1
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Nomburg J, Doherty EE, Price N, Bellieny-Rabelo D, Zhu YK, Doudna JA. Birth of protein folds and functions in the virome. Nature 2024:10.1038/s41586-024-07809-y. [PMID: 39187718 DOI: 10.1038/s41586-024-07809-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 07/10/2024] [Indexed: 08/28/2024]
Abstract
The rapid evolution of viruses generates proteins that are essential for infectivity and replication but with unknown functions, due to extreme sequence divergence1. Here, using a database of 67,715 newly predicted protein structures from 4,463 eukaryotic viral species, we found that 62% of viral proteins are structurally distinct and lack homologues in the AlphaFold database2,3. Among the remaining 38% of viral proteins, many have non-viral structural analogues that revealed surprising similarities between human pathogens and their eukaryotic hosts. Structural comparisons suggested putative functions for up to 25% of unannotated viral proteins, including those with roles in the evasion of innate immunity. In particular, RNA ligase T-like phosphodiesterases were found to resemble phage-encoded proteins that hydrolyse the host immune-activating cyclic dinucleotides 3',3'- and 2',3'-cyclic GMP-AMP (cGAMP). Experimental analysis showed that RNA ligase T homologues encoded by avian poxviruses similarly hydrolyse cGAMP, showing that RNA ligase T-mediated targeting of cGAMP is an evolutionarily conserved mechanism of immune evasion that is present in both bacteriophage and eukaryotic viruses. Together, the viral protein structural database and analyses presented here afford new opportunities to identify mechanisms of virus-host interactions that are common across the virome.
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Affiliation(s)
- Jason Nomburg
- Gladstone-UCSF Institute of Data Science and Biotechnology, San Francisco, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Erin E Doherty
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA
| | - Nathan Price
- Gladstone-UCSF Institute of Data Science and Biotechnology, San Francisco, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Daniel Bellieny-Rabelo
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA
| | - Yong K Zhu
- Gladstone-UCSF Institute of Data Science and Biotechnology, San Francisco, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Jennifer A Doudna
- Gladstone-UCSF Institute of Data Science and Biotechnology, San Francisco, CA, USA.
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA.
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA.
- Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA, USA.
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA.
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2
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Elder JJH, Papadopoulos R, Hayne CK, Stanley RE. The making and breaking of tRNAs by ribonucleases. Trends Genet 2024; 40:511-525. [PMID: 38641471 PMCID: PMC11152995 DOI: 10.1016/j.tig.2024.03.007] [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: 02/08/2024] [Revised: 03/21/2024] [Accepted: 03/21/2024] [Indexed: 04/21/2024]
Abstract
Ribonucleases (RNases) play important roles in supporting canonical and non-canonical roles of tRNAs by catalyzing the cleavage of the tRNA phosphodiester backbone. Here, we highlight how recent advances in cryo-electron microscopy (cryo-EM), protein structure prediction, reconstitution experiments, tRNA sequencing, and other studies have revealed new insight into the nucleases that process tRNA. This represents a very diverse group of nucleases that utilize distinct mechanisms to recognize and cleave tRNA during different stages of a tRNA's life cycle including biogenesis, fragmentation, surveillance, and decay. In this review, we provide a synthesis of the structure, mechanism, regulation, and modes of tRNA recognition by tRNA nucleases, along with open questions for future investigation.
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Affiliation(s)
- Jessica J H Elder
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Ry Papadopoulos
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA; Department of Chemistry, University of Chicago, Chicago, IL, USA
| | - Cassandra K Hayne
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA.
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA.
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3
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Xi J, Snieckute G, Martínez JF, Arendrup FSW, Asthana A, Gaughan C, Lund AH, Bekker-Jensen S, Silverman RH. Initiation of a ZAKα-dependent ribotoxic stress response by the innate immunity endoribonuclease RNase L. Cell Rep 2024; 43:113998. [PMID: 38551960 PMCID: PMC11090160 DOI: 10.1016/j.celrep.2024.113998] [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: 10/12/2023] [Revised: 02/13/2024] [Accepted: 03/08/2024] [Indexed: 04/09/2024] Open
Abstract
RNase L is an endoribonuclease of higher vertebrates that functions in antiviral innate immunity. Interferons induce oligoadenylate synthetase enzymes that sense double-stranded RNA of viral origin leading to the synthesis of 2',5'-oligoadenylate (2-5A) activators of RNase L. However, it is unknown precisely how RNase L remodels the host cell transcriptome. To isolate effects of RNase L from other effects of double-stranded RNA or virus, 2-5A is directly introduced into cells. Here, we report that RNase L activation by 2-5A causes a ribotoxic stress response involving the MAP kinase kinase kinase (MAP3K) ZAKα, MAP2Ks, and the stress-activated protein kinases JNK and p38α. RNase L activation profoundly alters the transcriptome by widespread depletion of mRNAs associated with different cellular functions but also by JNK/p38α-stimulated induction of inflammatory genes. These results show that the 2-5A/RNase L system triggers a protein kinase cascade leading to proinflammatory signaling and apoptosis.
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Affiliation(s)
- Jiajia Xi
- Department Cancer Biology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH 44195, USA.
| | - Goda Snieckute
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark; Center for Gene Expression, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - José Francisco Martínez
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark; Center for Gene Expression, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | | | - Abhishek Asthana
- Department Cancer Biology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH 44195, USA
| | - Christina Gaughan
- Department Cancer Biology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH 44195, USA
| | - Anders H Lund
- Biotech Research and Innovation Center, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark
| | - Simon Bekker-Jensen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark; Center for Gene Expression, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark.
| | - Robert H Silverman
- Department Cancer Biology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH 44195, USA.
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4
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Chen J, Chen H, Li S, Lin X, Hu R, Zhang K, Liu L. Structural and mechanistic insights into ribosomal ITS2 RNA processing by nuclease-kinase machinery. eLife 2024; 12:RP86847. [PMID: 38180340 PMCID: PMC10942766 DOI: 10.7554/elife.86847] [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: 01/06/2024] Open
Abstract
Precursor ribosomal RNA (pre-rRNA) processing is a key step in ribosome biosynthesis and involves numerous RNases. A HEPN (higher eukaryote and prokaryote nucleotide binding) nuclease Las1 and a polynucleotide kinase Grc3 assemble into a tetramerase responsible for rRNA maturation. Here, we report the structures of full-length Saccharomyces cerevisiae and Cyberlindnera jadinii Las1-Grc3 complexes, and C. jadinii Las1. The Las1-Grc3 structures show that the central coiled-coil domain of Las1 facilitates pre-rRNA binding and cleavage, while the Grc3 C-terminal loop motif directly binds to the HEPN active center of Las1 and regulates pre-rRNA cleavage. Structural comparison between Las1 and Las1-Grc3 complex exhibits that Grc3 binding induces conformational rearrangements of catalytic residues associated with HEPN nuclease activation. Biochemical assays identify that Las1 processes pre-rRNA at the two specific sites (C2 and C2'), which greatly facilitates rRNA maturation. Our structures and specific pre-rRNA cleavage findings provide crucial insights into the mechanism and pathway of pre-rRNA processing in ribosome biosynthesis.
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Affiliation(s)
- Jiyun Chen
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen UniversityXiamenChina
| | - Hong Chen
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen UniversityXiamenChina
| | - Shanshan Li
- MOE Key Laboratory for Cellular Dynamics and Division of Life Sciences and Medicine, University of Science and Technology of ChinaHefeiChina
| | - Xiaofeng Lin
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen UniversityXiamenChina
| | - Rong Hu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen UniversityXiamenChina
| | - Kaiming Zhang
- MOE Key Laboratory for Cellular Dynamics and Division of Life Sciences and Medicine, University of Science and Technology of ChinaHefeiChina
| | - Liang Liu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen UniversityXiamenChina
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5
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Borgelt L, Wu P. Targeting Ribonucleases with Small Molecules and Bifunctional Molecules. ACS Chem Biol 2023; 18:2101-2113. [PMID: 37382390 PMCID: PMC10594538 DOI: 10.1021/acschembio.3c00191] [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: 03/30/2023] [Accepted: 06/06/2023] [Indexed: 06/30/2023]
Abstract
Ribonucleases (RNases) cleave and process RNAs, thereby regulating the biogenesis, metabolism, and degradation of coding and noncoding RNAs. Thus, small molecules targeting RNases have the potential to perturb RNA biology, and RNases have been studied as therapeutic targets of antibiotics, antivirals, and agents for autoimmune diseases and cancers. Additionally, the recent advances in chemically induced proximity approaches have led to the discovery of bifunctional molecules that target RNases to achieve RNA degradation or inhibit RNA processing. Here, we summarize the efforts that have been made to discover small-molecule inhibitors and activators targeting bacterial, viral, and human RNases. We also highlight the emerging examples of RNase-targeting bifunctional molecules and discuss the trends in developing such molecules for both biological and therapeutic applications.
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Affiliation(s)
- Lydia Borgelt
- Chemical Genomics Centre, Max
Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, Dortmund 44227, Germany
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, Dortmund 44227, Germany
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6
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Xi J, Snieckute G, Asthana A, Gaughan C, Bekker-Jensen S, Silverman RH. Initiation of a ZAKα-dependent Ribotoxic Stress Response by the Innate Immunity Endoribonuclease RNase L. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.12.562082. [PMID: 37873202 PMCID: PMC10592832 DOI: 10.1101/2023.10.12.562082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
RNase L is a regulated endoribonuclease in higher vertebrates that functions in antiviral innate immunity. Interferons induce OAS enzymes that sense double-stranded RNA of viral origin leading to synthesis of 2',5'-oligoadenylate (2-5A) activators of RNase L. However, it is unknown precisely how RNase L inhibits viral infections. To isolate effects of RNase L from other effects of double-stranded RNA or virus, 2-5A was directly introduced into cells. Here we report that RNase L activation by 2-5A causes a ribotoxic stress response that requires the ribosome-associated MAP3K, ZAKα. Subsequently, the stress-activated protein kinases (SAPK) JNK and p38α are phosphorylated. RNase L activation profoundly altered the transcriptome by widespread depletion of mRNAs associated with different cellular functions, but also by SAPK-dependent induction of inflammatory genes. Our findings show that 2-5A is a ribotoxic stressor that causes RNA damage through RNase L triggering a ZAKα kinase cascade leading to proinflammatory signaling and apoptosis.
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Affiliation(s)
- Jiajia Xi
- Department Cancer Biology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH, 44195, USA
| | - Goda Snieckute
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
- Center for Gene Expression, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Abhishek Asthana
- Department Cancer Biology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH, 44195, USA
| | - Christina Gaughan
- Department Cancer Biology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH, 44195, USA
| | - Simon Bekker-Jensen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
- Center for Gene Expression, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Robert H Silverman
- Department Cancer Biology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH, 44195, USA
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7
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Chu L, Gong Z, Wang W, Han GZ. Origin of the OAS-RNase L innate immune pathway before the rise of jawed vertebrates via molecular tinkering. Proc Natl Acad Sci U S A 2023; 120:e2304687120. [PMID: 37487089 PMCID: PMC10400998 DOI: 10.1073/pnas.2304687120] [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: 03/22/2023] [Accepted: 06/26/2023] [Indexed: 07/26/2023] Open
Abstract
Discriminating self from nonself is fundamental to immunity. Yet, it remains largely elusive how the mechanisms of self and nonself discrimination originated. Sensing double-stranded RNA as nonself, the 2',5'-oligoadenylate synthetase (OAS)-ribonuclease L (RNase L) pathway represents a crucial component of innate immunity. Here, we combine phylogenomic and functional analyses to show that the functional OAS-RNase L pathway likely originated through tinkering with preexisting proteins before the rise of jawed vertebrates during or before the Silurian period (444 to 419 Mya). Multiple concerted losses of OAS and RNase L occurred during the evolution of jawed vertebrates, further supporting the ancient coupling between OAS and RNase L. Moreover, both OAS and RNase L genes evolved under episodic positive selection across jawed vertebrates, suggesting a long-running evolutionary arms race between the OAS-RNase L pathway and microbes. Our findings illuminate how an innate immune pathway originated via molecular tinkering.
