Kou
- State Key Laboratory of Molecular Biology, State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Junlan Geng
- State Key Laboratory of Molecular Biology, State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Ying-Yi Wang
- State Key Laboratory of Molecular Biology, State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Min-Min Hua
- State Key Laboratory of Molecular Biology, State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China.,NHC Key Lab of Reproduction Regulation (Shanghai Institute of Planned Parenthood Research), Pharmacy School, Fudan University, Shanghai, China
| | - Ruiting Zong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Biao Li
- Department of Nuclear Medicine, Rui Jin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Hui-Juan Shi
- NHC Key Lab of Reproduction Regulation (Shanghai Institute of Planned Parenthood Research), Pharmacy School, Fudan University, Shanghai, China
| | - Dangsheng Li
- State Key Laboratory of Molecular Biology, State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Xiang-Dong Fu
- Department of Cellular and Molecular Medicine, University of California, San Diego, CA, USA
| | - Jinsong Li
- State Key Laboratory of Molecular Biology, State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China.,Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China.,School of Life Science and Technology, Shanghai Tech University, Shanghai, China
| | - David L Nelson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Xuejiang Guo
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yu Zhou
- State Key Laboratory of Virology, Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China.,Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China
| | - Lan-Tao Gou
- State Key Laboratory of Molecular Biology, State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Ying Huang
- Shanghai Key Laboratory of Biliary Tract Disease Research, Shanghai Research Center of Biliary Tract Disease, Department of General Surgery, Xinhua Hospital, affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Mo-Fang Liu
- State Key Laboratory of Molecular Biology, State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China.,Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China.,School of Life Science and Technology, Shanghai Tech University, Shanghai, China
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27
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Izidoro MS, Sokabe M, Villa N, Merrick WC, Fraser CS. Human eukaryotic initiation factor 4E (eIF4E) and the nucleotide-bound state of eIF4A regulate eIF4F binding to RNA. J Biol Chem 2022; 298:102368. [PMID: 35963437 PMCID: PMC9483636 DOI: 10.1016/j.jbc.2022.102368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/05/2022] [Accepted: 08/09/2022] [Indexed: 11/30/2022] Open
Abstract
During translation initiation, the underlying mechanism by which the eukaryotic initiation factor (eIF) 4E, eIF4A, and eIF4G components of eIF4F coordinate their binding activities to regulate eIF4F binding to mRNA is poorly defined. Here, we used fluorescence anisotropy to generate thermodynamic and kinetic frameworks for the interaction of uncapped RNA with human eIF4F. We demonstrate that eIF4E binding to an autoinhibitory domain in eIF4G generates a high-affinity binding conformation of the eIF4F complex for RNA. In addition, we show that the nucleotide-bound state of the eIF4A component further regulates uncapped RNA binding by eIF4F, with a four-fold decrease in the equilibrium dissociation constant observed in the presence versus the absence of ATP. Monitoring uncapped RNA dissociation in real time reveals that ATP reduces the dissociation rate constant of RNA for eIF4F by ∼4-orders of magnitude. Thus, release of ATP from eIF4A places eIF4F in a dynamic state that has very fast association and dissociation rates from RNA. Monitoring the kinetic framework for eIF4A binding to eIF4G revealed two different rate constants that likely reflect two conformational states of the eIF4F complex. Furthermore, we determined that the eIF4G autoinhibitory domain promotes a more stable, less dynamic, eIF4A-binding state, which is overcome by eIF4E binding. Overall, our data support a model whereby eIF4E binding to eIF4G/4A stabilizes a high-affinity RNA-binding state of eIF4F and enables eIF4A to adopt a more dynamic interaction with eIF4G. This dynamic conformation may contribute to the ability of eIF4F to rapidly bind and release mRNA during scanning.
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Affiliation(s)
- Mario Servulo Izidoro
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA 95616
| | - Masaaki Sokabe
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA 95616
| | - Nancy Villa
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA 95616
| | - William C Merrick
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA 95616
| | - Christopher S Fraser
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA 95616.
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28
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Çetin B, O’Leary SE. mRNA- and factor-driven dynamic variability controls eIF4F-cap recognition for translation initiation. Nucleic Acids Res 2022; 50:8240-8261. [PMID: 35871304 PMCID: PMC9371892 DOI: 10.1093/nar/gkac631] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/29/2022] [Accepted: 07/20/2022] [Indexed: 11/29/2022] Open
Abstract
mRNA 5′ cap recognition by eIF4F is a key element of eukaryotic translational control. Kinetic differences in eIF4F–mRNA interactions have long been proposed to mediate translation-efficiency differences between mRNAs, and recent transcriptome-wide studies have revealed significant heterogeneity in eIF4F engagement with differentially-translated mRNAs. However, detailed kinetic information exists only for eIF4F interactions with short model RNAs. We developed and applied single-molecule fluorescence approaches to directly observe real-time Saccharomyces cerevisiae eIF4F subunit interactions with full-length polyadenylated mRNAs. We found that eIF4E–mRNA association rates linearly anticorrelate with mRNA length. eIF4G–mRNA interaction accelerates eIF4E–mRNA association in proportion to mRNA length, as does an eIF4F-independent activity of eIF4A, though cap-proximal secondary structure still plays an important role in defining the final association rates. eIF4F–mRNA interactions remained dominated by effects of eIF4G, but were modulated to different extents for different mRNAs by the presence of eIF4A and ATP. We also found that eIF4A-catalyzed ATP hydrolysis ejects eIF4E, and likely eIF4E•eIF4G from the mRNA after initial eIF4F•mRNA complex formation, suggesting a mechanism to prepare the mRNA 5′ end for ribosome recruitment. Our results support a role for mRNA-specific, factor-driven eIF4F association rates in kinetically controlling translation.
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Affiliation(s)
- Burak Çetin
- Graduate Program in Cell, Molecular, and Developmental Biology, University of California Riverside , Riverside, CA 92521, USA
| | - Seán E O’Leary
- Graduate Program in Cell, Molecular, and Developmental Biology, University of California Riverside , Riverside, CA 92521, USA
- Department of Biochemistry, University of California Riverside , Riverside, CA 92521, USA
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Fenton DA, Kiniry SJ, Yordanova MM, Baranov PV, Morrissey JP. Development of a ribosome profiling protocol to study translation in Kluyveromyces marxianus. FEMS Yeast Res 2022; 22:foac024. [PMID: 35521744 PMCID: PMC9246280 DOI: 10.1093/femsyr/foac024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 04/17/2022] [Accepted: 05/04/2022] [Indexed: 11/27/2022] Open
Abstract
Kluyveromyces marxianus is an interesting and important yeast because of particular traits such as thermotolerance and rapid growth, and for applications in food and industrial biotechnology. For both understanding its biology and developing bioprocesses, it is important to understand how K. marxianus responds and adapts to changing environments. For this, a full suite of omics tools to measure and compare global patterns of gene expression and protein synthesis is needed. We report here the development of a ribosome profiling method for K. marxianus, which allows codon resolution of translation on a genome-wide scale by deep sequencing of ribosome locations on mRNAs. To aid in the analysis and sharing of ribosome profiling data, we added the K. marxianus genome as well as transcriptome and ribosome profiling data to the publicly accessible GWIPS-viz and Trips-Viz browsers. Users are able to upload custom ribosome profiling and RNA-Seq data to both browsers, therefore allowing easy analysis and sharing of data. We also provide a set of step-by-step protocols for the experimental and bioinformatic methods that we developed.
