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Li X, Ranjith-Kumar CT, Brooks MT, Dharmaiah S, Herr AB, Kao C, Li P. The RIG-I-like receptor LGP2 recognizes the termini of double-stranded RNA. J Biol Chem 2009; 284:13881-13891. [PMID: 19278996 PMCID: PMC2679488 DOI: 10.1074/jbc.m900818200] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 03/05/2009] [Indexed: 12/24/2022] Open
Abstract
The RIG-I-like receptors (RLRs), RIG-I and MDA5, recognize single-stranded RNA with 5' triphosphates and double-stranded RNA (dsRNA) to initiate innate antiviral immune responses. LGP2, a homolog of RIG-I and MDA5 that lacks signaling capability, regulates the signaling of the RLRs. To establish the structural basis of dsRNA recognition by the RLRs, we have determined the 2.0-A resolution crystal structure of human LGP2 C-terminal domain bound to an 8-bp dsRNA. Two LGP2 C-terminal domain molecules bind to the termini of dsRNA with minimal contacts between the protein molecules. Gel filtration chromatography and analytical ultracentrifugation demonstrated that LGP2 binds blunt-ended dsRNA of different lengths, forming complexes with 2:1 stoichiometry. dsRNA with protruding termini bind LGP2 and RIG-I weakly and do not stimulate the activation of RIG-I efficiently in cells. Surprisingly, full-length LGP2 containing mutations that abolish dsRNA binding retained the ability to inhibit RIG-I signaling.
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Affiliation(s)
- Xiaojun Li
- Department of Biochemistry and Biophysics, Texas A & M University, College Station, Texas 77843-2128
| | - C T Ranjith-Kumar
- Department of Biology and the Multidisciplinary Biochemistry Program, Indiana University, Bloomington, Indiana 47405
| | - Monica T Brooks
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0524
| | - S Dharmaiah
- Department of Biology and the Multidisciplinary Biochemistry Program, Indiana University, Bloomington, Indiana 47405
| | - Andrew B Herr
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0524
| | - Cheng Kao
- Department of Biology and the Multidisciplinary Biochemistry Program, Indiana University, Bloomington, Indiana 47405
| | - Pingwei Li
- Department of Biochemistry and Biophysics, Texas A & M University, College Station, Texas 77843-2128.
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102
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Oshansky CM, Zhang W, Moore E, Tripp RA. The host response and molecular pathogenesis associated with respiratory syncytial virus infection. Future Microbiol 2009; 4:279-97. [PMID: 19327115 DOI: 10.2217/fmb.09.1] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Since the isolation of respiratory syncytial virus (RSV) in 1956, its significance as an important human pathogen in infants, the elderly and the immunocompromised has been established. Many important mechanisms contributing to RSV infection, replication and disease pathogenesis have been uncovered; however, there is still insufficient knowledge in these and related areas, which must be addressed to facilitate the development of safe and effective vaccines and therapeutic treatments. A better understanding of the molecular pathogenesis of RSV infection, particularly the host-cell response and transcription profiles to RSV infection, is required to advance disease intervention strategies. Substantial information is accumulating regarding how RSV proteins modulate molecular signaling and regulation of cytokine and chemokine responses to infection, molecular signals regulating programmed cell death, and innate and adaptive immune responses to infection. This review discusses RSV manipulation of the host response to infection and related disease pathogenesis.
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Affiliation(s)
- Christine M Oshansky
- Department of Infectious Diseases, University of Georgia, Athens, GA 30602, USA.
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103
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A shared interface mediates paramyxovirus interference with antiviral RNA helicases MDA5 and LGP2. J Virol 2009; 83:7252-60. [PMID: 19403670 DOI: 10.1128/jvi.00153-09] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Diverse members of the Paramyxovirus family of negative-strand RNA viruses effectively suppress host innate immune responses through the actions of their V proteins. The V protein mediates interference with the interferon regulatory RNA helicase MDA5 to avoid cellular antiviral responses. Analysis of the interaction interface revealed the MDA5 helicase C domain as necessary and sufficient for association with V proteins from human parainfluenza virus type 2, parainfluenza virus type 5, measles virus, mumps virus, Hendra virus, and Nipah virus. The identified approximately 130-residue region is highly homologous between MDA5 and the related antiviral helicase LGP2, but not RIG-I. Results indicate that the paramyxovirus V proteins can also associate with LGP2. The V protein interaction was found to disrupt ATP hydrolysis mediated by both MDA5 and LGP2. These findings provide a potential mechanistic basis for V protein-mediated helicase interference and identify LGP2 as a second cellular RNA helicase targeted by paramyxovirus V proteins.
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104
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ISG56 is a negative-feedback regulator of virus-triggered signaling and cellular antiviral response. Proc Natl Acad Sci U S A 2009; 106:7945-50. [PMID: 19416887 DOI: 10.1073/pnas.0900818106] [Citation(s) in RCA: 157] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
IFN-stimulated gene 56 (ISG56) is one of the first identified proteins induced by viruses and type I IFNs. In this study, we identified ISG56 as a virus-induced protein associated with MITA, an adapter protein involved in virus-triggered induction of type I IFNs. Overexpression of ISG56 inhibited Sendai virus-triggered activation of IRF3, NF-kappaB, and the IFN-beta promoter, whereas knockdown of ISG56 had opposite effects. Consistently, overexpression of ISG56 reversed cytoplasmic poly(I:C)-induced inhibition of vesicular stomatitis virus (VSV) replication, whereas knockdown of ISG56 inhibited VSV replication. Competitive coimmunoprecipitation experiments indicated that ISG56 disrupted the interactions between MITA and VISA or TBK1, two components in the virus-triggered IFN signaling pathways. These results suggest that ISG56 is a mediator of negative-feedback regulation of virus-triggered induction of type I IFNs and cellular antiviral responses.