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Affiliation(s)
- Lingyu Chu
- College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu210023, China
| | - Zhen Gong
- College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu210023, China
| | - Wenqiang Wang
- College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu210023, China
| | - Guan-Zhu Han
- College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu210023, China
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8
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Yao T, Foo C, Zheng G, Huang R, Li Q, Shen J, Wang Z. Insight into the mechanisms of coronaviruses evading host innate immunity. Biochim Biophys Acta Mol Basis Dis 2023; 1869:166671. [PMID: 36858323 PMCID: PMC9968664 DOI: 10.1016/j.bbadis.2023.166671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 09/15/2022] [Accepted: 02/10/2023] [Indexed: 03/03/2023]
Abstract
The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) induced coronavirus disease 2019 (COVID-19) has recently caused a pandemic. Patients with COVID-19 presented with a wide spectrum of symptoms for the disease, from entirely asymptomatic disease to full-blown pneumonia and multiorgan failures. More evidence emerged, showing the production of interferons (IFNs) in the severe cases were significantly lower than their milder counterparts, suggesting linkage of COVID-19 to impaired innate immunity. This review presents a brief overview of how coronaviruses evade innate immunity, according to the current studies about SARS-CoV and middle-east respiratory syndrome-coronavirus (MERS-CoV). The coronaviruses manage to block, escape, or dampen the innate immune response by antagonizing double-stranded RNA (dsRNA) sensor, mitochondrial antiviral-signaling protein (MAVS) and stimulator of IFN genes (STING) pathways, epigenetic modification, posttranslational modifications, and host mRNA translation. We provide novel insights into a comprehensive therapy to combat SARS-CoV-2 infection.
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Affiliation(s)
- Tengteng Yao
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200092, China; Department of Ophthalmology, Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai 200025, China
| | - Chingchoon Foo
- Family Medicine Programme College of Medicine & Veterinary Medicine, The University of Edinburgh, EH89YL Edinburgh, United Kingdom
| | - Guopei Zheng
- Department of Ophthalmology, Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai 200025, China
| | - Rui Huang
- Department of Ophthalmology, Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai 200025, China
| | - Qian Li
- Department of Ophthalmology, Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai 200025, China
| | - Jianfeng Shen
- Department of Ophthalmology, Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai 200025, China.
| | - Zhaoyang Wang
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200092, China.
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9
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Hwang J, Haacke N, Borgelt L, Qiu X, Gasper R, Wu P. Rational design and evaluation of 2-((pyrrol-2-yl)methylene)thiophen-4-ones as RNase L inhibitors. Eur J Med Chem 2023; 256:115439. [PMID: 37201427 DOI: 10.1016/j.ejmech.2023.115439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 04/13/2023] [Accepted: 04/30/2023] [Indexed: 05/20/2023]
Abstract
Ribonuclease L (RNase L) plays a crucial role in an antiviral pathway of interferon-induced innate immunity by degrading RNAs to prevent viral replication. Modulating RNase L activity thus mediates the innate immune responses and inflammation. Although a few small molecule-based RNase L modulators have been reported, only limited molecules have been mechanistically investigated. This study explored the strategy of RNase L targeting by using a structure-based rational design approach and evaluated the RNase L-binding and inhibitory activities of the yielded 2-((pyrrol-2-yl)methylene)thiophen-4-ones, which exhibited improved inhibitory effect as determined by in vitro FRET and gel-based RNA cleavage assay. A further structural optimization study yielded selected thiophenones that showed >30-fold more potent inhibitory activity than that of sunitinib, the approved kinase inhibitor with reported RNase L inhibitory activity. The binding mode with RNase L for the resulting thiophenones was analyzed by using docking analysis. Furthermore, the obtained 2-((pyrrol-2-yl)methylene)thiophen-4-ones exhibited efficient inhibition of RNA degradation in cellular rRNA cleavage assay. The newly designed thiophenones are the most potent synthetic RNase L inhibitors reported to date and the results revealed in our study lay the foundation for the development of future RNase L-modulating small molecules with new scaffold and improved potency.
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Affiliation(s)
- Jimin Hwang
- Chemical Genomics Centre, Max Planck Institute of Molecular Physiology, Dortmund, 44227, Germany; Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund, 44227, Germany; Faculty of Chemistry and Chemical Biology, TU Dortmund University, Dortmund, 44227, Germany
| | - Neele Haacke
- Chemical Genomics Centre, Max Planck Institute of Molecular Physiology, Dortmund, 44227, Germany; Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund, 44227, Germany; Faculty of Chemistry and Chemical Biology, TU Dortmund University, Dortmund, 44227, Germany
| | - Lydia Borgelt
- Chemical Genomics Centre, Max Planck Institute of Molecular Physiology, Dortmund, 44227, Germany; Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund, 44227, Germany; Faculty of Chemistry and Chemical Biology, TU Dortmund University, Dortmund, 44227, Germany
| | - Xiaqiu Qiu
- Chemical Genomics Centre, Max Planck Institute of Molecular Physiology, Dortmund, 44227, Germany; Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund, 44227, Germany; Faculty of Chemistry and Chemical Biology, TU Dortmund University, Dortmund, 44227, Germany
| | - Raphael Gasper
- Crystallography and Biophysics Unit, Max Planck Institute of Molecular Physiology, Dortmund, 44227, Germany
| | - Peng Wu
- Chemical Genomics Centre, Max Planck Institute of Molecular Physiology, Dortmund, 44227, Germany; Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund, 44227, Germany.
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10
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IFN-Induced PARPs—Sensors of Foreign Nucleic Acids? Pathogens 2023; 12:pathogens12030457. [PMID: 36986379 PMCID: PMC10057411 DOI: 10.3390/pathogens12030457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 03/10/2023] [Accepted: 03/12/2023] [Indexed: 03/17/2023] Open
Abstract
Cells have developed different strategies to cope with viral infections. Key to initiating a defense response against viruses is the ability to distinguish foreign molecules from their own. One central mechanism is the perception of foreign nucleic acids by host proteins which, in turn, initiate an efficient immune response. Nucleic acid sensing pattern recognition receptors have evolved, each targeting specific features to discriminate viral from host RNA. These are complemented by several RNA-binding proteins that assist in sensing of foreign RNAs. There is increasing evidence that the interferon-inducible ADP-ribosyltransferases (ARTs; PARP9—PARP15) contribute to immune defense and attenuation of viruses. However, their activation, subsequent targets, and precise mechanisms of interference with viruses and their propagation are still largely unknown. Best known for its antiviral activities and its role as RNA sensor is PARP13. In addition, PARP9 has been recently described as sensor for viral RNA. Here we will discuss recent findings suggesting that some PARPs function in antiviral innate immunity. We expand on these findings and integrate this information into a concept that outlines how the different PARPs might function as sensors of foreign RNA. We speculate about possible consequences of RNA binding with regard to the catalytic activities of PARPs, substrate specificity and signaling, which together result in antiviral activities.
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11
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Gokul A, Arumugam T, Ramsuran V. Genetic Ethnic Differences in Human 2'-5'-Oligoadenylate Synthetase and Disease Associations: A Systematic Review. Genes (Basel) 2023; 14:527. [PMID: 36833454 PMCID: PMC9956131 DOI: 10.3390/genes14020527] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/14/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023] Open
Abstract
Recently, several studies have highlighted a skewed prevalence of infectious diseases within the African continent. Furthermore, a growing number of studies have demonstrated unique genetic variants found within the African genome are one of the contributing factors to the disease severity of infectious diseases within Africa. Understanding the host genetic mechanisms that offer protection against infectious diseases provides an opportunity to develop unique therapeutic interventions. Over the past two decades, several studies have linked the 2'-5'-oligoadenylate synthetase (OAS) family with a range of infectious diseases. More recently, the OAS-1 gene has also been associated with disease severity caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which led to a global pandemic. The OAS family serves as an antiviral factor through the interaction with Ribonuclease-Latent (RNase-L). This review explores the genetic variants observed within the OAS genes and the associations with various viral infections and how previously reported ethnic-specific polymorphisms drive clinical significance. This review provides an overview of OAS genetic association studies with a particular focus on viral diseases affecting individuals of African descent.
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Affiliation(s)
- Anmol Gokul
- School of Laboratory Medicine and Medical Sciences, College of Health Science, University of KwaZulu-Natal, Durban 4041, South Africa
| | - Thilona Arumugam
- School of Laboratory Medicine and Medical Sciences, College of Health Science, University of KwaZulu-Natal, Durban 4041, South Africa
| | - Veron Ramsuran
- School of Laboratory Medicine and Medical Sciences, College of Health Science, University of KwaZulu-Natal, Durban 4041, South Africa
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban 4001, South Africa
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12
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Prangley E, Korennykh A. 2-5A-Mediated decay (2-5AMD): from antiviral defense to control of host RNA. Crit Rev Biochem Mol Biol 2022; 57:477-491. [PMID: 36939319 PMCID: PMC10576847 DOI: 10.1080/10409238.2023.2181308] [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: 02/28/2022] [Revised: 10/18/2022] [Accepted: 02/13/2023] [Indexed: 03/21/2023]
Abstract
Mammalian cells are exquisitely sensitive to the presence of double-stranded RNA (dsRNA), a molecule that they interpret as a signal of viral presence requiring immediate attention. Upon sensing dsRNA cells activate the innate immune response, which involves transcriptional mechanisms driving inflammation and secretion of interferons (IFNs) and interferon-stimulated genes (ISGs), as well as synthesis of RNA-like signaling molecules comprised of three or more 2'-5'-linked adenylates (2-5As). 2-5As were discovered some forty years ago and described as IFN-induced inhibitors of protein synthesis. The efforts of many laboratories, aimed at elucidating the molecular mechanism and function of these mysterious RNA-like signaling oligonucleotides, revealed that 2-5A is a specific ligand for the kinase-family endonuclease RNase L. RNase L decays single-stranded RNA (ssRNA) from viruses and mRNAs (as well as other RNAs) from hosts in a process we proposed to call 2-5A-mediated decay (2-5AMD). During recent years it has become increasingly recognized that 2-5AMD is more than a blunt tool of viral RNA destruction, but a pathway deeply integrated into sensing and regulation of endogenous RNAs. Here we present an overview of recently emerged roles of 2-5AMD in host RNA regulation.
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Affiliation(s)
- Eliza Prangley
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Alexei Korennykh
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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13
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Borgelt L, Haacke N, Lampe P, Qiu X, Gasper R, Schiller D, Hwang J, Sievers S, Wu P. Small-molecule screening of ribonuclease L binders for RNA degradation. Biomed Pharmacother 2022; 154:113589. [PMID: 36029542 DOI: 10.1016/j.biopha.2022.113589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/16/2022] [Accepted: 08/17/2022] [Indexed: 11/15/2022] Open
Abstract
Small molecules targeting the ubiquitous latent ribonuclease (RNase L), which has limited sequence specificity toward single-stranded RNA substrates, hold great potential to be developed as broad-spectrum antiviral drugs by modulating the RNase L-mediated innate immune responses. The recent development of proximity-inducing bifunctional molecules, as described in the strategy of ribonuclease targeting chimeras, demonstrated that small-molecule RNase L activators can function as the essential RNase L-recruiting component to design bifunctional molecules for targeted RNA degradation. However, only a single screening study on small-molecule RNase L activators with poor potency has been reported to date. Herein, we established a FRET assay and conducted a screening of 240,000 small molecules to identify new RNase L activators with improved potency. The extremely low hit rate of less than 0.03% demonstrated the challenging nature of RNase L activation by small molecules available from current screening collections. A few hit compounds induced enhanced thermal stability of RNase L upon binding, although validation assays did not lead to the identification of compounds with significantly improved RNase L activating potency. The sulfonamide compound 17 induced a thermal shift of ~ 0.9 °C upon binding to RNase L, induced significant apoptosis in cancer cells, and showed single-digit micromolar inhibitory activity against cancer cell proliferation. This study paves the way for future structural optimization for the development of small-molecule RNase L binders.