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Affiliation(s)
- Darren A Fenton
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
- School of Microbiology, Environmental Research Institute, APC Microbiome Institute, SUSFERM Fermentation Science Centre, University College Cork, Cork T12 K8AF, Ireland
| | - Stephen J Kiniry
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - Martina M Yordanova
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - John P Morrissey
- School of Microbiology, Environmental Research Institute, APC Microbiome Institute, SUSFERM Fermentation Science Centre, University College Cork, Cork T12 K8AF, Ireland
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Single-Cell RNA-Seq Analysis of Cells from Degenerating and Non-Degenerating Intervertebral Discs from the Same Individual Reveals New Biomarkers for Intervertebral Disc Degeneration. Int J Mol Sci 2022; 23:ijms23073993. [PMID: 35409356 PMCID: PMC8999935 DOI: 10.3390/ijms23073993] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 03/31/2022] [Accepted: 04/01/2022] [Indexed: 02/07/2023] Open
Abstract
In this study, we used single-cell transcriptomic analysis to identify new specific biomarkers for nucleus pulposus (NP) and inner annulus fibrosis (iAF) cells, and to define cell populations within non-degenerating (nD) and degenerating (D) human intervertebral discs (IVD) of the same individual. Cluster analysis based on differential gene expression delineated 14 cell clusters. Gene expression profiles at single-cell resolution revealed the potential functional differences linked to degeneration, and among NP and iAF subpopulations. GO and KEGG analyses discovered molecular functions, biological processes, and transcription factors linked to cell type and degeneration state. We propose two lists of biomarkers, one as specific cell type, including C2orf40, MGP, MSMP, CD44, EIF1, LGALS1, RGCC, EPYC, HILPDA, ACAN, MT1F, CHI3L1, ID1, ID3 and TMED2. The second list proposes predictive IVD degeneration genes, including MT1G, SPP1, HMGA1, FN1, FBXO2, SPARC, VIM, CTGF, MGST1, TAF1D, CAPS, SPTSSB, S100A1, CHI3L2, PLA2G2A, TNRSF11B, FGFBP2, MGP, SLPI, DCN, MT-ND2, MTCYB, ADIRF, FRZB, CLEC3A, UPP1, S100A2, PRG4, COL2A1, SOD2 and MT2A. Protein and mRNA expression of MGST1, vimentin, SOD2 and SYF2 (p29) genes validated our scRNA-seq findings. Our data provide new insights into disc cells phenotypes and biomarkers of IVD degeneration that could improve diagnostic and therapeutic options.
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Structural and molecular basis for Cardiovirus 2A protein as a viral gene expression switch. Nat Commun 2021; 12:7166. [PMID: 34887415 PMCID: PMC8660796 DOI: 10.1038/s41467-021-27400-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 11/12/2021] [Indexed: 12/21/2022] Open
Abstract
Programmed –1 ribosomal frameshifting (PRF) in cardioviruses is activated by the 2A protein, a multi-functional virulence factor that also inhibits cap-dependent translational initiation. Here we present the X-ray crystal structure of 2A and show that it selectively binds to a pseudoknot-like conformation of the PRF stimulatory RNA element in the viral genome. Using optical tweezers, we demonstrate that 2A stabilises this RNA element, likely explaining the increase in PRF efficiency in the presence of 2A. Next, we demonstrate a strong interaction between 2A and the small ribosomal subunit and present a cryo-EM structure of 2A bound to initiated 70S ribosomes. Multiple copies of 2A bind to the 16S rRNA where they may compete for binding with initiation and elongation factors. Together, these results define the structural basis for RNA recognition by 2A, show how 2A-mediated stabilisation of an RNA pseudoknot promotes PRF, and reveal how 2A accumulation may shut down translation during virus infection. Many RNA viruses employ programmed –1 ribosomal frameshifting (PRF) to expand their coding capacity and optimize production of viral proteins. Here, the authors report structural and biophysical analysis of protein 2A from a cardiovirus, with insights into the mechanism of its PRF-stimulatory function.
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Identification of mRNA 5' cap-associated proteins in the human malaria parasite Plasmodium falciparum. Mol Biochem Parasitol 2021; 247:111443. [PMID: 34890716 DOI: 10.1016/j.molbiopara.2021.111443] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/11/2021] [Accepted: 12/05/2021] [Indexed: 11/23/2022]
Abstract
Eukaryotic messenger RNA is translated via a 5' cap-dependent initiation mechanism. Experimental evidence for proteins involved with translation initiation among eukaryotic parasites is lacking, including Plasmodium falciparum, the human malaria parasite. Native P. falciparum proteins from asexual stage parasites were enriched using a 5' cap affinity matrix. Proteomic analysis of enriched protein eluates revealed proteins putatively associated with the 5' cap. The canonical 5' cap-binding protein eIF4E (PF3D7_0315100) was the most reproducibly enriched protein. The eIF4A and eIF4G proteins hypothesized to form the eIF4F initiation complex with eIF4E were also detected as 5' cap enriched, albeit with low reproducibility. Surprisingly, enolase (ENO) was the second most enriched protein after eIF4E. Recombinant ENO protein did not demonstrate 5' cap activity, suggesting an indirect association of the native ENO with the 5' cap.
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Xue C, Gu X, Li G, Bao Z, Li L. Expression and Functional Roles of Eukaryotic Initiation Factor 4A Family Proteins in Human Cancers. Front Cell Dev Biol 2021; 9:711965. [PMID: 34869305 PMCID: PMC8640450 DOI: 10.3389/fcell.2021.711965] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 11/05/2021] [Indexed: 01/11/2023] Open
Abstract
The dysregulation of mRNA translation is common in malignancies and may lead to tumorigenesis and progression. Eukaryotic initiation factor 4A (eIF4A) proteins are essential for translation, exhibit bidirectional RNA helicase function, and act as RNA-dependent ATPases. In this review, we explored the predicted structures of the three eIF4A isoforms (eIF4A1, eIF4A2, and eIF4A3), and discussed possible explanations for which function during different translation stages (initiation, mRNA localization, export, and mRNA splicing). These proteins also frequently served as targets of microRNAs (miRNAs) or long noncoding RNAs (lncRNAs) to mediate epithelial-mesenchymal transition (EMT), which was associated with tumor cell invasion and metastasis. To define the differential expression of eIF4A family members, we applied the Tumor Immune Estimation Resource website. We figured out that the eIF4A family genes were differently expressed in specific cancer types. We also found that the level of the eIF4A family genes were associated with abundant immune cells infiltration and tumor purity. The associations between eIF4A proteins and cancer patient clinicopathological features suggested that eIF4A proteins might serve as biomarkers for early tumor diagnosis, histological classification, and clinical grading/staging, providing new tools for precise and individualized cancer treatment.
