1
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Sedor SF, Shao S. Mechanism of ASF1 Inhibition by CDAN1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.08.607204. [PMID: 39149339 PMCID: PMC11326237 DOI: 10.1101/2024.08.08.607204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Codanin-1 (CDAN1) is an essential and ubiquitous protein named after congenital dyserythropoietic anemia type I (CDA-I), an autosomal recessive disease that manifests from mutations in the CDAN1 or CDIN1 ( CD AN1 interacting n uclease 1) gene. CDAN1 interacts with CDIN1 and the paralogous histone H3-H4 chaperones ASF1A ( A nti- S ilencing F unction 1A) and ASF1B, but its function remains unclear. Here, we biochemically and structurally analyze CDAN1 complexes. We find that CDAN1 dimerizes and assembles into cytosolic complexes with CDIN1 and multiple copies of ASF1A/B. Single-particle cryogenic electron microscopy (cryo-EM) structures of CDAN1 complexes identify interactions with ASF1 mediated by two CDAN1 B-domains commonly found in ASF1 binding partners and two helices that mimic histone H3 binding. We additionally observe that one CDAN1 can recruit two ASF1 molecules and that ASF1A and ASF1B have different requirements for CDAN1 engagement. Our findings explain how CDAN1 sequesters and inhibits the chaperone function of ASF1A/B and provide new molecular-level insights into this enigmatic complex.
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Affiliation(s)
- Samantha F. Sedor
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Sichen Shao
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
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2
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Lei Y, Onaka H, Asamizu S. Transcriptionally induced nucleoid-associated protein-like ccr1 in combined-culture serves as a global effector of Streptomyces secondary metabolism. Front Microbiol 2024; 15:1422977. [PMID: 39070263 PMCID: PMC11272600 DOI: 10.3389/fmicb.2024.1422977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Accepted: 06/26/2024] [Indexed: 07/30/2024] Open
Abstract
Combined-cultures involving mycolic acid-containing bacteria (MACB) can stimulate secondary metabolite (SM) production in actinomycetes. In a prior investigation, we screened Streptomyces coelicolor JCM4020 mutants with diminished production of SMs, specifically undecylprodigiosin (RED), which was enhanced by introducing the MACB Tsukamurella pulmonis TP-B0596. In this study, we conducted mutational analysis that pinpointed the sco1842 gene, which we assigned the gene name ccr1 (combined-culture related regulatory protein no. 1), as a crucial factor in the deficient phenotype observed in the production of various major SMs in S. coelicolor A3(2). Notably, the Ccr1 (SCO1842) homolog was found to be highly conserved throughout the Streptomyces genome. Although Ccr1 lacked conserved motifs, in-depth examination revealed the presence of a helix-turn-helix (HTH) motif in the N-terminal region and a helicase C-terminal domain (HCTD) motif in the C-terminal region in some of its homologs. Ccr1 was predicted to be a nucleoid-associated protein (NAP), and its impact on gene transcription was validated by RNA-seq analysis that revealed genome-wide variations. Furthermore, RT-qPCR demonstrated that ccr1 was transcriptionally activated in combined-culture with T. pulmonis, which indicated that Ccr1 is involved in the response to bacterial interaction. We then investigated Streptomyces nigrescens HEK616 in combined-culture, and the knockout mutant of the ccr1 homolog displayed reduced production of streptoaminals and 5aTHQs. This finding reveals that the Ccr1 homolog in Streptomyces species is associated with SM production. Our study elucidates the existence of a new family of NAP-like proteins that evolved in Streptomyces species and play a pivotal role in SM production.