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Affiliation(s)
- Lydia Borgelt
- Chemical Genomics Centre, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany; Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany; Faculty of Chemistry and Chemical Biology, TU Dortmund University, Dortmund 44227, Germany
| | - Neele Haacke
- Chemical Genomics Centre, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany; Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany; Faculty of Chemistry and Chemical Biology, TU Dortmund University, Dortmund 44227, Germany
| | - Philipp Lampe
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany; Compound Management and Screening Center, Dortmund 44227, Germany
| | - Xiaqiu Qiu
- Chemical Genomics Centre, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany; Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany; Faculty of Chemistry and Chemical Biology, TU Dortmund University, Dortmund 44227, Germany
| | - Raphael Gasper
- Crystallography and Biophysics Unit, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany
| | - Damian Schiller
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Dortmund 44227, Germany
| | - Jimin Hwang
- Chemical Genomics Centre, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany; Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany; Faculty of Chemistry and Chemical Biology, TU Dortmund University, Dortmund 44227, Germany
| | - Sonja Sievers
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany; Compound Management and Screening Center, Dortmund 44227, Germany
| | - Peng Wu
- Chemical Genomics Centre, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany; Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany.
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14
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Di Giorgio E, Xodo LE. Endogenous Retroviruses (ERVs): Does RLR (RIG-I-Like Receptors)-MAVS Pathway Directly Control Senescence and Aging as a Consequence of ERV De-Repression? Front Immunol 2022; 13:917998. [PMID: 35757716 PMCID: PMC9218063 DOI: 10.3389/fimmu.2022.917998] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 05/18/2022] [Indexed: 11/13/2022] Open
Abstract
Bi-directional transcription of Human Endogenous Retroviruses (hERVs) is a common feature of autoimmunity, neurodegeneration and cancer. Higher rates of cancer incidence, neurodegeneration and autoimmunity but a lower prevalence of autoimmune diseases characterize elderly people. Although the re-expression of hERVs is commonly observed in different cellular models of senescence as a result of the loss of their epigenetic transcriptional silencing, the hERVs modulation during aging is more complex, with a peak of activation in the sixties and a decline in the nineties. What is clearly accepted, instead, is the impact of the re-activation of dormant hERV on the maintenance of stemness and tissue self-renewing properties. An innate cellular immunity system, based on the RLR-MAVS circuit, controls the degradation of dsRNAs arising from the transcription of hERV elements, similarly to what happens for the accumulation of cytoplasmic DNA leading to the activation of cGAS/STING pathway. While agonists and inhibitors of the cGAS-STING pathway are considered promising immunomodulatory molecules, the effect of the RLR-MAVS pathway on innate immunity is still largely based on correlations and not on causality. Here we review the most recent evidence regarding the activation of MDA5-RIG1-MAVS pathway as a result of hERV de-repression during aging, immunosenescence, cancer and autoimmunity. We will also deal with the epigenetic mechanisms controlling hERV repression and with the strategies that can be adopted to modulate hERV expression in a therapeutic perspective. Finally, we will discuss if the RLR-MAVS signalling pathway actively modulates physiological and pathological conditions or if it is passively activated by them.
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Affiliation(s)
- Eros Di Giorgio
- Laboratory of Biochemistry, Department of Medicine, University of Udine, Udine, Italy
| | - Luigi E Xodo
- Laboratory of Biochemistry, Department of Medicine, University of Udine, Udine, Italy
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15
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Hua L, Zhang Q, Zhu X, Wang R, You Q, Wang L. Beyond Proteolysis-Targeting Chimeric Molecules: Designing Heterobifunctional Molecules Based on Functional Effectors. J Med Chem 2022; 65:8091-8112. [PMID: 35686733 DOI: 10.1021/acs.jmedchem.2c00316] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In recent years, with the successful development of proteolysis-targeting chimeric molecules (PROTACs), the potential of heterobifunctional molecules to contribute to reenvisioning drug design, especially small-molecule drugs, has been increasingly recognized. Inspired by PROTACs, diverse heterobifunctional molecules have been reported to simultaneously bind two or more molecules and bring them into proximity to interaction, such as ribonuclease-recruiting, autophagy-recruiting, lysosome-recruiting, kinase-recruiting, phosphatase-recruiting, glycosyltransferase-recruiting, and acetyltransferase-recruiting chimeras. On the basis of the heterobifunctional principle, more opportunities for advancing drug design by linking potential effectors to a protein of interest (POI) have emerged. Herein, we introduce heterobifunctional molecules other than PROTACs, summarize the limitations of existing molecules, list the main challenges, and propose perspectives for future research directions, providing insight into alternative design strategies based on substrate-proximity-based targeting.
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Affiliation(s)
- Liwen Hua
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, P. R. China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, P. R.China
| | - Qiuyue Zhang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, P. R. China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, P. R.China
| | - Xinyue Zhu
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, P. R. China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, P. R.China
| | - Ruoning Wang
- College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, P. R. China
| | - Qidong You
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, P. R. China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, P. R.China
| | - Lei Wang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, P. R. China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, P. R.China
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16
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Synthesis and Evaluation of RNase L-binding 2-aminothiophenes as anticancer agents. Bioorg Med Chem 2022; 58:116653. [DOI: 10.1016/j.bmc.2022.116653] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 01/31/2022] [Accepted: 02/01/2022] [Indexed: 01/08/2023]
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17
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Tang J, Dong B, Liu M, Liu S, Niu X, Gaughan C, Asthana A, Zhou H, Xu Z, Zhang G, Silverman RH, Huang H. Identification of Small Molecule Inhibitors of RNase L by Fragment-Based Drug Discovery. J Med Chem 2022; 65:1445-1457. [PMID: 34841869 PMCID: PMC10620946 DOI: 10.1021/acs.jmedchem.1c01156] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The pseudokinase-endoribonuclease RNase L plays important roles in antiviral innate immunity and is also implicated in many other cellular activities. The inhibition of RNase L showed therapeutic potential for Aicardi-Goutières syndrome (AGS). Thus, RNase L is a promising drug target. In this study, using an enzyme assay and NMR screening, we discovered 13 inhibitory fragments against RNase L. Cocrystal structures of RNase L separately complexed with two different fragments were determined in which both fragments bound to the ATP-binding pocket of the pseudokinase domain. Myricetin, vitexin, and hyperoside, three natural products sharing similar scaffolds with the fragment AC40357, demonstrated a potent inhibitory activity in vitro. In addition, myricetin has a promising cellular inhibitory activity. A cocrystal structure of RNase L with myricetin provided a structural basis for inhibitor design by allosterically modulating the ribonuclease activity. Our findings demonstrate that fragment screening can lead to the discovery of natural product inhibitors of RNase L.
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Affiliation(s)
- Jinle Tang
- State Key Laboratory of Chemical Oncogenomics, Laboratory of Structural Biology and Drug Discovery, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Beihua Dong
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Ming Liu
- State Key Laboratory of Chemical Oncogenomics, Laboratory of Structural Biology and Drug Discovery, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Shuyan Liu
- National Clinical Research Center for Infectious Diseases, Shenzhen Third People’s Hospital, Southern University of Science and Technology, Shenzhen 518112, China
| | - Xiaogang Niu
- College of Chemistry and Molecular Engineering, Beijing Nuclear Magnetic Resonance Center, Peking University, Beijing 100871, China
| | - Christina Gaughan
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Abhishek Asthana
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Huan Zhou
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
| | - Zhengshuang Xu
- State Key Laboratory of Chemical Oncogenomics, Laboratory of Structural Biology and Drug Discovery, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Guoliang Zhang
- National Clinical Research Center for Infectious Diseases, Shenzhen Third People’s Hospital, Southern University of Science and Technology, Shenzhen 518112, China
| | - Robert H. Silverman
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Hao Huang
- State Key Laboratory of Chemical Oncogenomics, Laboratory of Structural Biology and Drug Discovery, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
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18
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Schwartz SL, Dey D, Tanquary J, Bair CR, Lowen AC, Conn GL. Role of helical structure and dynamics in oligoadenylate synthetase 1 (OAS1) mismatch tolerance and activation by short dsRNAs. Proc Natl Acad Sci U S A 2022; 119:e2107111119. [PMID: 35017296 PMCID: PMC8784149 DOI: 10.1073/pnas.2107111119] [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: 05/23/2021] [Accepted: 11/17/2021] [Indexed: 11/18/2022] Open
Abstract
The 2'-5'-oligoadenylate synthetases (OAS) are innate immune sensors of cytosolic double-stranded RNA (dsRNA) that play a critical role in limiting viral infection. How these proteins are able to avoid aberrant activation by cellular RNAs is not fully understood, but adenosine-to-inosine (A-to-I) editing has been proposed to limit accumulation of endogenous RNAs that might otherwise cause stimulation of the OAS/RNase L pathway. Here, we aim to uncover whether and how such sequence modifications can restrict the ability of short, defined dsRNAs to activate the single-domain form of OAS, OAS1. Unexpectedly, we find that all tested inosine-containing dsRNAs have an increased capacity to activate OAS1, whether in a destabilizing (I•U) or standard Watson-Crick-like base pairing (I-C) context. Additional variants with strongly destabilizing A•C mismatches or stabilizing G-C pairs also exhibit increased capacity to activate OAS1, eliminating helical stability as a factor in the relative ability of the dsRNAs to activate OAS1. Using thermal difference spectra and molecular dynamics simulations, we identify both increased helical dynamics and specific local changes in helical structure as important factors in the capacity of short dsRNAs to activate OAS1. These helical features may facilitate more ready adoption of the distorted OAS1-bound conformation or stabilize important structures to predispose the dsRNA for optimal binding and activation of OAS1. These studies thus reveal the molecular basis for the greater capacity of some short dsRNAs to activate OAS1 in a sequence-independent manner.
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Affiliation(s)
- Samantha L Schwartz
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
- Graduate Program in Biochemistry, Cell and Developmental Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA 30322
| | - Debayan Dey
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
| | - Julia Tanquary
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
- Graduate Program in Biochemistry, Cell and Developmental Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA 30322
| | - Camden R Bair
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322
| | - Anice C Lowen
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322
| | - Graeme L Conn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322;
- Graduate Program in Biochemistry, Cell and Developmental Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA 30322
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19
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Yapasert R, Khaw-on P, Banjerdpongchai R. Coronavirus Infection-Associated Cell Death Signaling and Potential Therapeutic Targets. Molecules 2021; 26:7459. [PMID: 34946543 PMCID: PMC8706825 DOI: 10.3390/molecules26247459] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/29/2021] [Accepted: 12/06/2021] [Indexed: 12/12/2022] Open
Abstract
COVID-19 is the name of the disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection that occurred in 2019. The virus-host-specific interactions, molecular targets on host cell deaths, and the involved signaling are crucial issues, which become potential targets for treatment. Spike protein, angiotensin-converting enzyme 2 (ACE2), cathepsin L-cysteine peptidase, transmembrane protease serine 2 (TMPRSS2), nonstructural protein 1 (Nsp1), open reading frame 7a (ORF7a), viral main protease (3C-like protease (3CLpro) or Mpro), RNA dependent RNA polymerase (RdRp) (Nsp12), non-structural protein 13 (Nsp13) helicase, and papain-like proteinase (PLpro) are molecules associated with SARS-CoV infection and propagation. SARS-CoV-2 can induce host cell death via five kinds of regulated cell death, i.e., apoptosis, necroptosis, pyroptosis, autophagy, and PANoptosis. The mechanisms of these cell deaths are well established and can be disrupted by synthetic small molecules or natural products. There are a variety of compounds proven to play roles in the cell death inhibition, such as pan-caspase inhibitor (z-VAD-fmk) for apoptosis, necrostatin-1 for necroptosis, MCC950, a potent and specific inhibitor of the NLRP3 inflammasome in pyroptosis, and chloroquine/hydroxychloroquine, which can mitigate the corresponding cell death pathways. However, NF-κB signaling is another critical anti-apoptotic or survival route mediated by SARS-CoV-2. Such signaling promotes viral survival, proliferation, and inflammation by inducing the expression of apoptosis inhibitors such as Bcl-2 and XIAP, as well as cytokines, e.g., TNF. As a result, tiny natural compounds functioning as proteasome inhibitors such as celastrol and curcumin can be used to modify NF-κB signaling, providing a responsible method for treating SARS-CoV-2-infected patients. The natural constituents that aid in inhibiting viral infection, progression, and amplification of coronaviruses are also emphasized, which are in the groups of alkaloids, flavonoids, terpenoids, diarylheptanoids, and anthraquinones. Natural constituents derived from medicinal herbs have anti-inflammatory and antiviral properties, as well as inhibitory effects, on the viral life cycle, including viral entry, replication, assembly, and release of COVID-19 virions. The phytochemicals contain a high potential for COVID-19 treatment. As a result, SARS-CoV-2-infected cell death processes and signaling might be of high efficacy for therapeutic targeting effects and yielding encouraging outcomes.