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Affiliation(s)
- Chen Xue
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Xinyu Gu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Ganglei Li
- Department of Neurosurgery, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Zhengyi Bao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Lanjuan Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
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High-risk human papillomavirus-18 uses an mRNA sequence to synthesize oncoprotein E6 in tumors. Proc Natl Acad Sci U S A 2021; 118:2108359118. [PMID: 34615711 DOI: 10.1073/pnas.2108359118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2021] [Indexed: 01/20/2023] Open
Abstract
Cervical cancer is the fourth most common cause of cancer in women worldwide in terms of both incidence and mortality. Persistent infection with high-risk types of human papillomavirus (HPV), namely 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68, constitute a necessary cause for the development of cervical cancer. Viral oncoproteins E6 and E7 play central roles in the carcinogenic process by virtue of their interactions with cell master proteins such as p53, retinoblastoma (Rb), mammalian target of rapamycin (mTOR), and c-MYC. For the synthesis of E6 and E7, HPVs use a bicistronic messenger RNA (mRNA) that has been studied in cultured cells. Here, we report that in cervical tumors, HPV-18, -39, and -45 transcribe E6/E7 mRNAs with extremely short 5' untranslated regions (UTRs) or even lacking a 5' UTR (i.e., zero to three nucleotides long) to express E6. We show that the translation of HPV-18 E6 cistron is regulated by the motif ACCaugGCGCG(C/A)UUU surrounding the AUG start codon, which we term Translation Initiation of Leaderless mRNAs (TILM). This motif is conserved in all HPV types of the phylogenetically coherent group forming genus alpha, species 7, which infect mucosal epithelia. We further show that the translation of HPV-18 E6 largely relies on the cap structure and eIF4E and eIF4AI, two key translation initiation factors linking translation and cancer but does not involve scanning. Our results support the notion that E6 forms the center of the positive oncogenic feedback loop node involving eIF4E, the mTOR cascade, and p53.
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Iwao Y, Okamoto Y, Shirahama H, Tsukahara S, Tomida A. eIF4B enhances ATF4 expression and contributes to cellular adaptation to asparagine limitation in BRAF-mutated A375 melanoma. Biochem Biophys Res Commun 2021; 573:93-99. [PMID: 34403810 DOI: 10.1016/j.bbrc.2021.08.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 08/06/2021] [Indexed: 11/16/2022]
Abstract
ATF4 is a crucial transcription factor in the integrated stress response, a major adaptive signaling pathway activated by tumor microenvironment and therapeutic stresses. BRAF inhibitors, such as vemurafenib, induce ATF4 in BRAF-mutated melanoma cells, but the mechanisms of ATF4 induction are not fully elucidated. Here, we show that ATF4 expression can be upregulated by eukaryotic initiation factor 4B (eIF4B) in BRAF-mutated A375 cells. Indeed, eIF4B knockout (KO) prevented ATF4 induction and activation of the uORF-mediated ATF4 translation mechanism during vemurafenib treatment, which were effectively recovered by the rescue of eIF4B. Transcriptome analysis revealed that eIF4B KO selectively influenced ATF4-target gene expression among the overall gene expression changed by vemurafenib. Interestingly, eIF4B supported cellular proliferation under asparagine-limited conditions, possibly through the eIF4B-ATF4 pathway. Our findings indicate that eIF4B can regulate ATF4 expression, thereby contributing to cellular stress adaptation, which could be targeted as a therapeutic approach against malignancies, including melanoma.
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Affiliation(s)
- Yukie Iwao
- Division of Genome Research, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan; Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuka Okamoto
- Division of Genome Research, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan
| | - Hitomi Shirahama
- Division of Genome Research, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan
| | - Satomi Tsukahara
- Division of Genome Research, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan
| | - Akihiro Tomida
- Division of Genome Research, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan; Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan.
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Bhatter N, Iyyappan R, Mohanan G, Rajyaguru PI. Exploring the role of RRM domains and conserved aromatic residues in RGG motif of eIF4G-binding translation repressor protein Sbp1. Wellcome Open Res 2021; 3:102. [PMID: 32175478 PMCID: PMC7059846 DOI: 10.12688/wellcomeopenres.14709.3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/03/2021] [Indexed: 11/20/2022] Open
Abstract
Background: RNA binding proteins play crucial role in determining if a given mRNA will be translated, stored, or degraded. Sbp1 is an RGG-motif containing protein that is implicated in affecting mRNA decapping and translation. Sbp1 represses translation by binding eIF4G1 through its RGG-motif and activates decapping when overexpressed. In this report, we have assessed the genetic interaction of Sbp1 with decapping activators such as Dhh1, Pat1, and Scd6. We have further analyzed the importance of different domains and specific conserved residues of Sbp1 in its ability to cause over-expression mediated growth defect. Method: Sequence alignment was performed to identify conserved aromatic residues to be mutated. Using site-directed mutagenesis several point mutations and domain deletions were created in Sbp1 expressed under a galactose-inducible promoter. The mutants were tested for their ability to cause growth defect upon over-expression. The ability of Sbp1 to affect over-expression mediated growth defect of other decapping activators was tested using growth assay. Live cell imaging was done to study localization of Sbp1 and its RRM-deletion mutants to RNA granules upon glucose starvation. Results: Mutation of several aromatic residues in the RGG-motif and that of the phosphorylation sites in the RRM domain of Sbp1 did not affect the growth defect phenotype. Deletion of another eIF4G1-binding RGG-motif protein Scd6 does not affect the ability of Sbp1 to cause growth defect. Moreover, absence of Sbp1 did not affect the growth defect phenotypes observed upon overexpression of decapping activators Dhh1 and Pat1. Strikingly deletion of both the RRM domains (RRM1 and RRM2) and not the RNP motifs within them compromised the growth defect phenotype. Sbp1 mutant lacking both RRM1 and RRM2 was highly defective in localizing to RNA granules. Conclusion: This study identifies an important role of RRM domains independent of the RNP motif in Sbp1 function.