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Affiliation(s)
- Yukun Lei
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Hiroyasu Onaka
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan
- Department of Life Science, Faculty of Science, Gakushuin University, Tokyo, Japan
| | - Shumpei Asamizu
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan
- Engineering Biology Research Center, Kobe University, Kobe, Japan
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3
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Wackowski K, Zhu X, Shen S, Zhang M, Qu J, Read LK. RESC14 and RESC8 cooperate to mediate RESC function and dynamics during trypanosome RNA editing. Nucleic Acids Res 2024:gkae561. [PMID: 38967000 DOI: 10.1093/nar/gkae561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 05/16/2024] [Accepted: 06/18/2024] [Indexed: 07/06/2024] Open
Abstract
Mitochondrial transcripts in Trypanosoma brucei require extensive uridine insertion/deletion RNA editing to generate translatable open reading frames. The RNA editing substrate binding complex (RESC) serves as the scaffold that coordinates the protein-protein and protein-RNA interactions during editing. RESC broadly contains two modules termed the guide RNA binding complex (GRBC) and the RNA editing mediator complex (REMC), as well as organizer proteins. How the protein and RNA components of RESC dynamically interact to facilitate editing is not well understood. Here, we examine the roles of organizer proteins, RESC8 and RESC14, in facilitating RESC dynamics. High-throughput sequencing of editing intermediates reveals an overlapping RESC8 and RESC14 function during editing progression across multiple transcripts. Blue native PAGE analysis demonstrates that RESC14 is essential for incorporation of RESC8 into a large RNA-containing complex, while RESC8 is important in recruiting a smaller ribonucleoprotein complex (RNP) to this large complex. Proximity labeling shows that RESC14 is important for stable RESC protein-protein interactions, as well as RESC-RECC associations. Together, our data support a model in which RESC14 is necessary for assembly of editing competent RESC through recruitment of an RNP containing RESC8, GRBC and gRNA to REMC and mRNA.
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Affiliation(s)
- Katherine Wackowski
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
| | - Xiaoyu Zhu
- Department of Pharmaceutical Sciences, University at Buffalo, Buffalo, NY 14214, USA and NYS Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Shichen Shen
- Department of Pharmaceutical Sciences, University at Buffalo, Buffalo, NY 14214, USA and NYS Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Ming Zhang
- Department of Pharmaceutical Sciences, University at Buffalo, Buffalo, NY 14214, USA and NYS Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Jun Qu
- Department of Pharmaceutical Sciences, University at Buffalo, Buffalo, NY 14214, USA and NYS Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Laurie K Read
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
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4
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Zheng X, Shen J, Jiang H, Tian M, Wang Q, Guo K, Chen R, Xia Q, Yan Q, Du L, Duan S. Exploring the multifaceted role of GCN1: Implications in cellular responses and disease pathogenesis. Biomed Pharmacother 2024; 175:116681. [PMID: 38705128 DOI: 10.1016/j.biopha.2024.116681] [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: 02/04/2024] [Revised: 04/21/2024] [Accepted: 04/29/2024] [Indexed: 05/07/2024] Open
Abstract
GCN1 is a highly conserved protein present widely across eukaryotes. As an upstream activator of protein kinase GCN2, GCN1 plays a pivotal role in integrated stress responses, such as amino acid starvation and oxidative stress. Through interaction with GCN2, GCN1 facilitates the activation of GCN2, thus initiating downstream signaling cascades in response to cellular stressors. In these contexts, the activation of GCN2 necessitates the presence and action of GCN1. Notably, GCN1 also operates as a ribosome collision sensor, contributing significantly to the translation quality control pathway. These discoveries offer valuable insights into cellular responses to internal stresses, vital for maintaining cellular homeostasis. Additionally, GCN1 exhibits the ability to regulate the cell cycle and suppress inflammation, among other processes, independently of GCN2. Our review outlines the structural characteristics and biological functions of GCN1, shedding light on its significant involvement in the onset and progression of various cancer and non-cancer diseases. Our work underscores the role of GCN1 in the context of drug therapeutic effects, hinting at its potential as a promising drug target. Furthermore, our work delves deep into the functional mechanisms of GCN1, promising innovative avenues for the diagnosis and treatment of diseases in the future. The exploration of GCN1's multifaceted roles not only enhances our understanding of its mechanisms but also paves the way for novel therapeutic interventions. The ongoing quest to unveil additional functions of GCN1 holds the promise of further enriching our comprehension of its mode of action.
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Affiliation(s)
- Xinying Zheng
- College of Pharmacy, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China; Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China
| | - Jinze Shen
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China
| | - Hongting Jiang
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China
| | - Mei Tian
- College of Pharmacy, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China; Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China; Geriatric Medicine Center, Department of Endocrinology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical College, Hangzhou, Zhejiang 310014, China
| | - Qurui Wang
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China
| | - Kailin Guo
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China
| | - Ruixiu Chen
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China
| | - Qing Xia
- College of Pharmacy, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China; Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China
| | - Qibin Yan
- College of Pharmacy, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China; Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China
| | - Lihua Du
- College of Pharmacy, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China
| | - Shiwei Duan
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang 310015, China.