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Affiliation(s)
- Rittibet Yapasert
- Department of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand;
| | - Patompong Khaw-on
- Faculty of Nursing, Chiang Mai University, Chiang Mai 50200, Thailand;
| | - Ratana Banjerdpongchai
- Department of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand;
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20
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Karasik A, Jones GD, DePass AV, Guydosh NR. Activation of the antiviral factor RNase L triggers translation of non-coding mRNA sequences. Nucleic Acids Res 2021; 49:6007-6026. [PMID: 33556964 DOI: 10.1093/nar/gkab036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 01/06/2021] [Accepted: 02/03/2021] [Indexed: 11/15/2022] Open
Abstract
Ribonuclease L (RNase L) is activated as part of the innate immune response and plays an important role in the clearance of viral infections. When activated, it endonucleolytically cleaves both viral and host RNAs, leading to a global reduction in protein synthesis. However, it remains unknown how widespread RNA decay, and consequent changes in the translatome, promote the elimination of viruses. To study how this altered transcriptome is translated, we assayed the global distribution of ribosomes in RNase L activated human cells with ribosome profiling. We found that RNase L activation leads to a substantial increase in the fraction of translating ribosomes in ORFs internal to coding sequences (iORFs) and ORFs within 5' and 3' UTRs (uORFs and dORFs). Translation of these alternative ORFs was dependent on RNase L's cleavage activity, suggesting that mRNA decay fragments are translated to produce short peptides that may be important for antiviral activity.
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Affiliation(s)
- Agnes Karasik
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.,Postdoctoral Research Associate Training Program, National Institute of General Medical Sciences, National Institutes of Health, Bethesda, MD 20892, USA
| | - Grant D Jones
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Andrew V DePass
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nicholas R Guydosh
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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21
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Inhibition of Antiviral Innate Immunity by Foot-and-Mouth Disease Virus L pro through Interaction with the N-Terminal Domain of Swine RNase L. J Virol 2021; 95:e0036121. [PMID: 33980594 DOI: 10.1128/jvi.00361-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Foot-and-mouth disease virus (FMDV) is the pathogen of foot-and-mouth disease (FMD), which is a highly contagious disease in cloven-hoofed animals. To survive in the host, FMDV has evolved multiple strategies to antagonize host innate immune responses. In this study, we showed that the leader protease (Lpro) of FMDV, a papain-like proteinase, promoted viral replication by evading the antiviral interferon response through counteracting the 2',5'-oligoadenylate synthetase (OAS)/RNase L system. Specifically, we observed that the titers of Lpro deletion virus were significantly lower than those of wild-type FMDV (FMDV-WT) in cultured cells. Our mechanistic studies demonstrated that Lpro interfered with the OAS/RNase L pathway by interacting with the N-terminal domain of swine RNase L (sRNase L). Remarkably, Lpro of FMDV exhibited species-specific binding to RNase L in that the interaction was observed only in swine cells, not human, monkey, or canine cells. Lastly, we presented evidence that by interacting with sRNase L, FMDV Lpro inhibited cellular apoptosis. Taken together, these results demonstrate a novel mechanism that Lpro utilizes to escape the OAS/RNase L-mediated antiviral defense pathway. IMPORTANCE FMDV is a picornavirus that causes a significant disease in agricultural animals. FMDV has developed diverse strategies to escape the host interferon response. Here, we show that Lpro of FMDV antagonizes the OAS/RNase L pathway, an important interferon effector pathway, by interacting with the N-terminal domain of sRNase L. Interestingly, such a virus-host interaction is species-specific because the interaction is detected only in swine cells, not in human, monkey, or canine cells. Furthermore, Lpro inhibits apoptosis through interacting with sRNase L. This study demonstrates a novel mechanism by which FMDV has evolved to inhibit host innate immune responses.
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22
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Kholodenko BN, Rauch N, Kolch W, Rukhlenko OS. A systematic analysis of signaling reactivation and drug resistance. Cell Rep 2021; 35:109157. [PMID: 34038718 PMCID: PMC8202068 DOI: 10.1016/j.celrep.2021.109157] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 02/24/2021] [Accepted: 04/29/2021] [Indexed: 01/07/2023] Open
Abstract
Increasing evidence suggests that the reactivation of initially inhibited signaling pathways causes drug resistance. Here, we analyze how network topologies affect signaling responses to drug treatment. Network-dependent drug resistance is commonly attributed to negative and positive feedback loops. However, feedback loops by themselves cannot completely reactivate steady-state signaling. Newly synthesized negative feedback regulators can induce a transient overshoot but cannot fully restore output signaling. Complete signaling reactivation can only occur when at least two routes, an activating and inhibitory, connect an inhibited upstream protein to a downstream output. Irrespective of the network topology, drug-induced overexpression or increase in target dimerization can restore or even paradoxically increase downstream pathway activity. Kinase dimerization cooperates with inhibitor-mediated alleviation of negative feedback. Our findings inform drug development by considering network context and optimizing the design drug combinations. As an example, we predict and experimentally confirm specific combinations of RAF inhibitors that block mutant NRAS signaling. Kholodenko et al. uncover signaling network circuitries and molecular mechanisms necessary and sufficient for complete reactivation or overshoot of steady-state signaling after kinase inhibitor treatment. The two means to revive signaling output fully are through network topology or reactivation of the kinase activity of the primary drug target. Blocking RAF dimer activity by a combination of type I½ and type II RAF inhibitors efficiently blocks mutant NRAS-driven ERK signaling.
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Affiliation(s)
- Boris N Kholodenko
- Systems Biology Ireland, School of Medicine and Medical Science, University College Dublin, Dublin, Ireland; Conway Institute of Biomolecular & Biomedical Research, University College Dublin, Dublin, Ireland; Department of Pharmacology, Yale University School of Medicine, New Haven, CT, USA.
| | - Nora Rauch
- Systems Biology Ireland, School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Walter Kolch
- Systems Biology Ireland, School of Medicine and Medical Science, University College Dublin, Dublin, Ireland; Conway Institute of Biomolecular & Biomedical Research, University College Dublin, Dublin, Ireland
| | - Oleksii S Rukhlenko
- Systems Biology Ireland, School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
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23
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Li W, Crotty K, Garrido Ruiz D, Voorhies M, Rivera C, Sil A, Mullins RD, Jacobson MP, Peschek J, Walter P. Protomer alignment modulates specificity of RNA substrate recognition by Ire1. eLife 2021; 10:e67425. [PMID: 33904404 PMCID: PMC8104961 DOI: 10.7554/elife.67425] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 04/27/2021] [Indexed: 11/21/2022] Open
Abstract
The unfolded protein response (UPR) maintains protein folding homeostasis in the endoplasmic reticulum (ER). In metazoan cells, the Ire1 branch of the UPR initiates two functional outputs-non-conventional mRNA splicing and selective mRNA decay (RIDD). By contrast, Ire1 orthologs from Saccharomyces cerevisiae and Schizosaccharomyces pombe are specialized for only splicing or RIDD, respectively. Previously, we showed that the functional specialization lies in Ire1's RNase activity, which is either stringently splice-site specific or promiscuous (Li et al., 2018). Here, we developed an assay that reports on Ire1's RNase promiscuity. We found that conversion of two amino acids within the RNase domain of S. cerevisiae Ire1 to their S. pombe counterparts rendered it promiscuous. Using biochemical assays and computational modeling, we show that the mutations rewired a pair of salt bridges at Ire1 RNase domain's dimer interface, changing its protomer alignment. Thus, Ire1 protomer alignment affects its substrates specificity.
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Affiliation(s)
- Weihan Li
- Department of Biochemistry and Biophysics, University of California San FranciscoSan FranciscoUnited States
- Howard Hughes Medical InstituteSan FranciscoUnited States
| | - Kelly Crotty
- Department of Biochemistry and Biophysics, University of California San FranciscoSan FranciscoUnited States
- Howard Hughes Medical InstituteSan FranciscoUnited States
| | - Diego Garrido Ruiz
- Department of Pharmaceutical Chemistry, University of California at San FranciscoSan FranciscoUnited States
| | - Mark Voorhies
- Department of Microbiology and Immunology, University of California at San FranciscoSan FranciscoUnited States
| | - Carlos Rivera
- Department of Molecular Biophysics and Biochemistry, Yale School of MedicineNew HavenUnited States
| | - Anita Sil
- Department of Microbiology and Immunology, University of California at San FranciscoSan FranciscoUnited States
| | - R Dyche Mullins
- Howard Hughes Medical InstituteSan FranciscoUnited States
- Department of Cellular and Molecular Pharmacology, University of California at San FranciscoSan FranciscoUnited States
| | - Matthew P Jacobson
- Department of Pharmaceutical Chemistry, University of California at San FranciscoSan FranciscoUnited States
| | - Jirka Peschek
- Department of Biochemistry and Biophysics, University of California San FranciscoSan FranciscoUnited States
- Howard Hughes Medical InstituteSan FranciscoUnited States
| | - Peter Walter
- Department of Biochemistry and Biophysics, University of California San FranciscoSan FranciscoUnited States
- Howard Hughes Medical InstituteSan FranciscoUnited States
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24
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Sunitinib inhibits RNase L by destabilizing its active dimer conformation. Biochem J 2021; 477:3387-3399. [PMID: 32830849 DOI: 10.1042/bcj20200260] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 07/27/2020] [Accepted: 08/24/2020] [Indexed: 02/06/2023]
Abstract
The pseudokinase (PK) RNase L is a functional ribonuclease and plays important roles in human innate immunity. The ribonuclease activity of RNase L can be regulated by the kinase inhibitor sunitinib. The combined use of oncolytic virus and sunitinib has been shown to exert synergistic effects in anticancer therapy. In this study, we aimed to uncover the mechanism of action through which sunitinib inhibits RNase L. We solved the crystal structures of RNase L in complex with sunitinib and its analogs toceranib and SU11652. Our results showed that sunitinib bound to the ATP-binding pocket of RNase L. Unexpectedly, the αA helix linking the ankyrin repeat-domain and the PK domain affected the binding mode of sunitinib and resulted in an unusual flipped orientation relative to other structures in PDB. Molecular dynamics simulations and dynamic light scattering results support that the binding of sunitinib in the PK domain destabilized the dimer conformation of RNase L and allosterically inhibited its ribonuclease activity. Our study suggested that dimer destabilization could be an effective strategy for the discovery of RNase L inhibitors and that targeting the ATP-binding pocket in the PK domain of RNase L was an efficient approach for modulating its ribonuclease activity.