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Affiliation(s)
- Nupur Bhatter
- Department of Biochemistry, Indian Institute of Science, CV Raman Road, Bangalore, 560012, India
| | - Rajan Iyyappan
- Institute of Animal Physiology and Genetics, Libechov, Czech Republic
| | - Gayatri Mohanan
- Department of Biochemistry, Indian Institute of Science, CV Raman Road, Bangalore, 560012, India
| | - Purusharth I Rajyaguru
- Department of Biochemistry, Indian Institute of Science, CV Raman Road, Bangalore, 560012, India
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EIF3D promotes the progression of preeclampsia by inhibiting of MAPK/ERK1/2 pathway. Reprod Toxicol 2021; 105:166-174. [PMID: 34520790 DOI: 10.1016/j.reprotox.2021.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/19/2021] [Accepted: 09/09/2021] [Indexed: 12/21/2022]
Abstract
Preeclampsia (PE) has been recognized as one of the main reasons for neonatal and maternal mortality and morbidity. This study intended to identify certain genes that correlated with the pathogenesis of PE, and disclose the underlying mechanisms. The GSE14776 and GSE65271 datasets were obtained from the Gene Expression Omnibus database. Venn diagram analysis was performed to identify the differently expressed genes. The potential pathways were analyzed by Gene set enrichment analysis software. The expression of eukaryotic translation initiation factor 3 subunit D (EIF3D) in tissues and cells was respectively tested by immunohistochemistry and the quantitative real-time PCR. Cell transfection was utilized to alter the expression of EIF3D. Cell proliferation, invasion and migration were respectively tested by MTT, EdU, transwell and wound healing assays. Tube formation assay was utilized to determine the tube formation capacity of HTR-8/SVneo cells. ELISA was employed for determination of the concentration of Angiotensin (ANG)-1. Moreover, the expression of EIF3D, proliferation-, metastasis-, tube formation- and MAPK/ERK1/2 pathway-related proteins were measured utilizing western blot. EIF3D was selected in this study. EIF3D was upregulated in placentas tissues collected from patients with PE. EIF3D upregulation observably repressed the proliferation, invasion, migration, wound healing and tube formation of HTR-8/SVneo cells, and the expression of their associated proteins. Besides, the concentration of ANG-1, and the ratios of phosphorylated-ERK1/2 and phosphorylated-MEK1/MEK1 were also markedly lowered by EIF3D upregulation. Whereas, EIF3D knockdown exerted the opposite effects, and these effects were distinctly counteracted by ERK1/2 inhibitor SC-221593 treatment. In conclusion, these observations manifested that EIF3D upregulation might have repressed the progression of PE through modulation of MAPK/ERK1/2 pathway.
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Zhang X, Yin Y, Su Y, Jia Z, Jiang L, Lu Y, Zheng H, Peng J, Rao S, Wu G, Chen J, Yan F. eIF4A, a target of siRNA derived from rice stripe virus, negatively regulates antiviral autophagy by interacting with ATG5 in Nicotiana benthamiana. PLoS Pathog 2021; 17:e1009963. [PMID: 34587220 PMCID: PMC8504976 DOI: 10.1371/journal.ppat.1009963] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 10/11/2021] [Accepted: 09/21/2021] [Indexed: 12/11/2022] Open
Abstract
Autophagy is induced by viral infection and has antiviral functions in plants, but the underlying mechanism is poorly understood. We previously identified a viral small interfering RNA (vsiRNA) derived from rice stripe virus (RSV) RNA4 that contributes to the leaf-twisting and stunting symptoms caused by this virus by targeting the host eukaryotic translation initiation factor 4A (eIF4A) mRNA for silencing. In addition, autophagy plays antiviral roles by degrading RSV p3 protein, a suppressor of RNA silencing. Here, we demonstrate that eIF4A acts as a negative regulator of autophagy in Nicotiana benthamiana. Silencing of NbeIF4A activated autophagy and inhibited RSV infection by facilitating autophagic degradation of p3. Further analysis showed that NbeIF4A interacts with NbATG5 and interferes with its interaction with ATG12. Overexpression of NbeIF4A suppressed NbATG5-activated autophagy. Moreover, expression of vsiRNA-4A, which targets NbeIF4A mRNA for cleavage, induced autophagy by silencing NbeIF4A. Finally, we demonstrate that eIF4A from rice, the natural host of RSV, also interacts with OsATG5 and suppresses OsATG5-activated autophagy, pointing to the conserved function of eIF4A as a negative regulator of antiviral autophagy. Taken together, these results reveal that eIF4A negatively regulates antiviral autophagy by interacting with ATG5 and that its mRNA is recognized by a virus-derived siRNA, resulting in its silencing, which induces autophagy against viral infection.
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Affiliation(s)
- Xiangxiang Zhang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
- Plant Protection College, Yunnan Agricultural University, Kunming, China
| | - Yueyan Yin
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
- Plant Protection College, Yunnan Agricultural University, Kunming, China
| | - Yunhe Su
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Zhaoxing Jia
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Liangliang Jiang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Yuwen Lu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Hongying Zheng
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Jiejun Peng
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Shaofei Rao
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Guanwei Wu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Jianping Chen
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
- Plant Protection College, Yunnan Agricultural University, Kunming, China
- Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Fei Yan
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
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Perzanowska O, Majewski M, Strenkowska M, Głowala P, Czarnocki-Cieciura M, Mazur M, Kowalska J, Jemielity J. Nucleotide-decorated AuNPs as probes for nucleotide-binding proteins. Sci Rep 2021; 11:15741. [PMID: 34344911 PMCID: PMC8333360 DOI: 10.1038/s41598-021-94983-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 07/12/2021] [Indexed: 12/01/2022] Open
Abstract
Gold nanoparticles (AuNPs) decorated with biologically relevant molecules have variety of applications in optical sensing of bioanalytes. Coating AuNPs with small nucleotides produces particles with high stability in water, but functionality-compatible strategies are needed to uncover the full potential of this type of conjugates. Here, we demonstrate that lipoic acid-modified dinucleotides can be used to modify AuNPs surfaces in a controllable manner to produce conjugates that are stable in aqueous buffers and biological mixtures and capable of interacting with nucleotide-binding proteins. Using this strategy we obtained AuNPs decorated with 7-methylguanosine mRNA 5' cap analogs and showed that they bind cap-specific protein, eIF4E. AuNPs decorated with non-functional dinucleotides also interacted with eIF4E, albeit with lower affinity, suggesting that eIF4E binding to cap-decorated AuNPs is partially mediated by unspecific ionic interactions. This issue was overcome by applying lipoic-acid-Tris conjugate as a charge-neutral diluting molecule. Tris-Lipo-diluted cap-AuNPs conjugates interacted with eIF4E in fully specific manner, enabling design of functional tools. To demonstrate the potential of these conjugates in protein sensing, we designed a two-component eIF4E sensing system consisting of cap-AuNP and 4E-BP1-AuNP conjugates, wherein 4E-BP1 is a short peptide derived from 4E-BP protein that specifically binds eIF4E at a site different to that of the 5' cap. This system facilitated controlled aggregation, in which eIF4E plays the role of the agent that crosslinks two types of AuNP, thereby inducing a naked-eye visible absorbance redshift. The reported AuNPs-nucleotide conjugation method based on lipoic acid affinity for gold, can be harnessed to obtain other types of nucleotide-functionalized AuNPs, thereby paving the way to studying other nucleotide-binding proteins.