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5
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Gotoh S, Mori K, Fujino Y, Kawabe Y, Yamashita T, Omi T, Nagata K, Tagami S, Nagai Y, Ikeda M. eIF5 stimulates the CUG initiation of RAN translation of poly-GA dipeptide repeat protein (DPR) in C9orf72 FTLD/ALS. J Biol Chem 2024; 300:105703. [PMID: 38301895 PMCID: PMC10904283 DOI: 10.1016/j.jbc.2024.105703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 01/20/2024] [Accepted: 01/23/2024] [Indexed: 02/03/2024] Open
Abstract
Tandem GGGGCC repeat expansion in C9orf72 is a genetic cause of frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Transcribed repeats are translated into dipeptide repeat proteins via repeat-associated non-AUG (RAN) translation. However, the regulatory mechanism of RAN translation remains unclear. Here, we reveal a GTPase-activating protein, eukaryotic initiation factor 5 (eIF5), which allosterically facilitates the conversion of eIF2-bound GTP into GDP upon start codon recognition, as a novel modifier of C9orf72 RAN translation. Compared to global translation, eIF5, but not its inactive mutants, preferentially stimulates poly-GA RAN translation. RAN translation is increased during integrated stress response, but the stimulatory effect of eIF5 on poly-GA RAN translation was additive to the increase of RAN translation during integrated stress response, with no further increase in phosphorylated eIF2α. Moreover, an alteration of the CUG near cognate codon to CCG or AUG in the poly-GA reading frame abolished the stimulatory effects, indicating that eIF5 primarily acts through the CUG-dependent initiation. Lastly, in a Drosophila model of C9orf72 FTLD/ALS that expresses GGGGCC repeats in the eye, knockdown of endogenous eIF5 by two independent RNAi strains significantly reduced poly-GA expressions, confirming in vivo effect of eIF5 on poly-GA RAN translation. Together, eIF5 stimulates the CUG initiation of poly-GA RAN translation in cellular and Drosophila disease models of C9orf72 FTLD/ALS.
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Affiliation(s)
- Shiho Gotoh
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Japan
| | - Kohji Mori
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Japan.
| | - Yuzo Fujino
- Department of Neurology, Kindai University Faculty of Medicine, Osaka-Sayama, Japan; Department of Neurology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yuya Kawabe
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Japan
| | - Tomoko Yamashita
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Japan
| | - Tsubasa Omi
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Japan
| | - Kenichi Nagata
- Department of Precision Medicine for Dementia, Osaka University Graduate School of Medicine, Suita, Japan
| | - Shinji Tagami
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yoshitaka Nagai
- Department of Neurology, Kindai University Faculty of Medicine, Osaka-Sayama, Japan
| | - Manabu Ikeda
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Japan
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6
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Lamsal M, Luker HA, Pinch M, Hansen IA. RNAi-Mediated Knockdown of Acidic Ribosomal Stalk Protein P1 Arrests Egg Development in Adult Female Yellow Fever Mosquitoes, Aedes aegypti. INSECTS 2024; 15:84. [PMID: 38392504 PMCID: PMC10889338 DOI: 10.3390/insects15020084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/10/2024] [Accepted: 01/20/2024] [Indexed: 02/24/2024]
Abstract
After taking a blood meal, the fat body of the adult female yellow fever mosquito, Aedes aegypti, switches from a previtellogenic state of arrest to an active state of synthesizing large quantities of yolk protein precursors (YPPs) that are crucial for egg development. The synthesis of YPPs is regulated at both the transcriptional and translational levels. Previously, we identified the cytoplasmic protein general control nonderepressible 1 (GCN1) as a part of the translational regulatory pathway for YPP synthesis. In the current study, we used the C-terminal end of GCN1 to screen for protein-protein interactions and identified 60S acidic ribosomal protein P1 (P1). An expression analysis and RNAi-mediated knockdown of P1 was performed to further investigate the role of P1 in mosquito reproduction. We showed that in unfed (absence of a blood meal) adult A. aegypti mosquitoes, P1 was expressed ubiquitously in the mosquito organs and tissues tested. We also showed that the RNAi-mediated knockdown of P1 in unfed adult female mosquitoes resulted in a strong, transient knockdown with observable phenotypic changes in ovary length and egg deposition. Our results suggest that 60S acidic ribosomal protein P1 is necessary for mosquito reproduction and is a promising target for mosquito population control.