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Ramnani B, Manivannan P, Jaggernauth S, Malathi K. ABCE1 Regulates RNase L-Induced Autophagy during Viral Infections. Viruses 2021; 13:v13020315. [PMID: 33670646 PMCID: PMC7922175 DOI: 10.3390/v13020315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/14/2021] [Accepted: 02/16/2021] [Indexed: 12/15/2022] Open
Abstract
Host response to a viral infection includes the production of type I interferon (IFN) and the induction of interferon-stimulated genes that have broad antiviral effects. One of the key antiviral effectors is the IFN-inducible oligoadenylate synthetase/ribonuclease L (OAS/RNase L) pathway, which is activated by double-stranded RNA to synthesize unique oligoadenylates, 2-5A, to activate RNase L. RNase L exerts an antiviral effect by cleaving diverse RNA substrates, limiting viral replication; many viruses have evolved mechanisms to counteract the OAS/RNase L pathway. Here, we show that the ATP-binding cassette E1 (ABCE1) transporter, identified as an inhibitor of RNase L, regulates RNase L activity and RNase L-induced autophagy during viral infections. ABCE1 knockdown cells show increased RNase L activity when activated by 2-5A. Compared to parental cells, the autophagy-inducing activity of RNase L in ABCE1-depleted cells is enhanced with early onset. RNase L activation in ABCE1-depleted cells inhibits cellular proliferation and sensitizes cells to apoptosis. Increased activity of caspase-3 causes premature cleavage of autophagy protein, Beclin-1, promoting a switch from autophagy to apoptosis. ABCE1 regulates autophagy during EMCV infection, and enhanced autophagy in ABCE1 knockdown cells promotes EMCV replication. We identify ABCE1 as a host protein that inhibits the OAS/RNase L pathway by regulating RNase L activity, potentially affecting antiviral effects.
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Pillon MC, Gordon J, Frazier MN, Stanley RE. HEPN RNases - an emerging class of functionally distinct RNA processing and degradation enzymes. Crit Rev Biochem Mol Biol 2021; 56:88-108. [PMID: 33349060 PMCID: PMC7856873 DOI: 10.1080/10409238.2020.1856769] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/06/2020] [Accepted: 11/24/2020] [Indexed: 10/22/2022]
Abstract
HEPN (Higher Eukaryotes and Prokaryotes Nucleotide-binding) RNases are an emerging class of functionally diverse RNA processing and degradation enzymes. Members are defined by a small α-helical bundle encompassing a short consensus RNase motif. HEPN dimerization is a universal requirement for RNase activation as the conserved RNase motifs are precisely positioned at the dimer interface to form a composite catalytic center. While the core HEPN fold is conserved, the organization surrounding the HEPN dimer can support large structural deviations that contribute to their specialized functions. HEPN RNases are conserved throughout evolution and include bacterial HEPN RNases such as CRISPR-Cas and toxin-antitoxin associated nucleases, as well as eukaryotic HEPN RNases that adopt large multi-component machines. Here we summarize the canonical elements of the growing HEPN RNase family and identify molecular features that influence RNase function and regulation. We explore similarities and differences between members of the HEPN RNase family and describe the current mechanisms for HEPN RNase activation and inhibition.
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Affiliation(s)
- Monica C. Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Jacob Gordon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Meredith N. Frazier
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E. Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
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Mace PD, Murphy JM. There's more to death than life: Noncatalytic functions in kinase and pseudokinase signaling. J Biol Chem 2021; 296:100705. [PMID: 33895136 PMCID: PMC8141879 DOI: 10.1016/j.jbc.2021.100705] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 12/11/2022] Open
Abstract
Protein kinases are present in all domains of life and play diverse roles in cellular signaling. Whereas the impact of substrate phosphorylation by protein kinases has long been appreciated, it is becoming increasingly clear that protein kinases also play other, noncatalytic, functions. Here, we review recent developments in understanding the noncatalytic functions of protein kinases. Many noncatalytic activities are best exemplified by protein kinases that are devoid of enzymatic activity altogether-known as pseudokinases. These dead proteins illustrate that, beyond conventional notions of kinase function, catalytic activity can be dispensable for biological function. Through key examples we illustrate diverse mechanisms of noncatalytic kinase activity: as allosteric modulators; protein-based switches; scaffolds for complex assembly; and as competitive inhibitors in signaling pathways. In common, these noncatalytic mechanisms exploit the nature of the protein kinase fold as a versatile protein-protein interaction module. Many examples are also intrinsically linked to the ability of the protein kinase to switch between multiple states, a function shared with catalytic protein kinases. Finally, we consider the contemporary landscape of small molecules to modulate noncatalytic functions of protein kinases, which, although challenging, has significant potential given the scope of noncatalytic protein kinase function in health and disease.
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Affiliation(s)
- Peter D Mace
- Biochemistry Department, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
| | - James M Murphy
- Inflammation Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia.
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28
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A phenolic small molecule inhibitor of RNase L prevents cell death from ADAR1 deficiency. Proc Natl Acad Sci U S A 2020; 117:24802-24812. [PMID: 32958664 PMCID: PMC7547215 DOI: 10.1073/pnas.2006883117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The OAS–RNase L system is an innate immunity pathway activated by viral infection. Viral dsRNA stimulates OAS enzymes to produce short 2′,5′-oligoadenylates (2-5A) that activate RNase L, resulting in cleavage of single-stranded (ss) RNA. We discovered a small-molecule inhibitor of RNase L that rescues the toxic phenotype of cells deficient in the dsRNA-editing enzyme ADAR1. ADAR1 destabilizes dsRNA to prevent OAS activity. ADAR1 mutations are responsible for a subset of cases of Aicardi-Goutières syndrome (AGS), a severe neurodevelopmental and inflammatory genetic disease of children with no effective medical therapy. We posit that an RNase L inhibitor may have utility against cases of AGS in which RNase L is activated and other indications where overactivation of RNase L is harmful. The oligoadenylate synthetase (OAS)–RNase L system is an IFN-inducible antiviral pathway activated by viral infection. Viral double-stranded (ds) RNA activates OAS isoforms that synthesize the second messenger 2-5A, which binds and activates the pseudokinase-endoribonuclease RNase L. In cells, OAS activation is tamped down by ADAR1, an adenosine deaminase that destabilizes dsRNA. Mutation of ADAR1 is one cause of Aicardi-Goutières syndrome (AGS), an interferonopathy in children. ADAR1 deficiency in human cells can lead to RNase L activation and subsequent cell death. To evaluate RNase L as a possible therapeutic target for AGS, we sought to identify small-molecule inhibitors of RNase L. A 500-compound library of protein kinase inhibitors was screened for modulators of RNase L activity in vitro. We identified ellagic acid (EA) as a hit with 10-fold higher selectivity against RNase L compared with its nearest paralog, IRE1. SAR analysis identified valoneic acid dilactone (VAL) as a superior inhibitor of RNase L, with 100-fold selectivity over IRE1. Mechanism-of-action analysis indicated that EA and VAL do not bind to the pseudokinase domain of RNase L despite acting as ATP competitive inhibitors of the protein kinase CK2. VAL is nontoxic and functional in cells, although with a 1,000-fold decrease in potency, as measured by RNA cleavage activity in response to treatment with dsRNA activator or by rescue of cell lethality resulting from self dsRNA induced by ADAR1 deficiency. These studies lay the foundation for understanding novel modes of regulating RNase L function using small-molecule inhibitors and avenues of therapeutic potential.
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29
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Weiße J, Rosemann J, Krauspe V, Kappler M, Eckert AW, Haemmerle M, Gutschner T. RNA-Binding Proteins as Regulators of Migration, Invasion and Metastasis in Oral Squamous Cell Carcinoma. Int J Mol Sci 2020; 21:E6835. [PMID: 32957697 PMCID: PMC7555251 DOI: 10.3390/ijms21186835] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/14/2020] [Accepted: 09/17/2020] [Indexed: 02/06/2023] Open
Abstract
Nearly 7.5% of all human protein-coding genes have been assigned to the class of RNA-binding proteins (RBPs), and over the past decade, RBPs have been increasingly recognized as important regulators of molecular and cellular homeostasis. RBPs regulate the post-transcriptional processing of their target RNAs, i.e., alternative splicing, polyadenylation, stability and turnover, localization, or translation as well as editing and chemical modification, thereby tuning gene expression programs of diverse cellular processes such as cell survival and malignant spread. Importantly, metastases are the major cause of cancer-associated deaths in general, and particularly in oral cancers, which account for 2% of the global cancer mortality. However, the roles and architecture of RBPs and RBP-controlled expression networks during the diverse steps of the metastatic cascade are only incompletely understood. In this review, we will offer a brief overview about RBPs and their general contribution to post-transcriptional regulation of gene expression. Subsequently, we will highlight selected examples of RBPs that have been shown to play a role in oral cancer cell migration, invasion, and metastasis. Last but not least, we will present targeting strategies that have been developed to interfere with the function of some of these RBPs.
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Affiliation(s)
- Jonas Weiße
- Junior Research Group ‘RNA Biology and Pathogenesis’, Medical Faculty, Martin-Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany; (J.W.); (J.R.); (V.K.)
| | - Julia Rosemann
- Junior Research Group ‘RNA Biology and Pathogenesis’, Medical Faculty, Martin-Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany; (J.W.); (J.R.); (V.K.)
| | - Vanessa Krauspe
- Junior Research Group ‘RNA Biology and Pathogenesis’, Medical Faculty, Martin-Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany; (J.W.); (J.R.); (V.K.)
| | - Matthias Kappler
- Department of Oral and Maxillofacial Plastic Surgery, Medical Faculty, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany;
| | - Alexander W. Eckert
- Department of Cranio Maxillofacial Surgery, Paracelsus Medical University, 90471 Nuremberg, Germany;
| | - Monika Haemmerle
- Institute of Pathology, Section for Experimental Pathology, Medical Faculty, Martin-Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany;
| | - Tony Gutschner
- Junior Research Group ‘RNA Biology and Pathogenesis’, Medical Faculty, Martin-Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany; (J.W.); (J.R.); (V.K.)
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30
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Schwartz SL, Park EN, Vachon VK, Danzy S, Lowen AC, Conn GL. Human OAS1 activation is highly dependent on both RNA sequence and context of activating RNA motifs. Nucleic Acids Res 2020; 48:7520-7531. [PMID: 32678884 PMCID: PMC7367156 DOI: 10.1093/nar/gkaa513] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 06/01/2020] [Accepted: 06/04/2020] [Indexed: 12/18/2022] Open
Abstract
2′-5′-Oligoadenylate synthetases (OAS) are innate immune sensors of cytosolic double-stranded RNA (dsRNA) and play a critical role in limiting viral infection. dsRNA binding induces allosteric structural changes in OAS1 that reorganize its catalytic center to promote synthesis of 2′-5′-oligoadenylate and thus activation of endoribonuclease L. Specific RNA sequences and structural motifs can also enhance activation of OAS1 through currently undefined mechanisms. To better understand these drivers of OAS activation, we tested the impact of defined sequence changes within a short dsRNA that strongly activates OAS1. Both in vitro and in human A549 cells, appending a 3′-end single-stranded pyrimidine (3′-ssPy) can strongly enhance OAS1 activation or have no effect depending on its location, suggesting that other dsRNA features are necessary for correct presentation of the motif to OAS1. Consistent with this idea, we also find that the dsRNA binding position is dictated by an established consensus sequence (WWN9WG). Unexpectedly, however, not all sequences fitting this consensus activate OAS1 equivalently, with strong dependence on the identity of both partially conserved (W) and non-conserved (N9) residues. A picture thus emerges in which both specific RNA features and the context in which they are presented dictate the ability of short dsRNAs to activate OAS1.
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Affiliation(s)
- Samantha L Schwartz
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road NE, Atlanta, GA 30322, USA.,Graduate Program in Biochemistry, Cell and Developmental Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, USA
| | - Esther N Park
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Virginia K Vachon
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road NE, Atlanta, GA 30322, USA.,Graduate Program in Microbiology and Molecular Genetics, Graduate Division of Biological and Biomedical Sciences, Emory University, USA
| | - Shamika Danzy
- Department of Microbiology and Immunology, Emory University School of Medicine, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Anice C Lowen
- Graduate Program in Microbiology and Molecular Genetics, Graduate Division of Biological and Biomedical Sciences, Emory University, USA.,Department of Microbiology and Immunology, Emory University School of Medicine, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Graeme L Conn
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road NE, Atlanta, GA 30322, USA.,Graduate Program in Biochemistry, Cell and Developmental Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, USA.,Graduate Program in Microbiology and Molecular Genetics, Graduate Division of Biological and Biomedical Sciences, Emory University, USA
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31
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Abstract
Protein-RNA interactions have crucial roles in various cellular activities, which, when dysregulated, can lead to a range of human diseases. The identification of small molecules that target the interaction between RNA-binding proteins (RBPs) and RNA is progressing rapidly and represents a novel strategy for the discovery of chemical probes that facilitate understanding of the cellular functions of RBPs and of therapeutic agents with new mechanisms of action. In this Review, I present a current overview of targeting emerging RBPs using small-molecule inhibitors and recent progress in this burgeoning field. Small-molecule inhibitors that were reported for three representative emerging classes of RBPs, the microRNA-binding protein LIN28, the single-stranded or double-stranded RNA-binding Toll-like receptors and the CRISPR-associated (Cas) proteins, are highlighted from a medicinal-chemistry and chemical-biology perspective. However, although this field is burgeoning, challenges remain in the discovery and characterization of small-molecule inhibitors of RBPs.