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Affiliation(s)
- Olga Perzanowska
- Division of Biophysics, Faculty of Physics, University of Warsaw, Ludwika Pasteura 5, 02-093, Warsaw, Poland
- Centre of New Technologies, University of Warsaw, Stefana Banacha 2c, 02-097, Warsaw, Poland
| | - Maciej Majewski
- Division of Biophysics, Faculty of Physics, University of Warsaw, Ludwika Pasteura 5, 02-093, Warsaw, Poland
| | - Malwina Strenkowska
- Division of Biophysics, Faculty of Physics, University of Warsaw, Ludwika Pasteura 5, 02-093, Warsaw, Poland
| | - Paulina Głowala
- Faculty of Chemistry, University of Warsaw, Ludwika Pasteura 1, 02-093, Warsaw, Poland
| | - Mariusz Czarnocki-Cieciura
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Księcia Trojdena 4, 02-109, Warsaw, Poland
| | - Maciej Mazur
- Faculty of Chemistry, University of Warsaw, Ludwika Pasteura 1, 02-093, Warsaw, Poland
| | - Joanna Kowalska
- Division of Biophysics, Faculty of Physics, University of Warsaw, Ludwika Pasteura 5, 02-093, Warsaw, Poland.
| | - Jacek Jemielity
- Centre of New Technologies, University of Warsaw, Stefana Banacha 2c, 02-097, Warsaw, Poland.
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40
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Wu S, Wagner G. Deep computational analysis details dysregulation of eukaryotic translation initiation complex eIF4F in human cancers. Cell Syst 2021; 12:907-923.e6. [PMID: 34358439 DOI: 10.1016/j.cels.2021.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 04/22/2021] [Accepted: 07/09/2021] [Indexed: 12/28/2022]
Abstract
eIF4F plays diverse roles in human cancers, which complicate the development of an overarching understanding of its functional and regulatory impacts across tumor types. Typically, eIF4F drives initiation from the mRNA 5' end (cap) and is composed of eIF4G1, eIF4A1, and cap-binding eIF4E. Cap-independent initiation is possible without eIF4E, from internal ribosomal entry sites (IRESs). By analyzing large public datasets, we found that cancers selectively overexpress EIF4G1 more than EIF4E. That expression imbalance supports EIF4G1 as a prognostic indicator in patients with cancer. It also attenuates "housekeeping" pathways that are usually regulated in a tissue-specific manner via cap-dependent initiation in healthy tissues and reinforce regulation of cancer-preferred pathways in cap-independent contexts. Cap-independent initiation is mechanistically attributable to eIF4G1 hyperphosphorylation that promotes binding to eIF4A1 and reduced eIF4E availability. Collectively, these findings reveal a novel model of dysregulated eIF4F function and highlight the clinical relevance of cap-(in)dependent initiation in cancer.
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Affiliation(s)
- Su Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
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41
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Jensen KB, Dredge BK, Toubia J, Jin X, Iadevaia V, Goodall GJ, Proud CG. capCLIP: a new tool to probe translational control in human cells through capture and identification of the eIF4E-mRNA interactome. Nucleic Acids Res 2021; 49:e105. [PMID: 34255842 PMCID: PMC8501963 DOI: 10.1093/nar/gkab604] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 06/16/2021] [Accepted: 07/06/2021] [Indexed: 12/21/2022] Open
Abstract
Translation of eukaryotic mRNAs begins with binding of their m7G cap to eIF4E, followed by recruitment of other translation initiation factor proteins. We describe capCLIP, a novel method to comprehensively capture and quantify the eIF4E (eukaryotic initiation factor 4E) 'cap-ome' and apply it to examine the biological consequences of eIF4E-cap binding in distinct cellular contexts. First, we use capCLIP to identify the eIF4E cap-omes in human cells with/without the mTORC1 (mechanistic target of rapamycin, complex 1) inhibitor rapamycin, there being an emerging consensus that rapamycin inhibits translation of TOP (terminal oligopyrimidine) mRNAs by displacing eIF4E from their caps. capCLIP reveals that the representation of TOP mRNAs in the cap-ome is indeed systematically reduced by rapamycin, thus validating our new methodology. capCLIP also refines the requirements for a functional TOP sequence. Second, we apply capCLIP to probe the consequences of phosphorylation of eIF4E. We show eIF4E phosphorylation reduces overall eIF4E-mRNA association and, strikingly, causes preferential dissociation of mRNAs with short 5'-UTRs. capCLIP is a valuable new tool to probe the function of eIF4E and of other cap-binding proteins such as eIF4E2/eIF4E3.
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Affiliation(s)
- Kirk B Jensen
- Lifelong Health, South Australian Health and Medical Research Institute, North Terrace, Adelaide, SA 5000, Australia.,School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - B Kate Dredge
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia
| | - John Toubia
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia.,ACRF Cancer Genomics Facility, Centre for Cancer Biology, SA Pathology and University of South Australia, Frome Road, Adelaide, SA 5000, Australia
| | - Xin Jin
- Lifelong Health, South Australian Health and Medical Research Institute, North Terrace, Adelaide, SA 5000, Australia.,School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Valentina Iadevaia
- School of Biosciences and Medicine, University of Surrey, Guildford, Surrey GU2 7XH, UK
| | - Gregory J Goodall
- School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA 5005, Australia.,Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia.,Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Christopher G Proud
- Lifelong Health, South Australian Health and Medical Research Institute, North Terrace, Adelaide, SA 5000, Australia.,School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA 5005, Australia
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42
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Weiss B, Allen GE, Kloehn J, Abid K, Jaquier-Gubler P, Curran JA. eIF4E3 forms an active eIF4F complex during stresses (eIF4FS) targeting mTOR and re-programs the translatome. Nucleic Acids Res 2021; 49:5159-5176. [PMID: 33893802 PMCID: PMC8136781 DOI: 10.1093/nar/gkab267] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/24/2021] [Accepted: 03/31/2021] [Indexed: 12/13/2022] Open
Abstract
The eIF4E are a family of initiation factors that bind the mRNA 5′ cap, regulating the proteome and the cellular phenotype. eIF4E1 mediates global translation and its activity is controlled via the PI3K/AKT/mTOR pathway. mTOR down-regulation results in eIF4E1 sequestration into an inactive complex with the 4E binding proteins (4EBPs). The second member, eIF4E2, regulates the translatome during hypoxia. However, the exact function of the third member, eIF4E3, has remained elusive. We have dissected its function using a range of techniques. Starting from the observation that it does not interact with 4EBP1, we demonstrate that eIF4E3 recruitment into an eIF4F complex occurs when Torin1 inhibits the mTOR pathway. Ribo-seq studies demonstrate that this complex (eIF4FS) is translationally active during stress and that it selects specific mRNA populations based on 5′ TL (UTR) length. The interactome reveals that it associates with cellular proteins beyond the cognate initiation factors, suggesting that it may have ‘moon-lighting’ functions. Finally, we provide evidence that cellular metabolism is altered in an eIF4E3 KO background but only upon Torin1 treatment. We propose that eIF4E3 acts as a second branch of the integrated stress response, re-programming the translatome to promote ‘stress resistance’ and adaptation.