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105
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Pippig DA, Hellmuth JC, Cui S, Kirchhofer A, Lammens K, Lammens A, Schmidt A, Rothenfusser S, Hopfner KP. The regulatory domain of the RIG-I family ATPase LGP2 senses double-stranded RNA. Nucleic Acids Res 2009; 37:2014-25. [PMID: 19208642 PMCID: PMC2665237 DOI: 10.1093/nar/gkp059] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 01/15/2009] [Accepted: 01/21/2009] [Indexed: 12/24/2022] Open
Abstract
RIG-I and MDA5 sense cytoplasmic viral RNA and set-off a signal transduction cascade, leading to antiviral innate immune response. The third RIG-I-like receptor, LGP2, differentially regulates RIG-I- and MDA5-dependent RNA sensing in an unknown manner. All three receptors possess a C-terminal regulatory domain (RD), which in the case of RIG-I senses the viral pattern 5'-triphosphate RNA and activates ATP-dependent signaling by RIG-I. Here we report the 2.6 A crystal structure of LGP2 RD along with in vitro and in vivo functional analyses and a homology model of MDA5 RD. Although LGP2 RD is structurally related to RIG-I RD, we find it rather binds double-stranded RNA (dsRNA) and this binding is independent of 5'-triphosphates. We identify conserved and receptor-specific parts of the RNA binding site. Latter are required for specific dsRNA binding by LGP2 RD and could confer pattern selectivity between RIG-I-like receptors. Our data furthermore suggest that LGP2 RD modulates RIG-I-dependent signaling via competition for dsRNA, another pattern sensed by RIG-I, while a fully functional LGP2 is required to augment MDA5-dependent signaling.
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Affiliation(s)
- Diana A. Pippig
- Department of Chemistry and Biochemistry, Gene Center, Division of Clinical Pharmacology, Department of Internal Medicine, Section Gastroenterology and Endocrinology, Medizinische Klinik Innenstadt, Center for Integrated Protein Sciences and Munich Center for Advanced Photonics, Ludwig-Maximilians University Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Johannes C. Hellmuth
- Department of Chemistry and Biochemistry, Gene Center, Division of Clinical Pharmacology, Department of Internal Medicine, Section Gastroenterology and Endocrinology, Medizinische Klinik Innenstadt, Center for Integrated Protein Sciences and Munich Center for Advanced Photonics, Ludwig-Maximilians University Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Sheng Cui
- Department of Chemistry and Biochemistry, Gene Center, Division of Clinical Pharmacology, Department of Internal Medicine, Section Gastroenterology and Endocrinology, Medizinische Klinik Innenstadt, Center for Integrated Protein Sciences and Munich Center for Advanced Photonics, Ludwig-Maximilians University Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Axel Kirchhofer
- Department of Chemistry and Biochemistry, Gene Center, Division of Clinical Pharmacology, Department of Internal Medicine, Section Gastroenterology and Endocrinology, Medizinische Klinik Innenstadt, Center for Integrated Protein Sciences and Munich Center for Advanced Photonics, Ludwig-Maximilians University Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Katja Lammens
- Department of Chemistry and Biochemistry, Gene Center, Division of Clinical Pharmacology, Department of Internal Medicine, Section Gastroenterology and Endocrinology, Medizinische Klinik Innenstadt, Center for Integrated Protein Sciences and Munich Center for Advanced Photonics, Ludwig-Maximilians University Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Alfred Lammens
- Department of Chemistry and Biochemistry, Gene Center, Division of Clinical Pharmacology, Department of Internal Medicine, Section Gastroenterology and Endocrinology, Medizinische Klinik Innenstadt, Center for Integrated Protein Sciences and Munich Center for Advanced Photonics, Ludwig-Maximilians University Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Andreas Schmidt
- Department of Chemistry and Biochemistry, Gene Center, Division of Clinical Pharmacology, Department of Internal Medicine, Section Gastroenterology and Endocrinology, Medizinische Klinik Innenstadt, Center for Integrated Protein Sciences and Munich Center for Advanced Photonics, Ludwig-Maximilians University Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Simon Rothenfusser
- Department of Chemistry and Biochemistry, Gene Center, Division of Clinical Pharmacology, Department of Internal Medicine, Section Gastroenterology and Endocrinology, Medizinische Klinik Innenstadt, Center for Integrated Protein Sciences and Munich Center for Advanced Photonics, Ludwig-Maximilians University Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Karl-Peter Hopfner
- Department of Chemistry and Biochemistry, Gene Center, Division of Clinical Pharmacology, Department of Internal Medicine, Section Gastroenterology and Endocrinology, Medizinische Klinik Innenstadt, Center for Integrated Protein Sciences and Munich Center for Advanced Photonics, Ludwig-Maximilians University Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
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