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32
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Chen B, Tian EK, He B, Tian L, Han R, Wang S, Xiang Q, Zhang S, El Arnaout T, Cheng W. Overview of lethal human coronaviruses. Signal Transduct Target Ther 2020; 5:89. [PMID: 32533062 PMCID: PMC7289715 DOI: 10.1038/s41392-020-0190-2] [Citation(s) in RCA: 190] [Impact Index Per Article: 47.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 02/05/2023] Open
Abstract
Coronavirus infections of multiple origins have spread to date worldwide, causing severe respiratory diseases. Seven coronaviruses that infect humans have been identified: HCoV-229E, HCoV-OC43, HCoV-NL63, HCoV-HKU1, SARS-CoV, MERS-CoV, and SARS-CoV-2. Among them, SARS-CoV and MERS-CoV caused outbreaks in 2002 and 2012, respectively. SARS-CoV-2 (COVID-19) is the most recently discovered. It has created a severe worldwide outbreak beginning in late 2019, leading to date to over 4 million cases globally. Viruses are genetically simple, yet highly diverse. However, the recent outbreaks of SARS-CoV and MERS-CoV, and the ongoing outbreak of SARS-CoV-2, indicate that there remains a long way to go to identify and develop specific therapeutic treatments. Only after gaining a better understanding of their pathogenic mechanisms can we minimize viral pandemics. This paper mainly focuses on SARS-CoV, MERS-CoV, and SARS-CoV-2. Here, recent studies are summarized and reviewed, with a focus on virus-host interactions, vaccine-based and drug-targeted therapies, and the development of new approaches for clinical diagnosis and treatment.
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Affiliation(s)
- Bin Chen
- Division of Respiratory and Critical Care Medicine, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Er-Kang Tian
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China
| | - Bin He
- Department of Emergency Medicine, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Lejin Tian
- Division of Respiratory and Critical Care Medicine, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Ruiying Han
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China
| | - Shuangwen Wang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China
| | - Qianrong Xiang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China
| | - Shu Zhang
- Department of Emergency Medicine, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | | | - Wei Cheng
- Division of Respiratory and Critical Care Medicine, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China.
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33
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Differential effects of 'resurrecting' Csp pseudoproteases during Clostridioides difficile spore germination. Biochem J 2020; 477:1459-1478. [PMID: 32242623 PMCID: PMC7200643 DOI: 10.1042/bcj20190875] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 03/31/2020] [Accepted: 04/03/2020] [Indexed: 01/02/2023]
Abstract
Clostridioides difficile is a spore-forming bacterial pathogen that is the leading cause of hospital-acquired gastroenteritis. C. difficile infections begin when its spore form germinates in the gut upon sensing bile acids. These germinants induce a proteolytic signaling cascade controlled by three members of the subtilisin-like serine protease family, CspA, CspB, and CspC. Notably, even though CspC and CspA are both pseudoproteases, they are nevertheless required to sense germinants and activate the protease, CspB. Thus, CspC and CspA are part of a growing list of pseudoenzymes that play important roles in regulating cellular processes. However, despite their importance, the structural properties of pseudoenzymes that allow them to function as regulators remain poorly understood. Our recently solved crystal structure of CspC revealed that its pseudoactive site residues align closely with the catalytic triad of CspB, suggesting that it might be possible to ‘resurrect' the ancestral protease activity of the CspC and CspA pseudoproteases. Here, we demonstrate that restoring the catalytic triad to these pseudoproteases fails to resurrect their protease activity. We further show that the pseudoactive site substitutions differentially affect the stability and function of the CspC and CspA pseudoproteases: the substitutions destabilized CspC and impaired spore germination without affecting CspA stability or function. Thus, our results surprisingly reveal that the presence of a catalytic triad does not necessarily predict protease activity. Since homologs of C. difficile CspA occasionally carry an intact catalytic triad, our results indicate that bioinformatic predictions of enzyme activity may underestimate pseudoenzymes in rare cases.
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34
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Ghetti M, Vannini I, Storlazzi CT, Martinelli G, Simonetti G. Linear and circular PVT1 in hematological malignancies and immune response: two faces of the same coin. Mol Cancer 2020; 19:69. [PMID: 32228602 PMCID: PMC7104523 DOI: 10.1186/s12943-020-01187-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 03/18/2020] [Indexed: 12/19/2022] Open
Abstract
Non coding RNAs (ncRNAs) have emerged as regulators of human carcinogenesis by affecting the expression of key tumor suppressor genes and oncogenes. They are divided into short and long ncRNAs, according to their length. Circular RNAs (circRNAs) are included in the second group and were recently discovered as being originated by back-splicing, joining either single or multiple exons, or exons with retained introns. The human Plasmacytoma Variant Translocation 1 (PVT1) gene maps on the long arm of chromosome 8 (8q24) and encodes for 52 ncRNAs variants, including 26 linear and 26 circular isoforms, and 6 microRNAs. PVT1 genomic locus is 54 Kb downstream to MYC and several interactions have been described among these two genes, including a feedback regulatory mechanism. MYC-independent functions of PVT1/circPVT1 have been also reported, especially in the regulation of immune responses. We here review and discuss the role of both PVT1 and circPVT1 in the hematopoietic system. No information is currently available concerning their transforming ability in hematopoietic cells. However, present literature supports their cooperation with a more aggressive and/or undifferentiated cell phenotype, thus contributing to cancer progression. PVT1/circPVT1 upregulation through genomic amplification or rearrangements and/or increased transcription, provides a proliferative advantage to malignant cells in acute myeloid leukemia, acute promyelocytic leukemia, Burkitt lymphoma, multiple myeloma (linear PVT1) and acute lymphoblastic leukemia (circPVT1). In addition, PVT1 and circPVT1 regulate immune responses: the overexpression of the linear form in myeloid derived suppressor cells induced immune tolerance in preclinical tumor models and circPVT1 showed immunosuppressive properties in myeloid and lymphoid cell subsets. Overall, these recent data on PVT1 and circPVT1 functions in hematological malignancies and immune responses reflect two faces of the same coin: involvement in cancer progression by promoting a more aggressive phenotype of malignant cells and negative regulation of the immune system as a novel potential therapy-resistance mechanism.
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Affiliation(s)
- Martina Ghetti
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
| | - Ivan Vannini
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy.
| | | | - Giovanni Martinelli
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
| | - Giorgia Simonetti
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
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35
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Garcia-Doval C, Schwede F, Berk C, Rostøl JT, Niewoehner O, Tejero O, Hall J, Marraffini LA, Jinek M. Activation and self-inactivation mechanisms of the cyclic oligoadenylate-dependent CRISPR ribonuclease Csm6. Nat Commun 2020; 11:1596. [PMID: 32221291 PMCID: PMC7101355 DOI: 10.1038/s41467-020-15334-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 02/28/2020] [Indexed: 12/26/2022] Open
Abstract
Bacterial and archaeal CRISPR-Cas systems provide RNA-guided immunity against genetic invaders such as bacteriophages and plasmids. Upon target RNA recognition, type III CRISPR-Cas systems produce cyclic-oligoadenylate second messengers that activate downstream effectors, including Csm6 ribonucleases, via their CARF domains. Here, we show that Enteroccocus italicus Csm6 (EiCsm6) degrades its cognate cyclic hexa-AMP (cA6) activator, and report the crystal structure of EiCsm6 bound to a cA6 mimic. Our structural, biochemical, and in vivo functional assays reveal how cA6 recognition by the CARF domain activates the Csm6 HEPN domains for collateral RNA degradation, and how CARF domain-mediated cA6 cleavage provides an intrinsic off-switch to limit Csm6 activity in the absence of ring nucleases. These mechanisms facilitate rapid invader clearance and ensure termination of CRISPR interference to limit self-toxicity. Upon target RNA recognition, type III CRISPR-Cas systems produce cyclic oligoadenylates that activate effectors such as Csm6 ribonucleases. Here, Garcia-Doval et al. show that Enteroccocus italicus Csm6 degrades its cyclic hexa-AMP activator, and report the crystal structure of the protein bound to an activator mimic.
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Affiliation(s)
- Carmela Garcia-Doval
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Frank Schwede
- Biolog Life Science Institute GmbH & Co. KG, Flughafendamm 9a, D-28199, Bremen, Germany
| | - Christian Berk
- Department of Chemistry and Applied Biosciences, Institute for Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, CH-8093, Zurich, Switzerland
| | - Jakob T Rostøl
- Laboratory of Bacteriology, The Rockefeller University, 1230 York Avenue, New York, NY, 10065-6399, USA
| | - Ole Niewoehner
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Oliver Tejero
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Jonathan Hall
- Department of Chemistry and Applied Biosciences, Institute for Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, CH-8093, Zurich, Switzerland
| | - Luciano A Marraffini
- Laboratory of Bacteriology, The Rockefeller University, 1230 York Avenue, New York, NY, 10065-6399, USA.,Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Martin Jinek
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.
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36
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Pillon MC, Goslen KH, Gordon J, Wells ML, Williams JG, Stanley RE. It takes two (Las1 HEPN endoribonuclease domains) to cut RNA correctly. J Biol Chem 2020; 295:5857-5870. [PMID: 32220933 DOI: 10.1074/jbc.ra119.011193] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 03/23/2020] [Indexed: 12/26/2022] Open
Abstract
The ribosome biogenesis factor Las1 is an essential endoribonuclease that is well-conserved across eukaryotes and a newly established member of the higher eukaryotes and prokaryotes nucleotide-binding (HEPN) domain-containing nuclease family. HEPN nucleases participate in diverse RNA cleavage pathways and share a short HEPN nuclease motif (RφXXXH) important for RNA cleavage. Most HEPN nucleases participate in stress-activated RNA cleavage pathways; Las1 plays a fundamental role in processing pre-rRNA. Underscoring the significance of Las1 function in the cell, mutations in the human LAS1L (LAS1-like) gene have been associated with neurological dysfunction. Two juxtaposed HEPN nuclease motifs create Las1's composite nuclease active site, but the roles of the individual HEPN motif residues are poorly defined. Here using a combination of in vivo experiments in Saccharomyces cerevisiae and in vitro assays, we show that both HEPN nuclease motifs are required for Las1 nuclease activity and fidelity. Through in-depth sequence analysis and systematic mutagenesis, we determined the consensus HEPN motif in the Las1 subfamily and uncovered its canonical and specialized elements. Using reconstituted Las1 HEPN-HEPN' chimeras, we defined the molecular requirements for RNA cleavage. Intriguingly, both copies of the Las1 HEPN motif were important for nuclease function, revealing that both HEPN motifs participate in coordinating the RNA within the Las1 active site. We also established that conformational flexibility of the two HEPN domains is important for proper nuclease function. The results of our work reveal critical information about how dual HEPN domains come together to drive Las1-mediated RNA cleavage.
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Affiliation(s)
- Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709
| | - Kevin H Goslen
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709
| | - Jacob Gordon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709
| | - Melissa L Wells
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709
| | - Jason G Williams
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709.