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Affiliation(s)
- Benjamin Weiss
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Switzerland
| | - George Edward Allen
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Switzerland
| | - Joachim Kloehn
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Switzerland
| | - Karim Abid
- Catecholamine and Peptides Laboratory, Service of Clinical Pharmacology, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Pascale Jaquier-Gubler
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Switzerland
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43
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Du J, Jiang L, Chen F, Hu H, Zhou M. Cardiac Glycoside Ouabain Exerts Anticancer Activity via Downregulation of STAT3. Front Oncol 2021; 11:684316. [PMID: 34277430 PMCID: PMC8279743 DOI: 10.3389/fonc.2021.684316] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 06/16/2021] [Indexed: 12/30/2022] Open
Abstract
Cardiac glycosides are plant-derived steroid-like compounds which have been used for the treatment of cardiovascular diseases. Ouabain, a cardiotonic steroid and specific Na+/K+-ATPase inhibitor, has been rediscovered for its potential use in the treatment of cancer. However, the cellular targets and anticancer mechanism of ouabain in various cancers remain largely unexplored. In this study, we confirmed the cytotoxic effects of ouabain on several cancer cell lines. Further examination revealed the increase of apoptosis, intracellular ROS generation and DNA double-strand breaks induced by ouabain treatment. Besides, ouabain effectively suppressed STAT3 expression as well as phosphorylation in addition to block STAT3-mediated transcription and downstream target proteins. Interestingly, these inhibitory activities seemed to be independent of the Na+/K+-ATPase. Furthermore, we found that ouabain inhibited protein synthesis through regulation of the eukaryotic initiation factor 4E (eIF4E) and eIF4E binding protein 1 (4EBP1). Taken together, our study provided a novel molecular insight of anticancer activities of ouabain in human cancer cells, which could raise the hope of using cardiac glycosides for cancer therapeutics more rational.
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Affiliation(s)
- Jie Du
- Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun Yat-sen University, Jiangmen, China.,Department of Radiation Medicine, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
| | - Lijun Jiang
- Department of Radiation Medicine, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
| | - Fuqiang Chen
- Department of Radiation Medicine, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
| | - Huantao Hu
- The First School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Meijuan Zhou
- Department of Radiation Medicine, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
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44
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DEAD-Box RNA Helicases in Cell Cycle Control and Clinical Therapy. Cells 2021; 10:cells10061540. [PMID: 34207140 PMCID: PMC8234093 DOI: 10.3390/cells10061540] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/11/2021] [Accepted: 06/15/2021] [Indexed: 12/11/2022] Open
Abstract
Cell cycle is regulated through numerous signaling pathways that determine whether cells will proliferate, remain quiescent, arrest, or undergo apoptosis. Abnormal cell cycle regulation has been linked to many diseases. Thus, there is an urgent need to understand the diverse molecular mechanisms of how the cell cycle is controlled. RNA helicases constitute a large family of proteins with functions in all aspects of RNA metabolism, including unwinding or annealing of RNA molecules to regulate pre-mRNA, rRNA and miRNA processing, clamping protein complexes on RNA, or remodeling ribonucleoprotein complexes, to regulate gene expression. RNA helicases also regulate the activity of specific proteins through direct interaction. Abnormal expression of RNA helicases has been associated with different diseases, including cancer, neurological disorders, aging, and autosomal dominant polycystic kidney disease (ADPKD) via regulation of a diverse range of cellular processes such as cell proliferation, cell cycle arrest, and apoptosis. Recent studies showed that RNA helicases participate in the regulation of the cell cycle progression at each cell cycle phase, including G1-S transition, S phase, G2-M transition, mitosis, and cytokinesis. In this review, we discuss the essential roles and mechanisms of RNA helicases in the regulation of the cell cycle at different phases. For that, RNA helicases provide a rich source of targets for the development of therapeutic or prophylactic drugs. We also discuss the different targeting strategies against RNA helicases, the different types of compounds explored, the proposed inhibitory mechanisms of the compounds on specific RNA helicases, and the therapeutic potential of these compounds in the treatment of various disorders.
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45
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Alard A, Strehaïano M, Müller D, Lasfargues C, Cassant-Sourdy S, Jean C, Bousquet C, Martineau Y, Pyronnet S. Phosphorylation of the MNK1 substrate eIF4E is not required for response to acute pancreatitis. Pancreatology 2021; 21:677-681. [PMID: 33648878 DOI: 10.1016/j.pan.2021.02.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/21/2021] [Accepted: 02/10/2021] [Indexed: 12/11/2022]
Abstract
BACKGROUND The MNK1 protein kinase is directly activated by the MAPK pathway and is specifically expressed in pancreatic acinar cells. Both the MNK1 kinase and the MAPK pathway are required for response to pancreatitis, suggesting that their pharmacological targeting would be of therapeutic interest. Because the mRNA cap-binding protein and translation initiation factor eIF4E is the major known MNK1 substrate, one could anticipate that the protective function of MNK1 in pancreatitis is mediated by eIF4E phosphorylation. METHODS Acute pancreatitis was induced by the intraperitoneal administration of cerulein in wild-type mice and in transgenic mice carrying two non-phosphorylatable Eif4e alleles. The expression and phosphorylation of proteins of the MNK1-eIF4E pathway was visualized by western-blotting. The severity of pancreatitis was monitored by the measure of serum amylase levels and by histopathology and immunohistochemistry using apoptosis and immune infiltrate markers. RESULTS Despite a strong induction in MNK1 kinase activity in both wild-type and transgenic mice, precluding eIF4E phosphorylation has no impact on the severity of acute pancreatitis. Serum amylase is equally induced in both mouse genotypes and neither acinar cell apoptosis nor immune infiltrate is exacerbated. CONCLUSION eIF4E phosphorylation is not required for response to pancreatitis indicating that the acinar-cell-specific MNK1 kinase acts in acute pancreatitis via another substrate.