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Affiliation(s)
- Mahesh Lamsal
- Molecular Vector Physiology Laboratory, Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
| | - Hailey A Luker
- Molecular Vector Physiology Laboratory, Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
| | - Matthew Pinch
- Department of Biology, University of Texas El Paso, El Paso, TX 79968, USA
| | - Immo A Hansen
- Molecular Vector Physiology Laboratory, Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
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7
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Davarinejad H, Arvanitis-Vigneault A, Nygard D, Lavallée-Adam M, Couture JF. Modus operandi: Chromatin recognition by α-helical histone readers. Structure 2024; 32:8-17. [PMID: 37922903 DOI: 10.1016/j.str.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 09/25/2023] [Accepted: 10/10/2023] [Indexed: 11/07/2023]
Abstract
Histone reader domains provide a mechanism for sensing states of coordinated nuclear processes marked by histone proteins' post-translational modifications (PTMs). Among a growing number of discovered histone readers, the 14-3-3s, ankyrin repeat domains (ARDs), tetratricopeptide repeats (TPRs), bromodomains (BRDs), and HEAT domains are a group of domains using various mechanisms to recognize unmodified or modified histones, yet they all are composed of an α-helical fold. In this review, we compare how these readers fold to create protein domains that are very diverse in their tertiary structures, giving rise to intriguing peptide binding mechanisms resulting in vastly different footprints of their targets.
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Affiliation(s)
- Hossein Davarinejad
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Alexis Arvanitis-Vigneault
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Dallas Nygard
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Mathieu Lavallée-Adam
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Jean-François Couture
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada.
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8
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Shestakova ED, Tumbinsky RS, Andreev DE, Rozov FN, Shatsky IN, Terenin IM. The Roles of eIF4G2 in Leaky Scanning and Reinitiation on the Human Dual-Coding POLG mRNA. Int J Mol Sci 2023; 24:17149. [PMID: 38138978 PMCID: PMC10742948 DOI: 10.3390/ijms242417149] [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] [Revised: 11/29/2023] [Accepted: 12/01/2023] [Indexed: 12/24/2023] Open
Abstract
Upstream open reading frames (uORFs) are a frequent feature of eukaryotic mRNAs. Upstream ORFs govern main ORF translation in a variety of ways, but, in a nutshell, they either filter out scanning ribosomes or allow downstream translation initiation via leaky scanning or reinitiation. Previous reports concurred that eIF4G2, a long-known but insufficiently studied eIF4G1 homologue, can rescue the downstream translation, but disagreed on whether it is leaky scanning or reinitiation that eIF4G2 promotes. Here, we investigated a unique human mRNA that encodes two highly conserved proteins (POLGARF with unknown function and POLG, the catalytic subunit of the mitochondrial DNA polymerase) in overlapping reading frames downstream of a regulatory uORF. We show that the uORF renders the translation of both POLGARF and POLG mRNAs reliant on eIF4G2. Mechanistically, eIF4G2 enhances both leaky scanning and reinitiation, and it appears that ribosomes can acquire eIF4G2 during the early steps of reinitiation. This emphasizes the role of eIF4G2 as a multifunctional scanning guardian that replaces eIF4G1 to facilitate ribosome movement but not ribosome attachment to an mRNA.
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Affiliation(s)
- Ekaterina D. Shestakova
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119234 Moscow, Russia (R.S.T.)
| | - Roman S. Tumbinsky
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119234 Moscow, Russia (R.S.T.)
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia (I.N.S.)
| | - Dmitri E. Andreev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia (I.N.S.)
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, RAS, 117997 Moscow, Russia
| | - Fedor N. Rozov
- Department of Biochemistry, School of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Ivan N. Shatsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia (I.N.S.)
| | - Ilya M. Terenin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia (I.N.S.)
- Translational Medicine Research Center, Sirius University of Science and Technology, Olimpiyskiy ave. b.1, 354349 Sochi, Russia
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9
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Imai S, Suzuki H, Fujiyoshi Y, Shimada I. Dynamically regulated two-site interaction of viral RNA to capture host translation initiation factor. Nat Commun 2023; 14:4977. [PMID: 37640715 PMCID: PMC10462655 DOI: 10.1038/s41467-023-40582-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 07/27/2023] [Indexed: 08/31/2023] Open
Abstract
Many RNA viruses employ internal ribosome entry sites (IRESs) in their genomic RNA to commandeer the host's translational machinery for replication. The IRES from encephalomyocarditis virus (EMCV) interacts with eukaryotic translation initiation factor 4 G (eIF4G), recruiting the ribosomal subunit for translation. Here, we analyze the three-dimensional structure of the complex composed of EMCV IRES, the HEAT1 domain fragment of eIF4G, and eIF4A, by cryo-electron microscopy. Two distinct eIF4G-interacting domains on the IRES are identified, and complex formation changes the angle therebetween. Further, we explore the dynamics of these domains by using solution NMR spectroscopy, revealing conformational equilibria in the microsecond to millisecond timescale. In the lowly-populated conformations, the base-pairing register of one domain is shifted with the structural transition of the three-way junction, as in the complex structure. Our study provides insights into the viral RNA's sophisticated strategy for optimal docking to hijack the host protein.