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37
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Yao RW, Liu CX, Chen LL. Linking RNA Processing and Function. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2020; 84:67-82. [PMID: 32019863 DOI: 10.1101/sqb.2019.84.039495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
RNA processing is critical for eukaryotic mRNA maturation and function. It appears there is no exception for other types of RNAs. Long noncoding RNAs (lncRNAs) represent a subclass of noncoding RNAs, have sizes of >200 nucleotides (nt), and participate in various aspects of gene regulation. Although many lncRNAs are capped, polyadenylated, and spliced just like mRNAs, others are derived from primary transcripts of RNA polymerase II and stabilized by forming circular structures or by ending with small nucleolar RNA-protein complexes. Here we summarize the recent progress in linking the processing and function of these unconventionally processed lncRNAs; we also discuss how directional RNA movement is achieved using the radial flux movement of nascent precursor ribosomal RNA (pre-rRNA) in the human nucleolus as an example.
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Affiliation(s)
- Run-Wen Yao
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Chu-Xiao Liu
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Ling-Ling Chen
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
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38
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Abstract
Pseudokinases are members of the protein kinase superfamily but signal primarily through noncatalytic mechanisms. Many pseudokinases contribute to the pathologies of human diseases, yet they remain largely unexplored as drug targets owing to challenges associated with modulation of their biological functions. Our understanding of the structure and physiological roles of pseudokinases has improved substantially over the past decade, revealing intriguing similarities between pseudokinases and their catalytically active counterparts. Pseudokinases often adopt conformations that are analogous to those seen in catalytically active kinases and, in some cases, can also bind metal cations and/or nucleotides. Several clinically approved kinase inhibitors have been shown to influence the noncatalytic functions of active kinases, providing hope that similar properties in pseudokinases could be pharmacologically regulated. In this Review, we discuss known roles of pseudokinases in disease, their unique structural features and the progress that has been made towards developing pseudokinase-directed therapeutics.
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39
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Mino T, Iwai N, Endo M, Inoue K, Akaki K, Hia F, Uehata T, Emura T, Hidaka K, Suzuki Y, Standley DM, Okada-Hatakeyama M, Ohno S, Sugiyama H, Yamashita A, Takeuchi O. Translation-dependent unwinding of stem-loops by UPF1 licenses Regnase-1 to degrade inflammatory mRNAs. Nucleic Acids Res 2019; 47:8838-8859. [PMID: 31329944 PMCID: PMC7145602 DOI: 10.1093/nar/gkz628] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/05/2019] [Accepted: 07/12/2019] [Indexed: 01/14/2023] Open
Abstract
Regnase-1-mediated mRNA decay (RMD), in which inflammatory mRNAs harboring specific stem–loop structures are degraded, is a critical part of proper immune homeostasis. Prior to initial translation, Regnase-1 associates with target stem–loops but does not carry out endoribonucleolytic cleavage. Single molecule imaging revealed that UPF1 is required to first unwind the stem–loops, thus licensing Regnase-1 to proceed with RNA degradation. Following translation, Regnase-1 physically associates with UPF1 using two distinct points of interaction: The Regnase-1 RNase domain binds to SMG1-phosphorylated residue T28 in UPF1; in addition, an intrinsically disordered segment in Regnase-1 binds to the UPF1 RecA domain, enhancing the helicase activity of UPF1. The SMG1-UPF1–Regnase-1 axis targets pioneer rounds of translation and is critical for rapid resolution of inflammation through restriction of the number of proteins translated by a given mRNA. Furthermore, small-molecule inhibition of SMG1 prevents RNA unwinding in dendritic cells, allowing post-transcriptional control of innate immune responses.
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Affiliation(s)
- Takashi Mino
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Noriki Iwai
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Masayuki Endo
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan.,Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Yoshida-ushinomiyacho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kentaro Inoue
- Department of Computer Science and Systems Engineering, Faculty of Engineering, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Kotaro Akaki
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Fabian Hia
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Takuya Uehata
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Tomoko Emura
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kumi Hidaka
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Yutaka Suzuki
- Laboratory of Functional Genomics, Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8562, Japan
| | - Daron M Standley
- Department of Genome Informatics, Genome Information Research Center, Research Institute for Microbial Diseases (RIMD), Osaka University, Osaka 565-0871, Japan
| | - Mariko Okada-Hatakeyama
- Laboratory for Integrated Cellular Systems, RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan.,Laboratory of Cell Systems, Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Shigeo Ohno
- Department of Molecular Biology, Yokohama City University School of Medicine, Kanagawa 236-0004, Japan
| | - Hiroshi Sugiyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan.,Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Yoshida-ushinomiyacho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Akio Yamashita
- Department of Molecular Biology, Yokohama City University School of Medicine, Kanagawa 236-0004, Japan
| | - Osamu Takeuchi
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
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40
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Activation of RNase L in Egyptian Rousette Bat-Derived RoNi/7 Cells Is Dependent Primarily on OAS3 and Independent of MAVS Signaling. mBio 2019; 10:mBio.02414-19. [PMID: 31719180 PMCID: PMC6851283 DOI: 10.1128/mbio.02414-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Many RNA viruses that are highly pathogenic in humans are relatively apathogenic in their bat reservoirs, making it important to compare innate immune responses in bats to those well characterized in humans. One such antiviral response is the OAS-RNase L pathway. OASs, upon sensing dsRNA, produce 2-5A, leading to activation of RNase L which degrades viral and host RNA, limiting viral replication. Analysis of Egyptian Rousette bat sequences revealed three OAS genes expressing OAS1, OAS2, and OAS3 proteins. Interferon treatment or viral infection induces all three bat OAS mRNAs. In these bat cells as in human cells, RNase L activation and its antiviral activity are dependent primarily on OAS3 while MAVS signaling is not required. Importantly, our findings indicate the OAS-RNase L system is a primary response to virus rather than a secondary effect of interferon signaling and therefore can be activated early in infection or while interferon signaling is antagonized. Bats are reservoirs for many RNA viruses that are highly pathogenic in humans yet relatively apathogenic in the natural host. It has been suggested that differences in innate immunity are responsible. The antiviral OAS-RNase L pathway is well characterized in humans, but there is little known about its activation and antiviral activity in bats. During infection, OASs, upon sensing double-stranded RNA (dsRNA), produce 2′-5′ oligoadenylates (2-5A), leading to activation of RNase L which degrades viral and host RNA, limiting viral replication. Humans encode three active OASs (OAS1 to -3). Analysis of the Egyptian Rousette bat genome combined with mRNA sequencing from bat RoNi/7 cells revealed three homologous OAS proteins. Interferon alpha treatment or viral infection induced all three OAS mRNAs, but RNase L mRNA is constitutively expressed. Sindbis virus (SINV) or vaccinia virus (VACVΔE3L) infection of wild-type (WT) or OAS1-KO (knockout), OAS2-KO, or MAVS-KO RoNi/7 cells, but not RNase L-KO or OAS3-KO cells, induces robust RNase L activation. SINV replication is 100- to 200-fold higher in the absence of RNase L or OAS3 than in WT cells. However, MAVS-KO had no detectable effect on RNA degradation or replication. Thus, in RoNi/7 bat cells, as in human cells, activation of RNase L during infection and its antiviral activity are dependent primarily on OAS3 while MAVS signaling is not required for the activation of RNase L and restriction of infection. Our findings indicate that OAS proteins serve as pattern recognition receptors (PRRs) to recognize viral dsRNA and that this pathway is a primary response to virus rather than a secondary effect of interferon signaling.
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41
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Rath S, Prangley E, Donovan J, Demarest K, Wingreen NS, Meir Y, Korennykh A. Concerted 2-5A-Mediated mRNA Decay and Transcription Reprogram Protein Synthesis in the dsRNA Response. Mol Cell 2019; 75:1218-1228.e6. [PMID: 31494033 DOI: 10.1016/j.molcel.2019.07.027] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 06/13/2019] [Accepted: 07/16/2019] [Indexed: 01/09/2023]
Abstract
Viral and endogenous double-stranded RNA (dsRNA) is a potent trigger for programmed RNA degradation by the 2-5A/RNase L complex in cells of all mammals. This 2-5A-mediated decay (2-5AMD) is a conserved stress response switching global protein synthesis from homeostasis to production of interferons (IFNs). To understand this mechanism, we examined 2-5AMD in human cells and found that it triggers polysome collapse characteristic of inhibited translation initiation. We determined that translation initiation complexes and ribosomes purified from translation-arrested cells remain functional. However, spike-in RNA sequencing (RNA-seq) revealed cell-wide decay of basal mRNAs accompanied by rapid accumulation of mRNAs encoding innate immune proteins. Our data attribute this 2-5AMD evasion to better stability of defense mRNAs and positive feedback in the IFN response amplified by RNase L-resistant molecules. We conclude that 2-5AMD and transcription act in concert to refill mammalian cells with defense mRNAs, thereby "prioritizing" the synthesis of innate immune proteins.
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Affiliation(s)
- Sneha Rath
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Eliza Prangley
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Jesse Donovan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Kaitlin Demarest
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Ned S Wingreen
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Yigal Meir
- Department of Physics, Ben Gurion University, Beer-Sheva 84105, Israel
| | - Alexei Korennykh
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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42
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Pillon MC, Hsu AL, Krahn JM, Williams JG, Goslen KH, Sobhany M, Borgnia MJ, Stanley RE. Cryo-EM reveals active site coordination within a multienzyme pre-rRNA processing complex. Nat Struct Mol Biol 2019; 26:830-839. [PMID: 31488907 PMCID: PMC6733591 DOI: 10.1038/s41594-019-0289-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 07/30/2019] [Indexed: 12/22/2022]
Abstract
Ribosome assembly is a complex process reliant on the coordination of trans-acting enzymes to produce functional ribosomal subunits and secure the translational capacity of cells. The endoribonuclease (RNase) Las1 and the polynucleotide kinase (PNK) Grc3 assemble into a multienzyme complex, herein designated RNase PNK, to orchestrate processing of precursor ribosomal RNA (rRNA). RNase PNK belongs to the functionally diverse HEPN nuclease superfamily, whose members rely on distinct cues for nuclease activation. To establish how RNase PNK coordinates its dual enzymatic activities, we solved a series of cryo-EM structures of Chaetomium thermophilum RNase PNK in multiple conformational states. The structures reveal that RNase PNK adopts a butterfly-like architecture, harboring a composite HEPN nuclease active site flanked by discrete RNA kinase sites. We identify two molecular switches that coordinate nuclease and kinase function. Together, our structures and corresponding functional studies establish a new mechanism of HEPN nuclease activation essential for ribosome production.
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Affiliation(s)
- Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Allen L Hsu
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Jason G Williams
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Kevin H Goslen
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Mack Sobhany
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Mario J Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA.
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43
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Gordon J, Pillon MC, Stanley RE. Nol9 Is a Spatial Regulator for the Human ITS2 Pre-rRNA Endonuclease-Kinase Complex. J Mol Biol 2019; 431:3771-3786. [PMID: 31288032 DOI: 10.1016/j.jmb.2019.07.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/28/2019] [Accepted: 07/01/2019] [Indexed: 12/01/2022]
Abstract
The ribosome plays a universal role in translating the cellular proteome. Defects in the ribosome assembly factor Las1L are associated with congenital lethal motor neuron disease and X-linked intellectual disability disorders, yet its role in processing precursor ribosomal RNA (pre-rRNA) is largely unclear. The Las1L endoribonuclease associates with the Nol9 polynucleotide kinase to form the internal transcribed spacer 2 (ITS2) pre-rRNA endonuclease-kinase machinery. Together, Las1L-Nol9 catalyzes RNA cleavage and phosphorylation to mark the ITS2 for degradation. While ITS2 processing is critical for the production of functional ribosomes, the regulation of mammalian Las1L-Nol9 remains obscure. Here we characterize the human Las1L-Nol9 complex and identify critical molecular features that regulate its assembly and spatial organization. We establish that Las1L and Nol9 form a higher-order complex and identify the regions responsible for orchestrating this intricate architecture. Structural analysis by high-resolution imaging defines the intricate spatial pattern of Las1L-Nol9 within the nucleolar sub-structure linked with late pre-rRNA processing events. Furthermore, we uncover a Nol9-encoded nucleolar localization sequence that is responsible for nucleolar transport of the assembled Las1L-Nol9 complex. Together, these data provide a mechanism for the assembly and nucleolar localization of the human ITS2 pre-rRNA endonuclease-kinase complex.