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Affiliation(s)
- Amandine Alard
- INSERM UMR-1037, Université de Toulouse, Centre de Recherches en Cancérologie de Toulouse (CRCT), Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Toulouse, France
| | - Manon Strehaïano
- INSERM UMR-1037, Université de Toulouse, Centre de Recherches en Cancérologie de Toulouse (CRCT), Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Toulouse, France
| | - David Müller
- INSERM UMR-1037, Université de Toulouse, Centre de Recherches en Cancérologie de Toulouse (CRCT), Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Toulouse, France
| | - Charline Lasfargues
- INSERM UMR-1037, Université de Toulouse, Centre de Recherches en Cancérologie de Toulouse (CRCT), Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Toulouse, France
| | - Stéphanie Cassant-Sourdy
- INSERM UMR-1037, Université de Toulouse, Centre de Recherches en Cancérologie de Toulouse (CRCT), Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Toulouse, France
| | - Christine Jean
- INSERM UMR-1037, Université de Toulouse, Centre de Recherches en Cancérologie de Toulouse (CRCT), Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Toulouse, France
| | - Corinne Bousquet
- INSERM UMR-1037, Université de Toulouse, Centre de Recherches en Cancérologie de Toulouse (CRCT), Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Toulouse, France
| | - Yvan Martineau
- INSERM UMR-1037, Université de Toulouse, Centre de Recherches en Cancérologie de Toulouse (CRCT), Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Toulouse, France
| | - Stéphane Pyronnet
- INSERM UMR-1037, Université de Toulouse, Centre de Recherches en Cancérologie de Toulouse (CRCT), Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Toulouse, France.
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46
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Hong HJ, Guevara MG, Lin E, O'Leary SE. Single-Molecule Dynamics of SARS-CoV-2 5' Cap Recognition by Human eIF4F. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021. [PMID: 34075378 DOI: 10.1101/2021.05.26.445185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Coronaviruses initiate translation through recognition of the viral RNA 5' m 7 GpppA m cap by translation factor eIF4F. eIF4F is a heterotrimeric protein complex with cap-binding, RNA-binding, and RNA helicase activities. Modulating eIF4F function through cellular regulation or small-molecule inhibition impacts coronavirus replication, including for SARS-CoV-2. Translation initiation involves highly coordinated dynamics of translation factors with messenger or viral RNA. However, how the eIF4F subunits coordinate on the initiation timescale to define cap-binding efficiency remains incompletely understood. Here we report that translation supported by the SARS-CoV-2 5'-UTR is highly sensitive to eIF4A inhibition by rocaglamide. Through a single-molecule fluorescence approach that reports on eIF4E-cap interaction, we dissect how eIF4F subunits contribute to cap-recognition efficiency on the SARS-CoV-2 5' UTR. We find that free eIF4A enhances cap accessibility for eIF4E binding, but eIF4G alone does not change the kinetics of eIF4E-RNA interaction. Conversely, formation of the full eIF4F complex significantly alters eIF4E-cap interaction, suggesting that coordinated eIF4E and eIF4A activities establish the net eIF4F-cap recognition efficiency. Moreover, the eIF4F complex formed with phosphomimetic eIF4E(S209D) binds the viral UTR more efficiently than with wild-type eIF4E. These results highlight a dynamic interplay of eIF4F subunits and mRNA that determines cap-recognition efficiency.
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47
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de Lima GB, de Lima Cavalcanti TYV, de Brito ANALM, de Assis LA, Andrade-Vieira RP, Freire ER, da Silva Assunção TR, de Souza Reis CR, Zanchin NIT, Guimarães BG, de-Melo-Neto OP. The translation initiation factor EIF4E5 from Leishmania: crystal structure and interacting partners. RNA Biol 2021; 18:2433-2449. [PMID: 33945405 DOI: 10.1080/15476286.2021.1918919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
The mRNA cap-binding protein, eIF4E, mediates the recognition of the mRNA 5' end and, as part of the heterotrimeric eIF4F complex, facilitates the recruitment of the ribosomal subunits to initiate eukaryotic translation. Various regulatory events involving eIF4E and a second eIF4F subunit, eIF4G, are required for proper control of translation initiation. In pathogenic trypanosomatids, six eIF4Es and five eIF4Gs have been described, several forming different eIF4F-like complexes with yet unresolved roles. EIF4E5 is one of the least known of the trypanosomatid eIF4Es and has not been characterized in Leishmania species. Here, we used immunoprecipitation assays, combined with mass-spectrometry, to identify major EIF4E5 interacting proteins in L. infantum. A constitutively expressed, HA-tagged, EIF4E5 co-precipitated mainly with EIF4G1 and binding partners previously described in Trypanosoma brucei, EIF4G1-IP, RBP43 and the 14-3-3 proteins. In contrast, no clear co-precipitation with EIF4G2, also previously reported, was observed. EIF4E5 also co-precipitated with protein kinases, possibly associated with cell-cycle regulation, selected RNA binding proteins and histones. Phosphorylated residues were identified and mapped to the Leishmania-specific C-terminal end. Mutagenesis of the tryptophan residue (W53) postulated to mediate interactions with protein partners or of a neighbouring tryptophan conserved in Leishmania (W45) did not substantially impair the identified interactions. Finally, the crystal structure of Leishmania EIF4E5 evidences remarkable differences in the eIF4G interfacing region, when compared with human eIF4E-1 and with its Trypanosoma orthologue. Mapping of its C-terminal end near the cap-binding site also imply relevant differences in cap-binding function and/or regulation.
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Affiliation(s)
- Gustavo Barbosa de Lima
- Departamento de Microbiologia, Instituto Aggeu Magalhães, FIOCRUZ-PE, Av. Moraes Rego s/n, Recife-PE, Brazil
| | - Thaíse Yasmine Vasconcelos de Lima Cavalcanti
- Departamento de Microbiologia, Instituto Aggeu Magalhães, FIOCRUZ-PE, Av. Moraes Rego s/n, Recife-PE, Brazil.,Programa de Pós-Graduação em Genética, Universidade Federal de Pernambuco, Recife-PE, Brazil
| | - Adriana Neuman Albuquerque Lins Moura de Brito
- Departamento de Microbiologia, Instituto Aggeu Magalhães, FIOCRUZ-PE, Av. Moraes Rego s/n, Recife-PE, Brazil.,Programa de Pós-Graduação em Genética, Universidade Federal de Pernambuco, Recife-PE, Brazil
| | - Ludmilla Arruda de Assis
- Departamento de Microbiologia, Instituto Aggeu Magalhães, FIOCRUZ-PE, Av. Moraes Rego s/n, Recife-PE, Brazil
| | | | - Eden Ribeiro Freire
- Departamento de Microbiologia, Instituto Aggeu Magalhães, FIOCRUZ-PE, Av. Moraes Rego s/n, Recife-PE, Brazil.,Laboratório de Biologia Estrutural e Engenharia de Proteínas, Instituto Carlos Chagas, FIOCRUZ-PR, Curitiba-PR, Brazil
| | | | | | - Nilson Ivo Tonin Zanchin
- Laboratório de Biologia Estrutural e Engenharia de Proteínas, Instituto Carlos Chagas, FIOCRUZ-PR, Curitiba-PR, Brazil
| | - Beatriz Gomes Guimarães
- Laboratório de Biologia Estrutural e Engenharia de Proteínas, Instituto Carlos Chagas, FIOCRUZ-PR, Curitiba-PR, Brazil
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Lee EJ, Neppl RL. Influence of Age on Skeletal Muscle Hypertrophy and Atrophy Signaling: Established Paradigms and Unexpected Links. Genes (Basel) 2021; 12:genes12050688. [PMID: 34063658 PMCID: PMC8147613 DOI: 10.3390/genes12050688] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 12/16/2022] Open
Abstract
Skeletal muscle atrophy in an inevitable occurrence with advancing age, and a consequence of disease including cancer. Muscle atrophy in the elderly is managed by a regimen of resistance exercise and increased protein intake. Understanding the signaling that regulates muscle mass may identify potential therapeutic targets for the prevention and reversal of muscle atrophy in metabolic and neuromuscular diseases. This review covers the major anabolic and catabolic pathways that regulate skeletal muscle mass, with a focus on recent progress and potential new players.