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Affiliation(s)
- Shunsuke Imai
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama, 230-0045, Japan.
| | - Hiroshi Suzuki
- Cellular and Structural Physiology Laboratory (CeSPL), Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Yoshinori Fujiyoshi
- Cellular and Structural Physiology Laboratory (CeSPL), Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Ichio Shimada
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama, 230-0045, Japan.
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8528, Japan.
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10
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Kehlenbach RH, Neumann P, Ficner R, Dickmanns A. Interaction of nucleoporins with nuclear transport receptors: a structural perspective. Biol Chem 2023; 404:791-805. [PMID: 37210735 DOI: 10.1515/hsz-2023-0155] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 05/04/2023] [Indexed: 05/23/2023]
Abstract
Soluble nuclear transport receptors and stationary nucleoporins are at the heart of the nucleocytoplasmic transport machinery. A subset of nucleoporins contains characteristic and repetitive FG (phenylalanine-glycine) motifs, which are the basis for the permeability barrier of the nuclear pore complex (NPC) that controls transport of macromolecules between the nucleus and the cytoplasm. FG-motifs can interact with each other and/or with transport receptors, mediating their translocation across the NPC. The molecular details of homotypic and heterotypic FG-interactions have been analyzed at the structural level. In this review, we focus on the interactions of nucleoporins with nuclear transport receptors. Besides the conventional FG-motifs as interaction spots, a thorough structural analysis led us to identify additional similar motifs at the binding interface between nucleoporins and transport receptors. A detailed analysis of all known human nucleoporins revealed a large number of such phenylalanine-containing motifs that are not buried in the predicted 3D-structure of the respective protein but constitute part of the solvent-accessible surface area. Only nucleoporins that are rich in conventional FG-repeats are also enriched for these motifs. This additional layer of potential low-affinity binding sites on nucleoporins for transport receptors may have a strong impact on the interaction of transport complexes with the nuclear pore and, thus, the efficiency of nucleocytoplasmic transport.
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Affiliation(s)
- Ralph H Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany
| | - Piotr Neumann
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, GZMB, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, D-37077 Göttingen, Germany
| | - Ralf Ficner
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, GZMB, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, D-37077 Göttingen, Germany
| | - Achim Dickmanns
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, GZMB, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, D-37077 Göttingen, Germany
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11
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Shestakova ED, Smirnova VV, Shatsky IN, Terenin IM. Specific mechanisms of translation initiation in higher eukaryotes: the eIF4G2 story. RNA (NEW YORK, N.Y.) 2023; 29:282-299. [PMID: 36517212 PMCID: PMC9945437 DOI: 10.1261/rna.079462.122] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The eukaryotic initiation factor 4G2 (eIF4G2, DAP5, Nat1, p97) was discovered in 1997. Over the past two decades, dozens of papers have presented contradictory data on eIF4G2 function. Since its identification, eIF4G2 has been assumed to participate in noncanonical translation initiation mechanisms, but recent results indicate that it can be involved in scanning as well. In particular, eIF4G2 provides leaky scanning through some upstream open reading frames (uORFs), which are typical for long 5' UTRs of mRNAs from higher eukaryotes. It is likely the protein can also help the ribosome overcome other impediments during scanning of the 5' UTRs of animal mRNAs. This may explain the need for eIF4G2 in higher eukaryotes, as many mRNAs that encode regulatory proteins have rather long and highly structured 5' UTRs. Additionally, they often bind to various proteins, which also hamper the movement of scanning ribosomes. This review discusses the suggested mechanisms of eIF4G2 action, denotes obscure or inconsistent results, and proposes ways to uncover other fundamental mechanisms in which this important protein factor may be involved in higher eukaryotes.
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Affiliation(s)
- Ekaterina D Shestakova
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Victoria V Smirnova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Ivan N Shatsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Ilya M Terenin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia
- Sirius University of Science and Technology, Sochi 354349, Russia
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