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Affiliation(s)
- Jacob Gordon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA.
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44
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Oroz J, Laurents DV. RNA binding proteins: Diversity from microsurgeons to cowboys. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194398. [PMID: 31271896 DOI: 10.1016/j.bbagrm.2019.06.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 06/03/2019] [Accepted: 06/13/2019] [Indexed: 01/21/2023]
Abstract
The conformation and mechanism of proteins that degrade and bind RNA, which has provided key insights into post-transcriptional gene regulation, is explored here. During the twentieth century's last decades, the characterization of ribonucleases and RNA binding domains revealed the diversity of their reaction mechanisms and modes of RNA recognition, and the bases of protein folding, substrate specificity and binding affinity. More recent research showed how these domains combine through oligomerization or genetic recombination to create larger proteins with highly specific and readily programmable ribonucleolytic activity. In the last 15 years, the study of the capacity of proteins, usually disordered, to pool RNAs into discrete, non-aqueous microdroplets to facilitate their transport, modification and degradation - analogous to cowboys herding cattle - has advanced our comprehension of gene expression. Finally, the current uses of RNA binding proteins and the future applications of protein/RNA microdroplets are highlighted.
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Affiliation(s)
- Javier Oroz
- "Rocasolano" Institute of Physical Chemistry, Spanish National Research Council, Serrano 119, Madrid 28006, Spain
| | - Douglas V Laurents
- "Rocasolano" Institute of Physical Chemistry, Spanish National Research Council, Serrano 119, Madrid 28006, Spain.
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45
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Mayo CB, Erlandsen H, Mouser DJ, Feinstein AG, Robinson VL, May ER, Cole JL. Structural Basis of Protein Kinase R Autophosphorylation. Biochemistry 2019; 58:2967-2977. [PMID: 31246429 DOI: 10.1021/acs.biochem.9b00161] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The RNA-activated protein kinase, PKR, is a key mediator of the innate immunity response to viral infection. Viral double-stranded RNAs induce PKR dimerization and autophosphorylation. The PKR kinase domain forms a back-to-back dimer. However, intermolecular ( trans) autophosphorylation is not feasible in this arrangement. We have obtained PKR kinase structures that resolves this dilemma. The kinase protomers interact via the known back-to-back interface as well as a front-to-front interface that is formed by exchange of activation segments. Mutational analysis of the front-to-front interface support a functional role in PKR activation. Molecular dynamics simulations reveal that the activation segment is highly dynamic in the front-to-front dimer and can adopt conformations conducive to phosphoryl transfer. We propose a mechanism where back-to-back dimerization induces a conformational change that activates PKR to phosphorylate a "substrate" kinase docked in a front-to-front geometry. This mechanism may be relevant to related kinases that phosphorylate the eukaryotic initiation factor eIF2α.
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46
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Ceccarelli DF, Ivantsiv S, Mullin AA, Coyaud E, Manczyk N, Maisonneuve P, Kurinov I, Zhao L, Go C, Gingras AC, Raught B, Cordes S, Sicheri F. FAM105A/OTULINL Is a Pseudodeubiquitinase of the OTU-Class that Localizes to the ER Membrane. Structure 2019; 27:1000-1012.e6. [PMID: 31056421 DOI: 10.1016/j.str.2019.03.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 02/23/2019] [Accepted: 03/27/2019] [Indexed: 12/16/2022]
Abstract
Pseudoenzymes have been identified across a diverse range of enzyme classes and fulfill important cellular functions. Examples of pseudoenzymes exist within ubiquitin conjugating and deubiquitinase (DUB) protein families. Here we characterize FAM105A/OTULINL, the only putative pseudodeubiquitinase of the ovarian tumor protease (OTU domain) family in humans. The crystal structure of FAM105A revealed that the OTU domain possesses structural deficiencies in both active site and substrate-binding infrastructure predicted to impair normal DUB function. We confirmed the absence of catalytic function against all ubiquitin linkages and an inability of FAM105A to bind ubiquitin compared with catalytically active FAM105B/OTULIN. FAM105A co-localized with KDEL markers and Lamin B1 at the endoplasmic reticulum (ER) and nuclear envelope, respectively. Accordingly, the FAM105A interactome exhibited significant enrichment in proteins localized to the ER/outer nuclear, Golgi and vesicular membranes. In light of undetectable deubiquitinase activity, we posit that FAM105A/OTULINL functions through its ability to mediate protein-protein interactions.
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Affiliation(s)
- Derek F Ceccarelli
- Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Sofiia Ivantsiv
- Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Amber Anne Mullin
- Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Etienne Coyaud
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Noah Manczyk
- Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Pierre Maisonneuve
- Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Igor Kurinov
- Department of Chemistry and Chemical Biology, Cornell University, NE-CAT, Argonne, IL 60439, USA
| | - Liang Zhao
- Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Chris Go
- Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Anne-Claude Gingras
- Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Brian Raught
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada.
| | - Sabine Cordes
- Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.
| | - Frank Sicheri
- Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada.
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47
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Structure and Degradation of Circular RNAs Regulate PKR Activation in Innate Immunity. Cell 2019; 177:865-880.e21. [DOI: 10.1016/j.cell.2019.03.046] [Citation(s) in RCA: 365] [Impact Index Per Article: 73.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 01/29/2019] [Accepted: 03/25/2019] [Indexed: 11/19/2022]
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48
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Schwartz SL, Conn GL. RNA regulation of the antiviral protein 2'-5'-oligoadenylate synthetase. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1534. [PMID: 30989826 DOI: 10.1002/wrna.1534] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/12/2019] [Accepted: 03/14/2019] [Indexed: 12/25/2022]
Abstract
The innate immune system is a broad collection of critical intra- and extra-cellular processes that limit the infectivity of diverse pathogens. The 2'-5'-oligoadenylate synthetase (OAS) family of enzymes are important sensors of cytosolic double-stranded RNA (dsRNA) that play a critical role in limiting viral infection by activating the latent ribonuclease (RNase L) to halt viral replication and establish an antiviral state. Attesting to the importance of the OAS/RNase L pathway, diverse viruses have developed numerous distinct strategies to evade the effects of OAS activation. How OAS proteins are regulated by viral or cellular RNAs is not fully understood but several recent studies have provided important new insights into the molecular mechanisms of OAS activation by dsRNA. Other studies have revealed unanticipated features of RNA sequence and structure that strongly enhance activation of at least one OAS family member. While these discoveries represent important advances, they also underscore the fact that much remains to be learned about RNA-mediated regulation of the OAS/RNase L pathway. In particular, defining the full complement of RNA molecular signatures that activate OAS is essential to our understanding of how these proteins maximize their protective role against pathogens while still accurately discriminating host molecules to avoid inadvertent activation by cellular RNAs. A more complete knowledge of OAS regulation may also serve as a foundation for the development of novel antiviral therapeutic strategies and lead the way to a deeper understanding of currently unappreciated cellular functions of the OAS/RNase L pathway in the absence of infection. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Translation > Translation Regulation.
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Affiliation(s)
- Samantha L Schwartz
- Department of Biochemistry, Emory University School of Medicine and Graduate Program in Biochemistry, Cell and Developmental Biology (BCDB), Atlanta, Georgia
| | - Graeme L Conn
- Department of Biochemistry, Emory University School of Medicine and Graduate Program in Biochemistry, Cell and Developmental Biology (BCDB), Atlanta, Georgia
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Beraki T, Hu X, Broncel M, Young JC, O'Shaughnessy WJ, Borek D, Treeck M, Reese ML. Divergent kinase regulates membrane ultrastructure of the Toxoplasma parasitophorous vacuole. Proc Natl Acad Sci U S A 2019; 116:6361-6370. [PMID: 30850550 PMCID: PMC6442604 DOI: 10.1073/pnas.1816161116] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Apicomplexan parasites replicate within a protective organelle, called the parasitophorous vacuole (PV). The Toxoplasma gondii PV is filled with a network of tubulated membranes, which are thought to facilitate trafficking of effectors and nutrients. Despite being critical to parasite virulence, there is scant mechanistic understanding of the network's functions. Here, we identify the parasite-secreted kinase WNG1 (With-No-Gly-loop) as a critical regulator of tubular membrane biogenesis. WNG1 family members adopt an atypical protein kinase fold lacking the glycine rich ATP-binding loop that is required for catalysis in canonical kinases. Unexpectedly, we find that WNG1 is an active protein kinase that localizes to the PV lumen and phosphorylates PV-resident proteins, several of which are essential for the formation of a functional intravacuolar network. Moreover, we show that WNG1-dependent phosphorylation of these proteins is required for their membrane association, and thus their ability to tubulate membranes. Consequently, WNG1 knockout parasites have an aberrant PV membrane ultrastructure. Collectively, our results describe a unique family of Toxoplasma kinases and implicate phosphorylation of secreted proteins as a mechanism of regulating PV development during parasite infection.
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Affiliation(s)
- Tsebaot Beraki
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, TX 75390
| | - Xiaoyu Hu
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, TX 75390
| | - Malgorzata Broncel
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, NW1 1AT London United Kingdom
| | - Joanna C Young
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, NW1 1AT London United Kingdom
| | - William J O'Shaughnessy
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, TX 75390
| | - Dominika Borek
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Moritz Treeck
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, NW1 1AT London United Kingdom
| | - Michael L Reese
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, TX 75390;
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390
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OAS-RNase L innate immune pathway mediates the cytotoxicity of a DNA-demethylating drug. Proc Natl Acad Sci U S A 2019; 116:5071-5076. [PMID: 30814222 PMCID: PMC6421468 DOI: 10.1073/pnas.1815071116] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Drugs that cause epigenetic modification of DNA, such as 5-azacytidine (AZA), are used clinically to treat myelodysplastic syndromes and acute myeloid leukemia. In addition, AZA is being investigated for use against a range of different types of solid tumors, including lung and colorectal cancers. Treatment with AZA causes demethylation of DNA, thus increasing RNA synthesis, including the synthesis of double-stranded RNA, which is otherwise produced in virus-infected cells. We determined that cell death in response to AZA requires the antiviral enzyme RNase L. The results identify a drug target for enhancing the anticancer activity and reducing the toxicity of AZA and related drugs. Drugs that reverse epigenetic silencing, such as the DNA methyltransferase inhibitor (DNMTi) 5-azacytidine (AZA), have profound effects on transcription and tumor cell survival. AZA is an approved drug for myelodysplastic syndromes and acute myeloid leukemia, and is under investigation for different solid malignant tumors. AZA treatment generates self, double-stranded RNA (dsRNA), transcribed from hypomethylated repetitive elements. Self dsRNA accumulation in DNMTi-treated cells leads to type I IFN production and IFN-stimulated gene expression. Here we report that cell death in response to AZA treatment occurs through the 2′,5′-oligoadenylate synthetase (OAS)-RNase L pathway. OASs are IFN-induced enzymes that synthesize the RNase L activator 2-5A in response to dsRNA. Cells deficient in RNase L or OAS1 to 3 are highly resistant to AZA, as are wild-type cells treated with a small-molecule inhibitor of RNase L. A small-molecule inhibitor of c-Jun NH2-terminal kinases (JNKs) also antagonizes RNase L-dependent cell death in response to AZA, consistent with a role for JNK in RNase L-induced apoptosis. In contrast, the rates of AZA-induced and RNase L-dependent cell death were increased by transfection of 2-5A, by deficiencies in ADAR1 (which edits and destabilizes dsRNA), PDE12 or AKAP7 (which degrade 2-5A), or by ionizing radiation (which induces IFN-dependent signaling). Finally, OAS1 expression correlates with AZA sensitivity in the NCI-60 set of tumor cell lines, suggesting that the level of OAS1 can be a biomarker for predicting AZA sensitivity of tumor cells. These studies may eventually lead to pharmacologic strategies for regulating the antitumor activity and toxicity of AZA and related drugs.
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