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49
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Paudel DB, Sanfaçon H. Mapping of sequences in the 5' region and 3' UTR of tomato ringspot virus RNA2 that facilitate cap-independent translation of reporter transcripts in vitro. PLoS One 2021; 16:e0249928. [PMID: 33836032 PMCID: PMC8034749 DOI: 10.1371/journal.pone.0249928] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 03/26/2021] [Indexed: 12/18/2022] Open
Abstract
Tomato ringspot virus (ToRSV, genus Nepovirus, family Secoviridae, order Picornavirales) is a bipartite positive-strand RNA virus, with each RNA encoding one large polyprotein. ToRSV RNAs are linked to a 5'-viral genome-linked protein (VPg) and have a 3' polyA tail, suggesting a non-canonical cap-independent translation initiation mechanism. The 3' untranslated regions (UTRs) of RNA1 and RNA2 are unusually long (~1.5 kb) and share several large stretches of sequence identities. Several putative in-frame start codons are present in the 5' regions of the viral RNAs, which are also highly conserved between the two RNAs. Using reporter transcripts containing the 5' region and 3' UTR of the RNA2 of ToRSV Rasp1 isolate (ToRSV-Rasp1) and in vitro wheat germ extract translation assays, we provide evidence that translation initiates exclusively at the first AUG, in spite of a poor codon context. We also show that both the 5' region and 3' UTR of RNA2 are required for efficient cap-independent translation of these transcripts. We identify translation-enhancing elements in the 5' proximal coding region of the RNA2 polyprotein and in the RNA2 3' UTR. Cap-dependent translation of control reporter transcripts was inhibited when RNAs consisting of the RNA2 3' UTR were supplied in trans. Taken together, our results suggest the presence of a CITE in the ToRSV-Rasp1 RNA2 3' UTR that recruits one or several translation factors and facilitates efficient cap-independent translation together with the 5' region of the RNA. Non-overlapping deletion mutagenesis delineated the putative CITE to a 200 nts segment (nts 773-972) of the 1547 nt long 3' UTR. We conclude that the general mechanism of ToRSV RNA2 translation initiation is similar to that previously reported for the RNAs of blackcurrant reversion virus, another nepovirus. However, the position, sequence and predicted structures of the translation-enhancing elements differed between the two viruses.
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Affiliation(s)
- Dinesh Babu Paudel
- Department of Botany, University of British Columbia, Vancouver, BC, Canada
| | - Hélène Sanfaçon
- Summerland Research and Development Centre, Agriculture and Agri-Food Canada, Summerland, BC, Canada
- * E-mail:
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50
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Hernández-Alvarez L, Oliveira AB, Hernández-González JE, Chahine J, Pascutti PG, de Araujo AS, de Souza FP. Computational study on the allosteric mechanism of Leishmania major IF4E-1 by 4E-interacting protein-1: Unravelling the determinants of m 7GTP cap recognition. Comput Struct Biotechnol J 2021; 19:2027-2044. [PMID: 33995900 PMCID: PMC8085901 DOI: 10.1016/j.csbj.2021.03.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 03/25/2021] [Accepted: 03/29/2021] [Indexed: 02/07/2023] Open
Abstract
Atomistic details on perturbations induced by Lm4E-IP1 binding are described. The modulation of LmIF4E-1 affinity for the cap is confirmed by energetic analyses. Signaling paths between the allosteric and othosteric sites of LmIF4E-1 are predicted. Lm4E-IP1 binding increases the side-chain entropy of W83 and R172 of LmIF4E-1. A mechanism of dynamic allostery is proposed for the regulation mediated by Lm4E-IP1.
During their life cycle, Leishmania parasites display a fine-tuned regulation of the mRNA translation through the differential expression of isoforms of eukaryotic translation initiation factor 4E (LeishIF4Es). The interaction between allosteric modulators such as 4E-interacting proteins (4E-IPs) and LeishIF4E affects the affinity of this initiation factor for the mRNA cap. Here, several computational approaches were employed to elucidate the molecular bases of the previously-reported allosteric modulation in L. major exerted by 4E-IP1 (Lm4E-IP1) on eukaryotic translation initiation factor 4E 1 (LmIF4E-1). Molecular dynamics (MD) simulations and accurate binding free energy calculations (ΔGbind) were combined with network-based modeling of residue-residue correlations. We also describe the differences in internal motions of LmIF4E-1 apo form, cap-bound, and Lm4E-IP1-bound systems. Through community network calculations, the differences in the allosteric pathways of allosterically-inhibited and active forms of LmIF4E-1 were revealed. The ΔGbind values show significant differences between the active and inhibited systems, which are in agreement with the available experimental data. Our study thoroughly describes the dynamical perturbations of LmIF4E-1 cap-binding site triggered by Lm4E-IP1. These findings are not only essential for the understanding of a critical process of trypanosomatids’ gene expression but also for gaining insight into the allostery of eukaryotic IF4Es, which could be useful for structure-based design of drugs against this protein family.
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Affiliation(s)
- Lilian Hernández-Alvarez
- Department of Physics, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista Julio de Mesquita Filho, São José do Rio Preto, São Paulo, Brazil
| | - Antonio B Oliveira
- Department of Physics, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista Julio de Mesquita Filho, São José do Rio Preto, São Paulo, Brazil.,Center for Theoretical Biological Physics, Rice University, Huston, TX, United States
| | - Jorge Enrique Hernández-González
- Department of Physics, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista Julio de Mesquita Filho, São José do Rio Preto, São Paulo, Brazil.,Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Jorge Chahine
- Department of Physics, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista Julio de Mesquita Filho, São José do Rio Preto, São Paulo, Brazil
| | - Pedro Geraldo Pascutti
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Alexandre Suman de Araujo
- Department of Physics, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista Julio de Mesquita Filho, São José do Rio Preto, São Paulo, Brazil
| | - Fátima Pereira de Souza
- Department of Physics, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista Julio de Mesquita Filho, São José do Rio Preto, São Paulo, Brazil
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